Knuckle pads are a variable finding of many conditions
Knuckle pads or Garrod pads are commonly associated with Dupuytren contracture. They are well-circumscribed, smooth, firm, and skin-colored slight elevations, papules, or nodules, approximately 0.5-3 cm in size. They are most commonly found on the back side of the hand at the main knuckles joints (metacarpophalangeal or MCP) and the first joints after them (the proximal interphalangeal or PIP), with the PIP being the most common site. They are not to be confused with a Dupuytren cord which is a structure associated with the lump on palm of the hand.
When associated with Dupuytren contracture, since they occur in 45-55% of cases, Garrod pads usually suggests a more aggressive representation of the disease (a Dupuytren diathesis).
When firm, the knuckle pads or nodules may be only tender to palpation, otherwise they do not cause pain or other symptoms. These nodules are closely adherent to the skin in Dupuytren contracture while movement of the nodule during finger flexion/extension suggests an association with the tendon sheath.
A history of repetitive injury to this part of the hand from work or sports activity is often present, as well as occurring without any physical explanation.
Garrod first described knuckle pads in the medical literature in 1893, but knuckle pads have been observed since the Renaissance era; Michelangelo’s statue of David has knuckle pads (Florence, Italy) as well as his statue of Moses (Rome, Italy).
In the U.S and the rest of the world knuckle pads are thought to be a common occurrence. The prevalence of knuckle pads is difficult to determine because this problem does not cause physical symptoms and so people do not often seek medical attention specifically for them. Knuckle pads can be present in any age group, with the most common in adults 40 years of age and older, especially males who engage in heavy manual labor. The condition also is seen in young children who suck their fingers.
Some cases of knuckle pads are clearly familial, having no other possible causation. Most often they are associated with other disease processes such as reported in Dupuytren disease, Peyronie disease, Ledderhose disease, pseudoxanthoma elasticum, esophageal cancer, hyperkeratosis, and oral leukoplakia.