Progressive Thinning of Autologous Fascia Lata Graft Is Associated With Graft Retear After Superior Capsular Reconstruction: A 5‐Year Magnetic Resonance Imaging Study

PURPOSE: To investigate serial changes on magnetic resonance imaging (MRI) in superior capsular reconstruction grafts classified as healed according to the Sugaya classification over a 5-year follow-up period, with graft thickness as the primary outcome, and to evaluate humeral head migration (HHM), clinical outcomes, the longitudinal correlation between MRI-based graft changes and clinical outcomes, and the diagnostic accuracy of MRI using magnetic resonance arthrography (MRA). METHODS: This retrospective comparative study reviewed patients with massive irreparable rotator cuff tears who underwent superior capsular reconstruction between January 2017 and December 2019 and had a minimum follow-up of 5 years. Patients with concomitant tendon transfer, nonfascia lata grafts, or incomplete follow-up were excluded. The patients were divided into 2 groups (graft intact or graft retear group) according to the Sugaya classification of MRI. MRI was performed at 1 week, 6 months, and 1, 2, and 5 years postoperatively to assess changes in graft thickness and HHM. Clinical outcomes were evaluated using the visual analog scale, Constant score, American Shoulder and Elbow Surgeons score, forward elevation, and external rotation, both preoperatively and at the same postoperative intervals. MRA was performed in patients with persistent symptoms despite an intact-appearing graft on conventional MRI to further assess graft integrity and validate MRI findings. RESULTS: A total of 58 patients were included in this study, of whom 33 were categorized into the graft retear group and 25 into the graft intact group. In the graft intact group, the graft thickness at the humeral attachment, midsubstance, and glenoid attachment progressively decreased over time, with a significant reduction observed at 5 years compared with 1 week postoperatively. HHM significantly increased beginning at 1 year and continued to rise through the 5-year follow-up. Linear mixed-effects analysis showed a significant association between greater graft thickness and better outcomes in the visual analog scale (β = -0.45), American Shoulder and Elbow Surgeons score (β = 3.48), forward elevation (β = 6.06), and external rotation (β = 3.07). Among 10 patients who underwent MRA because of persistent symptoms, 8 (80.0%) were found to have a graft retear despite MRI-based classification as intact. CONCLUSIONS: Graft thinning and superior HHM were observed on MRI despite apparent graft integrity, and these findings were associated with worse clinical outcomes. MRA showed a high incidence of graft retears in these cases. LEVEL OF EVIDENCE: Level III, retrospective comparative study.