Abstract: Introduction: Medial compartment osteoarthritis is a common entity leading to significant morbidity in geriatric population. High tibial osteotomy is a time tested knee preserving operation. The fixation methods vary from internal fixation like plates and screws, to external fixators like dynamic uniaxial fixators and Ilizarov.
In this study we have analysed the outcomes of medial opening wedge osteotomy using a unilateral dynamic external fixator (Orthofix) using the principle of hemi-callostasis.
Method: We conducted a prospective cohort study involving 20 patients with medical compartment osteoarthritis. Medial HTO was performed using OrthofixTM external fixator in 20 patients (20 knees) and were followed up between January 2019 to February 2021.Functional and radiological outcomes were assessed using the KSS and KOOS scores and the alignment xrays respectively.
Results: Out of 20 patients included in the study, the majority (18) were females the mean age in the group was 50.75 years (+6.06years) at time of surgery. The involvement of right knee was seen in 12 patients and left knee was involved in 8 patients. The average improvement in th HKA was 13+1.2 degrees. The Average corrected HKA was 183.05+4.2 degrees. There was significant improvement in the mean KSS score at 2years, from (44.15 ± 6.13) pre-operatively to (86.15 ± 6.41) post-operatively and was statistically significant (p<0.001). An average KOOS score was (45.81±4.38) pre-operatively which improved to (89.20±4.24) in the post-operative period which was statistically significant (p < 0.001).
There was positive correlation between pre and post operative KSS values which was significant at p < 0.05 that is, patients with better pre operative KSS scores had Better post operative functional outcome.
Conclusion: High tibial osteotomy is a good option for young physiologically active patients with medial compartment osteoarthritis. The dynamic external fixator allows accurate correction of HKA angle postoperatively. Appropriate patient selection, good pre-operative planning, patient education and precise surgical techniques are essential for success of HTO. Achieving HKA angle between 183 -186 degrees is the key for good functional outcome and pain relief.
