3. Adult Reconstruction (Hip & Knee) MCQs

The AP radiograph demonstrates extensive periacetabular osteolysis. The central hole eliminator has dissociated from the shell and migrated into a lytic defect in the ischium. In a retrieval study, most periacetabular osteolytic lesions had a clear communication pathway with the joint space. Lesions with communication to the joint via several pathways or through a central dome hole (as in this patient) were larger and more likely to be associated with cortical erosion. Although periprosthetic tumors have been described, they are rare and particle-induced inflammation around a prosthesis does not seem to increase the risk for carcinogenesis. Visuri T, Pulkkinen P, Paavolainen P: Malignant tumors at the site of total hip prosthesis: Analytic review of 46 cases. J Arthroplasty 2006;21:311-323. Bezwada HP, Shah AR, Zambito K, et al: Distal femoral allograft reconstruction for massive osteolytic bone loss in revision total knee arthroplasty. J Arthroplasty 2006;21:242-248.

The patient has osteonecrosis of the lateral femoral condyle with collapse of the articular surface. Because there is already collapse of the articular surface, a total knee arthroplasty is the treatment of choice. The results of total knee arthroplasty in these patients are usually excellent. However, knee replacement is only a resurfacing procedure, and some patients with global osteonecrosis of the distal femur may have residual pain after knee replacement. High tibial osteotomy may be indicated in younger patients who have a varus deformity and localized osteonecrosis. Arthroscopic surgery would provide minimal relief for this patient because there is already collapse of the articular surface. A hinged knee brace will not adequately unload the joint. An osteochondral allograft should be considered only for younger patients with localized osteonecrosis. Bergman NR, Rand JA: Total knee arthroplasty in osteonecrosis. Clin Orthop 1991;273:77-82.

Revision of a failed patellar component can be difficult because of bone loss and damage to the extensor mechanism. Several authors have advised against reinsertion of a patellar component if the residual patellar thickness is 10 mm or less. Leaving an unresurfaced bony remnant in place at the time of revision or reimplantation surgery has been shown to be a reasonable option; however, the results are of a lower quality when compared with revision surgery where the patellar component can be retained or revised. The other treatment options have not been shown to be effective approaches to this problem. Rand JA: The patellofemoral joint in total knee arthroplasty. J Bone Joint Surg Am 1994;76:612-620. Pagnano MW, Scuderi GR, Insall JN: Patellar component resection in revision and reimplantation total knee arthroplasty. Clin Orthop 1998;356:134-138.

Stiffness following primary total knee arthroplasty remains a vexing problem. Treatment options have included extensive physical therapy, dynamic splinting, manipulation under anesthesia, arthroscopic arthrolysis, open arthrolysis with polyethylene exchange, and ultimately revision arthroplasty. Results are not as gratifying as would be expected. Babis and associates performed an open arthrolysis and polyethylene exchange on seven patients who were followed for a mean of 4.2 months. The results were poor. The mean improvement in arc of motion was only 20 degrees. Nicholls and Dorr treated 13 patients for stiffness. Only 40% of those patients obtained good to excellent results. Four patients (30%) required manipulation because of recurrent stiffness postoperatively. They noted they could not predictably improve the arc of motion with a revision operation. Haidukewych and associates reported on 15 patients who underwent revision of well-fixed components after total knee arthroplasty for stiffness. Of the 15 patients, 10 (66%) were satisfied with the outcome revision. Interestingly, they noted that in patients for whom the total arc of motion did not improve but who regained near full extension, there was a greater amount of satisfaction with the procedure than for those who did not regain full extension. Babis GC, Trousdale RT, Pagnano MW, et al: Poor outcomes of isolated tibial insert exchange and arthrolysis for the management of stiffness following total knee arthroplasty. J Bone Joint Surg Am 2001;83:1534-1536. Nicholls DW, Dorr LD: Revision surgery for stiff total knee arthroplasty. J Arthroplasty 1990;5:S73-S77.

In a patient with bilateral hip dysplasia, there are significant technical challenges that need to be addressed to ensure a successful total hip arthroplasty. Restoring the center of the hip may cause significant lengthening and require femoral shortening. Lengthening of greater than 4 cm can lead to sciatic nerve palsy that will present clinically as a foot drop. A high hip center can be used when there is inadequate bone stock in the acetabulum to achieve adequate host bone coverage. A modular femoral implant may be used for a dysplastic hip with significant rotational deformity. Although an anterolateral approach to the hip may decrease the incidence of sciatic nerve palsy during the exposure, it will not be helpful when there is more than 4 cm of limb lengthening. Schmalzried TP, Amstutz HC, Dorey FJ: Nerve palsy associated with total hip replacement: Risk factors and prognosis. J Bone Joint Surg Am 1991;73:1074-1080. Papagelopoulos PJ, Trousdale RT, Lewallen DG: Total hip arthroplasty with femoral osteotomy for proximal femoral deformity. Clin Orthop 1996;332:151-162.

