Research Article: An easy and safe training method for trunk function improves mobility in total knee arthroplasty patients: A quasi-randomized controlled trial

Date Published: October 4, 2018

Publisher: Public Library of Science

Author(s): Yuki Sano, Akira Iwata, Hideyuki Wanaka, Mina Matsui, Saki Yamamoto, Junichiro Koyanagi, Hiroshi Iwata, Jose María Blasco.


Total knee arthroplasty (TKA) is aimed mainly at reducing pain and restoring mobility. However, mobility deficits can persist even longer than 1 year. The trunk function and movement velocity of any region have been recently recognized to be critical for determining mobility in older people. Therefore, the main goal of this quasi-randomized trial is to clarify the effectiveness of a novel training method, the seated side tapping (SST) training, for improving mobility by focusing on movement velocity of trunk function in the short term after TKA.

SST training consists of side trunk movements repeated as quickly as possible in a seated position. All participants after TKA were randomly assigned to the SST training group (n = 37) or control training group (n = 38). The participants in the SST group performed SST training plus the standard rehabilitation program 5 days per week for 3 weeks after TKA, while the control group performed only the standard rehabilitation programs. The primary outcome was the effect of SST training on mobility, indicated by gait speed and the timed up and go test (TUG) time. Measurements were performed before and 1, 2, and 3 weeks after surgery.

At all-time points, the patients in the SST group showed significantly better mobility, despite that knee function, represented by muscle strength, range of motion, and degree of pain at the knee joint, was similar in both groups. The difference in gait speed between the groups was >0.1 m/s at all time points, which is clinically significant.

SST training significantly improved patients’ mobility within 3 weeks after TKA, despite that no additional benefit was observed in knee function. The findings in this study indicate that SST training may be considered as a part of the rehabilitation program after TKA, although further evaluation of its long-term effectiveness is needed.

University Hospital Medical Information Network Clinical Trials Registry (UMIN-CTR; UMIN000027909).

Partial Text

Knee osteoarthritis (OA) is one of the most frequent causes of disability in older people, and total knee arthroplasty (TKA) is usually indicated as a surgical intervention for end-stage knee OA with the aims of pain relief, deformity correction, improvement of knee function, and restoration of locomotor function [1–3]. Even though TKA reduces pain and improves overall health-related quality of life in 90% of patients with a high patient satisfaction rate [4], recovery of locomotor function after TKA to a normal level is not common [5, 6]. A previous study demonstrated that patients 1 month after TKA had a 50% longer timed up and go test (TUG) time and walked 40% shorter distance in the 6-minute walking test than those before surgery [5]. Another study also showed that the gait speed of patients who underwent TKA was not fully recovered even at 1 year after TKA as compared with the age-matched controls [6]. To maintain or restore mobility after TKA, rehabilitation programs thus far have mainly focused on knee function, represented by knee joint pain [7], muscle strength of the quadriceps and hamstrings [8], and ranges of motion of knee flexion and extension [9].

A total of 105 participants provided informed consent for enrollment in this study before TKA (Fig 1). Among the participants enrolled, 24 were excluded from analysis because they could not walk without a walker for ≥10 m at 1 week after surgery. One participant in the SST group was excluded because of stroke after TKA, which required medical intervention. Two patients (1 in each group) did not complete the study course, as they were prematurely discharged at 2 weeks after TKA, which means that they had no data for the third week. Three participants were excluded for lack of data (1 in the SST group and 2 in the control group). After excluding 30 of the 105 original participants, 75 were finally included in the analysis. In this study, no adverse event caused by any rehabilitation training was reported. Among the 75 participants, 37 were assigned to the SST group and 38 to the control group. The proportions of participants by each surgeon were similar in each group, and no significant difference was observed in the chi-square test (p = 0.605; Table 1).

The purpose of this study was to assess the beneficial effects of SST training, which focuses on the quickness of trunk movement, on mobility in patients who had undergone TKA. As predicted, SST training produced a significant improvement in mobility as represented by gait speed and TUG time over the first 3 weeks after TKA, but no significant difference was observed in postoperative improvement in knee function, represented by knee range of motion and quadriceps and hamstrings muscle strengths. The differences in gait speed between the groups with and without SST training from the first to the third week after TKA were 0.13, 0.11, and 0.11 m/s, respectively. These values all exceed 0.1 m/s, which is generally accepted as a clinically relevant difference [21, 22]. We previously demonstrated that SST is a good indicator for predicting mobility in older people. Furthermore, this study suggests that SST training is an effective intervention with which to improve mobility in patients who have undergone TKA.




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