Influence of Tendon Neuroplastic Training in Grip Strength of Patient with Lateral Elbow Tendinopathy – A Case Report

Introduction

Lateral elbow tendinopathy (LET) is most commonly referred as lateral epicondylitis or tennis elbow and extensor tendinopathy. The term “epicondylitis” was first used by Coues in 1914, who assumed that the pathologic changes in this condition are inflammatory in nature. Nirschl and Pettrone identified some vascular infiltrations and immature fibroblast tissues at the origin area of the extensor carpi radialis brevis (ECRB) while doing a surgery. Subsequent studies have proposed that the process is probably degenerative, and no inflammatory response was observed in surgical pathologic specimen obtained from the lateral epicondylar area. Rayan and Coray proposed on two occasions that the term “lateral elbow tendinopathy” is an alternative term more appropriate than lateral epicondylitis or tennis elbow.¹

Extensor tendinopathy term directly points out the pathology of wrist extensor tendon, and this may not be applicable always as pain reproduced may be due to involvement of extensor carpi radialis brevis proximal tendon and also supinator sometimes. So, probably ‘Lateral elbow tendinopathy’ will be the best term for diagnosis and for clinical practice.²

A healthy tendon is always rich in type-1 collagen fibers which are parallelly oriented with side to side and end to end layers and also with slight wave pattern. Under pathological conditions like stress or immobilization conditions, there will be an altered dynamics of collagen turnover. New fibers of collagen in pathological conditions won’t follow the above orientation due to absence of physical force which leads to altered matrix orientation. Now, in the place of type 1 collagen, there will be relative increase in type 3 collagen fibers which are not organized as type 1 collagen fibers. So, ideally type 3 collagen fibers cannot handle or transmit the tensile forces effectively as type 1 collagen fibers which leads to further strain / injury to the part. These biomechanical changes are very common in stress and immobilized conditions.³

Recent studies demonstrated some alterations to occur in the motor cortex of patients. This includes measurable changes in excitability of corticospinal areas and short interval cortical inhibition. These motor control issues not been addressed with traditional passive treatments which can lead to incompletion of the treatment. Tendon Neuroplastic Training (TNT) consists both isometric and isotonic exercise training with an externally paced visual and audio cue. Patients will be performing a strength training manoeuvre that leads to loading the tendon. Instead of a self-paced eccentric and concentric manoeuvre, here the patient should match the exercise speed with the audio and visual cue which is provided by a metronome.⁴

Diagnosing lateral elbow tendinopathy is as follows: The symptoms/pain are reproduced by (1) Gripping activities; (2) Pain on palpating the elbow on lateral aspect (lateral epicondyle area); (3) Clinical tests such as resisted middle-finger or third finger extension and/or cozen’s test.⁵ In lateral elbow tendinopathy patients, power grip induces pain at the level of lateral epicondyle, because extensor carpi radialis longus (ECRL) and extensor carpi radialis brevis (ECRB) must work to counteract the flexion moment generated at wrist joint by the digital and wrist flexors. This activity of extensor muscle encourages the wrist and hand functional position, where flexor group of muscles can work efficiently by maintaining their respective length tension relationship and can produce the maximum grip strength.⁶

Many studies have been done on lateral elbow tendinopathy by using grip strength as an outcome measure. This case study aimed to evaluate the influence of TNT exercises on grip strength evaluation in functional position of elbow in the patient with lateral elbow tendinopathy.

Case Presentation

Informed consent was obtained from the patient and patient rights were maintained throughout the treatment. The patient was a 38-year-old female who complained of pain in the lateral aspect of her right elbow, 3-4 centimetres distal to the lateral epicondyle of humerus with six months duration of pain and the patient was a right-hand dominant person. Patient was an IT worker by profession with deskwork for more than nine hours per day. She presented with a history of pain that usually started after certain time of working on computer which was tolerable and later increased to become intolerable forcing her to abandon the activity. Pain in gripping activities was unbearable. No complains of cervical pain, elbow joint crepitus, stiffness, swelling, paraesthesia were noted. No history and family history of any systemic disorders like hypertension, diabetes, epilepsy and cancer was given. Previous treatment included ultrasound therapy, interferential therapy, LASER therapy five months prior, which provided only temporary relief.

Physical Examination

A thorough global and regional examination including observation, range-of-motion (ROM), Oxford Manual Muscle Testing (MMT) and orthopaedic testing (Cozen’s, Mill’s, Maudsley’s)4 was performed and notable findings are presented in Table 1. Posture analysis was done in search of any deformity. Head position, cervical lordosis and both shoulder positions were normal. Normal carrying angle was observed on comparison to other side.

Passive movements of neck and elbow were without pain, with muscle power 5/5 on Oxford scale. Passive shoulder movements were without pain and with muscle power 5/5 on Oxford scale. Scapular stabilizers demonstrated muscle power 4/5 on Oxford scale.

Wrist joint was tested for both passive movements and also under resistance. Passive wrist extension was without pain with full ROM and also had normal end feel. But passive wrist flexion was slightly painful near common extensor origin area with full ROM and normal end feel.

