arthroplasty
Patellofemoral Complications After TKA
advanced
6 min
20 marks
6 questions
Clinical Scenario
A 65-year-old woman presents with anterior knee pain 2 years after primary TKA for osteoarthritis. Pain is worse with stairs and rising from chairs. She reports an audible clicking from the patellofemoral joint. On examination, there is patellar crepitus, tenderness over the lateral patellar facet, and lateral patellar tilt. No effusion. Flexion is to 115° with a palpable clunk at 30° during active extension.
Skyline radiograph showing TKA with patellar component lateral subluxation and tilt. The patella is positioned lateral to the trochlear groove. Femoral component rotation should be assessed. No obvious patellar fracture or loosening visible.
Source: Patellar Resurfacing in TKA: Skyline View • PMC3378836 • CC-BY
Questions
Question 1 (3 marks)
Describe the radiographic findings and what additional imaging would you request.
Question 2 (4 marks)
What are the causes of patellofemoral complications after TKA?
Question 3 (3 marks)
How do you assess patellofemoral tracking intraoperatively during TKA?
Question 4 (4 marks)
What is patellar clunk syndrome and how is it managed?
Question 5 (3 marks)
What are your treatment options for this patient with maltracking and clunk?
Question 6 (3 marks)
What is the role of patellar resurfacing in primary TKA?
Exam Day Cheat Sheet
Must Mention
- •Femoral component IR = lateralized trochlea → maltracking
- •No-thumb test for intraoperative tracking
- •CT rotation protocol for diagnosis
- •Patellar clunk at 30-45° = fibrous nodule on anterior flange
- •Lateral release alone won't fix component malrotation
- •AOANJRR: resurfacing has lower revision rate
Common Pitfalls
- •Lateral release for rotational malposition
- •Not getting CT scan
- •Missing clunk syndrome diagnosis
- •Ignoring joint line elevation
- •Not assessing component rotation intraoperatively