Pain from the lateral aspect of the elbow was first described in 1873, and has since then been given different names such as tennis elbow (TE), lateral epicondylitis, epicondylosis, epicondylalgia and lateral elbow pain. The most frequently used term is probably TE, implying a relationship with repetitive mechanical load while using a forceful grip, as in playing tennis [1] 

The Lateral Epicondylitis was first introduced by Runge in 1873 as “writer’s cramp”. The official taxonomy of the “Lateral epicondylitis”s term was declared in 1883 by H. P. Majors in the article of The British Journal of the Sports Medicine titled as “Lawn Tennis Elbow”[2]. 

Lateral epicondylitis is an inflammatory condition that occurs at the origin of the common extensor tendon of forearm over the lateral epicondyle. It is the commonest chronic disabling painful condition of the elbow. It causes symptoms in 1% to 3% of the general population. It is common in people whose occupation requires frequent rotatory motion of the forearm like carpenter, gardener, computer workers and knitting workers. The age of onset of lateral epicondylitis is between 35 and 50 years with an equal male to female sex ratio. The dominant upper limb is most commonly affected [3].

The prevalence of TE is 1-2 %, and the condition is mainly seen among middle aged people [1,6,7,8,9]. TE causes pain and functional impairment, and many of the patients are unable to work during weeks, up to years, with a detrimental effect on productivity. Most patients will recover within a year [4]. 

Symptoms may include local tenderness over the lateral epicondyle, pain in the extensor muscles induced by gripping or resisted extension movements of the wrist. On examination, pain may be exacerbated by resisted wrist extension in the pronated position. It is worse with the elbow at full extension. The range of motion of the wrist and elbow is usually complete [3].

In the majority of cases, non-obvious underlying causes can be identified [1]. Extensor carpi radialis brevis (ECRB) is the most commonly affected muscle, but supinator and other wrist extensors such as extensor carpi radialis longus, extensor digitorum, extensor digiti minimi and extensor carpi ulnaris can be involved. Any activity involving excessive and repetitive use of these muscles (for example tennis, playing an instrument, typing, manual work) may cause the tendinosis[5]. Smoking and obesity have been identified as significant risk factors[1]. 

Clinically, tennis elbow usually presents insidiously with point tenderness over the lateral epicondyle, with pain frequently radiating into the proximal forearm. The symptoms can usually be reproduced with resisted wrist extension, while the elbow is extended[6]; or with resisted extension of the middle finger at the metacarpophalangeal joint, while the elbow is extended and forearm pronated (Maudsley's test) [7]. A very specific test is the back of the chair pick up test, which involves gripping and lifting an object (such as the back rest of a chair), with the wrist flexed and ulnar deviated, the forearm pronated and the elbow flexed[8]. Grip strength has also often been found to be decreased on the affected side [9]. 

The initial treatment is with rest, modification of activity, local splints, and steroid injection, and 90% of patients respond to conservative treatment [10]. 

Those who do not respond to conservative treatment are usually offered surgery. Boyd and McLeod [11] and Posch, Goldberg and Larrey [12] reported that up to 8% of patients require surgery. A variety of surgical procedures for treating tennis elbow has been described in the literature. One of them is tenotomy of the common extensor origin at the elbow. Many authors have now published their results of releasing the common extensor origin percutaneously using either the surgical blade or the hypodermic needle under general anesthesia [13]. It is a simple operation with minimal morbidity and good-to-excellent results in most of the studies.

The present study aims to analyse the correlation between NRS, DASH and Oxford scores after percutaneous tenotomy in patients with chronic tennis elbow.

Methodology:

This was a hospital-based prospective study conducted at department of Orthopaedics, Dr. Rajendra Prasad Government Medical College, Kangra at Tanda, HP, India for a duration of 1 year (2019-20). All patients of tennis elbow (>6 months duration) consenting to be part of the study during the study duration were enrolled in the study.

