Primary Flexor Tendon Repair – Operative Repair, Pulley Management And Rehabilitation

The central tenet of modern flexor tendon surgery is to repair and move divided flexor tendons within a few days of injury. While all flexor tendon surgery is complicated, it is simplest in the newly injured and unscarred digit and the results of correctly rehabilitated primary repairs are likely to be the best attainable. Nevertheless, repair of the divided flexor tendon to achieve normal or near-normal function consistently remains a problem which has not yet been solved. Over and above the actual technical difficulties of repairing tendons, the complications of rupture and adherence of repairs during healing continue to trouble us to an extent that the result of every primary flexor tendon repair still remains uncertain. Healing the flexor tendon takes about 3 months, a period which is sometimes longer than that for which the hand can be kept free of activities or accidents liable to snap the repair. In any healing area, a glue of fibrin-loaded oedema is formed which later converts to scar tissue to achieve a very durable bond. Unfortunately, the body does not limit this healing process to those structures which are injured. Everything in the vicinity becomes involved in the healing process, with the unwanted result that all the tissues become ‘spot-welded’ together by scar adhesions. The devastation this can cause, not only to the flexors but also to other structures of the hand, is the cause of a great deal of the morbidity of hand injury and the source of much of secondary hand surgery. This ‘spot-welding’ can occur anywhere along the length of a flexor tendon but is a particular problem in the digits, where the flexors move within a system as finely bored as the pistons in an engine. For 50 years, most of the drive in this field has been to create a mechanical system which allows us to keep the tendon repair moving after surgery, in the belief that this will prevent adhesions. Early mobilization does not, of course, prevent adhesions entirely, but it does create a form of scarring which allows us to regain much of the range of movement and, sometimes, even return function to normal. Because rupture defeats this aim, there has been a need to create sutures and suture techniques strong enough to allow this movement. Current debate is largely concerned with the fine detail of ‘best’ ways to repair and rehabilitate. An adjunct, or even alternative, to the mechanical approach of strong suture techniques and early mobilization is to try to minimize the formation of adhesions by chemical means. This has been attempted with a variety of drugs, including cytotoxics, hyaluronidase