Influence of sex on the outcome of autologous chondrocyte implantation in chondral defects of the knee.

Background: Sex-specific outcomes have been reported in anterior cruciate ligament reconstruction as well as in osteoarthrosis progression, but there are currently no related published data on autologous chondrocyte implantation (ACI). The present prospective study was performed to investigate sex-dependent differences in the results after ACI.

Hypothesis: The clinical and magnetic resonance imaging (MRI) results after ACI of the knee are influenced by the patient's sex.

Study Design: Cohort study; Level of evidence, 2.

Methods: The midterm clinical and MRI results of a cell-based fibrin-polymer graft for the treatment of full-thickness cartilage defects were evaluated preoperatively and 6, 12, and 48 months after surgery in 52 patients (male:female ratio, 25:27; average age, 35.6 years). Depending on the sex and the location of the defects (femoral condyles, n = 32; patellofemoral compartment, n = 20), patients were assigned to 4 different groups. Baseline clinical scores were compared with follow-up data by paired Wilcoxon tests for the Lysholm score and the International Knee Documentation Committee (IKDC) scoring system. Sex-specific differences were evaluated with the Mann-Whitney U test. The MRI evaluation was performed with the Henderson score at final follow-up.

Results: Clinical scores improved in all groups over the whole study period (P < .05). Compared with female patients, male patients achieved significantly better results in the Lysholm score at all time intervals and in the IKDC score at 6 and 12 months after surgery (P < .05). In a subgroup analysis, female patients with patellar defects had the worst results in both clinical scores. With the available number of patients, MRI evaluation at 48 months after surgery revealed no significant difference in defect fill between male and female patients (P > .05). The Pearson correlation coefficient between both clinical scores and the MRI parameters of defect fill and cartilage signal was significant (P < .05).

Conclusion: Autologous chondrocyte implantation is a promising treatment option for full-thickness cartilage defects of male and female knee joints. Female patients with patellar defects have worse prognostic factors.