INTRODUCTION:

Osteoarthritis is defined “as a group of overlapping distinct diseases, which have different etiological explanations but with similar biological, morphologic and clinical outcomes. The disease processes not only affect the articular cartilage, but involve the entire joint, including the subchondral bone, ligaments, capsule, synovial membrane and periarticular muscles. Ultimately, the articular cartilage degenerates with fibrillation, fissures, ulceration and full thickness loss of the joint surface”.^[1]Obese individuals are observed to have a greater risk and severity of osteoarthritis due to reduced physical activity, decreased muscle strength and increased joint compression.^[2]About 40-50% of the knee osteoarthritis are evident among younger individuals due to trauma such as meniscal tear and ligamentous injury of the knee incurred at younger age due to sporting activity.^[3] Osteoarthritis is a disease which causes a huge burden on the population. Osteoarthritis imposes a huge burden to the people which are measured by direct costs, indirect costs and intangible costs. Direct costs are usually attributed to the various forms of treatment, indirect costs arises due to reduced employment, reduced productivity, absenteeism and premature mortality. The main attribute for intangible costs are pain, fatigue, activity limitation and decreased quality of life.^[4]Conventional Physiotherapy encompasses a number of treatment modalities which includes electrotherapy, exercise therapy, aquatic therapy, manual therapy, knee taping and patient self-education. American college of rheumatology and European league against rheumatism recommend physiotherapy as non-pharmacological intervention for knee osteoarthritis.^[5,6]Strong evidence supports the beneficial effects of physiotherapy in any form over pain and knee function.The advantage of isokinetic training is that, it allows performance of exercise at a specific angular velocity and resistance modification according to the participant‟s effort. This enables the participant to perform full range of motion with the maximum muscular contraction.^[7] Since isokinetic dynamometers offers a safer environment for the performance of evaluation and exercise, it has been extensively used in the field of rehabilitation, training and also in the evaluation of musculoskeletal performance.Isokinetic device has been known to measure the strength of the muscle much more precisely. The peak torque during concentric contraction and eccentric contraction of the agonist and antagonist muscle have been used accurately measured and used in the field of sports and orthopedic rehabilitation.^[8,9,10] Isokinetic training has been used in participants with osteoarthritis of knee to measure improvements in the strength and functional outcomes.^{[11,12,13,14]}Various meta-analytic reviews have reported conflicting results.^[15,16]EMG aided training has been an adjunct to other forms of rehabilitation in various orthopaedic crises of knee. Researchers have been using EMG aided training to aid in the recovery of quadriceps muscle function. Previous reports depicting the effect of EMG aided training on knee disorders have been inconclusive. There are literatures that have reported a positive effect i.e improvement in knee functional outcomes and quadriceps strength^[17-23], negative effects^[24,25] and no effect^[26-29]. Meta analytic review have reported reduction in pain but no improvement in strength of the muscle.^[30]. This study intends to compare the effects of physiotherapy, isokinetic training and EMG Biofeedback training on improving the strength of the quadriceps femoris in patients with osteoarthritis of knee.

METHODOLOGY:

Patients:

A double blinded randomised control trial was chosen. The sample size was calculated using G power version (3.1). About 54 participants based on the inclusion criteria such as (American college of rheumatology criteria, severity of Grade II and Grade III according to Kellgren-Lawrence criteria^[31], unilateral osteoarthritis and females who have attained menopuase) were sent to the researcher for further assessment. Participants with secondary osteoarthritis,bilateral osteoarthritis, could not attend the training session were excluded from the study.Informed consent was obtained from the participants once the participants confirmed their participation in the present study. The procedure of the study was in accordance with the Helsinki Declaration^[32] of 1975 as revised in 1983. The male participants were about 14 in number and the female participants amounted to 40 participants. The age range of the participants was 50 - 66 years. The study was conducted at Exercise and Sports Science laboratory, School of Health Sciences and Skills laboratory, School of Medical Sciences, Universiti Sains Malaysia.The present study was undertaken after the approval of the ethical committee of Universiti Sains Malaysia. The experimenter had a prior discussion with the orthopedic surgeons of the Department of Orthopedics, Hospital Universiti Sains Malaysia. The participants were identified by the orthopedist (who was blinded to the study) based on the inclusion criteria and were thoroughly examined. This process was followed by radiological examination of the participants to confirm the severity of Osteoarthritis with an X- ray. The participant was taken to the exercise and sport science laboratory for the baseline assessments.

