Sprain, anterior cruciate ligament

• ACL sprain
• ACL partial Tear
• ACL full-thickness tear

• 844.2 Sprain of cruciate ligament of knee
• 717.83 Old disruption of anterior cruciate ligament

• S83.509A Sprain of unspecified cruciate ligament of unspecified knee, initial encounter
• M23.50 Chronic instability of knee, unspecified knee

• 4I: Impaired Joint Mobility, Motor Function, Muscle Performance, and Range of Motion Associated With Bony or Soft Tissue Surgery

Description

• American Medical Association (AMA) has developed standard nomenclature for athletic injuries to ligamentous structures1
  • 1st degree sprain: minor tear of ligament fibers
  • 2nd degree sprain: partial tear of ligament structure
  • 3rd degree sprain: complete tear of ligament

Essentials of Diagnosis

• Clinical diagnosis of a partial tear1
  • Asymmetric Lachman test
  • Negative pivot-shift test
  • KT-1000 arthrometer test ≤ 3mm
  • Confirming arthroscopic observation
• Medial and lateral menisci and medial collateral ligament (MCL) are commonly injured with the ACL2
• History
  • Contact injuries: typically due to application of varus or valgus force to the knee imposing a shear force on the joint
  • Risk for injury increased by2
    • Sudden deceleration
    • Abrupt change in direction
    • Hyperextension of the knee
  • Non-contact injuries (70% of ACL injuries4) typically due to3
    • Deceleration and change in direction (cutting maneuvers)
    • Landing from a jump in full knee extension
    • Pivoting with planted foot and extended knee
    • Hyperextension/flexion of the knee

General Considerations

• It is estimated that more than 250,000 ACL injuries occur in the United States each year2
• 75,000–100,000 ACL reconstructions performed annually5

Demographics

• ACL injuries reported to be 2–9 times more likely in females than in males4,6

Signs and Symptoms

• Feelings of instability in the knee7
• Severe pain at the time of injury 7
• Audible pop at the time of injury7
• Immediate swelling at the time of injury (effusion)

Functional Implications

• Instability of the knee during weight-bearing tasks
• Ambulation distance
• Squatting
• Activities requiring single-leg stance (donning lower extremity clothing)
• Mobility on uneven terrain

Possible Contributing Causes

• Female sex
  • Tendency of females to land from a jump and change direction in a more erect posture, characterized with increased knee and hip extension3,8
  • Tendency of females to land with increased knee valgus3,8
  • Pelvic structure and lower-extremity alignment that result in a varied Q-angle9
  • More narrow intercondylar notch3,9
  • Smaller ACLs3,9
  • Increased estrogen levels and related increase in laxity.3 (This is controversial in research literature.)
• Increased duration of activity and fatigue10
• Athletic activities in dry-weather conditions or playing on artificial turf3
• Increased Body Mass Index (BMI)
• Decreased hamstring strength relative to quadriceps3
• Decreased core ...