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The Knee

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					The Knee
Basic Anatomy
                 Basic Anatomy
• Ligaments
  – Anterior Cruciate Ligament (ACL)
      • Prevents femur moving posteriorly during weight bearing
      • Attaches anterior tibia to lateral femur
  – Posterior Cruciate Ligament (PCL)
      • Primary stabilizer & stronger than ACL
      • Attaches posterior femur to anterior tibia
  – Medial Collateral Ligament (MCL)
      • Taut during knee flexion & relaxed in extension
      • Prevents knee from valgus and external rotating forces
      • Attaches medial femur & medial tibia
  – Lateral Collateral Ligament (LCL)
      • Taut during knee extension & relaxed in flexion
      • Attaches to the lateral femur & head of fibula
• Meniscus
  – Medial meniscus: C-shaped fibrocartilage
  – Lateral meniscus: O-shaped fibrocartilage


• Each meniscus is divided into 3
  circumferential zones:
  – Outer zone = good vascular supply
  – Middle zone = minimal vascular supply
  – Innner zone = avascular
Knee Injuries
  Prevention of Knee Injuries
1. Physical conditioning
  •   Muscles surrounding knee joint must be strong
      and flexible
  •   Focus on hamstring, erector spinae, groin,
      quadriceps, gastrocnemius flexibility

2. Rehabilitation and skill development
  •   Strength, balance and technique - sport specific


3. Shoe Type
  •   More and shorter cleats
• MCL sprain

  Cause:
  – valgus force (lateral blow) or severe outward
    twist
  – Greater injury results from medial sprains vs.
    lateral sprains
S&S:
   • Grade I = few ligamentous fibers are torn and stretched;
     joint is stable, little/no swelling, possible joint stiffness &
     point tenderness, full ROM

    • Grade II = complete tear of deep cpsular ligament and
      partial tear of of MCL; slight laxity in full extension, no
      gross instability; no/little swelling; moderate to severe
      joint stiffness with inability to fully extend the knee;
      decrease PROM; medial pain

    • Grade III = complete loss of medial instability; swelling;
      immediate severe pain followed by dull ache; loss of
      motion because effusion and hamstring guarding

Care: RICE; crutches; immobilzer; ROM exercises;
  rehabilitation; hinge brace (grade I, II)
• LCL sprain

   Cause:
   – varus force & internal rotation of the tibia
   – Less prevalent than MCL
S&S:

   • Grade I = joint is stable, little/no swelling, possible joint
     stiffness & point tenderness, full ROM

   • Grade II = slight laxity in full extension, no gross
     instability; no/little swelling; moderate to severe joint
     stiffness with inability to fully extend the knee; decrease
     PROM; lateral pain

   • Grade III = complete loss of lateral instability; swelling;
     immediate severe pain followed by dull ache

Care: RICE; crutches; immobilzer; ROM exercises;rehab;
  hinge brace; surgery controversial
• ACL sprain

  Cause: foot planted, femur externally rotated

  S&S: hear/felt “pop”; immediate disability; rapid
   swelling; intense pain immediately then subsiding

  Care: RICE; crutches; immobilizer; surgery likely; 3-
   5 wks in brace; rehab 4-6 months
• PCL sprain

  – Called the most important ligament in the knee
  – Provides central axis for rotation
  – Provides ~95% restraint of posterior displacement of tibia


  Cause: most at risk when knee is bent hyperflexed knee with
    full weight on anterior aspect of knee and foot plantarflexed;
    rotational force which may affect medial/lateral side of knee

  S&S: pop in back of knee; tenderness and swelling in back of
    knee (popliteal fossa); laxity of ligament

  Care: RICE; Grade 1 & 2 - non-op, rehab focusing on quad
    strengthening; rehabilitation; controversy over surgery
• Meniscus injuries

  Cause: weight bearing combined with
  rotational stress while extending/flexing
  knee

  S&S: may or may not result in effusion
  gradually over 48-72 hrs; joint line pain
  and loss of motion; intermittent
  locking/giving way; pain with squatting

