BACKGROUND: Interest in biological augmentation for improving bone-tendon interface (BTI) healing after arthroscopic rotator cuff repair (ARCR) is growing. Dermal fibroblasts, known for collagen synthesis similar to tenocytes, have shown effectiveness in BTI healing in chronic rotator cuff tear (RCT) models in rabbits. However, no human clinical trials have been conducted. PURPOSE: To evaluate the clinical efficacy of autologous dermal fibroblasts (ADFs) for BTI healing after ARCR in patients with full-thickness RCTs >
2 cm. STUDY DESIGN: Randomized controlled trial
Level of evidence, 2. METHODS: A total of 86 patients were prospectively enrolled and randomized into 2 groups: an additional ADF injection between the bone and tendon during ARCR (ADF group) or ARCR alone (control group). A skin biopsy from the buttock was performed to obtain ADFs, which were cultured for approximately 4 weeks before surgery. ARCR was standardized to the double-row suture bridge technique to reduce the heterogeneity in different repair methods. The primary variable for evaluating ADF efficacy was the retear rate using magnetic resonance imaging at 6 months postoperatively. Secondary variables included range of motion, the American Shoulder and Elbow Surgeons score, the Constant score, and the Simple Shoulder Test score at baseline and at 6 and 12 months postoperatively. RESULTS: Overall, 13 patients dropped out because of a subscapularis tendon tear, loss to follow-up, or the withdrawal of consent (7 in the ADF group and 6 in the control group). The retear rate was significantly lower in the ADF group (5.6% [2/36]) than in the control group (24.3% [9/37]) ( CONCLUSION: ADF application into the BTI during ARCR significantly decreased the retear rate in patients with full-thickness RCTs >
2 cm. Therefore, an ADF injection could be a promising biological supplement to enhance BTI healing in these patients. However, clinical outcomes showed no significant difference between the 2 groups at 6 months and 1 year postoperatively.