Intraoperative Periprosthetic Fractures Associated With Metacarpophalangeal Joint Arthroplasty

Purpose To assess the incidence of and identify risk factors for intraoperative periprosthetic fractures during primary and revision metacarpophalangeal (MCP) joint arthroplasty. Methods Through our institutional Joint Registry Database, we identified 818 MCP joint arthroplasties performed in 285 patients from 1998 to 2012, including 690 primary arthroplasties and 128 revision arthroplasties. Primary diagnoses included inflammatory arthritis (667), osteoarthritis (75), and posttraumatic arthritis (76). Periprosthetic fractures were identified through review of medical records. Results Intraoperative periprosthetic fractures occurred in 23 (3%) fingers (21 patients), including 19 primary and 4 revision arthroplasties. Twelve fractures required stabilization, 4 required only bone grafting, and 1 required both. The fractures occurred during broaching (12), implantation (10), or prior implant removal (1). Diabetes mellitus (DM), younger age, pyrocarbon implant insertion, and cementless fixation increased risk for intraoperative fracture. In particular, DM and the use of pyrocarbon implants significantly increased fracture risk. At 4 years (range, 1.3–10.2 y) average follow-up, no patient with intraoperative fracture had developed a subsequent fracture compared with 3 postoperative fractures in patients without intraoperative fractures. All fractures had healed by the time of the last follow-up. The 2- and 5-year implant survival rates were 96% and 80% in those with intraoperative fractures, respectively, which was not significantly different from those without an intraoperative fracture. When comparing patients with an intraoperative fracture with those without, there was an increased risk of postoperative MCP joint instability defined as implant dislocation. Patients with intraoperative fractures still had noteworthy improvements in their postoperative pain levels and pinch strengths. Conclusions Intraoperative fractures occurred in 3% of MCP joint arthroplasties, including 3% of primary and 3% of revision arthroplasties. Increased risk for fracture was associated with the use of pyrocarbon implants, cementless fixation, and DM. Although these fractures did not appear to adversely affect implant survival, they were associated with increased risk of postoperative instability. Type of study/level of evidence Prognostic III.