Treatment of Patellofemoral Osteoarthritis After Total Knee Arthroplasty
For patellofemoral osteoarthritis developing after total knee arthroplasty, the evidence provided addresses only pre-TKA patellofemoral conditions, not post-TKA complications—this is a fundamentally different clinical scenario requiring revision surgery evaluation, not the conservative or primary surgical approaches described in the available guidelines.
Critical Context Gap
The provided evidence exclusively addresses:
- Primary patellofemoral pain in non-arthroplasty patients 1, 2
- Treatment of isolated patellofemoral OA before total knee arthroplasty 3, 4, 5, 6
- Outcomes when patellofemoral OA exists prior to TKA 7
None of these guidelines address patellofemoral osteoarthritis that develops AFTER total knee arthroplasty has already been performed.
Clinical Approach Based on General Orthopedic Principles
When patellofemoral osteoarthritis develops after TKA, you must systematically evaluate:
1. Determine the Mechanism
- Component malposition: Assess femoral and tibial component rotation, patellar tracking, and trochlear groove alignment on CT or radiographs
- Patellar management at index surgery: Was the patella resurfaced or retained? If retained, is there now severe cartilage loss?
- Extensor mechanism issues: Evaluate patellar height (Insall-Salvati ratio), quadriceps strength, and tracking abnormalities
- Polyethylene wear or loosening: Rule out component failure requiring full revision
2. Initial Conservative Management (Only if components are well-fixed and aligned)
- Targeted physiotherapy: Quadriceps strengthening and VMO activation (extrapolating from 1 principles, though not validated post-TKA)
- Activity modification: Reduce high-flexion activities that load the patellofemoral joint
- NSAIDs and ice: For symptomatic relief during acute flares
- Patellar taping or bracing: May provide temporary relief, though evidence is uncertain even in native knees 2
3. Surgical Options When Conservative Treatment Fails
If the patella was NOT resurfaced at index surgery:
- Secondary patellar resurfacing: This is the most straightforward option if components are otherwise well-positioned and the patellar bone stock is adequate
- Success rates are variable but can provide relief in appropriately selected patients
If the patella WAS resurfaced or components are malpositioned:
- Revision TKA: Required if there is component malrotation, patellar maltracking from femoral/tibial component issues, or polyethylene failure
- Isolated patellar component revision: Only if the patellar component is the sole problem (loosening, wear, malposition)
- Patellofemoral arthroplasty conversion: Generally not recommended after failed TKA; proceed to full revision instead
If all components are well-fixed but isolated lateral facet disease:
- Partial lateral patellar facetectomy: Has been described but has limited supporting evidence and cannot be systematically recommended 8
Key Pitfalls to Avoid
Do not apply primary patellofemoral pain guidelines (exercise therapy, foot orthoses, manual therapy 1, 2) to post-TKA patients—the biomechanics are entirely different with prosthetic components in place
Do not delay imaging evaluation: CT scan with rotational analysis is essential to identify component malposition that conservative treatment cannot address
Do not perform isolated procedures (like lateral release or facetectomy) without addressing underlying component malposition—this leads to persistent symptoms and potential complications
Do not ignore patellar height: Patella baja or alta significantly affects patellofemoral mechanics and may require tibial tubercle osteotomy during revision
Bottom Line
The evidence base for treating patellofemoral OA after TKA is absent from the provided guidelines. Clinical decision-making must prioritize identifying correctable mechanical factors (component malposition, patellar tracking, height abnormalities) through advanced imaging. If mechanical factors exist, revision surgery is required. If components are optimally positioned and the patella was retained, secondary resurfacing may be considered. Conservative measures borrowed from primary patellofemoral pain management have no validated role in the post-TKA setting and should only serve as temporizing measures while surgical evaluation proceeds.