Histopathology of Residual Tendon in High-Grade Articular-Sided Partial-Thickness Rotator Cuff Tears (PASTA Lesions)

PurposeThe purpose of this study was to examine the histopathologic features of the residual intact tissue of a partial articular surface tendon avulsion (PASTA) tear.MethodsIn 30 consecutive patients with PASTA lesions, biopsy specimens of the residual tendon were taken. The mean age was 60.4 years (range, 28 to 78 years). All tears were converted to full-thickness tears and arthroscopically repaired. None of the patients were overhead athletes. Samples were histopathologically examined and graded by use of a modified semiquantitative scale (between 0, normal appearance, and 21, most abnormal appearance). Data were analyzed by multiple regression analysis to estimate the effect of aging, smoking status, duration of pain, and steroid injections.ResultsDegenerative changes were evident in 28 of 30 cases (93%). The mean score on the modified semiquantitative grading scale was 10.5 (range, 3 to 16; SD, 2.6). Multiple regression analysis failed to show a statistically significant correlation between the score on the modified semiquantitative grading scale and aging, smoking status, duration of pain, or steroid injections.ConclusionsOver 90% of the macroscopically intact residual tendon tissues of the PASTA lesions showed moderate histopathologic degeneration.Level of EvidenceLevel IV, therapeutic case series.