Menu

3. Adult Reconstruction (Hip & Knee) MCQs

Practice Set 113 of 326

This practice set contains high-yield board review questions covering key concepts in 3. Adult Reconstruction (Hip & Knee). Each clinical scenario is designed to test your diagnostic and management skills relevant to this subspecialty.

Question 2241

Topic: 3. Adult Reconstruction (Hip & Knee)

Figure 49 shows a histologic section of the lung in a patient who died during total hip arthroplasty. What unexpected finding is seen in the pulmonary capillaries?

Hip & Knee Reconstruction Board Review 2007: High-Yield MCQs (Set 4) - Figure 6

. Pulmonary embolism
. Methylmethacrylate cement
. Hemorrhagic infarct
. Granuloma formation
. Amyloid

Correct Answer & Explanation

. Methylmethacrylate cement

Explanation

Sudden death during total hip arthroplasty has been reported. In a report from the Mayo Clinic, intraoperative death occurred during cemented total hip arthroplasty in 23 patients. Fat and marrow embolization during preparation of the femur or cementing of the femoral component was believed to be responsible for the cardiopulmonary collapse that occurred during arthroplasty. Although fat and marrow emboli were found in the pulmonary capillaries of most of the patients on autopsy, this histologic section shows two particles of cement in the pulmonary capillaries. Parvizi J, Holiday AD, Ereth MH, et al: The Frank Stinchfield Award. Sudden death during primary hip arthroplasty. Clin Orthop 1999;369:39-48.

Question 2242

Topic: 3. Adult Reconstruction (Hip & Knee)

A 50-year-old man with metastatic renal cell carcinoma has right hip pain. A radiograph and CT scan are shown in Figures 48a and 48b. The first step in management should consist of

. administration of intravenous bisphosphonates.
. cemented right total hip arthroplasty with acetabular reconstruction.
. external beam radiation.
. embolization of the lesion.
. percutaneous cementoplasty.

Correct Answer & Explanation

. embolization of the lesion.

Explanation

These lesions are extremely vascular and can cause uncontrolled intraoperative bleeding; therefore embolization is the appropriate first treatment. Because the radiograph and CT scan show a lytic lesion in the supra-acetabular region that affects the weight-bearing dome and medial wall, the next step in treatment would most likely be a total hip arthroplasty and acetabular reconstruction. Treatment with bisphosphonates and radiation therapy will not prevent an acetabular fracture. Cementoplasty is an emerging technique in which cement is injected percutaneously into a lesion, but no long-term results have been reported. Radiofrequency ablation of bone metastases is also an emerging technique that provides palliative pain control. Layalle I, Flandroy P, Trotteur G, Dondelinger RF: Arterial embolization of bone metastases: Is it worthwhile? J Belge Radiol 1998;81:223-225.

Question 2243

Topic: 3. Adult Reconstruction (Hip & Knee)

Figures 2a and 2b show the radiographs of a 72-year-old man with aseptic loosening of the tibial component of his total knee arthroplasty. Optimal management should include

. tibial revision only, without stems or augmentations.
. tibial revision only, with stems and augmentations.
. revision of the tibial and femoral components, without stems or augmentations.
. revision of the tibial and femoral components, with stems and augmentations.
. primary arthrodesis.

Correct Answer & Explanation

. revision of the tibial and femoral components, with stems and augmentations.

Explanation

The radiographs show massive subsidence of the lateral side of the tibia with severe tibial bone loss and a fractured proximal fibula. Reconstruction should consist of a large metal or bony lateral tibial augmentation, and a stem long enough to bypass the defect is required. The femoral and tibial components are articulating without any remaining polyethylene medially; therefore, the femoral component is damaged and needs revision. The insertions of the lateral ligaments are absent, thereby rendering the lateral side of the knee predictably unstable. Also, the large valgus deformity compromises the medial collateral ligament. The posterior cruciate ligament is also likely to be deficient with this much tibial bone destruction. The patient requires a posterior stabilized femoral component at the minimum, and possibly a constrained femoral component. Retention of the femoral component, even though it may be well-fixed, jeopardizes the outcome. Lotke PA, Garino JP: Revision Total Knee Arthroplasty. New York, NY, Lippincott-Raven, 1999, pp 137-250. Insall JN, Windsor RE, Scott WN, et al: (eds): Surgery of the Knee, ed 2. New York, NY, Churchill Livingstone, 1993, pp 935-957.

