1. General Principles & Basic Science MCQs

Mirror therapy is a useful technique to improve phantom pain in amputees. Phantom limb pain is a painful sensation that is perceived within a body part that no longer exists.Under mirror therapy, a patient is allowed to feel the imaginary movement of the removed body part behaving as normal body movement through a mirror. The mirrorimage of the normal body part helps reorganize and integrate the mismatch between proprioception and visual feedback of the amputated segment.Tilak et al. performed a randomized controlled trial of 26 patients with phantom limb pain, and found that mirror therapy as well as transcutaneous electrical nerve stimulation both significantly improved pain scores, but no difference was seen between the two groups. They recommend use of both modalities in treatment of phantom limb pain, as they are noninvasive and inexpensive.Chan et al. reviewed 22 patients utilizing mirror therapy for amputation related phantom limb pain, and found that patients reported a significant decrease in pain when utilizing this treatment modality as compared to covered mirror therapy or mental imagery therapy.Illustration A shows a patient with an upper extremity amputation using a mirror to perform movements during a mirror therapy session.Incorrect Answers:

Autologous bone is used to help promote bone healing in fractures and to provide structural support for reconstructive surgery, and can be harvested from the iliac crest, femur, or other areas. The results of autologous bone grafting are more predictable than the use of xenografts, cadaveric allografts, or synthetic bone substitutes because autologous bone grafts provide osteoinductive and osteoconductive properties, are not immunogenic, and are usually well incorporated into the graft site.Arrington et al reviewed 414 consecutive iliac crest harvest procedures and reported a 10% rate of minor complications and 5.8% of major complications (deep infection, nerve injuries, herniation, fractures, hematomas). They note that with proper surgical technique, the incidence of the complications can be minimized.Ahlmann et al compared the morbidity related to the harvest of anterior iliac crest bone graft with that related to the harvest of posterior iliac crest bone graft and to determine differences in functional outcome. The rates of both minor complications (p = 0.006) and all complications (p = 0.004) were significantly higher after the anterior harvest procedures than they were after the posterior procedures. The postoperative pain at the donor site was significantly more severe (p = 0.0016) and of significantly greater duration (p= 0.0017) after the anterior harvests.Which of the following statements is inaccurate in describing the origin and purpose of the Institutional Review Boards (IRB)?Began with the Nuremberg Code of Medical Ethics, which was developed by the Nuremberg Military Tribunal after the investigation of Nazi physiciansFetuses, pregnant women, and children are considered vulnerable populations but prisoners are notEmphasizes dignity and autonomy, and encompasses informed consent (quid vide)The process for obtaining informed consent for patients included in clinical trials is mandated by the Institutional Review Board (IRB).Requires fair selection of subjects and equal distribution of the benefits and burdens of researchFetuses, pregnant women, prisoners, and children are all considered vulnerable populations by Institutional Review Boards (IRB). The process for obtaining informed consent for patients included in clinical trials is mandated by the IRB.The article by Fisher is a commentary that reviews the clinical trials industry. She urges researchers to communicate the larger details of the research enterprise to patients and to compensate for asymmetrical power relations in society as a whole. Without these things, she believes, it will be impossible to protect against misunderstandings and therapeutic misconceptions.Which of the following best describes a Bonferroni correction?An analysis that starts with a particular probability of an event (the prior probability) and incorporates new information to generate a revised probability (a posterior probability)Human behavior that is changed when participants are aware that their behavior is being observed.Used to assess the relationship between two normally distributed continuous variablesA post-hoc statistical correction made to P values when several dependentor independent statistical tests are being performed simultaneously on a single data setThe ability of a study to detect the difference between two interventions if one in fact existsA Bonferroni correction is a post-hoc statistical correction made to P values when several dependent or independent statistical tests are being performed simultaneously on a single data set.To perform a Bonferroni correction, divide the critical P value (alpha level) by the number of comparisons being made. For example, if 10 hypotheses are being tested, the new critical P value would be (alpha level)/10. The statistical power of the study is then calculated based on this modified P value.Guyatt et al. discusses hypothesis testing and the role of alpha levels and P values. They report that the Bonferroni correction is derived from testing a dependent or independent hypotheses on a set of data and finding that the probability of a type I error is offset by testing each hypothesis at a statistical significance level divided by the number of times what it would be if only one hypothesis were tested.Incorrect Answers:A 10-year-old child falls from a standing height and sustains the injury shown in Figure A. Her medical history includes hearing defects and the facial appearance shown in Figure B. In addition to operative fixation of her fracture she is scheduled to receive cyclical intravenouspamidronate administration as a treatment after the fracture is healed. Which of the following is associated with this form of treatment?No change in bone painNo change in future fracture incidenceAn increase in osteoblast densityAn increased risk of secondary osteosarcomaAn increase in bone densityThe history and images are consistent with osteogenesis imperfecta (OI). Olecranon avulsion fractures are often seen in patients with OI and children presenting with these should be evaluated for OI. The clinical image of blue sclera can also be a characteristic finding in patients with OI. The Bisphosphonates have been shown to decrease fracture incidence and bone pain while improving bone density and overall function in OI patients.Zeitlin et al performed a Level 5 review of OI. They state that Sillence Types I through IV are a mutation in the COL1A1 and COL1A2 genes that encode type I collagen. They report that cyclical intravenous pamidronate administration reduces bone pain and fracture incidence, and increases bone density andlevel of ambulation.Burnei et al also performed a Level 5 review of OI. They report that the use of bone marrow transplantation to increase osteoblast density in OI patients is currently beingresearched as a potential treatment of OI.A 35-year-old male presents with pain and limited range of motion 3 months after arthroscopic Bankart repair of his right shoulder. His postoperative course included a continuous intra- articular infusion pump for 3 days, use of a sling for 4 weeks, and initiation of passive range of motion below the level of the shoulder. At 4 weeks postoperatively he started active range of motion exercises, and started an isotonic strengthening program at the 9 week interval. Which of the following options is the MOST appropriate step in his management?Reassurance and appropriate followupFocused physical therapy on aggressive ROM exercises and modalitiesIntra-articular injection of corticosteroids to decrease post-operative inflammationShoulder radiograph series to assess for chondrolysisArthroscopic vs open Bankart revision surgery for failed repairThe above patient was issued an intra-articular infusion of lidocaine for pain control after his surgery and may have developed shoulder chondrolysis. This complication after the use of intra-articular pumps has recently become more well known. The U.S. Federal drug and Administration (FDA) has issued a warning on the adminstration of continuous intra-articular infusion of local anesthestics for pain control.The FDA has reviewed 35 cases of patients developing chondrolysis after intra- articular infusions, some being as early as 2 months after their surgery. The average time of diagnosis in these cases with chondrolysis were at an average of 8.5 months after the infusion. The majority of the reported cases occurred following shoulder surgeries. Joint pain, stiffness, and loss of motion were the most common physical complaints. As a result of their findings, the FDA issueda warning for surgeons to be aware and monitor for signs and symptoms of chondrolysis.Illustration A shows a radiograph consistent with chondrolysis in a patient status post arthroscopic Bankart repair. This image shows the loss of joint height in the glenohumeral joint due to chondrolysis. Also, 2 suture anchors are visible as well in the glenoid from the Bankart repair. Illustration B shows an arthroscopic image of chondrolysis and Illustrations C and D demonstrate chondrolyis viewed from an open approach.Regarding bone densitometry, a T-score of -3.5 is defined as which of the following?Normal boneOsteopeniaAge appropriate bone lossOsteoporosisNone. One cannot make this diagnosis without further information.A T-score of -3.5 is defined as osteoporosis, regardless of the other clinical factors.As described in the review by Kanis et al., the World Health Organization (WHO) has defined the following categories based on bone density in white women:Normal bone: T-score greater than -1 Osteopenia: T-score between -1 and -2.5 Osteoporosis: T-score less than -2.5The WHO committee did not have enough data to create definitions for men or other ethnic groups. T-score is a comparison of a patient's BMD to that of a healthy thirty-year- old of the same sex and ethnicity. Z-score is the number of standard deviations a patient's BMD differs from the average BMD of their age, sex, and ethnicity.A 67-year-old female presented 2 months ago to her primary care physician with left sided thigh pain. A radiograph was taken at that time and is shown in Figure A. She was diagnosed at that time with a quadriceps strain and given a prescription for ibuprofen and physical therapy. She is now in the emergency room with severe left thigh pain and inability to bear weight on the left lower extremity after bending down to tie her shoes. She denies any constitutional symptoms. A current radiograph from the emergency room is shown in Figure B. Which of the following most likely explains this patient's fracture?Long-term corticosteroid useSecondary malignancy arising from Paget diseaseLong-term alendronate useLong-term ergocalciferol useShort-term teraparatide useSubtrochanteric stress reaction (Figure A) and low-energy transverse fracture (Figure B) is a complication of long-term bisphosphonate use documented in the literature. Of note, a healed right sided subtrochanteric femur fracture is also visualized in Figure A.Neviaser et al conducted a Level 4 study of 70 patients with low energy femur fractures. They found that a simple, transverse pattern and hypertrophy of the diaphyseal cortex are associated with alendronate use with 98% specificity. They report that the average alendronate usage time was 6.9 years in patients exhibiting this pattern of fracture.Capeci et al performed a Level 4 review of alendronate therapy and its association with unilateral low-energy subtrochanteric and diaphyseal femur fractures. They recommended consideration of discontinuing alendronate with the