Outcomes Following Acute Metacarpophalangeal Joint Arthroplasty Dislocation: An Analysis of 37 Cases.

PURPOSE

There remains a paucity of information regarding the treatment outcomes of dislocation after metacarpophalangeal (MCP) joint arthroplasty. The purpose of this study was to assess the outcomes of surgical and nonsurgical treatment modalities of MCP arthroplasty dislocations.

METHODS

Of 816 MCP joint arthroplasties over a 14-year period, there were 37 (4%) acute MCP joint dislocations that required intervention by a health care professional. Implants involved included 28 nonconstrained implants including pyrocarbon (n = 17) and surface replacement arthroplasty (n = 11), and 9 silicone implants. The analysis included the treatment of dislocations after primary (n = 30) and revision (n = 7) MCP joint arthroplasty. Dislocation was defined as clinical and radiographic evidence of MCP joint prosthetic acute dislocation diagnosed and treated by a fellowship trained hand surgeon.

RESULTS

Etiologies underlying the dislocations included implant fracture (n = 6), component loosening (n = 2), and soft tissue deficiency (n = 29). Of the 37 dislocations, treatments included 14 nonsurgical (closed reduction, orthosis fabrication) all of which ultimately failed. Surgically, including some of the failed prior procedures, 18 soft tissue stabilization procedures and 21 revision arthroplasties were performed, with 6 that had failed soft tissue stabilization. The soft tissue stabilization procedures had a 28% success rate in achieving a stable MCP joint. Revision arthroplasty had a 71% success rate. Subgroup analysis showed an 86% success rate for silicone revisions and a 43% success rate with nonconstrained revisions, with 80% and 36% 5-year survival free of instability, for the 2 types of implants, respectively.

CONCLUSIONS

The treatment of MCP joint arthroplasty dislocation with revision to silicone implant appears to hold the most promise in achieving a stable MCP joint after an acute prosthetic dislocation.

TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.