Question 2244

Topic: 3. Adult Reconstruction (Hip & Knee)

What is the average linear wear rate of a conventional, noncross-linked ultra-high molecular weight polyethylene liner used in total hip arthroplasty?

. 0.01 to 0.05 mm/yr
. 0.1 to 0.2 mm/yr
. 0.5 to 1 mm/yr
. 1 to 2 mm/yr
. Greater than 2 mm/yr

Correct Answer & Explanation

. 0.1 to 0.2 mm/yr

Explanation

Several studies have shown that ultra-high molecular weight polyethylene liners used in total hip arthroplasties wear at a rate of 0.1 to 0.2 mm/yr. The orthopaedic surgeon performing total hip arthroplasties should be aware of the average wear rate so that potential problems can be identified when following patients postoperatively. Callaghan JJ, Albright JC, Goetz DD, Olejniczak JP, Johnston RC: Charnley total hip arthroplasty with cement: Minimum twenty-five year follow-up. J Bone Joint Surg Am 2000;82:487-497.

Question 2245

Topic: Total Knee Arthroplasty (TKA)

During total knee arthroplasty, what component position aids in proper tracking and stability of the patellar component?

. Femoral component in external rotation
. Tibial component in internal rotation
. Medialization of the tibial tray
. Lateralization of the patellar component
. Medialization of the femoral component

Correct Answer & Explanation

. Tibial component in internal rotation

Explanation

The femoral component should be implanted with enough external rotation to facilitate patellar tracking. Proper tracking requires a normal Q angle and is affected by axial and rotational alignment of the femur and tibia. An excessive Q angle can result from internal rotation of either component, medialization of the tibial tray, or lateralization of the patellar component. Beaty JH (ed): Orthopaedic Knowledge Update 6. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1999, pp 559-582.

Question 2246

Topic: 3. Adult Reconstruction (Hip & Knee)

Figures 10a through 10c show the radiographs of an 85-year-old man who underwent a revision total knee arthroplasty for loosening of the tibial component 6 months ago. He now reports a mildly uncomfortable mass on the anterior part of the knee joint. Examination reveals 95 degrees of motion and good quadriceps strength, and he can ambulate with minimal pain with a walker. History reveals chronic lymphocytic leukemia for which he is taking antineoplastic medication. Culture of the mass aspirate grew Candida albicans on two separate occasions. The patient and the family strongly prefer nonsurgical management. If long-term suppression is chosen as treatment, what advice should be given to the patient and family?

. There is a less than a 50% chance of long-term success.
. There will be no significant increase in pain or swelling.
. Close clinical and laboratory follow-up is not necessary.
. Weight bearing and ambulation should be curtailed.
. Weight bearing and ambulation are allowed but only with bracing.

Correct Answer & Explanation

. There is a less than a 50% chance of long-term success.

Explanation

In patients with infected implants, treatment usually involves debridement and exchange of the infected components. In rare cases, when there is severe comorbidity and immune system compromise, as there is with this patient, a form of chronic suppression is indicated. This patient's function is quite satisfactory and, even though there is only a 21% to 38% chance of success (Hirawaka as quoted by Mulvey and Thornhill), an attempt at suppression therapy is indicated. The patient must be followed closely to monitor the potential complications of long-term antifungal therapy and to monitor the integrity of the joint, looking for bone or soft-tissue destruction. Because the patient has satisfactory motion and quadriceps strength, no bracing or other assistive device (except for the walker he is now using) is indicated.

