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1. General Principles & Basic Science MCQs

Practice Set 223 of 789

This practice set contains high-yield board review questions covering key concepts in 1. General Principles & Basic Science. Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 4441

Topic: 1. General Principles & Basic Science

Figure 11 shows the radiograph of a 26-year-old man with type I diabetes mellitus who was struck by a motor vehicle. What is the most common complication associated with this pelvic fracture?

Trauma 2009 Practice Questions: Set 1 (Solved) - Figure 30

. Infection
. Sciatic nerve palsy
. Heterotopic ossification
. Deep venous thrombosis
. Degenerative arthritis

Correct Answer & Explanation

. Deep venous thrombosis

Explanation

The most common complication following acetabular or pelvic ring injury is deep venous thrombosis (DVT). Without prophylaxis, rates of DVT are as high as 70% to 80%. With prophylaxis, the rates are around 10%. Infection rates in surgical repair of acetabular fractures are relatively low but a history of diabetes mellitus and a significant Morel-Lavalle lesion certainly increase the risk. However, even with these two complicating factors, the rates of infection are still lower than 10%. Sciatic nerve palsy rates from the injury alone approach 20% and iatrogenic injury is usually less than 2%. Degenerative changes to the hip following this injury approach 20% to 25%, even with an anatomic reduction. Geerts WH, Code KI, Jay RM, et al: A prospective study of venous thromboembolism after major trauma. N Engl J Med 1994;331:1601-1606.

Question 4442

Topic: Infection, Pharmacology & VTE

A 42-year-old woman underwent an instrumented posterior spinal fusion at L3-S1 with transforaminal lumbar interbody fusion. She had an excellent clinical result with complete resolution of leg pain. Three months later she now reports increasing back pain and weakness in her legs. Examination reveals weakness in the quadriceps and tibialis anterior. Radiographs show no interval changes in the position of the hardware. MRI scans are shown in Figures 2a through 2c. What is the next most appropriate step in management?

. Observation
. Oral antibiotics only
. IV antibiotics only
. Irrigation and debridement of the surgical site
. Irrigation and debridement of the surgical site with hardware removal

Correct Answer & Explanation

. Irrigation and debridement of the surgical site

Explanation

The MRI scans reveal a postoperative infection. Observation and antibiotics are not appropriate choices. There is a large fluid collection and this requires decompression because the patient has neurologic changes. There is considerable debate regarding the removal of hardware. Many contend that biofilm on the implants can harbor the infection. However, these complications usually can be treated with serial irrigations, debridements, and IV antibiotics. The incidence of infection has been widely studied with varying rates in fusions with instrumentation. Rates appear to be increased with instrumentation, yet these infections usually can be managed without hardware removal. Glassman SD, Dimar JR, Puno RM, et al: Salvage of instrumental lumbar fusions complicated by surgical wound infection. Spine 1996;21:2163-2169.

Question 4443

Topic: Biology, Genetics & Bone Healing

It has been shown that bisphosphonate-based supportive therapy (pamidronate or zoledronate) reduces skeletal events (onset or progression of osteolytic lesions) both in patients with multiple myeloma and in cancer patients with bone metastasis. The use of biphosphonate therapy has been associated with

Basic Science 2008 Practice Questions: Set 1 (Solved) - Figure 61

. increased medical complications of treatment.
. osteonecrosis of the jaw.
. improved long-term survival rates.
. anorexia.
. decreased quality of life measures.

Correct Answer & Explanation

. osteonecrosis of the jaw.

Explanation

The use of bisphosphonates has been recently associated with the development of osteonecrosis of the jaw. Length of exposure seems to be the most important risk factor for this complication. The type of bisphosphonate may play a role and previous dental procedures may be a precipitating factor. Bisphosphonates are a class of therapeutic agents originally designed to treat loss of bone density (ie, alendronate). The primary mechanism of action of these drugs is inhibition of osteoclastic activity, and it has been shown that these drugs are useful in diseases with propensities toward osseous metastases. In particular, they are effective in diseases in which there is clear upregulation of osteoclastic or osteolytic activity, such as breast cancer and multiple myeloma, and have developed into a mainstay of treatment for individuals with these diseases. Although shown to reduce skeletal events, there has been no improvement in patient survival. Bamias A, Kastritis E, Bamia C, et al: Osteonecrosis of the jaw in cancer after treatment with bisphosphonates: Incidence and risk factors. J Clin Oncol 2005;23:8580-8587. Thakkar SG, Isada C, Smith J, et al: Jaw complications associated with bisphosphonate use in patients with plasma cell dyscrasias. Med Oncol 2006;23:51-56.

