The isolated subscapularis tendon tear. Arthroscopic and open repair

Objective. Arthroscopic or open reconstruction of isolated subscapularis tendon tears with the use of suture anchors to restore the glenohumeral function and joint biomechanics. Indications. Traumatic full-thickness tears, chronic tears with a functional deficit or decentration of the humerus head, anterosuperior rotator cuff insufficiency, symptomatic reruptures after prior arthroscopic or open surgical procedures. Contraindications. Frozen shoulder, atrophy > grade II (Thomazeau) or fatty infiltration > grade III (Goutallier/Fox) of the muscle, high-grade omarthrosis. Surgical Technique. Diagnostic arthroscopy and careful tendon release. If the inferior edge of the rupture is reliable visible and the tendon-mobilisation works proper, the repair is performed arthroscopically. The footprint is decorticated lightly and 1-4 suture anchors (depending on the lesion-size) are placed from inferior to superior. Knots are tied starting from caudal in a modified Mason-Allen technique (alternative: single or double mattress stitches) with a slipknot and three half hitches in opposite directions. In case of larger tears, a double-row technique for better reconstruction of the trapezoidal footprint is performed. For open reconstruction, a deltopectoral approach is used to reattache the tendon in an analogous fashion. Results. Arthroscopic or open repair of isolated subscapularis tendon tears (Fox type II-IV) was performed in 35 patients. The Constant score increased significantly after 36 m, with no difference between these two groups. The majority of subscapularis tests were postoperatively negative, 6% in both groups showed a rerupture. A symptomatic period of > 6 m prior to the operation and a high grade atrophy and fatty infiltration of the muscle was correlated with poorer results.