Hamstring Strain / Tear
synonyms: Hamstring Pull, hamstring tear, hamstring strain, ischial tuberosity fracture, ischial tuberosity avulsion fracture,
Hamstring Tear ICD-9
- 843.9 (unspecified sprain and strain of hip and thigh)
Hamstring Tear Etiology / Epidemiology / Natural History
- Injury usually at musculotendinous junction
- Complete avulsions are associated with water skiing (Orava S, Am J Sports Med 23:702;1995).
- Proximal rupture occurs from sudden hip flexion/knee extension causing hamstring contraction.
- Ischial avulsion fractures generally occur from forced hyperflexion (eccentric contraction) of the hip while the knee is fully extended.
Hamstring Tear Anatomy
- Hamstrings = Biceps(long head)[tibial n] and Biceps(short head[peroneal n]), Semitendinosus[tibial n], Semimembranosus[tibial n].
- All except short head originate from ischial tuberosity.
- Separate muscle become distinguishable 5-10cm form tuberosity.
- Complete avulsions generaly occur at the ishial tuberosity.
- Ischial apophysis is relatively weak in adolescences making ischail apophyseal avulsion fractures more common in adolescences.
- Ischail apophyseal secondary ossification center appears in early puberty and does not fuse until late adolescences. (Gidwani S, BMJ 2004;329:99).
Hamstring Tear Clinical Evaluation
- Audible pop followed by pain during strenuous athletic activity or when fatigued.
- May have palpable defect, palpate entire muscle belly with knee flexed 90 degrees
- Proximal avulsions are generally associated with sharp severe pain in the posterior thigh with subsequent difficulty ambulating. May have pain with sitting due to ishial tuberosity avulsion site.
- Generally have stiff-legged gait.
- Documument Sciatic nerve function. Document EHL, TA and peroneal function.
Hamstring Tear Xray / Diagnositc Tests
- Xray indicated if ischial avulsion is suspected. Rarely helpful otherwise.
- MRI helpful for proximal ruptures. Demonstrates amount of retraction and number of tendons involved. Feathery increased signal on T2 images indicates musculotendinous injury or muscular stain (Hamstring). Fatty infiltrate in the muscle indicates chronic injury.
Hamstring Tear Classification / Treatment
- Mild(grade I)=disruption of <5% of structural integrity,
- Moderate (gradeII),
- Severe grade (III)=complete rupture
- Treatment= RICE=rest, ice, compression, elevation; gentle stretching, gradual return to activities
- Single tendon proximal avulsion: MRI demonstrates retraction <2cm. Treatment = non-op. Generally return to full activities at 6-8 weeks.
- Acute Complete promimal hamstring avulsion from its ischial origin: MRI demonstrates >2cm retraction. Leads to significant long-term disability and should be repaired acutely. Generally repaired with suture anchors into the ischial origin. (Klingele KE, AJSM 2002;30:742). For repair technique see: Cohen S, JAAOS 2007;15:350.
- Chronic Complete hamstring avulsions: function generally improved with reconstruction. Sciatic nerve neurolysis is typically required. Achilles tendon allograft should be available if direct repair is not possible after mobilization. Achilles bone block is attached to the ischium withan interference screw; the allograft is then suture to the native tissues. (Larson, C)
- Surgery: only indicated for proximal or distal tendon avulsions
- See also: Ischial Tuberosity Avulsion Fracture.
Hamstring Tear Associated Injuries / Differential Diagnosis
Complications of Hamstring repair
- Failed repair / rerupture
- sciatic neuralgia / palsy
- incisional pain
Hamstring Tear Follow-up Care
- Nonsurgical treatment of complete proximal ruptures leads to: knee flexion weakness, mild hip extension weakness, pain with sitting, hamstring syndrome (Puranen J, AJSM 1988;16:517).
Hamstring Tear Review References
- Clanton and Coupe, Hamstring strains in athletes: diagnosis and treatment, JAAOS, 6(4): 237-248, 1998
- Cohen S, JAAOS 2007;15:350