«Introduction»
Several preoperative risk factors for the survival rate of high tibial osteotomy (HTO) have been determined, which include the patient's age at surgery, female sex, and body mass index (BMI). The effect of the degree of preoperative osteoarthritis on the clinical outcome of HTO remains controversial.
«Objectives»
The purpose of this study was to evaluate the effect of the degree of osteoarthritis on mid-term to long-term outcome in HTO.
«Methods»
We reviewed 314 patients (385 patients) who had undergone closed wedge HTO. Twenty-eight knees had been converted to total knee arthroplasty (TKA), and 23 patients (26 knees) were excluded because of being died or severe dementia before this study was performed. The address of 31 patients (36 knees) were unknown. We mailed the 2011 Knee Society score (KSS2011) questionnaires to 234 patients (295 knees) and 158 patients (202 knees, 68.5%) returned a completed questionnaire. Fifty eight knees with the diagnosis of osteonecrosis were excluded from this study. Finally, we evaluated 109 patients (144 knees). The number of knees of preoperative Kellgren-Lawrence grade (K-L) 2, 3, and 4 were 16, 81 and 47 knees, respectively. Patient's data, including ages at the time of surgery, follow-up period, sex, preoperative BMI, preoperative and postoperative femorotibial angle (FTA), were collected from their medical records and radiographs. One-way Analysis of Variance (ANOVA), Turkey-Kramer test and chi-square test were used to analyze differences of KSS2011 between the groups.
«Results»
There were no significant differences in ages at the time of surgery, follow-up period, sex, and preoperative BMI between the groups (p > 0.05) . The mean follow up period was approximately 10 years. K-L 4 group showed larger preoperative FTA than other groups (p < 0.001). Among the KSS2011 sub-scores, K-L 4 group was significantly lower than K-L 2 (p = 0.008) and K-L 3 groups (p = 0.048) . In contrast, there were no significant differences in the satisfaction, expectation and total function scores between the groups (p > 0.05). In the comparison between K-L 2 and K-L 3 groups, there were no significant differences in all of sub-scores (p > 0.05).
«Conclusions»
This study showed that preoperative K-L grade affected the symptom significantly after HTO, while there are not significant differences in the satisfaction, expectation and total function scores between the groups. The preoperative advanced osteoarthritis can provide a negative effect to the clinical outcome in mid-term to long-term follow up after HTO.