Small Finger Snapping due to Retinacular Ligament Injury at the Level of Proximal Interphalangeal Joint: A Case Report

Abstract

Pathological snapping secondary to posttraumatic subluxation of the extensor tendon at proximal interphalangeal joint (PIPJ) of the finger is rare. Here, we want to describe a patient with snapping of the left small finger at PIPJ due to retinacular ligament injury. A 24-year-old man was admitted because of a 5-year history of a snapping sound in the left small finger. On examination, the radial side lateral band of the small finger was dislocated volarly at the level PIPJ with flexion of >50°, which was clearly felt over the skin. There was an obvious snapping sound at the time of dislocation. There was no specific radiographic abnormality. With the patient under regional anesthesia, exploration through a zigzag skin incision over the dorsum of the PIPJ revealed that the retinacular ligament complex was injured. We also found a partial tear in PIPJ capsule, through the incision of the injured retinacular ligament complex. We repaired the joint capsule and retinacular ligament complex with prolene 4-0. Postoperatively the small finger was immobilized in a below-elbow plaster splint with full extension of the fingers for 1 week, then dynamic splinting was advised for another 5 weeks and unrestricted full active motion was allowed at the 6th week. At the 6-month follow-up, the patient had regained full range of motion with no discomfort, and there was no sign of recurrence. We stress that when there is snapping over the dorsum of the PIPJ of the finger, the clinician should suspect rupture of the retinacular ligaments, especially in minor trauma patients. Primary repair of retinacular ligaments and dynamic splinting provided satisfactory results without recurrence in our patient.

FIGURE 1

Surgical exploration revealed a partially injured and attenuated retinacular ligament complex from the distal part of the lamina intertendineum between the central slip and the lateral band to the triangular retinacular ligament at the radial side (arrow).

FIGURE 2

Partially damaged PIPJ capsule seen through an incision in the attenuated retinacular ligament complex. PIPJ = proximal interphalangeal joint.

FIGURE 3

Damaged PIPJ capsule and retinacular ligaments were sutured with 4/0 prolene. PIPJ = proximal interphalangeal joint.

FIGURE 4

Postoperative dynamic splinting appearance.

FIGURE 5

(A, B) At Follow-up, 6 months later, he had regained a normal range of motion of the small finger without snapping.