Hand function after injuries to the collateral ligaments of the metacarpophalangeal joint of the thumb.

An assessment was made of 34 patients who had sustained injuries to collateral ligaments of the metacarpophalangeal joint of the thumb. 23 patients had symptoms in the thumb, when seen at a mean of 38.7 months later, but these were minor in all but one patient. Assessment of pinch strength revealed that 43% of patients had less than 80% of the strength of the opposite side. This was not related to the presence of symptoms or to demonstrable instability of the joint, but the incidence of such weakness was greater when the operation had been delayed by more than three weeks. Pinch strength should be measured in two positions (key pinch and lateral pinch) as there is occasionally a large discrepancy between the two.