Abstract
Hypothesis
The Synergy femoral component was introduced in 1996 as a second generation titanium proximally porous-coated tapered stem with dual offsets to help better restore femoral offset at THR. The purpose of this prospective study was to evaluate the long-term (minimum 10 year) clinical and radiographic results and survivorship of this femoral component at our institution.
Methods & Analysis
From 1996 to 1999, 256 cementless Synergy femoral components were inserted and followed prospectively in 254 patients requiring THR. 185 were standard offset stems (72.3%) while 71 stems (27.7%) were high offset. The average follow-up was 11.2 years (range 10.0 to 12.9 years). Average age at index THR was 58.9 year. Two hundred and eight stems had standard porous coating while 48 had additional HA coating. Fifty-two cases were either lost to follow-up or had died prior to 10 years follow-up. Patients were followed prospectively using validated clinical outcome scores and radiographs. Kaplan-Meier survival analysis was performed.
Results
All health-related outcomes were significantly improved from pre-operative with a mean Harris Hip score and WOMAC at last follow-up of 91.6 and 81.8, respectively. From the initial 256 femoral stems inserted, only 5 stems have been revised. Two stems have been revised for infection. Only one stem has been revised due to subsidence at nine months, likely as a result of a calcar fracture at the index THR. Two stems were revised for peri-prosthetic fracture as a result of patient falls. Radiographic review of remaining stems in situ identified no cases of loosening. Kaplan-Meier survivorship analysis of the femoral component, with revision for aseptic loosening, was 99.2% at 12 years.
Conclusion
The Synergy femoral component, a second generation titanium proximally porous-coated tapered stem design with dual offsets, has demonstrated excellent clinical and radiographic results and long-term survivorship (99% at 10 years) at our institution.
