Tendons may be cut across accidentally, especially in those wounds so commonly met with above the wrist as a result, for example, of the hand being thrust through a pane of glass.  It is essential that the ends should be sutured to each other, and as the proximal end is retracted the original wound may require to be enlarged in an upward direction.  When primary suture has been omitted, or has failed in consequence of suppuration, the separated ends of the tendon become adherent to adjacent structures, and the function of the associated muscle is impaired or lost.  Under these conditions the operation of secondary suture is indicated.

A free incision is necessary to discover and isolate the ends of the tendon; if the interval is too wide to admit of their being approximated by sutures, means must be taken to lengthen the tendon, or one from some other part may be inserted in the gap.  A new sheath may be provided for the tendon by resecting a portion of the great saphenous vein.

Injuries of the tendons of the fingers are comparatively common.  One of the best known is the partial or complete rupture of the aponeurosis of the extensor tendon close to its insertion into the terminal phalanx—­drop- or mallet-finger.  This may result from comparatively slight violence, such as striking the tip of the extended finger against an object, or the violence may be more severe, as in attempting to catch a cricket ball or in falling.  The terminal phalanx is flexed towards the palm and the patient is unable to extend it.  The treatment consists in putting up the finger with the middle joint strongly flexed.  In neglected cases, a perfect functional result can only be obtained by operation; under a local anaesthetic, the ruptured tendon is exposed and is sutured to the base of the phalanx, which may be drilled for the passage of the sutures.

Subcutaneous rupture of one or other of the digital tendons in the hand or at the wrist can be remedied only by operation.  When some time has elapsed since the accident, the proximal end may be so retracted that it cannot be brought down into contact with the distal end, in which case a slip may be taken from an adjacent tendon; in the case of one of the extensors of the thumb, the extensor carpi radialis longus may be detached from its insertion and stitched to the distal end of the tendon of the thumb.

Subcutaneous rupture of the tendon of the extensor pollicis longus at the wrist takes place just after its emergence from beneath the annular ligament; the actual rupture may occur painlessly, more frequently a sharp pain is felt over the back of the wrist.  The prominence of the tendon, which normally forms the ulnar border of the snuff-box, disappears.  This lesion is chiefly met with in drummer-boys and is the cause of drummer’s palsy.  The only chance of restoring function is in uniting the ruptured tendon by open operation.