title: Press-fit versus cemented all-polyethylene patellar component: midterm results.
abstract: This study compared the midterm results between press-fit and cemented implantation of a highly congruent, all-polyethylene patellar component. We followed prospectively 172 implants (cemented, n = 133; press-fit, n = 39). Average follow up was 6 years (range, 5-8 years). Patellofemoral complications occurred in 4 cemented patellae (2.3%). Two of these patellae required revision. Cemented implants had a significantly higher incidence of patellar maltracking (30% vs 8%; P= .005). No significant differences in the overall Knee Society scores (mean, 165; SD, 27) or any of its components relevant to patellofemoral function were detected between fixation methods. A retrieved specimen showed an intervening fibrous membrane at the implant-bone interface. The potential for macrophage-mediated osteolysis at this site is unknown. No other adverse outcome was associated with press-fit implantation. These results suggest that at midterm follow-up, press-fit implantation of this all-polyethylene patellar component may improve tracking and represents a viable alternative to cement fixation.
authors.affiliation: Division of Orthopaedic Surgery, London Health Sciences Center, University of Western Ontario, London, Ontario, Canada.
authors.forename: Gonzalo G
authors.initials: GG
authors.lastname: Valdivia
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Dunbar
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Jenkinson
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Macdonald
authors.forename: Cecil H
authors.initials: CH
authors.lastname: Rorabeck
authors.forename: Robert B
authors.initials: RB
authors.lastname: Bourne
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000379:methods*; D001843:Bone Cements; D004867:Equipment Design; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007720:Knee Prosthesis; D008297:Male; D008875:Middle Aged; D011095:Polyethylenes; D011183:Postoperative Complications / Q000209:etiology; D011446:Prospective Studies; D016896:Treatment Outcome
chemical_list: D001843:Bone Cements; D011095:Polyethylenes