Hamstring Tears

The hamstrings run from the ischial tuberosity of the pelvis to the knee. The medial hamstrings comprise the semimembranosus and semitendinosus muscles, the lateral hamstrings the two heads of biceps femoris.

Semimembranosis

Semitendinosis

Biceps femoris short head

Biceps femoris long head

Incidence of all muscle strains in the body:

  • Hamstrings     25%

  • Calf         19%

  • Quadriceps    17%

  • Lumbar    9%

  • Adductor     8%

 

Variety of hamstring injuries, such as contusion, strain, laceration or even complete rupture.

Pathophysiology of injury:

  • Biceps most active during take off and support phase

  • Medial hamstrings most active during late swing phase

  • Both usually injured with ballistic eccentric contraction with knee extended & hip flexed (Kicking, hurdling, jumping etc)

History:

  • Acute pain on activity

  • felt (or heard) a sudden “pop”

  • Unable to run


Examination:

  • Prone with knee flexed

  • Point tenderness worse on stretching

  • Occasionally palpable defect (fills with haematoma after a day or two)

 

Graded by severity:

  • Grade I: mild pain, minimal spasm, loss of 20 degrees extension, no defect

  • Grade II: Moderate pain & spasm, bruising & swelling, loss of 20 to 45 degrees of extension

  • Grade III: Complete rupture, palpable defect early on, inability to tense muscle, severe pain, swelling & bruising

 

Investigations:

  • Ultrasound for grade II & III

 

Treatment:

  • More bleeding = delayed healing, more scar tissue &possible myositis ossificans

  • Rest, ice, NSAIDs in acute phase

  • Rehabilitation after 5 to 7 days stretching, strengthening, muscle balance

  • Avoid early return 

  • Endurance training & good warm up