Inclusion Criteria

• 1.Lateral epicondylitis for a period of more than six months

• 2.Localised pain over lateral epicondyle

• 3.Positive chair lift test

• 4.No localized skin problems

• 5.Patients who gave consent

Exclusion criteria

• Lateral epicondylitis less than six months in duration

• Any previous elbow surgery

• Elbow pathology like Rheumatoid Arthritis, Osteoarthritis or radial tunnel syndrome

• Patients refused to give consent

Study procedure

Patients of treated tennis elbow coming for follow up visits were evaluated clinically and by NRS, DASH and Oxford scores at regular follow-ups. New patients of tennis elbow of duration more than six months were enrolled for prospective evaluation after informed consent which included explaining the disease and procedure in detail to the patients. Patients fulfilling inclusion criteria were treated by OPD based surgical procedure (Percutaneous tenotomy). Before embarking on therapy, patient was evaluated by history and examination of the patient, which included NRS, DASH and Oxford Elbow score measurements. Subsequently patients were followed up at 3 monthly intervals i.e. at 3^rd month, 6^th month and 9^th month and were evaluated by NRS, DASH and Oxford score.

Surgical Method

Percutaneoustechnique: In outdoor patient settings and under local anaesthesia one centimetre incision is given over the mid-point of the lateral epicondyle to reveal the common extensor origin. The elbow is flexed to protect the radial nerve. A small pair of artery forceps is manoeuvred under the common extensor origin which can thus be well visualised. It is then divided. The wrist is flexed to complete the defect and allowed one cm gap to be created at the common extensor origin. This gap is palpated to confirm that the procedure is completed. The wound is closed and local pressure is applied to create haemostasis. All patients are advised postoperatively to mobilise wrist and elbow many times a day and to repeat the following sequence: maintain the forearm in full pronation; fully extend the elbow; flex the wrist; flex the fingers. 

Outcome Assessment

Outcome was assessed by NRS, DASH score and Oxford elbow score at intervention, 3^rd month, 6^th month and 9^th month.

Statistical Analysis

The data was entered in Microsoft Excel sheet was analysed using Epi-info version 7.2. Data were expressed as frequency, percentages or mean/standard deviation. ANOVA was used to compare means and standard deviation.

Comparison of two categorical variables was done using bivariate analysis and spearman coefficient was calculated. A p value less than 0.05 was considered significant. 

During the study period, a total of 47 patients were enrolled to receive treatment by percutaneous method. There was lost to follow up of 2 patients at 6^th and 9^th month. The study results have been shown below:

Age and Sex

Age analysis showed that the patients' age ranged from 29-65 years with mean age of 47±9.8 years. There were a total of 47 patients and out of them majority of the patients were in age group of 41-50 years (18;38.3%) followed by 31-40 years age group in which there were 12 (25.5%) patients. The mean age of males was 49.75±9.76 and that of females was 44.13±9.25 years. Sex-based analysis showed that there were approximately same number of males (24;51.1%) and females (23;48.9%).

Out of all the patients, 33 (70.21%) presented with lateral epicondylitis of right side while 10 (21.27%) had problem in left side. There were 4 (8.5%) patients who had difficulty in both sides. 

NRS pain assessment

NRS was graded in 4 categories namely excellent, good, fair, and   poor   based on  the scale score. It was observed that at baseline, none of the patients was in the excellent and good category and 10 and 37 patients in fair and poor category respectively.

At 3^rd month, 29 patients were in good category with 14 and 4 patients in fair and poor category. There were 6 patients in excellent category at 6^th month which increased to 15 at 9^th month. In good category, the number decreased from 28 to 24 similarly the count in fair and poor category also decreased from 8 to 4 and from 3 to 2 at 6^th month to 9^th month respectively.

Dash Score

At baseline and at 3^rd month, there was no patient in excellent category as per DASH score which increased to 5 at 6^th month and to 15 at 9^th month. The count in good category increased from 2 at baseline to 17 at 3^rd month and to 31 at 6^th month but later decreased to 24 at 9^th month with overall increase from baseline. In poor category, there were 28 patients at baseline which decreased to 2 at 6^th and 9^th month.

Oxford Score

Our study observed that Oxford elbow score was significantly improved at 3-months (32.58±2.68 vs 26.54±2.91; p = 0.001), 6^th month (36.04±3.03 vs 26.54±2.91, p = 0.001) and at 9^th month (39.78±2.71 vs 26.54±2.91; p = 0.001) in males when compared with baseline. In females, the score significantly improved at 3^rd month (30.3±3.79 vs 25.04±2.65; p = 0.001), at 6^th month (34.18±5.23 vs 25.04±2.65; p = 0.001) and at 9^th month (37.55±5.93 vs 25.04±2.65; p = 0.001) when compared to baseline score.

