Article
Prospective midterm results with focus on radiographic aspects of a new anatomical adapted cementless stem-system in total hip arthroplasty.
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Published: | June 13, 2005 |
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Philosophy and aim of the cementless OptanTM-stem is a proximal fixation and force transmission in the femoral bone. A new innovative anatomical adapted design (helitorsion) has been developed therefore. This prospecitve follow-up study (FU) shall confirm this philosophy.
In 1999-2001 175 stems (168 patients: ø 53.1years, female: 52% / male: 48%) were implanted due to primary hip arthritis. Beside clinical parameters (HHS, WOMAC etc.) the FU is focused on the radiographic picture (periprosthetic bone morphology, digital stem position and migration analysis).
Complications: 2 deep infections, 1 aseptic/ 1 septic loosening, 2 revisions after periprosthetic fracture. Survival analysis (Kaplan-Meier) after 4-5 years FU is 0.988. Less than 12% of neutral positioned stems indicate periprosthetic appositional bone reactions (endostal/cortical hypertrophy) in gruen-zones 3-5 and 10-12. Radiolucent lines and osteolyses were not noticed, till now. Reactive endosteal bone lines are visible in distal parts in 12% of cases. No tendency for migration of the stem is measurable (95%-interval is within the accuracy limit of 2mm of the measuring method). In the clinical picture the HHS (WOMAC) changes from 49 up to 98 pts. (7.4 to 9.1 pts.) after THA implantation.
The previous indiviual analysis of the radiograhic follow up shows only poor adaptive changes of the periprosthetic bone. These visible adaptive reactions occur mostly, when the stem position in the femur is not neutral. Regarding this and the clinical results, the philosophy of the uncemented Optan-stem seems to be confirmed, till now.