Coronal tibiofemoral subluxation is a risk factor for postoperative overcorrection in high tibial osteotomy.

Abstract

BACKGROUND\nSevere tibiofemoral (TF) subluxation >\u202f10\u202fmm is a contraindication for high tibial osteotomy (HTO). However, the relationship between the degree of preoperative TF subluxation at <\u202f10\u202fmm and postoperative radiographic/clinical outcomes remains unclear.\n\n\nMETHODS\nSixty-seven patients who underwent open wedge HTO with a planned postoperative mechanical femorotibial angle (mFTA) of three degrees valgus were retrospectively studied. The minimal subluxation (MIN) group included 39 patients with TF subluxation <\u202f5\u202fmm, while the moderate subluxation (MOD) group included 28 patients with TF subluxation of five to 10\u202fmm. The preoperative and one-year postoperative mFTA, TF subluxation, medial proximal tibial angle (MPTA), joint line convergence angle (JLCA), preoperative Kellgren-Lawrence (K-L) grade and varus-valgus laxity were evaluated. Clinical scores and pain visual analogue scale (VAS) were also analyzed.\n\n\nRESULTS\nThe mean preoperative TF values in the MIN and MOD groups were 3.1±1.0 mm and 6.7±1.6 mm (mean±standard deviation, p\u202f<\u202f0.001), respectively, with no significant difference in K-L grades. The MIN group demonstrated a significantly smaller varus preoperative mFTA (p\u202f<\u202f0.001), larger MPTA (p\u202f=\u202f0.011), smaller JLCA (p\u202f=\u202f0.004), and less varus laxity (p\u202f=\u202f0.023). Postoperative TF subluxation, MPTAs, and JLCAs did not differ significantly between the two groups, while the postoperative mFTA was significantly different (p\u202f=\u202f0.001), with unintended overcorrection in the MOD group. No significant difference in clinical scores and VAS were observed.\n\n\nCONCLUSIONS\nAfter HTO, compared to patients with TF subluxation <\u202f5\u202fmm, patients with TF subluxation of five to 10\u202fmm were more likely to demonstrate unintended valgus overcorrection on one-year postoperative radiography.