Functional outcomes post total knee arthroplasty following electrical muscle stimulation on the quadriceps muscle at Chris Hani Baragwanath Academic Hospital

Abstract

Background: Known as the largest hospital in the southern hemisphere, Chris Hani Baragwanath Academic Hospital caterers to a large volume of patients daily. Many of those patients need surgical procedures and a high turnover rate in relation to postoperative length of stay in hospital is the norm. However, some elective surgical procedures, such as total knee arthroplasty, have a prolonged hospital stay possibly due to the physiotherapy rehabilitation protocol being practiced. Aim: The aim of this study is to determine whether electrical muscle stimulation on the quadriceps muscle in addition to the normal physiotherapy rehabilitation protocol will influence the short-term functional outcomes at six weeks and length of stay in hospital post total knee arthroplasty when compared with the normal physiotherapy rehabilitation protocol at Chris Hani Baragwanath Academic Hospital. Method: A single blinded randomized controlled trial was conducted at Chris Hani Baragwanath Academic Hospital. Participants were selected from the patients, between 50 and 80 years of age, requiring total knee arthroplasty due to osteoarthritis during the period of September 2013 to August 2015. The study sample consisted of 52 participants who were randomly allocated into two groups to which the researcher was blinded. Both groups received the normal physiotherapy rehabilitation protocol. In addition, the experimental group (group one) started receiving electrical muscle stimulation 48 hours post-surgery, twice a day for ten minutes until discharge. Participants were measured for knee range of motion and quadriceps lag preoperatively, on discharge and at six weeks, using a standard goniometer. Quadriceps muscle strength was measured preoperatively and at six weeks using a hand-held dynamometer. Functional assessments were conducted using the Oxford Knee Score pre-operatively and at six weeks, and the Iowa Level of Assistance Scale performed daily until discharge. Results: All 52 (n=48 females and n=4 males) participants who met the inclusion and exclusion criteria consented to participate in this study. One participant, in the control group, demised due to medical complications whilst in hospital and no measurements were obtained on discharge and was therefore excluded from this study. The loss to follow up in both groups was particularly high at 38.1% (n=16 from a total of n=42) and 36.6% (n=15 from a total of n=41) for groups one (experimental group) and two (control group) respectively. The Oxford Knee Score showed no significant difference between the two groups preoperatively (p=0.55), and at six weeks (p=0.98). The Iowa Level of Assistance scale showed no significant clinical difference between the two groups on discharge (p=0.38). There was no significant clinical difference in length of stay in hospital between the two groups (p=0.38). There was no significant difference in active range of motion between the two groups pre-operatively (p=0.91), on discharge (p=0.80), and at six weeks (p=0.61). This study showed the same outcome for passive range of motion between the two groups preoperatively (p=0.89), on discharge (p=0.87), and at six weeks (p=0.63). The data revealed no significant clinical difference in quadriceps muscle strength between the two groups pre-operatively (p=0.31), and at six weeks (p=0.71). It was shown there was no significant difference in quadriceps lag between the two groups preoperatively (p=0.5). However, it was shown that the experimental group (group one), who had a median of 0 (0-0) quadriceps lag, yielded a significantly better outcome of quadriceps lag on discharge, than the control group (group two) who had a mean of 0 (0-5) quadriceps lag (p=0.0019). There is also a significant difference in quadriceps lag at six weeks, with a mean of 0 (0-0) in the experimental group (group one) and 0 (0-0) in the control group (group two) (p=0.04). There was a significant difference between the two groups with regard to days to reach 90 active and passive flexion (p<0.001), and 0 extension range of motion (p=0.0012). Conclusion: The addition of electrical muscle stimulation on the quadriceps muscle to the practiced protocol does not significantly influence the short-term functional

outcomes post total knee arthroplasty and did not significantly reduce the length of stay in hospital. The introduction of physiotherapy rehabilitation over the weekend did however, see a significant reduction in length of stay compared to previous statistics. Although there were some significant findings in this study, for now, electrical muscle stimulation should not be incorporated into the protocol currently being used a Chris Hani Baragwanath Academic Hospital, but with further research it could be re-looked. More research with electrical muscle stimulation should be done with more extended treatment sessions and follow ups at three and six months to determine the long-term effects of electrical muscle stimulation in this population, and, to determine if the results of this study is maintained or rendered unchanged.