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Mobile-bearing TKR prosthesis shows good 15-year results
At final follow-up, no components had changed position and only three cases developed periprosthetic osteolysis.
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Fifteen-year follow-up data show total knee replacement performed using a cemented rotating platform mobile-bearing prosthesis provides good functional results over the long-term, according to a study presented at the American Academy of Orthopaedic Surgeons meeting.
“At 15-year radiographic follow-up there was no evidence of loosening and only three patients had periprosthetic osteolysis,” said Michael R. O’Rourke, MD, one of the authors of the study. “There were three reoperations — one for infection and two for traumatic supracondylar periprosthetic fractures — but no knees were revised for loosening, osteolysis or wear.”
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COURTESY: MICHAEL R. O’ROURKE | |
O’Rourke and colleagues at the University of Iowa Hospital and Clinics, Iowa City, evaluated the long-term durability of TKR performed using the LCS Complete (DePuy). The study initially included 119 knees among 86 patients with an average age of 70 years. Diagnoses included osteoarthritis in 105 knees (88%), rheumatoid arthritis in 12 knees (10%), and post-traumatic arthritis in two knees (2%). The same surgeon performed all procedures between November 1985 and November 1988, O’Rourke said.
Although no patients had been lost to follow-up, the 15-year results included 53 knees among 37 patients; one patient had refused to participate and the remaining patients had died. However, the authors contacted the next of kin for all deceased patients to determine whether the patients had undergone surgical revision prior to death.
At final follow-up, the mean Hospital for Special Surgery (HSS) score improved from 61 at preop to 79 among the 37 remaining patients. The mean Knee Society (KS) clinical score improved from 43 at preop to 85 at postop, and the mean KS functional score improved from 49 to 58, according to the study.
Mean range of motion decreased slightly among the remaining patients, from 114° at preop to 105° at final follow-up. No patients had undergone revision of any patellar, tibial or femoral components, but two patients required reoperation for periprosthetic fractures and one patient required reoperation for hematogeneous infection, O’Rourke said.
Radiographic follow-up averaged eight years overall and 14 years among the remaining living patients, 74% of whom had a minimum of 15 years radiographic follow-up.
Overall, the authors noted incomplete radiolucencies in the femoral components of 28 knees (24%), in the tibial components of 27 knees (23%), and in the patellar components of eight knees (7%).
Among the 37 remaining living patients, 16 knees (30%) had incomplete femoral radiolucencies, 13 knees (25%) had incomplete tibial radiolucencies, and seven knees (13%) had incomplete patellar radiolucencies.
Only one patient developed radiolucencies in three KS zones, O’Rourke said, noting no tibial or patellar radiolucencies developed in more than two zones and no cases had radiolucencies greater than 2 mm.
No components changed position during follow-up and none developed component subsidence or loosening.
For more information:
- Iossi MF, Callaghan JJ, O’Rourke MR, et. al. Cemented rotating platform total knee replacement: A minimum fifteen-year follow-up study. #366. Presented at the American Academy of Orthopaedic Surgeons 72nd Annual Meeting. Feb. 23-27, 2005. Washington.