title: A randomised controlled trial of kinematically and mechanically aligned total knee replacements: two-year clinical results.
abstract: We have previously reported the short-term radiological results of a randomised controlled trial comparing kinematically aligned total knee replacement (TKR) and mechanically aligned TKR, along with early pain and function scores. In this study we report the two-year clinical results from this trial. A total of 88 patients (88 knees) were randomly allocated to undergo either kinematically aligned TKR using patient-specific guides, or mechanically aligned TKR using conventional instruments. They were analysed on an intention-to-treat basis. The patients and the clinical evaluator were blinded to the method of alignment. At a minimum of two years, all outcomes were better for the kinematically aligned group, as determined by the mean Oxford knee score (40 (15 to 48) versus 33 (13 to 48); p = 0.005), the mean Western Ontario McMaster Universities Arthritis index (WOMAC) (15 (0 to 63) versus 26 (0 to 73); p = 0.005), mean combined Knee Society score (160 (93 to 200) versus 137 (64 to 200); p= 0.005) and mean flexion of 121° (100 to 150) versus 113° (80 to 130) (p = 0.002). The odds ratio of having a pain-free knee at two years with the kinematically aligned technique (Oxford and WOMAC pain scores) was 3.2 (p = 0.020) and 4.9 (p = 0.001), respectively, compared with the mechanically aligned technique. Patients in the kinematically aligned group walked a mean of 50 feet further in hospital prior to discharge compared with the mechanically aligned group (p = 0.044). In this study, the use of a kinematic alignment technique performed with patient-specific guides provided better pain relief and restored better function and range of movement than the mechanical alignment technique performed with conventional instruments.
authors.affiliation: Phoenix Veterans Affairs Health Care System, P.O. Box 27410, Scottsdale, Arizona, 85255, USA.
authors.forename: H G
authors.initials: HG
authors.lastname: Dossett
authors.affiliation: Veterans Affairs Salt Lake City Health Care System, 500 Foothill, Drive, Salt Lake City, Utah 84104, USA.
authors.forename: N A
authors.initials: NA
authors.lastname: Estrada
authors.affiliation: Phoenix Veterans Affairs Health Care System, 650 E. Indian School Road Phoenix Arizona, 85012, USA.
authors.forename: G J
authors.initials: GJ
authors.lastname: Swartz
authors.affiliation: Phoenix Veterans Affairs Health Care System, 650 E. Indian School Road Phoenix Arizona 85012, USA.
authors.forename: G W
authors.initials: GW
authors.lastname: LeFevre
authors.affiliation: Phoenix Veterans Affairs Health Care System, 650 E. Indian School Road Phoenix Arizona 85012, USA.
authors.forename: B G
authors.initials: BG
authors.lastname: Kwasman
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D019645:Arthroplasty, Replacement, Knee / Q000295:instrumentation* / Q000379:methods; D001696:Biomechanical Phenomena; D017760:Bone Malalignment / Q000517:prevention & control; D005260:Female; D006801:Humans; D057194:Intention to Treat Analysis; D007719:Knee Joint / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000601:surgery; D016059:Range of Motion, Articular; D020127:Recovery of Function; D016896:Treatment Outcome
keywords: Kinematic alignment; Kinematic alignment total knee replacement; Knee arthroplasty; Knee replacement; TKA; Total knee arthroplasty alignment; Total knee replacement; Total knee replacement alignment