[Predictors of Knee Replacement Following Meniscal Tear Arthroscopy: a 7-Year Risk Prediction Model]

The aim of this study was to analyze the outcomes of knee arthroscopy (KA) for degenerative meniscal tears in relation to early total knee arthroplasty (TKA) in the elderly population. The study focused on identifying the factors that influence the need for TKA within seven years after previous arthroscopic partial meniscectomy (APM).

A total of 526 patients older than 64 years who underwent APM between January 1, 2010, and December 31, 2015, were included in the study. The patients were divided into three groups according to age. Specific patient data were extracted from the hospital information system. Preoperative, intraoperative, and postoperative data were collected according to a predefined protocol.

A total of 118 patients (22.4%) underwent TKA within seven years after KA, with a mean time to TKA of 35.5 months. Notably, up to 30% of patients required TKA within one year of their initial KA. The mean age at the time of TKA was 72.2 years. Women had a higher risk than men (24.4% vs. 19.2% men; p = 0.195). When all factors were analyzed, postoperative pain (OR = 4.17; 95% CI: 2.03-8.553), varus knee alignment (OR = 2.45; 95% CI: 1.20-5.01), and BMI (OR = 1.11; 95% CI: 0.02-1.20) were significant predictors of TKA. When considering only preoperative factors, varus alignment on radiographs (OR = 2.39; 95% CI: 1.21-4.71), a higher radiographic grade of knee osteoarthritis (OR = 1.85; 95% CI: 1.12-3.07), and BMI (OR = 1.09; 95% CI: 1.01-1.17) were the strongest predictors of early TKA. Among intraoperative/postoperative findings, the presence of medial chondropathy confirmed during KA (OR = 2.07; 95%CI: 1.52-2.83) and postoperative pain (OR = 5.02; 95% CI: 2.75-9.17) were the only significant predictors.

This study highlights the risk of TKA in elderly patients undergoing APM. Previous studies have cautioned against performing this procedure in older patients, yet the optimal treatment for symptomatic knees with degenerative meniscal tears remains uncertain. Several factors may influence the progression of knee osteoarthritis in these patients, with knee biomechanics and pre-existing osteoarthritis being the most critical. Both can potentially be addressed with appropriate knee osteotomy, a procedure that has recently been shown to be effective in patients with knee osteoarthritis. Interestingly, age itself did not increase the risk of TKA in our study. In conclusion, our retrospective analysis showed that more than one-fifth of patients undergoing KA for degenerative meniscal tears may require TKA within seven years. In addition, preoperative varus knee alignment, advanced knee osteoarthritis, and higher BMI were identified as the strongest risk factors, suggesting that KA should be indicated with caution in such patients.