TIP APEX DISTANCE, ARE WE GOOD ENOUGH IN A BUSY DISTRICT HOSPITAL?

Abstract

Introduction: Hip fractures are a massive problem in an ageing population with 7–21 million predicted world-wide by 2025. The stabilization of intertrochanteric fractures reduces morbidity, mortality and allows mobilization. The treatment of these fractures has evolved over the past 50 years to the Sliding hip screw and plate, and intramedullary devices Current evidence suggests that the SHS systems are superior in stable fracture patterns and intramedullary devices are superior in unstable fracture patterns such as reverse oblique fractures or subtrochanteric fractures. Accurate implant positioning will prevent failure and the associated morbidity and mortality. The most frequent failure is due to cut out of the screw through the femoral head due to poor positioning. Cut out is directly correlated with tip apex distance (TAD). A TAD < 25mm has been to shown to be key to preventing cut out irrespective of fixation device.

Aims: The aims of this audit were to review TAD in proximal femoral fractures stabilized with a SHS system at one hospital to ensure:

1. TAD is < 25mm.

2. To establish whether there was a correlation between TAD and surgeon grade or fracture type.

3. To establish positions of screws on both radio graphs.

4. To ensure SHS are used in the correct fracture types.

Results: Radiographs over a period of 1 year where reviewed. There were 86 cases of SHS fixation. 72% of cases were female (62:24). The mean age was 84(65 to 97). The mean preoperative delay before surgery was 4.5 range (0 –15). 13% of cases (11/86) had no postoperative radiographs either digitally or hard copies stored in the notes. The mean value of TAD was 20.8mm (Std dev 6.89). There was no correlation between fracture patterns and TAD, or surgeon grade and TAD. However there was a trend for higher TAD in inexperienced surgeons and in more complex fracture patterns.

The majority of cases were operated on by Registrars 67%, Staff grade 15%, Research fellows 9%, SHOs 6% and Consultant grades 3%. Registrars achieved Centre–Centre positions in 62% of cases with staff grade 47% of cases. The majority of SHS were performed for Types 2 and 4 according to Jensen & Michaelson classification. SHS implants were used in one subtrochanteric fracture and zero reverse oblique fractures. 21 cases had a TAD> 25mm and one of these has gone on to failure, requiring THR.

Conclusion: The mean TAD was within recommendations and there was no correlation between surgeon grade, fracture pattern and TAD. The positioning of screws corresponds closely to published data and remains acceptable as does the use of SHS devices. Both the preoperative delay and number of inadequate radiographs is unacceptable and needs improvement.