consultation of an endocrinologist if a fracture occurs. They also recommend routine contralateral leg surveillance after to rule out contralateral stress fracture. If contralateral stress fracture is found, it it is recommended that it is treated with prophylactic intramedullary fixation.Imaging typically shows lateral cortical thickening in the subtrochanteric femur as demonstrating on the coronal and axial CT scans shown in Illustration A and B, respectively.In the study by Moseley et al published in the New England Journal of Medicine, 180 patients with knee osteoarthritis were randomly assigned via sealed envelope to receive arthroscopic débridement, arthroscopic lavage, or placebo surgery. Outcomes were assessed by blinded evaluators at several points over a 2 year periodwith the use of five self-reported pain and function scores. There was a greater than 90% follow-up in the study. This study is best described as having which level of evidence?Therapeutic study, evidence level ITherapeutic study, evidence level IIDiagnostic study, evidence level IDiagnostic study, evidence level IIPrognostic study, evidence level ITherapeutic studies investigate the results of treatment. Level 1 evidence includes randomized controlled trial with statistically significant difference or no statistically significant difference but narrow confidence interval.A level II therapeutic study would include a lesser-quality randomized controlled trial (eg,<80% follow-up, no blinding, or improper randomization). A non-randomized prospective cohort study that compares the results of treatment or systematic reviews of level II studies or level I studies with heterogenous results would also be considered a level II study.Prognostic studies investigate the effect of a patient characteristic on the outcome of disease. Diagnostic studies investigate the efficacy of a diagnostic test. Illustration A is a table detailing the levels of evidence.A clinical trial is underway for patients with wrist extensor tendinitis. One group of 100 patients are treated with short arm casting. Another group of 100 patients are treated with physical therapy. During analysis of the results, it becomes apparent that 30 patients in the physical therapy group did not complete the full course of physical therapy. Despite not completing a full course of physical therapy, these 30 patients were included in the physical therapy group for analysis. This analysis is an example of which of the following?Per-protocolCrossover analysisIntent-to-treatBayesian analysisEffect sizeThe following is an example of intent-to-treat analysis.The intent-to-treat approach aims to keep similar groups similar by notallowing for patient selection based on post-randomization outcomes (including failure to comply with the protocol). This type of analysis ensures the power of randomization so that important unknown variables that impact outcome are likely to be dispersed equally in each comparison group. Conversely, a per- protocol comparison in a clinical trial excludes patients who were not compliant with the protocol guidelines.Berger et al., in a Level 5 review, discuss many of the principles beyond randomization that are critical for preserving the comparability of the different groups. They report that masking, allocation concealment, restrictions on the randomization, adjustment for prognostic variables, and the intent-to-treat approach to data analysis are important features of designing a good clinical trial.Incorrect Answers:guidelinesA 32-year-old male is being seen in your office for evaluation of a possible rotator cuff tear. He has been seen in your office by one ofyour partners previously after surgical treatment of a femoral shaft fracture. How much time has to pass since last evaluation or treatment in your group for this patient to revert to a new patient under CPT guidelines?6 months1 year18 months2 years3 yearsBy CPT definition, a new patient is “one who has not received any professional services from the physician, or another physician of the same specialty who belongs to the same group practice, within the past three years.” By contrast, an established patient has received professional services from the physician or another physician in the same group and the same specialty within the prior three years.The referenced study by Shalowitz reviewed 500 Medicare claims and found an overall coding error rate of 32.4%, with high levels of consultation coding errors. He reports that changing ambulatory consultation codes to those for new patient visits would save Medicare $534.5 million per year.As a result of this study, as well as others, Medicare does not recognize consultation codes.A 55-year-old healthy female presents for a routine physical exam. When discussing bone health and osteoporosis prevention, what dose of calcium and vitamin D should be recommended for daily consumption?1,500mg of calcium and 1,000 IUs of vitamin D2,200mg of calcium and 1,000 IUs of vitamin D750mg of calcium and 5,000 IUs of vitamin D750mg of calcium and 10,000 IUs of vitamin D2,200mg of calcium and 5,000 IUs of vitamin DThe National Osteoporosis Foundation recommends a daily intake of 1,200- 1500mg of calcium 800-1,000 IUs of vitamin D for adults over the age of 50.The review article by Gehrig et al discusses the factors surrounding osteoporosis that can be modified to optimize fracture risk reduction. They report that non-prescription interventions such as calcium and vitamin D supplementation, fall prevention, hip protectors, and balance and exercise programs are treatment options.What is the function of the core binding factor alpha-1 (Cbfa1/Runx2)?Phosphorylation and intracellular activation of signal transducers and activators of transcription (STATs)Chemotaxis of mesenchymal stem cells to sites of skeletal fracturesTumor-induced osteolysisOsteoclastic apoptosisOsteoblastic differentiationAs described by Ducy et al., Cbfa1/Runx2 is a key transcription factor associated with osteoblast differentiation, skeletal morphogenesis, and acts as a scaffold for nucleic acids and regulatory factors involved in skeletal gene expression. A stop codon mutation in the Cbfa 1 gene causes cleidocranial dysplasia. Stem cell chemotaxis (moving to various sites in the body) is accomplished through a variety of cytokines, one of which is platelet derived growth factor. Tumor-induced osteolysis occurs secondary to tumor-produced cytokine activation of osteoclasts. Osteoclastic apoptosis occurs secondary to bisphosphonates.Ballock and O'Keefe review the development, growth, and complex cytokine interaction required for normal growth plate function.A 20-year-old male is involved in motor vehicle collision and sustains a depressed tibial plateau fracture. When performing surgery, if calcium sulfate is used as the primary bone substitute void filler, an increase in which of the following outcomes may be expected as compared to autograft?Increased complications due to serous drainageImproved clinical outcomes as shown by more rapid time to healingImproved clinical outcomes as shown by SF-36 scoresIncreased complications due to autoimmune reactions and graft rejectionEquivalent complication rates and clinical outcomesCalcium sulfate bone graft substitute has demonstrated an increased rate of serous drainage at the surgical site. Evidence examining the use of calcium sulfate in the treatment of bone nonunions revealed a significant failure rate, suggesting that this material, used in isolation, is not optimal to promote union in that setting.Beuerlein and Mckee reviewed the literature, showing that calcium sulfate isan effective void filler in metaphyseal defects after impacted fracture reduction (calcaneus, tibial plateau) or simple bone cysts. However, they report that calcium sulfate is associated with serous wound drainage especially when used at subcutaneous sites and in amounts greater than 20ml.Ziran et al present a series of 41 patients undergoing bone grafting for atrophic/avascular nonunions with adjunctive calcium sulfate-demineralized bone matrix (Allomatrix). Of the 41 patients, 13 (32%) had drainage that necessitated surgical procedures and 14 (34%) developed a deep infection.A 46-year-old female begins to have personality changes, cognitive decline, and chorea. Her father began having similar but less severe symptoms at age 55 before passing away 6 years later. One of her 2 older siblings has also begun to show deterioration. Which of the following describes the hereditary pattern of this disease?Autosomal dominant with variable penetranceAutosomal recessive with variable penetranceX-linked recessiveAutosomal dominant with anticipationAutosomal dominant with imprintingThis clinical vignette describes a patient with Huntington's disease. Huntington's disease has an autosomal dominant hereditary pattern with anticipation.Anticipation is a term used to describe trinucleotide repeatdisorders that if passed on, will present earlier and more severely in affected subjects than in their affected parent. In Huntington's disease, it is due to a "CAG" trinucleotide repeat on chromosome 4. Subjects with an affected parent have a 50% chance of inheriting the disease from them, and if present will have more severe disease.Deighton et al provide a review on the genetics of musculoskeletal disease including the hereditary pattern of anticipation.All of the following are indications for locked plating technology EXCEPT:Periarticular fracture with metaphyseal comminutionFracture in osteoporotic boneBridge plating for severely comminuted fracturesCompression plating of transverse fracturePlating of fractures where anatomical constraints prevent plating on the tension side of the boneLocked plates are indicated for indirect fracture reduction, diaphyseal/metaphyseal fractures in osteoporotic bone, bridging severely comminuted fractures, and the plating of fractures where anatomical constraints prevent plating on the tension side of the bone.Locked plates and conventional plates rely on completely different mechanical principles to provide fracture fixation and in so doing they provide different biological environments for healing. Approaches to internal fixation have become more biologic. Greater emphasis is placed on vascularity and soft tissue integrity. Locked plates, analogous to rigid internal fixators, can provide relative stability favorable to secondary fracture healing. If applied appropriately, they canavoid soft tissue compromise. The key to this new generation of plates is the locking mechanism of the screw to the plate, which provides angular stability and avoids compression of the plate to the periosteum. Favorable biomechanical and clinical results continue to expand the number of appropriate indications for use of locked plating devices, although exact indications for their use have yet to be precisely defined.The referenced articles by Haidukewych and Egol et al are reviews of the biomechanical characteristics of locked plating technology.Which of the following lists these materials in order of increasing modulus of elasticity?:Cortical bone; Titanium; Cobalt-chrome; Stainless steel; CeramicTitanium; Cortical bone; Ceramic; Cobalt-chrome; Stainless steelCortical bone; Titanium; Stainless steel; Cobalt-chrome; CeramicStainless steel; Titanium; Cortical bone; Ceramic; Cobalt ChromeCortical bone; Stainless steel; Titanium; Cobalt-chrome; CeramicCortical bone has the lowest modulus of elasticity of the materials listed, followed by titanium, stainless steel, cobalt-chrome alloy, then ceramic.Young's modulus of elasticity is the ratio of stress to strain, and represents the stiffness of a material and its ability to resist deformation when placed under tension. Of the materials listed, titanium has the stiffness closest to cortical bone. Ceramic has the highest modulus of