Central slip defect reconstruction utilizing partial ulnar side of flexor digitorum superficial tendon for chronic boutonniere deformity: A case report.

Background: Post-traumatic central slip injuries, resulting in boutonniere deformity, are a complex issue that can significantly impact hand function and quality of life. The deformity should be easily reducible in the acute phase, but if left untreated, it shortens the oblique retinacular ligament, leading to chronic contracture. This is a challenging issue in hand surgery, as chronic central slip defects cannot be sutured like other tendon. Various methods for reconstructing central slips have been discussed, but the best method for subacute or chronic injuries remains unclear. This case presents a case of chronic traumatic boutonniere deformity with central slip defect reconstruction.

Case Report: A 65-year-old male patient presented with swelling and boutonniere deformity on the digiti III of the right hand. The patient had previously fallen from a motorcycle, and the patient's right middle finger got was by a motorcycle six months ago. After the incident, the patient's right middle finger cannot be fully extended. The patient's right hand showed edema with flexion of the interphalangeal (PIP) joint and hyperextension of the distal interphalangeal (DIP) joint. The Range of Motion (ROM) of the PIP joint right middle finger was 45-110 degrees. The X-ray of the right hand AP/oblique showed no bone involvement in the deformity. The patient underwent central slip defect reconstruction utilizing the partial ulnar side of the flexor digitorum superficial tendon. A PIP joint extension splint was applied for 2 weeks. Active and passive exercise of the ROM of the PIP joint began after 2 weeks of PIP extension joint splinting. The patient's ROM of the PIP joint (0-90 degrees) significantly improved 1 month after surgery. The patient's ROM of the PIP joint returned to normal after 2 months after surgery. The function of the patient's right hand is evaluated with the DASH score, which improves significantly from 50 to 4.2.

Conclusion: Central slip defect reconstruction utilizing the partial ulnar side of the flexor digitorum superficial tendon is a reliable method for traumatic chronic boutonniere deformity and results in great functional outcomes after 2 months of follow-up. Central slip defect reconstruction utilizing the partial ulnar side of the flexor digitorum superficial tendon is a simple and cost-effective method compared to other methods.