Comparative study to evaluate efficacy of prolotherapy using 25% dextrose and local corticosteroid injection in tennis elbow – A prospective study

Abstract

Introduction:

Tennis elbow is a common painful condition with a prevalence rate of 1–3%. The condition starts as a micro-tear in extensor carpi radialis brevis and its degeneration because of repetitive overload. Conservative measures are undertaken initially because symptoms in most patients improve with time and rest. Adjunctive treatment includes steroid injection, autologous plasma, exercise, and prolotherapy. Dextrose prolotherapy by virtue of its multi-modal mechanism of action has emerged as a cost-effective treatment option for chronic musculoskeletal and arthritic pain.

Materials and Methods:

A total of 260 patients were included in the study and divided in two groups for administration of steroids or dextrose prolotherapy. The Visual Analog Scale (VAS) and Mayo Elbow Performance Scale (MEPS) scores were taken for patients at regular follow-up.

Results:

All patients showed improvement in VAS score and MEPS score following dextrose prolotherapy as well as patients injected with steroids.

Conclusion:

Both prolotherapy and steroid injection offer adequate pain relief and functional outcome, although prolotherapy has been shown to be superior and given long-lasting results compared to steroid injection in management of tennis elbow.

Introduction

Tennis elbow is one of the most common elbow conditions with a prevalence rate of 1–3%.[1] The peak incidence is reported at 40–50 years of age, and in middle-aged females, its incidence increases to 10%.[2] In 1883, the term “Lawn-tennis elbow” was coined.[3] RP Nirschl et al. coined the term “Angio fibroblastic tendinosis” as inflammatory cells are not found in the tendon tissues.[4,5]

The condition starts as a micro-tear in extensor carpi radialis brevis and its degeneration because of repetitive overload. It is believed to be an over-use injury secondary to an eccentric overload of the common extensor tendon at the origin of the extensor carpi radialis brevis tendon. Tennis elbow primarily results from the repetitive strain caused by activities that involve loaded and repeated gripping and/or wrist extension. It is common in individuals who play tennis, squash, badminton, or any activity involving repetitive wrist extension, radial deviation, and/or forearm supination.[6,7] More recently, postero-lateral micro-instability has been suggested as a possible etiology.[8] Acute symptoms occur in young patients, whereas chronic, recalcitrant symptoms occur in older patients.[9] Most of the patients show improvement with conservative measures, but it is time-taking.[10] Non-operative treatment includes rest, brace, non-steroidal anti-inflammatory drugs, rehabilitative resistance exercise with progression of the exercise program, corticosteroid injection, autologous blood injection, prolotherapy using 25% dextrose, extracorporeal shock wave therapy, botulinum toxin injection, and hyaluronic acid with chondroitin sulfate injection. Patients who fail to respond to conservative measures are considered for surgical treatment. Various surgical options available are open common extensor origin release, partial excision of extensor origin with repair, Z lengthening of the extensor carpi radialis brevis, excision of the proximal part of the annular ligament, excision of the synovial fringe of the radio-humeral joint, bursectomy, percutaneous release of the common extensor origin, a combination of the aforementioned procedures, and an arthroscopic release.[11]

Prolotherapy has emerged as a cost-effective treatment option for chronic musculoskeletal and arthritic pain. It involves the injection of a small amount of solution into multiple painful ligament/tendon insertions, typical trigger points, as well as into the adjacent joint spaces to induce healing of the injured structures. The injected solution causes a healing process that is similar to the body’s natural healing process, whereby a local inflammatory cascade is initiated, which triggers the release of growth factors and collagen deposition.[12]

Dextrose prolotherapy is presumed to work by several mechanisms including a direct effect, an osmotic effect, and an inflammatory growth effect. Dextrose injections below a 10% solution directly stimulate proliferation of cells and tissues without causing a histological inflammatory reaction. When dextrose is injected in greater than 10% solution, it is presumed to be causing an osmotic (concentrated) gradient outside of the cells where it is injected. This causes some cells to lose water and lyse with the net effect being an influx of growth factors and inflammatory cells that initiates the wound-healing cascade to that specific area. Dextrose is an ideal agent because it is water-soluble and a normal component of blood chemistry, which can be injected safely into multiple areas and in large quantity. The presumed net result is the deposition of new collagen into injured structures, such as ligaments and tendons.[13]

