Updated: 1/26/2023

Hamstring Injuries

Review Topic
Videos / Pods
    • Hamstring injuries most commonly occur at the myotendinous junction in running athletes as a result of sudden hip flexion and knee extension.
    • Diagnosis can be made clinically with ecchymosis in the posterior thigh, tenderness over the hamstring muscles and avoidance of knee extension. Diagnosis can be confirmed with MRI.
    • Treatment is generally conservative with rest, ice, and protected weightbearing. Multiple tendon involvement or bony avulsion may require operative management. 
  • Epidemiology
    • Incidence
      • make up 30% of new lower extremity injuries in athletes
        • annual increase of 4% noted in soccer players over last ~15 years
    • Demographics
      • most commonly seen in rapid acceleration sports
        • soccer, track and field, and football
    • Anatomic location
      • myotendinous junction
        • is the most common site of rupture in adults
        • often occurs during sprinting
      • avulsion of ischial tuberosity
        • less common
        • seen in skeletally immature
          • 10% of all pelvis avulsion fractures in the skeletally immature
        • seen in water skiers
    • Risk factors
      • previous hamstring injury (increases risk of reinjury by factor of 6)
        • previous injury leads to formation of weakened scar tissue lowering threshold to recurrent injury
      • inadequate warm-up
      • strength imbalance (hamstring to quadriceps ratio < 0.6)
      • hamstring strength difference with contralateral leg (> 10-15%)
      • reduced hip extension
      • leg-length differences (shorter leg has tighter hamstrings)
  • Etiology
    • Pathophysiology
      • Mechanism of injury
        • intramuscular and musculotendinous injuries
          • most often occur during sudden takeoff phase of running
        • proximal hamstring avulsions
          • occurs as a result of hip flexion and knee extension
            • eccentric contraction of hamstring at the end of swing phase when muscle fibers are at maximal elongation.
      • Pathobiology
        • satellite cell plays a role in muscle healing following muscle injury
  • Anatomy
    • Hamstrings
      • 4 muscles
        • semimembranosus
        • semitendinosus
        • biceps femoris
          • long head
          • short head
      • origin
        • all originate on ischial tuberosity except short head
          • short head originates from linea aspera on femur
          • semimembranosus has most lateral attachment
      • insertion
        • semimembranosus inserts on posterior aspect of medial tibial condyle
        • semitendinosus inserts on superomedial tibial shaft within the pes anserine
        • biceps femoris long head inserts on fibular head
        • biceps femoris short head has many insertions (fibular head, biceps femoris long head, lateral knee capsule)
      • innervation
        • tibial branch of sciatic nerve: semimembranosus, semitendinosus, long head of biceps femoris
        • common peroneal branch of sciatic nerve: short head of biceps femoris
      • blood supply
        • inferior gluteal artery and profunda femoral artery
      • other
        • hamstring origin on ischial tuberosity is ~6 cm proximal to inferior border of overlying gluteus maximus
        • sciatic nerve is 1.2 cm from lateral bony aspect of hamstring origin
    • Biomechanics
      • cross and act upon 2 joints: the hip and knee
        • except short head which only crosses the knee joint
  • Classification
      • Hamstring Tear MRI Classification 
      • Grade 1
      • T2 hyperintense signal about a tendon or muscle without fiber disruption
      • Grade 2
      • T2 hyperintense signal around and within a tendon/muscle with fiber disruption less than half the tendon/muscle width
      • Grade 3
      • Tendon/muscle fiber disruption greater than half its tendon/muscle width
  • Presentation
    • History
      • sudden pain in the posterior thigh during running, kicking or jumping activity
      • occasionally a "pop" felt
    • Symptoms
      • common symptoms
        • posterior thigh pain
        • hamstring tightness
        • pain with sitting
          • proximal avulsions
    • Physical exam
      • inspection
        • ecchymosis in posterior thigh
          • most common seen in proximal avulsions or high grade myotendinous tears
      • palpation
        • may have palpable mass in middle 1/3 of posterior thigh (myotendinous rupture)
