MIGRATION RATES OF THE COLLARLESS POLISHED TAPERED (CPT) HIP REPLACEMENT

Abstract

Introduction: The aims of this study are:

To report and validate the early migration rates of the collarless polished tapered hip replacement using manual and computer measurements

To report early clinical results of the CPT hip

Patients and methods: 80 patients undergoing primary total hip replacement in a single centre were prospectively recruited into the trial. There were 59 females and 21 males: age range 31–84 years, (mean 68 years sd 9.86). Surgery was performed through an anterolateral approach in all cases. A standard cementing technique using a cement gun and cement restrictor was employed. The patients had standardised anteroposterior standing hip radiographs taken post operatively, then yearly. The migration was measured along the long axis of the femoral component In the anteroposterior plane, using the tip of the greater trochanter as a bony landmark. Measurements were made by two independent observers (specialist registrars). Plain radiographs were measured manually using a ruler and set square and digitised images using a software package designed in-house at Dundee University. Correction for magnification was incorporated. Hip assessments were performed at each review by an independent reviewer.

Results: The mean migration rates and 95% confidence intervals (Cl) and mean Harris pain and Harris hip scores and Std Deviations were:

There was no significant difference between inter or intra observer measurements for hip migration.

This is the first study to date that we are aware of that describes the subsidence rates of the CPT hip which includes validation by inter and intra observer readings.