Rupture of the radial collateral ligament of the metacarpo-phalangeal joint of the index finger: a report of three cases.

We have diagnosed and treated three patients with complete rupture of the radial collateral ligament of the metacarpo-phalangeal joint of the index finger. Rupture of the radial collateral ligament of the metacarpo-phalangeal joint occurs most commonly in the little finger and has not previously been reported in the index finger. Operative treatment is recommended in all cases, due to the significant stresses placed on the radial side of the M.P. joint of the index finger.