Paper 03: The effect of patellofemoral chondrosis on outcomes following meniscus root repair

Objectives: Meniscal root repair has been shown to improve symptoms and protect against the development of progressive knee arthritis by restoring more normal distribution of weightbearing forces. While advanced tibiofemoral chondrosis is known to negatively affect root repair outcomes, there is a paucity of literature describing the impact of concomitant patellofemoral chondrosis (PFC). The objective of the current study was to evaluate the outcomes of meniscal root repair in patients with and without advanced PFC.
Methods: This single-center retrospective study included patients who underwent isolated posterior medial meniscal root repair (PMMR) between June 2011 and February 2023, with a minimum follow-up of 2 years. Based on intraoperative arthroscopic findings, patients were stratified into two groups: those with patellofemoral chondrosis (PFC), defined as Outerbridge (OB) grade >=3 and a non-PFC group (< grade 3). Clinical outcomes, including meniscal re-tear, conversion to unicompartmental or total knee arthroplasty (UKA/TKA), and revision meniscal surgery, were obtained through chart review. Patient-reported outcomes (PRO) included the KOOS-12, IKDC subjective score, and return to sport status..
Results: A total of 115 patients were included, 67 patients with PFC (mean age 55.0 years; 82.1% female) and 48 non-PFC controls (mean age 52.0 years; 66.7% female). There were no significant differences in demographics or medial/lateral tibiofemoral Outerbridge grades between groups. The mean follow-up duration was 6.2 years for the PFC group and 5.7 years for the non-PFC group.At final follow-up, there were no significant differences between groups in KOOS-12 Pain, Function in Daily Living, or Quality of Life subscales, as well as IKDC scores or return to sport rates (all p>0.05). Rates of PASS, MCID, and SCB achievement were also similar. Re-tear rates (PFC: 11.9% vs non-PFC: 8.3%) and revision meniscal surgery rates (PFC: 1.5% vs non-PFC: 4.2%) were similar between groups.However, the PFC group demonstrated a significantly higher rate of conversion to unicompartmental or total knee arthroplasty (UKA/TKA) compared to the non-PFC group (14.9% vs 2.1%, p = .021). The average time to conversion for the PFC group was 3.89 +- 3.46 years (7 TKA/3 UKA), and there was only one conversion in the non-PFC group at 7.78 years (UKA).
Conclusions: Patients with and without patellofemoral chondrosis at the time of medial meniscus root repair that did not go on to UKA/TKA had comparable PROs and CSOs at final follow-up. However, a significantly higher rate (almost seven-fold) of conversion to unicompartmental or total knee arthroplasty (UKA/TKA) was observed in patients with PFC, suggesting that while short- to mid-term functional outcomes may be preserved, advanced PFC may predispose patients to earlier progression of joint degeneration and the need for arthroplasty. This highlights the importance of considering patellofemoral joint status when counseling patients on expected outcomes following meniscus root repair.