Comparison of active release and post-isometric relaxation techniques on functional performance in patients with chronic lateral epicondylitis

INTRODUCTION

Lateral epicondylitis (LE) is the most prevalent reason for lateral elbow discomfort in older adults. It is also known as “tennis elbow.” It is an overuse injury at the point of beginning of the extensor carpi radialis brevis (ECRB) tendon caused by eccentric overload of the common extensors.^[1] A new term, “tendinosis or tendinopathy,” has become popular and is now commonly used compared to the previous one, “tendinitis,” due to repetitive strain and chronic degeneration of the forearm’s common tendons of extension attached to the lateral epicondyle of the humerus.^[2,3] Maffulli et al. were among the earliest researchers to advocate for a shift in medical terminology from tendinitis to tendinopathy. At present, tendinopathy is a recognized term that refers to a number of tissue diseases that develop in damaged tendons and represents non-rupture injury to the tendon or para-tendon that worsens under mechanical strain.^[4] The terminology shift is being linked to new advancements in comprehension of tendon pathophysiology, indicating a greater clarity of the excessive use cycle and the subsequent structural as well as functional harm in tendons with chronic pain; more information regarding the mechanical stability disturbances that cause chronic tendon disease pathology; and an improved comprehension of the crucial role of both internal and external lifestyle factors.^[5]

The ECRB muscle is more prone to injury when the tendon is stretched over the radial head, resulting in an increase in tensile load during repetitive wrist extension. It leads to further strain of the tendon during the forearm supination. This is due to the radial head’s anterior rotation against the ECRB muscle.^[3] LE is one of the most commonly work-related disorders.^[6] The prevalence of LE is more common among the middle-aged general population. In the general population, the prevalence of LE among males lies approximately between 1.0 and 1.3% and among females between 1.1 and 4.0% per year per 100 subjects.^[6]

The pathophysiology of LE shows abnormal arrangements of collagen fibers, vascular disruption, and cellular disorganization at tendon fibers that lead to tendinosis. Musculoskeletal ultrasound examination reveals increased calcification, increase in heterogeneity, and thickening observed in common extensor tendons and marked irregularity of lateral epicondyle.^[7,8] Subjects with LE are unable to perform normal functional tasks such as holding and gripping activities. LE patient presents with pain and local tenderness along and distal to the lateral epicondyle of the elbow joint and limited functional activities. The pain is observed due to repetitive wrist flexion and extension of the wrist and repetitive supination and pronation are associated with decreased grip strength. Some sleeping positions can be provocative and cause pain, such as the overhead arm position, mostly when lying on the side. The nightly overhead sleeping position presents with severe morning pain and delayed tendon healing at the initial acute lesion of the lateral epicondyle of the elbow, called the “pathological sleep position.”^[9] The physical examination provides an early diagnosis of LE and helps to identify a differential diagnosis. On palpation, 1–2 cm distal to the lateral epicondyle, a spot of maximal pain, and tenderness is located. The special tests used to confirm the diagnosis of LE act as pain provocation tests. Three specific tests were used: Mill’s and Cozen’s test and Maudsley’s (3^rd finger resisted extension).^[10,11]

Post-isometric relaxation (PIR) is a type of muscle energy technique (MET) used to reduce muscle tone and lengthen and relax the shortened and hypertonic agonist muscles against the isometric contraction. This happens due to the activation of a naturally neurological protective mechanism through the stretch receptors “Golgi tendon organs,” located in the muscles’ tendon. About 75% of the maximal isometric contraction of a patient is maintained against a practitioner’s resistance for 5 s, followed by the release of resistance until a new range gain with another barrier is again met. The whole procedure should be repeated 3–5 times during each treatment session.^[12]

Active release technique (ART) is a non-invasive, soft-tissue rehabilitation approach that removes and breaks adhesions and scar tissue formation, which can lead to pain, swelling, stiffness, and altered sensations due to mechanical dysfunctions within soft tissues. ART combines the exertion of deep tissue pressure on the tender region of concern with active patient engagement to shift tissue from a shorter to an extended posture to prevent the development of adhesions. It is also used to release nerve entrapment within muscles, tendons, and adjacent fascia. It contains four steps: (a) Tissue tension, (b) tissue texture, (c) tissue movement, and (d) tissue function.^[13]

Therefore, this study aimed to assess the comparative effects of PIR and ART on pain inhibition, grip strength, and functional ability among individuals suffering from chronic LE. The results of this study will help provide prompt assistance in selecting the most beneficial approach for this targeted population. Thus, rapid improvements can be attained with fewer therapy sessions and patient visits.

MATERIALS AND METHODS

A randomized clinical pilot study was conducted from November 2019 to March 2020. The trial was registered in the World Health Organization Registry of Iranian registry of clinical trials (IRCT), having reference no # IRCT20200502047274N1. Data was collected from Sialkot Medical Complex and Sardar Begum Hospital Sialkot. In this study, the sample size was 24. A total of 30 LE subjects were assessed for eligibility. Participants who were clinically diagnosed and referred by their physician or orthopedician with chronic LE were recruited.

Four patients were unable to meet the inclusion criteria. The age of the two participants was above 45, and two patients had pain greater than six on the Numerical Pain Rating Scale (NPRS). Two patients declined to participate and were excluded from the study. Participants attended an outpatient physiotherapy clinic after at least six weeks of symptoms and were evaluated with screening clinical special tests for chronic LE. Hence, a total of 24 individuals were recruited based on the criteria for inclusion and picked by the chit-pick box technique of simple randomization.

