Development of a synthetic replacement for flexor tendon pulleys using expanded polytetrafluoroethylene membrane

Reconstruction or replacement of the damaged pulley is a difficult surgical problem because of the need to find suitable biological material, the bulkiness of the repair, and adhesion formation between the pulley and flexor tendons. Therefore, a method was developed to reconstruct the fibro-osseous pulleys with polytetrafluoroethylene (PTFE) membrane. Twenty White Leghorn chickens had the A3 pulley of the long digit excised; this was followed by a standard injury to the flexor profundus tendon. The A3 pulley was then reconstructed with PTFE membrane. In the opposite foot, the A3 pulley was transected laterally, the tendon injured in the same manner, and the native pulley sutured. Seven control chickens had a PTFE pulley reconstruction without tendon injury in one foot and the opposite foot did not undergo surgery. At postoperative days 0, 21, and 35, the animals were killed to evaluate the effectiveness of the PTFE pulleys. Flexor tendon function was assessed by determining the active range of motion of the digit. There was no significant difference between the PTFE pulleys and suture repair of the native pulleys at postoperative days 21 and 35. This indicates that the PTFE pulleys were capable of preventing tendon bow-stringing and did not significantly impair tendon gliding. The breaking strength of the PTFE pulley was less than that of the normal A3 pulleys, but it was sufficient to allow immediate mobilization of the digits postoperatively without fear of pulley rupture. The synthetic PTFE pulley appears to have the potential to function as an effective immediate replacement for the fibro-osseous pulleys.