Factors characterizing gait performance of patients before and soon after knee arthroplasty.

[Purpose] For monitoring patients with knee osteoarthritis undergoing knee arthroplasty, the Timed Up and Go and maximum walking speed tests are commonly used. To provide appropriate peri-surgical rehabilitation, we evaluated the factors associated with postsurgical changes in Timed Up and Go and maximum walking speed results. [Participants and Methods] We enrolled 545 knee osteoarthritis patients undergoing either of the following knee arthroplasties: conventional total knee arthroplasty, minimally invasive total knee arthroplasty, and unicompartmental knee arthroplasty. Comfortable Timed Up and Go, maximum Timed Up and Go, and maximum walking speed were measured 2 weeks before and soon after surgery. Factors (gender, age, and surgical mode) that might influence changes in test results were evaluated by multiple regression analysis and a two-factor stratification diagram. [Results] Multiple regression analysis revealed that postsurgical changes in comfortable/maximum Timed Up and Go and maximum walking speed results were associated with age and surgical mode after adjustment for preoperative values. Two-factor diagrams showed that the older the patient, the greater was the slowdown in the Timed Up and Go test performed postoperatively. The levels of slowdown in the postoperative Timed Up and Go and maximum walking speed tests were the smallest in those who underwent conventional total knee arthroplasty, followed by those who underwent minimally invasive and unicompartmental knee arthroplasty. Among patients whose preoperative Timed Up and Go and maximum walking speed were slow, slowdown in Timed Up and Go was pronounced with age, and slowdown in maximum walking speed was higher in conventional total knee arthroplasty. [Conclusion] The changes in Timed Up and Go and maximum walking speed results 2 weeks after knee arthroplasty depended on age and surgical modes. These findings are relevant for the implementation of appropriate peri-surgical rehabilitation.

Determination of reference intervals for knee motor functions specific to patients undergoing knee arthroplasty.

BACKGROUND: In patients with knee osteoarthritis (KOA) undergoing knee arthroplasty (KA), lower-limb motor function tests are commonly measured during peri-surgical rehabilitation. To clarify their sources of variation and determine reference intervals (RIs), a multicenter study was performed in Japan. METHODS: We enrolled 545 KOA patients (127 men; 418 women; mean age 74.2 years) who underwent KA and followed a normal recovery course. The surgical modes included total KA (TKA), minimally invasive TKA (MIS-TKA), and unicompartmental KA (UKA). Motor functions measured twice before and two weeks after surgery included timed up-and-go (TUG), maximum walking speed (MWS), extensor and flexor muscle strength (MS), and knee range of motion (ROM). Multiple regression analysis was performed to evaluate their sources of variation including sex, age, BMI, and surgical mode. Magnitude of between-subgroup differences was expressed as SD ratio (SDR) based on 3-level nested ANOVA. SDR≥0.4 was set as the threshold for requiring RIs specific for each subgroup. RESULTS: Before surgery, age-related changes exceeding the threshold were observed for TUG and MWS. Between-sex difference was noted for extensor and flexor MS, but extension and flexion ROMs were not influenced by sex or age. After surgery, in addition to similar influences of sex and age on test results, surgical modes of UKA and MIS-TKA generally had a favorable influence on MWS, extensor MS, and flexion ROM. All motor function test results showed a variable degree of skewness in distribution, and thus RIs were basically derived by the parametric method after Gaussian transformation of test results. CONCLUSIONS: This is the first study to determine RIs for knee motor functions specific to KOA patients after careful consideration of their sources of variation and distribution shapes. These RIs facilitate objective implementation of peri-surgical rehabilitation and allow detection of patients who deviate from the normal course of recovery.

A clinical prediction rule for predicting a delay in quality of life recovery at 1 month after total knee arthroplasty: A decision tree model.

BACKGROUND: There is no clinical prediction rule for predicting the prognosis of quality of life after total knee arthroplasty and for assessing its accuracy. The study aimed to develop and assess a clinical prediction rule to predict decline in quality of life at 1 month after total knee arthroplasty. METHODS: This study included 116 patients with total knee arthroplasty in Japan. Potential predictors such as sociodemographic factors, medical information, and motor functions were measured. Quality of life was measured using the Japanese Knee Osteoarthritis Measure at 1 day before surgery and 1 month after total knee arthroplasty. The classification and regression tree methodology was used for developing a clinical prediction rule. RESULTS: The Japanese Knee Osteoarthritis Measure score pre-total knee arthroplasty (≦34.0 or >34.0) was the best single discriminator. Among those with the Japanese Knee Osteoarthritis Measure score pre-total knee arthroplasty ≦34.0, the next best predictor was knee flexor muscle strength on the affected side (≦0.45 or >0.45 N m/kg). Among those with knee flexor muscle strength on the affected side >0.45, the next predictor was knee flexion range of motion on the affected side (≦132.5°or >132.5°). The area under the receiver operating characteristic curves of the model was 0.805 (95% confidence interval, 0.701-0.909). CONCLUSIONS: In this study, 4 variables were selected as the significant predictor. However, the results of knee flexor muscle strength and knee flexion range of motion were paradoxical. This result suggests that it should be careful to perform surgery to the patients with good preoperative knee function. The clinical prediction rule was developed for predicting quality of life decline 1 month after total knee arthroplasty, and the accuracy was moderate. This clinical prediction rule can be used for screening of patients with total knee arthroplasty.

