Over Half of Patients Progress to Cartilage Restoration After Initial Cartilage Biopsy in a Military Population

Purpose To evaluate the rate of matrix‐induced autologous chondrocyte implantation (MACI) after cartilage biopsy in a military population. Methods A retrospective review was conducted of all patients who underwent a cartilage biopsy at 2 large regional military health centers between January 2021 and May 2023. Patients 17 years of age or older who underwent an index biopsy more than 2 years prior to chart review were eligible for inclusion. The primary outcome was progression from cartilage biopsy to MACI. Secondary outcomes included complication rates and lesion characteristics. Continuous variables were compared using an unpaired t‐test, and categorical variables were analyzed using Fisher's exact test. Results A total of 56 patients were included in the study, with a mean age of 31.9 ± 8.3 years. Thirty‐five (62.5%) patients were male, and 50 patients (89%) were current or former military service members. Two patients underwent bilateral knee biopsies, yielding 58 knees, with 32 proceeding to MACI for a 55.2% implantation rate. Multifocal chondral defects were noted in 59% of knees. The most common defect location was the patella (64%). Reoperation occurred in 22% of cases after MACI. Conclusions In this military cohort, just over half of patients who underwent an initial cartilage biopsy proceeded to MACI within 2 years. Level of Evidence Level IV, therapeutic retrospective case series.