elasticity, making it the most stiff of the materials listed.Illustration A (from Miller's Review) shows the relative stiffnesses of various orthopaedically relevant materials. Young's modulus is the slope of the lines shown. Illustration B (Google images) charts their Young's Modulus.Incorrect answers:Which of the following substances increases the chondrogenic phenotype of intervertebral disk cells and matrix synthesis?OsteoprotegrinOsteonectinHyperosmotic salineCorticosteroidsBone morphogenic proteinsBone morphogenic proteins have been shown to increase chondrogenic phenotype expression and increase matrix synthesis of the intervertebral disc in animal studies.Bone morphogenetic protein-2, bone morphogenetic protein-7, andtransforming growth factor-beta are morphogens that have been shown to alter the phenotype of target cells without increasing cellular proliferation. Within the intervertebral disk, these factors have the potential to increase the chondrogenic phenotype among disk cells, and this results in the increased production of the disk matrix. Mitogenic molecules, such as insulin-like growth factor-1 and fibroblast growth factor, function to increase cellular proliferation.Miyamoto et al. evaluated rabbits that underwent annulus fibrosus (AF) injury where they either injected a control or BMP into the nucleus pulposus. The BMP injection significantly restored disc height and improved the modulus as compared to control injections. They concluded the biochemical data suggested that the OP-1-induced restoration of the disc space was a consequence of the increased activity of anabolic pathways that resulted in biochemical changes in the IVD.Kim et al. evaluated mRNA levels of BMP-2, BMP-7, and TGF-beta in a rabbit model of intervertebral discs. Compared to young rabbits, old rabbits generally had higher levels of mRNA expression of these three cytokines in both the annulus fibrosus and nucleus pulposus. The similar patterns of up-regulation in gene expression with age shown by these 3 anabolic cytokines suggest a common pathway in terms of regulation and transcription in the early stage of disc degeneration.Incorrect Answers:A colleague is struggling to obtain a perfect lateral radiograph for distal locking screw placement. Other than good technique, how might the surgeon best reduce the amount of radiation exposure to the patient and personnel when using fluoroscopy?The use of continuous fluoroscopy while manipulating the legStanding directly behind the cathode ray tubeAdvising the technician to position the fluoroscopy beam on commandPlacement of the image intensifier receptor as close to the patient as possiblePlacement of the cathode ray tube as close to the patient as possiblePlacing the image intensifier as close as clinically possible to the patient, scatter radiation exposure to the personnel is minimized.Numerous steps have been described to decrease radiation in the operating room. They include:Decrease time of exposureDecrease dose of exposureBeam collimationThe use of mini C armInverting the C arm (shortens distance between body part and collection surface)Surgeon’s control of the C armUse of protective equipment (glasses, thyroid shields, aprons)Increase the distance from the X ray sourceManiscalco et al. compared the amount radiation exposure during open lumbar microdiscectomy and minimally invasive microdiscectomy. MIS lumbar microdiscectomy cases expose the surgeon to significantly more radiation than open microdiscectomy.Interestingly, standing in a substerile room during x- ray localization in open cases is not fully protective.Illustration A shows an image of radiation scatter with fluoroscopy. Radiation hits the patient’s tissue, interacts and then changes direction. The greatest dose received is directly perpendicular to the fluoroscopy and next to the patient.Incorrect Answers:A 72-year-old active man presents with chronic right-sided pelvic pain for the last 2 years. His radiographs are depicted in Figure A. He has tried multiple courses of activity modification and anti- inflammatory medications to no avail. His orthopedic oncologist performs a biopsy (depicted in Figure B) and elects to initiate Zoledronate. Which of the following is a known complicationassociated with this treatment if rendered long-term?Malignant degeneration to osteosarcomaMalignant degeneration to chondrosarcomaMalignant degeneration to fibrosarcomaAtypical distal femur transverse fracturesOsteonecrosis of mandibleThis patient's pelvic radiograph reveals cortical thickening, coarse trabeculae, and sclerosis, which is characteristic of Paget's disease, depicted in the histological section in Figure B. Bisphosphonate treatment is an appropriate treatment for Paget's disease. However, long-term administration of intravenous (IV) bisphosphonates (i.e.Zoledronate) may result in osteonecrosis of the jaw.Osseous lesions from Paget's disease have increased osteoclastic bone resorption, marrow fibrosis, increased bone vascularity, and increased disorganized bone formation, resulting in a mosaic (woven and lamellar bone) appearance on histology. Asymptomatic patients may be treated withobservation and symptomatic management reserved as first-line management. When recalcitrant to symptomatic management, bisphosphonate therapy helps control osteoclast lytic activity and reduces pain. However, when administered long-term, side-effects may include atypical subtrochanteric femur fractures and jaw osteonecrosis (especially when given IV). Administration of Teriparatide (Forteo) is contraindicated in these patients due to the increased risk of Pagetoid malignant transformation. Malignant transformation to Paget's sarcoma occurs in 1% of patients.Langston et al. performed a randomized trial of intensive bisphosphonate treatment versus symptomatic management in Paget's disease of bone. They reported that while serum alkaline phosphatase (ALP) levels were significantly lower in the intensive treatment group than in with the symptomatic treatment group, there was no difference in the quality of life, pain scores, hearing loss, or rates of surgical intervention in the two cohorts. They concluded thatstriving to maintain normal ALP levels with intensive bisphosphonate therapy confers no clinical advantage over symptom-driven management in patients with Paget's disease of bone.Figure A demonstrates Paget's disease of the right hemipelvis. Figure B demonstrates thehistology of Paget's disease of bone (woven bone and irregular broad trabeculae with disorganized cement lines in a mosaic pattern). Illustration A and B demonstrate osteonecrosis of the jaw and atypical subtrochanteric femur stress fracture, respectively, after long-term bisphosphonate use.Incorrect Answers:A long oblique diaphyseal fracture is internally fixed with 2 lag screws. There is 2 mm of residual fracture fragment gap following screw fixation. This construct has which of the following compared to a comminuted diaphyseal fractureinternally fixed with a long bridge plating technique?Greater interfragmental strainGreater ductilityGreater primary Haversian remodelingGreater union rateGreater callus volume formationA long oblique diaphyseal fracture with 2 mm of residual displacement after being internally fixed with lag screws has greater interfragmental strain than comminuted fractures treated with bridge plating or fractures that are anatomically reduced and internally fixed.Perrens’ theory of strain states that there is a relationship between decreasing strain and increasing the potential for osteogenesis across a fracture or fusion site. The strain theory states that for two given fracture segments, the healing interface will possess a force- generated motion potential that is contingent on the stability of the original fixation construct. Mathematically, the strain forany given force is equal to the change in the interface length divided by the original interface length. Therefore, with an unstable construct, the healing gap may undergo excessive motion with resultant increasing strain. It has been shown that strain of less than 2% will yield absolute stability and subsequent primary bone healing. Comminuted fractures have multiple fracture lines therefore the force is dissipated over multiple fracture lines and interfragmentary strain is decreased.A 75-year-old woman presents with acute severe back pain after sustaining a mechanical fall while walking out of her yard. She denies pain in her buttocks or legs. On physical exam she has point tenderness over the L1 spinous process. Figure A depicts her current radiograph. Which of the following statements is true regarding here underlying metabolic condition and associated pathology?Kyphoplasty is indicated within the first week if the pain is severe enough to warrant narcotic medication.Her underlying metabolic bone condition leads to decreased bone quantity with normal bone quality.A DEXA T-score of -2.1 in this individual would confirm the diagnosis of osteoporosis according to the WHO.A 25-hydroxy Vitamin D level of 16ng/mL in this individual would confirm the diagnosis of osteoporosis according to the WHO.The fracture pattern in Figure A is the third most common fragility fracture in the United StatesThis clinical presentation is consistent with an L1 osteoporotic compression fracture due to underlying osteoporosis. Osteoporosis is characterized by decreased bone quantity with normal bone quality.FOR ALL MCQS CLICK THE LINK ORTHOMCQ BANKVertebral compression fractures are the most common type of fragility fracture in patients with osteoporosis. Management should begin with a proper evaluation to identify the etiology of the fracture and appropriate intervention to rectify the underlying pathology.Evaluation includes bone densitometry, lab testing of Vitamin D and calcium. The World Health Organization (WHO)classifies bone density in postmenopausal women based on T-scores, with classification based on the lowest T-score of the spine, femoral neck, trochanter, or total hip. Osteoporosis is defined by T-scores 2.5 or greater standard deviations below the peak bone mass of a 25-year-old individual.Gehrig et al. published an Instructional Course Lecture on the management and treatment strategies for orthopaedic surgeons. They reported that osteoporosis may be present in patients with and without fracture and that the ultimate goal in managing and treating osteoporosis is to optimize fracture risk reduction. They recommended non-pharmacologic interventions including calcium, vitamin D supplementation, fall prevention, hip protectors, and balance and exercise programs to minimize fracture risk.The United States Preventive Services Task Force published clinical guidelines on osteoporosis screening. They recommended screening for osteoporosis in women aged 65 years or older and in younger women whose fracture risk is equal to or greater than that of a 65-year-old white woman who has no additional risk factors. They concluded that the current evidence is insufficient to assess the balance of risks and benefits of screening for osteoporosis in men.Figure A depicts an L1 vertebral compression fracture. Incorrect Answers:year-old woman with long standing rheumatoid arthritis presents with worsening bilateral foot pain. She sees a podiatrist for shaving of her plantar forefoot calluses. She has tried orthotics and custom shoes but notes worsening foot pain that is limiting her daily activities. Plain radiographs of her feet are pictured in Figure A. Whichof the following images depicts the surgical treatment that would result in the best functional outcome for this patient?This patient has a classic rheumatoid arthritis (RA) forefoot deformity and would benefit most from first metatarsophalangeal (MTP) joint fusion, hammertoe correction and lesser metatarsal (MT) head resections, pictured in