The patient has symptomatic postoperative heterotopic ossification after total hip arthroplasty. Postoperative prophylactic treatments include nonsteroidal anti-inflammatory drugs (usually indomethacin) or low-dose irradiation. The heterotopic ossification shown here is quite mature; therefore, nonsurgical management will not be successful. Surgical excision of grade III or IV heterotopic ossification should be followed with postoperative irradiation to minimize the chances of recurrence. Ayers DC, Evarts CM, Parkinson JR: The prevention of heterotopic ossification in high-risk patients by low-dose radiation therapy after total hip arthroplasty. J Bone Joint Surg Am 1986;68:1423-1430.

One of the most common complications of hemiarthroplasty is acetabular cartilage degeneration, resulting in increasing pain. Conversion total hip arthroplasty generally is successful with placement of an acetabular cup. Additionally, many patients with osteonecrosis already have degenerative changes of the acetabular cartilage even though radiographic findings may appear normal. Steinberg ME, Corces A, Fallon M: Acetabular involvement in osteonecrosis of the femoral head. J Bone Joint Surg Am 1999;81:60-65.

In the active, physiologically young, older patient with a displaced femoral neck fracture, Total Hip Arthroplasty (THA) provides better functional outcomes and lower rates of reoperation compared to hemiarthroplasty. Reoperations following hemiarthroplasty are often due to acetabular wear, groin pain, or loosening. However, THA is associated with a higher risk of dislocation, longer operative times, and greater blood loss. Mortality rates at 1 year are generally comparable between the two procedures in properly selected patients.

A retained bullet within a synovial joint (such as the hip or knee) is an absolute indication for surgical retrieval. Intra-articular bullets are bathed in synovial fluid, which dissolves the lead, increasing the risk of systemic lead toxicity (plumbism) and severe mechanical third-body wear to the articular cartilage. Observation or antibiotics alone are inappropriate. Chelation is not indicated unless systemic toxicity is confirmed and the source cannot be removed.

The patient has a neglected PIP joint fracture-dislocation with comminution involving more than 40% of the volar articular surface of the middle phalanx. Volar plate arthroplasty has been advocated for the treatment of acute unstable and chronic dorsal fracture-dislocations. The volar plate is incised laterally and released from the collateral ligaments. The volar fragments of the middle phalanx are removed and a trough is created for advancement of the volar plate, which is secured with sutures secured on the dorsum of the middle phalanx beneath the extensor mechanism. Dionysian E, Eaton RG: The long-term outcome of volar plate arthroplasty of the proximal interphalangeal joint. J Hand Surg Am 2000;25:429-437. Eaton RG, Malerich MM: Volar plate arthroplasty of the proximal interphalangeal joint: A review of ten years' experience. J Hand Surg Am 1980;5:260-268.

In healthy, active, community-ambulating elderly patients with displaced femoral neck fractures, total hip arthroplasty (THA) yields superior functional outcomes (e.g., higher Harris Hip Scores) and significantly lower reoperation rates compared to hemiarthroplasty, despite a slightly higher risk of early dislocation. Internal fixation for displaced fractures in this age group has an unacceptably high rate of failure and reoperation.

Femoral neck fractures in young adults are high-energy injuries considered orthopedic emergencies. Urgent open reduction and internal fixation (typically within 24 hours) is recommended to decompress the intracapsular hematoma and minimize the high risks of avascular necrosis and nonunion.

Femoral neck fractures in young adults are considered relative orthopedic emergencies. Urgent anatomic reduction and stable internal fixation (typically within 24 hours) is critical to preserve the native hip and reduce the incidence of AVN.

Neuropathic (Charcot) arthropathy with loss of protective sensation is an absolute contraindication to total ankle arthroplasty due to unacceptably high rates of failure, bone loss, and component subsidence.

Hawkins Type III fractures involve dislocation of both the subtalar and tibiotalar joints, disrupting all three major blood supplies to the talar body. This results in a high risk of avascular necrosis, approximately 75-90%.

Posterior sternoclavicular dislocations can compress critical mediastinal structures, causing dysphagia, dyspnea, or vascular compromise. A CT scan with contrast is mandatory to assess displacement and identify threatened mediastinal anatomy prior to any reduction attempt.

A coronal shear fracture involving the capitellum and the trochlea is a Dubberley Type 3. Due to the extensive medial involvement, a universal posterior approach, often combined with an olecranon osteotomy, is required for adequate visualization and fixation.

The primary blood supply to the scaphoid arises from the dorsal carpal branch of the radial artery, which enters the dorsal ridge at the distal pole. Blood then flows in a retrograde fashion to supply the proximal pole, predisposing it to avascular necrosis.

UHMWPE particles in the submicron range, specifically 0.1 to 1.0 micrometers, are most easily phagocytosed by macrophages. This phagocytosis triggers the release of pro-inflammatory cytokines like TNF-alpha and IL-1, leading to severe osteolysis.

Ceramics like alumina have extreme hardness and are highly scratch-resistant compared to metal alloys, resulting in exceptional wear characteristics and low friction. However, they are highly brittle and possess low fracture toughness, increasing the risk of catastrophic shattering.