Failure of high tibial varus osteotomy for lateral tibio-femoral osteoarthritis with<10° of valgus: Outcomes in 19 patients.

BACKGROUND: Osteotomy is a rational approach to slowing knee osteoarthritis progression by modifying loads, thereby avoiding joint replacement in younger individuals. Varus femoral osteotomy is recommended only in patients with more than 10° of valgus. The objective here was to assess outcomes of tibial varus osteotomy in patients with lateral compartment tibio-femoral osteoarthritis and less than 10° of valgus. The hypothesis was that high tibial varus osteotomy produces satisfactory and long-lasting improvements.

MATERIAL AND METHODS: A single-centre retrospective study was conducted in 19 consecutive patients managed by high tibial varus osteotomy between January 2005 and May 2012. Mean age was 54.5years. The clinical IKS knee and function scores and radiological parameters were determined pre-operatively then after 6 and 12months and at last follow-up. The primary outcome measure was the global IKS score. Failure was defined as a global IKS score <140 or total knee arthroplasty (TKA). Secondary outcome measures were a post-operative hip-knee-ankle (HKA) angle between 180° and 183° and less than 10° of joint line obliquity. The hypothesis was that high tibial varus osteotomy produced satisfactory and long-lasting improvements in lateral compartment tibio-femoral osteoarthritis.

RESULTS: After the mean follow-up of 4.3years (range, 2-9years), 10/19 patients had a global IKS score <140. Among them, 7 underwent TKA after a mean of 5.0±2.7years. Varus tibial osteotomy was followed by significant improvements in the IKS knee and function scores from baseline to last follow-up (P<0.05). A global IKS<140 predicted TKA. Mean HKA angle values were 186.3±2.9° pre-operatively and 181.3°± 3.9°at last follow-up (P<0.05); the HKA angle was within the 180°-183° range in 8 (42.1%) patients. Mean post-operative joint line obliquity was 7.8±3.0°. An HKA angle outside the 180-183° range and joint line obliquity >10° were associated with poor outcomes.

DISCUSSION: High tibial varus osteotomy produces unsatisfactory medium-term outcomes, with an overall failure rate of 52%. At present, high tibial varus osteotomy has no role in the management of lateral compartment tibio-femoral osteoarthritis with <10° of valgus.

LEVEL OF EVIDENCE: IV, retrospective cohort study.