Lunate osteochondrosis, also known as aseptic necrosis of the lunate bone, most commonly occurs between the ages of 20 and 30, and rarely affects individuals under 15 years old. It is more prevalent in males than females and more frequently seen in the right wrist than the left.

bubble_chart Etiology

Since the onset of this disease occurs late, when carpal bone development is already complete, many scholars believe it differs from typical osteochondrosis. However, pathological findings confirm it as a type of aseptic necrosis, though the exact disease cause remains uncertain. This condition is more common among manual laborers, particularly those using vibrating tools like pneumatic picks. Some patients have a history of wrist or hand injuries, leading to acute or chronic injury factors often being considered primary causes. Yet, many patients have no injury history. Gelberman found that 7% of lunate bones receive nourishment from only one or two slender palmar blood vessels, making them prone to aseptic necrosis. Others have noted that individuals with short ulnas are more susceptible, possibly because the lunate bone only contacts the radius, reducing the contact area and increasing stress, making it more vulnerable to injury.

bubble_chart Clinical Manifestations

There are three stages: ① Acute stage. Wrist pain, mild swelling, weakness, with or without a history of trauma. ② Resting stage. This stage is asymptomatic and can last for months. ③ Stage of attack. Wrist symptoms recur and persist, with tenderness over the lunate bone. Normally, the third metacarpal head is the most prominent when making a fist, but in patients, it often becomes lower or even depressed, known as Fislever's sign. The normal depression below the distal radius disappears. This is due to the shortening of the longitudinal axis of the lunate bone and an increase in its anteroposterior diameter. Pain is felt at the lunate bone when tapping the third metacarpal head. Late stage [third stage] presents symptoms of osteoarthritis.

X-ray findings: No positive findings are observed in the initial stage [first stage]. After several weeks to months, the lunate bone shows increased density, with a gradually appearing round or oval translucent area in its center. Subsequently, irregular fragmentation occurs. The longitudinal diameter of the lunate bone shortens, while the anteroposterior diameter increases. In the late stage [third stage], the proximal edge of the lunate bone appears irregular, fractured, or even absent. The joint space widens, and adjacent bones exhibit osteoporosis. In the advanced stage, changes of osteoarthritis become evident.

bubble_chart Treatment Measures

In the past, the method of long-term gypsum fixation was used, but it is now rarely employed because it does not prevent the continued necrosis of the lunate bone. However, in the acute phase or for patients with milder symptoms, temporary external fixation can be used to rest the wrist joint for a period. If symptoms are severe, surgical treatment may be considered. Currently, the commonly used method is lunate excision combined with silicone prosthesis implantation, which helps maintain wrist joint structure and yields better results than simple lunate excision. Some also use bone grafting or vascular implantation techniques in an attempt to restore the blood supply to the lunate, but the outcomes are not significant. Recently, there have also been reports of ulnar lengthening procedures. For patients with severe osteoarthritis, options include proximal row carpectomy, radiocarpal arthrodesis, or total wrist arthroplasty.

bubble_chart Differentiation

The diagnosis is not difficult and should be differentiated from lunate bone fracture, subcutaneous nodules of the wrist, and wrist wind-dampness arthritis.