Rehabilitation of Equine Tendon Injuries

Introduction
Successful rehabilitation of a damaged tendon is thought to require a carefully controlled loading environment to stimulate the formation of functional repair tissue and to minimise restrictive adhesion formation. The most damaging aspect of exercise is considered to be high impact loading, seen with high-speed exercise. Therefore rehabilitation should be undertaken in an environment which is capable of limiting loading. At present, rehabilitation programmes are largely empirical and there is still the need for a rehabilitation protocol backed by evidence of efficacy. However, in the absence of such data, the following is an ‘idealised’ rehabilitation programme based on what we understand of the reparative processes in tendon and a consensus view from a group of equine orthopaedic specialists (Smith and McIlwraith, 2012).

Empirical ‘idealised’ rehabilitation programme for over-strain flexor tendon injury
Clinical overstrain injury results in disruption of the tendon matrix and haemorrhage. This usually provokes a short-lived marked inflammatory response which removes the damaged tendon tissue. The signs of inflammation (heat, pain (lameness), swelling (oedema)) are associated with considerable hyperaemia, invasion of white blood cells (neutrophils followed by macrophages and monocytes) and the release of proteolytic enzymes. Rapid and aggressive anti-inflammatory treatment (especially using physical treatments such as ice, cold hosing and compression) will help minimise the excessive effects of this natural debridement. Exercise at this stage is contra-indicated as it may cause more damage and drive inflammation. The horse should therefore be given box-rest and, if fetlock support has been compromised with severe injury, the fetlock can be further supported by splints or casts. Controlled passive mobilisation (non-weight-bearing) can be helpful to dissipate inflammatory fluid and maintain a full range of motion.  [...]