Question 2247

Topic: 3. Adult Reconstruction (Hip & Knee)

A 37-year-old man who works in a factory has isolated, lateral unicompartmental pain about his knee with activities. Nonsurgical management has failed to provide relief. The radiograph shown in Figure 45 reveals a tibiofemoral angle of approximately 15 degrees which is clinically correctable to neutral. What is the best surgical option in this patient?

Hip & Knee Reconstruction Board Review 2007: High-Yield MCQs (Set 4) - Figure 1

. Unicompartmental arthroplasty
. Total knee arthroplasty
. Lateral closing wedge proximal tibial osteotomy
. Medial opening wedge proximal tibial osteotomy
. Medial closing wedge supracondylar femoral osteotomy

Correct Answer & Explanation

. Medial closing wedge supracondylar femoral osteotomy

Explanation

Patients with a valgus alignment about the knee can have lateral compartment arthritis. Similar to a high tibial osteotomy, a supracondylar femoral osteotomy is indicated in younger patients who have a more active lifestyle and isolated unicompartmental disease. In this young patient who works in a factory and has a valgus knee, a medial closing wedge supracondylar femoral osteotomy is the treatment of choice. The role of arthroplasty is limited in younger patients. Mathews J, Cobb AG, Richardson S, et al: Distal femoral osteotomy for lateral compartment osteoarthritis of the knee. Orthopedics 1998;21:437-440.

Question 2248

Topic: 3. Adult Reconstruction (Hip & Knee)

Figures 23a and 23b show the AP and lateral radiographs of a 67-year-old woman who has severe left knee pain when ambulating. History reveals that she underwent primary total knee arthroplasty 7 years ago. The patient reports increasing deformity over the past several years and uses a knee brace and a cane. Examination reveals that she walks with a varus thrust and has an uncorrectable varus deformity with valgus force. What is the primary reason for implant failure?

. Osteolysis
. Polyethylene wear
. Tibial component fixation failure
. Modular tibial component failure
. Posterior cruciate ligament retention

Correct Answer & Explanation

. Tibial component fixation failure

Explanation

Both cemented and cementless total knee arthroplasties depend on adequate fixation of the tibial component to promote long-term survivorship. An effective stem and adequate peripheral fixation of the tibial component to the cancellous-cortical portion of the proximal tibia are necessary for cementless fixation. Peripheral screws and pegs can serve as adjunctive fixation to decrease micromotion and shear forces and allow bone ingrowth to occur. Careful preparation of the proximal tibial surface can minimize fixation failure. Cemented fixation of the tibial stem should be performed in addition to the plateau. Osteolysis, polyethylene wear, and failure at the insert/tray locking mechanism have not occurred. Posterior cruciate ligament retention has not caused the tibial component fixation failure.

Question 2249

Topic: 3. Adult Reconstruction (Hip & Knee)

A 77-year-old woman who underwent total knee arthroplasty 16 years ago now reports pain, swelling, and notable crepitation with range of motion. AP, lateral, and Merchant radiographs are shown in Figures 54a through 54c. What is the most likely diagnosis?

. Failure of patellar polyethylene
. Loosening of the femoral component
. Loosening of the tibial component
. Loosening of the patellar component
. Wear-induced osteolysis

Correct Answer & Explanation

. Failure of patellar polyethylene

Explanation

The Merchant radiograph shows a lateral patellar shift with total polyethylene failure, resulting in a metal-on-metal bearing. This problem is associated with metal-backed patellar components. Component fixation appears solid, and no osteolysis is evident. Poss R (ed): Orthopaedic Knowledge Update 3. Park Ridge, IL, American Academy of Orthopaedic Surgeons, 1990, pp 590-593. Leopold SS, Berger RA, Patterson L, et al: Serum titanium level for diagnosis of a failed metal-backed patellar component. J Arthroplasty 2000;15:938-943.

Question 2250

Topic: 3. Adult Reconstruction (Hip & Knee)

Figure 1 shows the radiograph of an 18-year-old patient who has severe knee pain. Treatment consisting of osteotomy should be perfomed

Hip 2004 Practice Questions: Set 1 (Solved) - Figure 2

. above the tibial tubercle.
. at or just below the tibial tubercle.
. in the tibial diaphysis.
. on both the femur and tibia.
. on the femur alone.

