We reviewed 39 patients with displaced three- and four-part fractures of the humerus. In 21 patients (group A) we had used an anatomical prosthesis for the humeral head and in 18 (group B) an implant designed for fractures. When followed up at a mean of 29.3 months after surgery the overall Constant score was 51.9 points; in group A it was 51.5 and in group B 52.4 points. The subjective satisfaction of the patients was assessed using a numerical rating scale and was similar in both groups. In group A complete healing of the tuberosities was found in 29% and 50% in group B. Partial integration was seen in 29% of group A and in only one patient in group B, while resorption was noted in 43% of group A and 44% of group B. The functional outcome was significantly better in patients with complete or partial healing of the tuberosities (p = 0.022). The specific trauma prosthesis did not lead to better healing of the tuberosities. The difference in clinical outcome obtained by the two designs did not reach statistical significance

Fractures of the proximal humerus can lead to malalignment of the humeral head, necrosis and post-traumatic osteoarthritis. In such cases surface replacement might be a promising option.

A total of 28 shoulders with glenohumeral arthritis subsequent to a fracture underwent surface replacement arthroplasty of the humeral head in patients with a mean age of 60 years (35 to 83). On the basis of the inclination of the impacted head, post-traumatic arthritis was divided into three types: type 1, an impacted fracture of the head in an anatomical position (seven cases); type 2, a valgus impacted fracture (13 cases); type 3, a varus impacted fracture (eight cases). The outcome was measured by means of the Constant score.

According to the Boileau classification of the sequelae of fractures of the proximal humerus, all 28 patients had a final result of intra-capsular category 1. The mean Constant score for the 28 shoulders increased from 23.2 points (2 to 45) pre-operatively to 55.1 points (20 to 89) at a mean of 31 months (24 to 66) post-operatively. Valgus impacted fractures had significantly better results (p < 0.039).

Surface replacement arthroplasty can provide good results for patients with post-traumatic osteoarthritis of the shoulder. Their use avoids post-operative complications of the humeral shaft, such as peri-prosthetic fractures. Further surgery can be undertaken more easily as the bone stock is preserved.