Degenerative changes after posterior cruciate ligament reconstruction are irrespective of posterior knee stability: MRI-based long-term results.

Abstract

Posterior cruciate ligament reconstruction (PCLR) is advocated to prevent an early onset of osteoarthritis. We hypothesized that posterior instability after PCLR correlates with degenerative changes. MRIs of 42 (12 female/30 male; 39 ± 9years) patients were enrolled with a minimum 5-year follow-up (FFU) after PCLR. In addition, 25 contralateral and 15 follow-up MRIs (12months after baseline) were performed. Degenerative changes were graded using WORMS. Posterior tibial translation (PTT) was measured using posterior stress radiographs. Outcome parameters included WORMS/cartilage subscore for the whole joint, patellofemoral (PFJ), medial (MFTJ), and lateral femorotibial joint (LFTJ). Final follow-up was 101 (range 68-168) months. WORMS reached 41.5 [18.5-56.8]. Regional WORMS for PFJ was significantly higher than MFTJ and LFTJ. Cartilage subscore yielded 7 [2.8-15]. MFTJ and PFJ were significantly higher than LFTJ. Primary outcome parameters were significantly higher than the contralateral knee (P < 0.0001) and significantly increased within 12months (P = 0.0002). There was a significant correlation between the intraoperative degree of cartilage injury and WORMS (P < 0.0001 with r = 0.64) and between the number of previous surgery and the cartilage subscore (P = 0.03 with r = 0.32). Meniscal surgery led to a significantly higher WORMS (P = 0.035). Combined risk models revealed that women below the mean age had significantly lower WORMS (P = 0.001) and cartilage subscores (P = 0.003). Patients undergo degenerative changes after PCLR, which are significantly higher compared to the contralateral knee. These occur predominantly at PFJ/MFTJ and are irrespective of posterior stability. Concomitant meniscus/cartilage injuries and a high number of previous surgeries are further risk factors.