Background: Few studies on outcomes after anterior cruciate ligament (ACL) reconstruction (ACLR) have provided insight into the very long-term effects of this procedure. Purpose: To systematically review the outcomes, failure rate, incidence, and predictors of osteoarthritis (OA) for different ACLR techniques at a minimum 20-year follow-up. Study Design: Systematic review; Level of evidence, 4. Methods: A search of the PubMed, SCOPUS, and Cochrane databases was performed on June 2020 for studies of patients who underwent ACLR and had a minimum follow-up of 20 years. We extracted data on patient and surgical characteristics, patient-reported outcomes (Lysholm score, subjective International Knee Documentation Committee [IKDC] score, Knee injury and Osteoarthritis Outcome Score [KOOS], and Tegner score), clinical outcomes (IKDC grade, pivot shift, Lachman, and KT-1000 laxity), degree of OA (Kellgren-Lawrence, Ahlbäck, and IKDC OA grading), revisions, and failures. Relative risk (RR) of OA between the operated and contralateral knees was calculated as well as the pooled rate of revisions, failures, and conversion to total knee arthroplasty (TKA). Results: Included were 16 studies (N = 1771 patients; mean age, 24.8 years; mean follow-up, 22.7 years); 80% of the patients underwent single-bundle bone–patellar tendon–bone (BPTB) reconstruction. The average Lysholm (89.3), IKDC (78.6), and KOOS subscale scores were considered satisfactory. Overall, 33% of patients had “abnormal” or “severely abnormal” objective IKDC grade, 6.7% had KT-1000 laxity difference of ≥5 mm, 9.4% had Lachman ≥2+, and 6.4% had pivot shift ≥2+. Signs of OA were reported in 73.3% of patients, whereas severe OA was reported in 12.8%. The operated knee had a relative OA risk of 2.8 ( P < .001) versus the contralateral knee. Identified risk factors for long-term OA were male sex, older age at surgery, delayed ACLR, meniscal or cartilage injuries, BPTB autograft, lateral plasty, nonideal tunnel placement, residual laxity, higher postoperative activity, and postoperative range of motion deficits. Overall, 7.9% of patients underwent revision, and 13.4% of ACLRs were considered failures. TKA was performed in 1.1% of patients. Conclusion: Most patients had satisfactory subjective outcomes 20 years after ACLR; however, abnormal anteroposterior or rotatory laxity was found in nearly 10% of cases. The presence of radiographic OA was high (RR 2.8 vs uninjured knee), especially in patients with concomitant meniscal or cartilage injuries, older age, and delayed surgery; however, severe OA was present in only 12.8% of cases, and TKA was required in only 1.1%.

Purpose The aim of the study was to evaluate the long-term clinical results, reoperations, surgical failure and complications at a minimum of 20 year of follow-up of the first 8 medial CMI scaffolds implanted by a single surgeon during a pilot European Prospective study. Methods Seven (88%) out of 8 patients were contacted. The Cincinnati Score, VAS, and Lysholm score were collected. Moreover, magnetic resonance imaging (MRI) was performed on 4 patients at the last follow-up. Complications, reoperations and failures were also investigated. Results The average follow-up was 21.5 ± 0.5 years. One patient underwent TKA after 13 years from CMI implantation; a second patient underwent valgus high tibial osteotomy 8 years after the index surgery and another patient underwent anterior cruciate ligament hardware removal at 21 years of follow-up. At the final follow-up, 3 patients were rated as “Excellent”, 1 as “Good” and 2 as “Fair” according to the Lysholm score. The Cincinnati score and the VAS were substantially stable over time. The MRI showed a mild osteoarthritis progression in 3 out of 4 patients according to the Yulish score, and the CMI signal was similar to the mid-term follow-up revealing 3 cases of myxoid degeneration and 1 case of normal signal with reduced scaffold size. Conclusion The medial CMI is a safe procedure: satisfactory clinical results and a low failure rate could be expected even at a long-term follow-up. For this purpose, the correct indication as well as correcting axial malalignment and addressing knee instability at the time of the index surgery is mandatory. On the other hand, a mild osteoarthritis progression could be expected even after meniscus replacement. Level of evidence IV.