Implants, Prosthetics and Joint Replacement MCQs

Orthopedics · 26 free questions with answers & explanations.

1. A 72-year-old woman with severe bilateral osteoarthritis of the hip undergoes total hip replacement. Six months postoperatively she has a painful, warm, erythematous hip with raised CRP and elevated ESR. Aspiration reveals 50,000 WBC/mm³ with 90% neutrophils. The most likely diagnosis is:
2. In total hip replacement, the most common bearing surface combination that provides the best wear characteristics and lowest revision rate in young, active patients (<55 years) as per current guidelines is:
3. A 68-year-old woman undergoes cemented total knee replacement. Which complication is most directly related to the use of bone cement (polymethylmethacrylate — PMMA) during implant insertion?
4. Which of the following is the SINGLE most important modifiable risk factor for periprosthetic joint infection (PJI) after total knee replacement?
5. A 65-year-old man requires total hip replacement for osteoarthritis. For uncemented (cementless) femoral components, the PRIMARY mechanism of biological fixation is:
6. The Singh index on plain X-ray is used to assess osteoporosis. Which grade indicates threshold (borderline osteoporosis) where Ward's triangle trabecular group has disappeared but principal tensile and compressive groups are intact?
7. The commonest cause of failure (loosening) of total hip replacement in the long term is:
8. In total hip arthroplasty (THA), the 'safe zone' (Lewinnek zone) for acetabular cup placement describes an abduction angle of ___° and anteversion of ___°, with ±10° tolerance:
9. Metal-on-metal (MoM) hip bearings were largely abandoned due to which specific complication that is unique to this bearing surface?
10. In the context of cemented hip arthroplasty, the Barrack-Harris grading of cement mantle quality grades the cement technique. A Grade B cement mantle is defined as:
11. A 72-year-old man undergoes cemented total hip replacement. Six weeks postoperatively he has acute right groin pain and fever. X-ray shows no implant loosening. CRP 120 mg/L, ESR 90. Hip aspiration grows Staphylococcus aureus. Which of the following is the MOST appropriate treatment based on timing and classification?
12. A 68-year-old patient with a DePuy ASR metal-on-metal hip resurfacing implant presents with groin pain, a 'soft tissue mass' around the hip, and serum cobalt level of 14 µg/L (normal <2 µg/L). MRI shows a large fluid collection with local soft-tissue destruction. What is the DIAGNOSIS and recommended management?
13. A cephalomedullary nail (PFNA or Gamma nail) is preferred over a sliding hip screw (DHS) for which intertrochanteric fracture pattern? Select the MOST specific indication.
14. In total hip arthroplasty (THA), the acetabular component is placed at a target inclination (abduction angle) and anteversion. The 'safe zone' described by Lewinnek is:
15. In cementless total hip arthroplasty, initial stability of the acetabular cup depends on 'press-fit.' The recommended under-reaming practice to achieve adequate press-fit is:
16. In a total knee arthroplasty, failure due to polyethylene insert wear leading to progressive osteolysis is caused by which mechanism primarily?
17. In the Dorr classification of femoral canal morphology relevant to cementless THA, a Dorr Type C canal is characterised by which morphological feature and its implication for stem choice?
18. During cemented total hip replacement, the Charnley design uses a stainless-steel femoral head with a high-density polyethylene acetabular cup. The main advantage of cementless (press-fit) over cemented fixation in a 65-year-old active patient is:
19. In intramedullary nailing of femoral shaft fractures, the 'reamer-irrigator-aspirator' (RIA) system is used to reduce which SPECIFIC complication compared to conventional reaming?
20. A Dynamic Hip Screw (DHS) is the implant of choice for which type of intertrochanteric hip fracture?
21. During cemented total hip arthroplasty, antibiotic-loaded bone cement is commonly used. Which antibiotics are most commonly incorporated into PMMA cement and what is the mechanism of their local activity?
22. Cementless total hip arthroplasty relies on press-fit fixation and osseointegration. Which surface coating/modification most effectively promotes bone ingrowth into the acetabular cup?
23. A patient with a metal-on-metal total hip arthroplasty (MoM THA) presents 5 years post-surgery with hip pain, a soft-tissue mass on MRI, and elevated serum cobalt (18 μg/L) and chromium (9 μg/L) levels. What is this complication and the appropriate management?
24. In total knee replacement, the posterior cruciate ligament (PCL) is either retained (CR-TKR) or sacrificed (PS-TKR). In which clinical scenario is PCL-retaining TKR relatively contraindicated?
25. The dynamic hip screw (DHS) is contraindicated in which fracture pattern and why?
26. Which of the following bearing combinations in total hip arthroplasty has the LOWEST volumetric wear rate?