Outcomes Following Multiligament Knee Injuries: A Systematic Review of Studies With a Minimum 7-Year Follow-up

Background: Multiligament knee injuries (MLKIs) are complex and present significant challenges in achieving optimal long-term outcomes. This systematic review aims to evaluate clinical and functional results, complications, and return-to-sport rates following MLKIs, with a minimum 7-year postoperative follow-up. Purpose: To report the long-term clinical and functional outcomes after MLKIs at a minimum 7-year follow-up. Study Design: Systematic review; Level of evidence, 4. Methods: A comprehensive literature search was performed in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines, identifying 16 studies encompassing 730 knees. Extracted data included patient-reported outcomes, return-to-sport rates, osteoarthritis development, complications, reoperations, and revision procedures. Due to study heterogeneity, a qualitative analysis was conducted. Results: Postoperative patient-reported outcomes demonstrated considerable variability, with mean scores generally modest at long-term follow-up (reported in 13 studies). Return-to-sport rates, available from 8 studies, ranged from 60.4% to 85%. Osteoarthritis progression was reported in 7 studies, with the proportion of patients exhibiting Kellgren-Lawrence grades 3 or 4 at final follow-up ranging from 12% to 71.7%. Reoperation rates were reported in 7 studies and ranged from 1.7% to 34.3%, most commonly for manipulation under anesthesia and lysis of adhesions due to postoperative stiffness. Conversion to total knee arthroplasty was reported in 6 studies, with rates ranging from 0% to 10.9%. Repeat ligamentous surgery varied across 7 studies, with posterior cruciate ligament reconstruction failures most frequently reported. Conclusion: Outcomes >7 years after treatment of MLKIs demonstrate meaningful restoration of function and sport participation but remain tempered by significant rates of osteoarthritis and reoperation for stiffness. Advances in surgical technique and early rehabilitation have improved results in contemporary cohorts. Continued prospective evaluation using standardized protocols is essential to enhance joint preservation and patient quality of life. Registration: PROSPERO (CRD 420251078013).