The Achilles complex is comprised of the tendon of insertion of the gastrocnemius muscle and a common tendon formed from the biceps femoris, semitendinosus, and gracilis muscles.1 The SDFT passes distal to the calcaneus with a fibrous attachment to that bone and is sometimes included as part of the Achilles complex1; however, the tendon does not insert on the calcaneus. Injury to the Achilles complex is typically traumatic in nature, often occurring at or just proximal to insertion on the calcaneus.2 Injuries near the calcaneal attachment typically involve the gastrocnemius or common tendons. Either of the tendons can be involved; however, one study reports gastrocnemius tendon injury alone in 20% of dogs, and injury to all parts of the Achilles complex in 22.2%.3 This study also reported that Labrador retrievers, Doberman pinschers, and border collies were most commonly represented.
When there is significant fiber disruption to the gastrocnemius and common calcaneal tendons, the SDFT will bear increased load with resultant toe curling. There is often a partial plantigrade stance, as the intact SDFT prevents full collapse of the hock to the ground. Radiographs should be performed to rule out other pathologies (eg, fractures), and diagnostic ultrasound may be used to evaluate the architecture of the tendons.
Treatment options include medical and surgical therapies. Nonsurgical options for minor or incomplete tears include exercise restriction, external support, and stimulation of healing with adjunct modalities or regenerative therapies. Therapeutic ultrasound can be used to stimulate healing, reduce inflammation, improve fiber alignment and extensibility, and reduce scar tissue, if present.6 Low-level laser therapy can be used as an adjunct modality to reduce pain and inflammation, and may aid collagen synthesis.7 PRP can be injected directly into the tendon near the lesion to enhance healing by providing autologous growth factors. PRP has been shown to improve tendon healing in animal models.4 It is important to note that NSAIDs should be avoided with the use of PRP as they may affect platelet aggregation.
Surgical management has long been the accepted standard for treatment of severe disruptions or lacerated tendons, and temporary immobilization of the tarsal joint is required to prevent excess load on the repaired tendon postoperatively.2,3 However, surgery is not an option for all patients because of anesthetic risks factors or financial limitations. Deciding between medical and surgical management depends on the degree and chronicity of tendon injury, with chronic cases being more difficult to manage. This case demonstrates successful nonsurgical treatment of a tendon strain. A similar successful case has been reported in the literature.5