Outcome measurements:

The weight, height and BMI of the participants were measured and recorded. A baseline measurement of strength (average peak torque) was done using isokinetic device (Isokinetic Biodex 4 Multi-Joint System Pro Machine) using standard guidelines adopted by respective test devisors. The velocity was set at 180 degree since high velocity reduces friction within the arthritic joint thereby reducing the chance of occurrence of pain. A concentric–concentric mode was set for the measurement of these parameters ^[12]. A prior warm up of stretching and cycling for 2 minutes was performed for the lower limb. Once the participant was ready, on the command of „GO‟ the participant was requested to push as hard as possible against the lever of the dynamometer. Participants performed 5 repetitions of concentric contraction for knee flexors and extensors followed by a rest for 30 seconds and then 15 repetitions of the same.^[33]

On completion of the baseline assessment, the participants were randomized using Research Randomizer (Version 4.0) [Computer software].^[34] Based on the random sampling all of the participants were categorized into three groups–1) Group A– Control group (received Conventional Physiotherapeutic intervention) (n=18); 2) Group B–Experimental Group I, received Isokinetic Training (n=18) consisting of 3 males and 15 females; 3) Group C– Experimental Group II, received EMG Biofeedback training (n=18). The allocation was concealed.Participants of Group A received Conventional Physiotherapy exercise program following the standardized physiotherapeutic intervention protocol which were progressed after 2 weeks.

Conventional Physiotherapy protocol:

The Conventional Physiotherapeutic intervention used in this study comprised of exercises in three categories. The three categories of exercises are;

1. Strengthening exercises.

2. Stretching exercises.

3. Range of Motion exercise.

These exercises were performed in accordance with the study performed by Deyle et al., (2005).^[35]

1. Strengthening Exercises:

Strengthening exercises consisted of exercises that strengthen mainly the quadriceps femoris, exercises that strengthen only the hamstring or exercises that strengthen both these muscle. The exercises that were performed by the participants were a) static quadriceps in knee extension, b) standing terminal knee extension, c) seated leg press, d) partial squat weight-lessened with arm support as needed and e) step-up.

2. Stretching exercises:

The stretching exercises that were prescribed to the participants

a. Standing calf stretch;

b. Supine hamstring muscle stretch ;

c. Prone quadriceps femoris muscle stretch;

3. Range of Motion exercise:

Range of motion exercise performed in this study consists of exercise in which the knee is moved from a) mid-flexion to full-extension b) mid-flexion to full-flexion and c) modified cycling motion

Isokinetic training:

Group B received Isokinetic Training following the standardized protocol 5-Concentric and eccentric contraction for knee extensors, 5-Eccentric and concentric for knee flexors at (90°/sec and 150°/sec) of 60% average peak torque progressed to 20-Concentric and eccentric contraction for knee extensors, 20-Eccentric and concentric for knee flexors at (90°/sec and 150°/sec) of 60% average peak torque. The protocol of the present study was based on the works done by Huang et al., (2005).^[10] The protocol consisted of warm up session of 3-5 minutes cycling on a stationary bicycle without resistance or modified cycling motion, stretching of the quadriceps and hamstrings for 3 repetitions and 30 seconds hold during each repetition. The training was performed twice per week for 10 weeks totalling to 20 sessions. After every two weeks of training the repetitions were increased progressively. Participants were allowed 30 seconds of rest between sets.The researcher of the present study preferred a high velocity of 90°/second and 150°/second since the friction of the joint will reduce once the velocity increases.^[36]

EMG Biofeedback Training:

Group C received EMG Biofeedback training following standardized protocol.The setting up of the equipment Mega ME 6000 and fixing of electrodes were done prior to the commencement of the exercises. Prior instructions about the exercises and initial trials were also done. The placements of electrodes were done in accordance with Surface Electromyography for the Non-invasive Assessment of Muscles (SENIAM) guidelines. Prior to electrode placement the skin was shaved, abraded and cleaned with alcohol to reduce signal impedance. Three electrodes were placed in vastus lateralis and three elcetrodes in vastus medialis of muscle. The contraction of muscle was monitored by researcher. Participant was required to hold each contraction for 10 seconds, rest 20 seconds in between contraction for five repetitions. In this study the participants performed seven exercises to the lower limb aided by isometric EMG training. These exercises are –

1. Quadriceps isometric contraction,

2. Hip adduction isometric,

3. Four ways straight leg raise and

4. 45 º knee extension.

