Collapse deformities of the thumb are all too common in the presence of CMC joint arthritis. The Nalebuff Type III or “intrinsic minus” thumb deformity evidenced by CMC flexion, MP extension or hyperextension and IP flexion is the most common deformity.
This becomes a highly dysfunctional posture over time due to the loss of MCP flexion, web space shortening and thenar muscle atrophy - making moving the thumb away from the palm all but impossible.
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