Abstract
Background: Total Hip Replacements in younger active patients continues to pose a major challenge. Surface replacement techniques, designed to preserve bone stock do not yet have proven long term results. Early cemented designs in this population had high failure rates. Concept of fixation of total hip prosthesis by bony in-growth rather than by cement is an attempt to decrease the incidence of loosening. Ceramic joint surfaces produce minimal wear debris.
Objectives: A medium term follow-up of clinical and radiological results of the JRI Furlong hydroxyapatite coated prosthesis with ceramic bearing surfaces in young active patients.
Methods: A retrospective analysis of 43 JRI Furlong Hip Replacements (mean age 32 Yrs) in 33 patients is presented. The minimum follow-up was 60 months. Functional assessment was done using the Harris Hip Score. Radiolucency around the femoral stem according to Gruen (zone 1-7) and the acetabulum as described by Charnly and De Lee (zone 1–3) is documented. A fully coated femoral component along with the press –fit HA coated CSF cup with a 28mm ceramic insert was used. All cups were routinely augmented with screws.
Results: The mean Harris Hip score was 90 (46–96). 4 patients had a score less than 80. 84.2% were completely pain free. Acetabular radioleucencies were noted in 32 hips (72 %).28 cups had radiolucent lines (RLL) in zone 2, 2 cups in zone 1 and 1 cup in zone 3. In 10 patients (23%) the lucent area measured > 2mm at the cup bone interface. No hips had RLL in more than two zones. 4 stems had RLL > 2 mm involving the Gruen zone 7. 90 % showed a distinct osteoblastic reaction at the tip of the femoral component. There was no calcar resorption, endosteal cavitation or ectopic ossification. There were no instances of ceramic fractures and no hips were revised.
Discussion: The JRI Furlong hip gives good functional results in young patients in the medium term. Although of concern, there was no co-relation between the presence of acetabular RLL and functional outcome. The RLLs were not thought to be progressive. The RLLs can be explained by backside wear or by fretting of the screws by the ceramic liner. Long term follow up of the CSF cup will be required to determine if these radio-lucent lines are an early sign of failure at the interface or whether they simply represent stable in- growth of fibrous tissue in this highly stressed region.
Theses abstracts were prepared by Professor Roger Lemaire. Correspondence should be addressed to EFORT Central Office, Freihofstrasse 22, CH-8700 Küsnacht, Switzerland.
