[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.