[Comparative study of the anatomic and clinical effect of Weaver or subtotal subscapularis tendon section in Latarjet procedure].

PURPOSE OF THE STUDY: The aim of this work was to compare the anatomic and functional effect on the subscapularis muscle of two ways of sectioning its tendon during Latarjet procedure: complete vertical section and Weaver section (partial section of the lower third preserving the upper part of the tendon).
MATERIAL AND METHODS: We compared two series (eight-year interval) of patients comparable for age, gender, form of instability, type and level of sports activity. Twenty-nine patients underwent complete vertical section (group 1) and 30 Weaver section (group 2). All were reviewed with minimum four year follow-up. The clinical analysis involved strength of internal rotation, the maximal hand-back distance, and the Constant and Duplay scores. The radiographic analysis was coupled with computed tomography in 46 patients (23 in each group). Loss of subscapularis muscle thickness compared with the non-operated side was noted as was the Bernageau fatty infiltration stage.
RESULTS: No recurrent dislocation was noted in either group. There were six cases of nonynion in group 1 and seven in group 2. The Gerber was positive in five patients in group 1 and zero in group 2 (P=0.01). Loss of internal rotation strength between the operated and healthy side, expressed in percentage, was 48.4% for group 1 and 17.9% for group 2 (P<0.0006). In group 1, the fatty infiltration stage of the subscapularis muscle was: stage 0 (n=3), stage 1 (n=11), stage 2 (n=3), stages 3 and 4 (n=6). In group 2, these stages were: stage 0 (n=21), stage 1 (n=1), stage 1 (n=2) and zero stage 3 and 4 (P<0.0001). DISCUSSION: The Latarjet operation remains the reference procedure for anterior stabilization of the shoulder joint. The choice of the incision technique for the subscapularis muscle tendon remains a subject of debate. Recent studies have demonstrated the importance of subscapularis muscle trophicity to obtain a good mid- and long-term clinical outcome. We have ourselves demonstrated elsewhere that complete section of the subscapularis tendon leads to secondary tears and subsequent fatty degeneration.
CONCLUSION: Our study demonstrates that Weaver section in the Latarjet procedure enables placing the bone block in conditions equivalent to those achieved with total section while preserving better trophicity of the subscapularis muscle.