Factors influencing the outcome of autologous chondrocyte implantation: a systematic review.

Autologous chondrocyte implantation (ACI) is an effective method of treatment of chondral defects of the knee. ACI outcomes are influenced by patient-, knee-, and lesion-specific factors. We compiled subject-level data from current studies on ACI and quantitatively analyzed this data set for associations between patient-, knee-, and lesion-specific factors and the outcome of ACI surgery. A systematic review of studies investigating ACI treatment outcomes in the knee was performed. Only studies that published subject-level data were included. Data on patient and lesion characteristics, as well as clinical outcome scores, were collected. Thirteen studies (305 defects) were included in this review. These studies showed that ACI treatment improves clinical outcomes in different patient populations. However, subject-specific variables such as patient age, gender, body mass index, duration of preoperative symptoms, as well as defect size and location were not associated with International Knee Documentation Committee score or visual analog scale score changes (p > 0.05 for all). Covariate analysis showed that patient age was related to symptom duration prior to surgery (p = 0.009). ACI surgery has been shown to improve outcomes in patients with chondral lesions of the knee. Despite evidence in the literature showing that multiple patient-, knee-, and lesion-specific factors may influence treatment outcomes, our review shows that these factors, solely, do not affect outcomes. However, together, they may synergistically affect outcomes.