Long-term follow-up of allograft reconstruction of segmental defects of the humeral head associated with posterior dislocation of the shoulder.

The purpose of this study is to report the long-term follow-up result of allograft reconstruction of segmental defect of the humeral head associated with posterior dislocation of the shoulder. Six men underwent operative management of defects of the humeral head involving 40% of the articular surface, following posterior dislocation of the humeral head. The period of time between dislocation and surgery ranged from 7 to 8 weeks. The defect in the head was filled with an allogeneic segment of humeral head contoured to restore the spherical shape. All the patients returned to their occupation 4 months later. All the cases were evaluated clinically and by radiographs and computed tomography (CT) scan at a mean of 122 (96-144) months after the operative procedure. Three men had no complaints of pain, instability, clicking or catching, whereas three had pain, clicking, catching and stiffness. The three patients with good clinical result showed also good radiographic result. The computed tomography (CT) confirmed incorporation of the allograft and no osteoarthrosis. Another patient had a good clinical and radiographic result until the eighth postoperative year. At 8-year follow-up examination, this patient developed shoulder osteoarthrosis and he had pain and stiffness. He needed an arthroplasty 10 years after the operation. The other two patients developed collapse of the graft and osteoarthrosis that were yet evident at 4-year follow-up. These patients required a shoulder arthroplasty 8 years after the procedure. We conclude that the treatment of segmental defects of the humeral head associated with posterior dislocations of the shoulder by allograft reconstruction has a good long-term follow-up result in 50% of the patients.

[Posterior locked shoulder fracture-dislocation: anatomical resconstruction of reverser Hill-Sachs lession]. / Fractura-luxación posterior inestable del hombro: reconstrucción anatómica de la lesión de Hill-Sachs invertida.

The posterior instability of the shoulder only represents 4% of the shoulder instabilities. For the diagnosis, the antero-posterior, transtoracic and axilar radiographic projections are recommended. The inverted Hill-Sachs lesion is a fracture caused by compression of the antero-medial part of the humeral head during the posterior dislocation. Its treatment results, at least, controverted. Choosing the treatment of these lesions one of the main factors is the size of the defect in the humeral head. When it is smaller than 20%, the simple reduction usually is enough. Between 20-40%, we can opt for a transposition of the subescapular insertion to the bony defect (technique of MacLaughlin) or the anatomical reconstruction of the head by means of the fixation of an allograft. The transposition of the subescapular´s tendon carries a reduction of the internal rotation by medializing its insertion, for this reason, we opted for the anatomical reconstruction with allograft of femoral head that reestablishes the muscular balance. The shoulder artroplasty is elective when bony defects are bigger (>40-50 % of the articulation surface). We present the case of a 32 year-old patient, with the antecedent of convulsive crisis. Clinically he suffered intense pain with functional impotence and elastic limitation for the external rotation in left shoulder. The radiographic studies evidenced an instable posterior fracture-dislocation with inverted Hill-Sachs lesion associated that involved the 30% of the articular surface. The patient was surgically treated, opting for a reconstructive technique for humeral head. After six months, the range of motion is almost symmetrical with regard to the healthy shoulder, without any clinic of instability.