Correct Answer & Explanation

. at or just below the tibial tubercle.

Explanation

Very large corrections of tibial deformity can be achieved at or just below the tibial tubercle. This level of osteotomy maintains the relationship between the tubercle and the rest of the joint, does not alter patellofemoral mechanics, and avoids complicating possible future conversion to total knee arthroplasty. High tibial osteotomy is contraindicated for large corrections because of excessive elevation of the tibial tubercle and overhang of the lateral plateau. Correction in the tibial diaphysis creates a zig zag pattern in the tibia by correcting below the deformity and risks nonunion in cortical bone. There is no evidence that the femur is deformed; therefore, femoral osteotomy is not indicated.

Question 2251

Topic: 3. Adult Reconstruction (Hip & Knee)

A 68-year-old woman underwent a successful total right hip arthroplasty with a metal-on-metal articulation and cementless porous-coated components. Three months later, she underwent identical surgery on the left hip. Three months after surgery on the left hip, she reports groin pain on ambulation. Examination reveals significant groin discomfort with passive hip motion, particularly at the extremes of motion. Radiographs are shown in Figures 21a and 21b. Laboratory studies show an erythrocyte sedimentation rate of 35 mm/h and a C-reactive protein of 0.9. Aspiration yields scant growth of Staphylococcus epidermidis in the broth only, with no evidence of loosening on arthrography. A second aspiration yields scant growth of Staphylococcus epidermidis in the broth only. What is the most likely cause of the patient's pain?

. Allergic metal synovitis
. Aseptic loosening of the acetabular component
. Septic loosening of the acetabulum
. Deconditioning following hip arthroplasty
. Iliopsoas tendinitis

Correct Answer & Explanation

. Septic loosening of the acetabulum

Explanation

The difference in the clinical results combined with the laboratory findings points to infection. While there is a significant risk of false-positive findings with aspiration, the fact that two successive aspirations grew the same organism strongly suggests infection. The radiograph shows that there is more radiolucency around the left acetabular component than the right component. White RE: Evaluation of the painful total hip arthroplasty, in Callaghan JJ, Rosenberg AG, Rubash HE (eds): The Adult Hip. Philadelphia, PA, Lippincott-Raven, 1998, vol 2, pp 1377-1385.

Question 2252

Topic: 3. Adult Reconstruction (Hip & Knee)

A 75-year-old patient returns for follow-up after undergoing bilateral total hip arthroplasty (THA). The right hip is a hybrid THA performed 12 years ago, whereas the left hip is a cementless THA performed 10 years ago. Both acetabular components are the same type, same size, and from the same manufacturer. Both femoral heads are 28-mm cobalt-chromium components. What is the most likely explanation for the advanced polyethylene wear in one hip?

. Presence of a third-party abrasive particle
. Disproportionate use of the limbs by the patient
. Defective femoral head
. Method of fixation of the femoral component
. Method of sterilization and shelf life of the polyethylene

Correct Answer & Explanation

. Method of sterilization and shelf life of the polyethylene

Explanation

Over the past three decades, gamma irradiation and air has been the most common method of sterilizing polyethylene used in total joint arthroplasty. This method of sterilization results in breakage of the chemical bonds within the polymer. While this promotes cross-linking, it also leaves the polyethylene vulnerable to oxidation, especially if packaged in an air environment. Oxidation has been shown to decrease polyethylene's molecular weight, ultimate tensile strength, elongation, and toughness which results in a stiffer, more brittle material that is less resistant to wear. Severity of oxidation and a decrease in mechanical properties have been shown to be related to the length of time that the component is exposed to air (the shelf life). Currier and associates studied the clinical performance of gamma irradiated in air polyethylene components that had been shelf aged. They demonstrated that for the first 5 years of shelf life, polyethylene oxidized rather slowly. However, polyethylene components with a shelf life of more than 5 years would be expected to have minimal mechanical toughness and would likely fail rapidly if implanted. Bohl and associates evaluated 135 patients who had undergone total knee arthroplasty. Survivorship at 5 years was 100% for components with a shelf life of less than 4 years, 89% for components with a shelf life of 4 to 8 years, and 79% for components with a shelf life of more than 8 years. Sychterz and associates reported no correlation between shelf life and true wear rates for components with a shelf life of less than 3 years. In summary, both in vivo and in vitro data suggest that shelf life in excess of 3 to 5 years has a direct effect on wear of polyethylene. Currier BH, Currier JH, Collier JP, et al: Shelf life and in vivo duration: Impacts on performance of tibial bearings. Clin Orthop 1997;342:111-122. Bohl JR, Bohl WR, Postak PD, et al: The Coventry Award: The effects of shelf life on clinical outcome for gamma sterilized polyethylene tibial components. Clin Orthop 1999;367:28-38.

