Tennis elbow (lateral epicondylitis of the humerus) is more common in clinical practice and is primarily caused by pain in the lateral aspect of the elbow when the patient grips and lifts objects with force. Statistically, epicondylitis occurs in 10-50% of tennis players. However, epicondylitis can also occur in workers who have repeated inappropriate force activities for long periods of time.
It has been found that epicondylitis of the humerus is actually a tendon degeneration of the radial short extensor carpi radialis (ECRB) or the extensor digitorum communis (EDC) tendon, rather than a result of local inflammation. However, the finding of neuropeptides at the radial short extensor carpi radialis suggests that neuroinflammation may be a cause for patients presenting with lateral elbow pain.
Therefore, Lee E. Rosenzweig, MD, from the Hospital of Special Surgery, summarizes the latest literature on the etiology, examination, and conservative and surgical management of tennis elbow in an article recently published in Techniques in Shoulder & Elbow Surgery.
Etiology
The most common cause of tennis elbow is a tendon injury caused by repetitive forceful pulling of the forearm extensor muscles, which is particularly likely to occur in patients between the ages of 35 and 50. Young or professional tennis players are at increased risk of developing tennis elbow due to overuse of the elbow joint. Also, lack of resistance in the skeletal muscular system predisposes to the occurrence of tennis elbow.
Some researchers suggest that tennis elbow may be caused by failed repair after tendon injury and localized vascular damage. Normal tendon repair can be interrupted by subsequent injury, while the damaged tendon continues to disrupt the repair of the disrupted tendon.
Professor Cyriax believes that the muscle-bone junction is the most susceptible to injury because of the relative absence of blood supply to the tendon fibers there.
Tennis players are prone to tennis elbow for both intrinsic and extrinsic reasons. The extrinsic cause is the use of too heavy a racket or too small a grip resulting in incorrect forces acting on the extensor digitorum communis tendon. The intrinsic cause is the chronic accumulation of microtrauma to the relevant tissues caused by the excessive use of the wrist joint during backhand strokes.
Clinical presentation and physical examination
The patient complains of pain in the lateral aspect of the elbow joint, which may radiate to the forearm and may be aggravated by grasping or lifting objects with the affected limb.
Physical examination should include an examination of the cervical spine, as pain due to nerve root compression at C5-C6 or C6-C7 can be misdiagnosed as humeral epicondylitis. The examiner can observe for lateral elbow pain by asking the patient to move the cervical spine and performing the Spurlings test.
After ruling out cervical spine problems, a thorough examination of the patient’s shoulder function is needed, including a strength test of the shoulder joint to assess the balance of contraction of the shoulder muscles. lucado et al. found that symptomatic female tennis players had a high upper trapezius/lower trapezius strength ratio.
Scapular stability is important for tennis pumping, and without a stable point of force for the rotator cuff muscle groups, shoulder function will be significantly limited. Therefore, when a tennis player does not have enough shoulder strength to make a draw, he uses the extensor carpi radialis, which leads to overuse of the extensor carpi radialis and degenerative tendon degeneration.
Lucado et al. found that symptomatic female tennis players had a significantly higher wrist flexion/extension strength ratio than asymptomatic women. It is likely that this muscle strength imbalance in tennis players is associated with the development of tennis elbow, while the development of tennis elbow in non-tennis players may also be associated with muscle imbalance.
Finally, palpation of the lateral epicondyle of the humerus reveals tenderness and pressure pain in the lateral epicondyle and anterior aspect of the forearm. Pain at the lateral epicondyle of the humerus can occur with the elbow joint extended and the forearm rotated anteriorly to extend the wrist joint or with the wrist fully flexed. If pain occurs during forceful fist clenching or restricted extension of the middle finger, degeneration of the radial carpal short extensors also occurs. When pain occurs with limited extension of the radial wrist joint or pressure pain in the humeral epicondyle indicates involvement of the radial long wrist extensor.
In addition, patients often have decreased grip strength due to pain in the lateral humeral epicondyle, a stable and sensitive diagnostic indicator of tennis elbow, so it is also necessary to measure the grip strength of the affected limb with a hand-held grip strength meter.
Neurological considerations
Diagnosis of tennis elbow also requires consideration of symptoms caused by abnormalities in the nerve structures, such as radial nerve entrapment syndrome and posterior interosseous nerve compression that can cause pain in the lateral elbow joint.
One study found that 5% of patients with humeral epicondylitis may have radial nerve compression because deep branches of the radial nerve pass behind the Frohse arch along the edge of the posterior rotator muscle fibers. When deep pressure pain in the radial head and limitation of forearm rotation posteriorly occurs, it indicates radial nerve injury, while pressure pain in the humeral epicondyle and limitation of wrist extension suggest that the patient has tennis elbow. The posterior interosseous nerve may be compressed at the point of entry into the posterior rotator muscle.
