Associations of varus thrust and alignment with pain in knee osteoarthritis.
OBJECTIVE
To investigate associations of varus thrust and varus static alignment with pain in patients with knee osteoarthritis (OA).


METHODS
This was a cross-sectional study of participants from a randomized controlled trial of vitamin D treatment for knee OA. Participants were video recorded while walking and scored for presence of varus thrust. Static alignment was measured on standard posteroanterior knee radiographs. Pain questions from the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire were used to assess symptoms. We calculated means for total WOMAC pain in relation to varus thrust and static varus alignment (i.e., corrected anatomic alignment<178 degrees). Ordinal logistic regressions were performed, with responses on individual WOMAC pain questions as the outcomes and varus thrust and varus alignment as the predictors.


RESULTS
There were 82 participants, 60% of whom were female. The mean±SD age was 65.1±8.5 years, and the mean±SD body mass index was 30.2±5.4 kg/m2. The mean total WOMAC pain score was 6.3 versus 3.9, respectively, in those with versus without definite varus thrust (P=0.007) and 5.0 versus 4.2 in those with versus without varus alignment (P=0.36). Odds ratios for pain with walking and standing were 4.7 (95% confidence interval 1.8-11.9) and 5.5 (95% confidence interval 2.2-14.2), respectively, in those with and those without definite varus thrust. There were no significant associations between varus alignment and responses to individual WOMAC pain questions. Sensitivity analyses suggested that varus classified using a more stringent definition might have been associated with pain on walking and standing.


CONCLUSIONS
In patients with knee OA, varus thrust, and possibly varus static alignment, were associated with pain, specifically during weight-bearing activities. Treatment of varus thrust (e.g., via bracing or gait modification) may lead to improvement of symptoms.
Michael E. DeBakey VA Medical Center, Houston VA Health Services Research and Development Center of Excellence, and Baylor College of Medicine, Houston, Texas 77030, USA. ghlo@bcm.edu
Grace H
GH
Lo
William F
WF
Harvey
Timothy E
TE
McAlindon
D000328:Adult; D000368:Aged; D001696:Biomechanical Phenomena; D017760:Bone Malalignment / Q000150:complications* / Q000000981:diagnostic imaging; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D007717:Knee / Q000000981:diagnostic imaging*; D007719:Knee Joint / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D020370:Osteoarthritis, Knee / Q000150:complications* / Q000000981:diagnostic imaging; D010146:Pain / Q000150:complications* / Q000000981:diagnostic imaging; D010147:Pain Measurement; D011859:Radiography; D016032:Randomized Controlled Trials as Topic; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D016138:Walking; D016474:Weight-Bearing