Ligament and Tendon Tears
Unfortunately tendon and ligament injuries can be serious enough to not only affect performance but to end a dog’s career. Appropriate treatment in the early stages can restore the most function and strongest repair of the structure is vital in the management of sporting dogs.
Unfortunately, many owners often don’t seek veterinary care in cases of young dogs and only rest them. Their thinking that resolution of the lameness means the problem was completely resolved. However, we now know that in these dogs, the problem becomes chronic and menacing resulting in a reduced performance and often earlier retirement than expected.
Tendons
The main tendon function is to insert muscles onto bones at specific locations, in order to spread the force of a muscle contraction across a joint. Also in addition, tendons may possess some ability to prevent trauma to the muscle by absorbing the forces transmitted through them. Tendons contain 95% type I collagen with less than 5% type III collagen and they are sparsely populated by fibrocytes called tenocytes. The blood supply to tendons is sparse and arises from the myotendinous junction, the epitenon tissue and to a lesser extent from the bone at the tendon’s insertion site. Substantial nutrition is also obtained from the synovial fluid that sheaths tendons.
Strains of tendons are often classified as either acute or chronic and of 3 degrees of severity. The first degree strains cause only a mild lameness with a limited disruption of the tendon fibres, however, intra-tendinous haemorrhage is often present at this stage. Second degree strains then also involve significant disruption of the fibres of the tendon but not all, and there is also soft tissue swelling visible around the injured tendon with an easily identified lameness. Then the third degree strains involve a complete loss of the tendon fibres with a very marked lameness and notable swelling.
Ligaments
Ligaments function to stabilise the joints and to limit the range of motion. Like tendons, ligaments are composed of mostly a type I collagen (approximately 91%) and type III collagen (up to 12%). However, unlike tendons, ligaments do contain more than one cell type and in general they have an increased cell number compared to tendons. The fibrocytes of ligaments are then either spindle shaped or an oval. The blood supply to ligaments is from the periligamentous tissue or to a lesser extent from the ligaments insertion sites on to bone. Significant nutrition may sometimes be obtained from synovial fluid.
Ligament sprains are characterised to tendon strains with 3 stages of injury. First stage sprains involve a disruption of only a few of the fibres of the ligament and joint function remains intact. Second stage sprains involve a significant loss of intact fibres and a loss of normal function of the ligament but mainly, the ligament appears intact. Soft tissue swelling can be visible with second stage sprains. Third stage sprains involve most to complete disruption of the fibres of the ligament and also complete loss of function.
Healing of tendons and ligaments
Inflammation
The inflammation begins with the incursion of leukocytes, the first of which are neutrophils followed by macrophages. A long-lasting inflammatory phase may also negatively affect tendon or ligament healing and repair. Excessive fibrosis will result in disorganised scar formation and a far weaker tendon or ligament repair. Delayed repair of a ruptured tendon or ligament does not necessarily indicate a prolonged inflammatory phase. However, without the presence of an infection or a significant motion, even ruptured ends of tendon or ligaments will undergo repair by production of the epitenon fibroblasts and collagen synthesis (and a thickening) of the tendon ends will occur. If repair is attempted within 3 weeks of the original injury, some investigators have also advocated to not resect the blunt torn ends since it would result in loss of a significant number of proliferating fibroblasts.
In the repair stage, vascular in growth is required to provide oxygen and nutrients to active fibrocytes. Excessive motion during healing will prevent vascular in growth this will cause an increased fibrosis and a decreased primary healing with type I collagen. Gap formation between the tendon or ligament ends also prevents vascular in growth affecting healing and final repair strength.
Repair of tendons and ligaments has conventionally been increased with internal or external adaption of the associated joint in order to protect the repair from too much motion and to prevent the sutures from failing prior to completion of healing. However, prolonged immobilisation of these joints following tendon or ligament repair does cause articular cartilage deterioration in the immobilised joint.
Once the repair stage has been completed, tendons and ligaments need to regain their strength and their purpose to return of the dog to its previous activities as well as prevention of any injury recurrence. This stage does require a slow but necessary use of the tendon or ligament over time. Rehabilitation is designed to allow this process to happen with a steady build up over time and this does prove invaluable to the overall outcome of dogs with tendon or ligament injuries.
Rehabilitation
Low intensity ultrasound therapy has been used in ligament ruptures and has show to help improve the early strength of the injury repair.
Laser therapy has also reduced the time to healing, increase collagen synthesis, and increase tensile strength of healing tissues.
Hydrotherapy has proved to give the best results due to it’s lack of weight put on the joints, ligaments and tendons.
