Flexion contracture can be relieved by concurrent notchplasty in medial open wedge high tibial osteotomy

Abstract

tBackground: Given that medial open wedge high tibial osteotomy (OWHTO) not only delays the progres-sion of osteoarthritis but also alleviates the resulting pain, surgical outcomes would be improved if limitedROM can also be managed. In this regard, the effect of concurrent notchplasty on flexion contracture hasnot been evaluated.Hypothesis: (1) Concurrent notchplasty in OWHTO would relieve flexion contracture regardless of theseverity of osteoarthritis and this effect would be maintained over time, and (2) concurrent notchplastywould not cause any added complications compared to the same procedure without notchplasty.Patients and methods: In total, 107 patients who underwent OWHTO between 2011 and 2017 with amean follow-up period of 46.6 months (range: 24?102 months) were reviewed. ROM was measured atthree time points as follows: before surgery, at 6?12 months postoperatively, and at the latest follow-up. The measurements were analyzed using a linear mixed model in terms of notchplasty and otherfactors, including age, sex, body mass index, preoperative hip-knee-ankle angle, lateral distal femoralangle, medial proximal tibial angle, correction angle, concurrent meniscectomy, postoperative posteriorslope, and Kellgren?Lawrence grade. Then, ROMs at the three time points were compared between thenotchplasty and non-notchplasty groups.Results: Of the 107 patients, 47 underwent concurrent notchplasty. The linear mixed model regardingflexion contracture showed a significant notchplasty-by-time interaction (p < 0.001). When comparingpreoperative flexion contractures between the two groups, a significant difference was found (p < 0.001).At 6?12 months postoperatively, flexion contractures were relieved regardless of notchplasty; however,the difference between the groups was decreased (p = 0.026). At the latest follow-up, flexion contractureswere partly aggravated in both groups, but no significant difference was found between the groups(p = 0.461). Comparison of flexion contracture between before surgery and at the latest follow-up ineach group revealed a significant difference only in the notchplasty group (p < 0.001, with notchplasty;p = 0.197, without notchplasty). The linear mixed model regarding maximal flexion did not show anyfactor having a significant interaction with time. There were no surgical complications such as infection,thromboembolic events, and hemarthrosis, in both notchplasty and non-notchplasty groups.Conclusion: The preoperative difference in flexion contracture was overcome by adding notchplasty toOWHTO, and this improvement was maintained over time. No added complications were noted in thenotchplasty group. The results should be interpreted with caution, considering measurement error ofROM. However, concurrent notchplasty in OWHTO deserves further study to validate its efficacy.Level of evidence: III, retrospective cohort study.IRB information: Project No. S2020-0081, AMC IRB SOP.