Patellofemoral Osteoarthritis Severity and Outcomes in Total Knee Arthroplasty

A retrospective study presented at the American Academy of Orthopaedic Surgeons 2025 Annual Meeting found that patients with more severe preoperative patellofemoral osteoarthritis (OA) reported superior knee-specific outcomes following total knee arthroplasty (TKA) without patellar resurfacing.

While conventional wisdom often suggests that greater patellofemoral OA may lead to inferior outcomes, findings from this cohort challenge that assumption, demonstrating improved knee-specific patient-reported outcome measures (PROMs) in patients with more severe preoperative OA.

Researchers conducted a retrospective review of 872 consecutive primary TKAs performed without patellar resurfacing. Of these, 667 (76%) underwent an aggressive lateral patellar facetectomy. Preoperative patellofemoral OA severity was graded using established scoring systems for the medial and lateral patellar facets, assessing severity, marginal osteophytes, and joint space narrowing. Radiographic measurements of patellar tilt and displacement were also obtained. PROMs were analyzed at the latest available follow-up, with a mean duration of 15.2 months (range, 1-85 months), and statistical significance was set at P ≤ .05.

The patient cohort was 63% female, with a mean age of 65 years and a mean BMI of 35 kg/m². Those with Osteoarthritis Research Society International osteophyte grades ≥ 2 on the medial patellar facet exhibited greater improvement in Knee Injury and Osteoarthritis Outcome Score for Joint Replacement from baseline (P = .047), reported their knees as "sometimes or always" feeling normal more frequently (89% vs 80%, P < .001), and had greater overall satisfaction (82% vs 76%, P = .093) compared with those with lower grades. Additionally, patients who underwent a lateral patellar facetectomy demonstrated significantly reduced postoperative patellar tilt compared with those who did not (P = .004).

"Contrary to modern anecdotal contention, patients with more severe preoperative radiographic patellofemoral arthritis, particularly in the medial facet, demonstrated superior knee-specific PROMs than patients with selectively unresurfaced patellae after modern primary TKA,” the study authors concluded. “In addition, the use of an aggressive lateral patellar facetectomy may optimize postoperative patellar tracking, which may reduce patella-related complications."

Reference:
Gunderson ZJ, Sokrab R, Luster T, Buller LT, Deckard ER, Meneghini RM. Patellofemoral OA severity is not correlated to PROMS in TKA with selective patella resurfacing. Presented at: American Academy of Orthopaedic Surgeons; March 10-14, 2025; San Diego, CA. Accessed March 6, 2025. https://submissions.mirasmart.com/AAOS2025/Itinerary/PresentationDetail.aspx?evdid=198