Abstract
The purpose of this study was to assess the clinical and radiological outcome following spring plate fixation of posterior wall fractures.
Spring plates are fashioned from a one third tubular plate cutting through one of the holes in the plate and bending the sharp edges through 90 degrees allowing screw fixation of small acetabular margin fragments well away from the joint reducing the risk of joint penetration.
From July 1993 to August 2004, 89 patients with displaced posterior wall fractures underwent posterior wall fixation with one or more spring plates. Patients were assessed post-operatively with a CT scan and annually for up to 5 years for a clinical and radiological assessment. Clinically patients were graded according to the Epstein modification of Merle d'Aubigné/Postel Hip Score. The radiographs were graded using the Roentographic Grade criteria used by Matta.
Patients were reviewed at a mean 55 month follow-up. There were 12 post-operative complications. Clinically excellent or good results were seen in 70% and radiologically in 70%. There were 15 revisions for osteonecrosis, infection and osteoarthritis. 91% (20/22) of fractures had excellent/good clinical results if reduced anatomically compared with 66% (24/36) of those reduced to within 2mm as assessed by the post-operative CT scan. Only 44% (8/18) of those reduced leaving a gap of greater than 2mm had an excellent/good clinical result.
Posterior wall fractures can be treated successfully by the use of spring plates. Clinical results correspond closely with radiological appearance. The accuracy of reduction correlates highly with the subsequent prognosis and we recommend routine post-operative CT scanning to identify misplaced metalwork and the accuracy of reduction to help predict prognosis.
