Kevin J. Renfree
Etiology
The cause of lateral epicondylitis is poorly understood, although most likely a symptom of overuse microtrauma (a small tear) to the common wrist extensor tendon origin, usually the extensor carpi radialis brevis (ECRB). A commonly used term, epicondylitis inaccurately implies an inflammatory process. Numerous pathologic studies have confirmed vascular proliferation and focal hyaline degeneration in surgical specimens, most likely as a result of disrupted healing response, with fibrosis and granulation tissue forming rather than normal tendon. Nirschl has also used the term “angio-fibroblastic tendinosis” to describe the pathologic changes. This process leads to progressive shortening of the tendon, which may increase the chance of reinjury. Other authors have postulated that it may be a degenerative process with vascular compromise and hypoxia, similar to that found in rotator cuff pathology. A possible link to fluoroquinolone ingestion has also been proposed. Excessive eccentric loading may be a factor in the etiology of tendinopathy, as fewer muscle fibers are recruited to perform the work, which increases the stress load on each, resulting in an elevated risk for injury.
Epidemiology
Lateral epicondylitis is a common complaint, with an annual incidence between 1% and 3% in the general population. In one study, which attempted to identify industries at high risk for work related disorders of the neck, back, and upper extremity, epicondylitis was found to be the only one in which claims increased over a near-10-year period. Most likely the process is a cumulative one, resulting from the use of heavy hand-held tools or a combination of vigorous work, abnormal posture of hands and arms, and repetition. It is also very common in the dominant extremity of a typically average recreational athlete involved in racquet sports who may have a faulty single-handed backhand ground stroke. The commonly used term “tennis elbow” is unfortunately misleading, though, as only a small percentage (5% to 10%) of patients afflicted with this disorder play at all.
Pathophysiology
The specific areas of elbow abnormality include the extensor carpi radialis brevis–extensor digitorum communis (EDC) complex laterally. Pathologic specimens of patients operated on for this condition have not revealed any evidence of acute or chronic inflammation, although in vitro analysis of painful tendons has revealed the presence of interleukin-1 and cytokines. This molecular inflammation cascade could be a source of pain and dysfunction. One study in which catheters were inserted into tendons with tendinosis showed no prostaglandin E2, a component of inflammation. Higher levels of glutamate, a potent pain modulator in the central nervous system, were found, though, which may also be a source of pain in tendinosis. Although it is debatable whether radial nerve entrapment (analogous to carpal tunnel syndrome) causes the forearm discomfort seen in many cases of lateral epicondylitis, decompression of the posterior interosseous nerve may also be necessary to relieve the forearm pain and tenderness associated with lateral epicondylitis.
As mentioned, the cause of pain in lateral epicondylitis is poorly understood. Magnetic resonance images in patients with lateral epicondylitis have demonstrated thickening with separation of the ECRB tendon from the radial collateral ligament and abnormal signal change on the T1-weighted sequences. There were no associations between pathological signal intensity within the ECRB tendon on T1- and T2-weighted sequences, however, and the degree of self-reported pain. In one arthroscopic study, 31.3% of patients were noted to have a type I lesion, characterized as fraying of the undersurface of the ECRB; 31.3% had a type II lesion noted by linear tears within the ECRB; and 37.5% had a type III lesion, consisting of a partial or complete avulsion of the ECRB origin. Therefore, an overuse injury resulting in progressive disruption of the tendinous origin of the ECRB may produce an excessive inflammatory response during the healing process leading to pain and possible swelling and compression of the posterior interosseous nerve. If overuse of the tendon leads to the pain that patients experience, rest should decrease symptoms. Unfortunately, injections of the muscle with botulinum toxin, providing
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temporary paralysis of the painful common extensor origin, showed no benefit over placebo.
