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Acute Hamstring Injury

From WikiSM
(Redirected from Hamstring Tear)

Other Names

  • Hamstring strain injuries (HSI)
  • Hamstring tear
  • Acute Hamstring Injury
  • Hamstring Strain
  • Hamstring Partial Tear

Background

  • This page refers to acute Hamstring injuries (HSI) including strains, partial and complete tears

History

  • Needs to be updated

Epidemiology

  • General
    • Injury rates have not declined in recent decades despite the well know problem of HSI
    • Most common cause of lost playing time in Australian football
    • Most common cause of prolonged absence (>28) days from training, playing soccer
    • Average number of days lost ranges from 8 to 25, depending on severity and location[1]
    • Majority of studies on hamstring injuries in athletes report highest incidence between age 18 and 30
  • Financial Implications
    • HSI cost in excess of £74.4 million in English premier and football league clubs during the 1999–2000 season[2]
    • In elite Australian footballers, HSI cost $AU1.5 million in the 2009 season[3]
  • Incidence of HSI
    • Up to 29% of all injuries in athletes[4]
    • Track and field: estimated to account for 26% of track and field injuries[5]
    • Australian football: 13-15%
    • Soccer: 12-14%[6]
    • American football: 12%[7]
    • Rugby: 15%[8]
    • Over a 10 year span among NFL football players (1998-2007), incidence of HSI was second only to knee sprains[9]
  • Recurrence
    • Up to 1/3 of HSI recur, greatest risk is in the first 2 weeks following return to sport[10]
    • 27% of all HSIs in the Australian Football League are recurrences of previous injuries; however, recent evidence suggests this is trending downwards[11]
    • American Football: 32%
    • Rugby: 21%
    • Soccer: 16%

Introduction

The biceps femoris is most commonly injured[12]
Illustration of the hamstring muscles[13]

General

  • Hamstring injuries are one of the most common non-contact injuries in sports
  • They are the most common in Australian football, American football, rugby, soccer and sprinting[14]
  • Characterized by acute onset of pain of the posterior thigh
  • Injuries range from microscopic tearing and pain (grade I) to full muscle rupture and complete loss of function (grade III)
  • Most commonly occur at myotendinous junction

Etiology

  • Running accounts for the majority of HSI[15]
    • Can also occur due to kicking, tackling, cutting, slow-speed stretching
    • Typically a non-contact injury
  • Biomechanics
    • Hamstrings active during the entire gait cycle, peaking during terminal swing and early stance[16]
    • Hip is flexed, knee is extended
    • Terminal swing: eccentric contraction to decelerate extending knee and flexing hip, teach maximum length
    • Early stance: concentric contraction while in contact with ground, possibly still some eccentric component
    • Also can be related to sudden takeoff phase of running
  • Eccentric contraction
    • Occurs primarily during terminal swing, to a lesser extent during early stance
    • Primary suspect for high rate of HSI
    • Terminal swing phase most hazardous as muscle-tendon units at their longest length
    • Muscle length during eccentric contraction reaches 110% for Biceps Femoris, 107.5% for Semimembranosus and 108.2% for Semitendinosus[17]
  • Muscle strain
    • Magnitude of stress or strain on muscle contributes to HSI
    • Unclear if eccentric load or muscle strain is primary etiology, likely mixed
  • Other considerations
    • Unclear if due to accumulated microscopic damage or single event exceeding mechanical limits of the muscle[18]

Pediatric Considerations

  • Ischial apophysis
    • Weakest link in the kinetic chain
    • Ossifies around age 15-17, fuses around age 19-25

Anatomy of the Hamstrings

    • Muscles: Biceps Femoris, Semimembranosus, Semitendinosus
    • Muscle group is biarticular, actions are to flex knee and extend hip
    • SemiM and SemiT provide some internal rotation while the Biceps Femoris provides some lateral rotation
  • The Biceps Femoris is the most commonly injured muscle
    • The myotendinous junction or muscle-tendon junction is the most common site of disruption
    • Undergoes the greatest stretch during terminal swing
  • During gait/ running
    • Normal gait: responsible for hip extension, knee flexion with concentric contraction
    • While running: also assists in deceleration, hip flexion and knee extension with eccentric contraction

Associated Pathology


Risk Factors

Non-modifiable risk factors

Modifiable

  • Weak hamstring muscles[24]
  • Asymmetric hamstring strength[25]
  • Low hamstrings:quadriceps ratio (hamstrings weak relative to quads)[26]
  • Greater knee angle at peak concentric knee flexion[27]
  • Fatigue during a match[28]
  • Inadequate warmup
  • High training volume

Lack of flexibility

  • This is controversial
  • Some studies have shown that increased flexibility reduces risk[29]
  • Several prospective studies found no relationship between hamstring flexibility and future HSI[30]
  • In one study of elite Australian Footballers, increased flexibility actually increased risk of HSI[19]

Sports

Theoretical/ Proposed


Differential Diagnosis

Hamstring injury vs referred pain

Differential Diagnosis Hip Pain

Differential Diagnosis Thigh Pain


Clinical appearance of diffuse posterior thigh ecchymosis with a proximal myotendinous hamstring injury[38]

Clinical Features

History

  • Onset is typically sudden with a sharp pain, patients may endorse a "pop"
  • Pain ranges from minimal to severe depending on degree
  • Pain is posterior, may be worse with sitting
  • Patient may have trouble running or even walking
  • In patients with distal hamstring injuries, athletes can usually report a specific moment when they had knee hyperextension, sense of instability[39]

