Reoperation Rate in Thumb Metacarpophalangeal Fusions Using Nitinol Compression Staples.

PURPOSE: Nitinol technology offers a low profile means of applying compression across a fracture or fusion site. The objective of this study was to evaluate the rate of reoperation and fusion using nitinol staples for metacarpophalangeal (MCP) fusions of the thumb.

METHODS

This was a retrospective cohort study of thumb MCP fusions between March 2008 and June 2024 by a single surgeon. Fusions were performed with two nitinol staples: each beneath a collateral ligament flush with the bone. Demographic information, hand dominance, indication for surgery, length of follow-up, and reason for reoperation were collected.

RESULTS

Five-hundred and ninety-nine patients (503 women and 96 men) with 697 thumbs were candidates for analysis. Eighty-two thumbs had an isolated MCP fusion with bone graft; 615 thumbs had MCP fusions in combination with a carpometacarpal arthroplasty. For patients having carpometacarpal arthroplasty, an MCP fusion was performed to increase pinch strength in those with moderate-to-severe thenar atrophy. It was also performed to address MCP hyperextension greater than 30 degrees, MCP arthritis, or chronic collateral ligament instability. The mean age at the time of surgery was 64.4 years. Nine thumbs (1.3%) returned to surgery for painful or prominent hardware, and seven thumbs (1%) had reoperation for tendon adhesions at the MCP joint. The fusion rate was determined radiographically with bone consolidation across the joint and no lucency around the staples; all patients were fused between 4 and 12 weeks after surgery. The mean time for clinical follow-up was 9.6 months, whereas for reoperation was 31.3 months for hardware removal and 9.6 months for lysis of adhesions after the initial surgery. The minimum estimate of unexpected reoperation was 2.3%.

CONCLUSIONS

Metacarpophalangeal fusion with nitinol continuous compression staples was associated with a 100% fusion rate and a 2.3% reoperation rate for prominent hardware or adhesions.

TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.