Diagnosis
Clinical Features
Patients with lateral epicondylitis typically are adults who report insidious onset of symptoms with no clear recollection of a traumatic event. The pain is localized to the lateral aspect of the elbow and proximal forearm. It is typically aggravated with activities such as lifting an object with the arm extended away from the body and the forearm in a pronated position. Tenderness along the lateral aspect of the elbow is present. Although rest pain is unusual, patients often experience pain and stiffness in the morning while initially attempting to mobilize their elbow and wrist with their daily activities. Secondary stiffness of the elbow and wrist is uncommon, and if present, should prompt suspicion for an underlying articular disorder. Furthermore, any mechanical symptoms such as catching, locking, popping, or giving way may indicate an internal derangement of the elbow joint. Lateral epicondylitis is rare in patients in their teenage years or younger and should prompt a more aggressive workup.
Physical Examination and History
Overlying changes in skin color or temperature are not typically seen. Although swelling may be seen in a thin individual, it is uncommon. Tenderness is typically present about 1 cm anterior and distal to the lateral epicondyle, which is easily palpated in most patients. Although patients may also experience tenderness in the proximal forearm musculature, this may also indicate a coexisting radial tunnel syndrome, particularly if the tenderness is in the area of the radial tuberosity. Elbow motion is typically full, smooth, and painless, although some patients with severe epicondylitis may experience lateral elbow pain in full extension. If pain is present with passive forearm rotation, combined with elbow flexion and valgus stress, a radiocapitellar plica may be the cause. Elbow stability should be assessed with a posterolateral pivot shift maneuver while the patient is in a supine position. A careful neurologic exam should be performed, although it is unusual to find any deficits, even in a patient in whom radial tunnel syndrome is suspected. Pain in terminal extension with a bounce maneuver, especially in a throwing athlete, might be related to impingement from an olecranon spur. A common finding in tennis elbow is pain in the region of the lateral epicondyle during resisted extension of the middle finger (the Maudsley test). This may be owing to disease in the EDC muscle rather than compression of the radial nerve or disease within the ECRB. A positive chair test may be identified if pain is exacerbated when the patient lifts a chair with the affected arm in extension. If unilateral symptoms are present, diminished grip strength compared with the opposite side is often found, most likely is a reflection of painful wrist extension.
Radiographic Features
The role of radiographs in the clinical evaluation of lateral epicondylitis is unclear. In one study, standard anteroposterior, lateral, and radiocapitellar views of the elbow in patients with a diagnosis of lateral epicondylitis demonstrated calcification along the lateral epicondyle in 7%. In only two of the 294 sets of films did the radiographs alter management. The author concluded that obtaining radiographs as an initial step in the evaluation of patients with lateral epicondylitis is not necessary. Certainly in patients who present with atypical symptoms such as night pain and mechanical abnormalities, radiographs are recommended.
Although the use of ultrasound has been described for the diagnosis of tennis elbow, magnetic resonance imaging (MRI) is a more sensitive modality to diagnose and evaluate treatment response, although rarely necessary in my opinion. MRI of epicondylitis demonstrates tendon thickening with increased T1 and T2 signal, but these findings may be seen in a small minority of asymptomatic individuals. Tears of the extensor origin may be identified, and anconeus edema, previously demonstrated on MRI in epicondylitis, is rarely found. Increased marrow T2 signal within the involved epicondyle is occasionally seen. Abnormalities of the lateral collateral ligament complex and areas of osteochondritis dissecans, which can also produce lateral elbow pain, may also be identified with MR imaging. CT scan and isotope bone scan may be helpful in distinguishing lateral epicondylitis from bony tumors such as osteoid osteoma.
Treatment
Surgical Indications/Contraindications
A poor prognosis for spontaneous recovery may be related to manual work and high baseline pain. If modifications to reduce physical demands during recovery cannot be realized, than operative treatment may eventually be necessary. One concept that is important to make the patient understand, however, is that (assuming all other diagnostic possibilities have been excluded) lateral epicondylitis is a condition in which pain may secondarily effect function. The surgical solutions proposed to correct it, therefore, are elective with very focused goals. If patients can live with their pain, or modify their activities in such a way as to make their symptoms tolerable, then surgery may not be advisable.