The pain of this type of nerve entrapment sign is more diffuse, whereas in tennis elbow the pain is concentrated in the forearm muscles distal to the lateral epicondyle of the humerus. Limited extension of the middle finger in elbow extension helps to differentiate neurologic disease, but the presence or absence of radial short carpal extensor muscle involvement must be determined.
In addition, the cervical nerve roots need to be evaluated for compression. Localized trigger points or chronic muscle spasm in the neck can also cause tennis elbow patient-like pain. One study suggests that severe chronic cervical nerve compression can result in a negative repeat strength test of the carpal extensors.
Conservative treatment
Nirschl et al. divided conservative treatment into three phases, based primarily on the acute inflammatory phase, the chronic inflammatory phase, and the muscle strength deficit phase. There are more conservative treatments, ranging from those aimed primarily at symptom relief to etiologic treatment. However, due to individual differences, there is still no uniform standard of treatment.
The first thing that is carried out is health education of the patient and correction of wrong activity patterns. The common conservative treatments for tennis elbow are ultrasound therapy, ultrasound drug penetration therapy, electrical stimulation, iontophoresis, heat therapy and cryotherapy. Manipulative therapy can also be used to treat tennis elbow, such as moving the affected limb or massage.
In addition, active muscle strength restoration programs such as wrist extensor restoration should be done in conjunction with scapular and rotator cuff muscle group restoration. Some researchers suggest that tennis elbow can be treated by stretching the wrist extensors and forearm muscles, with the wrist joint as if it were supported with the top cocked up, or by stretching with a reverse force.
If nerve root compression is suspected, symptoms of compression can be relieved by moving the joint, cervical traction and manipulative therapy.
Tennis elbow can also be treated with injections of non-steroidal anti-inflammatory drugs, cortisone, and concentrated platelet plasma.
Sling support
Sling supports are used to treat tennis elbow by reducing the load on the wrist extensor muscles during activity, and no relief of pain or restoration of grip strength has been observed in patients with tennis elbow treated with sling supports such as Struijs. Jansen et al. found that a semi-loop sling assisted wrist orthosis reduced elbow angle and improved electromyography of the radial short wrist extensors during lifting.
Van Elk et al. showed that the force of extension acting on the arm reduced the activity of the radial short extensor carpi radialis and the common extensor tendon when lifting objects in healthy people. The wrist extension force can be generated when grasping an object, which requires the arm extensors to stabilize the wrist joint.
During the acute phase of tennis elbow, a 30° wrist extension splint is worn for daily activities, and proximal limb functional exercises can be used to treat tennis elbow. In addition, wearing a reaction ring brace during exercise can help reduce discomfort.
Functional Exercises
Muscle strength and flexibility training can be effective in the treatment of tennis elbow, with centrifugal strength training considered to be the most effective method. It restores strength to the tendon by simulating the production of collagen by mechanoreceptors that help the tendon recover, and also improves the collagen cohort in the tendon and stimulates the formation of collagen cross lines, thereby increasing the tensile strength of the tendon.
Centrifugal strength training begins by immobilizing the forearm with the elbow and wrist in the extended position and making a fist. The patient uses the opposite hand to lower the affected wrist joint and then raises it to the original position. Each set is repeated 5-15 times for a total of 3 sets and is recommended to be done daily. It is normal to experience slight discomfort during training, but if the pain is severe, stop training immediately. Once the patient can easily complete the training, the resistance can be increased by adding gravity or rubber bands.
Another method of centrifugal strength training for the wrist is by tying weights to the end of a rope. Patients complete the centrifugal strength training by controlling the rise and fall of the weights through the handle, with the healthy arm holding the handle during the intervals of repetitive motion. The studies all showed significant pain relief, but the importance of the training, the weight of the weights, and the duration of the training varied from study to study. The majority of the studies noted good results with 10-15 training sessions and a duration of 6-12 weeks.
In addition, studies have found that muscle strength training combined with other treatment options, such as ultrasound, massage or orthopedic therapy, can be effective in relieving pain and restoring limb function.
Tennis players swing and hit the ball primarily by mobilizing the muscles of the scapula, shoulder and elbow, and an injury to any of these areas increases the load on the wrist extensors. Clerks who use computers for long periods of time can also develop tennis elbow due to overuse of the wrist extensor muscles. Therefore, the authors concluded that the primary treatment options for tennis elbow are pain relief, health education, and exercise of the proximal muscles (the most important part of tennis ball striking). This would include core muscle strength training for rotational function of the shoulder and elbow joints, scapular muscle training, posterior rotation training with 45° and 90° elevation, and diagonal patterns of D1 and D2 extension and flexion (proprioceptive neuromuscular easing techniques). In addition, both closed-chain and open-chain exercises can be used in the treatment process.
If none of the above-mentioned methods are effective, it is recommended to inject platelet plasma concentrate (PRP). PRP contains cell growth factors and cytokines that promote proliferation, differentiation and maturation of human cells.
Two recent studies have found that unactivated PRP containing leukocytes can be used as an alternative treatment option for tennis elbow in addition to surgical treatment, and have also yielded good clinical prognosis.