Figure E.Nearly 90% of patients with chronic RA develop forefoot deformities, most commonly hallux valgus, fixed hammering of the lesser toes and subluxation/dislocation of the lesser MTP joints. Nonoperative management includes orthotic use and shoewear modification. The gold standard surgical treatment involves stabilization of the first ray with a first MTP joint fusion, hammertoe correction and resection of the lesser MT heads (Hoffman-Clayton procedure).Coughlin et al highlighted that achievement of stable realignment of the first ray is the key factor in reconstruction of a RA forefoot. Stable fusion of the first MTP joint increases weight-bearing along the medial column, minimizes stress on the lesser MTP joints and protects the relocated plantar fat pad. Patients who underwent first MTP fusion, lesser MT head resections and open hammertoe correction had a high level of satisfaction postoperatively.Mann et al performed a retrospective review of 20 patients with severe RA forefoot deformities who underwent first MTP joint fusion. These patients demonstrated an increase in weight-bearing of the hallux and resultant decrease in metatarsalgia and plantar callosities compared to patients who underwent a first MTP resection arthroplasty(Keller arthroplasty). The patients in this study noted significant functional improvement postoperatively and no patients required custom shoes or orthotics.Figure A is an AP radiograph of bilateral feet demonstrating the classic RA forefoot deformity with severe hallux valgus, dislocation of the lesser MTP joints and erosive changes of the MT heads. Figure B shows a hallux valgus realignment procedure with a distal osteotomy and hammertoe correction with a 2nd MT shortening osteotomy (Weil osteotomy), proximal interphalangeal (PIP) joint resection and K wire fixation. Figure C displays a first tarsometatarsal (TMT) joint fusion (Lapidus procedure) and Weil osteotomiesof the 2nd through 4th MTs. Figure D demonstrates a first MTP joint fusion and Weil osteotomies of the 2nd through 4th MTs. Figure E shows a first MTP joint fusion, resection of the 2nd through 5th MT heads and hammertoe correction with PIP joint resection and K wire fixation. Figure F displays a resection of thefirst MTP joint proximal phalanx base (Keller arthroplasty) and hammertoe correction with PIP joint resection and K wire fixation.Incorrect Responses:What type of fracture healing occurs in a femoral shaft fracture treated with an intramedullary nail?Primary fracture healingSecondary fracture healingExtramembranous ossificationHaversian remodelling"Cutting cone" remodellingIntramedullary nails function as internal splints that allow for secondary fracture healing.Secondary bone healing involves responses in the periosteum and external soft tissues. Here both committed osteoprogenitor cells and uncommitted undifferentiated mesenchymal cells contribute to the process of fracture healing by recapitulation of embryonic intramembranous ossification and endochondral bone formation. The response from the periosteum is a fundamental reaction to bone injury and is enhanced by motion and inhibited by rigid fixation.Bong et al. reviewed the biomechanics and biology of long bone fracture healing with Intrameduallary nailing. They showed that reaming and the insertion of intramedullary nails can have early deleterious effects onendosteal and cortical blood flow initially. However, the canal reaming appears to have an overall positive effect at the fracture site as it increases extraosseous circulation and applies bone graft to the fracture site.Illustration A shows a series of radiographs of a fracture healed by secondary intention with an IM nail.Incorrect Answers:healing of bone.A 67-year-old woman sustained the injury shown in Figure A approximately 14 months ago, which was managed with closed reduction and casting. She presents with new symptoms of hyperalgesia, allodynia, and hyperhidrosis of her wrist. She denies any recent fevers or chills. Her current radiographs reveal a well-healed fracture without any significant malunion. What is thepathophysiology likely attributable to her current symptoms?Pre-ganglion brachial plexopathyAberrant inflammatory and vasomotor responseExaggerated vasoconstriction of the wrist and digital arteriesIncomplete glycosaminoglycan breakdown products causing dysfunctionConnective tissue disorderThe patient is presenting with complex regional pain syndrome (CRPS) after a healed distal radial fracture. The pathophysiology of CRPS is that of aberrant inflammatory and vasomotor response in a region of prior trauma resulting in pain out of proportion, skin discoloration, and vasomotor disturbances.Patients who develop CRPS often have a history of trauma, but the condition may also occur after surgery. Common symptoms of CRPS include hyperalgesia, often described as burning, throbbing, shooting, or aching. Patients may also experience hyperalgesia, allodynia, and hyperpathia. More objective signs of CRPS may include motor dysfunction (tremors, dystonia, loss of strength), skin, hair, and other trophic changes about the affected extremity, as are symptoms of autonomic dysfunction. CRPS is often sub- classified into 2 types. Type 1 is more common and does not involve specific nerve damage, whereas type 2 involves damage to a specific nerve.Hogan et al. reviewed the evaluation and treatment of complex regional pain syndrome. They report that although there are many divergent and often conflicting theories, the cause of the severe pain, alterations in regional blood flow, and edema noted in CRPS is unknown. They concluded that CRPS is a challenging diagnosis and as such should be managed by a multidisciplinary team, including chronic pain management specialists,physical therapists, and orthopedic surgeons.Shah et al. reviewed the diagnosis and treatment of CRPS. They reported that sweat quantification testing, skin thermography, and electromyography maybe useful in the diagnosis of CRPS, but these tests are often unreliable given is a lack of diagnostic sensitivity. They concluded that the treatment of CRPS remains controversial, and includes medications (antiepileptics, antidepressants, NSAIDS, bisphosphonates, free radical scavengers, vitamin C, and topical anesthetics), physical therapy, regional anesthesia, and neuro- modulation.Figure A depicts an extra-articular distal radius fracture. Illustration A depicts an example of a wrist affected by CRPS, with notably increased swelling, which is a common finding in patients afflicted with the disease.Incorrect Answers:After application of a unilateral tibial external fixator, it is observed that the frame does not provide sufficient rigidity across the fracture site. Altering the external fixator in which of the following ways will have the greatest impact on frame stiffness?Increasing the distance between pins in each fragmentIncreasing the pin diameterReducing the distance between bone and connecting barIncreasing the connecting bar diameterAdding one stacked connecting barWhile all of the aforementioned factors will increase frame stiffness, pin diameter has the greatest influence on stability of unilateral frames.Unilateral frames are distinguished from circular frames in that they are positioned on one side of the limb. The overall stability of the frame can be varied by altering the number of pins, the distance between pins, pin diameter, connecting rod diameter, number of connecting rods, distance between bone and connecting rods, and use of multiplanar fixation. The pin diameter has the biggest contribution, as the stiffness of the pin is correlated to the fourth power of its radius.Fragomen et al. looked at the mechanics of external fixation. They state that the diameter of the half Schantz pin should be less than one-third of the bone diameter to minimize the risk of fracture at the pin site. Unicortical half pins also increase the risk of fracture.Therefore, pins should be bicortical.Tencer et al. examined the mechanical properties of external fixation. They showed that frame rigidity could be maximized by increasing the pin separation distance in each fracture fragment, increasing the number of pins and decreasing the sidebar offset distance from bone.Illustration A shows a schematic of the factors contributing to frame stability. Incorrect Answers:Locking plate technology is least indicated for which of the following Figures?Of the fracture patterns listed, all have some indication for locking plate fixation except answer 2. Transverse midshaft both bone forearm fractures are typically treated with non- locked compression plating techniques.The use of locking plate fixation is an evolving topic in orthopaedics, and exact uses may vary. Well accepted indications for locking plate fixation include indirect fracture reduction, diaphyseal/metaphyseal fractures in osteoporotic bone, bridging of severely comminuted fractures, and plating of fractures where anatomical constraints prevent plating on the tension side of the bone (e.g. short segment fixation).Anglen et al. performed a level-IV meta-analysis of 33 papers reviewing the use and outcomes of locking plate fixation. They found no standard indications for use, and due to heterogeneity of the studies reviewed had no specificrecommendations for use.Cantu et al. presented a level-V review of the use of locking plate fixation. They cite 5 indications for use: metaphyseal or intra-articular fractures, highly comminuted fractures particularly involving diaphyseal and metaphyseal bone, osteoporotic bone, proximal tibia and distal femur fractures, and periprosthetic fractures. They also cite 4 relative contraindications: fractures best servedwith a construct other than a plate, severe soft tissue injury precluding placement of a plate, simple fracture patterns that can be adequately treated with non-locking constructs, and fractures that would require bending the plate.Figure A is a comminuted Schatzker VI tibial plateau fracture. Figure B is a transverse both bone forearm fracture. Figure C is an intra-articular pilon fracture. Figure D is a comminuted distal humerus fracture. Figure E Vancouver B1 periprosthetic hip fracture.Incorrect Answers:All of the following are true regarding osteocalcin EXCEPT which of thefollowing?It is the most prevalent non-collagenous protein in boneIt is expressed by mature osteoblastsIt is considered a marker for osteoblast differentiationIt is a glycoprotein that binds calciumHigher levels are correlated with increases in bone mineral density during osteoporosis treatmentPure fact question from basic science. “Osteocalcin is the most prevalent noncollagenous protein in bone” (from Miller's Review). It is expressed by mature osteoblasts and is a marker of osteoblast differentiation. Osteocalcin is the most specific marker of the osteoblast phenotype and is expressed only in mature osteoblasts. During osteoporosis treatment, serum levels correlatewith increases in bone mineral density. Osteonectin, not osteocalcin, is a glycoprotein that binds calcium.An otherwise healthy young male sustains a significantly comminuted fracture of the 2nd metacarpal shaft and undergoes external fixation as definitive management. The type of bony healing obtained with this treatment is similar to the bony healing for the appropriate treatment of all the following injuries EXCEPT?The patient has undergone external fixation for his 2nd metacarpal shaft fracture which is an example of enchondral healing (secondary bone healing) which occurs with non- rigid fixation, such as bracing, casting, external fixation, bridge plating, and intramedullary nailing. Of the images shown, Figure D is an example of a patient with an unstable Weber B ankle fracturewith a simple oblique pattern that would preferentially be treated with primary bone healing with ORIF (anatomic stability).Bone healing occurs via primary healing (intramembranous healing, absolute stability) or secondary healing (enchondral healing, relative stability) depending on the method of fixation. Fractures that require primary bone healing are ones in which anatomic reduction without callus formation is preferred (peri-articular fractures, both bone forearm fractures, non- comminuted ankle fractures with disruption of the ankle syndesmosis).Primary healing leads to healing via cutting cones and occurs without the production of any callus (which may impede rotation in both bone forearm fractures and cause articular malalignment in peri-articular and peri- syndesmotic fractures). Fractures that may be treated with secondary bone healing and callus formation, do not require anatomic stability and may have fracture site micromotion during the healing process. Intramedullary nailing, external fixation and closed treatment with bracing/splinting/casting all allow motion at the fracture site and lead to secondary bone healing.Perren reviews the biological and mechanical properties of bone remodeling and the complex interplay of patient, injury and surgical factors that influence healing. The use of relative stability fixation techniques allows the bone to overcome the initial excess strain at a fracture site and build a scaffold that brings the strain to more reasonable levels. The author stresses the importance of understanding bone biology to select optimal implant and methods of surgical fixation.Bong et al. reviewed the biomechanics and biology of long bone fracture healing with Intramedullary nailing. They showed that reaming and the insertion of intramedullary nails can have early deleterious effects onendosteal and cortical blood flow initially. However, the canal reaming appears to have an overall positive effect at the fracture site as it increases extraosseous circulation and applies bone graft to the fracture site.Figure A shows the AP and lateral radiographs of a segmental oblique midshaft tibia fracture. Figure B is an AP radiograph of an unstable intertrochanteric femur fracture with disruption of the calcar. Figure C shows the AP and lateral radiographs of a midshaft transverse femur fracture. Figure D shows the AP and lateral radiographs of a simple oblique weber B ankle fracture with medial clear space widening. Figure E shows a displaced 5th metacarpal neck fracture with dorsal angulation.Illustration A is the injury in Figure A treated with intramedullary nailing with resulted callus formation. Illustration B is the injury in Figure B treated with cephallomedullary nailing with resulting callus formation. Illustration C is the injury in Figure C treated with intramedullary nailing with resulting callus formation. Illustration D is the injury in Figure D treated with a lag screw and neutralization plating (anatomic stability). Illustration E is the injury in FigureE treated with closed reduction and casting with subsequent healing with callus formation.Incorrect Answers:This is an example of secondary bone healing.A 7-year-old recent immigrant presents with pain and tenderness over the legs. Physical exam shows the gums have a bluish-purple hue with areas of hemorrhages. A radiograph is shown in Figure A. In Figure B, what region of the growth plate is most affected in this condition?ABCDEThe clinical presentation and radiographs are consistent with scurvy. The radiographs show a dense band (White line of Frankl) at the growing metaphyseal end which is characteristic of scurvy. Scurvy is a disease resulting from a deficiency of vitamin C (ascorbic acid), which is required for the synthesis of collagen in humans. Impaired collagen synthesis in scurvy leads to fragile capillaries, resulting in abnormal bleeding, and altered bone formation at the growth plate. More specifically, scurvy affects the spongiosathe most (but not exclusively) in the metaphysis, which is depicted by region E in the illustration.It is considered optimal to obtain written informed consent for an elective surgical procedure in which of the following clinical settings?By the hospital risk manager upon admissionBy the nurse in pre-op holdingBy the surgeon in pre-op holdingBy the surgeon's scheduler greater than 7 days priorBy the surgeon in the office within 7 days priorThe reference by Bhattacharyya et al notes that the location where the informed consent was obtained is important. When informed consent was obtained by the operating surgeon in the office, there was a decreased risk of indemnity payment (p < 0.004). This finding is likely due to the effect of communication on malpractice claims. Poor communication has been established as the critical factor linked to malpractice claims. It seems logical that the physician-patient communication that occurs in the office is more interactive and substantive than discussions that occur on the hospital floor or in the preoperative holding area. A closed claims analysis conducted in Florida, which included 127 mothers of infants who had experienced permanent perinatal injuries and who subsequently sued their physicians, showed that nearly all complained that their physicians would not talk, answer questions,or listen. Clearly, the office is the best setting for quality discussions on informed consent to occur.A 45 year-old woman who has not reached menopause yet falls from a standing height and sustains a distal radius fracture. A DEXA scan reveals a T- score of -2.2. Which of the following treatments is indicated in this patient?1,700 mg of calcium1,200 mg of calcium1,700 mg of vitamin D1,200 mg of iron1,700 mg of PTHThe current recommendations for further prevention of any fragility fracture include 1200- 1500mg of elemental calcium intake per day and 400-800 IU of vitamin D per day. Of note, these doses are indicated only for prevention and not sufficient for active treatment of osteoporosis (T score less than -2.5).Medications that are approved by the FDA for active treatment of osteoporosis: alendronate, risedronate, raloxifene, estrogen, calcitonin. These medications and preventative measures help to reduce fragility fractures by as much as 50%.Freedman et al. performed a retrospective study that looked at a cohort of patients with fragility fractures and then looked at the type and frequency of osteoporosis related interventions. They found that only 60% of patients actually were either prescribed amedication, given a referral, or ordered additional workup (DEXA scan).Schulman et al. reviewed a series of 80 female patients regarding osteoporosis and bone health, and found that the outpatient sports medicine office setting was an excellent opportunity to educate patients on these topics. The patients' post-education test scores increased significantly after a brief counseling session, and increases in daily calcium intake and exercise levels were also seen.Hypophosphatasia is associated with which of the following laboratory findings?HyperbilirubinemiaDecreased urinary phosphoethanolamineDecreased urinary inorganic pyrophosphateDecreased serum phosphateDecreased serum alkaline phosphataseAlkaline phosphatase is a marker of bone formation and is elevated when bone formation is increased. Hypophosphatasia is an autosomal recessive disorder caused by an inborn error in the production of alkaline phosphatase (tissue- nonspecific isoenzyme of alkaline phosphatase: TNSALP), leading to low alkaline phosphatase levels. Increased urinary phosphoethanolamine is also diagnostic.Which of the following statements regarding COX-2 is FALSE?It causes mesenchymal stem cells to differentiate into osteoblastsCOX-2 knockout mice heal fractures more quickly than control miceCOX-2 is an enzyme which converts arachidonic acid to prostaglandin endoperoxide H2Most NSAIDS non-specifically inhibit both COX-1 and COX-2 enzymesThe expression of COX-2 is upregulated in several human cancersCycloxygenase-2 (COX-2,aka prostaglandin-endoperoxide synthase 2) is an enzyme which converts arachidonic acid to prostaglandin endoperoxide H2. COX-2 is not expressed under normal conditions, but elevated levels are found during general states of inflammation. Zhang et al and Simon et al have both studied the role of COX-2 with regard to fracture healing. Zhang et al createda COX-2 knockout mouse (one which does not express the COX-2 gene). This COX-2 knockout mouse has been shown to heal fractures more slowly than COX-1 knockoutmice or normal controls, thus identifying the role of COX-2 in general inflammation and bone repair. Zhang et al hypothesize that COX-2 causes mesenchymal progenitor cells to differentiate into osteoblasts, thus promoting new bone formation. Simon et al showed the delayed effects of fracture healing when animals were treated with COX-2 inhibitors.Gerstenfeld et al. studied the reversibility of COX-2 inhibition on the short term bone healing in an animal model. They found that COX-2 inhibitors block fracture healing more than NSAIDS and the magnitude of this effect is related to the duration of treatment.While specific inhibitors of COX-2 exist, traditionalNSAIDs non-specifically inhibit both COX-1 and COX-2 enzymes. In addition to its role in inflammation, COX-2 has been shown to be upregulated in many human cancers such as gallbladder carcinoma.A 60-year-old man has had intermittent pain in his right great toe for the past 2 years. What is the most likely cause for the lesions shown in Figure A?Monosodium urate crystal depositionCalcium pyrophosphate depositionRenal osteodystrophyTuberculosisSarcoidosisGout is a disorder of nucleic acid metabolism that leads to monosodium urate crystal deposition in the joints. The most common area of the body to be affected by gout is the first toe. The radiograph in Figure A demonstrates joint space narrowing of the 1stmetarsalphalangeal joint and the arrows show medial soft tissue swelling at the 1st MTP with soft tissue radio-densities and some erosive changes consistent with gout.Weinfeld et al report their experience over a 7 year period with hallux MTP arthritis in 439 patients they treated. Surgical indications included pain, shoewear problems, and failure of non-operative management.Reber et al describe a rare case of tophaceous gout in the medial sesamoid of the hallux and review the diagnosis, pathophysiology, and suggested management.Eggebeen reports "gout is caused by monosodium urate crystal deposition in tissues leading to arthritis, soft tissue masses (i.e., tophi), nephrolithiasis, and urate nephropathy. The biologic precursor to gout is elevated serum uric acid levels (i.e., hyperuricemia). The diagnosis is confirmed if monosodium urate crystals are present in synovial fluid."Incorrect Answers:Which of the following pharmacologic agents is associated with the highest risk of bleeding and thrombocytopenia?CoumadinEnoxaparinUnfractionated heparinDalteparinProtamine sulfateOf the options listed unfractionated heparin is associated with the highest rate of bleeding and thrombocytopenia. This may occur as part of a syndrome called Heparin Induced Thrombocytopenia (HIT).Unfractionated heparin works in the coagulation cascade by binding and enhancing the ability of antithrombin III to inhibit factors IIa, III, Xa. A known complication of unfractionated heparin use is Heparin Induced Thrombocytopenia (HIT). Heparin Induced Thrombocytopenia (HIT) is caused by the formation of abnormal antibodies that activate platelets leading to abnormal formation of blood clots inside a blood vessel, leading tobleeding and thrombocytopenia.Dorr et al. reviewed multimodal thromboprophylaxis for total hip and knee arthroplasty based on risk assessment in 1179 patients. They recommend careful use and monitoring of thromboprophylaxis after arthroplasty procedures to protect patients from thromboembolic events while also limiting adverse