Question 4444

Topic: Infection, Pharmacology & VTE

An 8-year-old boy has had pain and swelling around the right knee for the past 4 weeks. He recalls bumping it about 4 weeks ago. He has no pain in other joints, and denies any fevers, chills, or other symptoms. A radiograph is shown in Figure 13. Laboratory studies show a WBC count of 9,700/mm3, an erythrocyte sedimentation rate of 18 mm/h, and a C-reactive protein level of 3.7 mg/L. What is the next most appropriate step in management?

Pediatrics Board Review 2007: High-Yield MCQs (Set 2) - Figure 3

. Chemotherapy and radiation therapy
. Intravenous antibiotics, protected weight bearing, and a repeat C-reactive protein after improvement
. Open biopsy and debridement of the site, followed by intravenous antibiotics
. Technetium Tc 99m bone scan
. Empiric oral antibiotics and repeat laboratory studies in 1 week

Correct Answer & Explanation

. Open biopsy and debridement of the site, followed by intravenous antibiotics

Explanation

The history and laboratory findings are consistent with osteomyelitis of the patella. The radiograph reveals bone destruction in the patella; therefore, the next most appropriate step is open biopsy and debridement of the site. Aspiration of the knee joint may be needed to rule out septic arthritis prior to patellar debridement. With this amount of bone destruction, surgical debridement is helpful to obtain cultures and to remove necrotic material. Administering antibiotics without any prior culture increases the risk of negative cultures later and a potentially incorrect choice of antibiotic. A neoplasm should be included in the differential. It would be inappropriate to initiate chemotherapy and radiation therapy without a biopsy-confirmed diagnosis. A bone scan is likely to demonstrate uptake, but radiographs have already localized the abnormality to the patella. Morrisy RT: Bone and joint sepsis, in Morrissy RT, Weinstein SL (eds): Lovell and Winter's Pediatric Orthopaedics, ed 5. Philadelphia, PA, Lippincott Williams & Wilkins, 2001, pp 466-470.

Question 4445

Topic: Biomechanics & Biomaterials

The load versus deformation curve of the functional spinal unit (FSU) is made up of the neutral zone, the elastic zone, and the plastic zone. What is the plastic zone of the curve believed to represent?

. Lining up of collagen fibers within the ligaments
. Stretching of elastin within the disk and ligaments
. Transition between flexion and extension
. Reversible elongation of the soft tissues
. Traumatic range of motion, resulting in damage to the soft tissues

Correct Answer & Explanation

. Traumatic range of motion, resulting in damage to the soft tissues

Explanation

Plastic deformation of viscoelastic tissues represents deformation of the soft tissues to the point of failure. The lining up of collagen fibers would be in the "toe region" of the curve, which, in the case of the FSU, would be mainly in the neutral zone. Elastin is a minor contributor to the composition of the ligaments and would be protected by the stiffer collagen fibers. The transition between flexion and extension occurs in the neutral zone, and reversible elongation occurs in the elastic zone. Fardon DF, Garfin SR, Abitbol J, et al (eds): Orthopaedic Knowledge Update: Spine 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 15-23.

Question 4446

Topic: Surgical Anatomy & Approaches

A 72-year-old woman who sustained a cerebrovascular accident 9 months ago now has a fixed elbow flexion contracture of 80 degrees. Management should consist of

Upper Extremity 2005 Practice Questions: Set 1 (Solved) - Figure 10

. passive physical therapy.
. musculocutaneous neurectomy and serial casting.
. musculocutaneous nerve block.
. lengthening of the biceps tendon.
. distraction arthroplasty.

Correct Answer & Explanation

. musculocutaneous neurectomy and serial casting.

Explanation

A flexion contracture of the elbow is commonly seen in hemiplegic patients following cerebrovascular accidents. Spasticity and myostatic contracture of the joint are both causative factors. In patients with a flexion deformity of less than 90 degrees, musculocutaneous neurectomy is recommended, followed by serial casting to treat any residual deformity. At 9 months after injury, physical therapy will not significantly improve motion. Nerve blocks may be used in the early stages of recovery to facilitate therapy and serial casting.

