Abstract
Introduction
As the aging society progresses rapidly, the number of patients underwent total knee arthroplasty (TKA) is increasing especially for the elderly population. In Japan, the average age for TKA is around 75 years old. Japanese Orthopaedic Association indicated a new clinical entity of musculoskeletal ambulation disability symptom complex (MADS) to define the higher risk of fall and ambulatory disability in the elderly population in 2006. The diagnosing criteria for MADS consists of 2 simple performance tests. 3m timed up and go test (TUG) evaluates ambulatory function, and one leg standing time (ST) assesses balancing ability.
Objective
In this study, we analyzed the effect of TKA on the ambulatory function by quantitative measurement using 2 simple performances test: TUG and ST.
Materials & Methods
Forty four patients (6 males and 38 females) with varus type osteoarthritic knees underwent TKA were involved. The mean age of surgery was 72.7 years old. TUG and ST were performed at 4 time periods; pre-operatively, 2 weeks after surgery, at hospital discharge (average 24.1 days) and 1year after surgery. Ambulatory disability (MADS) was diagnosed if TUG was not less than 11 seconds and/or ST was less than 15 seconds. 36 patients (82%) were diagnosed to MADS preoperatively. We divided these 36 patients into two groups depending on the performance tests one year after TKA. 24 patients (67%) still suffered from MADS (Group1), and remaining 12 patients (33%) recovered from MADS (Group2). We compared preoperative factors (age, femoro-tibial angle, ROM, etc.) and the results of ST and TUG between Group 1 and Group 2 using the Mann-Whitney test (p<0.05).
Results
The complication rates of MADS in all 44 patients were 82.0, 88.9, 83.3, and 55.6% at 4 time periods respectively. Significant functional recoveries were observed with decrease of TUG and increase of ST at 1 year after surgery (Fig. 1). Average age at surgery was significantly higher in Group 1 (74.7yo) comparing to Group 2 (69.3yo). The sequential change of mean TUG and ST at 4 time periods were shown for each group in Fig. 2 and Fig. 3. We found no significant difference in TUG but significant difference in ST between two groups. Patient in Group 2 could stand on one leg longer than Group 1 preoperatively even with no significant difference in TUG.
Discussions
We evaluated the ambulatory function using 2 simple performance tests, and found significant improvements in both balancing ability (ST) and ambulatory function (TUG) one year after TKA. However, more than 50% of our patient population still suffered from ambulatory disability (MADS) at 1 year after surgery. As much as 70% of preoperatively MADS complicated patients were found to meet MADS criteria even one year after TKA. Only 30% of preoperatively MADS complicated patient could recover from MADS. This group was relatively younger and showed better balancing ability preoperatively. Our results suggested that standing time measurement would be simple and useful predictor for the functional recovery after TKA.