Question 2253

Topic: 3. Adult Reconstruction (Hip & Knee)

Familial (Leiden) thrombophilia is of importance in joint arthroplasty because of an abnormality in the clotting cascade. Which of the following statements best describes the condition?

. It is a disease caused by an abnormality of platelets that leads to increased blood clotting.
. It is a disease caused by an abnormality of vascular endothelium that leads to increased blood clotting.
. It is a disease caused by an abnormality of hepatic metabolism that leads to decreased production of factor V and decreased blood clotting.
. It is a disease caused by an abnormality of factor V that leads to decreased inactivation of factor Va by activated protein C (aPC) and increased blood clotting.
. It is a familial, genetic disease that requires placement of a Greenfield filter in all individuals who have the abnormality, prior to surgery.

Correct Answer & Explanation

. It is a disease caused by an abnormality of factor V that leads to decreased inactivation of factor Va by activated protein C (aPC) and increased blood clotting.

Explanation

Factor V Leiden is a disease caused by an abnormality of factor V in which a single amino acid substitution of glutamine for arginine in the protein C cleavage region leads to decreased inactivation of factor V and thus a greater tendency to form clots. More than half of all individuals with Factor V Leiden will develop deep venous thrombosis in the presence of a single additional risk factor such as long bone fracture or total joint arthroplasty.

Question 2254

Topic: 3. Adult Reconstruction (Hip & Knee)

A 26-year-old man has had a 2-year history of pain and stiffness after sustaining a comminuted olecranon fracture. Treatment at the time of injury consisted of open reduction and internal fixation with tension band wiring. Examination reveals motion of 45 degrees to 110 degrees and pain throughout the arc of motion. Resisted flexion and extension are painful. Forearm rotation is normal. Radiographs are shown in Figure 51. Treatment should consist of

Shoulder Board Review 2002: High-Yield MCQs (Set 4) - Figure 17

. excision of heterotopic bone.
. hardware removal and elbow joint release with splinting.
. semiconstrained total elbow arthroplasty.
. distraction arthroplasty.
. synovectomy and radial head excision.

Correct Answer & Explanation

. hardware removal and elbow joint release with splinting.

Explanation

The patient has posttraumatic arthritis of the elbow; therefore, the treatment of choice is hardware removal and soft-tissue releases with splinting to avoid recurrence of contractures. The combination of pain and stiffness in an elbow that has sustained significant joint surface damage renders it unresponsive to simple soft-tissue releases and heterotopic bone excision. Joint distraction and interposition arthroplasty offer the possibility of maintaining motion and relieving pain as a later salvage procedure. Joint replacement should not be performed in young, active, strong individuals because the prosthesis will fail quickly and complications will develop. Synovectomy and radial head excision are not indicated. Morrey BF: Distraction arthroplasty: Clinical applications. Clin Orthop 1993;293:46-54.

Question 2255

Topic: 3. Adult Reconstruction (Hip & Knee)

Fully dense alumina and zirconia materials have been used as bearing materials in hip arthroplasty to provide greater wear resistance than polished metallic surfaces. Although both have shown reduced wear clinically, what concerns continue to exist about the use of zirconia?

