Acute Sports Injuries - LIGAMENTS

Ligaments typically span joints to connect articulating bones, and present as either discrete extra-articular structures or thickenings of the joint capsule. Their structure consists of tightly packed bundles of collagen arranged nearly in parallel along the longitudinal axis of the ligament, helping them to resist tensile loads. Ligaments function to provide passive stability and guide what directions of motion are available at a joint. When force is applied to a joint that attempts to move the bones in a direction they aren't designed to move, passive tension rises in the ligaments on the side of the joint being gapped open. When the load is sufficient, and dynamic joint stabilisation afforded by the active and neural subsystems is insufficient, collagen fibres within ligaments begin to yield, resulting in acute ligament injury (commonly referred to as a 'sprain').

Ligament sprains range in severity from mild injuries (tearing only a few fibres) to severe (complete tears of the ligament where ligament continuity and its stabilising role is completely lost.) Ligament sprains are classified into 3 grades:

Initial management of acute ligament sprains consists of first aid techniques to minimise bleeding and swelling.. For grade I and II sprains, subsequent treatment aims to promote tissue healing, prevent joint stiffness, protect against further damage and strengthen muscle to provide dynamic joint stability. Return to sport usually takes place before tissue level healing is complete, with healing of collagen in a partial ligament tear often taking several months.. Earlier return to sport is achieved by the use of taping or bracing to help protect against re-injury. Rehabilitation (especially neuromuscular training) should continue in some form following return to sport as injury risk is heightened.

The treatment of a grade III sprain may be either conservative or surgical. For example, a torn medial collateral ligament of the knee or a torn lateral ligament of the ankle can be treated conservatively with full or partial immobilisation. Alternatively, the 2 ends of a torn ligament can be surgically reattached and the joint then fully or partially immobilised for approx. 6 weeks. In some cases (e.g anterior cruciate ligament rupture), torn ligament tissue is not amenable to primary repair and so may require surgical ligament reconstruction.

Over the past few decades, there have been increasing efforts to develop tissue engineering strategies that encourage ligament regeneration as opposed to repair, so that the final result matches that of a native ligament. Strategies have included the use of growth factors, cell-based therapies, gene transfer and therapy, and the use of scaffolding materials of varying origin. These approaches have shown promise in preclinical studies, but translation to clinical populations remains lacking and is required before clinical utility.

REFERENCES

Brukner, P., 2012. Brukner & Khan's clinical sports medicine. North Ryde: McGraw-Hill.