Pain free resisted wrist flexion was observed with muscle power of 5/5 on Oxford scale. Painful resisted wrist extension was observed over common extensor origin area with 8/10 on Visual Analogue Scale (VAS) and with the muscle power of 4(-) on Oxford scale.

Based on the history provided by the patient and the findings of physical examination, patient fitted into the diagnostic criteria of tendinopathy which includes pain on palpating the area, also while doing tendon loading, and the reduction of pain during activity, also known as the “warm-up phenomenon”. Hence, patient was diagnosed with lateral elbow tendinopathy. Patient reported pain as 8/10 on Visual Analog Scale when it aggravated.

Therapeutic Intervention

Patient underwent supervised exercise programme consisting of TNT (Table 2), static stretching exercises for extensor muscle group of wrist joint and isometric training for wrist extensors in both 90 degree elbow flexion and zero degree elbow extension positions to improve functional integrity. Patient continued with her regular duties at work which she could not avoid. Patient was instructed to avoid the activities that irritated elbow, like power grasping, knitting, lifting, mopping, and working with screwdriver.

The exercise involved isolated wrist extension and flexion with a weight cuff (Figure 1), paced to an external audio / visual cue on the patient’s smartphone (ProMetronome; https://tarskitheme.com/apps/com. eumlab.android.prometronome/). Patient was instructed to follow the sound and track the movement of the metronome according to the beats, as pacing to these types of external cues is shown to modulate corticospinal excitability. The metronome pace was set to 20 beats per minute which is like three seconds apart for each beat. Such that, concentric phase takes three seconds duration and eccentric phase takes three seconds duration. Four sets with eight repetitions were to be completed with a two-minute rest in between each set.  

Patient followed the exercise programme under supervision, five times a week for four weeks and weights used were individualized based on the patient’s pain or discomfort experienced during the procedure.^4,7

The static stretching exercises were also performed which were repeated six times at each treatment session, three times before and three times after doing the TNT and isometric exercises, with a 30-second rest between each. With the other hand help, stretching exercises for wrist extensor muscles were performed. Stretching procedure was done in the sequence of elbow full extension, full pronation of forearm, and flexion and ulnar deviation of the wrist as per the patient’s pain tolerance. A hold duration of 30-45 seconds was done each time. Isometric exercises for wrist extensor muscles were also performed with 10 seconds hold for each time and repeated for three sets with 10 repetitions in each set. In addition, rotator cuff muscles and scapular muscles were strengthened, and supinator muscle strengthening exercises were performed.⁷

Outcome Measures

Pain-free grip strength, Patient Rated Tennis Elbow Evaluation (PRTEE) questionnaire and VAS were taken as outcome measures in this study. Function and pain were measured, where pain-free grip strength was used to evaluate function and VAS was used to evaluate pain and finally, PRTEE was used to measure both pain and function.

Grip strength was measured by using Handheld dynamometer (CAMRY EH 101 Electronic Handheld Dynamometer). Measurement procedures were adopted from American Society of Hand Therapists with some modifications, where the participants were in high sitting position, elbow maintained at slight flexion of 40°, handle adjusted to the second position. The patient was explained about the procedure thoroughly, was asked to apply maximum force on the handle and hold that position for three to five seconds. This procedure was repeated in the same manner for three times with one minute interval between each procedure.⁸ The reported pain was 8/10 on VAS and the grip strength value was 10.2 kg.

Outcome measures were evaluated / recorded at week-0 (baseline), at week-4 (last day of the treatment) and at week-12 (two month after the end of treatment).

At baseline, reported pain was 8/10 on VAS, the grip strength value was 10.2 kg and PRTEE questionnaire score was 71. After therapeutic interventions, at week-4, the grip strength was 24.3 kg, pain score on VAS was 1 and PRTEE questionnaire score was 8. At week-12, pain score on VAS was 0, PRTEE questionnaire score was 5 and grip strength was 31 kg (Table 3) (Figure 2).

There was a marked increase in grip strength with increment of 20.18 kg from baseline, marked reduction in pain score (VAS) with eight points and marked reduction in PRTEE questionnaire with 66 points at 12th week follow-up.

Discussion

The present study aimed to examine the influence of TNT exercises on grip strength of lateral elbow tendinopathy. To our knowledge, this is the first study that examined the grip strength in functional position of elbow in lateral elbow tendinopathy condition with TNT exercises along with scapular stabilization exercise intervention. Grip strength provides an objective index of the functional integrity of the upper extremity. Functional range of elbow joint between 30 – 130 degrees of flexion is sufficient to achieve most positional and functional tasks.⁹ Studies have proven that elbow position plays a foremost role in obtaining the values of grip strength. Chwen-Yng Su et al., mentioned in their study that, when grip strength was measured in elbow extension position, irrespective of shoulder position (which is 0° or 90° or 180° of shoulder flexion), there was a significant higher grip strength values than when the elbow at 90° flexion with the shoulder at 0° flexion position. They proved that, higher grip strength can be obtained with elbow in extension position rather than in flexion. This position maintains the optimal length of the muscle which enhances the optimal overlap between the actin and myosin that occurs at lengths just greater than the maximal resting lengths.¹⁰ Based on the above study, elbow position of 40 degrees has been selected for grip strength examination in our study to maintain the optimal length of the muscle by means of length-tension relationship of the muscle and also this position will be a long lever position without support which is the most functional position of daily living.

