The Effects of Early Active Motion Rehabilitation after Teno Fixrm Tendon Repair in Zone 11 Flexor Tendon Lacerations of the Hand

The purpose of this study is to evaluate the advantages of an early active motion rehabilitation protocol after flexor tendon repair of the hand with the Teno Fix system. Patients with Zone II flexor tendon lacerations repaired with the Teno Fix system will undergo a rigorous early active motion protocol developed at the New York Orthopedic Hospital, starting post-op day 3. Each patient will be followed and our analysis will focus on range of motion, grip and pinch strength, pain, swelling, and a ftinctional assessment with the DASH (Disabilities of the Arm, Shoulder, and Head) questionnaire. Given that the Teno Fix system offers a stronger and more stable tendon repair construct which allows for earlier mobilization, our hypothesis is that early active motion rehabilitation will lead to a better range of motion of the affected finger while maintaining a low rupture rate. a. Background Repair of flexor tendon injuries of the hand represent a challenge for even the most experienced hand surgeon. Prior to the 1960's, severed tendons were not repaired, instead surgeons chose to graft in tendons as replacements for those injured. Over the last 25 years, an enormous amount of basic research has expanded our knowledge of tendon structure, biomechanics and their response to injury, repair, and rehabilitation, thereby allowing the advent of primary tendon suture methods. The desired outcome is a strong repair that is resistant to rupture and the formation of adhesions. A strong repair permits early mobilization of the digit, a factor that has been correlated with eventual range of motion and functionality. The flexor tendons of the hand are enclosed by a tendon sheath lined by synoviocytes in a parietal and visceral layer that provide a smooth gliding surface for the tendon. Anatomically, the flexor tendons are divided into five zones, with Zone I being the most distal and Zone V the most proximal to the wrist. Overlying the synovial sheath are annular and cruciate pulleys (A I -A5, and C 1 -0) that surround the tendon and bring it next to the phalanges for efficient gliding. Loss of portions of these particular digital pulleys may significantly alter the normal integrated balance between the flexor, intrinsic, and extensor tendons and result in diminished digital motion, power, and flexion contrwtures of the interphalangeal (1P) j ointS . 2 The degree of difficulty in repairing tendon lacerations differs for each of the zones. Zone 11 lacerations are the most difficult to repair because of their involvement of the sheath and pulleys. The essential contribution to tendon healing and gliding is provided by the sheath's vascular and synovial systems. It is therefore important that the surgeon recognizes their integrity during repair. 3 Flexor lacerations in the finger were once found to perform so poorly after primary 4 repair that the Zone H digital sheath was referred to as a surgical no-mans-land. The historically poor results with Zone II repairs has made it the one that most clinical studies focus on. Small commented that tendon repairs in Zone 11 is widely accepted as the yardstick by which 5 techniques of flexor tendon repairs should be assessed. Restoring ftinction after flexor tendon injuries is one of the greatest challenges to hand surgeons and therapists. Historically, repaired flexor tendons were treated with immobilization. Immobilization reduced suture breakage and protected the repair site because tendon healing had already occurred by the time the subject was allowed to move. However, immobilization led to the formation of adhesions that took away all gliding function of the tendon, leading to contractures and functional disability. 6