Four-Corner Fusion with Locking Dorsal Circular Plate versus Headless Compression Screws: A Clinico-Radiological Comparative Study

Introduction Four-corner fusion is a technique for the treatment of carpal advanced collapse. It consists of scaphoid excision and arthrodesis of the lunate, triquetrum, hamate, and capitate bones. This can be accomplished with different kinds of osteosynthesis. In the first reports of the use of a circular plate, poor outcomes are described, with high rates of non-union, which decreased in later studies, which highlight certain aspects of the surgical technique. Objective To report our experience with four-corner fusion with the use of a dorsal locking plate (Xpode, Trimed Inc., Santa Clarita, CA, US), and compare it with another traditional fixation method (3.0-mm headless compression screws [HCSs], Synthes, Slothurn, Switzerland), with an emphasis on union, an assessment of the fincitonal outcomes, and the presence of complications. Material and Methods A comparative study of two prospective series of patients operated on through two fixation techniques for four-corner fusion using autologous bone graft from the iliac crest. The first group of patients, evaluated between 2010 and 2012, underwent osteosynthesis with 2 HCSs, with a minimum follow up of 18 months. The second group, evaluated between 2011 and 2014, underwent osteosynthesis with a dorsal locking plate, with a minimium foloow up of 12 months. The patients were operated on by four different surgeons in four centers. The patients were evaluated with radiographs to establish the presence of union and the time it took to occur. In case of doubt, union was confirmed through a computed tomography (CT) scan at 8 weeks postoperatrively. We also assessed the range of motion, the presence of complications, and function through the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire and a grip strength score. Results We achieved a union rate of 100% in both groups at similar times. In the dorsal locking plate group, we obtained better full range of motion, particularly in wrist extension, which was statistically significant (p = 0.0016), as well as lower DASH scores, which was also statistically significant (p = 0.0066). Complications were only present in two patients in the HCS group. Conclusion Both techniques are valid and reproducible for the treatment of wrists with scapholunate advanced collapse (SNAC) and scaphoid non-union advanced collapse (SLAC). Based on the outcomes, with the Xpode plate, the patients presented better ranges of motion and DASH scores; therefore it may be an excellent fixation option in the open four-corner fusion surgical technique. The entry point and configuration of the HCS are fundamental variables to analyze. The union rate of 100% obtained in the present study contrasts with the high rates of non-union reported in the literature published in the early 2000s.