Acute Sports Injuries - FIBROCARTILAGE

ACUTE TEAR

Fibrocartilage consists of a mixture of fibrous and cartilaginous tissue in varying proportions, which provide it with both toughness and elasticity. Fibrocartilage forms a range of structures in different joints with varying functions, but its main roles are to enhance joint stability, contribute to shock absorption and promote joint lubrication. Examples of fibrocartilage structures include the knee menisci, glenoid and acetabular labrums, triangular fibrocartilage complex (TFCC) at the radio-carpal joint, volar plates of the digits, and articular discs within the acromioclavicular and sternoclavicular joints.

Given the mostly mechanical roles of the fibrocartilage structures in enhancing joint congruency and distributing stresses, they are at risk of acute injury when excessive forces are introduced. The knee menisci are at risk when rotation is superimposed onto a flexed and loaded knee, and a fall onto an outstretched hand can acutely injure the TFCC at the radio-carpal joint. Simultaneous injury with associated joint structures (e.g. ligaments and joint capsule) is common due to their close anatomical and mechanical relationships. It is common for a knee meniscus and anterior cruciate ligament to be simultaneously injured as they share a common mechanism of injury (i.e. rotating on a flexed and loaded knee).

Signs and symptoms of acute fibrocartilage injury are region - and injury - specific, but generally include pain and swelling in the affected joint combined with joint clicking, catching or locking. This can contribute to reflex muscle inhibition and the sensation of the joint 'giving way' during load bearing.

Management of acute fibrocartilage injuries depends on the type, size and location of the damage. Surgical options include repair, removal and replacement of the damaged fibrocartilaginous structure. Surgery is an option for individuals who have failed to respond to conservative management, but is also often used as a first-line management approach, particularly for injuries in areas with limited healing potential. These include the avascular zones within the inner two-thirds of the menisci and the central region of the TFCC.

HERNIATION OF NUCLEUS PULPOSUS FROM INTERVERTEBRAL DISC

Herniation of the nucleus pulposus in athletes most commonly occurs secondary to the damage accumulation within the dic in response to repetitive flexion and/or rotational loading. The vast majority of disc herniations are overuse injuries, despite the onset of symptoms often occurring relatively spontaneously and in response to an apparently trivial loading event. It is possible to acutely prolapse or herniate an otherwise healthy intervertebral disc with sufficient compressive and flexion force. This can occur during contact sports when the spine is axially loaded whilst in a flexed position , such as when driven into the ground when being tackled. The disc may protrude or herniate radially beyond the usual margins of the annulus fibrosis or herniate through the vertebral body endplate into the vertebral body to form a Schmorl's node.

REFERENCES

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