Quantifying varus and valgus thrust in individuals with severe knee osteoarthritis.
Varus-valgus thrust is a biomechanical characteristic linked to knee osteoarthritis disease progression. This study aimed to determine: i) direction of thrust in individuals awaiting total knee arthroplasty versus controls, ii) whether thrust and related parameters differed between groups, iii) differences between osteoarthritis patients awaiting surgery with varus and valgus thrust.



44 patients scheduled for surgery and 40 asymptomatic participants were recruited.



varus-valgus thrust excursion and absolute thrust magnitude, quantified by 3D gait analysis.



Few differences were found between the osteoarthritis group and controls. The osteoarthritis group as a whole had a more varus knee angle during early- (p<0.0001) and mid-stance (p=0.010) versus controls. The varus thrust osteoarthritis subgroup had a more varus knee angle in overall (p=0.012), early- (p<0.001), and mid- (p<0.001) stance, and a higher peak knee adduction moment (p=0.019) and impulse (p=0.001) when compared to varus thrust controls. No differences were found between the valgus thrust osteoarthritis and control groups. The varus thrust osteoarthritis group had a greater varus peak knee angle in overall (p<0.001), early- (p<0.001), and mid- (p<0.001) stance, higher peak knee adduction moment (p<0.001) and impulse (p=0.001), more varus static alignment (p=0.014), and lower quadriceps strength (p=0.035) than the valgus thrust osteoarthritis group.



Those with severe osteoarthritis and a varus thrust have poorer biomechanics, more varus static knee alignment, and lower quadriceps strength compared to those with osteoarthritis with a valgus thrust. Further work is needed to determine if these findings impact total knee arthroplasty outcome.
Centre for Health, Exercise and Sports Medicine, Department of Physiotherapy, School of Health Sciences, The University of Melbourne, Melbourne, VIC, Australia. Electronic address: lsosdian@student.unimelb.edu.au.
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Sosdian
Centre for Health, Exercise and Sports Medicine, Department of Physiotherapy, School of Health Sciences, The University of Melbourne, Melbourne, VIC, Australia.
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Hinman
Centre for Health, Exercise and Sports Medicine, Department of Physiotherapy, School of Health Sciences, The University of Melbourne, Melbourne, VIC, Australia. Electronic address: timw@unimelb.edu.au.
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Wrigley
Centre for Health, Exercise and Sports Medicine, Department of Physiotherapy, School of Health Sciences, The University of Melbourne, Melbourne, VIC, Australia. Electronic address: kade.paterson@unimelb.edu.au.
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Paterson
The University of Melbourne, Department of Surgery, St Vincent's Hospital, Melbourne, Australia; The University of Melbourne, Department of Orthopaedics, St. Vincent's Hospital, Melbourne, Australia. Electronic address: mmdowsey@unimelb.edu.au.
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Dowsey
The University of Melbourne, Department of Surgery, St Vincent's Hospital, Melbourne, Australia; The University of Melbourne, Department of Orthopaedics, St. Vincent's Hospital, Melbourne, Australia. Electronic address: pchoong@unimelb.edu.au.
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Choong
Centre for Health, Exercise and Sports Medicine, Department of Physiotherapy, School of Health Sciences, The University of Melbourne, Melbourne, VIC, Australia. Electronic address: k.bennell@unimelb.edu.
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Bennell
D000368:Aged; D019645:Arthroplasty, Replacement, Knee; D001696:Biomechanical Phenomena; D018450:Disease Progression; D005260:Female; D005684:Gait / Q000502:physiology*; D006801:Humans; D007717:Knee / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D053580:Muscle Strength / Q000502:physiology; D020370:Osteoarthritis, Knee / Q000503:physiopathology* / Q000601:surgery; D052097:Quadriceps Muscle / Q000503:physiopathology
biomechanics; knee osteoarthritis; motion analysis; varus thrust