To describe techniques of venting major pulleys – A2 and A4 pulley during primary repair.

During primary repair of the zone II flexor tendon, major pulleys often present as an obstacle of passing the tendon and restrict tendon gliding. Those pulleys can be vented under following conditions:

– other pulleys are intact;

– tendon injury and sheath opening is limited (<2cm sheath incision), not extensive;

– tendon repair is smooth and gliding is indeed prevented by those pulleys.

The A4 pulley can be entirely vented and the A2 pulley can be vented over 1/2 to 2/3 of its length. My method of venting is to cut along its volar midline, and shortening or partial resecting the pulleys may become necessary, often in the cases of delayed primary repair when the pulleys collapse. Recognition of structures of the pulleys is important. The A2 pulley is about 1.5–2cm in the long finger and the A4 is much narrower, of about 0.5cm, but both are rigid and restrictive. Other methods include oblique venting and lateral venting. After pulley venting, the tendon gliding should be confirmed to be smooth.

I have performed this kind of venting for many years, and have not seen clinically significant bowstringing and the venting has been safe.

Venting of the pulleys may be an important part of zone II primary flexor tendon surgery. Though this is against the traditional way of treating the pulleys, the venting is safe when done properly, and may be a key to improve function of tendon repair.