FIXATION MODE OF AN INTRA-OPERATIVE MANUFACTURED CUSTOM MADE PROSTHESIS STEM INFLUENCES OUTCOME OF TOTAL HIP REPLACEMENT

Abstract

Success of a total hip replacement is commonly assessed by the Haris Hip Score (HHS), which provides information on pain reduction and regained mobility. Radiographic images provide information relative to the stability of the prosthesis.

We use the intraoperatively manufactured prosthesis since 1989; the initially performed THR were done with uncoated prostheses. After introduction of the hydroxyapatite coating our prosthesis stems were coated.

We retrospectively evaluated the clinical and radiographic outcome of 3 patient cohorts who received intra-operatively custom made stem prosthesis.

• Group 1: Uncoated stem prosthesis fixated with tro-chanteric osteotomy.

• Group 2: Uncoated stem cementless implant

• Group 3: Cementless hydroxyapatite coated stem prosthesis

Clinical assessment and radiographic assessment is performed using pre-operatively and at each follow-up visit.

Baseline data are the pre-operative HHS and first radiography postoperatively. These data are compared with the data of the latest follow-up visit.

RX’s are scored according to the ARA score.

Records were analysed for 83 patients in group 1, with a mean follow-up period of 93 months. In group 2, 35 patients were followed for 105 months and 54 patients from group 3 were followed for 41 months.

In the 3 groups the HHS at follow-up was > 75, this means an improvement of minimum 25 points for group 1 and 2 (baseline HHS for group 2 was not available)

The mean ARA scores at follow-up were 1.6; 1.7 and 5.3 for respectively group 1; 2 and 3.

Clinical outcome is comparable in the three studied cohorts.

The ARA score is indicating poor outcome for the uncoated prosthesis, regardless of the type of fixation, while the coated prosthesis group has a good to excellent ARA score.

These findings tend to confirm the superiority of the hydroxyapatite coated prosthesis.