Steroids exhibit anti-inflammatory action. They inhibit fibroblast proliferation, angiogenesis, and formation of granulation tissues. They also interfere with collagen precursor ground substance formation and collagen repair. Signs of inflammation such as hyperemia and tendon thickness have reported to be minimized by its use.[14] However, the lack of inflammatory markers in LE by histopathological studies makes the concept of inflammation less acceptable.[15] Its degenerative picture is increasingly accepted because researchers demonstrated angiofibroblastic changes in the examined specimens obtained from LE patients at the surgery time. Nevertheless, it could plausibly be argued that because histopathological studies involve recalcitrant cases of LE, the documented histological features represent the end stage of a process that commences with an early phase of inflammation, and samples could pathologically be dominated by chronic degenerative changes. Others explain the analgesic actions of steroids by the effects on the calcitonin gene-related peptide, neuropeptides, and substance P, which are increased in tendinopathy.[16]

Elbow pain with a diagnosis of tennis elbow is frequently encountered by primary caregivers and family physicians. An updated knowledge about effective management of tennis elbow will be very helpful for primary caregivers in successfully treating this common elbow painful condition.

Aims and Objectives

To evaluate the efficacy of prolotherapy using local injection of 25% dextrose and local corticosteroid injection in tennis elbow.

Materials and Methods

We performed a prospective comparative study on tennis elbow patients presenting to our Orthopedics department (OPD) at our tertiary care center during December 2020 to December 2021. Two hundred and eighty-five patients of tennis elbow were reported during the period. The diagnosis was made clinically based on symptoms, point tenderness, and pain elicited by Cozen test. Patients clinically diagnosed to have tennis elbow and after excluding all other causes of elbow pain were subjected to ultrasonographic examination of the elbow to confirm the diagnosis of tennis elbow. Findings of hypoechoic signal from the extensor tendons suggestive of edema of the extensor tendons further supported the clinical diagnosis. Ethical approval was obtained by Institutional Ethics Committee, RIMS, Ranchi memo number -122 IEC dated 23/11/2020.

Among these, 260 patients met our inclusion criteria of an age between 18 and 60 years and consented to being part of the study. A total of 25 patients were excluded (five patients had received previous treatment in the form of local injections, eight patients were suffering from symptoms of pain around the elbow because of other reasons such as inflammatory arthropathies, posterior interosseous nerve syndrome, osteochondritis dissecans of the elbow, and elbow pain referred from the cervical spine/ipsilateral shoulder, and 12 had uncontrolled diabetes mellitus.

The eligible patients were divided into two categories based on lottery. The first group of patients were given prolotherapy with 25% dextrose (group A), and the second group were given local corticosteroid triamcinolone (group B). One milliliter of the drug was given to every patient. The site of injection was 5 mm distal to the lateral epicondyle in the extensor tendons, particularly the extensor carpi radialis brevis tendon. The skin was painted with povidone-iodine and ethyl alcohol. One milliliter of 2% lignocaine with adrenaline was injected at the injection site after giving the test dose. After 10 min, the proposed injection was injected. The injection was given on and around the tendon and not inside the tendon. If any resistance was felt during the injection, the needle was withdrawn a bit and again injected. Patients were advised regarding post-injection pain that was managed with paracetamol. Patients were advised for rest during initial 2 weeks in the form of refraining from strenuous activities by the extremity under study after the injection.

Patients were followed up in OPD at regular intervals, and outcome measures were monitored using Visual Analog Scale (VAS) and Mayo Elbow Performance Scale (MEPS). Scores were assessed and documented before injection and post injection at 6 weeks, 12 weeks, 24 weeks, and 1 year.

Data were tabulated and analyzed. Descriptive analysis was used for the numeric data. Two-sample t-test was used to compare VAS scores and MEPS scores in patients treated with 25% dextrose with those that were treated with injection triamcinolone. A P value less than 0.05 was considered statistically significant.