Nonoperative Options
The primary goal of nonsurgical treatment is to encourage healing of the abnormal tissue that produces pain. Most successful nonsurgical treatment programs center on the concept of an adequate, progressive rehabilitative resistance exercise program. Nonetheless, many modalities have been described in an attempt to hasten or improve the healing process. Unfortunately, many of these interventions have been advocated on the merit of insufficient evidence, contradicting results, insufficient power, short-term follow-up, or a low number of studies per intervention. They
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may, therefore, not actually produce results superior to rest alone, which can be expected to result in improvement in 80% to 85% of patients. Although rest is important with respect to avoiding symptom-provoking activities, complete rest is ill advised as muscle atrophy may begin within 6 days of complete disuse.
As mentioned, physical therapy is probably the most commonly used nonoperative treatment modality. In one systematic review of many studies on various modalities (laser therapy, electrotherapy, exercises, mobilization techniques, and ultrasound), weak evidence for efficacy was found only for ultrasound. Other studies have failed to demonstrate any additional benefit of including phonophoresis with a topical corticosteroid to ultrasound. With strengthening, eccentric contraction should be emphasized. Eccentric strengthening may help to heal tendinopathies by stimulating mechanoreceptors and tenocytes to produce collagen. Animal experiments have shown that eccentric loading improves tendon collagen alignment and simulates formation of collagen cross-linkage to improve tensile strength. In addition, tendon cells respond to an eccentric mechanical load by up-regulation of gene expression for synthesis of collagen proteins. One large Dutch randomized, controlled study found that, after 12 months, the success rate in the physiotherapy group (91%) was significantly higher than an injection group (69%), but only slightly higher than in a “wait-and-see” group (83%).
Brace treatment might be useful as initial therapy. Overload of the wrist extensors, which is considered to be a major pathogenic factor in lateral epicondylitis, has been shown to be reduced by braces. Forearm/hand splints are not more effective than elbow bands as a treatment for lateral epicondylitis, and currently no definitive conclusions can be drawn concerning the effectiveness of orthotic devices for lateral epicondylitis.
Most authors recommend treatment with nonsteroidal anti-inflammatory medications (NSAIDS), despite the growing evidence that the condition is noninflammatory. Nonetheless, these medications may be helpful in decreasing the level of pain, at least in the short term, but must be weighed against the risks of gastrointestinal adverse effects. There is also evidence that topical NSAIDS are similarly effective in the short term, and without the gastrointestinal risks. These compounds can typically be produced at many pharmacies or apothecary shops. A direct comparison between topical and oral NSAID has not been made, though. Some authors have expressed concern, however, as NSAIDS may inhibit the inflammatory response necessary for tissue repair. One study demonstrated that when NSAIDS were compared with placebo, tendon strength was reduced at 28 days.
Despite the fact that most evidence points to corticosteroid injections providing only short-term relief at best, lateral epicondylitis is the most common extra-articular use for corticosteroid injections by orthopedic surgeons. A meta-analysis review found superior short-term effects of corticosteroid injections for lateral epicondylitis, but it was not possible to draw firm conclusions on the effectiveness of injections owing to the lack of high-quality studies. No beneficial effects were found for intermediate or long-term follow-up. Other authors have reported on the use of an injection of autologous blood, felt to possibly provide the necessary cellular and humoral mediators to induce a healing cascade, with a reported 80% success rate. A double-blind, randomized, controlled trial comparing injections of botulinum toxin type A with those of a placebo (normal saline solution) in the treatment of chronic tennis elbow failed to find a significant difference between the two groups. Acupuncture also may provide improved pain relief in the short term when compared with placebo, but no clear long-term benefit has been demonstrated.
Numerous investigators have recommended extracorporeal shock wave therapy as an alternative treatment for chronic lateral epicondylitis of the elbow. The mechanism of action of shockwave therapy is not fully understood but may stimulate the healing process of damaged tendons and encourage revascularization, release of local growth factors, and the recruitment of appropriate stem cells to the area. Although some studies comparing low-dose or low-energy shockwave therapy with sham treatment demonstrated improvement in pain scores, most other studies have failed to demonstrate a clear benefit of this treatment modality.
