A NEW INTERNAL-FIXATION DEVICE FOR PROXIM AL HUMERAL FRACTURES

Purpose of the study The authors describe a new internal fixation devi ce, and report on 17 proximal humeral fractures managed with this tech nique. Material and methods The fracture patterns, using Neer's classi fication were:9 displaced three-part fractures, 4 displaced four-part fractures and 4 anterior fracture dislocations (mean age of the patien ts : 70 years). The device is a two-part titanium device. The humeral component has a long vertical stem cemented in the humeral shaft; and a short proximal portion set at an angle of 135 degrees on the stem, w ith a neck and a Morse taper cone. The other part is a crown-shaped st apple, whose base is a perforated disk with a central Morse taper sock et. The rim of the crown has five prongs which, together with the cent ral socket, are impacted in the cancellous bone of the humeral head. T he taper of the humoral component is inserted into the central socket of the stapple to provide fracture fixation. Tuberosities are reattach ed to the shaft with non absorbable sutures. Results Mean follow-up wa s 29 months. The global ratings were as follows: 4 excellent results, 6 good results, 4 fair results, 3 poor results. Mean active forward fl exion : 100 degrees, and mean active external rotation 22 degrees. Aft er exclusion of the 4 fracture-dislocations, the global rating became: 4 excellent results, 5 good results, 3 fair results, 1 poor result. M ean active forward flexion : 110 degrees and mean active external rota tion : 31,5 degrees. There were no case of avascular necrosis in 13 pa tients. Complications requiring surgery occurred in one case: an upper protrusion of the stapple which required replacement of the stapple b y a prosthetic humeral head Other complications included: 2 asymptomat ic partial protrusions of the stapple, 2 complete and two partial avas cular necrosis in fracture-dislocations. Discussion Except for the fra cture-dislocations our device confers several major benefits. The hume ral head is preserved. Typical problems associated with joint replacem ent (dislocations, loosening, glenoid degeneration) are avoided. Humer al head conservation enhances healing of the tuberosities. Fixation co uld always be obtained, regardless of the complexity of the fracture p attern, An hemiarthroplasty (e.g. in case of avascular necrosis) is po ssible by the modular design of the device.