A multicenter study by Mishra et al. found significant pain relief in patients in the PRP injection group compared to the group with restricted wrist extension, but no statistically significant recovery of elbow function in either group.
However, none of these studies indicated the reason why PRP relieves pain in patients with tennis elbow, nor did they find changes in tendon structure. The authors of this article suggest that PRP reduces pain symptoms by improving microvascular circulation in the tendon and surrounding muscle tissue.
Surgical treatment
When conservative treatment of tennis elbow fails, surgical treatment options are available: incisional debridement and repair or simple debridement, percutaneous decompression, and arthroscopic debridement. Regardless of the surgical approach chosen, the principle of surgical treatment is the same: removal of degenerative tissue at the radial short extensor carpi radialis (and the common extensor tendon if involved).
In general, the majority of patients with tennis elbow showed significant postoperative symptomatic relief, and Nirschl et al. followed 130 patients with tennis elbow who underwent incisional debridement for up to 10 years, showing that 97% of patients showed significant symptomatic improvement and 93% returned to their pre-disease level of motion. In contrast, Thorton et al. used a modified surgical technique of Nirschl to fix the repaired tendon to the lateral epicondyle of the humerus with suture anchors, and the patient’s grip strength was well restored after surgery.
Arthroscopic debridement for tennis elbow can be equally effective and also allows for the management of intra-articular lesions, as Szabo et al. found that 44% of patients had a combination of intra-articular lesions. Another advantage of arthroscopic treatment is the short return to work time (11 days on average).
There are also many studies comparing the efficacy of the two surgical approaches. Solheim et al. followed 300 patients with tennis elbow for 3-6 years and although both groups had a good clinical prognosis, the arthroscopic group had a higher mean shoulder, arm and hand dysfunction score (Quick DASH, Disabilities of arm, shoulder & hand) and the patients recovered better after surgery. The same results were obtained in the study by Peart et al. and the return to work after surgery was shorter in the arthroscopic group.
Excessive debridement can damage the lateral collateral ligament of the elbow joint leading to postero-lateral rotational instability. The lateral collateral ligament can be well protected during arthroscopic debridement by keeping the lateral collateral ligament parallel to the superior half of the radial head. Complications such as heterotopic ossification and paralysis distal to the incision have also been studied.
Surgical technique
The patient is placed supine on the operating table with the affected limb abducted on a special surgical table for the hand and the scapula padded. A tourniquet is tied to the upper arm and a sterile towel is placed. An esmarch tourniquet is applied first to expel the blood and then inflate the tourniquet.
A 2-3 cm incision is made anterior to the lateral humeral epicondyle distally, and a plane is visible with the long radial carpal extensor muscle at the anterior border and the common extensor tendon at the posterior border. The long radial carpal extensor muscle is separated anteriorly so that the underlying short radial carpal extensor muscle can be exposed.
Since the degenerative tissue is light gray in color, it is easily distinguished from healthy tendon tissue, so complete excision of the diseased tissue is not difficult. In addition, the scratch test (scratch test) can be used to determine whether the debridement is complete.
A small suture anchor is then inserted into the lateral epicondyle of the humerus to thoroughly flush the surgical area of bone debris to avoid heterotopic ossification. The repaired radial short extensor carpi radialis is secured to the lateral epicondyle of the humerus with a suture anchor. Finally, the wound is closed layer by layer, and posterior lateral splinting for one week is sufficient.
Postoperative rehabilitation
A systematic and comprehensive postoperative rehabilitation program is essential to obtain a good functional recovery, in which an experienced physiotherapist is of paramount importance. Communication between the surgeon and the logistic therapist is very important because the rehabilitation process needs to take into account the surgical approach, the soft tissue situation, and the surgeon’s knowledge of rehabilitation. Guidelines for routine rehabilitation exercises for postoperative patients are provided in Table 2.
For patients who wish to return to exercise, pain-free movement in all directions and good muscle strength (at least 85% of the healthy limb) as indicated by a manual muscle test or isokinetic test must be achieved. A grip strength test with a hand-held dynamometer (at least 85% of the healthy limb) is also required.
During the return to exercise phase, floor pumping, serving, and monitoring the amount of exercise based on the patient’s response will be performed gradually. Initially, 15-20 minute intervals were used, and then the duration of exercise was gradually increased according to the patient’s tolerance level, but two consecutive days of exercise were prohibited.
The authors believe that a professional tennis coach is important for the prevention and rehabilitation of the patient’s tennis elbow. In addition, comprehensive ability training recovery and supplementary lower limb muscle exercises are also important for the whole tennis training process.
Conclusion
There are many reasons for the occurrence of pain in the lateral epicondyle of the humerus in tennis elbow, but there is still no standard treatment plan. Most patients can obtain symptomatic relief and functional recovery with conservative treatment, and the remaining patients can also obtain a good clinical prognosis with surgical treatment. In conclusion, more research is needed to prove the most appropriate method and amount of exercise and the treatment of tennis elbow.