Abstract
Introduction and Aims
Peritrochanteric femur fractures are common and impose major costs on the healthcare system. A fixed angle sliding hip screw is the principle method of treatment, but the rate of mechanical failure associated with these devices can be high; the usual mechanism being the collapse of the neck shaft angle leading to extrusion of the screw from the femoral head, commonly known as “cutout”. Many variables contribute to the risk of cutout, however there is substantial evidence that the “Tip Apex Distance” (a single number that summarises the position and depth of the lag screw on anteroposterior and lateral radiographs after controlling for magnification) is the single best predictor of risk of failure. There is a strong statistical relationship between an increasing tip apex distance (TAD) and the rate of cutout. Specifically, a TAD of 25 mm or less significantly reduces risk of failure. The aim of our study is to assess levels of compliance with a maximum TAD of 25 mm in peritrochanteric femur fractures treated with Dynamic Hip Screws and IM Nails.
Methods
We retrospectively measured the TAD of 45 patients who had undergone DHS or IM nails in the previous 6 months.
Results
21/28 of DHS were within 25 mm as opposed to 15/17 of IM nails.
Discussion
In this cohort, 75% and 88% of patients respectively had a tip apex distance which complied with best evidence to reduce risk of failure. In total, 20% of patients fell outwith acceptable limits. It was surmised that the IM nails would have greater tip apex distances due to fractures generally being more complex, however it is suggested that this may be ameliorated by greater senior input in these cases.
