Prospective study of hammertoe correction with an intramedullary implant

Background: Operative correction of a hammertoe deformity is often accomplished by excision of the articular surface of the proximal interphalangeal joint (PIP) and fixation across the joint. This study aimed to prospectively evaluate clinical and radiographic outcomes of hammertoe operative correction utilizing an internal implant and assess its ability to maintain postoperative alignment.

Methods: Twenty-nine patients (53 toes) with a painful rigid hammertoe deformity were prospectively enrolled and operatively treated with resection arthroplasty of the PIP joint and fixation with an implant. Five patients were lost to follow-up, and 24 patients (42 toes) returned at an average of 12 months for final clinical and radiographic evaluation. All patients were evaluated pre- and postoperatively by AOFAS and Visual Analog Pain Scale (VAS) scores. On physical exam, the location and magnitude of the deformity, callosities, and digit circumference were recorded. Radiological parameters evaluated were digital alignment, successful union, implant position, and bone reaction.

Results: All patients reported satisfaction at final follow-up, with an average improvement of AOFAS score from 52 (range, 24-87 points) to 71 (range, 42-95 points) points. The mean VAS pain score improved from 5 points (range, 2 to 10) preoperatively to 1 point (range, 0 to 5) postoperatively. Of patients, 87% reported an ability to return to their preoperative activities without limitations. Regarding digital alignment, there were no recurrent deformities or transverse plane deformities; 1 toe presented with a minor digital rotational deformity at final follow-up. Postoperative radiographs indicated 100% of proximal interphalangeal (PIP) joints with good alignment, and 81% demonstrated bony union.

Conclusion: Our results suggest that utilization of an internal implant for hammertoe correction was safe and provided acceptable alignment, pain reduction, and improved function at final follow-up.

Level of evidence: Level IV, case series.