Closing the gap on Achilles tendon rupture: A cadaveric study quantifying the tendon apposition achieved with commonly used immobilisation practices

The relative benefits of surgical and conservative treatment of Achilles tendon rupture are widely debated. With modern conservative management protocols, the re-rupture risk appears to fall to one similar to surgical repair with negligible loss of function. Conservative management typically employs a period of time in an equinus cast with sequential ankle dorsiflexion in a functional orthosis. The optimal duration of immobilisation and rate of dorsiflexion is unknown. We aimed to quantify the change in Achilles tendon approximation achieved in common immobilisation techniques to assist the design of rehabilitation protocols.Twelve fresh-frozen cadaveric specimens had 2.5 cm of Achilles tendon excised. The gap between the tendon ends were measured via windowed full equinus casts and compared with functional boots with successively removed heel wedges.The greatest tendon apposition was achieved with the equinus cast. Each wedge removed decreased the reapproximation by approximately 5 mm.This paper supports the early use of maximal equinus casting in early management of acute Achilles tendon ruptures.