        • tenderness to palpation
          • ischial tuberosity
          • myotendinous junction
          • distal tendinous insertions
      • gait
        • "stiff-legged" gait (avoiding knee and hip flexion)
      • motion
        • increased popliteal angle
          • flexing hip to 90 degrees with knee flexed to 90 degrees, and then slowly extending knee
            • knee angle where posterior thigh pain is felt is compared to uninjured leg
      • motor
        • weak hamstring strength
          • while prone, knee flexion strength measured with knee at 90 degrees flexion
            • compared to contralateral side
      • neurovascular
        • may have peroneal nerve weakness (foot drop etc.)
      • provocative tests
        • the following tests are positive for hamstring tendinopathy or strain if the patient feels pain
          • Puranen-Orava Test
            • heel is placed on an elevated surface and patient reaches for toes
            • sensitivity 0.76, specificity 0.82
          • bent-knee stretch test
            • with patient supine, hip and knee are maximally flexed and knee is slowly passively extended
            • sensitivity 0.84, specificity 0.87
          • modified bent-knee stretch test
            • with patient supine, hip and knee are maximally flexed and then the knee is rapidly fully extended
            • sensitivity 0.89, specificity 0.91
  • Imaging
    • Radiographs
      • recommended views
        • AP pelvis, AP and lateral femur
      • findings
        • may show bony avulsion off of ischial tuberosity
    • MRI
      • indications
        • evaluation of the insertion site and quantify number of involved tendons and degree of tendon retraction
        • evaluate the sciatic nerve location (in chronic cases)
      • findings
        • may show avulsion off ischial tuberosity
        • tendinopathy will be seen as increased signal intensity in T1-weighted images
        • partial tears will have increased signal intensity on T2-weighted images
  • Diagnosis
    • Clinical and MRI
      • diagnosis confirmed by history, physical exam, and MRI
  • Treatment
    • Nonoperative
      • rest, ice, NSAIDS, protected weightbearing for 4 weeks followed by stretching and strengthening
        • indications
          • most hamstring injuries
          • all single tendon tears
          • 2 tendon tears with < 2 cm retraction
          • rupture at myotendinous junction
          • less active patients and those with significant medical comorbidities
        • outcomes
          • take up to 6 weeks to heal
          • only return when strength is 90% of contralateral side to avoid further injury
      • PRP injection
        • indications
          • acute hamstring strains in high level athletes
        • outcomes
          • some low level studies have shown earlier return to play by 3-5 days in NFL players
    • Operative
      • tendon repair
        • indications
          • proximal avulsion ruptures
          • partial avulsion that has failed nonoperative management for 6 months (persistent symptoms)
          • 2 tendons with at least > 2 cm retraction in young, active patients
          • 3 tendon tears
        • outcomes
          • 80% return to preinjury level/sports at 6 months
          • high level of complications with surgery, up to 23% in some studies
            • higher complication rate with repair of chronic cases compared to acute (< 6 weeks)
      • ORIF
        • indications
          • bony avulsions with > 2 cm displacement
          • chronic symptomatic bony avulsions
        • outcomes
          • union rates vary across studies
  • Techniques
    • rest, ice, NSAIDS, protected weightbearing for 4 weeks followed by stretching and strengthening
      • modalities that have shown benefit
        • massage, ultrasound, electrical stimulation
      • protected weightbearing
        • most studies state 4 weeks, but should be extended if patient still significantly symptomatic
      • stretching and strengthening
        • as symptoms resolve, abdominal, hip and quadriceps should be added to hamstring strengthening program to prevent reinjury
        • hamstrings should be strengthened to correct any hamstring-quadriceps strength imbalance
      • injury prevention
        • Nordic hamstring exercise
          • athlete kneels while heels are held on ground by an assistant; the athlete than leans forward until he is prone and then returns to original upright position
          • shown to reduce injuries by 50-70% in some studies
