Mid-term results of high tibial osteotomy for medial compartment arthritis using hemicallostasis by dynamic external fixator

Abstract

Introduction: Medial Gonarthrosis of Knee in middle-aged (40-60yrs) physically active individuals has become a considerable cause for pain, immobility and disability. Varus malalignment at knee joint compromises biomechanics and sets up a vicious cycle which leads to progressive deterioration of medial compartment. Medial open-wedge osteotomy using dynamic external fixator is a recent procedure introduced for axis correction and restoring joint biomechanics with good clinical results. Material and Methods: We retrospectively reviewed 75 patients (78 knees) who were operated for medial compartment arthritis by High Tibial Osteotomy using Hemicallostasis between 2001-2007. Preoperative full length Hip knee axis standing radiographs were taken and femoro-tibial angle determined. Medial open wedge osteotomy using dynamic external fixator was done and axis correction by gradual distraction was achieved to desired angle. Post-operative full length radiographs were compared and evaluated. Oxford Knee Score was used as a clinical tool for assessment. Results: In a mean follow-up period of 83 months, 54% patients showed excellent outcome with improved Oxford knee score. Most significant improvement was observed in females aged 51-60 years. Amongst 75 patients, 11 patients encountered pin-track infection, 4 patients had delayed union, 1 patient had lateral cortical fracture, and 7 patients had knee stiffness. No patients had loss of reduction or non-union of osteotomy site. No patients had conversion to total knee arthroplasty till last follow-up. Conclusion: High Tibial Osteotomy using dynamic external fixator provides cheap alternative in young active patients with initial stages of Medial Compartment Arthritis with good survivorship, no internal implant, less difficulty in subsequent total knee arthroplasty, minimal scar, minimal tissue disturbance, re-usability of fixator frame and good long-term results.