Introduction

The use of the dynamic hip screw is common practice for the fixation of intertrochanteric fractures of the femur. The success of this procedure requires accurate guide wire placement. This can prove difficult at times and can result in repeated attempts leading to longer operating time, multiple tracks and more importantly greater radiation exposure to both patient and operating staff. We hypothesised that rather than using the standard anterior-posterior projected image (Figure 1) of a proximal femur, rotating the intensifier image (Figure 2) so that the guide wire appears to pass vertically makes it easier to visualise the projected direction of the guide wire.

The Orthopaedic Competence Assessment Project (OCAP) is a validated system for assessment of competence in orthopaedics. OCAP materials are increasingly used in the NHS. Defence Orthopaedic trainees now deploy for 6 weeks on Operation Herrick.

The senior author used OCAP induction and assessment materials with the 3 three trainees assigned to him at the United Kingdom Medical Facility at Camp Bastion, Afghanistan. Mini-CV and ‘Military Trauma’ Knowledge and Procedure Profiles were provided and learning agreements signed at an initial meeting. Interim and final meetings took place to review progress and update Knowledge and Procedure Profiles. Procedure Based assessments (PBAs) were also attempted during the attachments.

Afghanistan was ideal for training due to a significant trauma caseload, close one-on-one supervision and no working time directives. The use of induction and assessment materials with which trainer and trainees were already familiar gave structure and focus to training on deployment and allows the benefit of the deployment to be demonstrated.

A research programme has been directed at the mechanism by which car occupants sustain ankle and hind-foot injuries. The severe injuries that are most associated with long term disability and high socio-economic cost have been investigated. Although seat belts and air bags have had a beneficial effect on injuries to most body regions including pelvic, femur and knee injuries, no protective effect has been demonstrated for below knee injuries. Only by understanding the mechanism of injuries to the leg below the knee will it be possible to design improved protection in the future.

Twenty three post mortem human surrogate (PMHS) limbs were impacted using a test set up that was developed to simulate the loading conditions seen in a frontal collision in 3 different positions – A, B & C. The impactor head (5cm x 10cm wide), was instrumented with an accelerometer and linear potentiometer. The impacting force was generated using a bungee-powered sled mounted on steel bearings. Three PMHS legs were tested In Position A (impactor head centred in line with the tibial axis), 9 PMHS legs were tested in Position B (impactor head centred on the anterior tibial margin) and 11 PMHS legs were tested in Position C (impactor head centred 2.5cm anterior to the anterior tibial margin). Active dorsiflexion was simulated through the Achilles tendon and prior to the application of Achilles tension a tibial pre-load (500 to1500N) was applied via a ‘jacking-plate’ applied to the proximal end of the tibia.

During impact testing, bone failure (fractures) occurred at impact loads of 5.7+/−1.9 kN (resultant tibial failure load 6.4+/−1.9 kN) and the following injuries were generated: 9 intra-articular calcaneal fractures; 1 talar neck and 2 talar body fractures; 3 intra-articular distal tibial (pilon) fractures; 2 malleolar fractures; 3 soft tissue injuries and in 3 cases there was no detectable injury. The impact test conditions were replicated with a Hybrid III leg in a first attempt at developing injury risk functions for the dummy.

This study has demonstrated the importance of preload through muscle tension in addition to the intrinsic properties of PMHS specimens in the generation of severe ankle and hindfoot injury.