Abstract
Cementless distally locked stems were introduced in revision hip arthroplasty (RTHA) in the late 1980s to deal with severe femoral bone loss. These implants have not been assessed over the long-term, particularly the influence of the design and porous coating. Therefore we performed a retrospective case-control study at a minimum 10-years' follow-up comparing the straight Ultime™ stem with 1/3 porous coating versus the anatomical Linea™ stem with 2/3 proximal coating with hydroxyapatite.
We performed a single-center case-control study measuring survival, function based the Harris and Oxford-12 scores, and rate of thigh pain. X-rays were done at regular intervals and at follow-up. No femoral bone graft was used at insertion.
The two groups were comparable in terms of age, sex and follow-up (mean 12.2 years in Ultime and 10.8 years in Linea cohorts); however they differed in the severity of bone loss therefore the results were adjusted according to this variable. Ten-year survival considering revision for any reason was 63.5% ± 5.4 for Ultime and 91.6% ± 2.7 for Linea (p < 0.001). Merle d'Aubigné scores and Oxford-12 were higher in the Linea group 82.9 ± 12.4 and 26.3/48, respectively, versus 69.5 ± 16 and 21/48 in the Ultime group (p < 0.001). Thigh pain was observed in 30% of Ultime cases versus 3% of Linea cases. Bone reconstruction measured via cortical thickness was better in the Linea group and correlated to metaphyseal filling at insertion.
This study confirms the benefits of using of locked stems in RTHA with severe bone loss. Better metaphyseal filling and optimized porous coating help to minimize thigh pain and the revision rate.
