Comparison of wear rate and osteolysis between annealed and remelted highly cross-linked polyethylene in total hip arthroplasty. A case control study at 7 to 10 years follow-up.
Low polyethylene wear rate and low incidence of osteolysis after total hip arthroplasty using annealed and remelted highly cross-linked polyethylene have been reported. However, there is no previous report that directly compared both types of highly cross-linked polyethylene. We therefore performed a retrospective study on a series of highly cross-linked polyethylene, in order to: (1) compare wear rates and the incidence of osteolysis between annealed and remelted highly cross-linked polyethylene at 7-10 years; (2) identify the frequency of complication related to annealed and remelted highly cross-linked polyethylene.



There is no difference in the linear wear rate and the incidence of osteolysis between the annealed and remelted highly cross-linked polyethylene in total hip arthroplasty.



Two hundred and sixteen cases of cementless total hip arthroplasties with annealed or remelted highly cross-linked polyethylene, which were performed between January 2003 and December 2006 in one institution, were followed for 7-10 years and received computed tomography scan, in addition to radiography at the latest follow-up. Annealed and remelted highly cross-linked polyethylene was used in 91 cases and 125 cases, respectively. A 26-mm cobalt-chromium head was used in all cases. Penetration rates from 1 year to the last evaluation were used to estimate the yearly linear wear rate. Existence of osteolysis was evaluated by plain radiography and computed tomography.



There were no significant differences in patients' background between the two groups. The linear wear rate of annealed and remelted group was 0.031±0.022mm/year and 0.032±0.020mm/year, respectively (P=0.91). Two cases of small femoral osteolysis were found in the annealed group. Any complication related to highly cross-linked polyethylene was not found in both groups.



There was no significant difference in the linear wear rate and the incidence of osteolysis between the annealed and remelted group at postoperative 7 to 10 years. Excellent results of both types of highly cross-linked polyethylene were revealed by this study.



Level III retrospective case control study.
Department of Orthopaedic Surgery, Medical Hospital, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519 Tokyo, Japan.
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R
Takada
Department of Orthopaedic Surgery, Medical Hospital, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519 Tokyo, Japan. Electronic address: jinno.orth@tmd.ac.jp.
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T
Jinno
Department of Orthopaedic Surgery, Medical Hospital, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519 Tokyo, Japan.
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D
Koga
Department of Orthopaedic Surgery, Medical Hospital, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519 Tokyo, Japan.
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M
Hirao
Department of Orthopaedic Surgery, Medical Hospital, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519 Tokyo, Japan.
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T
Muneta
Department of Orthopaedic Surgery, Medical Hospital, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo-ku, 113-8519 Tokyo, Japan.
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A
Okawa
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019644:Arthroplasty, Replacement, Hip / Q000295:instrumentation*; D016022:Case-Control Studies; D005260:Female; D005269:Femur / Q000000981:diagnostic imaging; D005500:Follow-Up Studies; D006622:Hip Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010014:Osteolysis / Q000000981:diagnostic imaging / Q000209:etiology*; D020959:Polyethylene / Q000009:adverse effects; D011475:Prosthesis Failure; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed
D020959:Polyethylene
Bearings; Cementless; Computed tomography; First-generation highly cross-linked polyethylene; Fit and fill stem