Proximal scaphoid hemiarthroplasty for the treatment of post-fracture avascular necrosis of the proximal pole

Introduction

The scaphoid is the most frequently fractured carpal bone. Most of its surface is covered by articular cartilage, which limits the space for the entrance of nutritious vessels. This leads to a precarious irrigation, especially at its proximal pole. A fracture further impairs bloodflow, which may lead to delayed union, nonunion, or even avascular necrosis of the proximal fragment. The proximal scaphoid hemiarthroplasty is one of the techniques available to treat the scaphoid proximal pole osteonecrosis. This part of the bone is substituted by a pyrocarbon implant that aims to maintain proximal carpal row kinematics and prevent carpal collapse, minimizing the risk for symptomatic osteoarthrosis. The goal of our study was to evaluate the long-term results of proximal scaphoid hemiarthroplasty for posttraumatic avascular necrosis of the scaphoid's proximal pole.

Materials and methods

Twelve patients who underwent this procedure were identified, and the average follow-up time was 6.5 years (range 5–8 years). All patients were male, with a mean age of 39 years (ranging from 28 to 55). In 8 patients the non-dominant limb was the one affected. The procedure was carried out through a dorsal approach and all patients were subjected to the same rehabilitation protocol. Functional results were determined using the QuickDASH and Mayo Wrist Score.

Results

There were no immediate postoperative complications such as infection or dislocation of the implant. All patients presented with peri-implant osteolysis at follow-up. None of the patients was forced to abandon their previous professional activity, even though 50% required some type of adaptation necessary at their workplace. The average functional capacity was, according to the Mayo Wrist Score, of 67.5 points (range 50–80), corresponding to a “Satisfactory” degree of function. From the application of the QuickDASH resulted an average disability of 25 (range 3–47.7).

Discussion

All patients mentioned as having the biggest disability with working with, or carrying, heavy objects. The results of this series are in line with previously published studies about this technique.

Conclusion

Hemiarthroplasty with a pyrocarbon implant is a safe technique for the treatment of post-fracture avascular necrosis of the scaphoid pole. This technique allowed for a satisfactory functional result at a mean follow-up of 6.5 years.