. Less tough than alumina, increasing the chance of brittle failure
. May undergo a phase change that markedly reduces wear resistance
. Not as biocompatible as other bearing materials
. Susceptible to crevice corrosion
. Susceptible to fatigue fracture

Correct Answer & Explanation

. May undergo a phase change that markedly reduces wear resistance

Explanation

Zirconia as a bearing surface is "metastable," meaning that, in the microstructure of the material the zirconia molecules are ordered in a tetragonal fashion, but they can easily transform to a monoclinic microstructure that is less wear resistant. Transformation can occur with input of enough energy (eg, thermal energy imparted by steam sterilization or mechanical energy at the bearing surface). Zirconia was introduced as an alternative to alumina because it has a higher toughness, making it less susceptible to gross fracture (ceramics do not undergo fatigue fracture, but rather fail from a process of slow crack growth). Zirconia is highly biocompatible (as are many ceramics) and is essentially immune to corrosive processes that can plague metallic alloys such as stainless steel. Clarke IC, Manaka M, Green DD, et al: Current status of zirconia used in total hip implants. J Bone Joint Surg Am 2003;85:73-84. Haraguchi K, Sugano N, Nishii T, et al: Phase transformation of a zirconia ceramic head after total hip arthroplasty. J Bone Joint Surg Br 2001;83:996-1000.

Question 2256

Topic: 3. Adult Reconstruction (Hip & Knee)

Figures 35a and 35b show the radiographs of a patient who underwent debridement of a chronically infected, fully constrained knee prosthesis and now reports pain and instability despite bracing. History reveals that the patient has had no drainage since undergoing the last debridement 6 months ago. A C-reactive protein level and aspiration are negative for infection. Treatment should now consist of

. knee arthrodesis.
. insertion of a semiconstrained prosthesis.
. insertion of an antibiotic-impregnated polymethylmethacrylate (PMMA) spacer.
. reconstruction of the extensor mechanism.
. amputation.

Correct Answer & Explanation

. knee arthrodesis.

Explanation

The radiographs show a significant loss of the proximal anterior tibial cortex, consistent with an extensively damaged or deficient extensor mechanism. Such a deficit precludes insertion of another knee arthroplasty. Arthrodesis is the treatment of choice for this patient and is indicated for loss of the extensor mechanism and knee instability. A recent report on arthrodesis following removal of an infected prosthesis showed a union rate of 91% using a short intramedullary nail. Insertion of an antibiotic-impregnated PMMA spacer is not indicated because the rationale for using a spacer is to maintain a space for reinsertion of another prosthesis. Reconstruction of the extensor mechanism would not address the loss of the joint. Amputation is the final treatment option if the arthrodesis fails. Rand JA: Alternatives to reimplantation for salvage of the total knee arthroplasty complicated by infection. J Bone Joint Surg Am 1993;75:282-289. Lai KA, Shen WJ, Yang CY: Arthrodesis with a short Huckstep nail as a salvage procedure for failed total knee arthroplasty. J Bone Joint Surg Am 1998;80:380-388.

Question 2257

Topic: 3. Adult Reconstruction (Hip & Knee)

During primary total knee arthroplasty with trial implants in place, the surgeon notes technically satisfactory patellar resurfacing and restoration of a physiologic mechanical axis but excessively lateral patellar tracking. Treatment should now include

. a lateral retinacular release.
. a tubercle transfer to reduce the Q angle.
. a repeat of the tibial and femoral cuts to introduce 5 degrees of varus.
. release of the popliteus.
. medial vastus advancement.

Correct Answer & Explanation

. a lateral retinacular release.

Explanation

The most common causes of patellar instability after total knee arthroplasty are valgus malalignment, internal rotation of the femoral or tibial component, medialization of the femoral component, errors in patellar preparation and resurfacing, and failure to perform a lateral release. These factors should be addressed before considering capsular closure. Distal extensor mechanism realignment should be avoided because of the complication rate. The proximal extensor mechanism would not adequately compensate for implant malrotation. Barnes CL, Scott RD: Patellofemoral complications of total knee replacement, in Heckman JD (ed): Instructional Course Lectures 42. Rosemont, IL, American Academy of Orthopaedic Surgeons, 1993, pp 309-314.

