Flexor Carpi Radialis Tendinitis
Flexor carpi radialis tendinitis is being seen with increasing frequency in clinical practice as golf and racquet sports have increased in popularity. The flexor carpi radialis tendon is susceptible to the development of tendinitis at its distal portion. The flexor carpi radialis tendon is subject to repetitive motion that may result in microtrauma, which heals poorly because of the tendon’s avascular nature. Exercise and repetitive trauma are often implicated as inciting factors of acute flexor carpi radialis tendinitis, with improper grip of golf clubs or tennis racquets and the prolonged use of a heavy hammer as the common inciting causes. Tendinitis of the flexor carpi radialis tendon frequently coexists with bursitis, creating additional pain and functional disability. Calcium deposition around the tendon may occur if the inflammation continues, making subsequent treatment more difficult. Continued trauma to the inflamed tendon ultimately may result in tendon rupture.
What are the Symptoms of Flexor Carpi Radialis Tendinitis
The onset of flexor carpi radialis tendinitis is usually acute, occurring after overuse or misuse of the wrist joint. Inciting factors include playing tennis, playing golf, and prolonged use of a heavy hammer. Injuries ranging from partial to complete tears of the tendon can occur when the distal tendon sustains direct trauma while the wrist is in full ulnar deviation under load or when the wrist is forced into full ulnar deviation while under load.
The pain of flexor carpi radialis tendinitis is constant and severe and is localized in the dorsoradial aspect of the wrist. Significant sleep disturbance is often reported. Patients with flexor carpi radialis tendinitis exhibit pain with resisted ulnar deviation of the wrist. A creaking or grating sensation may be palpated when the wrist is passively deviated radially. As mentioned, the chronically inflamed flexor carpi radialis tendon may rupture suddenly with stress or during vigorous injection procedures inadvertently injected into the substance of the tendon.
How is Flexor Carpi Radialis Tendinitis diagnosed?
Plain radiographs, ultrasound imaging, and magnetic resonance imaging (MRI) are indicated for all patients who present with ulnar-sided wrist pain. Based on the patient’s clinical presentation, additional tests, including complete blood count, erythrocyte sedimentation rate, and antinuclear antibody testing, may be indicated. MRI and ultrasound imaging of the wrist are indicated if joint instability or occult mass is suspected and to further confirm the diagnosis. Radionuclide bone scanning is useful to identify stress fractures of the wrist not seen on plain radiographs.
Flexor carpi radialis tendinitis is generally easily identified on clinical grounds; however, coexistent bursitis may confuse the diagnosis. Fractures of the distal radius and scaphoid and tears of the triangular fibrocartilage complex and avascular necrosis of the scaphoid also may mimic flexor carpi radialis tendinitis.
Initial treatment of the pain and functional disability associated with flexor carpi radialis tendinitis should include a combination of nonsteroidal antiinflammatory drugs (NSAIDs) or cyclooxygenase-2 (COX-2) inhibitors and physical therapy. Local application of heat and cold also may be beneficial. Repetitive activities responsible for the evolution of the tendinitis should be avoided.
For patients who do not respond to these treatment modalities, injection with local anesthetic and steroid may be a reasonable next step. Use of ultrasound guidance may improve the accuracy of needle placement and decrease the incidence of needle-related complications.
Trauma to the flexor carpi radialis tendon from the injection itself is an ever-present possibility. Tendons that are highly inflamed or previously damaged are subject to rupture if they are directly injected.
This complication can be greatly decreased if the clinician uses gentle technique and stops injecting immediately if significant resistance to injection is encountered. Approximately 25% of patients report a transient increase in pain after this injection technique, and patients should be warned of this possibility.
The flexor carpi radialis is a very strong tendon, yet it is also very susceptible to rupture. Coexistent bursitis and arthritis may contribute to wrist pain and may require additional treatment with a more localized injection of local anesthetic and methylprednisolone acetate.
Injection of the flexor carpi radialis tendon is a safe procedure if careful attention is paid to the clinically relevant anatomy in the areas to be injected. The use of physical modalities, including local heat and gentle range-of-motion exercises, should be introduced several days after the patient undergoes this injection technique for elbow pain.
Vigorous exercises should be avoided because they would exacerbate the patient’s symptoms. Simple analgesics and NSAIDs may be used concurrently with this injection technique.