Wrist position and extensor tendon amplitude following repair

After primary repair of severed extensor tendons, various methods are used to limit tendon adhesions and avoid rupture. Early passive digital motion with wrist extension (a "reverse Kleinert" protocol) has been advocated. However, there are no data to support an optimum wrist position or to indicate how much finger motion may safely be permitted. In this study we used eight fresh cadaver limbs to measure extensor tendon gliding in Verdan's zones 3 to 8 when active grip and passive extension were simulated at different wrist positions. We found that if the wrist is extended more than 21 degrees, the extensor tendon glides with little or no tension in zones 5 and 6 throughout full simulated grip to full passive extension, permitting "passive motion" exercises to minimize tendon adhesions without risking rupture. In addition, we found that up to 6.4 mm of tendon can be debrided safely and full grip can still be permitted postoperatively if the wrist is splinted at 45 degrees extension.