What is the recommended size and number of layers for a backslab (plaster or fiberglass cast) for an average weight woman with an Achilles tendon rupture?

From the Guidelines

For an average weight woman with an Achilles tendon rupture, a backslab cast should typically consist of 8-10 layers of plaster or 4-6 layers of fiberglass material, as this provides sufficient support while immobilizing the ankle in an optimal position for initial Achilles tendon healing 1. The backslab should extend from just below the knee to beyond the toes, with the foot positioned in 20-30 degrees of plantar flexion (pointing downward).

• The width of the backslab should be approximately 4-6 inches (10-15 cm), ensuring adequate coverage of the posterior aspect of the leg and foot.
• Fiberglass is generally preferred over plaster as it's lighter, more durable, and water-resistant, though plaster may be used initially due to its better moldability.
• The backslab should be secured with an elastic bandage wrapped circumferentially around the leg. This immobilization typically remains in place for 2-3 weeks before transitioning to a more definitive treatment, such as a full cast or walking boot with gradually decreasing plantar flexion. The multiple layers provide necessary strength while preventing excessive weight that could cause discomfort or skin complications during the initial healing phase. It's worth noting that the most recent and highest quality study, 1, does not provide specific guidance on the size and number of layers for a backslab for an Achilles tendon rupture, but the recommended construction is based on general principles of immobilization and support for ankle injuries.

From the Research

Backslab Size and Layers for Achilles Tendon Rupture

• The recommended size and number of layers for a backslab (plaster or fiberglass cast) for an average weight woman with an Achilles tendon rupture is not explicitly stated in the provided studies 2, 3, 4, 5, 6.
• However, the studies suggest that the rehabilitation protocol for Achilles tendon rupture typically involves immobilization in a plantarflexed position, followed by gradual weight-bearing and range of motion exercises 2, 3, 4.
• A systematic review of postoperative rehabilitation protocols for Achilles tendon repair found that early postoperative weight-bearing with less rigid immobilization appears to accelerate short-term functional recovery 3.
• The "GAIT" study group recommends an average postoperative non-weight-bearing period of 2.3 weeks, with the foot in plantarflexion for the first 4 weeks, and avoiding range of motion exercises beyond neutral 4.
• There is no specific guidance on the size and number of layers for a backslab in the provided studies, suggesting that this information may not be readily available in the existing literature 2, 3, 4, 5, 6.

Rehabilitation Protocols

• The rehabilitation protocols for Achilles tendon rupture vary widely between studies, with different approaches to weight-bearing, range of motion, and physiotherapy 2, 3, 4.
• A systematic review of the literature found that there is no consensus on the optimal postoperative management of Achilles tendon rupture, and further studies are needed to determine the long-term effects of accelerated physical therapy and return-to-play protocols 3.
• The "GAIT" study group provides a consensus statement on rehabilitation protocols, including the use of a 1/8th-1/4th inch heel cushion in daily shoes after 8 weeks, and the return to sports based on heel raise repetitions 4.