Early Protected Weightbearing for Acute Ruptures of the Achilles Tendon: Do Commonly Used Orthoses Produce the Required Equinus?

Abstract

Conservative “functional” management of acute Achilles tendon ruptures has become increasingly popular. Critical to this is the use of the walking orthosis, which positions the ankle in equinus to allow for early weightbearing. Our aim was to test whether 2 common orthoses achieved a satisfactory equinus position. A total of 11 sequentially treated Achilles tendon ruptures were assigned to either a fixed angle walking boot with wedges (FAWW) or an adjustable external equinus-corrected brace (EEB). The lateral radiographs of the cast immobilized tendons showed a mean tibiotalar angle (TTA) of 56° (range 54° to 57°) and a mean tibio-first metatarsal angle (1MTA) of 74° (range 62° to 85°). The FAWW resulted in a mean TTA of 28° (range 15° to 35°) and 1MTA of 37° (range 30° to 45°). The EEB resulted in a TTA of 48° (range 43° to 45°) and 1MTA of 54° (range 47° to 57°). Ankle equinus was significantly greater with the EEB than with the FAWW (p < .05) and similar to that with an equinus cast. The use of wedges produced an equinus appearance through the midfoot but not at the ankle. We express caution in the use of the FAWW because it is unlikely to achieve sufficient ankle equinus to shorten the Achilles tendon.