Inside-out Volar Portal of Arthroscopy of Proximal Interphalangeal Joints: A Cadaver Study

The application of arthroscopy in the proximal interphalangeal joints can avoid scar development and joint contracture. However, conventional arthroscopic techniques are difficult to apply to the palmar side of the joint. This study aimed to explore the feasibility and safety of the inside-out volar portal arthroscopic technique for the proximal interphalangeal joint, elucidating a new portal technique for the inspection and treatment of small joints.

We performed the inside-out palmar portal arthroscopic technique on 10 cadavers. The distances between portals and important tissues were measured in both the extended (0°) and 90° flexed positions of the proximal interphalangeal joint.

The full cohort demonstrated sufficient safety distances from portals to proper digital vessels and nerves, flexor digitorum tendons, and extensor digitorum tendons in all the fingers. Statistically significant differences were found in the distances to the ulnar interosseous vein, ulnar interosseous nerve, and ulnar flexor tendon among the four fingers. Specifically, the mean values were higher in the index and middle fingers compared to the ring and little fingers. Additionally, the measurements were similar between the ulnar and radial sides, suggesting that the inside-out volar portals can be established on either side of the proximal interphalangeal joint.

The findings demonstrate the feasibility of the inside-out volar portal arthroscopic technique. This study provides a new portal selection for proximal interphalangeal joint arthroscopy.

Surgical techniques for the proximal interphalangeal should consider the pathology of palmar structures to ensure optimal treatment. This study suggests that the inside-out volar portal arthroscopy of the proximal interphalangeal joint is a feasible technique for joint diseases.