Treatment of tendon disorders. Is there a role for corticosteroid injection?

Tendon injuries and other tendon disorders are a source of major concern in competitive and recreational athletes and in many working conditions requiring repetitive movements. The exact etiology, pathophysiology, and healing mechanisms of the various tendon complaints are, however, only partly known and even origin of pain in the chronic tendon disorders is unknown. Thus, the treatment strategies recommended for tendon complaints vary considerably and the given treatment is frequently based on empirical evidence only. Corticosteroid injections are one of the most commonly used treatments for chronic tendon disorders. Despite their popularity, the biologic basis of their effect and the systematic evidence for their benefits are largely lacking. In addition to suppressing inflammation, the effects of local corticosteroid injections could be mediated through their effect on the connective tissue and adhesions between the tendon and the surrounding peritendinous tissues by inhibiting the production of collagen, other extracellular matrix molecules, and granulation tissue in these sites. Also, if the pain in tendinopathy is a result of stimulation of nociceptors by chemicals released by the damaged, degenerated tendon, corticosteroids might mediate their effect thorough alterations in the release of these noxious chemicals, the behavior of these receptors, or both. Achilles tendinopathy, rotator-cuff tendinopathy, tennis elbow, and trigger finger are among the most frequent tendon problems. There is good evidence, however, strongly supporting the use of local corticosteroid injections in the trigger finger only. This can be to the result of either a true lack of the effect or just a lack of good trials in the other complaints. Intimidation with adverse effects of peritendinous corticosteroid injections is based on case reports only rather than convincing data from controlled clinical studies. In light of the animal studies, corticosteroid injection into tendon substance should be avoided, although the true incidence of side effects after local corticosteroid injection(s) for tendon disorders is unknown. Also, the relevance of the steroid used, the tissue affected, the extent of the tendon problem, the duration of the symptoms, the phase of healing at the time of injections, and the postinjection events remain undetermined. Although a complete tendon rupture with loading after steroid injection has been reported, no reliable proof exists of the deleterious effects of peritendinous injections; conclusions in literature are based mainly on uncontrolled case reports that fail under scientific scrutiny, whereas scientifically rigorous studies have not been performed. An acute tendon disorder often responds favorably to early intervention with conservative treatment modalities. Local corticosteroid injections gives good short-term results in prolonged or subacute cases that do not respond to the conventional conservative treatments. Although corticosteroid injections are one of the most commonly used treatment modalities for chronic tendon disorders, there is an obvious lack of good trials defining the indications for and efficacy of such injections, and subsequently, many of the recommendations for the use of local corticosteroid injections do not rely on sound scientific basis. Thus, there is an obvious need for high-quality basic science studies and controlled clinical trials in examining the effects corticosteroids on various tendon disorders.