Changes in lower limb alignment and their effect on the functional outcome after treatment of varus degenerative OA knee by hemicallotasis using modular dynamic HTO fixator

Abstract

Medial opening wedge high tibial osteotomy (MOWHTO) Femoro tibial angle (FTA) Mechanical axis KOOS Medial compartment OA Knee Varus knee a b s t r a c tObjective: High tibial osteotomy (HTO) is an established procedure to treat medial compartmental osteoarthritis (OA) knee associated with varus deformity. It is well documented that precise correction of deformity and maintenance of correction achieved is important to ensure long term good results. This study was undertaken to record changes in radiological parameters and its effect on the functional outcomes in first two years following HTO done for varus degenerative OA kneeby hemicallotasis technique using HTO fixator. Methods: 31 patients meeting our inclusion-exclusion criteria who underwent HTO by hemicallotasis method using self-adjusting unilateral HTO fixator were included in the study. Their femoro tibial angle (FTA), mechanical axis %, Insall-Salvati ratio, proximal tibial antero-posterior slope and knee injury and osteoarthritis outcome Score (KOOS) were recorded preoperatively, postoperatively at the time of removal of fixator, at 1 year and at 2 years. Results: The FTA and mechanical axis significantly improved from a mean of 183.12⁰ and À3.26% respectively preoperatively to 173.38⁰ and 61.81% at the time of removal of fixator but subsequently showed significant deterioration to 176.06⁰ and 57.96% at 1 year and further insignificant deterioration to 176.16⁰ and 57.74 at 2 years. The KOOS improved from mean 56.61 preoperatively to 70.48 at the time of fixator removal and further improved significantly to 85.68 at 1 year but significantly deteriorated to 84.54 at 2 years. The Insall-Salvati ratio, tibial slope showed no significant change throughout the study. Conclusion: Though desired alignment can be achieved by using the fixator, we found a significant deterioration in achieved radiological parameters after removal of fixator adversely affecting the functional outcome which is a matter of concern.

Medial open-wedge high tibial osteotomy for the treatment of degenerative varus knee osteoarthritis in geriatric patients: a retrospective study

“…Lee et al have conducted an investigation and evaluated the influence of age on survivorship and complications after HTO, there were 41,112, 13,895 and 6138 patients underwent HTO under 60 years (Group A), between 60 and 65 years (Group B) and older than 65 years (Group C), results showed that overall revision rate was 4.2%, 6.4% and 7.3% for Group A, B, C. The 5- and 10-year revision rate and incidence of complication were significantly lower in Group A 11 . However, other studies also reported good outcomes of HTO in geriatric patients, Hrishikesh and his colleagues analyzed the functional changes of varus degenerative OA knee by hemicallotasis using modular dynamic HTO fixator, mean age of the study population in their research was 49.3 years with a maximum of 67 years, the KOOS improved from mean 56.61 preoperatively to 70.48 at the time of fixator removal, and after 1-year follow-up, KOOS score further improved significantly to 85.68 12 . It is well accepted that a mildly degenerative KOA is usually accompanied by better clinical outcomes of HTO, therefore, we performed OWHTO in patients with K–L grade up to III, and 77.6% of the OWHTO patients in our study were assessed as grade I or II of K–L grade.…”