Feasibility of contralateral trapezius transfer to restore shoulder external rotation: part I.

PURPOSE

We evaluated the feasibility of contralateral trapezius transfer to restore shoulder external rotation.

MATERIALS AND METHODS

The length of the lower trapezius and distance necessary for contralateral trapezius transfer were measured in 20 volunteers and directly in 12 cadavers. The average distances between the medial spine of the scapula and T12 (length of lower trapezius) and the spine to the greater tuberosity (distance for transfer) were measured with the scapula neutral, maximally protracted, and maximally retracted. In cadavers, the origin of the lower trapezius was detached, transferred to the contralateral greater tuberosity, and retracted to determine its effectiveness in external rotation and tension on the vascular pedicle.

RESULTS

In volunteers, the average difference between the length of the lower trapezius and the transfer distance was 19 mm in neutral. When the scapula was protracted and retracted, the difference was 79 and -49 mm. In the cadavers, the average transfer distance (in mm) was 290 ± 12, 365 ± 15, and 209 ± 25 in the neutral, protracted, and retracted positions, respectively. The average length of the lower trapezius (in mm) was 270 ± 10, 285 ± 12, and 258 ± 10 in the neutral, protracted, and retracted positions. The transfer was universally feasible when the scapula was partially retracted. Prolongation of the lower trapezius with lumbar fascia made the transfer possible in all scapular positions. Pulling on the transferred muscle resulted in contralateral shoulder external rotation without tension or impingement on the neurovascular pedicle.

CONCLUSION

Contralateral trapezius transfer to the infraspinatus insertion appears feasible and potentially effective in restoration of shoulder external rotation.