3. Adult Reconstruction (Hip & Knee) MCQs

A 70-year-old female complains of knee instability 2 years after a primary total knee arthroplasty. On examination, the knee is well-balanced and stable in full extension, but demonstrates gross anterior-posterior and varus-valgus laxity at 90 degrees of flexion. Which of the following technical errors is the most likely cause of this finding?

Polyethylene wear debris in total hip arthroplasty (THA) is the primary initiator of macrophage-mediated osteolysis. Which specific mode of wear is the most common generator of these osteolytic submicron polyethylene particles?

A 65-year-old man undergoes primary total hip arthroplasty using a ceramic-on-ceramic bearing. At 2-year follow-up, he reports an audible squeaking sound from the hip during ambulation. What is the most significant biomechanical risk factor for this phenomenon?

During a total knee arthroplasty, the surgeon notes that the knee is perfectly balanced in extension but is significantly tight in flexion. Which of the following surgical steps is most appropriate to specifically address this mismatch?

In a Kaplan-Meier survivorship analysis of a new total hip arthroplasty implant, a patient dies from an unrelated myocardial infarction 5 years post-operatively with an intact, well-functioning implant. How is this patient's data handled in the analysis?

In ceramic-on-ceramic total hip arthroplasty, modern implants often use Zirconia-Toughened Alumina (ZTA). What unique microstructural mechanism gives ZTA its superior resistance to crack propagation compared to pure alumina?

A clinical trial comparing two total knee arthroplasty implants concludes there is no significant difference in survivorship at 10 years, though a true difference exists in the general population. Which of the following statistically explains this study's outcome?

A 40-year-old male bodybuilder feels a tearing sensation in his anterior elbow while lifting a heavy object. He has an abnormal Hook test. Operative repair is planned via a two-incision technique. Which complication is most uniquely associated with the two-incision technique compared to a single-incision anterior approach?

In the design of a linked, semiconstrained total elbow arthroplasty (TEA), what is the primary biomechanical function of incorporating a 'sloppy hinge' (allowing 5-10 degrees of varus-valgus laxity)?

A 68-year-old female with severe rheumatoid arthritis undergoes a primary linked semi-constrained total elbow arthroplasty (TEA). Post-operatively, what is the generally recommended permanent lifetime lifting restriction for the operated arm?

In the manufacturing of highly crosslinked polyethylene (HXLPE) for total joint arthroplasty, post-irradiation melting (raising the temperature above the melting point of 135 degrees C) is performed primarily to accomplish which of the following?

In total hip arthroplasty, the use of a ceramic femoral head articulating against a highly cross-linked polyethylene liner offers a specific tribological advantage over a cobalt-chromium head on polyethylene. What is the primary advantage?

Highly cross-linked polyethylene (HXLPE) is widely used in total hip arthroplasty to reduce volumetric wear. Which of the following mechanical trade-offs is most characteristically associated with the increased radiation dose required for high cross-linking?

A 75-year-old female with a previous total hip arthroplasty sustains a fall.

Radiographs show a periprosthetic fracture originating at the tip of the femoral stem. Comparison with prior radiographs reveals the stem has subsided by 1.5 cm. However, the surrounding proximal diaphyseal and metaphyseal bone stock remains adequate. According to the Vancouver classification, what is the most appropriate management?

A 70-year-old man presents with aseptic loosening 15 years after a total hip arthroplasty. Tissue retrieved during revision surgery shows numerous macrophages containing particulate debris. Which of the following is the primary cytokine released by these macrophages that drives the subsequent osteolysis?

A 55-year-old male develops a late periprosthetic joint infection after a total knee arthroplasty. Cultures yield Staphylococcus epidermidis. The chronicity of this infection is largely attributed to the organism's ability to produce a protective biofilm. Which of the following is the key component responsible for the initial adhesion phase to the implant in this process?