Do Sociodemographic Factors Relate to Walking Ability in Individuals Who Underwent Total Knee Arthroplasty?

BACKGROUND AND PURPOSE: Knee osteoarthritis is one of the most common health problems in older adults and total knee arthroplasty (TKA) is able to improve walking ability in these individuals. There have been few studies investigating whether sociodemographic factors influence walking ability after TKA. The aim of this study was to examine which sociodemographic factors relate to walking ability in Japanese older adults following TKA during the acute stage of recovery. METHODS: This prospective cohort study included 388 participants, from a multicenter database, who underwent TKA. The Timed Up and Go test 2 weeks after TKA was the dependent variable. Sociodemographic factors including age, sex, body mass index, marital status, and academic qualification were independent variables. In addition, type of surgery and severity of osteoarthritis were measured as confounding variables. A hierarchical multiple regression analysis was used to predict the factors that have the greatest influence on walking ability. Models were examined with and without confounding factors. RESULTS AND DISCUSSION: In the final regression model, older age, conventional TKA approaches, increased severity of Kellgren-Lawrence grade, and women were associated with longer Timed Up and Go time. Academic qualification and marital status were not related to walking ability. CONCLUSIONS: Our results suggest that age, type of surgery, severity of osteoarthritis, and sex are related to Timed Up and Go time during the acute stage following TKA and need to be assessed.

Quantifying walking ability in Japanese patients with knee osteoarthritis: Standard values derived from a multicenter study.

BACKGROUND: We aimed to determine useful parameters for quantifying walking ability in patients with knee osteoarthritis. METHODS: This study included 621 Japanese patients with knee osteoarthritis scheduled to undergo total knee arthroplasty at any of 14 participating hospitals. Sex, age, body mass index, osteoarthritis severity (Kellgren-Lawrence grade), laterality, prior contralateral surgery, and pain were analyzed for their influence on walking ability, which was evaluated in terms of the 5-m walk test and the Timed Up and Go test outcomes during preoperative hospitalization. Patients were stratified based on dichotomized values of the independent influencing factors of walking ability, and the standard values for parameters describing walking ability were obtained. RESULTS: Multiple regression analysis revealed that sex, age, and Kellgren-Lawrence grade were factors influencing walking ability (5-m walk test and Timed Up and Go test outcomes). Therefore, the patients were stratified by sex, age, and Kellgren-Lawrence grade. The standard values (median values) for walking time on the 5-m walk test among patients aged 60-74/75-89 years were: 3.90/4.64 vs. 4.27/5.12 s for men vs. women with Kellgren-Lawrence grade III; 4.26/5.60 vs. 4.80/6.05 s for men vs. women with Kellgren-Lawrence grade IV. Regarding walking speed on the 5-m test, the standard values were: 1.28/1.08 vs. 1.17/0.98 m/s for men vs. women with Kellgren-Lawrence grade III; 1.17/0.89 vs. 1.04/0.83 m/s for men vs. women with Kellgren-Lawrence grade IV. Finally, the standard values for time on the Timed Up and Go test were: 8.52/10.30 vs. 9.30/11.74 s for men vs. women with Kellgren-Lawrence grade III; 9.40/12.90 vs. 10.05/13.20 s for men vs. women with Kellgren-Lawrence grade IV. CONCLUSIONS: The standard values reported in this study can be used to quantify walking ability decline in patients with knee osteoarthritis and to aid in the decision to consider total knee arthroplasty.

Factors for Assessing the Effectiveness of Early Rehabilitation after Minimally Invasive Total Knee Arthroplasty: A Prospective Cohort Study.

The effectiveness of current rehabilitation programs is supported by high-level evidence from the results of randomized controlled trials, but an increasing number of patients are not discharged from the hospital because of the schedule of the critical path (CP). The present study aimed to determine which factors can be used to assess the effectiveness of early rehabilitation. We enrolled 123 patients with medial knee osteoarthritis (OA) who had undergone unilateral minimally invasive total knee arthroplasty for the first time. The following factors were assessed preoperatively: the maximum isometric muscle strength of the knee extensors and flexors, maximum knee and hip joint angle, pain, 5-m maximum walking speed, sex, age, body mass index, exercise habits, Kellgren-Lawrence grade, femorotibial angle, failure side (bilateral or unilateral knee OA), and functional independence measure. We re-evaluated physical function (i.e., muscle strength, joint angle, and pain) and motor function (5-m maximum walking speed) 14 days postoperatively. Changes in physical function, motor function (5-m maximum walking speed), and number of days to independent walking were used as explanatory variables. The postoperative duration of hospitalization (in days) was used as the dependent variable in multivariate analyses. These analyses were adjusted for sex, age, body mass index, exercise habits, Kellgren-Lawrence grade, femorotibial angle, failure side, and functional independence measure. The duration of hospitalization was significantly affected by the number of days to independent walking (p < 0.001, ß = 0.507) and a change in the 5-m maximum walking speed (p = 0.016, ß = -0.262). Multiple regression analysis showed that the radiographic knee grade (p = 0.029, ß = 0.239) was a significant confounding factor. Independent walking and walking speed recovery were considered to reduce the duration of hospitalization. Therefore, these indices can be used to assess the effectiveness of early rehabilitation.