Focused Extracorporeal Shock Wave Therapy for Painful Delayed Union or Nonunion of Fractures of Interphalangeal Coalition.

Background: Interphalangeal coalition is characterized by fusion of interphalangeal joint between the middle and distal phalanges. Interphalangeal coalition fractures often result in delayed union or nonunion. The purpose of this study was to evaluate the results of focused extracorporeal shock wave therapy (ESWT) for painful delayed union or nonunion of fractures of the interphalangeal coalition.

Methods: The study group consisted of 9 patients (9 feet) diagnosed with painful delayed union or nonunion due to persistent pain and no tendency toward bony union for at least 3 months after the interphalangeal coalition fracture on plain radiographs between 2021 and 2023 were included. The mean age was 51.3 years (23-64). Focused ESWT was performed in all patients. The mean time from the date of injury to the start of ESWT was 16.1 weeks (12-15). ESWT was performed every 2 weeks, with each session consisting of 3000 impulses (0.15-0.25 mJ/mm²). Plain radiographs were used to confirm bone union, and visual analog scale (VAS) scores were used for pain assessment.

Results: Complete bony union was documented in all 9 patients. The application of focused ESWT was performed a mean of 2.7 times (2-4), and the mean duration from the initiation of treatment to the confirmation of bony union was 7.4 weeks (3.6-12.7). In all cases, the symptoms of swelling and pain were alleviated. The VAS scores exhibited significant improvement, with the mean VAS score decreasing from 3.8 (2-6) before ESWT to 0 after the achievement of union (P < .001).

Conclusion: In this small cohort, all patients with painful delayed union or nonunion of fractures at the interphalangeal coalitions achieved complete bony fusion after focused ESWT. Moreover, bony union was observed within 2 months of ESWT initiation. These findings suggest that focused ESWT may be a valuable treatment option for painful delayed union or nonunion of interphalangeal coalition fractures.

Level of evidence: Level IV, case series.