Integrity of posterior retinaculum after displaced femoral neck fractures.

INTRODUCTION

It is widely thought that the posterior retinaculum is intact only in relatively undisplaced intracapsular fractures, and interruption of the arterial flow through the retinacular arteries to the femoral head is the main cause of avascular necrosis after fracture of the neck.

PATIENTS

In order to test the hypothesis that the posterior retinaculum is torn after a displaced femoral neck fracture, 112 patients (45 males and 67 females), 75 years old on average, underwent a hemiarthroplasty for a displaced femoral neck fracture. There were 71 Garden type III and 41 Garden type IV fractures. The integrity of the posterior retinaculum was examined intraoperatively in every patient during the procedure.

RESULTS

The posterior retinaculum was found intact in all of the Garden type III fractures and in 39 Garden type IV fractures. The posterior retinaculum was found torn in two Garden type IV fractures. There was no tearing in any other part of the capsule of the hip joint in any patient.

CONCLUSIONS

The posterior retinaculum of the hip joint remains intact after a displaced femoral neck fracture in all of Garden type III fractures and in the great majority of Garden type IV fractures.