title: The Otto Aufranc Award. Highly cross-linked polyethylene in total hip arthroplasty: randomized evaluation of penetration rate in cemented and uncemented sockets using radiostereometric analysis.
abstract: The annual wear rate in polyethylene articulations should be 0.1 mm or less to avoid future osteolysis. Highly cross-linked polyethylene shows an 80 to 90% wear reduction in hip simulator testing, but the clinical documentation of this new polyethylene is still inadequate. We evaluated the highly cross-linked polyethylene in two prospective randomized clinical studies. Thirty-two patients (12 men, 20 women; 64 hips) with a median age of 48 years (range, 29-70 years) with bilateral primary or secondary arthrosis of the hip had hybrid total hip arthroplasty with liners made of highly cross-linked polyethylene on one side and conventional polyethylene on the other. Twenty-seven patients in this study have passed 2 years followup. A further group, comprised of 60 patients (61 hips) with a median age of 55 years (range, 35-70 years), was randomized to receive either highly cross-linked polyethylene or conventional cemented all-polyethylene of the same design. Forty-nine of these 60 patients have been observed for 3 years. In both studies all patients received Spectron stems with 28-mm Co-Cr heads. Radiostereometric examinations with the patient supine or standing were done at regular intervals. Wear was measured in the supine position from the first postoperative week, whereas standing examinations were initiated 3 months after the operation. The penetration rate almost was identical in the study and control groups at 6 months after the operation. Thereafter, the penetration rate leveled out in the two groups with highly cross-linked polyethylene. At 2 years the highly cross-linked polyethylene liner showed 62% lower proximal penetration and 31% lower total (three-dimensional) penetration when the patients were examined in supine position. The highly crosslinked all-polyethylene cemented cups showed lower proximal penetration in both positions. The better wear performance of highly cross-linked polyethylene could increase the implant longevity. Longer followup is needed to evaluate if this new material is associated with less occurrence of osteolysis.
authors.affiliation: Department of Orthopaedics, Institute of Surgical Science, Sahlgrenska University Hospital, Göteborg University, S-41345, Göteborg, Sweden. georgios.digas@vgregion.se
authors.forename: Georgios
authors.initials: G
authors.lastname: Digas
authors.forename: Johan
authors.initials: J
authors.lastname: Kärrholm
authors.forename: Jonas
authors.initials: J
authors.lastname: Thanner
authors.forename: Henrik
authors.initials: H
authors.lastname: Malchau
authors.forename: Peter
authors.initials: P
authors.lastname: Herberts
mesh_terms: D000328:Adult; D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000379:methods*; D001363:Awards and Prizes; D001843:Bone Cements; D005260:Female; D005500:Follow-Up Studies; D006622:Hip Prosthesis; D006801:Humans; D008297:Male; D008875:Middle Aged; D015207:Osteoarthritis, Hip / Q000000981:diagnostic imaging / Q000601:surgery*; D020959:Polyethylene; D011336:Probability; D011474:Prosthesis Design; D011475:Prosthesis Failure; D011859:Radiography; D016032:Randomized Controlled Trials as Topic; D016059:Range of Motion, Articular / Q000502:physiology; D020127:Recovery of Function; D018570:Risk Assessment; D012720:Severity of Illness Index; D018709:Statistics, Nonparametric; D013548:Sweden; D013997:Time Factors; D016896:Treatment Outcome
chemical_list: D001843:Bone Cements; D020959:Polyethylene