[Scapulohumeral arthrodesis for non-neurological shoulder: a study of 8 cases]

Scapulohumeral arthrodesis is mainly used for the treatment of sequelar injury after brachial plexus palsy. Indications are however controversial and limited to patients with non-neurological shoulders. We report a series of eight shoulder arthrodeses performed on non-neurological shoulders in order to determine and detail the current role of this procedure.

The series included eight patients, five men and three women, mean age 47 years (23-87). The dominant side was operated on in two patients and the non-dominant side in six. Seven patients had had at least one shoulder procedure prior to arthrodesis. Arthrodesis was performed for foreign body reaction on a tendon prosthesis in one patients, posttraumatic head necrosis in two, off-centered degenerative joint disease with full thickness rotator cuff tear in three, and multi-directional instability on degenerative joint disease in two. Arthrodesis was performed via a posterior approach in all patients but one using screw fixation associated with external fixation left in place for 2.5 months on average.

All patients except one were satisfied with the outcome (basically because of pain relief). Mean active motion was 75 degrees flexion, 65 degrees abduction (arthrodesis at 20 degrees flexion, 25 degrees abduction and 30 degrees internal rotation). Two groups were identified to analyse the absolute Constant score. The score improved 16 points (from 24 to 40) in the group of patients without instability (pain score improved from 3 to 13) and decreased 14 points (from 66 to 52) in the group with instability (due to decreased motion, the mean motion score declining from 38 to 14). Complications included one radial palsy, one nonunion, and one gravity edema of the upper limb.

Shoulder arthrodesis is more than a salvage method to reduce pain and gain stability. The objective should be to recover useful function (hand-mouth, hand-perineum, brachio-thoracic function). It should be used when prosthetic arthroplasty is not possible (infectious arthritis, advanced degenerative disease in young subjects, loss of glenoid bone stock, failure after treatment of multidirectional instability with degenerative disease). Shoulder arthrodesis still has rare indications because of the predictability of sustained outcome.