Outcomes of restorative treatment for isolated trochlear cartilage lesions: a systematic review and meta-analysis

Background: Knee cartilage lesions can lead to debilitating symptoms, and between 6 and 15% of full-thickness cartilage lesions are found in the trochlea. Reviews summarizing the outcomes for isolated trochlear lesions are lacking. Therefore, the goal is to assess outcomes of various treatments for trochlear cartilage lesions. Methods: In April 2025, databases of PubMed, Embase, and Cochrane Library were searched for clinical studies reporting outcomes of advanced treatments of trochlear lesions (no patellar/bipolar lesions), minimum 1 year follow-up, and minimum 5 patients. Random effect models for various outcomes were used, and outcomes were reported with 95% confidence intervals (CI). Results: Nineteen studies (328 patients, mean age 34 years, mean follow-up 6.2 years, mean lesion size 4.2 cm2) were included. Most patients underwent (matrix-induced) autologous chondrocyte implantation (ACI/MACI) (228 patients) followed by osteochondral allograft (OCA) (48 patients). Most studies were level IV evidence without comparison. ACI/MACI had an estimated failure rate of 4.4% (1.6–9.2%), reoperation rate 21.7% (2.3–76.7%), postoperative IKDC 84.0 (79.0–89.0), Lysholm 91.8 (89–94.6), Tegner activity level 5.3 (4.6–6.1), and visual analog scale (VAS) pain 0.9 (0.3–1.5). For OCA, estimated failure rate was 2.1% (0.3–13.4%), and one study reported a reoperation rate of 21%. Estimated postoperative IKDC was 66.3 (54.6–78.1) and VAS pain 3.7 (0.8–6.6). Other treatments only had one study per treatment. Conclusions: In this study, ACI/MACI and OCA were the two most performed procedures with overall failure rates of less than 5% and satisfying patient-reported outcomes, although reoperation rates ranged widely. Patients reported clinically relevantly less pain and higher IKDC following ACI/MACI compared to OCA.