Date of Award
Master of Science
Health and Rehabilitation Sciences
Dr. Trevor B. Birmingham
Background: Medial opening wedge high tibial osteotomy (HTO) aims to improve
pain and function by correcting varus alignment and lessening aberrant medial compartment knee joint loads. Because varus gonarthrosis often affects both knees, staged bilateral HTO may be an appropriate treatment approach for such patients. However, we are unaware of any previous studies evaluating outcomes after these staged procedures.
Objectives: 1) To evaluate radiographic alignment, dynamic knee joint loading, performance-based and patient-reported outcomes after staged bilateral medial opening wedge HTO, and 2) To compare outcomes in patients undergoing the second surgery within, or beyond, 12 months of the first surgery.
Hypotheses: 1) Patients will experience statistically and clinically significant improvements in all measured outcomes; 2) Those patients undergoing the second surgery within 12 months of the first surgery will report greater improvements than those undergoing the second surgery beyond 12 months.
Study Design: Case Series; Level of evidence, 4 Methods: 37 patients with bilateral varus alignment (-8.36° ± 2.98°) and medial compartment osteoarthritis (OA) underwent staged bilateral medial opening wedge HTO. Patients underwent full-limb standing anteroposterior radiographs to determine frontal plane alignment (mechanical axis angle) and 3-dimensional gait analysis to estimate knee joint loading (external adduction moment about the knee). Patients also completed the six-minute walk test (6MWT), the Knee Injury and Osteoarthritis Outcomes Scores (KOOS), Lower Extremity Functional Scale (LEFS),
and the Short Form Health Survey [SF-12). Both limbs were evaluated for all measures preoperatively and approximately 6,12 and 24 months after each surgery.
Results: There were large improvements in outcomes. Mean changes (95%CI) were: mechanical axis angle 9.43° (8.37°, 10.39°); peak knee adduction moment -1.72 %BW*Ht [-2.06, -1.38 %BW*Ht); 6MWT 36.72 m [19.43, 54.01m); and KOOS Pain 25.60 [19.76, 31.44). There were no statistically significant differences in the improvements between those patients who had the second HTO within or beyond 12 months of the first HTO. Mean differences [95% Cl) were: mechanical axis angle 0.43° [-1.72°, 2.58°); peak knee adduction moment -0.20 %BW*Ht [-0.89, 0.49 %BW*Ht); 6MWT 15. 07 m [-19.79, 49.93m); and KOOS Pain -3.01 [ -14.55, 8.53). Conclusions: Patients experience large, clinically important improvements in frontal plane alignment, dynamic knee joint loading, and patient-reported outcomes after staged bilateral medial opening wedge HTO. Current findings suggest no difference in outcomes for patients who undergo the second surgery within, or beyond, 12 months of the first surgery.
Sischek, Emily Louise, "STAGED MEDIAL OPENING WEDGE HIGH TIBIAL OSTEOTOMY FOR BILATERAL VARUS GONARTHROSIS" (2011). Digitized Theses. 3523.