title: Joint area constraint had no influence on bone loss in proximal tibia 5 years after total knee replacement.
abstract: After total knee replacement (TKR) the bone mineral density (BMD) decreases in the proximal tibia. Our aim was to evaluate if changes in constraint of the cemented AMK TKR (DePuy, Johnson & Johnson, Leeds, UK) had any effect on postoperative bone remodeling in the proximal tibia. We used dual-energy X-ray absorptiometry in 43-53 knees to record changes in BMD in three regions of interest around the tibial component up to 5 years after operation with the AMK (DePuy) TKR. The knees had been randomly allocated to receive a flat or a concave tibial insert with retention of the posterior cruciate ligament when preoperative deformity was less severe, and either a concave or a posterior-stabilized (PS) insert with resection of the posterior cruciate ligament when deformity was more pronounced. All designs were associated with loss of BMD in the proximal tibia. The mean bone loss varied from 5 to 23% depending on the region of interest. There were no statistically significant differences between the groups, and the alteration of tibial insert constraint did not influence the bone remodeling. However, low precision values may have impaired the detection of differences.
authors.affiliation: Department of Orthopaedics, Sahlgrenska University Hospital, Göteborg University, S-413 45 Göteborg, Sweden. tuuli.saari@vgregion.se
authors.forename: Tuuli
authors.initials: T
authors.lastname: Saari
authors.forename: Johan
authors.initials: J
authors.lastname: Uvehammer
authors.forename: Lons
authors.initials: L
authors.lastname: Carlsson
authors.forename: Lons
authors.initials: L
authors.lastname: Regnér
authors.forename: Johan
authors.initials: J
authors.lastname: Kärrholm
mesh_terms: D015502:Absorptiometry, Photon; D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D015519:Bone Density; D016723:Bone Remodeling; D001862:Bone Resorption / Q000000981:diagnostic imaging / Q000209:etiology* / Q000473:pathology; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009068:Movement; D016119:Posterior Cruciate Ligament / Q000601:surgery; D011183:Postoperative Complications / Q000000981:diagnostic imaging / Q000209:etiology / Q000473:pathology; D011474:Prosthesis Design; D013977:Tibia / Q000000981:diagnostic imaging / Q000473:pathology*