Jonathan P. Braman, MD; Alicia K. Harrison, MD

Commentary Postoperative periprosthetic fractures of the humerus can be challenging for both the patient and the surgeon given that these fractures are difficult to treat and have high complication rates. The incidence of periprosthetic fractures after anatomic shoulder replacements has been reported to be 0.6%1. A recent series included four patients with a periprosthetic fracture after a reverse-geometry shoulder arthroplasty2, but we do not know of any other report or data on periprosthetic fractures after reverse shoulder arthroplasty. As the numbers of anatomic and reverse total shoulder replacements increase, orthopaedic surgeons will more commonly encounter these difficult fractures. Wright and Cofield proposed a classification system for periprosthetic humeral fractures3, although this system has not been validated and its ability to guide treatment has not been evaluated.
In their study, Andersen and colleagues described the operative treatment and surgical outcomes of thirty-six periprosthetic fractures after anatomic (nineteen) or reverse (seventeen) shoulder arthroplasty. Seventeen patients had a well-fixed prosthesis and were treated with open reduction and internal fixation (ORIF), whereas nineteen patients underwent revision arthroplasty because of a loose prosthesis and/or bone loss. In the ORIF group, all fractures healed, with a mean time to union of 6.8 months. In the group treated with revision arthroplasty, the original arthroplasty was reverse-geometry in sixteen cases and anatomic in three. Eighteen of the nineteen fractures in this group healed, with a mean time to union of 7.7 months. In both groups, shoulder motion at the time of the latest follow-up was similar to prefracture motion. The authors identified complications in fourteen (39%) of the thirty-six patients, which is consistent with rates reported in the literature. Campbell et al. reported a 43% complication rate after operative management of periprosthetic humeral fractures4.
Andersen and colleagues evaluated the validity of the classification system proposed by Wright and Cofield3. Three surgeons classified thirty of the thirty-six fractures according to the system of Wright and Cofield and, although the intraobserver reliability was good (mean kappa coefficient of 0.69), the interobserver reliability was poor (mean kappa coefficient of 0.37). Therefore, this classification system may not adequately direct periprosthetic fracture treatment.