Question 4447

Topic: Infection, Pharmacology & VTE

A 7-year-old boy has had low back pain for the past 3 weeks. Radiographs reveal apparent disk space narrowing at L4-5. The patient is afebrile. Laboratory studies show a WBC count of 9,000/mm3 and a C-reactive protein level of 10 mg/L. A lumbar MRI scan confirms the loss of disk height at L4-5 and reveals a small perivertebral abscess at that level. To achieve the most rapid improvement and to lessen the chances of recurrence, management should consist of

. oral antibiotics.
. IV antibiotics.
. surgical drainage of the perivertebral abscess and IV antibiotics.
. bed rest.
. cast immobilization.

Correct Answer & Explanation

. IV antibiotics.

Explanation

The patient has diskitis. Administration of IV antibiotics speeds resolution and minimizes recurrence. Bed rest and cast immobilization have been successfully used to treat this disorder but can be associated with prolonged recovery and frequent recurrence, even when oral antibiotics are administered. A perivertebral abscess seen in association with this condition usually resolves without surgery. Ring D, Johnston CE II, Wenger DR: Pyogenic infectious spondylitis in children: The convergence of discitis and vertebral osteomyelitis. J Pediatr Orthop 1995;15:652-660.

Question 4448

Topic: Physiology & Rehabilitation

A 10-year-old boy with spastic diplegic cerebral palsy walks in a crouched position with the hips and knees flexed. Maximum knee flexion is 15 degrees during early swing phase. Instrumented gait analysis shows quadriceps activity from terminal stance throughout swing phase. Treatment should consist of

. proximal release of the proximal tendon of the rectus femoris.
. release of the distal tendon of the rectus femoris.
. transfer of the distal rectus femoris tendon.
. V-Y lengthening of the quadriceps tendon.
. Z lengthening of the patellar tendon.

Correct Answer & Explanation

. transfer of the distal rectus femoris tendon.

Explanation

The rectus femoris muscle spans two joints and is active during running, sprinting, and walking at a fast pace during the preswing and early swing phase of gait. In these situations, the muscle helps to generate power to initiate hip flexion while absorbing or controlling the rate of knee flexion during early swing phase. Quadriceps activity, including the rectus femoris, is not normally needed when walking at a routine cadence. However, rectus femoris activity is commonly noted during preswing and the swing phase in patients with cerebral palsy, particularly those with diplegia. In an effort to initiate swing phase, the rectus femoris is "overactive." As a result, the knee flexion that commonly occurs at terminal stance and initial swing is restricted. Instead of achieving the normal 50 to 60 degrees of flexion during early swing, this patient's knee flexion is limited to 15 degrees. The goal of treatment is to retain rectus femoris activity for initiation of hip flexion but to diminish its restraint on knee flexion. Studies have shown that transfer of the distal rectus femoris tendon provides more flexion of the knee during the swing phase of gait than simply releasing the tendon. V-Y lengthening of the quadriceps tendon or a Z lengthening of the patellar tendon causes too much weakening of the quadriceps muscle and worsens the crouch deformity. In addition to transfer of the rectus femoris tendon, other procedures are often done concomitantly to obtain the best balance and realignment of hip-knee-ankle activity. Aiona MD: Guidelines for managing lower extremity problems in cerebral palsy, in Fitzgerald RH, Kaufer H, Malkani AL (eds): Orthopaedics. St Louis, MO, Mosby, 2002, pp 1534-1541. Chambers H, Laure A, Kaufman K, Cardelia M, Sutherland D: Prediction of outcome after rectus femoris surgery in cerebral palsy: The role of cocontraction of the rectus femoris and vastus lateralis. J Pediatr Orthop 1998;18:703-711.

Question 4449

Topic: Biology, Genetics & Bone Healing

Figure 11a shows the AP pelvis radiograph of a 25-year-old man who sustained a spinal cord injury 10 years ago. A bone scan and a CT scan are shown in Figures 11b and 11c. To prevent recurrence after resection, management should consist of

. radiation therapy.
. bisphosphonate therapy.
. antitubercular therapy.
. parathyroidectomy.
. a diet low in phosphate.

Correct Answer & Explanation

. radiation therapy.

