AVASCULAR NECROSIS AFTER INTERNAL FIXATION OF INTRACAPSULAR HIP FRACTURES; A STUDY OF THE OUTCOME FOR 1023 PATIENTS

Abstract

There is continuing debate regarding the merits of internal fixation versus arthroplasty for intracapsular hip fractures. For displaced fractures there is a higher risk of fracture healing complications but many of the studies reporting on this are now from some years ago using surgical methods that are now outdated. The aim of our study was to determine the incidence of avascular necrosis (AVN) related to age, gender, displacement and operation delay for a large series of patients with intra-capsular fractures treated with internal fixation using contemporary methods.

We prospectively studied 1023 patients, 988 fractures were internally fixed with three cannulated screws and 35 with a sliding hip screw. The average length of radiographic follow-up for those patients who survived to one year was 337 days (range 25 to 3521 days). The average age of the patients was 75.4 years (range 16–100); 243 (23.8%) were male. The overall incidence of AVN was 6.6%. AVN was less common (p=0.0004) for undisplaced fractures than for displaced fractures (21 of 528 [4.0%] vs 47 of 495 [9.5%]) and in men than women (p=0.03) who had a displaced fracture (7 of 143 [4.9%] vs 40 of 352 [11.4%]). The incidence of AVN for those aged less than 60 years and who sustained a displaced fracture was 20.6%, compared to 12.5% for those aged 60–80 years and 2.5% for those aged more than 80 years (p< 0.0001). We found no association between the incidence of AVN and operation delay.

Our study showed an increased risk of AVN with younger age and in females with a displaced fracture. This is in contrast to the decreased incidence of non-union seen with younger age. Knowledge of the predicted incidence of fracture healing complications should help surgeons make a more balanced decision between internal fixation and arthroplasty for this condition.