  Care: RICE; recovery depends on
  location of tear; not uncommon to return 6-
  14 days after surgery (menisectomy);
  repaired meniscus may require
  immobilization for 5-6 wks, longer
  recovery
• Bursitis

   Cause: acute, chronic, recurrent;
     prepatellar and deep infrapatellar have
     highest incidence; prepatellar inflamed
     from continued kneeling or falling
     directly on knee; infrapatellar irritated
     from overuse of patellar tendon

   S&S: localized swelling; redness;
     increased temperature; pain due to
     swelling

   Care: eliminating cause; rest; swelling;
     compression; padding; NSAIDs;
     possible aspiration
• Iliotibial band friction syndrome (Runners knee)

   – Overuse condition commonly in runners and cyclists who have
     genu varum and pronated feet
   – Irritation develops at the band’s insertion over the lateral femoral
     condyle causing friciton
Cause: overuse that can be attributed to
 malalignment and structural asymmetries of
 the foot and lower leg;

S&S: tenderness along ITB; little/no swelling;
 pain increases with activity

Care: stretch ITB; massage; foam roller:
 correction of foot and leg alignment problems;
 ice
• Chrondromalacia
  – softening and deterioration of the articular
    cartilage on back of patella
  – Exact cause is unknown
  – Abnormal patellar tracking due to numerous
    factors

  Chondromalacia undergoes 3 stages:

      • Stage 1 = swelling and softening of
        articular cartilage

      • Stage 2 = fissuring of the softened
        articular cartilage

      • Stage 3 = deformation of the surface of
        the articular cartilage caused by
        fragmentation
• Chondromalacia

  S&S: pain anterior knee while walking, running
  up/down stairs or squatting; recurrent swelling around
  kneecap; grating sensation when flex/ext knee

  Care: avoid irritating activities; isometric ex; NSAIDs;
  neoprene sleeve; possible sx
• Patellar tendonitis (jumper’s knee)

   Cause: jumping, running, or kicking repetitively
   – Sudden or repetitive forceful extension of knee may begin an
     inflammatory process that will eventually lead to tendon
     degeneration

   S&S: tenderness; pain;
   – 3 stages:
       • Stage 1 - pain after activity
       • Stage 2 - pain during and after but functional
       • Stage 3 - pain during and prolonged after activity; may progress
         to constant

   Care: avoid irritating activities; RICE; patellar tendon brace;
     NSAIDs; transverse friction massage (TFM)
• Osgood-Schlatter disease

  Cause: adolescent; repeated pull of patellar tendon at the tibial tubercle;
    bony callus forms and tubercle enlarges; usually resolves in late teen
    years

  S&S: repeated irritation causing swelling; hemorrhage, and gradual
    degeneration of tibial tubercle; severe pain when kneeling; jumping
    and running; point tenderness

  Care:  stressful activities; ice before and after activity; isometric
    strengthening of quads and hams
• Patellar dislocation

  Cause: quad muscle pulls in a straight line and patella pulls
  laterally creating a force that may sublux/dislocate patella

  S&S: complete loss of knee function; pain with swelling;
  obvious deformity; possible fracture

  Care: ice; referral with a dislocation -
  spontaneous reduction may occur if
  athlete is able to straighten knee
• Osteochondritits Dissecans

  – A painful condition involving partial or
    complete separation of a piece of articular
    cartilage and subchondral bone
  – Exact cause is unknown
  – Possible causes =
    • direct or indirect trauma
    • skeletal or endocrine abnormalitites
    • prominent tibial spine or part of patella
      impinging on medial femoral condyle
• S&S: achy knee, swells recurrently, may
  catch or lock, possible atrophy of
  quadriceps

• Care: for children, rest and
  immobilization; may take as long as 1yr
  to resolve; surgery = drilling in the area
  to stimulate healing, pinning loose
  fragments, or bone grafting
  (Amare Stoudamire, Greg Oden)

				
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posted:6/9/2012
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