Explanation

The studies reveal significant heterotopic ossification that appears to be mature. Following resection, the most reliable way to prevent recurrence is with low-dose external-beam radiation therapy. Bisphosphonate therapy can be considered; however, when terminated, heterotopic bone may reform. Heterotopic ossification is unrelated to the patient's endocrine status and is not associated with any metabolic abnormalities. Moore K, Goss K, Anglen J: Indomethacin versus radiation therapy for prophylaxis against heterotopic ossification in acetabular fracture. J Bone Joint Surg Br 1998;80:259.

Question 4450

Topic: 1. General Principles & Basic Science

Which of the following conditions precludes performing a tendon transfer?

. The target joint has a full passive range of motion.
. The range of motion of the target joint only occurs in the direction of correction.
. The target joint cannot be passively corrected to its neutral position.
. The muscle to be transferred is out-of-phase.
. There is no pulley to assist the transferred muscle's fulcrum.

Correct Answer & Explanation

. The target joint cannot be passively corrected to its neutral position.

Explanation

Several conditions must be met before a tendon transfer has the potential to correct a dynamic deformity. If the target joint cannot be passively corrected to neutral, it indicates that a static joint contracture or bony deformity exists that cannot be corrected with a dynamic tendon transfer. While in-phase muscles are best, out-of-phase muscles are often the only muscles available for transfer. Tendon transfer should pull in a straight line to avoid tethering and late failure. Canale ST (ed): Campbell's Operative Orthopaedics, ed 10. St Louis, MO, Mosby, 2003, pp 1283-1287.

Question 4451

Topic: Biology, Genetics & Bone Healing

A 72-year-old man has had persistent pain after undergoing a hemiarthroplasty 18 months ago. Radiographs are shown in Figures 50a and 50b. What is the most likely cause of his problem?

. Suboptimal cement technique
. Excessive activity level
. Oversized bipolar component
. Infection
. Osteoporosis

Correct Answer & Explanation

. Infection

Explanation

The radiographs demonstrate a rapid erosion of the bipolar component into the acetabulum. Although acetabular erosion is more common with unipolar hip arthroplasties, it can occur with bipolar components. Haidukewych and associates noted a very low erosion rate but none in the first 2 years. The second finding on the radiographs is the linear radiolucency progressing from the joint toward the end of the stem at the cement-bone interface suggesting chronic infection or diffuse loosening. The persistent pain since implantation also suggests chronic infection. High activity levels and osteoporosis do not lead to acetabular erosion in the first 2 years after hemiarthroplasty. While the cement technique is suboptimal, loosening and erosion should not be expected from this alone. An oversized bipolar head would extrude and not erode. Haidukewych GJ, Israel TA, Berry DJ: Long-term survivorship of cemented bipolar hemiarthroplasty for fracture of the femoral neck. Clin Orthop Relat Res 2002;403:118-126. Lestrange NR: Bipolar hemiarthroplasty for 496 hip fractures. Clin Orthop Relat Res 1990;251:7-19.

Question 4452

Topic: 1. General Principles & Basic Science

A study is designed that examines fractures in children with osteogenesis imperfecta after being treated with bisphosphonates compared with a placebo. A difference is found for which the P value is greater than what is considered to be statistically significant. What is the next appropriate statistical analysis?

. Repeated measures analysis of variance
. F test
. Power analysis
. Analysis of variance
. Kruskal-Wallis test

Correct Answer & Explanation

. Power analysis

Explanation

When a study yields a negative result between treatment groups, the next step is to perform a power analysis. The power, by definition, is the probability of rejecting the null hypothesis: in this example the null hypothesis would be that children treated with bisphosphonates would have fewer fractures than the untreated control population. The power analysis helps answer the question as to whether the null hypothesis should be rejected and the finding is real, or whether the sample size was too small or the effect of treatment too subtle to demonstrate a difference between the treatment and control groups. Buckwalter JA, Einhorn TA, Simon SR (eds): Orthopaedic Basic Science: Biology and Biomechanics of the Musculoskeletal System, ed 2. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2000, p 7.

Question 4453

Topic: 1. General Principles & Basic Science

Which of the following is considered the best method for the prevention of wrong-site surgery?

. The surgeon should check the consent form for the site and the procedure to be performed.
. The surgeon should ask the circulating nurse in the operating room.
. The patient should write "yes" on the surgical site at home with a permanent marker.
. The surgeon should initial the surgical site after discussion with the patient.
. The surgeon should check the operating room schedule.

