title: Varus-valgus balance and range of movement after total knee arthroplasty.
abstract: We performed a randomised, prospective study of 80 mobile-bearing total knee arthroplasties (80 knees) in order to measure the effects of varus-valgus laxity and balance on the range of movement (ROM) one year after operation. Forty knees had a posterior-cruciate-ligament (PCL)-retaining prosthesis and the other 40 a PCL-sacrificing prosthesis. In the balanced group (69 knees) in which the difference between varus and valgus was less than 2 degrees, the mean ROM improved significantly from 107.6 degrees to 117.7 degrees (p < 0.0001). By contrast, in the 11 knees which were unbalanced and in which the difference between varus and valgus laxity exceeded 2 degrees, the ROM decreased from a mean of 121.0 degrees to 112.7 degrees (p = 0.0061). We conclude that coronal laxity, especially balanced laxity, is important for achieving an improved ROM in mobile-bearing total knee arthroplasty.
authors.affiliation: Ishii Orthopaedic and Rehabilitation Clinic, 1089 Shimo-Oshi, Gyoda, Saitama 361-0037, Japan. ymatsuda802@nifty.com
authors.forename: Y
authors.initials: Y
authors.lastname: Matsuda
authors.forename: Y
authors.initials: Y
authors.lastname: Ishii
authors.forename: H
authors.initials: H
authors.lastname: Noguchi
authors.forename: R
authors.initials: R
authors.lastname: Ishii
mesh_terms: D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D001696:Biomechanical Phenomena; D005260:Female; D006801:Humans; D007593:Joint Instability / Q000000981:diagnostic imaging / Q000503:physiopathology; D007719:Knee Joint / Q000503:physiopathology*; D007720:Knee Prosthesis; D008297:Male; D016119:Posterior Cruciate Ligament / Q000601:surgery; D011446:Prospective Studies; D011859:Radiography; D016059:Range of Motion, Articular