Patient Selection
Studies on the natural history and surgical management of lateral epicondylitis have shown that surgical intervention is necessary in only 5% to 10% of patients. Only those patients with persistent or recurrent local pain and muscle weakness, nonresponsive to conservative measures for at least 6 months, should be considered for surgery. Symptoms of radial tunnel syndrome can resemble those of tennis elbow and result from compression of the radial nerve by the free edge of the supinator muscle or closely related structures in the vicinity of the elbow joint. It can be difficult to objectively differentiate these two disorders, and they may often occur simultaneously. Radial tunnel syndrome should be strongly considered in patients who have failed to respond to previous extensor release or debridement. Differential diagnostic injections can be helpful in distinguishing these two problems or confirming the presence of both. The first injection is given at the point of maximal tenderness, near the lateral epicondyle typically 1 cm anterior and 1 cm proximal with 3 to 4 mL of 1% plain lidocaine. After 5 to 10 minutes have elapsed, the patient is re-examined, and if pain is eliminated with provocative maneuvers (resisted wrist extension). and tenderness over the radial tuberosity region is diminished, then a diagnosis of lateral epicondylitis alone is appropriate. If, however, pain and tenderness persists, an injection is given toward the radial tuberosity with the forearm in supination with a long 25- or 27-gauge needle (Fig. 53-1). Once the needle strikes bone, it is redirected anteriorly and 10 mL of 1% plain lidocaine (a reasonable volume of local anesthetic is important) is injected. After 10 minutes, the patient is re-examined and if a posterior interosseous nerve palsy has been produced and pain is relieved, a posterior interosseous nerve decompression is included in the surgical plan. If pain persists following both injections, suspicion is raised for intra-articular pathology such as degeneration of the orbicular ligament or a redundant synovial fold, in which case a confirmatory intra-articular injection can be
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performed. This is particularly helpful in patients who have failed previous surgery for lateral epicondylitis.
My personal preference is an open procedure, in which case the patient is placed in the supine position with an arm board. If there is any suspicion of instability or intra-articular pathology, an examination under anesthesia is included, as well as a possible arthroscopy. The presence of a palmaris longus is confirmed, or alternate graft choices are discussed with the patient in advance
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Figure 53-1 With the forearm in supination, a fine gauge (1.5 in.) needle is directed anterior to the radial tuberosity in this patient with persistent pain after a previous open release of the extensor origin (surgical scar marked with indelible pen depicted by solid black arrow) suspected of having radial tunnel syndrome. |
Surgical Techniques
Percutaneous release can be done in an office setting and has a significant advantage of cost savings. Local anesthetic is injected at the point of origin of the ECRB. An 11 blade is then used to release the extensor origin from the epicondyle. The goal is to achieve about a 1-cm distal muscle slide to a new resting length. Immediate motion is allowed in a soft dressing. A more popular technique involves excising the abnormal tissue through an open incision, which I prefer to perform under a Bier block anesthetic. A longitudinal split is made between extensor carpi radialis longus (ECRL) and EDC tendons. After elevating the origin of the ECRL, the grayish-yellow pathologic tissue in the origin of the ECRB has a distinct fish-flesh appearance and consistency in contrast to the normal glistening longitudinal tendinous tissue (Fig. 53-2). It is excised in an elliptical fashion, with care taken to avoid injury to the underlying lateral collateral ligament. The underlying lateral epicondyle is then excoriated with a curette, and a small drill is used to create some channels for bleeding to promote scar and healing. One randomized double-blind comparative prospective trial has shown, however, that drilling conferred no benefit and actually caused more pain, stiffness, and wound bleeding than not drilling.
If the joint capsule is violated, I prefer to repair it with absorbable sutures to prevent a synovial cutaneous fistula from developing postoperatively (Fig. 53-3). The defect in the extensor tendon is then reapproximated. A soft, compressive dressing is applied and immediate gentle range of motion is encouraged. Alternatively, complete release of the extensor mechanism, debridement of abnormal tissue, with reattachment of the extensor origin back to lateral epicondyle out through drill holes can be performed. A V-Y lengthening, or slide, of the common extensor origin has also been described with good results. One must limit lifting and activities for 6 weeks following these latter two procedures to prevent detachment of the extensor origin in the postoperative period. In patients with persistent pain requiring revision surgery, or in whom a synovial cutaneous fistula has developed after a previous release, a wider debridement of the extensor origin may be performed with coverage using a vascularized rotational pedicle flap of the anconeus muscle.
