**2.6 Difficult situations in primary tendon repair**

In major trauma where flexor tendon injury is associated with phalanx fracture, skin loss, tendon loss and neurovascular lesions, regular tenorrhaphy without traction is not possible. Two options are available in case the advancement procedures are not sufficient, in zone III, IV or V a bridge graft can be used to restore tendon continuity. A regional or local flap is utilized to cover the repair site and hence decreasing the potential adhesion formation. In zone II, if pulley and the flexor tendon sheath are damaged, it makes placement of transitory silicone tube (Hunters rod) necessary for creation of new digital sheath with smooth gliding potential. This procedure is labeled as "two stage tendon reconstruction", during the first operation in addition to placement of silicone tube, repair of the neurovascular bundle and skin is done along with reconstruction of the damaged pulleys. A second operation consists of replacement of silicone rod by a tendon graft through limited exposure (Hunter procedure).

The question of whether or not to repair an isolated FDP injury in zone II, it is necessary to assess the level of retraction of proximal stump. If contusion of surrounding soft tissue is limited and the proximal stump is not retracted into the palm, a direct atraumatic repair of the FDP tendon is recommended. But if the proximal stump is retracted into palm with avulsion of vinculum system, there are high chances of local fibrosis and adhesion formation after the FDP repair, therefore in such cases it is preferable to go for DIP tenodesis or fusion rather than to primary repair of the injured FDP tendon.

In case of partial flexor tendon laceration, the surgical technique depends on the total percentage of cross-sectional area of tendon involved: if the laceration involves less than 20% of the total diameter of the tendon, the tendon should be rounded off by local flap resection; to avoid a trigger finger, a partial resection of the pulley could helpful [41]; if the laceration involves between 20 and 50% of total diameter, a running simple peripheral suture should be sufficient; if the laceration is involving more than 50% of the diameter, a core suture through the injured part of the tendon with fine peripheral running suture is recommended.

### **2.7 Evaluation of results after repairing flexor tendon injuries**

For evaluating the results after tendon repair, many methods have been reported. American Society of Hand Surgery in 1976, proposed a method which measured the active flexion at MP, PIP and DIP joints and decreases in loss of extension for each joint. This value was then compared to the contralateral healthy finger.

Buck-Gramko [42] measured the distance from pulp-palmar, total active motion (TAM) and active extension loss of the finger. This method is lengthy and difficult to reproduce for each patient on every consultation.

Tubiana et al. [43] proposed a method of evaluation which was based on the PIP joint motion. This method evaluated the second phalanx position as compared to the metacarpal position; then the loss of active extension and active flexion of the finger can be precisely measured. This method evaluates the global function of the finger but does not measure the arc of mobility.

Strickland [16] reported a simple method, which counted the total active motion (TAM) of PIP and DIP joints. This method does not take movement across MP joint into consideration; based on the fact that flexion of MP joint is not under the control of only flexor tendons. TAM measured is compared to the contralateral finger to obtain a percentage of motion.
