Abstract
Introduction: Revision surgery for stem loosening and peri-implant bone loss of variable extent is a major challenge for orthopedic surgeons. Our strategy has been to use cementless straight stems of rectangular cross-section for revisions. To ascertain the value of this implant we analyzed the results at a minimum follow-up of 10 years.
Material and Method: Between October 1991 and end 1998, 125 patients (134 hips) underwent revision surgery. Of these, 39 were males and 86 were females. Sixty-seven of the original implants were cemented and as many were cementless. Cementless revision stems (SLR; Plus Orthopedics, Aarau, Switzerland) size 3 to 11 (180 to 223 mm in length) were used for revisions. Patient age at the time of surgery was 37.8 to 89.3 (mean, 71.0) years.
Fifty patients (53 hips) died post revision 0.0 to 13.5 (mean, 6.8) years. Their implants had been followed-up radiographically for 0.0 to 9.2 (mean, 3.6) years. At the time of revision these patients had been 48.9 to 89.3 (mean, 76.7) years old. One of them had undergone stem revision for aseptic loosening one year post surgery. Another 6 were revised 1.4 to 13.9 years post surgery, 5 for low grade infection and 1 for peri-implant fracture.
Seven patients refused to present for follow-up because of advanced age and poor cooperation. Eight were contacted by telephone. These 15 patients were not re-operated. Five patients were altogether lost to follow-up, thus leaving a total of 53 hips (49 patients) for analysis at a follow-up time of at least 10 years. The follow-up time was 10.0 to 16.1 (mean, 11.6) years.
For radiographic follow-ups monitor-guided a.-p. and axial radiographs were recorded. These were analyzed by Gruen zones.
Results: All stems were properly aligned along the long femoral axis, except in 1 patient, who had sustained a peri-implant fracture during a fall with axial stem subsidence responding to conservative treatment. In 38 patients peri-implant bone apposition was detected in all 7 Gruen zones. This was combined with bone resorption in other zones in 2 patients. Four patients presented with osteolytic lesions. In one of them with metal-on-metal articulating surfaces, the lesion extended to several segments and will necessitate revision. All other stems were stable. None of them was at risk.
Conclusion: This analysis showed that the SLR revision stem performs well for an intermediate follow-up time of at least 10 years.
Correspondence should be addressed to: EFORT Central Office, Technoparkstrasse 1, CH – 8005 Zürich, Switzerland. Email: office@efort.org
