Central slip and bilateral lateral band laceration with negative Elson's and modified Elson's tests.

Elson's test is the gold standard clinical exam for assessing central slip integrity, but the test and its modifications were historically applied to isolated central slip injuries with intact lateral bands (Elson, 1986; Schreuders et al., 2006). This case report presents an open zone III extensor injury to the right index finger with complete laceration of the central slip and bilateral lateral bands. No prior reports of this injury, specifically one without any associated bony or neurovascular injury, have been explicitly described in the literature. Physical examination in this case demonstrated complete digital extensor lag at the interphalangeal joints, and false negative Elson's and modified Elson's tests. It is important to remain aware that complete laceration of the central slip and bilateral lateral band disruption is a possibility with zone III extensor lacerations. Importantly, Elson's test and its modifications have limited utility for these particular injuries, as the lateral bands cannot transmit extension forces to the terminal tendon.