        • isolated targeting of specific hamstring muscles
          • long head of the biceps femoris and semimembranosus are more active during hip extension
          • semitendinosus and short head of biceps femoris more active during knee flexion
    • PRP injection
      • recommendation is to administer within 24-48 hours of acute injury
      • ultrasound-guided injection recommended
    • tendon repair
      • positioning
        • prone with leg free so knee can be flexed to relieve hamstring tension.
      • approach
        • transverse incision over gluteal crease
          • can be extended distally in "T" configuration for large retracted tear
        • hamstring fascia typically intact
          • vertical fascial incision will often lead to encountering a hematoma or fluid collection
        • sciatic nerve runs on average 1.2 cm lateral to the most lateral aspect of ischial tuberosity
      • technique
        • ischium insertion site should be scraped with a periosteal elevator or curette to improve healing environment
          • avoid burr to decreased risk to sciatic nerve
        • repair to the ischial tuberosity with the use of multiple suture anchors (4-6 suture anchors) with the knee flexed
          • allograft bridge may be needed in severely chronic cases when hamstrings are not able to be re-approximated to tuberosity
            • Achilles allograft has shown comparable results to acute repairs in small studies.
      • post-operative protocol
        • patients typically made partial weight bearing for 4-6 weeks with knee flexed to 40 degrees
          • knee brace or hip brace can be used
    • ORIF
      • approach
        • as above
      • technique
        • direct reduction followed by fixation with multiple partially or fully threaded screws with washers
          • can supplement with suture anchors and/or interference screws
  • Complications
    • Recurrence 
      • incidence
        • most common complication
          • 12-31% of patients sustain repeat injury
      • risk factors
        • hamstring weakness
        • hamstring-quad imbalance
        • premature return to activity
    • Peroneal nerve injury
      • risk factors
        • distal non-insertional hamstring injuries
      • treatment
        • usually self-resolving
    • Sciatic nerve injury
      • incidence
        • 8% of surgical cases
      • risk factors
        • chronic cases with scarring of the nerve to the hamstring
      • treatment
        • nerve exploration
    • Hamstring syndrome
      • localized posterior buttock and ischial tuberosity pain secondary to nonoperatively treated hamstring avulsion injuries
      • treatment
        • surgical release and sciatic nerve decompression
    • Ischial tuberosity nonunion
      • risk factors
        • bony avulsion fractures > 2 cm treated nonoperatively
      • treatment
        • ORIF +/- bone graft
  • Prognosis
    • Can be very unpredictable injuries with variable return to sport
      • Overall 84% of patients recover pre-injury strength and 89% recover pre-injury endurance
    • Poor prognostic variables
      • severely retracted tears
      • chronic tears with scarring to sciatic nerve
Flashcards (78)
1 of 78
Questions (5)
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK

(OBQ12.152) Which of the following most accurately describes the primary role of satellite cells?

QID: 4512

To act as an intermediary in the cell-signalling pathway for bone remodeling



To regenerate skeletal muscle after muscle injury



To regenerate periosteum after periosteal damage in a child



To bind chemotherapeutic ligands in the treatment of lymphoma of bone



To express high amounts of sonic hedgehog surface protein



L 4 C

Select Answer to see Preferred Response

(OBQ07.217) Concomitant flexion of the hip and extension of the knee is most likely to result in an injury to which structure?

QID: 878




Rectus femoris



Adductor magnus



Biceps Femoris



Tensor fascia lata



L 1 D

Select Answer to see Preferred Response

(OBQ07.175) A 15-year-old boy sustains the injury seen in Figure A while running the hurdles. The same mechanism in an adult athlete would most likely result in which of the following injuries?

QID: 836

Hamstring myotendinous junction rupture



Pelvic ramus fracture



Hamstring muscle belly rupture



Hamstring tendinous insertion rupture



Sports hernia



L 1 D

Select Answer to see Preferred Response

Evidence (23)
Private Note