Diminished distal dorsal finger crease is associated with handgrip weakness in inclusion body myositis

Background: Sporadic inclusion body myositis is a common cause of myopathy in populations over age 45 which classically causes distal finger flexor weakness. Loss of distal dorsal finger creases has been previously noticed in this disease. Aims: Investigate the association between distal finger creases and grip strength in patients with inclusion body myositis. Methods: We studied the crease pattern of the dorsal distal interphalangeal joints as well as handgrip strength in 81 affected and 74 control patients. Results: A subset of patients with inclusion body myositis who had loss of crease of the dorsal fingers had weaker handgrip strength. Conclusions: The loss of creases of the dorsal fingers is an additional complementary physical exam finding to identify inclusion body myositis and is associated with grip weakness.