Surgical accuracy in high tibial osteotomy: coronal equivalence of computer navigation and gap measurement

Although knee malalignment is assumed to correlate with knee osteoarthritis (OA), it is still unknown whether malalignment precedes the development of OA or whether it is a result of OA. The aim of this study was to assess the relationship between malalignment and the development of knee OA as well as progression of knee OA. A total of 1,501 participants in the Rotterdam study were randomly selected. Knee OA at baseline and at followup (mean followup 6.6 years) was scored according to the Kellgren/Lawrence (K/L) grading system. Alignment was measured by the femorotibial angle on radiographs at baseline. Multivariable logistic regression for repeated measurements was used to analyze the association of malalignment with the development and progression of OA. Of 2,664 knees, 1,012 (38%) were considered to have normal alignment, 693 (26%) had varus alignment, and 959 (36%) had valgus alignment. A comparison of valgus alignment and normal alignment showed that valgus alignment was associated with a borderline significant increase in development of knee OA (odds ratio [OR] 1.54, 95% confidence interval [95% CI] 0.97-2.44), and varus alignment was associated with a 2-fold increased risk (OR 2.06, 95% CI 1.28-3.32). Stratification for body mass index showed that this increased risk was especially seen in overweight and obese individuals but not in non-overweight persons. The risk of OA progression was also significantly increased in the group with varus alignment compared with the group with normal alignment (OR 2.90, 95% CI 1.07-7.88). An increasing degree of varus alignment is associated not only with progression of knee OA but also with development of knee OA. However, this association seems particularly applicable to overweight and obese persons.

Varus and valgus alignment increase medial and lateral tibiofemoral load. Alignment was associated with tibiofemoral osteoarthritis progression in previous studies; an effect on incident osteoarthritis risk is less certain. This study tested whether alignment influences the risk of incident and progressive radiographic tibiofemoral osteoarthritis. In an observational, longitudinal study of the Multicenter Osteoarthritis Study cohort, full-limb x-rays to measure alignment were acquired at baseline and knee x-rays were acquired at baseline and knee x-rays at baseline and 30 months. Varus alignment was defined as ≤178° and valgus ≥182°. Using logistic regression and generalised estimating equations, the associations of baseline alignment and incident osteoarthritis at 30 months (in knees without baseline osteoarthritis) and alignment and osteoarthritis progression (in knees with osteoarthritis) were examined, adjusting. For age, gender, body mass index, injury, laxity and strength, with neutral knees as referent. 2958 knees (1752 participants) were without osteoarthritis at baseline. Varus (adjusted OR 1.49, 95% CI 1.06 to 2.10) but not valgus alignment was associated with incident osteoarthritis. 1307 knees (950 participants) had osteoarthritis at baseline. Varus alignment was associated with a greater risk of medial osteoarthritis progression (adjusted OR 3.59, 95% CI 2.62 to 4.92) and a reduced risk of lateral progression, and valgus with a greater risk of lateral progression (adjusted OR 4.85, 95% CI 3.17 to 7.42) and a reduced risk of medial progression. Varus but not valgus alignment increased the risk of incident tibiofemoral osteoarthritis. In knees with osteoarthritis, varus and valgus alignment each increased the risk of progression in the biomechanically stressed compartment.

To systematically review the evidence for a relationship between malalignment of the knee joint and progression and/or development of knee osteoarthritis (OA). Electronic searches of Medline, EMBase, and CINAHL were performed up to July 2008 using medical subject headings and free-text words. We included radiographic or magnetic resonance imaging (MRI) studies that met a set of predefined criteria. Two independent reviewers extracted the data and assessed the methodologic quality of the selected studies. Due to both heterogeneity and a limited number of studies, the results were summarized using a best evidence synthesis. Fourteen studies met our inclusion criteria and 8 were considered high quality. We found limited evidence for an association between knee malalignment and incident knee OA, because only 1 cohort study examined this relationship. However, there was strong evidence based on 4 high-quality cohort studies that knee malalignment is an independent risk factor for progression of radiographic knee OA. This finding was further supported by 2 high-quality MRI cohort studies that found a relationship between varus and valgus alignment and structural progression of knee OA. Malalignment of the knee joint was found to be an independent risk factor for the progression of knee OA. Given the paucity of investigation into the relationship between knee malalignment and risk of incident OA, further high-quality cohort studies are needed, and these may have important implications for the prevention of knee OA.