The duration of the interventions were approximately 25 – 30 minutes/day, 2 days/week for 5 weeks. After the completion of the 5 weeks of intervention i.e. at the end of 10th week, a post intervention evaluation was done following baseline assessment protocol with maintaining standard procedure except for the anthropometric measurement. After the post intervention assessment the participants were requested not to attend the training session for the next 8 weeks. The participants were instructed to continue the activities of daily living and were advised not to participate in any form of training or exercises during the follow up period. They were also instructed not to have any changes in their lifestyle during the follow up period. Intermittent enquiries were done to ensure this. A follow up evaluation was done at 14th (follow-up phase I assessment) and 18th week (follow-up phase II assessment) respectively. All the measurements were done in line with the baseline measurement protocol with maintaining standard procedure as it was done at the beginning of the study. Once the data was collected from all the 45 participants after 18 weeks; it was analyzed statistically to determine the differences in the parameters at various stages of measurements. These differences were compared across the groups to determine the efficacy of the interventions and its superiority over the other. The data were treated with SPSS version 22.0. Descriptive statistics and repeated measures ANOVA, within and between interactions was done to compute the results of the study following analysis.

RESULTS:

The number of participants inlcuded in th final analysis were 45 due to drop out of 9 subjects at various phases of the study. Table 1 presents the demographic data of the participants of the study. It could be observed that females constituted the maximum number of the participants.Only 4 participants were observed to be of normal BMI whereas the other 41 subjects were on the overweight and obese category.Table 2 depicts the mean difference in average peak torque across various interventions and phases. I t could be seen that the average peak torque of the knee extensors improved across all the intervention groups. The normality of the data was established by kolomogrov-Smirnovtest. Mauchly’s test of Sphericity was done to evaluate the variances of difference among the groups followed by Greenhouse Geisser correctionsdue to the violation of the sphericity. Table 3 shows the comparison of the average peak torque with each treatment group based on time.Repeated measures ANOVA within group analysis was appplied followed by pairwise comparison with 95% confidence interval adjustment by Bonferroni correction. The results show that there were significant differences in conventional physiotherapy and isokinetic training group at all intervals of measurement (p<0.05) whereas in the EMG biofeedback group the difference was significant only between pre- post and pre-follow up 2 (p<0.05). The results of the intervention effect (Table 4) after repeated measures anova analysis followed by post hoc multiple comparisons using Bonferroni correction depicts that Isokinetic training was significantly better than conventional physiotherapy and EMG biofeedback (p<0.05). Pairwise comparison of group analysis with regard time (Table 5) highlights the difference in the average peak torque values across the intervention groups. It is evident that the isokinetic group was superior to other interventions across all the measurement levels (p<0.05).

Table 1.

	conventional physiotherapy	isokinetic training	emg biofeedback training
GENDER
Male	3	3	4
Female	11	12	12
Age(years)	56.57±3.67	53.67±2.63	56.00±3.52
Weight(kg)	62±6.39	69.53±5.77	71.94±9.53
Height(cm)	153.14±5.13	151.80±3.10	155.25±5.70
BMI(kg/m²)
Normal	3	1	0
Overweight	11	6	9
Obese	0	8	7

Table 2. Mean differences in average peak torque(Nm)

	Groups	Number of Measurements	180 degree extension
	Groups	Number of Measurements	Mean	SD
Average Peak Torque	CP	Pre	7.64	2.76
		Mid	13.75	7.71
		Post	19.93	14.44
		Fu1	19.31	13.69
		Fu 2	18.66	13.12
	ISO	Pre	12.21	5.89
		Mid	19.53	10.43
		Post	31.77	15.69
		Fu1	31.11	14.91
		Fu 2	30.82	14.56
	EMG BIOFEEDBACK	Pre	10.63	6.28
		Mid	11.89	4.93
		Post	16.91	8.95
		Fu1	16.39	9.53
		Fu 2	18.65	9.96

Figure 2.Mean differences in strength of quadriceps across various intervention groups

Table 4. Overall mean differences of strength among three intervention groups (Intervention effect)

Comparison	Mean difference (95%ci)	Sig.^b
Conventional Physiotherapy -Isokinetic Training	-9.233(-18.151,-.316)	.040*
Conventional Physiotherapy -Electromyography Biofeedback	.962(-7.820,9.744)	1.000
Isokinetic Training -Electromyography Biofeedback	10.195(1.571,18.820)	.016*

