Relationship between hematoma-like tissue on the footprint and structural outcome of arthroscopic rotator cuff repair with a transosseous technique

BACKGROUND: We have tried to create hematoma over the footprint site at the end of arthroscopic rotator cuff repair (ARCR) surgery, expecting to apply biochemical effects of the platelet-related factors. The purpose of this study was to investigate the presence of hematoma-like tissue (HLT) on postoperative magnetic resonance imaging, and to evaluate the relationship between the HLT and the structural outcomes of ARCR. MATERIALS AND METHODS: Twenty-five patients were reviewed with a mean age at surgery of 69.8 years (range, 52-85 years). Postoperative magnetic resonance imaging was performed at 1 week, 6-8 weeks, and >6 months postoperatively. Structural outcomes for the repaired cuff and thickness of HLT were evaluated on coronal T2-weighted images. Signal intensity of HLT was evaluated on coronal T2-weighted fat-suppressed images as the ratio compared to supraspinatus tendon intensity (HLT/SSP ratio). RESULTS: Structural outcomes showed Sugaya type 1 in 12 shoulders, type 2 in 4, and type 3 in 9. HLT thickness was significantly thicker at 1 week and 6-8 weeks postoperatively in Sugaya type 1 patients than in type 3 patients (1 week; P = .014, 6-8 weeks; P < .001). HLT/SSP ratio gradually decreased (at 1 week; 1.9 ± 0.7, 6-8 weeks; 1.6 ± 0.6, >6 months; 1.2 ± 0.5), and differed significantly between >6 months and both 1 week and 6-8 weeks (P < .001 each).