Unfortunately tendon and ligament injuries can be serious enough to not only affect performance but to end a dog’s career. Appropriate treatment in the early stages can restore the most function and strongest repair of the structure is vital in the management of sporting dogs.
Unfortunately, many owners often don’t seek veterinary care in cases of young dogs and only rest them. Their thinking that resolution of the lameness means the problem was completely resolved. However, we now know that in these dogs, the problem becomes chronic and menacing resulting in a reduced performance and often earlier retirement than expected.
Tendons
The main tendon function is to insert muscles onto bones at specific locations, in order to spread the force of a muscle contraction across a joint. Also in addition, tendons may possess some ability to prevent trauma to the muscle by absorbing the forces transmitted through them. Tendons contain 95% type I collagen with less than 5% type III collagen and they are sparsely populated by fibrocytes called tenocytes. The blood supply to tendons is sparse and arises from the myotendinous junction, the epitenon tissue and to a lesser extent from the bone at the tendon’s insertion site. Substantial nutrition is also obtained from the synovial fluid that sheaths tendons.
Strains of tendons are often classified as either acute or chronic and of 3 degrees of severity. The first degree strains cause only a mild lameness with a limited disruption of the tendon fibres, however, intra-tendinous haemorrhage is often present at this stage. Second degree strains then also involve significant disruption of the fibres of the tendon but not all, and there is also soft tissue swelling visible around the injured tendon with an easily identified lameness. Then the third degree strains involve a complete loss of the tendon fibres with a very marked lameness and notable swelling.
Ligaments
Ligaments function to stabilise the joints and to limit the range of motion. Like tendons, ligaments are composed of mostly a type I collagen (approximately 91%) and type III collagen (up to 12%). However, unlike tendons, ligaments do contain more than one cell type and in general they have an increased cell number compared to tendons. The fibrocytes of ligaments are then either spindle shaped or an oval. The blood supply to ligaments is from the periligamentous tissue or to a lesser extent from the ligaments insertion sites on to bone. Significant nutrition may sometimes be obtained from synovial fluid.
Ligament sprains are characterised to tendon strains with 3 stages of injury. First stage sprains involve a disruption of only a few of the fibres of the ligament and joint function remains intact. Second stage sprains involve a significant loss of intact fibres and a loss of normal function of the ligament but mainly, the ligament appears intact. Soft tissue swelling can be visible with second stage sprains. Third stage sprains involve most to complete disruption of the fibres of the ligament and also complete loss of function.
Healing of tendons and ligaments
Inflammation
The inflammation begins with the incursion of leukocytes, the first of which are neutrophils followed by macrophages. A long-lasting inflammatory phase may also negatively affect tendon or ligament healing and repair. Excessive fibrosis will result in disorganised scar formation and a far weaker tendon or ligament repair. Delayed repair of a ruptured tendon or ligament does not necessarily indicate a prolonged inflammatory phase. However, without the presence of an infection or a significant motion, even ruptured ends of tendon or ligaments will undergo repair by production of the epitenon fibroblasts and collagen synthesis (and a thickening) of the tendon ends will occur. If repair is attempted within 3 weeks of the original injury, some investigators have also advocated to not resect the blunt torn ends since it would result in loss of a significant number of proliferating fibroblasts.
In the repair stage, vascular in growth is required to provide oxygen and nutrients to active fibrocytes. Excessive motion during healing will prevent vascular in growth this will cause an increased fibrosis and a decreased primary healing with type I collagen. Gap formation between the tendon or ligament ends also prevents vascular in growth affecting healing and final repair strength.
Repair of tendons and ligaments has conventionally been increased with internal or external adaption of the associated joint in order to protect the repair from too much motion and to prevent the sutures from failing prior to completion of healing. However, prolonged immobilisation of these joints following tendon or ligament repair does cause articular cartilage deterioration in the immobilised joint.
Once the repair stage has been completed, tendons and ligaments need to regain their strength and their purpose to return of the dog to its previous activities as well as prevention of any injury recurrence. This stage does require a slow but necessary use of the tendon or ligament over time. Rehabilitation is designed to allow this process to happen with a steady build up over time and this does prove invaluable to the overall outcome of dogs with tendon or ligament injuries.
Rehabilitation
Low intensity ultrasound therapy has been used in ligament ruptures and has show to help improve the early strength of the injury repair.
Laser therapy has also reduced the time to healing, increase collagen synthesis, and increase tensile strength of healing tissues.
Hydrotherapy has proved to give the best results due to it’s lack of weight put on the joints, ligaments and tendons.