Correct Answer & Explanation

. The surgeon should initial the surgical site after discussion with the patient.

Explanation

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%). DeGiovanni CW, Kang L, Manuel J: Patient compliance in avoiding wrong site surgery. J Bone Joint Surg Am 2003;85:815-819.

Question 4454

Topic: 1. General Principles & Basic Science

An 18-year-old man has acute respiratory distress after sustaining injuries in a motorcycle accident. He has a blood pressure of 80/60 mm Hg and a pulse rate of 110/min. Examination reveals chest tympany to percussion, distended neck veins, and deviation of the trachea away from his right hemithorax where the breath sounds are diminished. Heart sounds are regular and normal on auscultation. Initial management should consist of

Trauma Board Review 2000: High-Yield MCQs (Set 2) - Figure 20

. administration of 2 L of saline solution.
. subxiphoid pericardial aspiration.
. rapid infusion of 500 mL of colloid solution.
. insertion of a large-bore needle in the right third or fourth intercostal space.
. intubation followed by mechanical ventilation.

Correct Answer & Explanation

. insertion of a large-bore needle in the right third or fourth intercostal space.

Explanation

Tension pneumothorax occurs when air trapped in the pleural space between the lung and chest wall achieves sufficient pressure to compress the lungs and shift the mediastinum. Urgent needle decompression of the pleural space air followed by definitive chest tube placement is the treatment of choice.

Question 4455

Topic: Biomechanics & Biomaterials

A patient with a cobalt-chromium alloy (Co-Cr) femoral stem has a periprosthetic fracture that is to be fixed with a cable-plate device. The surgeon should make sure that the plate, screws, and cable, respectively, are made of

. Co-Cr, stainless steel, stainless steel.
. stainless steel, stainless steel, Co-Cr.
. stainless steel, Co-Cr, Co-Cr.
. titanium alloy, titanium alloy, titanium alloy.
. titanium alloy, stainless steel, Co-Cr.

Correct Answer & Explanation

. stainless steel, Co-Cr, Co-Cr.

Explanation

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. Miller MD (ed): Review of Orthopaedics, ed 3. Philadelphia, PA, WB Saunders, 2000, pp 119-144.

Question 4456

Topic: Biology, Genetics & Bone Healing

A 74-year-old man reports progressive left hip pain with weight-bearing activities. A radiograph is shown in Figure 30. What is the most likely underlying diagnosis?

Anatomy Board Review 2008: High-Yield MCQs (Set 2) - Figure 39

. Infection
. Lymphoma
. Paget's disease
. Massive bone infarct
. Old pelvic trauma

Correct Answer & Explanation

. Paget's disease

Explanation

The radiograph shows enlargement of the bone, coarse trabeculation, a blastic appearance, and thickening of the cortex, revealing the classic appearance of Paget's disease in the sclerotic phase, the most common presentation. While lymphoma may present as a blastic lesion, it will not have the same enlargement, coarse trabeculation of bone, and the significant sclerosis seen here. Menendez LR (ed): Orthopaedic Knowledge Update: Musculoskeletal Tumors. Rosemont, IL, American Academy of Orthopaedic Surgeons, 2002, pp 211-215.

Question 4457

Topic: 1. General Principles & Basic Science

A 12-year-old girl with juvenile rheumatoid arthritis (JRA) has had chronic pain and synovitis about the knee that is now well-controlled medically. Examination reveals 20 degrees of valgus at the knee. Knee range of motion shows 10 degrees to 90 degrees of flexion. Treatment should consist of

. arthroscopic synovectomy.
. open synovectomy.
. staple hemiepiphyseodesis.
. knee arthrodesis.
. varus osteotomy.

Correct Answer & Explanation

. staple hemiepiphyseodesis.

Explanation

Children with JRA frequently have valgus in association with hypervascularity because of chronic inflammation. This is normally caused by overgrowth of the medial femoral epiphysis. Staple hemiepiphyseodesis, if done early, can reverse the deformity. Osteotomy is usually unnecessary at this age, and there is a risk of stiffness of the knee following the procedure. Synovectomy may be helpful but will not prevent or correct a deformity.

