Severe Lateral Facet Patella Osteoarthritis Is Not Associated With Increased Failure at Mean 10 Years After Lateral Unicompartmental Knee Arthroplasty

Background: The purpose of this study was to determine if severe lateral patella facet osteoarthritis was related to lower survivorship and poor patient-reported outcomes following fixed-bearing lateral unicompartmental knee arthroplasty (UKA).

Methods: There were 61 patients who underwent a fixed-bearing, nonrobotically assisted, lateral UKA between May 7, 2003 and December 18, 2019 and met the inclusion criteria. The patello-femoral joint was examined intraoperatively for chondral damage prior to UKA implantation. Severe lateral facet patella osteoarthritis (LFPOA) was defined as Outerbridge grades 3 or 4 changes on the lateral facet. All patients completed subjective functional outcomes questionnaires and a clinical examination at a minimum of 4 years following UKA.

Results: Severe LFPOA was identified in 28 (46%) patients. At a mean follow-up of 10.9 years, there were no statistically significant differences in any Knee Osteoarthritis Outcomes Score (KOOS) subscale or Kujala scores between patients who had and did not have severe LFPOA. There was no statistically significant difference in the percentage of patients who achieved Patient Acceptable Symptom State for the KOOS subscale scores between groups. Mean survival in patients who did not have severe LFPOA was 16.6 years (95% confidence interval, 15.4 to 17.7) compared to 18.9 years (95% confidence interval, 17.6 to 20.2) in patients who had severe LFPOA (P = 0.62).

Conclusions: Severe LFPOA did not result in lower survival or inferior functional outcomes compared to patients who did not have severe osteoarthritis at an average 10-year follow-up after fixed-bearing lateral UKA.