Abstract
Introduction
Total knee arthroplasty (TKA) has traditionally been performed as an effective treatment for patients with end-stage knee OA, by relieving pain, restoring function, and correcting deformity. One-leg standing (OLS) test is a widely used clinical tool to evaluate postural steadiness in a standing position for elderly people. According to previous reports, one-leg standing time was associated with subjects' age, self-assessment of their health status, body mass index, mortality, and the risk of falls. Therefore, it is important to know knee condition including OLS in older patients with knee OA. However, it is unknown whether TKA will be really beneficial for OLS in the elderly people.
It was hypothesized that postoperative recovery would be more slowly in older patients than in younger patients. Our purpose was to investigate factors affecting the OLS time in patients with end-stage knee OA and to clarify an age-related recovery process following TKA in the early postoperative period.
Methods
A total of 80 knees in 40 patients (35 females and 5 males) were enrolled in the current investigation. Mean age was 75 (60–82) years old. All the patients had bilateral varus deformities with radiographic OA of grade 4 severities, according to Kellgren-Lawrence grade. All the patients were divided into 2 Groups; patients older than 76 years (Group O) and younger than 75 years (Group Y). After unilateral TKA using Balanced Knee System®, posterior stabilized design (Ortho Development, Draper, UT), postoperative evaluations including OLS time, knee flexion angle during standing (KFA), and Visual Analogue Scale (VAS), were done preoperatively and daily from postoperative day 3 to 20 in each group, because epidural catheter was removed on postoperative day 2.
As a statistical analysis, values of preoperative measurements were used as controls in each group. Statistical difference between the data was evaluated using two-tailed repeated-measures of analysis of variance (ANOVA). After a significant P value (< 0.05) was determined, a post hoc Dunnett test was performed to compare selected mean values, and P-values of < 0.05 was considered as significant.
Results
20 patients (mean 78 years old) were allocated to Group O and 20 patients (mean 69 years old) were allocated to Group Y. In terms of preoperative demographic data, no significant differences were detected between the two groups. Evaluation of change in VAS, KFA, and OLS were presented in Figure 1, 2, and 3, respectively. Similar pain reduction and similar improvement of KFA were observed in both Groups. On the other hand, significant differences were detected between both groups in OLS time.
Discussion
In terms of OLS, according to previous reports, OLS balance in patients with knee OA improved significantly 11 days after TKA in younger patients (mean 61 years). However, unfortunately, OLS time in older patients did not improve for 20 days after TKA. Specifically, longer rehabilitative period was required in older patients than in younger patients for significant recovery of OLS time. Therefore, risk of falling still exists especially for older patients in the early postoperative period after TKA.