On bivariate analysis of NRS score at baseline with NRS score at 3^rd, 6^th and 9^th month and with DASH score and Oxford score at baseline, 3^rd, 6^th and 9^th month, it was observed that all had positive correlation with NRS baseline except Oxford score with negative relation and all the variables had significant association with NRS baseline score.

There was significant evidence of a positive relationship between NRS score at 9^th month and DASH score at 9^th month (r = 0.852, p value<0.001).

There was significant evidence of a negative relationship between NRS score at 9^th month and Oxford score at 9^th month (r = -0.841, p value<0.001).

There was significant evidence of a negative relationship between Oxford score at 9^th month and DASH score at 9^th month (r = -0.765, p value<0.001).

Table 1: Distribution of Patients on the Basis of NRS Grading

Table 2: Distribution of Patients on the Basis of Dash Grading

Table 3: Correlation of NRS-Baseline with Other Scores

Figure 1: Scattered Plot of NRS at 9^th Month vs Dash Score At 9^th Month

Figure 2: Scattered Plot of NRS at 9^th Month vs Oxford Score at 9^th Month

Figure 3: Scattered Plot of Dash at 9^th Month vs Oxford Score at 9^th Month

A total of 47 patients were enrolled in the study to receive treatment by percutaneous method with lost to follow up of 2 patients at 6^th and 9^th month. 

Age and Sex

In the present study, the majority of the patients were in 41-50 years age (Range 29 to 65 years). Flatt AE [14] suggested that tennis elbow can occur at any age; however, 31-50 years was the age-group most commonly affected by tennis elbow. Dimberg L [15] suggested that there is a positive relation of tennis elbow with age, where the prevalence of the disease increases with advancing age. Shiri et al. [1] has shown that most of the patients with tennis elbow were of age-group of 45-54 years. The age range mentioned in contemporary literature was identical to our study.

Males were more frequently affected than females with a male to female ratio of 1.04:1. This was quite expected as males are more exposed to manual work in hilly terrains. Walker-bone et al. [16] have explored the relationship between occupational exposures and lateral and medial epicondylitis and the effect of epicondylitis on sickness absence in a population sample of working-aged adults. They found that the most of the patients with Tennis elbow were females (55%) which are opposite to our observations.

Pain Assessment

Numerical Rating Scale (NRS): Our study found that pain was statistically significantly decreased at 3^rd, 6^th and 9^th month when compared with baseline. NRS improved from 6.92±0.71 to 1.57±1.44 in males and from 7.3±0.76 to 2.05±2.03 in females which was statistically significant. Literature review also reported improved functional outcome with percutaneous tenotomy in patients with tennis elbow as observed by Lin et al. [17], Panthi et al. [18] and Kayastha N et al. [19].

Lin et al. [16] investigated the effectiveness of the percutaneous soft tissue release (using a needle) for the treatment of recurrent myofascial pain in the forearm in six study subjects who had recurrent lateral epicondylitis. For every individual case, the pain intensity was significantly reduced (p<0.01) and the pressure pain threshold and the grasping strength were significantly increased (p<0.01) immediately after the treatment. This significant effectiveness lasted for at least one year. They concluded that needle based percutaneous soft tissue release could be effectively used for treating chronic recurrent lateral epicondylitis to avoid recurrence.

Panthi et al. [20] measured the outcome of percutaneous release of tennis elbow in 50 subjects with resistant tennis elbow in a nonrandomized controlled trial using a 18G Hypodermic needle. They found a significant improvement in pain intensity of visual analog scale. An excellent outcome was noticed in 24 patients (48%); Good result in eight patients (36%); Fair in four patients (eight percent) and Poor in four patients (eight percent). While, in our study there were 15 (31.9%) patients with excellent outcome, 24 (51%) with good outcome, 4 (8%) with fair and 2 (4%) with poor outcome. Kayastha N et al. [21] in their study observed that 11 (36.7%) out of 30 elbows had an excellent outcome, 13 (43.3%) had good, 5 (16.7%) had fair and 1 (3.3%) had poor outcome.

Our study results are in concordance with the other studies where pain intensity was significantly decreased by percutaneous method of treatment.