In this simple randomized single-blinded clinical pilot study, the outcome assessor was blinded regarding patients’ baseline characteristics, treatment protocol, and study population. The age group of patients was between 25 and 45 years. For subjects with unilateral elbow involvement, pain intensity levels were between 3 and 6 on 0–10 points of the NPRS; subjects with positive “Cozen’s test” or “Mill’s test” were examined as LE, and subjects’ willingness to participate in this study. Before commencing the treatment regimen, participants were given written consent, and the procedure to be followed was explained to them.

Participants were excluded if they had a history of cervical radiculopathy, peripheral nerve involvement signs and symptoms, any previous surgery of the elbow, a history of previous physiotherapy treatment, and any steroid injection during the past six months.

All participants were allocated into two equal groups: Group A (ultrasound therapy with ART) and Group B (ultrasound therapy with PIR technique).

Each treatment protocol consisted of three sessions per week on alternate days. A total of 12 sessions per four weeks on alternate days were given. Assessment tools were the patient-rated tennis elbow evaluation (PRTEE) scale, NPRS scale, and handheld dynamometer used to collect before the first treatment session (pre-treatment) and the 12^th treatment session (post-treatment). The evaluation form consists of general demographic data, duration of symptoms, detailed examination of the elbow joint, PRTEE scale to assess functional performance, NPRS scale for level of pain assessment, and handheld dynamometer for measuring the strength of gripping.

Outcome measures

The primary outcome measures were NPRS, hand grip strength with a handheld dynamometer, and PRTEE, which were taken before interventions as pre-treatment values and after four weeks as post-treatment values. The CONSORT flow diagram is shown in Figure 1.

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Figure 1:

Consolidated standards of reporting trials flow diagram. ART: Active release technique, PIR: Post isometric relaxation, n: total number of participants

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RESULTS

The groups were similar according to their demographic variables, as shown in Table 1. In both groups (A and B), the mean age of participants was 35–38 years, and it is shown in Figure 2. An independent t-sample test was applied for across the group comparison. Results were statistically significant between the two groups for NPRS and PRTEE with P < 0.05, as shown in Table 2. The results were insignificant for grip strength, and P-value exceeded 0.05.

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Figure 2:

Age of participants.

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The NPRS scale, grip strength, and PRTEE scale within each experimental group employing a paired-t-test are compared in Table 3. A statistically significant disparity was observed in both groups pre- and post-intervention.

DISCUSSION

The findings of a recent study showed that both the ART (Group A) and PIR technique (Group B) showed significant improvements in hand gripping strength and functional performance and reduced pain associated with chronic LE following four weeks of treatment sessions. The reported effectiveness of the PIR technique compared to other interventional techniques is supported by published previous literature.^[14] Females are more affected by chronic LE than males.^[15] Dominant arms of right-sided patients are more commonly affected by LE as compared to left-sided. The number of patients lies within 40–45 years of age.^[16]

The present study revealed that males were more affected by LE in both groups. Dominant right-sided were more affected, but left-sided patients were also affected almost similarly. The mean age of patients was in the middle age group of 35–38 years.

The present study found statistically noteworthy outcomes across ART and PIR procedure groups regarding NPRS, strength, and PRTEE scales using paired sample t-tests. However, the mean change in values of the PIR group improved more than that of the other treatment group. This result is similar to a previous study, which shows the difference in improvement in the PIR group as compared to the ART group based on pain threshold (NPRS), grip strength, and functional performance duration by the PRTEE scale.^[15]

In most of the previous literature, VAS was used as an outcome measuring tool for evaluating the pain threshold level by applying METs and, compared to other related techniques such as MWM follow-up of 3 weeks.^[3] The recent study revealed that the NPRS scale was used to assess pain using ART and PIR techniques as a measuring tool, followed by four weeks of interventions. Regarding inter-group comparison, pain-free grip strength improved significantly with the ART after the application of 12 sessions over four weeks (P < 0.05). ^[3] The present study showed that grip strength measured by handheld dynamometer showed that both groups had similar results (P > 0.05) followed by 12 sessions of four weeks. There was a significant decrease in mean from 4.50 to 2.66 (P < 0.05) on the NPRS scale in both group analyses.^[17] The results are similar to the present study, decreasing from 3.10 to 0.37 (P < 0.05) on the NPRS scale in both group analyses. The consequences of the present study showed that ART and PIR techniques have statistically significant differences in the post-treatment value of NPRS score between group analyses (P < 0.05) and for both group analyses (P < 0.001).

The PRTEE scores improved significantly by ART after the application of 12 sessions of four weeks (P < 0.05).^[18] The present study showed that PRTEE scores, although improved by ART, but more significantly improved by PIR (P < 0.05) as compared to the ART (P > 0.05), followed by 12 sessions of four weeks. Kaux et al. recommended that PRTEE is the best scale for evaluating pain, functional performance in LE-affected patients, and improvement in ADLS following post-intervention programs.^[19] This evidence supported the present study that the PRTEE scale evaluated and significantly improved after applying ART and PIR techniques.

This study speculates that both interventions can be effective in a clinical setup with or without conventional treatment protocol for long-term and better improvements. However, the PIR technique is more effective because it directly corrects muscle imbalance than ART.

CONCLUSION

Both the ART and PIR methods were effective, but the PIR techniques, along with conventional therapy, were found to be much better than the ART group for reducing pain on a NPRS, improving grip strength by a handheld dynamometer and patient-rated LE evaluation questionnaire with a marked increase in functional performance of normal ADLS after 12 treatment sessions. The results were statistically significant for Group B in terms of mentioned outcome measures based on mean differences.