Calcific Tendinitis of the Hand and Foot: A Report of Four Cases

Calcific tendinitis most commonly occurs in the shoulder and less common locations include the hip, elbow, wrist, and knee (1-3). Its occurrence in the hand and foot has been sporadically reported in the literature (4-9). Clinically, calcific tendinitis of hand and foot is presented by severe pain, swelling, and erythema, and is frequently misdiagnosed because of its rare incidence and its similar clinical presentation to other conditions such as infection, gout, or fracture (4-6).

The ultrasonography (US) and MR findings of calcific tendinitis of the hand and foot have been rarely reported in the literature (7, 8). Awareness of the typical location as well as familiarity with the imaging findings is essential for making a correct diagnosis of this condition. We describe the radiography, US, CT, and MR imaging findings of four cases of calcific tendinitis occurring in the hand and foot.

Calcific tendinitis is a common disorder caused by calcium hydroxyapatite deposition in a tendon. This condition has been described in nearly every tendon in the body, but occurs predominantly in the shoulder (1, 2). Less common locations include the hip, elbow, wrist, and knee (3). Calcific tendinitis of the hand and foot is an uncommon condition and is often misdiagnosed. In the hand, calcific tendinitis most commonly involves the flexor carpi ulnaris tendon near the pisiform bone and has been reported involving both the flexor and extensor tendons of the hand (4-8). Reports of cases in the foot are scarce, including peroneus longus tendon, flexor hallucis tendon, and lumbrical and interosseous tendons (9).

Clinically calcific tendinitis of the hand and foot is characterized by pain, tenderness, swelling, erythema, and restriction of motion secondary to pain. These acute presentations are usually self-limited within 3-4 weeks with conservative treatment. Calcific tendinitis of the hand and foot is frequently misdiagnosed because of its rare occurrence and its clinical resemblance to other entities (4-7). Clinical presentation may simulate acute infection, avulsion fracture, gout, or pseudogout. Many of the cases reported in the literature were often inappropriately treated with antibiotics or even surgery (6).

Radiographically, amorphous calcifications are found adjacent the cortex of the bone, and radiographs will often allow the correct diagnosis to be made. Additional oblique radiographs may be necessary because small calcifications can be missed easily. Rarely, calcifications may not be visible on radiographs. The initial radiographic diagnosis may be delayed due to unusual location of calcification. Often calcific tendinitis of hand and feet will be evaluated with CT, US, or MR imaging first because of a initial presumptive diagnosis of infection rather than calcific tendinitis.

CT is superior to radiography for the detection and delineation of the intratendinous calcification than conventional radiography. CT is recommended when radiography fails to detect calcifications. US is useful in determining the precise status of the tendon and has already been suggested to be a diagnostic tool for patients with calcific tendinitis of the rotator cuff (2). US diagnosis of calcific tendinitis of the hand and foot have been rarely reported in the literature (8). US findings include hyperechoic calcific foci, a thickening of tendon, and increased vascularity on color Doppler US (3). Calcific foci show ovoid, mottled, or amorphous hyperechoic shadow with or without posterior acoustic shadowing. US allows confirmation of their intratendinous location.

MR findings of calcific tendinitis of the hand and foot have been reported sporadically (7). MR imaging is suboptimal for detecting soft tissue calcification. Calcification is seen as focus of low signal intensity on all imaging sequences, but is frequently quite inconspicuous. In addition to calcification, other MR findings of calcific tendinitis include inflammatory edematous soft tissue change surrounding the calcification and adjacent bone marrow edema (3). Bone marrow edema is common in the hip and shoulder, but has not been reported in the patients with calcific tendinitis of hand and foot. In our cases, medial sesamoid marrow edema was encountered in patients with calcific tendinitis of flexor hallucis brevis. MR imaging offers superior in detection of soft tissue and bone marrow edema, but may lead to false presumption of infection or other disease entities (3).

Calcific tendinitis of hand and foot is a self-limiting process and treatment is conservative. The traditional treatment includes oral nonsteroidal anti-inflammatory drugs, resting splint, local anesthetic/steroid injections, and puncture for aspirating the calcium deposit (4-7). Surgical evacuation is no longer advocated. Patient's symptom is usually reduced within 4-7 days after the acute onset of pain. On radiographs, calcific deposits disappear or markedly decrease within several weeks (5, 7).

Calcific tendinitis of hand and foot is a rare condition. It is often unrecognized because of its rarity and nonspecific clinical presentation and also because of unfamiliar MR findings and misinterpretation of initial radiographs. Here, four cases of calcific tendinitis of hand and foot were reported and may increase awareness of imaging findings of this rare condition.