Biomechanical evaluation of optimal humeral fracture fixation devices

The Glenohumeral joint poses one of the biggest challenges to an orthopaedic surgeon when compared to any other joint within the human body [1]. Finding the optimal treatment to suit each individual patient is crucial to his/her subsequent quality of life [2] but there is an urgent need to define more clearly the role and type of surgical intervention in the management of proximal humeral fracture [3]. This study aims to evaluate current humeral fixation techniques available to orthopaedic surgeons for their effectiveness at maintaining the integrity of the humerus across varied patient types, enabling full functional movement under physiological, cyclical loading and directly applied stresses. This is achieved using a finite element model of the Glenohumeral joint loaded with the in-vivo force mechanics of the joint. The FE model is validated against a mechanical test rig and current literature. Multiple tests are applied to the shoulder complex to investigate forces generated and effects on joint mechanics. These tests are based on activities of daily living with data collected using motion capture technology. As a result of the study it will be possible to make recommendations regarding the biomechanical fixation techniques of the proximal humerus for varying complexities of fracture, differing bone properties and populations in an attempt to find the optimal treatment to suit each individual patient. It also provides an opportunity to investigate how current fixation techniques are best used and look to advise on most effective applications.