Results

In this study of total 260 patients, 130 patients received prolotherapy using 25% dextrose; the mean initial age of presentation for this group was 43.88 years, and the rest 130 patients had received injection triamcinolone with the mean age being 44.14 years. Among all patients, 102 were males (39%) and 158 patients were females (61%). Out of 260 patients in the study, 44 patients had diabetes mellitus (17%), 67 patients had hypertension (25.7%), 19 patients suffered from gout (7.3%), 32 patients had hypothyroidism (12.3%), and 98 patients suffered from no co-morbidity (37.7%). Of all the patients, 85 patients had left elbow affection (32.7%), 170 had right-sided elbow affection (65.3%), and only five had bilateral elbow affection (2%). Of the total affections, 85 elbow were non-dominant (32.7%) and 175 were dominant (67.3%). However, correlation among the variables (paired t-test was used) between dominant and non-dominant elbows showed statistically insignificant values in both VAS scores and MEPS scores [Table 1]. The mean duration of symptoms at the time of the first presentation to OPD was 4.4 months. Demographical variables (age, sex, co-morbidity status) had a statistically insignificant impact on both VAS scores and MEPS scores.

Table 1.

VAS score comparision in dominant and non-dominant limb in both groups

	Variable	Dominant		Non-Dominant		P
		n	Mean±S.D	n	Mean±S.D
Patients treated with 25% dextrose	Pre-injection	93	68.84±1.31	37	68.64±0.85	<0.195
	At 6 weeks	93	52.31±1.25	37	52.43±0.86	<0.70
	At 12 weeks	93	43.16±3.30	37	44.24±2.74	<0.95
	At 24 weeks	93	32.43±2.46	37	33.37±2.11	<0.97
Patients treated with inj. triamcinolone	At 1 year	93	21.75±2.29	37	22.08±2.09	<0.77
	Pre-injection	84	67.45±2.94	46	66.71±2.79	<0.08
	At 6 weeks	84	49.13±1.63	46	49.08±1.60	<0.43
	At 12 weeks	84	40.37±2.75	46	41.08±2.73	<0.91
	At 24 weeks	84	31.97±2.60	46	32.13±2.17	<0.63
	At 1 year	84	26.80±2.81	46	27.32±2.11	<0.86
MEPS score comparision
	Variable	Dominant		Non-Dominant		P
		n	Mean±S.D	n	Mean±S.D
Patients treated with 25% dextrose	Pre-injection	93	66.50±3.02	37	67.83±2.51	<0.99
	At 6 weeks	93	76.72±2.49	37	77.83±2.51	<0.98
	At 12 weeks	93	83.81±2.13	37	84.59±1.38	<0.97
	At 24 weeks	93	90.96±2.11	37	90.81±1.86	<0.34
Patients treated with inj. triamcinolone	At 1 year	93	97.95±2.47	37	98.78±2.17	<0.96
	Pre-injection	84	59.26±1.94	46	59.34±2.26	<0.58
	At 6 weeks	84	73.47±2.31	46	72.71±2.51	<0.04
	At 12 weeks	84	81.82±2.54	46	81.84±2.44	<0.51
	At 24 weeks	84	87.74±3.86	46	88.04±4.14	<0.65
	At 1 year	84	91.52±2.44	46	92.39±2.52	<0.97

VAS scoring performed at pre-injection, 6 weeks, 12 weeks, 24 weeks, and 1 year showed improvement in scores for both groups of patients, that is, those receiving injection 25% dextrose and those receiving injection triamcinolone, but on comparison of scores using paired t-test, patients receiving 25% dextrose had greater improvement of scores at 6 weeks, 12 weeks, and 24 weeks, and it was statistically significant [Table 2]. However, at 1 year, it was insignificant.

Table 2.

