The treatment of scapholunate (SL) ligament injuries is addressed by surgical procedures to stabilize the carpal joint. Open techniques include bone-ligament-bone transfers, tenodesis, partial fusions and carpectomies. Innovative procedures using wrist arthroscopy, offer minimally invasive fixation without full exposure of carpal bones; however, the success of the technique and its impact on the reduction on the range of carpal movement is as yet not well known. In this work, the performance of Corella tenodesis technique to repair the SL ligament is evaluated for a wrist type II by numerical methods. Human wrist can be classified based on the lunate morphology: type I for lunate that articulates with radius, scaphoid, capitate and triquetrum, and type II which has an extra surface to articulate with the hamate. A finite element model was constructed from CT-scan images, the model includes cortical and trabecular bones, articular cartilage and ligaments. Three scenarios were simulated representing healthy wrist, SL ligament sectioning and the Corella technique. The performance of the technique was assessed by measure the SL gap in dorsal and volar side as well as the SL angle to be compared to cadaveric studies. In intact position, the SL gap and the SL angle predicted by the numerical model is 2.8 mm and 44.8º, these values are consistent to the standard values reported in cadaveric experiments (2.0 ± 0.8 mm for SL gap and 45.8 ± 9.7 for SL angle). Virtual surgeries may help to understand and evaluate the performance of the techniques at clinical application.

Introduction

The use of larger femoral heads in Total Hip Arthroplasty has increased in order to reduce the risk of dislocation and to improve the range of motion of the joint. In 2003, within the UK, the “standard” head size of 28mm was used in 73% of all hip procedures, whereas by 2012, this figure dropped to 36%. Concerns regarding the impact of this increment in head size on the cement and bone stresses have arisen; however, this has yet to be clearly determined.