Lateral epicondylitis (tennis elbow)

The pathophysiology of lateral epicondylitis involves a mechanism known as the tenodesis effect, which normally optimizes grip strength. This mechanism leads to overuse of the extensor carpi radialis brevis (ECRB) tendon, which becomes strained and damaged. This condition is usually precipitated by repetitive movements involving wrist extension and forearm pronation, making it common among tennis players, particularly those who frequently use backhand strokes. Anatomically, it generally begins with a micro-tear at the origin of the ECRB tendon, but can also involve micro-tears of the extensor carpi radialis longus (ECRL, long extensor carpi radialis muscle) and extensor carpi ulnaris (ECU, extensor carpi ulnaris muscle) tendons. Lateral epicondylitis is sometimes associated with radial tunnel syndrome, which coexists in around 5% of cases.

Symptomatically, patients typically experience pain when performing activities involving wrist extension or gripping against resistance. They may also report reduced grip strength. On physical examination, point tenderness or pain may be identified at the insertion site of the ECRB tendon in the lateral epicondyle. A neurological examination is important to differentiate lateral epicondylitis from other nerve compression syndromes. Decreased grip strength may also be observed. Provocation tests can be carried out to induce pain in the lateral epicondyle: wrist extension against resistance with the elbow fully extended, extension against resistance of the fingers, maximum wrist flexion and passive wrist flexion in pronation.

Imaging techniques play a supporting role in the evaluation of lateral epicondylitis. X-rays are generally normal, but in 20% of cases may reveal calcifications within the extensor muscle mass. Magnetic resonance imaging (MRI) is not usually necessary, but can provide additional information in complex cases. In around 50% of cases, increased signal intensity at the origin of the ECRB tendon can be observed, which may be due to tendon thickening, edema and degeneration. Ultrasound can be used, but requires an experienced operator; it can reveal a thickened, hypoechoic aspect of the ECRB tendon, facilitating diagnosis.

Conservative treatment is generally the first line of management for lateral epicondylitis. This approach aims to relieve symptoms and promote healing without the need for surgery. Activity modification, including reduction or avoidance of activities that exacerbate symptoms, is an essential component. The application of ice and the use of non-steroidal anti-inflammatory drugs (NSAIDs) can help relieve pain and inflammation. Physiotherapy plays an essential role and can involve various techniques such as exercises, stretching and ultrasound therapy. For tennis players, modifications such as playing on slower surfaces, using a more flexible racket with lower string tension and using a wider handle, can also reduce tension on the affected area. A counter-force splint, usually in the form of a strap, can provide additional support and take the load off the ECRB tendon. Steroid injections may be considered in some cases, with a maximum of three injections generally recommended. Other treatment options include acupuncture, iontophoresis/phonophoresis and extracorporeal shockwave therapy. The success rate of conservative treatment can be as high as 95%, but patience is required as healing and symptom relief can take time.

Surgical treatment of lateral epicondylitis is considered when conservative approaches have failed for a prolonged period, usually 6 to 12 months. Surgery is contraindicated in the case of an inadequate trial or non-compliance with non-surgical treatment. It is important to have a clear diagnosis of isolated lateral epicondylitis and to exclude any intra-articular pathology before considering surgery. The main aim of surgery is to release and debride the origin of the ECRB tendon, which is often the cause of pain.

There are several potential complications associated with treatment. Iatrogenic injury to the lateral ulnar collateral ligament can occur if it is excessively resected during surgery, so resection must not extend beyond the equator of the radial head. This can lead to posterolateral rotational instability, resulting in joint instability and functional limitations. Another complication is missed radial nerve compression syndrome, present in up to 5% of patients. Iatrogenic neurovascular damage, particularly to the radial nerve, can also occur during surgery. Heterotopic ossification (abnormal bone formation in soft tissue) can be another complication, but this risk can be reduced by abundant lavage after decortication. Infection is a potential complication, although relatively rare.

The prognosis for lateral epicondylitis is generally favorable, with non-surgical treatments effective in up to 95% of cases. Most patients experience significant improvement in symptoms and functional outcome. However, certain factors may increase the likelihood of requiring surgical management: ipsilateral radial tunnel syndrome (compression of the radial nerve at the elbow), a history of injections (e.g. corticosteroid), patients in whom a work-related accident is the cause of the pathology.