clinical outcomes secondary to thromboembolic, vascular, and bleeding complications.Mont et al. performed a study on preventing venous thromboembolic disease in patients undergoing elective hip and knee arthroplasty. They recommended all patients do early mobilization and receive pharmacologic prophylaxis and mechanical compressive devices for the prevention of thromboembolic disease. The group did not recommend any specific pharmacologic agents and/or mechanical devices.Illustration A shows a figure of the coagulation cascade and the target molecule of both unfractionated heparin and low molecular weight heparin.Incorrect Answers:Which of the following series of lab values is most consistent with a diagnosis of high turnover renal osteodystrophy?Decreased calcium, increased serum phosphate, increased alkaline phosphatase, increased parathyroid hormoneDecreased calcium, decreased serum phosphate, increased alkaline phosphatase, increased parathyroid hormoneIncreased calcium, normal serum phosphate, increased alkalinephosphatase, normal parathyroid hormoneDecreased calcium, increased serum phosphate, normal alkaline phosphatase, decreased parathyroid hormoneIncreased calcium, normal serum phosphate, normal or high alkaline phosphatase, increased parathyroid hormoneDecreased calcium, increased serum phosphate, increased alkaline phosphatase, and increased parathyroid hormone are all characteristic of renal osteodystrophy.Renal osteodystrophy represents a spectrum of disease seen in patients with chronic renal disease. It is characterized by bone mineralization deficiency due to electrolyte and endocrine abnormalities. High turnover renal osteodystrophy is classically associated with significantly increased phosphate and parathyroid hormone (PTH) levels. Chronic renal disease leads to a decrease in renal phosphorus excretion, which leads to phosphate retention and a significant increase in PTH levels. This ultimately can lead to tertiary hyperparathyroidism.Tejwani et al present a review article on renal osteodystrophy. They state that in high- turnover renal osteodystrophy PTH secretion is increased and, in the absence of medical intervention, leads to parathyroid gland hyperplasia. This hyperplasia is associated with loss of feedback inhibition in normal regulation of PTH secretion; consequently, even after correction of the renal disease, the parathyroid gland continues to secrete excessive levels of PTH.Illustration A shows a pathologic fracture secondary to renal osteodystrophy. Incorrect Answers:This series of lab values is consistent with a diagnosis of nutritional rickets due to vitamin D deficiency.This series of lab values is consistent with a diagnosis of low-turnover renal osteodystrophy. This is classically caused by excess deposition of aluminum into bone which impairs PTH release from the parathyroid gland and disrupts the mineralization process.This series of lab values is consistent with a diagnosis of hypoparathroidism. 5-This series of lab values is consisten with a diagnosis of primary hyperparathryoidism.A 28-year-old African-American male with a history of Sickle Cell Disease complains of progressive left hip pain for the past two years. He denies any causative injuries. His images are shown in Figures A and B. Which of the following mechanisms is most likely responsible for his symptoms?Blood disorder due to abnormal hemoglobin S allelesProgressive slippage of physis though the hypertrophic zoneOsteomyelitis most likely due to Salmonella speciesAccumulation of glycosaminoglycan breakdown productsCOL5A1 or COL5A2 mutationThe clinical presentation and images are most consistent with left hip osteonecrosis as a result of coagulation and vascular occlusion caused by sickle cell anemia.Sickle cell disease is a genetic disorder of hemoglobin synthesis characterized by 2 abnormal hemoglobin S alleles. Under low oxygen conditions the affected blood cells become "sickle shaped" and unable to pass through vessels. This results in vascular occlusion that may have a variety of clinical consequences depending on the body part affected.Hernigou et al. review the natural history of symptomatic osteonecrosis in adults with sickle cell disease. Once symptomatic , osteonecrosis of the hip in sickle cell disease has a high likelihood of progressing and leading to femoral head collapse. Deterioration can be rapid and in most patients operative intervention is necessary to prevent further collapse or alleviate intractable pain.Mont et al. performed a literature review on the natural history of untreated asymptomatic osteonecrosis of the femoral head. Their findings supported that asymptomatic osteonecrosis had a high prevalence of progression to symptomatic femoral head collapse. Small, medially located lesions had a low rate of progression, while medium to large sized osteonecrotic lesions did progress in a substantial number of patients. They recommendedconsideration of joint-preserving surgical treatment in asymptomatic patients with a medium-sized or large, laterally located lesion.Figure A shows an AP pelvis with left hip osteonecrosis. Figure B shows a T2 coronal MRI with left hip osteonecrosis. Illustration A shows an example of a hemoglobin molecule which has become "sickle shaped," and as a result is unable to pass through vessels efficiently.Incorrect Answers:slipped capital femoral epiphysis.What mechanism allows Staphylococcus epidermidis to adhere to surfaces and resist phagocytosis?Creation of active efflux pumpsMethylation of 23s rRNABiofilm productionAlteration of cell wall permeabilityBeta-lactamase productionStaphylococcus epidermidis is a gram-positive bacteria that utilizes a glycocalyx/biofilm to adhere to orthopedic implants and other surfaces and resist phagocytosis.The biofilm creates a well-protected environment where bacteria can proliferate and thrive essentially undetected by the host immune system. This leads to chronic infections of orthopedic implants that can go undetected for years.Arciola et al note that S. epidermidis can colonize surfaces in a self-generated viscous biofilm composed of polysaccharides and that the ica genes found in56% of S. epidermidis isolates were associated with their ability to produce biofilm.Olson et al discuss the importance of polysaccharide intercellular adhesin (PIA), asubstance produced by 50-60% of S. epidermidis strains, in the adherence of S. epidermidis to biomaterials through biofilm creation. PIA plays a critical role in initial adherence of S. epidermidis to biomaterials, biofilmmaturation and aggregation.Illustration A shows microscopy of Staphylococcus epidermidis, which is a gram- positive, coagulase-negative cocci. Illustration B is an overview of the different classes of organisms in microbiology.Incorrect Answers:Compared to cold-forged cobalt chrome, titanium alloys have which property?Increased fatigue strengthIncreased yield strengthIncreased endurance limitDecreased ductilityDecreased tensile strengthTitanium implants have decreased tensile (ultimate) strength when compared to cobalt chrome.Ultimate strength, or tensile strength, is the maximum stress a material can withstand before undergoing breakage or failure. The ranking of ultimate strength, from highest to lowest is: 1) cobalt chrome, 2)titanium, 3)stainless steel, and 4) cortical bone.Young's modulus of elasticity is defined as the measure of stiffness of a material in the elastic zone. A higher Young's modulus indicates a stiffer material. While titanium is highly biocompatible with a low modulus of elasticity (Young's modulus), it has poor wear characteristics making it non- suitable for femoral heads in total hip arthroplasty.Long et al. present a review on titanium implants with a focus on bio- mechanical properties. Their study supports previous data which showed high rates of ultra-high molecular weight polyethylene wear due to accelerated breakdown when in contact with a titanium surface.Incorrect Answers:Peak bone mass attainment in both men and women is most dependent on which sex-steroid?TestosteroneProgesteroneGrowth HormoneEstrogenCortisolEstrogen has been shown to be important for both men and women in attaining peak bone mass.Risk factors for osteoporosis are: increasing age, female sex, early menopause, fair-skinned, family history of hip fracture, low body weight, smoking, glucocorticoid use, excessive alcohol, low protein intake, and anticonvulsant or antidepressant use.Which of the following contributes most to the ability of hyaline cartilage to attract water?AggrecanBiglycanDecorinFibromodulinOsteocalcinAggrecan molecules bind to hyaluronic acid molecules via link proteins to form a macromolecule complex, known as a proteoglycan aggregate, which attracts water.Proteoglycans are composed of subunits known as glycosaminoglycans. Glycosaminoglycans include two subtypes: chondroitin sulfate and keratin sulfate. These glycosaminoglycans link to a protein core by sugar bonds to form an aggrecan molecule. Link proteins then stabilize many of these aggrecan molecules to hyaluronic acid to form the proteoglycan aggregate. Cartilage also contains ancillary proteoglycans that are much smaller than the aggregating proteoglycans. These small proteoglycans include decorin, biglycan, and fibromodulin. They bind to other molecules (eg, type II collagen) and assist in matrix stabilization.Ulrich-Vinther et al. authored a Level 5 review on cartilage structure. The negative charge present within the hyaline cartilage extracellular matrix attracts cations and results in an increase in tissue osmolality. This then attracts water, which decreases the osmolality. Thus, articular cartilage has a high tissue pressure, but the presence of type II collagen matrix prevents it from swelling.Nap et al. present a basic science review article on aggrecans. They discus that the main function of aggrecan in cartilage is to resist compressive forces.They note that the negative charge of the aggrecan molecule disaccharides create the high osmotic swelling pressure of cartilage.Illustration A depicts the molecular organization of an aggregated proteoglycan molecule. Incorrect Answers:What effect do bisphosphonate medications have on spinal fusion surgery when taken in the postoperative period?Any effect can be counteracted by taking calcium supplementsNo effectIncreased risk of wound infectionSmaller fusion massDecreased fusion rateBisphosphonates (e.g. alendronate) are used to treat osteoporosis. The mechanism of action is inhibiting the formation of the ruffled border of osteoclasts, resulting in decreasing bone turnover.Huang et al performed a rat study comparing alendronate to placebo and found that fusion rates were lower in those treated with alendronate. However,the fusion masses were larger in the alendronate treated rats despite lower fusion rates (why #4 is incorrect).Lehman et al in another placebo controlled rate study found that the fusion rates for placebo (76%) were greater than the alendronate group (45%). Alendronate works on osteoclasts and does not affect calcium directly. Taking calcium should have no effect on alendronate (why #1 is incorrect). At this time there are no formal recommendations of when to stop bisphosphonate medication prior to spinal fusion surgery.A therapeutic study presents a systematic review of 15 high- quality randomized controlled trials with homogeneous results. What level of evidence is this considered?IIIIIIIVVA systematic review of high-quality clinical trials is considered a Level I study.A systematic review is a powerful tool used to identify, evaluate and appraise all high- quality research related to a specific question. Systematic reviews, in contrast to most narrative review articles, adhere to strict scientific design by following eight steps; 1) defining a question and developing inclusion criteria,

