Spontaneous flexor tendon ruptures of the hand: case series and review of the literature.

Spontaneous flexor tendon ruptures within the hand are incompletely understood. We report 5 cases of spontaneous tendon rupture involving the flexor digitorum profundus tendon. One case involves an abnormal intertendinous connection between the ring and small finger profundus tendons and another involves a lumbrical muscle variant. To our knowledge, the latter has not been reported in association with spontaneous tendon rupture. In reviewing the literature for spontaneous flexor tendon ruptures, a total of 50 spontaneous ruptures in 43 cases was found. The majority involve the profundus tendon of the small finger in the palm. The ruptures most often occur during periods of peak strain but can also occur without identifiable trauma. The pathogenesis of spontaneous tendon ruptures is still unclear and is likely multifactorial. Spontaneous flexor tendon ruptures of the hand occur more often than one might recognize.