Comparison of VAS score between patients treated with 25% dextrose and triamcinolone

Variable	VAS Score for patients treated with 25% dextrose		VAS Score for patients treated with Inj. Triamcinolone		P
	n	Mean+/-S.D.	n	Mean+/-S.D.
Pre-injection	130	68.79±1.19	130	67.16±2.89	<0.00
At 6 weeks	130	52.34±1.15	130	49.13±1.63	<0.00
At 12 weeks	130	43.46±3.18	130	40.68±2.77	<0.00
At 24 weeks	130	32.70±2.40	130	32.06±2.45	<0.0175
At 1 year	130	21.84±2.23	130	27.02±2.58	<1.00

MEPS scores again showed much improved outcome in patients receiving prolotherapy with 25% dextrose as compared to triamcinolone inj. The scores were statistically significant at 6 weeks, 12 weeks, 24 weeks, and 1 year [Table 3]. MEPS scoring being a more comprehensive scoring also proved that 25% dextrose prolotherapy improved outcome in tennis elbow patients.

Table 3.

Comparison of MEPS score between patients treated with 25% dextrose and triamcinolone

Variable	MEPS Score for patients treated with 25% dextrose		MEPS Score for patients treated with Inj. Triamcinolone		P
	n	Mean+/-S.D.	n	Mean+/-S.D.
Pre-injection	130	66.88±2.93	130	59.26±2.07	<0.00
At 6 weeks	130	77.03±2.54	130	73.15±2.42	<0.00
At 12 weeks	130	84.03±1.97	130	81.80±2.49	<0.00
At 24 weeks	130	90.92±2.04	130	87.80±3.93	<0.00
At 1 year	130	98.19±2.41	130	91.84±2.50	<0.00

Discussion

This prospective study indicates that both injection triamcinolone and prolotherapy using 25% dextrose are effective in reduction of pain and improvement in functional outcome in patients with tennis elbow [Table 1].

According to Krogh et al.,[17] for patients undergoing dextrose prolotherapy, improvement lasted even after the first follow-up and the results after one injection were still encouraging; however, in those who were injected with steroids, only a short-term improvement was seen. They concluded that both methods were proven to be effective in the short-term treatment of chronic lateral epicondylitis, but dextrose prolotherapy seems to be slightly more efficacious than steroid injection over a longer period. This finding has also been in elucidated in our study where improvements in VAS and MEPS scores were seen more in patients treated with dextrose prolotherapy as compared to steroids [Tables 2 and 3], indicating significant final outcome in the prolotherapy group.

Studies performed by Boonstra et al.[18] show that reliability of VAS as compared to MEPS is less. MEPS score is more specific with regard to improvement in functional outcome [Table 2], where MEPS shows a statistically significant difference in patients treated with prolotherapy even in final follow-up, which is not shown when patients are assessed for VAS score [Table 3]. This above statement has been further impressed upon [Figures 1 and 2].

Figure 1.

Representation of improvement of MEPS scores following dextrose prolotherapy versus steroids

Figure 2.

Representation of reduction of VAS scores following dextrose prolotherapy versus steroids

Scarpone et al.[19] observed for efficacy of prolotherapy using 11% dextrose. The study showed improvement in pain and increased isometric strength scores compared to the normal saline control group.[3] This improvement was maintained at long-term follow-up. In our study, we have used 25% dextrose. Our study shows improvement in both the prolotherapy and triamcinolone groups at initial follow-ups. However, prolotherapy proved to have significantly better and longer effects.

Our findings have been consistent with the previous studies, and we have given only single injection.

Tennis elbow is a common painful elbow condition which can be diagnosed easily and can be treated easily with limited resources. However, its diagnosis can be easily missed also. Primary caregivers and family physicians commonly encounter tennis elbow in their day-to-day practice. This condition can be easily treated without any need of much resources in out-patient basis. Local injection (prolotherapy) using steroids or 25% dextrose helps in treating this painful condition effectively; however, 25% dextrose gives long-lasting results. The injection technique is also simple. This article will help primary caregivers and family physicians in treating tennis elbow effectively.

Limitations

Sample size is a limitation of this progressive study. Age-matched individuals with similar pre-injection scores in both groups could have been compared for better evaluation of results.

In future, age- and gender-matched individuals with similar co-morbidities can be undertaken to further impress upon the results.

Conclusion

Our study shows that there is improvement in functional outcome of patients in the prolotherapy and steroid injection groups during early follow-ups. However, in the prolotherapy group, this improvement persisted for a longer time frame as compared to patients treated with steroids. To conclude, prolotherapy using dextrose had better functional outcome and longer effects in management of tennis elbow.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.