A comparative study of the efficacy of corticosteroid injection against ultrasound therapy in trigger finger.

Trigger finger (TF), also known as stenosing tenovaginitis or tenosynovitis, is an hand disorder due to hypertrophy of the tendon sheath at the intersection of the tendon with its pulley; the subsequent constriction on the tendon prevents it from gliding through ligament’s pulley, causing a sudden release or locking of a finger during flexion or extension, pain and functional limitation.1

Pinching of the tendon can lead to nodule formation and patients typically present with a locking, popping sensation as the nodule catches at the constriction.2

In some cases, it resolves spontaneously; however, if left untreated, trigger digit may gradually progress until the affected finger is permanently locked in flexion.

Histologically, the A1 pulley exhibits fibrocartilaginous metaplasia, and in the tendon tissue, areas of hyalinosis, mucoid degeneration, and chondral metaplasia are found.

Trigger finger is usually classified as an idiopathic condition, but some other etiologic hypothesis was proposed. It has been postulated that this disorder is caused by high pressure at the proximal edge of the A1 pulley and the discrepancy between the diameter of the flexor tendon and its sheath at the metacarpal head.3 Some authors argue that there is a possible correlation with hand overuse and repetitive blunt trauma. Other potential risk factors include rheumatoid arthritis, diabetes mellitus, carpal tunnel syndrome, Dupuytren’s disease, amyloidosis, hypothyroidism, mucopolysaccharide storage disorders, congestive heart failure, and genetic predisposition. However; the main etiology is still unclear.

Trigger finger is the most common flexor tendinopathy, with highest incidence is between 52 and 62 years and in women (75%). Thumb and fourth digit (ring finger) are the most commonly affected fingers, the right hand is more frequently involved compared to the left hand and the dominant hand is more frequently involved compared to the non-dominant hand.

Diagnosis of Trigger finger is based on history of pain, morning stiffness, h/o triggering and tenderness on the A1 pulley, and on clinical examination. Treatment aims to eliminate pain and stop triggering.

Trigger finger’s therapy can be divided into conservative and surgical treatment. The currently accepted conservative treatments included medications, usually oral NSAIDS , ultrasound therapy and local corticosteroid injection (CI), with rehabilitative interventions, including extension splint, physiotherapy programs, with mobilization and stretching exercises and physical therapy. Surgical treatment involves percutaneous and open release of the A1 pulley, and it’s recommended only when Trigger finger has been unresponsive to conservative therapies. Corticosteroid injection and surgery are reported to be effective for the remission of symptoms. Corticosteroid injection have the greatest success rate among conservative treatments, but they are effective only for some patients, and could predispose to tendon rupture when repeated over time. Surgery is associated with longer recovery times and more complications including tendon bowstringing, digital ulnar drift, and nerve injuries. Recently, extracorporeal shock wave therapy (ESWT) is getting popular as an alternative to surgery for the treatment of musculoskeletal disorders in patients unresponsive to conservative approach. Extracorporeal shock wave therapy has been reported to be effective in several tendinopathies, such as calcific tendinopathies of the shoulder.4 lateral epicondylitis of the elbow, patellar tendinopathy, hamstrings tendinopathy and plantar fasciitis.5

A variety of treatments have been described in literature for Trigger finger, but the most effective treatment is still under debate.