Strain, hamstring

• Pulled hamstring

• 848.9 Unspecified site of sprain and strain

• T14.9 Dislocation, sprain, and strain of unspecified body region

Description

• Stretch injury to biceps femoris or semimembranosus resulting in disruption of muscular or musculotendinous units
  • Grade I: mild
  • Grade II: moderate
  • Grader III: severe to complete tear or rupture

Essentials of Diagnosis

• Diagnosis made with patient history and clinical findings or with imaging
• Pain with resistance
• Location of Lesion May Influence Prognosis

General Considerations

• Mechanisms of injury1
  • Deceleration during swing phase while running
    • Typically occurs during high-speed running
    • Involves intramuscular tendon or aponeurosis of biceps femoris (long head), semitendinosus (secondary injury)
  • Excessive stretch while dancing or kicking
    • Typically during extreme hip flexion with full knee extension
    • Injury at proximal tendon of semimembranosus

Demographics

• Previous hamstring injury is a strong predictor of recurrence
• Athletes in high-speed-demand sports (e.g., football, track, rugby, soccer)
• Athletes in sports/competition involving kicking or extreme hip flexion and knee extension (e.g., dancing, water-skiing)

Signs and Symptoms

• Acute-onset pain at proximal hamstring during high-speed running, often with audible pop, typically early or late in athletic event
• Pain at ischial tuberosity with sitting
• Decreased range of motion (ROM) in knee and hip
• Decreased strength with knee flexion and hip extension
• Tenderness to palpation (possible palpable lesion) at proximal tendon or musculotendinous junction
• Tenderness may occur along muscle belly proximal to ischial tuberosity

Functional Implications

• Inability to run or sprint
• Inability to sit without limitation from pain
• Inability to flex hip with knee fully extended

Possible Contributing Causes

• Previous history of hamstring injury
• Explosion activity without proper warm-up
• Muscle imbalance between quadriceps and hamstring

Differential Diagnosis

• Adverse neural tension
• Adductor muscle strain
• Avulsion fractures at ischial tuberosity
• Lumbar radiculopathy
• Sacroiliac dysfunction
• Sciatica

Imaging

• MRI for soft tissue

• MRI can reveal area of fluid accumulation and location of lesion

Medication

• NSAIDs

Medical Procedures

• Surgery to repair grade-III strain or avulsion

• To hospital for imaging (MRI)
• Surgery (if grade-III strain)

• Inability to run or sprint
• Inability to sit without limitation from pain
• Inability to flex hip with knee fully extended

• Straight leg raise limited secondary to muscle tightness
• Pain with resistance

• Take caution initially not to overstretch and eccentrically load injured muscle
• Early and continued incorporation of core stability and eccentric hamstring loading progressing to full length
• Rehabilitation for grade-I and grade-II strains
  • Phase 1, 1 to 5 days post-injury ...