Conservative tibial resection and vertical cut minimise risk of tibial plateau fracture after UKR - BASK

Tibial fracture is a known complication after unicompartmental knee replacement (UKR) [1]. Furthermore, some studies have indicated an increased risk of tibial fracture with cementless UKR [2]. Our aim was to identify surgical factors that contribute to fracture. We examined the influence of tibial saw cuts on the risk of fracture after cementless UKR, to determine if changes in tibial preparation could minimise the risk of fracture. The range and distribution of typical saw cut positions were measured from 23 right tibial Sawbones used as part of an instructional course. Sawbones were prepared by both experienced and unexperienced orthopaedic surgeons but all had received training on the operative technique. Measured parameters were; resection depth, excessive vertical cut anterior/posterior, excessive horizontal cut anterior/posterior, pin depth and pin angle. One hundred finite element models were then created where each parameter was assigned using a random number generator within its measured distribution, and the risk of fracture assessed. Results from a multiple linear regression model indicated that a greater resection depth and a more excessive posterior vertical cut significantly increased the risk of fracture after UKR. Based upon these results, a surgical technique and instrumentation for UKR which minimises inaccuracies in the vertical cut and promotes a more conservative resection depth would be recommended to minimise the risk of tibial plateau fracture after UKR.

[1] HG Pandit, DW Murray, CA Dodd, et al. (2007) Orthopedics 30: 28-31
[2] JB Seeger, D Haas, S Jager et al. (2012) Knee Surg Sports Traumatol Arthrosc 20: 1087-1091