Complete versus Incomplete Footprint Coverage in Medium-Size Full-Thickness Rotator Cuff Tears

Purpose: This study aims to verify the preoperative factor that can affect the footprint coverage during arthroscopic rotator cuff repair in full-thickness medium-size cuff tear and the change of footprint coverage on magnetic resonance imaging (MRI) at postoperative 6 months. Methods: A total of 30 medium-size full-thickness rotator cuff tears were analyzed. They were classified into complete footprint coverage group (CC, n=19) and incomplete footprint coverage group (IC, n=11) by arthroscopic findings and immediate postoperative MRI findings. MRI was performed before the operation, 1 day after the operation, and 6 months after the operation. Preoperative MRI evaluated the size of the anteroposterior tear width (cm), length of retraction (cm), fatty infiltration, and muscle atrophy. Postoperatively, footprint coverage, fatty degeneration, and muscle atrophy were evaluated. We compared healing and change of fatty degeneration between two groups. Results: The healing rate was significantly increased in the CC group (complete/partial healing, 10/9) compared to the IC group (complete/partial healing, 6/5) (p 0.001). Six of 11 partial coverages (54.5%) were even improved to complete coverage at postoperative 6-month follow-up. However, the difference in footprint coverage did not affect the change of fatty degeneration at postoperative 6 months. Any change of fatty degeneration (FD) and initial FD of rotator cuff tendons were not correlated with healing (p 0.05).