Question 2258

Topic: 3. Adult Reconstruction (Hip & Knee)

A 65-year-old man has a painful and often audible crepitus after undergoing a total knee arthroplasty 8 months ago. His symptoms are reproduced with active extension of about 30 degrees. Examination reveals no effusion or localized tenderness, a stable knee, and a range of motion of 5 degrees to 120 degrees. Radiographs are shown in Figures 37a and 37b. Management should consist of

. revision of all components to ensure patellar tracking.
. athroscopic debridement.
. arthrotomy and keloid excision.
. intra-articular corticosteroid injections.
. patellar component revision.

Correct Answer & Explanation

. athroscopic debridement.

Explanation

This is a typical presentation of the patellar clunk syndrome. The syndrome usually follows implantation of a posterior stabilized prosthesis. It is thought to be the result of femoral component design and altered extensor mechanics. The condition usually resolves with arthroscopic debridement of the suprapatellar fibrous nodule. Arthrotomy or revision is seldom warranted. Beight JL, Yao B, Hozack WJ, Hearn SL, Booth RE Jr: The patellar "clunk" syndrome after posterior stabilized total knee arthroplasty. Clin Orthop 1994;299:139-142.

Question 2259

Topic: 3. Adult Reconstruction (Hip & Knee)

A 51-year-old male truck driver has had progressive left hip pain for more than 2 years, and he reports that the pain has become severe in the past 9 months. He is now unable to work because of the pain. Examination reveals that range of motion of the hip is limited to 95 degrees of flexion, 0 degrees of internal rotation, and 20 degrees of external rotation. The plain radiograph, MRI scan, and intraoperative gross photographs are shown in Figures 9a through 9d. Management should consist of

. synovectomy.
. local excision with arthroplasty.
. radiation synovectomy.
. radiation therapy.
. radical resection.

Correct Answer & Explanation

. synovectomy.

Explanation

The diagnosis is synovial chondromatosis. While the plain radiograph fails to show any calcifications, the MRI scan shows an intra-articular mass that involves the capsule. Grossly multiple granular cartilage nodules are seen. Management should consist of removing all loose bodies along with the synovial membrane.

Question 2260

Topic: 3. Adult Reconstruction (Hip & Knee)

Treatment of a cruciate-retaining total knee that is unstable in flexion is best accomplished by

Hip Board Review 2001: High-Yield MCQs (Set 2) - Figure 15

. revising the implant to a posterior stabilized device.
. revising the implant with a thinner polyethylene insert.
. revising the implant with a larger femoral component.
. limiting flexion to only 90 degrees.
. using quadriceps conditioning exercises and a derotation brace.

Correct Answer & Explanation

. revising the implant to a posterior stabilized device.

Explanation

Pagnano and associates revised 25 painful primary posterior cruciate-retaining total knee arthroplasties for flexion instability. The patients shared typical clinical presentations that included a sense of instability without frank giving way, recurrent knee joint effusion, soft-tissue tenderness involving the pes anserine tendons and the retinacular tissue, posterior instability of 2+ or 3+ with a posterior drawer or a posterior sag sign at 90 degrees of flexion, and above-average motion of the total knee arthroplasty. Twenty-two of the knee replacements were revised to posterior stabilized implants, and three underwent tibial polyethylene liner exchange only. Nineteen of the 22 knee replacements revised to a posterior stabilized implant showed marked improvement after the revision surgery. Only one of the three knee replacements that underwent tibial polyethylene exchange was improved. Flexion instability can be a cause of persistent pain and functional impairment after posterior cruciate-retaining total knee arthroplasty. Revision surgery that focuses on balancing the flexion and extension spaces, in conjunction with a posterior stabilized knee implant, seems to be a reliable treatment for symptomatic flexion instability after posterior cruciate-retaining total knee arthroplasty.

Test Yourself

Switch to an interactive, timed exam simulation to truly master this topic.

On this Page