Moderate varus/valgus malalignment after total knee arthroplasty has little effect on knee function or muscle strength 91 patients assessed after 1 year

Research output: Contribution to journalArticle

Abstract

Background and purpose - Postoperative muscle strength and component alignment are important factors affecting functional results after total knee arthroplasty (TKA). We are not aware of any studies that have investigated the relationship between them. We therefore investigated whether coronal malalignment of the mechanical axis and/or of individual implant components would affect knee muscle strength and function 1 year after TKA surgery. Patients and methods - We included 120 consecutive osteoarthritis (OA) patients admitted for TKA. Preoperative active range of motion (ROM) of the knee, patient age, sex, and BMI were recorded and the Knee Society score (KSS) and knee joint extensor/flexor muscle strength were assessed. At 1-year follow-up, the mechanical and coronal component alignment was measured from a postoperative long standing radiograph, and ROM, KSS, and muscle strength measurements were taken in 91 patients. Functional outcome and muscle strength measurements were compared between normally aligned and malaligned TKA groups. Results - 29 of 91 TKAs were malaligned, i.e. they deviated more than 3 degrees from the neutral mechanical axis. 18 femoral components and 15 tibial components were malaligned. Before surgery, the malaligned and normally aligned groups were similar regarding sex distribution, BMI, ROM, KSS, and muscle strength. At the 1-year follow-up, the differences between the groups regarding knee joint function and muscle strength were small, not statistically significant, and barely clinically relevant. Interpretation - Moderate varus/valgus malalignment of the mechanical axis or of individual components has no relevant clinical effect on function or muscle strength 1 year after TKA surgery.

Details

Authors
  • Justinas Stucinskas
  • Otto Robertsson
  • Aurimas Sirka
  • Aleksej Lebedev
  • Hans Wingstrand
  • Sarunas Tarasevicius
Organisations
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Orthopedics
Original languageEnglish
Pages (from-to)728-733
JournalActa Orthopaedica
Volume86
Issue number6
Publication statusPublished - 2015
Publication categoryResearch
Peer-reviewedYes