Spade phalanges refer to a distinctive morphology of the distal phalanx in which the distal phalangeal tuft is widened and resembles the business end of a garden spade.
The classic association of spade phalanges is with acromegaly. The thought is that stimulation of new bone proliferation affects the hand characteristically at the distal phalanx (from excess GH, IGF-1 (insulin-like growth factor) and somatomedin-C). Often in the setting of the acromegalic hand, there is widening of the MCP, PIP, and DIP joint spaces (somatomedin-C affects chrondrocytes as well), which was not seen in this patient.
Spade phalanx may also occur as a normal variant, as in the above case. "Spur-like" excresences may also occur with degenerative change. Look for a cluster of associated acromegalic changes before attributing a spade phalanx to acromegaly.