title: Coronal laxity in extension in vivo after total knee arthroplasty.
abstract: We performed stress arthrometric studies on 77 knees (71 patients) with total knee arthroplasty to determine the presence and magnitude of femoral abduction and adduction in knee extension. A total of 53 knees (49 patients) had posterior cruciate ligament-retaining (PCLR) prostheses, and 24 (22 patients) had PCL-substituting (PCLS) prostheses. The selected patients had successful arthroplasties with no clinical complications a minimum of 5 years after primary surgery. Each patient was subjected to a successive abduction and adduction stress test at 0 degrees -20 degrees of flexion using a Telos arthrometer. The mean values for abduction and adduction were 4.8 degrees and 4.5 degrees with a PCLR prosthesis, respectively, and 4.6 degrees and 4.0 degrees with a PCLS prosthesis. There were no statistical differences between PCLR and PCLS knees. The results suggest that approximately 4 degrees of laxity in these directions is suitable in total knee arthroplasty for a satisfactory clinical outcome 5-9 years after surgery.
authors.affiliation: Ishii Orthopaedic and Rehabilitation Clinic, 1089 Shimo-Oshi, Gyoda, 361-0037, Japan.
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Ishii
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Matsuda
authors.forename: Ryo
authors.initials: R
authors.lastname: Ishii
authors.forename: Shigeo
authors.initials: S
authors.lastname: Sakata
authors.forename: Go
authors.initials: G
authors.lastname: Omori
mesh_terms: D000368:Aged; D001172:Arthritis, Rheumatoid / Q000503:physiopathology / Q000601:surgery; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007593:Joint Instability / Q000209:etiology* / Q000503:physiopathology*; D007719:Knee Joint / Q000503:physiopathology* / Q000601:surgery*; D008297:Male; D020370:Osteoarthritis, Knee / Q000503:physiopathology / Q000601:surgery; D017063:Outcome Assessment, Health Care; D016119:Posterior Cruciate Ligament / Q000503:physiopathology / Q000601:surgery; D016059:Range of Motion, Articular / Q000502:physiology*; D013314:Stress, Mechanical; D013997:Time Factors; D016474:Weight-Bearing / Q000502:physiology