HAND AND WRIST

SCAPHOID

Preiser's disease was described in 1910 by Preiser and represents spontaneous osteonecrosis of the carpal scaphoid. Some have interpreted Preiser's original case not as idiopathic ischemic necrosis but as a healing fracture. In fact, a history of trauma is frequent in patients who develop Preiser's disease. True spontaneous osteonecrosis of the carpal scaphoid is indeed uncommon.

Initial radiographic findings include cystic and sclerotic changes in the carpal scaphoid that are followed by collapse and in some cases fracture. These findings resemble those of Kienbock's disease and are usually involved in adults with local pain and tenderness. An interesting radiographic finding similar to that seen in calcium pyrophosphate dihydrate crystal deposition disease is narrowing of the radioscaphoid space. Chronic or repetitive stress and a predilection for the dominant hand have been recorded indicating that it is possible that Preiser's disease results from fatigue fracture of the scaphoid.

Preiser's Disease

Endstage AVN of the scaphoid

Cystic changes of osteonecrosis as a result of an ununited scaphoid fracture

Child with history of trauma to the wrist. Can you identify any abnormality?

LUNATE

Kienbock's disease was described in 1910 by Kienbock and represents avascular necrosis of the carpal lunate. Kienbock's disease is most commonly observed in patients from 20 to 40 years of age and has a predilection for the right hand in persons engaging in manual labor. Most cases are unilateral.

Frequently there is a history of trauma elicited but this is not constant. Clinically, progressive pain, swelling, and disability can be present. Radiographic changes are quite classic, however, their extent does not appear to correlate closely with the clinical findings. Initially a linear or compression fracture can be delineated and subsequently an increased density of the lunate bone is noted as well as an altered shape and a slightly diminished size. Eventually there is collapse and fragmentation particularly on the posterior surface. Other complications include scapholunate dissociation and secondary degenerative joint disease in the radiocarpal and mid carpal compartments of the wrist.

Pathologic descriptions have classically emphasized the occurrence of both fracture and osteonecrosis in Kienbock's disease. The cause of this condition is not clear, however, occurrence following a single or repeated episode of trauma is a prominent feature in many of these cases. It is possible that anatomical or biomechanical features of the lunate predisposes the bone to injury and subsequent osteonecrosis, including a vulnerable blood supply and its fixed position within the wrist which may increase stress on the lunate greater than the neighboring carpal bones when substantial force is placed on the carpal articulation. It is also possible that the presence of a short ulna, or negative ulnar variance could accentuate these mechanical forces and help lead to Kienbock's disease. The PA radiograph of the wrist obtained in a neutral position identifying the ulnarmost point of the articular surface of the radius and extending a line drawn perpendicular to the long axis of the radius through this point, is the most accurate method for determining ulnar variance. Negative ulnar variance is not infrequent while Kienbock's disease is rare so other factors must be important in the pathogenesis of this disease.

There are many methods used for the treatment of Kienbock's disease such as changing the length of the ulna or radius or even lunate replacement. As a general statement, the success of some of these techniques is increased by early diagnosis prior to collapse of the bone. MR imaging and scintigraphy may be indicated in some cases to follow-up and are quite sensitive to detect early osteonecrosis. MR imaging may be helpful as it provides early detection with diminished signal intensity on T1-weighted images and increased signal intensity on T2-weighted images in the regions of osteonecrosis and can also eliminate other diagnoses in some patients with wrist symptomology and often times may provide evidence of an alternative disease process.

ANV of the lunate

AVN of the lunate

AVN of the lunate

PHALANGES

Thiemann, in 1909, described a teenage boy with progressive enlargement of the proximal interphalangeal joints of the fingers. Additional reports over time indicate that typical clinical manifestations occur in the second decade of life, have a predilection for boys and typically are a painless swelling of the proximal interphalangeal articulations which can lead to deformity. The etiology is not fully delineated, however, the pathogenesis of this disease appears to be osteonecrosis.

Radiographically, irregularity of the epiphyses of the phalanges occurs especially in the middle fingers. The epiphyses then appear sclerotic and fragmented and may exhibit a medial and lateral osseous excrescence. Eventually joint space narrowing occurs. Some people have noted additional conditions that may accompany Thiemann's disease such as Legg-Calve-Perthes' disease, bipartite patella, and endocrine abnormalities such as thyroid enlargement and diabetes mellitus, however, a definitive association has not been verified. Differential diagnosis includes trauma, infection, thermal injuries, and juvenile chronic arthritis.