AI-powered Kienbock's disease detection on wrist MRI. Stage lunate avascular necrosis by Lichtman classification, assess collapse, and evaluate carpal alignment. 4 AI models detect early signal changes before X-ray findings.
Kienbock's disease is avascular necrosis of the lunate bone, the central keystone of the proximal carpal row. The lunate has a tenuous blood supply, making it vulnerable to ischemic injury from repetitive trauma, ulnar minus variance, or vascular anatomic variants. The disease progresses through stages defined by the Lichtman classification, from marrow edema through sclerosis, fragmentation, collapse, and ultimately carpal arthritis. MRI is the most sensitive modality for early detection and staging, often revealing signal changes before X-ray abnormalities appear. Our AI consortium analyzes wrist imaging to detect early lunate signal changes, assess disease stage, and evaluate carpal alignment.
The Lichtman classification defines disease progression: Stage I shows normal radiographs with MRI evidence of marrow edema as decreased T1 and elevated T2 signal in the lunate. Stage II demonstrates lunate sclerosis on radiograph without height loss. Stage IIIA presents with lunate collapse but preserved carpal alignment. Stage IIIB adds fixed scaphoid flexion and proximal capitate migration. Stage IV includes generalized radiocarpal and midcarpal osteoarthritis. Treatment is stage-dependent: Stage I to II may benefit from immobilization or revascularization, Stages II to IIIA from joint leveling procedures when ulnar minus variance is present, Stage IIIB from limited carpal fusion such as scaphocapitate or scaphotrapeziotrapezoid fusion, and Stage IV from proximal row carpectomy or total wrist fusion. Our AI stages disease to guide these decisions.
Ulnar minus variance, defined as the ulna being shorter than the radius by more than 1 mm on a standardized PA radiograph with the forearm in neutral rotation, concentrates compressive load from the radius onto the radiolunate articulation and reduces the force-sharing role of the TFCC. This anatomic variant is present in approximately 75% of Kienbock's patients compared to 20% of the general population. Joint leveling procedures including radial shortening osteotomy or ulnar lengthening osteotomy equalize the load distribution, reducing compression on the ischemic lunate. Our AI measures ulnar variance as a standard parameter in all wrist studies because of its direct therapeutic relevance in early-stage disease.
MRI detects Stage I Kienbock's disease by identifying bone marrow edema as decreased T1 and increased T2 signal before any structural abnormality is visible on radiograph or CT. This early detection window is therapeutically critical because intervention before lunate collapse, particularly joint leveling in the presence of ulnar minus variance or revascularization procedures, has substantially better outcomes than treatment after Stage IIIA collapse. CT is complementary for evaluating the presence and degree of coronal fracture lines within the lunate and for surgical planning but cannot detect the pre-collapse vascular compromise that MRI reveals. Gadolinium-enhanced MRI can also assess residual lunate vascularity by demonstrating enhancement in viable bone.
Decode your wrist MRI report including TFCC evaluation, scaphoid fracture detection, and carpal tunnel findings.
Lichtman stages I–IV of Kienbock disease — lunate avascular necrosis, MRI signal evolution, fragmentation, collapse, and treatment by stage.
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