Table 5. Comparison of the average peak torque among three different treatment groups based on time (Time-treatment interaction)

	COMPARISON	Mean Difference (95%CI)	Sig.^B
	COMPARISON	Mean Difference (95%CI)	Sig.^B
Pre	Conventional Physiotherapy -Isokinetic Training	-4.578(-9.479,.323)	.074
	Conventional Physiotherapy- Electromyography Biofeedback	-2.996(-7.822,1.831)	.388
	Isokinetic Training-Electromyography Biofeedback	1.582-(3.158,6.322)	1.000
Mid	Conventional Physiotherapy -Isokinetic Training	-5.777(-13.153,1.600)	.173
	Conventional Physiotherapy- Electromyography Biofeedback	1.856(-5.408,9.121)	1.000
	Isokinetic Training-Electromyography Biofeedback	7.633(.499,14.767)	.032*
Post	Conventional Physiotherapy -Isokinetic Training	-11.845(-24.111,.421)	.062
	Conventional Physiotherapy- Electromyography Biofeedback	3.022(-9.057,15.102)	1.000
	Isokinetic Training-Electromyography Biofeedback	14.867(3.004,26.730)	.010*
Follow up 1	Conventional Physiotherapy -Isokinetic Training	-11.806(-23.694,.081)	.052
	Conventional Physiotherapy- Electromyography Biofeedback	2.920(-8.787,14.626)	1.000
	Isokinetic Training-Electromyography Biofeedback	14.726(3.229,26.223)	.008*
Follow up 2	Conventional Physiotherapy -Isokinetic Training	-12.162(-23.861,-.463)	.039*
	Conventional Physiotherapy- Electromyography Biofeedback	.007(-11.514,11.528)	1.000
	Isokinetic Training-Electromyography Biofeedback	12.169(.855,23.484)	.031*

DISCUSSION:

Muscle strength is a very important component in the biomechanics of the knee joint. Deterioration of muscle strength can lead to atypical joint biomechanics. This abnormality in joint biomechanics may in turn lead to destruction of the articular cartilage and irregular distribution of forces across the knee joint. While normal distribution of forces in any joint gets impaired, that may lead to imbalance of the muscle across the joint, and thereby causing further worsening of the knee joint structure. Muscle strength can be measured in many ways employing differential methods and techniques. One way of measuring muscle strength of the knee joint is by measuring the average peak torque of the extensor muscle and the flexor muscle at different velocities. In the present study, the researcher recorded the average peak torque values to measure the strength of the muscle in participants with osteoarthritis of knee. The average peak torque could be most authentically assessed by using Biodex 4 Isokinetic dynamometer at differential velocities. In the current study, the researcher measured the average peak torque at velocity of 180 degree per second due to the reason that measurement of peak torque at lower velocities may increase the friction in the joints and perhaps may cause worsening of the already damaged knee joint.The findings of the average peak torque at 180º/second extension overall gave an impression that marked improvement in peak torque was evident across different phases of assessment, which was observed amongst all of intervention groups. The participants of Isokinetic Training group were observed to have better improvement in the peak torque values compared to that of the EMG Biofeedback training group (p< .05). In the post intervention assessment, the Isokinetic Training group had achieved better peak torque compared to the Conventional Physiotherapy group participants (p< .01). It could also be observed that the participants of the isokinetic training group had significantly better peak torque values compared with that of the counterparts of the EMG Biofeedback training group (p< .01). The same trend of improvement continued in the follow up phases too, i.e. at the end of 4th and 8th week, after the cessation of the intervention. This finding of improvement could be partially attributed to the Isokinetic Training introduced in the current study. This finding however gets support from those observed by Huang and his co-researchers (2005)^[10] and Gur and