Many studies support the loading exercises in the eccentric training form for tendinopathy conditions to reduce pain and increase the tendon strength by stimulating mechano-receptors which are present in tenocytes for collagen production, which is a key cellular mechanism that is required for tendon injuries recovery and also induces the normalization of glycosaminoglycans concentration levels. Eccentric training may also help in alignment of collagen fibers of a tendon and enhances the formation of cross-linkage of collagen fibers to improve the tensile strength.^11,12 This training methodology addresses the tensile strength deficits present in tendinopathy through progressive loading, but fails to adequately address the deficits in the central nervous system. Motor control maladaptation and abnormal motor inhibition may be the potential factors for recalcitrance of the interventions. Despite having the cornerstone treating methodology for tendinopathies in the form of exercises, recurrence and bilateral occurrence are the major problems with tendinopathies. This is the reason for the evolution of a novel concept in rehabilitation of tendinopathies in the form of Tendon Neuroplastic Training which incorporates the fruitful exercise protocols with modulation of central nervous system (CNS) and better neuromuscular control aiming to induce neuroplasticity.

In chronic elbow tendinopathy conditions, functional deficit / dysfunction is the main concern for a person’s suffering. This functional deficit / dysfunction always should be addressed in the form of kinetic chain approach instead of focal treatment at only respective elbow level. Addressing the shoulder and scapula stability in elbow tendinopathy will give fruitful outcomes in functionality of a person. There are related studies which support strengthening of scapula in lateral elbow tendinopathy patients.¹³

Stasinopoulos stated that rehabilitation of lateral elbow tendinopathy is cvolving, and now eccentric training is not the only exercise option. He also stated that heavy and slow resistance exercise programme for LET gives promising results. But ideally, instead of opting any treatment approach as monotherapy, considering multimodal approach gives better results by combining the treatments like therapeutic modalities, manual therapy, bracing / taping and dry needling, Instrument Assisted Soft Tissue Mobilization (IASTM), etc. Similarly, low-intensity resistance exercises in combination with blood flow restriction can be considered along with other therapeutic procedures for the management of LET.^8,14 Reyhan Aycan Cakmak et al., concluded that Mulligan’s Mobilization with Movement (MWM) along with exercises and cold therapy is an effective treatment approach in alleviating the pain, improving the functional capacity and also in improving pain free grip strength in the patients with lateral epicondylitis.¹⁵ Other treatment options like shockwave therapy are available for the treatment of lateral elbow tendinopathy, but a level 1a systemic review done by Stefanos Karanasios and colleagues reported contradictory results with low to moderate certainty of evidence suggesting no clinical benefits of extracorporeal shockwave therapy compared to sham interventions and with other interventions.¹⁶

Main limitations of the present study were estimation of the grip strength measurement only in 40 degree elbow position. Lacking of other parameters like elbow in full extension and patient in standing position instead of sitting, could have influenced the outcome measures. Standing position will have continuous interaction between the central commands and sensory feedback from lower limb joint receptors and muscles. This adds more temporal and spatial summation of the contracting muscles with increased cortical and peripheral arousal. This synergistic effect of the lower extremity muscles may enhance the maximal grip force while standing.

Another limitation of the present study was not having a large sample group. Being a case study, these results cannot be applicable to all lateral elbow tendinopathy patients. Each patient must undergo individual evaluation process and appropriate treatment. Strong recommendation can be made to conduct high-quality randomized control trails to support the above results and also to control the unidentified confounding factors. Future studies should be conducted to evaluate the grip strength in all elbow positions while patient is in sitting and also in standing positions. Another limitation of this study was the study duration as only a 12 week follow-up was done. Future long term follow-up studies where TNT protocol efficacy can be evaluated further are recommended.

However, the strength of this current study was evaluation of grip strength in 40 degree functional position of elbow in lateral elbow tendinopathy in patient who underwent TNT procedure. This functional position evaluation gives an insight about the functional recovery of patient where a patient was able to do the daily activities involving this position. Also, this gives scope for future studies as an insight to frame high-quality treatment regime and evaluation methodology.

This case demonstrated a positive outcome with Tendon Neuroplastic Training (TNT) which is a novel technique that improved the functional grip strength of a patient with lateral elbow tendinopathy. In conclusion, TNT exercises can improve grip strength and result in pain reduction in patients with lateral elbow tendinopathy with a multi model exercise approach. Future studies with high quality trails and long-term follow-up are very much needed.

Conflicts of Interest

None

Acknowledgments

It has been our privilege to acknowledge our patient, who cooperated with us with so much of patience. Also acknowledging sincerely Dr.Dhanajay Jayvel (P.T). sir for his continuous support and suggestions throughout the study.