Abstract
Purpose: Collapse or necrosis of the head of the humerus after fracture of the proximal humerus can be an indication for shoulder arthroplasty. The poor results classically reported have led to a search for factors predictive of the anatomic and functional outcome after arthroplasty for fracture sequelae.
Material and methods: Among the 221 Aequalis prostheses implanted for the treatment of sequelae after fracture of the proximal humerus, 137 (62%) developed post-traumatic avascular osteonecrosis of the humeral head with a deformed callus of the tuberosity. Head tilt was in a valgus position in 83 shoulders and in a varus position in 54. Mean age was 61.49 years. The initial fractures were subtuberosity fractures in 20% of the cases, three-fragment fractures in 32%, and cephalobituberosity fractures with four fragments in 48% of the cases.Twenty-five percent of the patients had undergone initial osteosynthesis. The rotator cuff was repaired in 4.5%, and two osteotomies of the less tuberosity and four osteotomies of the greater tuberosity were performed at implantation. Pre- and postoperative clinical and functional outcomes were assessed with the Constant score and a function index composed of eleven usual movements.
Results: Mean follow-up was 44 months (24–104), with a mean 42° gain in anterior elevation and a 29° gain in external rotation. The gain in the Constant score was +32 points (mean score 61), and +43% with the weighted score. The four subscores (pain, motion, activity, force) improved two-fold. Analysis of the eleven usual movements demonstrated recovery in 88% of the patients. The subjective satisfaction index was 86%. The mean Constant score improved significantly more after total arthroplasty (67 points) than after humerus prosthesis (55 points). Complications (per- or postoperative mechanical problem, infection, neurological disorder) or the need for revision were unfavourable elements.
Discussion: Deformation and deviation of the tuberosities, especially the greater tuberosity, often leads to osteotomy during the implantation procedure. In this series, osteotomies were exceptional and functional outcomes showed that deviated tuberosities could be preserved without having an unfavourable effect on functional prognosis. Much on the contrary, the absence of a tuberosity osteotomy simplified the operative procedure and produced much better functional outcome than observed in earlier studies. The rate of complication for secondary prosthetic implantation is not negligible (15%) and a simplified procedure without osteotomy is a useful criterion. Furthermore, rehabilitation may be started earlier after implantation when it is not retarded by osteotomy bone healing, found to be an unfavourable factor.
Conclusion: Implantation of a shoulder prosthesis after collapse or necrosis of the head of the humerus after proximal fracture with varus or valgus impaction has provided good functional outcome without tuberosity osteotomy since the deformation of the tuberosity is generally well tolerated.
The abstracts were prepared by Docteur Jean Barthas. Correspondence should be addressed to him at Secrétariat de la Société S.O.F.C.O.T., 56 rue Boissonade, 75014 Paris.
