Clinical results and failure rates after meniscal allograft transplantation and autologous chondrocyte implantation: a systematic review.

Background: Meniscal allograft transplantation (MAT) and autologous chondrocyte implantation (ACI) are well-established procedures. However, evidence regarding the safety and efficacy of their combined application remains inconclusive. Thus, the present systematic review aimed to comprehensively evaluate the existing literature on clinical outcomes after combined MAT and ACI.

Methods: A comprehensive search of clinical studies reporting on clinical outcomes after combined MAT and ACI was performed across three databases in accordance with the review protocol. Key demographic data, surgical technique, knee-specific patient-reported outcome measures, failure rates, and reoperation rates were extracted from eligible studies and analyzed. Risk of bias was assessed using the Methodological Index for Non-Randomized Studies (MINORS).

Results: The search yielded 246 studies, 9 of which satisfied inclusion and exclusion criteria, comprising 155 patients undergoing combined MAT and ACI at an average age of 36.1 years. The mean follow-up duration was 5.3 years (2.0-12.9 years). Clinical outcome measures improved across all studies (with one exception in a single outcome measure); statistical significance was shown in six out of seven studies reporting significance analysis. International Knee Documentation Committee (IKDC) scores were reported by four studies, showing an average improvement of 22.0 points. Lysholm scores showed an average improvement of 20.0 points across five studies. Of five studies comparing combined procedures with isolated procedures, one comparative study and one literature comparison reported inferior outcomes after combined surgery, while one subgroup analysis and two literature comparisons found comparable outcomes. Failure rates ranged from 0.0% to 52.6%, with significant methodological heterogeneity. The mean reoperation rate was 35.0% across seven studies.

Conclusions: Combined MAT and ACI leads to meaningful improvements in clinical outcomes, with notable failure and reoperation rates. While some studies suggest outcomes may be comparable or inferior to isolated procedures, only one study directly assessed this. As such, definitive conclusions cannot be drawn. Combined MAT and ACI can be considered as a viable option in select patients, but realistic expectations must be ensured.