Flexor tendon injuries

Abstract

Flexor tendon injuries have constituted a large portion of the literature in hand surgery over many years. Yet many controversies remain and the techniques of surgery and therapy are still evolving. The anatomical and finer technical considerations involved in treating these injuries have been put forth and discussed in detail including the rehabilitation following the flexor tendon repair. The authors consider, recognition and mastery of these facts form the foundation for a successful flexor tendon repair. The trend is now towards multiple strand core sutures followed by early active mobilization. However, the rehabilitation process appears to be one of the major determinant of the success following a flexor tendon repair. Early mobilization is essential for all the flexor tendon repairs as it is proved to improve the quality of the repaired tendon. The art of achieving the harmony between a stronger repair and unhindered gliding of the repair site through the narrow flexor tendon sheath simultaneously can be mastered with practice added to the knowledge of the basic principles.

Keywords: Core sutures; Early passive mobilization; Flexor zones of hand; Pulley system.

Fig. 1

Zones of the flexor tendon I–V (Thumb TI-TV).

Fig. 2

A small laceration at the wrist level has resulted in loss of the flexion cascade of index finger- indicating injury to its flexor tendons- ‘Finger tells the way’.

Fig. 3

Technique of applying a two-strand and a four-strand core suture in the flexor tendon.

Fig. 4

Looped suture – a needle has a loop of suture attached to it. Hence, providing a double suture across the repair site with a single passage.

Fig. 5

Technique of introducing a four strand suture using a looped suture.

Fig. 6

The recommended dimensions while introducing a core suture in the injured flexor tendon. The core suture should exit at about 1 cm from the cut end and the loop of suture should have a tendon substance bite of about 2 mm to have a good hold on the tendon.

Fig. 7

Two commonly used techniques of circumferential sutures- simple running suture and crisscross locking sutures.

Fig. 8

To make the tendon repair easy, it is better to first place the epi-tendinous suture in the posterior half of the tendon, then put the core suture and after tying the core suture complete the anterior half epi-tendinous repair.

Fig. 9

Brunner criss-cross incision shown in the ring finger and mid-lateral exposures incision shown in the little finger. The incision should never cross the finger creases perpendicularly.

Fig. 10

Position of tendon cut ends with respect to the finger position at the time of injury. A- When the injury happens with finger in extension (assault) the distal cut end will be close to the site of laceration. B- When the injury happens with the fingers in flexion (as while grasping a knife) the distal cut end would be very distal when the finger is kept extended while operating. Flexion of the finger will bring the cut end to the site of laceration.

Fig. 11

Results of zone-II flexor tendon injury, treated with primary repair followed by early passive mobilization protocol.

Fig. 12

a–e: Results of zone-II flexor tendon injury, treated with primary repair and pulley reconstruction.

Fig. 13

a–g: Steps and results of single stage secondary flexor tendon reconstruction.

Fig. 14

Silastic rods placement for two staged secondary flexor tendon reconstruction.