DASH Score

Our study found that DASH score was statistically significantly improved at 3^rd, 6^th and 9^th month when compared with baseline. The DASH score improved from 73.46±10.57 at baseline to 29.7±10.23 after 9 months in males while in females the score improved from 78.52±8.59 at baseline to 34.18±14.97 after 9 months.

Literature review also reported improved functional outcome with percutaneous tenotomy in patients with tennis elbow. [22]

Nazar et al. [23] presented the long-term results of percutaneous tennis elbow release in patients when conservative measures including local steroid injections failed to relieve the symptoms. They found that the postoperative outcome was good to excellent in most patients. Eighty-seven percent of patients had complete pain relief. The mean post-op DASH score was 8.47 (range 0 to 42.9). They found that percutaneous release of the epicondylar muscles for humeral epicondylitis has a high rate of success, is relatively simple to perform, is done as a day care procedure and has been without complications. Percutaneous release is a viable treatment option after failed conservative management of tennis elbow.

Dunkow et al. [24] compared the outcome of percutaneous release and open release for tennis elbow. They have shown that there was a significant difference in outcome in the two patient groups. Those patients undergoing a percutaneous release returned to work on average three weeks earlier and their symptoms as shown from their DASH scores improved significantly more than those undergoing an open procedure. The percutaneous procedure was a quicker, simpler procedure to perform than an open procedure. The study showed that patients have significantly better outcome measures after a percutaneous procedure.

Afzal et al. [25] assessed the efficacy of the operative technique in a prospective controlled trial in patients with tennis elbow. They showed that the median preoperative DASH score was 78 (67-86). The median basic normalized DASH score was 70 (64-75). The median postoperative basic normalized DASH score was 53 (48-57). The change in the median basic DASH score was 17 (11-19). The sports function section of the DASH score showed preoperative normalized median scores of 68 (65-78). The change in the median normalized sports scores was 11 (6-19). The patients were also scored according to the high performance and work section of the DASH questionnaire. The median preoperative work score was 68 (60-72). The median postoperative score was 52 (49-59) producing a change in the median score of 14 (7-20) (p<0.11).

Oxford Elbow score

Our study found that Oxford elbow score was statistically significantly improved with time at 3^rd, 6^th and 9^th month. The score improved from 26.54±2.91 at baseline to 39.78±2.71 after 9 months in males and in females the score improved from 25.04±2.65 to 37.55±5.93. The same results have been observed by Grundberg et al. [26], Nazar et al. [22], Baumgard and Schwartz [19] and Yerger and Turner [28,29]. 

Grundberg et al. [30] had operated on 32 patients using the percutaneous technique as we have used and followed up for an average period of 26 months and evaluated the outcome using a scoring system similar to ours. They reported 29 out of 32 elbows had excellent or good results (90%) and three cases (10%) had unsatisfactory results.

In another study done by Nazar et al. [31] on 30 elbows using percutaneous release, percutaneous release significantly improved Oxford elbow score in the patients with tennis elbow with 87% of the patients having complete pain relief. Baumgard and Schwartz [19] achieved excellent results in 32 of 35 patients they operated using the percutaneous technique. Similarly, Yerger and Turner [32] reported more than 90% excellent or good results in 149 patients they operated.

In our study, there were a total of 47 patients, with history of chronic tennis elbow for more than 6 months duration, enrolled for the study with lost to follow up of 2 patients at 6^th month onwards. There were 24 males and 23 females. Patients' age ranged from 29-65 years with mean age of 47±9.8 years. 33 patients had tennis elbow of right side while 10 had problem on left side. 4 patients presented with difficulty on both sides. As per NRS score, at 9^th month, there were 15 patients with excellent score, 24 with good and 4 with fair score. 2 patients had poor outcome after 9^th month. As per DASH score after 9 months, 15 patients had excellent outcome and 24 had good outcome. Fair outcome was observed in 4 patients and poor in 2 patients.There was statistically significant improvement in the mean scores (NRS, DASH and Oxford) of patients at baseline and after 9 months.

Recommendations

Patients with Chronic Tennis Elbow (>6 months) is a unique group which require special consideration. Many treatment modalities are available to address this subgroup patients with tennis elbow, Percutaneous Tenotomy has proven to be a reliable treatment method which has given sustained and improved outcomes without requirement of any additional modality of treatment /medication option.

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