Tennis elbow, also known as humeral epicondylitis, is a common clinical condition that is characterized by pain in the lateral aspect of the elbow when the patient grips and lifts objects with force. According to statistics, epicondylitis occurs in 10%-50% of tennis players; it can also occur in people with chronic repetitive inappropriate force activities.
It has been found that epicondylitis of the humerus is actually a degeneration of the tendon of the short extensor carpi radialis (ECRB) or the extensor digitorum communis (EDC), rather than a result of local inflammation. Moreover, the finding of neuropeptides at the radial short extensor carpi radialis suggests that neuroinflammation may be one of the reasons why patients develop pain in the lateral part of the elbow joint.
Etiology
The most common cause of tennis elbow is a tendon injury caused by repetitive forceful pulling of the forearm extensors, which occurs in patients between 35 and 50 years of age. Young or professional tennis players are at increased risk of developing tennis elbow due to overuse of the elbow joint. Some researchers suggest that tennis elbow may be caused by a failure of repair after tendon injury and local vascular damage. The normal tendon repair can be interrupted by subsequent injury, while the damaged tendon continues to impede tendon repair. prof. Cyriax believes that the muscle-bone junction is the most susceptible to injury because the tendon fibers there are relatively unsupplied with blood.
Clinical manifestations and physical examination
The main manifestations include pain in the lateral aspect of the elbow joint, which may radiate to the forearm and may be aggravated by gripping 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. Patients can be observed for lateral elbow pain by moving the cervical spine and performing the Spurlings test.
The stability of the scapula is important for tennis pumping, and without a stable point of force for the rotator cuff muscles, the function of the shoulder joint will be significantly limited. Thus, when a tennis player does not have enough shoulder strength to make a single draw, he uses the extensor muscles, which leads to overuse of the extensor muscles and degenerative tendon degeneration.
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 in elbow extension and forearm rotation in an anterior position with wrist extension or full flexion of the wrist joint
In addition, patients often have decreased grip strength due to pain in the 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 handheld 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.
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 deficiency 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. Manual therapy can also be used to treat tennis elbow, such as moving the affected limb or massage (Figure 1: massage of the wrist extensor muscle).
In addition, active muscle strength restoration programs such as wrist extensor restoration should be performed in conjunction with exercise restoration of the scapular and rotator cuff muscle groups. 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 (Figure 2: stretching the wrist extensors).
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 mimicking the production of collagen by mechanoreceptors that contribute to tendon recovery. It 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 mild 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. The patient completes 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 (Figure 4 Centrifugal strength training). The results of 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 among the studies. Most studies noted good results with 10-15 training sessions and a duration of 6-12 weeks.
Tennis players swing and hit the ball primarily by mobilizing the muscles of the scapula, shoulder and elbow, and injury to any of these areas increases the load on the extensor muscles. Clerks who use computers for long periods of time can also develop tennis elbow due to overuse of the wrist extensor muscles. Therefore, the primary treatment options for tennis elbow are pain relief, health education, and proximal muscle exercises. This includes core muscle strength training for rotational function of the shoulder and elbow joints, scapular muscle training, posterior rotation training with elevation of 45° and 90°, and diagonal patterns of D1 and D2 extension and flexion (proprioceptive neuromuscular easing technique) (Table 1).
Concentration of platelet plasma
If good results are not obtained with any of the above methods, platelet plasma concentrate (PRP) injections are recommended.PRP contains cell growth factors and cytokines that promote proliferation, differentiation, and maturation of human cells.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, by improving microvascular circulation to the tendon and surrounding muscle tissue to Reduced pain symptoms.
Surgical treatment
When conservative treatment of tennis elbow fails, surgical options include 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 degenerated tissue at the radial short extensor carpi radialis (if the common extensor tendon is involved, it should also be removed).
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-morbid 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 can also address 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 have been 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 higher mean shoulder, arm and hand dysfunction scores (Quick DASH, Disabilities of arm, shoulder & hand) and patients recovered better after surgery. The same results were obtained in the study by Peart et al. and the time to 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 around 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 on the anterior side of the lateral epicondyle of the humerus distally, and a plane is visible with the long radial carpal extensor on the anterior border and the common extensor tendon on the posterior border. The long radial carpal extensor is separated anteriorly so that the underlying short radial carpal extensor 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 external 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, and guidelines for routine rehabilitation exercises for postoperative patients are provided in Table 2.
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 have 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.