Kienbock disease, or lunatomalacia, is caused by avascular necrosis of the lunate after repeated microfractures or major fractures to the lunate following trauma to the wrist. Repetitive microtrauma to the wrist from repetitive compressive loading and unloading such as use of a jackhammer and recurrent compression of the lunate by the capitate and distal radius resulting from extreme wrist positions also has been implicated in the evolution of this painful condition of the wrist and forearm.
A patient with Kienböck disease reports unilateral dorsal wrist pain over the lunate that radiates into the forearm and decreasing range of motion of the wrist. Weakened grip strength also may be noticed. Kienböck disease usually affects one wrist; incidence of bilateral disease is extremely low. The disease is most common in the second through fourth decades of life with the wrist of the dominant hand affected in the majority of cases.
What are the Symptoms of Kienbock Disease
Physical examination of patients with Kienböck disease reveals pain on ulnar or radial deviation of the wrist, with the pain worsened by passively dorsiflexing the middle phalanx on the affected side. Pain is felt on palpation of the lunate, and a click or crepitus may be appreciated by the examiner when putting the wrist through range of motion.
How is Kienbock Disease diagnosed?
Plain radiographs are indicated in all patients who present with Kienböck disease to rule out underlying occult bony pathological conditions and identify sclerosis and fragmentation of the lunate. Based on the patient’s clinical presentation, additional tests, including complete blood cell count, uric acid level, erythrocyte sedimentation rate, and antinuclear antibody testing, may also be indicated. Magnetic resonance imaging (MRI) of the wrist and ultrasound imaging is indicated in all patients suspected to have Kienböck disease or if other causes of joint instability, infection, or tumor are suspected.
Computed tomography may help ascertain the condition of the articular cartilage. Electromyography is indicated if coexistent ulnar or carpal tunnel syndrome is suspected. A very gentle injection of the lunotriquetral joint with small volumes of local anesthetic and steroid provides immediate improvement of the pain, but ultimately surgical repair is required. Low-intensity pulsed ultrasound may help increase vascular growth factor, which is believed to increase blood flow to the affected bones of the wrist.
Coexistent arthritis and gout of the radioulnar, carpometacarpal, and interphalangeal joints; dorsal wrist ganglion; and tendinitis may coexist with Kienböck disease and exacerbate the pain and disability of the patient. Lunate cysts, contusions, and fractures also may mimic the pain of Kienböck disease, as can tear of the triangular fibrocartilage complex and ulnar impaction syndrome
Initial treatment of the pain and functional disability associated with Kienböck disease should include a combination of nonsteroidal antiinflammatory drugs (NSAIDs) or cyclooxygenase-2 (COX-2) inhibitors and short-term immobilization of the wrist. Local application of heat and cold also may be beneficial. For patients who do not respond to these treatment modalities, an injection of a local anesthetic and steroid into the lunotriquetral joint may be a reasonable next step to provide palliation of acute pain. Ultrasound guidance may improve the accuracy of needle placement and decrease the incidence of needle-related complications. Vigorous exercises should be avoided because they would exacerbate the patient’s symptoms. Ultimately, surgical repair is the treatment of choice.
Failure to treat significant Kienböck disease surgically usually results in continued pain and disability and in some patients leads to ongoing damage to the wrist. Injection of the joint with local anesthetic and steroid is a safe technique if the clinician is attentive to detail, specifically using small amounts of local anesthetic and steroid and avoiding high injection pressures, which may damage the joint further. Another complication of this injection technique is infection. This complication should be exceedingly rare if strict aseptic technique is followed. Approximately 25% of patients report a transient increase in pain after this injection technique, and patients should be warned of this possibility.
Kienbock disease and other disorders of the lunate are a relatively straightforward diagnosis in the presence of obvious antecedent trauma.
The diagnosis is less obvious in the absence of trauma, however, unless the clinician included it in the differential diagnosis with all patients with dorsoulnar wrist pain that radiated into the forearm.
Coexistent arthritis, tendinitis, and gout also may contribute to the pain and may require additional treatment with more localized injection of a local anesthetic and depot steroid. The use of physical modalities, including local heat and cold and immobilization of the wrist, may provide symptomatic relief. Vigorous exercises should be avoided because they would exacerbate the patient’s symptoms and may cause further damage to the wrist. Simple analgesics and NSAIDs may be used concurrently with this injection technique.