DISCUSSION: Contact between metals in a biologic environment leads to galvanic corrosion. Reduction potentials of Co-Cr and stainless steel produce the worst combination of metals in commonly used implants. Because the fixation implants are not intended to contact the existing implant, it is not as great a consideration as the plate and the screws and cables that will directly contact each other.

Although the early use of FDS as a transfer to restore finger extension in patients with radial nerve palsy was performed by passing the tendon through the interosseous membrane, Nalebuff and Patel later modified this procedure for the rheumatoid arthritis patient by passing the FDS radially, around the radius in a dorsal direction. They felt that this provided a number of advantages, including: 1. technical ease, 2. avoidance of synovial disease on the dorsum of the wrist, and 3. correction of ulnar deviation of the fingers through the line of pull from the radial side of the forearm.

Several cancers directly produce receptor activator of nuclear factor kappa beta ligand (RANKL) which leads to bone resorption and the lytic lesions seen on radiographs.Cancers that originate or metastasize to bone can be blastic, lytic, or mixed when viewed on radiographs. Lytic lesions appear radiolucent due to bone resorption that occurs around the cancer cells. This is secondary to direct production and release of RANKL by the cancer cells themselves. RANKL then stimulates osteoclastogenesis and an increase in local bone resorption. Denosumab is a monoclonal antibody against RANKL that has been shown to decrease rates of pathologic fractures.Lynch et al. review the progression of metastatic disease. They note that cancer cells can stimulate both osteogenesis and osteolysis, and that this pathologic increase in bone matrix turnover is what allows the cancer to progressively expand or metastasize to distant sites. They discuss the role of matrix metalloproteinases as primary regulators of this process.Illustration A is a diagram illustrating how the binding of RANKL to receptors on the surface of osteoclast precursors activates them and begins the process of bone resorption. Cancer cells can directly produce RANKL thus increasing the rate of local bone resorption.Incorrect Answers:

