Cartilage Problems in Sports

Types of Cartilage

Hyaline Cartilage

  • Functions to decrease joint friction and distribute load across the joint; also referred to as articular cartilage

  • Composition: Water (65%–80%), collagen (10%–20%, predominantly type II), proteoglycans (10%–15%, aggrecan is most responsible for the hydrophilic property), and chondrocytes (5%) ( Fig. 57.1 )

    Figure 57.1, Composition and structure of articular cartilage.

  • Viability: Articular cartilage is avascular, and chondrocytes are nourished via diffusion from synovial fluid

  • Structure: Organized into three primary layers—superficial, middle, and deep; the tidemark separates these layers from the calcified cartilage and subchondral bone (see Fig. 57.1 )

  • Location: Articular surfaces, ribs, and nasal septum


  • Functions in direct tendon and ligament insertions and helps in the healing of articular cartilage lesions. Less durable than hyaline cartilage.

  • Composition: Primarily type I collagen, extracellular matrix, chondrocytes, water

  • Location: Tendon/ligament junction with bone, menisci, and annulus fibrosis of the intervertebral disc

Elastic Cartilage

  • Strong but flexible cartilage that can withstand repeated bending

  • Composition: Primarily type II collagen, elastin fiber network, extracellular matrix, chondrocytes, water

  • Locations: Pinnae of ear, epiglottis

Types of Cartilage Issues in the Athlete

Articular Cartilage Injuries

  • Can be caused by either acute injury or a more chronic, avascular process

  • Deep lesions: Cross the tidemark and penetrate the subchondral bone; vascularity from the subchondral bone promotes fibrocartilage healing (type I collagen) rather than the preferred articular cartilage

  • Superficial lesions: Do not penetrate the subchondral bone and therefore have no intrinsic healing potential secondary to the avascular nature of articular cartilage

  • Healing is enhanced by motion of the involved joint to encourage diffusion of nutrients and to trigger mechanoreceptors in the cartilage that promote matrix synthesis

Apophyseal Injuries

  • An apophysis is a normal developmental outgrowth of cartilage adjacent to the physis that serves as the attachment site for major tendons and ligaments

  • Is a separate secondary ossification center from the epiphysis and does not contribute to longitudinal growth of the bone

  • Fuses with the bone later as skeletal maturity is reached

  • Traction apophysitis: Repetitive microtrauma caused by the pull of attached tendons; results in partial avulsion and inflammation of the apophysis; common in active children and adolescents; excessive force may result in avulsion fracture of the apophysis

  • Osteochondrosis: General term for disorders affecting one or more ossification centers in children; encompasses conditions such as traction apophysitis and avascular necrosis

History and Physical Examination


  • A detailed description of the onset of symptoms, mechanism of injury, duration and quality of symptoms, and any relieving or exacerbating factors should be obtained

  • Symptoms may include pain with activity, swelling of the affected joint, and mechanical complaints, such as clicking and locking

  • Overuse injuries typically have an insidious onset with no identifiable precipitating injury

Physical Examination

  • Few, if any, physical examination tests are highly specific for the evaluation of articular cartilage injury

  • A complete examination of the involved joint should be conducted, including range of motion, assessment of pain with resisted motion, focal tenderness, and presence of an effusion

  • Apophyseal injuries can present with pain upon palpation of the affected apophysis and pain with resisted motion of the muscle or ligament that attaches at the apophysis

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