Question 4458

Topic: Infection, Pharmacology & VTE
A 3-year-old child has refused to walk for the past 2 days. Examination in the emergency department reveals a temperature of 102.2°F (39°C) and limited range of motion of the left hip. An AP pelvic radiograph is normal. Laboratory studies show a WBC count of 9,000/mm³, an erythrocyte sedimentation rate (ESR) of 65 mm/h, and a C-reactive protein level of 10.5 mg/L (normal < 0.4). What is the next most appropriate step in management?
. Technetium Tc 99m bone scan
. Intravenous antibiotics
. Oral antibiotics
. CT of the hips
. Aspiration of the left hip

Correct Answer & Explanation

. Aspiration of the left hip

Explanation

Examination reveals an irritable hip, creating a differential diagnosis of transient synovitis versus pyogenic hip arthritis. Kocher and associates described four criteria to help predict the presence of infection: inability to bear weight, fever, ESR of more than 40 mm/h, and a peripheral WBC count of more than 12,000/mm³. This patient meets three of the four criteria, with a positive predictive value of 73% to 93% for joint infection. Therefore, aspiration of the hip is warranted, with a high likelihood that emergent hip arthrotomy will be indicated. Ideally, intravenous antibiotics should be administered after culture material has been obtained from needle aspiration of the hip. An urgent bone scan is better indicated as a screening test for sacroiliitis or diskitis. If the arthrocentesis proves negative, CT or MRI of the pelvis may be indicated to rule out a pelvic or psoas abscess.

Question 4459

Topic: Infection, Pharmacology & VTE

The parents of a previously healthy 3-year-old child report that she refused to walk on awakening. Examination later in the day reveals that the patient can walk but with a noticeable limp. She has a temperature of 99.5 degrees F (37.5 degrees C). Range of motion measurements are shown in Figure 50. An AP pelvis radiograph is normal. Laboratory studies show a WBC count of 9,000/mm3 and an erythrocyte sedimentation rate of 10 mm/h. Management should consist of

Pediatrics Board Review 2004: High-Yield MCQs (Set 4) - Figure 16

. observation.
. technetium Tc 99m bone scan.
. MRI of the pelvis.
. aspiration of the hip joint.
. IV antibiotics.

Correct Answer & Explanation

. observation.

Explanation

The patient has the typical history and presentation of transient synovitis of the hip, a condition that is more common in children age 2 to 5 years but which may affect children up to 12 years. The discomfort typically is noted on awakening, and the child will refuse to walk. Later in the day, the pain commonly improves and the child can walk but will have a limp. Mild to moderate restriction of hip abduction is the most sensitive range-of-motion restriction. The extent of the evaluation for transient synovitis depends on the intensity and duration of symptoms. Because she has been afebrile for the past 24 hours, observation is the management of choice. In the differential diagnosis of suspected transient synovitis, septic arthritis of the hip is the primary disorder to exclude. Osteomyelitis of the proximal femur also should be considered. In most patients, clinical examination will differentiate of these disorders to a reasonable certainty. Plain radiographs are normal in the early stage of an infectious process. Ultrasonography shows increased fluid in the hip joint in both transient synovitis and septic arthritis. MRI can differentiate the two conditions; however, this test would require general anesthesia and is not required in most patients in this age group. If a child with transient synovitis has a concurrent infectious process such as an upper respiratory tract infection or otitis media, the temperature will most likely be elevated. In this situation, a full evaluation for an infectious process and initiation of IV antibiotics should be considered. This would include radiographs, CBC count, erythrocyte sedimentation rate, blood cultures, aspiration of the hip joint, and IV antibiotics. Del Beccaro MA, Champoux AN, Bockers T, Mendelman PM: Septic arthritis versus transient synovitis of the hip: The value of screening laboratory tests. Annals Emerg Med 1992;21:1418-1422.

Question 4460

Topic: 1. General Principles & Basic Science

A 30-year-old patient has acetabular dysplasia and moderate secondary osteoarthrosis. Which of the following studies will best help predict the success of periacetabular osteotomy?

. High-resolution CT with coronal and sagittal reconstructions
. Glycosaminoglycan MRI
. Functional radiographic or fluoroscopic evaluation
. Gadolinium-contrast arthrography with MRI
. Routine AP and lateral radiographs

Correct Answer & Explanation

. Functional radiographic or fluoroscopic evaluation

Explanation

Improvement in the appearance of the hip joint on functional radiographic evaluation (abduction/adduction views) has been shown to be predictive of outcome following joint preserving surgery. CT and MRI findings have not been shown to be predictive of outcome.

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