Khan and associates in a retrospective review found that CRP was more responsive and normalized with resolution of infection, whereas the ESR can remain elevated in the presence of a normal CRP. Since the normal range of ESR and CRP usually begins at 0, a level that is below normal is not likely to be found.

Capsular exposure for an inside-out lateral meniscal repair is performed by developing the interval between the iliotibial band and biceps tendon. Posterior retraction of the biceps tendon exposes the lateral head of the gastrocnemius. Posterior retraction of the gastrocnemius provides access to the posterolateral capsule.

DISCUSSION: The collagen orientation changes from parallel in the superficial zone to a more random pattern in the middle zone and finally to perpendicular in the calcified zone. REFERENCES: Koval KJ (ed): Orthopaedic Knowledge Update 7. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 498-499. Mankin HJ, Mow VC, Buckwalter JA: Articular cartilage structure, composition, and function, in Einhorn TA, O’Keefe RJ, Buckwalter JA (eds): Orthopaedic Basic Science: Foundations of Clinical Practice, ed 3. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2006, in press.

The Physician Payments Sunshine Act requires all payments by corporations to physicians beyond $10 per year to be reported to the Centers for Medicare and Medicaid Services.Under this Act, all manufacturers of drugs and devices covered under Medicare, Medicaid, and SCHIP are obliged to federally report payments beyond $10 annually to physicians and academic centers. The Act was first introduced in 2007, enacted in 2010, and in 2014 the first data (from 2012) was reported publicly online in the Open Payment Program of the Centers for Medicare and Medicaid Services website.Samuel et al analyze orthopedic surgeons available data from the Sunshine Act regarding industry payments and find over 110 million USD paid to approximately 15,000 orthopedic surgeons over the 5-month study period. No long term data exists to determine if these payments have any affect in healthcare.Incorrect Answers:

DISCUSSION: The meniscal cartilage, like articular cartilage, possesses viscoelastic properties. The extracellular matrix is a biphasic structure composed of a solid phase (collagen, proteoglycan) that acts as a fiber-reinforced porous-permeable composite, and a fluid phase that may be forced through the solid matrix by a hydraulic pressure gradient. Although these properties are shared with articular cartilage, the meniscus is more elastic and less permeable than articular cartilage. REFERENCES: Beaty JH (ed): Orthopaedic Knowledge Update 6. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 3-23. Arendt EA (ed): Orthopaedic Knowledge Update: Sports Medicine 2. Rosemont, IL, AAOS, 1999, pp 349-354.

DISCUSSION: Local control of recurrent diffuse PVNS is best accomplished with open arthrotomy and complete synovectomy. Arthroscopic methods in the setting of persistent diffuse PVNS are associated with an unacceptably high rate of recurrence. Radiation therapy (700 cGy) is the typical dose administered for heterotopic ossification prophylaxis, but this dose is not high enough to achieve local control in PVNS. Imatinib, a colony-stimulating factor inhibitor, has been described for recurrent/refractory disease, but is not considered as effective as open surgical treatment.

DISCUSSION: The risk of Salmonella osteomyelitis is much greater in patients with sickle cell disease than the general population. The exact reason for this increased risk is still unclear, but it appears to be associated with an increased incidence of gastrointestinal microinfarcts and abscesses. Both Staphylococcus aureus and Salmonella have been mentioned as the most prevalent causative organisms. REFERENCES: Piehl FC, David RJ, Prugh SI: Osteomyelitis in sickle cell disease. J Pediatr Orthop 1993;13:225-227. Givner LB, Luddy RE, Schwartz AD: Etiology of osteomyelitis in patients with major sickle hemoglobinopathies. J Pediatr 1981;99:411-413. Epps CH Jr, Bryant DD III, Coles MJ, Castro O: Osteomyelitis in patients who have sickle-cell disease: Diagnosis and management. J Bone Joint Surg Am 1991;73:1281-1294. Lovell and Winter’s Pediatric Orthopaedics, ed 4, 1996.

DISCUSSION: The best method of preventing wrong-site surgery is for the surgeon to initial the surgical site in the preoperative holding area after discussion and confirmation of the site with the patient. This should be done before sedating medications are administered. A recent study found that patient noncompliance with specific preoperative instructions to mark the site with a “yes” at home was surprisingly high; only 59% of the patients marked the extremity correctly and 37% made no mark. Noncompliance was higher in those with workers’ compensation claims (70%) and those with previous related surgery (51%).

Chronic Vitamin D deficiency leads to problems with bone health and has been shown to increase the risk of falls in the elderly. Appropriate supplementation of Vitamin D has been shown to decrease this risk. Conversion in the skin decreases with age and may be nearly nonexistent in darkly pigmented individuals. Vitamin D3 is the preferred form for supplementation, but D2 is the form most available by prescription in the US. Hypervitaminosis D is rare and very high doses can be tolerated without significant concern for toxicity. Because the patient has sustained one insufficiency fracture, she is at risk for insufficiency fractures in other skeletal locations, rendering expectant observation insufficient. Her serum calcium is normal, and with a low Vitamin D level, calcium utilization in her system would be inadequate. Bisphosphonate therapy in addition to calcium and vitamin D supplementation may provide a good long-term solution, but should not be instituted until the bone mineral imbalance has been adequately corrected. Surgical fixation of this fracture is not indicated, particularly in lieu of improving symptoms.

Patients who have skin and soft-tissue infections caused by CA-MRSA often describe the lesion as a spider bite. The cytotoxin Panton-Valentine leukocidin that is produced by many strains of CA-MRSA causes tissue necrosis, resulting in rapid development of an abscess and the appearance of a spider bite. Patients with psoriasis have thick, red skin with flaky, silver-white patches. Tinea corporis is a general term for a cutaneous fungal infection. The lesion appears as a well-demarcated erythematous plaque with a raised border and central hypopigmentation, giving it a ring-like appearance. Primary infection with herpes simplex virus can produce constitutional symptoms with burning, tingling, or stinging at the site. Grouped vesicles with clear fluid 1 to 2 mm in size form on an erythematous base and then rupture, leaving moist ulcers or crusted plaques.(SBQ07SM.48) Carbohydrate loading is a common practice among endurance athletes that works by what mechanism?Review TopicIncreasing serum fructose levelsMaximizing stored muscle glycogen for endurance after 90 minutes of exerciseDiuresisDecreasing serum glucose levelsMaximizing stored liver glycogen for endurance after 60 minutes of exerciseCarbohydrate loading is a strategy that involves changes to training and nutrition which can maximize muscle glycogen stores prior to endurance exercise lasting longer than 90 minutes.There continues to be varying scientific opinions as to whether athletes should eat low vs. high glycemic index foods, and how this will affect the amount that the serum glucose levels rise. Fructose is able to be converted to glycogen in the liver but not muscle, therefore high-fructose containing foods are suboptimal. This practice is recommended for athletes participating in events that are longer than 90 minutes (after the bodies normal supply of glycogen is depleted).Coyle et al. analyzed 10 trained cyclists who performed two bicycle ergometer exercise tests 1 wk apart. They found that blood glucose concentration was 20-40% higher during the exercise after carbohydrate ingestion than during the exercise without carbohydrate feeding. The exercise-induced decrease in plasma insulin was prevented by carbohydrate feeding. Ultimately, fatigue was postponed by carbohydrate feeding during exercise in seven out of the ten subjects.Costill et al. examined the effect of carbohydrates on muscle glycogen resynthesis in trained runners and found that muscle glycogen levels could be normalized with the proper use of carbohydrates after strenuous activity.Sherman et al. used muscle biopsies to determine the effects of moderate- or high-carbohydrate diets on muscle glycogen and performance in runners and cyclists over 7 consecutive days of training. They found that a high carbohydrate diet restored muscle glycogen to more normal levels than a moderate carbohydrate diet but did not find any difference in the effect on performance.Illustration A is a graph depicting the typical carbohydrate depletion/loading regimen that endurance athletes utilize to maximize muscle glycogen stores prior to endurance exercise. This typically involves a hard workout followed by three days of a low-carb diet, another hard workout, and another three days of a high-carb diet.Incorrect

The only factor that is prognostic for outcomes is the quality of the reduction. None of the other factors has any effect on the outcome. Early range of motion or physical therapy may offer temporary effects, but these small advantages do not last beyond 3 months after surgery.

Smith looked at 12 pts (7 pts with DM) with a large ulcer and osteomyelitis of the calcaneus all treated with a partial calcanectomy. All pts had an ABI >.45, Transcutaneous P02 > 28mmHg, Albumin level > 3.0 and WBC > 1500. 10 of 12 healed and retained mobility. A total contact cast could be used in a pt with adequate blood flow, and no osteomyelitis A syme's amputation(through ankle) requires the use of a healthy plantar soft tissue flap for coverage . A transtibial (BKA) amputation would be the choice for a failed partial calcanectomy or in a patient who had an ABI < .45 and who wasn't a candidate for a revasculization procedure. Nonweightbearing and IV antibiotics would not be adequate in a diabetic pt with osteo of this extent.