colleagues (2002)^[33] as well. Huang et al., (2005)^[10] reported an increase in the average peak torque of the muscle at 180°/second extension in the group that underwent isokinetic training (M =23.5, SD=10.5). Similarly Gur et al., (2002)^[33] observed an average of 30 % increase in the average peak torque values at 180°/second extension activity. In the current study the participants in the isokinetic training group were also observed to have an increased average peak torque (M =30.82, SD=14.56). In the current study we could observe that the average peak torque of the muscle improved with 20 training sessions whereas in the research conducted by Huang et al., (2005)^[10] it could be observed that an increased average peak torque was recorded at the end of 24 sessions. It is also worthy to be noted that the training session was 2 sessions per week in the current study whereas in the previous researches it was 3 sessions per week. This could highlight the fact that 2 sessions per week of isokinetic training could help in improvement of average peak torque of the extensor muscle of the knee in osteoarthritic patient. It could also be stated that isokinetic training proved to improve the strength of the muscle better compared with that of EMG Biofeedback training group in the post intervention assessment. This could be due to the fact that the type of muscular contraction observed with these training. The EMG Biofeedback training group was mainly an isometric contraction compared to that of isokinetic training which was of a concentric and eccentric contraction of the muscle. Static or isometric contraction is a contraction that cannot be held for a long time due to development of fatigue. Hence, the possible reason for the marked improvement in the muscular strength, as expressed in terms of average peak torque, could be assumed as due to the accumulated impact velocity-dependent loading of the muscle, incurred during the Isokinetic Training. Anwer and his research associates (2011)^[19] conducted a randomised controlled trial to find out the effectiveness of EMG aided training along with isometric quadriceps exercise on participants with osteoarthritis of knee. They recruited about 33 participants (10 men and 23 women) and applied EMG aided training along with isometric quadriceps exercise for a group (n=17) and the control group received only exercise program (n=16). Only 15 participants in each group were followed up and analysed. The intervention consisted of EMG aided training guided isometric exercise for the experimental group and isometric exercise along with sham EMG aided training (placebo) for the control group. Both the groups were administered hydrocollator packs for 20 minutes. The intervention was imparted 5 days a week for 5 weeks. At the end of the fifth week Anwer et al., (2011)^[19]reported a significant improvement in the quadriceps strength in the EMG aided training group. The findings of our study also highlighted that the EMG biofeedback training was also effective in improving the strength of the quadriceps muscle. Whereas Yilmaz and co-researchers (2010)^[18] reported no significant difference in outcomes between regular strengthening exercises and EMG aided training guided exercises.Ozdincler et al., (2005)^[38] investigated the effects between progressive resisted exercise and closed kinetic chain exercise on participants (N=30) with osteoarthritis of knee. The participants in one group underwent progressive resisted exercises using DeLorme„s technique, while the participants in other group underwent closed kinetic chain exercises for 5 weeks. At the end of the study the researcher and his colleagues reported that both groups had significant improvements in muscle strength and reduction in pain. They also reported that closed kinetic chain exercises increases the muscles strength and functional performance of participants with osteoarthritis of knee.Our study also indicate that the physiotherapy training improved the strength of the knee exensor muscle which was in accordance with the finding of Ozdincler et al., (2005)^[37].

Limitations:

Our study has few limitations such as smaller sample size,more female participants,participants recruited mainly from one hospital,non inclusion of other grades of knee osteoarthritis and absence of no treatment control group.These shortcomings should be considered for future researches.

CONCLUSION:

Our study indicates that all the interventions namely conventional physiotherapy,isokinetic training and EMG biofeedback were effective in improving the strength of the knee extensor muscle. But when a comparison was made amongst them isokinetic training evidentially proved to be superior in enhancing the strength of the muscle quadriceps femoris in patients with osteoarthritis of knee.

Conflict of interest:

Declared none

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Received on 18.04.2018 Modified on 04.05.2018

Research J. Pharm. and Tech 2018; 11(6): 2517-2524.

DOI: 10.5958/0974-360X.2018.00465.1

Comparison	Conventional physiotherapy		Isokinetic Training		EMG Biofeedback
	MD (95%CI)	Sig.^b	MD (95%CI)	Sig.^b	MD (95%CI)	Sig.^b
Pre-Mid	-6.114(-11.872,-.356)	.034^*	-7.313(-12.829, -1.798)	.006^*	-1.263(-5.309,2.784)	1.000
Pre-Post	-12.293(-23.690,-.896)	.030^*	-19.560(-29.892, -9.228)	.000^*	-6.275(-12.444,-.106)	.045^*
Pre-FU 1	-11.671(-22.433,-.910)	.029^*	-18.900(-28.791,-9.009)	.000^*	-5.756(-12.988,1.476)	.195
Pre-FU 2	-11.021(-21.258,-.785)	.030^*	-18.606(-27.975,-9.237)	.000^*	-8.019(-15.475,-.562)	.030^*