Aims

The highly cross-linked polyethylene Exeter RimFit flanged cemented acetabular component was introduced in the United Kingdom in 2010. This study aimed to examine the rates of emergence of radiolucent lines observed when the Rimfit acetabular component was implanted at total hip arthroplasty (THA) using two different techniques: firstly, the ‘rimcutter’ technique in which the flange sits on a pre-prepared acetabular rim; and secondly, the ‘trimmed flange’ technique in which the flange is trimmed and the acetabular component is seated inside the rim of the acetabulum.

The aim of this study was to establish any association between implant cut-out and a Tip Apex Distance (TAD), ≥25mm, in proximal femoral fractures, following closed reduction and stabilisation, with either a Dynamic Hip Screw (DHS) or Intramedullary Hip Screw (IMHS) device. Furthermore, we investigated whether any difference in cut-out rate was related to fracture configuration or implant type.

WE conducted a retrospective review of the full clinical records and radiographs of 65 consecutive patients, who underwent either DHS or IMHS fixation of proximal femoral fractures. The TAD was measured in the standard fashion using the combined measured AP and lateral radiograph distances. Fractures were classified according to the Muller AO classification.

35 patients underwent DHS fixation and 30 patients had IMHS fixation. 5 in each group had a TAD≥25mm. There were no cut-outs in the DHS group and 3 in the IMHS group. 2 of the cut-outs had a TAD≥25mm. The 3 cut-outs in the IMHS group had a fracture classification of 31-A2, 31-A3 and 32-A3.1 respectively. In addition, the fractures were inadequately reduced and fixed into a varus position.

A TAD<25mm would appear to be associated with a lower rate of cut-out. The cut-out rate in the IMHS group was higher than the DHS group. Contributing factors may have included an unstable fracture configuration and inadequate closed fracture reduction at the time of surgery.