Periprosthetic humeral fractures after shoulder arthroplasty.

BACKGROUND: Currently, there is little information concerning periprosthetic humeral fractures after shoulder arthroplasty. Therefore, we reviewed our experience with these fractures to determine the results of treatment, the risk factors for periprosthetic fracture, and the rates of reoperation.

METHODS: Between 1976 and 2001, nineteen postoperative periprosthetic humeral fractures occurred among 3091 patients who had undergone shoulder arthroplasty at our institution. Sixteen patients had a complete series of radiographs and were included in this study. The average time from the arthroplasty to the fracture was forty-nine months. Seven patients had severe osteopenia. Twelve fractures occurred at the tip of the prosthesis; of these, six extended proximally (type-A fractures) and six did not (type-B fractures). Three fractures occurred distal to the implant and extended into the distal humeral metaphysis (type-C fractures). One fracture occurred in the proximal metadiaphyseal region because of osteolysis.

RESULTS: Six fractures healed after an average of 180 days of nonoperative treatment. Five fractures were treated operatively after an average of 123 days of unsuccessful nonoperative treatment. The remaining five fractures had immediate operative treatment. All sixteen fractures healed. One patient required multiple operations over a period of three years before union was achieved. With the exclusion of this patient and one other patient who received a custom prosthesis, the average time between the first operative procedure and union was 278 days.

CONCLUSIONS: Our data do not clearly indicate the need for operative treatment of type-A fractures unless the humeral component is loose. A trial of nonoperative treatment may be considered for well-aligned type-B fractures that are associated with a well-fixed humeral component; however, operative intervention should be considered for type-B fractures that have not progressed toward union by three months. If the component is well fixed, open reduction and internal fixation may be performed. If the component is loose, revision with a long-stem component is recommended. For type-C fractures, a trial of nonoperative treatment is recommended.