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Figure 53-2 Intraoperative photograph of a patient with refractory epicondylitis. Solid black arrow depicts area of tendon degeneration;open arrow depicts longitudinal rent in extensor carpi radialis brevis (ECRB) tendon. |
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Figure 53-3 Patient with a persistent subcutaneous synovial fluid collection after extensor origin debridement and arthrotomy, in whom the joint capsule was not repaired. |
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Arthroscopic release of the ECRB origin has also become a popular technique. This is accomplished using proximal medial and proximal lateral portals. It has an added advantage of addressing any intra-articular pathology, which has been reported in 19% to 70% of patients. Baker et al. have classified the arthroscopic appearance of these lesions as follows: type 1, a normal-appearing undersurface of the capsule; type 2, a horizontal rent in the capsule; or type 3, complete rupture of the capsule with exposure of the ECRB tendon. The capsule is removed to allow visualization of the origin of the extensor muscles and tendon. The debridement is then performed from proximal to distal and is complete when all visible abnormal tissue is excised, exposing muscle fibers with a healthy appearance. Elbow stability is not compromised as long as resection does not extend posteriorly to an intra-articular line bisecting the radial head. Contraindications to arthroscopic debridement include significant calcific tendonitis, previous ulnar nerve transposition since visualization must be from the medial side (proximal-medial portal), and significant ankylosis, which may lead to inadequate joint distention and an increased risk of vascular injury because of inadequate displacement from the portal site from incomplete distention. Denervation (Wilhelm technique) has also been reported as an effective method for relieving pain, and is accomplished blindly by detachment of certain muscles, as well as simultaneous indirect decompression of the posterior interosseous nerve.
Surgical Complications
Posterolateral instability may result from inadvertent release of the lateral collateral ligament, as this structure is confluent with the origins of the ECRB and EDC. When performing a percutaneous release, the surgeon should keep a thumb over the posterolateral aspect of the radiocapitellar joint to avoid extension of the scalpel. If a posterior interosseous nerve decompression is performed, direct injury or neurapraxia, particularly involving branches to the EDC, is possible. One must keep in mind during an arthroscopic release that cadaveric studies have demonstrated varying courses of the lateral and posterior antebrachial nerves, which place these superficial sensory nerves at risk during portal placement. The radial nerve is also about an average of 5 mm from the proximal lateral portal. Painful neuromas of the posterior antebrachial nerve have also been reported after open releases and can be treated with neuroma resection and implantation of the nerve proximally into the brachioradialis muscle. Synovial cutaneous fistulas can result if the capsule has been violated to a significant degree and not repaired sufficiently. Heterotopic ossification after lateral epicondylectomy, although rare, has also been reported.
Results and Outcome
As mentioned previously, most studies on lateral elbow pain are limited by methodologic weaknesses in selection and definition of the study population, length of follow-up, and analysis of prognostic factors. Outcome scores, such as proposed by Roles and Maudsley or DASH (Disabilities of the Arm, Shoulder, and Hand), are not routinely used, and even objective data such as grip-strength measurements with an extended elbow are seldom reported. Systematic reviews of interventions have confirmed that there is a surprising lack of published controlled trials of surgery for lateral elbow pain. Without a control group, it is very hard to draw any conclusions about the effectiveness of a given modality of treatment, since the natural history of the syndrome is uncertain.
Of the published studies, pain relief following open debridement or releases ranges from 78% to 97%, 91% to 96% after percutaneous releases, and 85% to 90% after denervation. Reported rates involving return to work average about 5 weeks following open, 9 to 21 days for percutaneous, and 6 to 15 days after arthroscopic releases. When reported, grip-strength improvements range from 30% to 100%, with a good result considered >90% compared with the uninvolved side. One prospective, randomized, controlled trial comparing formal open release with percutaneous tenotomy showed significant improvements in patient satisfaction, time to return to work, the DASH score, and sporting activities in the percutaneous group. In another retrospective comparison, 69% of open cases and 72% of arthroscopic cases had good or excellent outcomes. Patients treated with arthroscopic release returned to work earlier than patients treated with open release did, and they required less postoperative therapy. Poorer results have been reported in patients seeking compensation.
Suggested Readings
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