Volar Plate Fixation for Extra-Articular Proximal Third Phalangeal Fractures of proximal phalanx: A Comparative Study of Tendon-to-Bone Distances and Functional Outcomes

Abstract

Background Phalangeal fractures, especially those of the proximal phalanx, account for approximately 25% of hand and wrist fractures. Plating is generally associated with severe tendon-related complications and unsatisfactory hand function. Recently, volar plating has been used to fix intra-articular fractures at the base of the proximal phalanx, and it has been reported to result in excellent finger motion and grip strength. We proposed that volar plating has a lower risk of tendon irritation compared to dorsal plating due to the larger tendon-to-bone distances on the volar side. The purpose of this study was to: 1) present the surgical outcomes of 9 cases of extra-articular fractures in the proximal third of the proximal phalanx treated with volar plating, and 2) compare the tendon-to-bone distances between the volar and dorsal sides of the proximal phalanx. Methods A prospective cohort of nine patients with proximal third fractures of the proximal phalanx was recruited. Each patients underwent an MRI of the healthy middle finger on either hand to evaluate the distances between the flexor and extensor tendons and the proximal phalanx. The distances were measured using our in-built measurement tool. Demographics including age, gender, dominant hand, diabetes, smoking, affected fingers were collated. Complications such as extensor lag, wound infections, delayed wound healing, malunion, non-union, delayed union and tendon rupture were recorded. Total active motion (TAM) was also calculated by addition of ROM at the metacarpophalangeal joint, proximal interphalangeal joint and distal interphalangeal joint. Results Nine patients (6 males, 3 females) with fractures of the proximal third of the proximal phalanx were included in this study. All nine patients achieved good bone healing and recovery of functional range of motion (235 ± 24 degrees) after 1 year of follow-up. No major complications were reported, except for one patient with delayed wound healing. The measurements of the distances between the bone and the flexor and extensor tendons were reported as follows. There were significant differences in the average distance from the tendons to the bone cortex for the middle (volar: 1.07 cm, dorsal: 0.21 cm) and distal (volar: 2.96 cm, dorsal: 0.64 cm) third of the proximal phalanx (p = < 0.001). Conclusions The increased tendon-to-bone distance on the volar side may be an important factor contributing to the excellent hand function observed with volar plating in the treatment of proximal phalangeal extra-articular fractures