Physical Exam: Physical Exam Hip

  • Examine patient in prone position if possible
  • Goal is to determine location, severity of injury
  • Hip and knee: strength and flexibility are both diminished
  • Athlete should have point tenderness at the site of injury
  • Bruising, swelling may be present with more serve injuries or avulsion injuries
  • Defect or mass may be palpable in the setting of complete tear, typically middle 1/3 posterior thigh
  • Often have "stiff legged" gait due to guarding against hip flexion, knee extension

Special Tests


Evaluation

A 21-year-old sprinter presenting with a left hamstring injury, clinically diagnosed as a grade 1 injury. a Axial FS PD-w TSE image shows an area of hyperintensity with a feathery appearance (arrow), consistent with a strain of the long head of the biceps femoris (L). A[40]
Typical short axis US findings in acute hamstring strains. Muscle (A), musculotendinous junction (B), and tendon (C) injuries. White dotted circles indicate injured areas.[41]

Radiographs

Ultrasound

  • General
    • Excellent diagnostic tool
    • Initial imaging modality of choice
    • Sonopalpation often correlates to pathologic findings
    • Very useful to monitor interval healing
    • As sensitive as MRI for acute hamstring injuries[42]
  • Findings
    • Hyperechoic muscle and tendon
    • May see hypoechoic fluid (blood)
    • May see interruptions in myotendinous architecture
    • Bony avulsion with displacement of hyperechoic bony cortex

MRI

  • General
    • Often reserved for more severe injuries where rupture is suspected
    • In chronic cases, used to evaluate sciatic nerve as well
  • Findings
    • Increased signal intensity (T2 weighted)
    • May show avulsion of ischial tuberosity
  • May be superior to US in the following cases
    • Evaluating injuries to deep portions of the muscles[43]
    • When a previous hamstring injury is present, as residual scarring can be misinterpreted on an US image as an acute injury[44]
    • Better quantifying the size of injury (length, cross sectional area)

Classification

Figure 2. Intratendinous. British Athletics Muscle Injury Classification system: letter classification system based on the anatomical site of muscle injury. (A) Myofascial, (B) musculotendinous, (C) intratendinous.[45]
  • Grade I
    • Mild
    • Damage: minimal
    • MRI: T2 hyperintense signal about a tendon or muscle without fiber disruption
  • Grade II
    • Moderate
    • Damage:
    • MRI: T2 hyperintense signal around and within a tendon/muscle with fiber disruption less than half the tendon/muscle width
  • Grade III
    • Severe
    • Damage: complete tear or rupture
    • MRI: Tendon/muscle fiber disruption greater than half its tendon/muscle width

Management

(A) 11+ (Russian) eccentric hamstring exercise and (B) demonstrating proper lumbopelvic control[45]
Nordic hamstring eccentric exercise: (A) starting position, (B) eccentrically controlling descent with proper lumbopelvic control, and (C) lowering upper body to the ground.[45]

Goals

  • Return athlete to his or her prior level of function
  • Minimize risk for reinjury

Prevention

  • Nordic Hamstring Exercise (NHE)
    • Description: athlete in kneeling position, gradually lowers upper body toward ground with extension at knee with eccentric contraction of hamstrings to slow decent
    • Shown to increase hamstring torque, shift torque-joint angle to longer muscle lengths[46]
    • Two studies with low compliance among amateur Australian Footballers[47], and professional soccer players[48] failed to reduce the risk
    • Elite soccer players who incorporated NHE into pre- and per-season conditioning demonstrated a 65% reduction in rates of HSI and decreased severity of HSI[49]
  • Flywheel Training Ergometer
    • Designed to augment eccentric torque during leg curl
    • Shown to increase eccentric hamstring strength, reduce HSI rates[50]
    • Small RCT also showed reduction of HSI[51]
  • Strength Imbalance Correction
    • Large cohort study (n=462) showed risk reduction of HSI by detecting and correcting isokinetic strength imbalances[52]
  • Flexibility
    • When compared to controls, prescribing contract-relax flexibility training during warm up did not reduce rate of HSI[53]
    • An unsupervised 16 week warm-up and cool-down stretching program among recreational runners did not reduce the risk of HSI compared to control[54]

Nonoperative

  • Approach of choice in most cases including
    • Single tendon tears
    • Multi-tendon tears with <2 cm retraction
    • Rupture at myotendinous junction
    • Individuals with low activity levels, significant comorbidities
  • Relative rest
  • Medications
  • Physical Therapy
    • See: protocolized rehabilitation below
  • Corticosteroid Injection
    • Controversial, not currently recommended, data lacking on proven benefit
    • Corticosteroids known to be myotoxic and tenotoxic[55]
    • Levine et al found no determinantal effects, may accelerate recovery time for return to play[56]
  • Platelet Rich Plasma
    • Limited retrospective studies show faster healing, less swelling[57]
    • Rossi showed a 5 day faster RTP with PRP but no difference in rate of recurrence[58]
    • Sheth performed a systematic review of PRP on muscle injuries and found 6 day decrease in RTP across all injuries, however no difference for hamstring injuries[59]
  • Consider the follow soft tissue therapies to consider, no evidence to recommend for or against
    • Electrophysical agents
  • Evidence shows no benefit
  • Conflicting Evidence
    • Massage Therapy has mixed evidence on hamstring muscle activity and flexibility, no evidence regarding any effect on healing or recovery[61]

Operative

  • Indications[62]
    • 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
  • Technique
    • Tendon repair
    • ORIF if significant displacement of bony avulsion (>2 cm)

Rehab and Return to Play

Rehabilitation Protocol for Grade 2 Hamstring Injuries[63]
Supine bent knee bridge walk-out: start in (A) supine bridge position and (B and C) perform a progressive movement of feet away from hips, while maintaining bridge position

Rehabilitation

  • Goals
    • Focus on remodeling with eccentric strength training
    • Increased range of motion, flexibility

Proposed Rehab Program

  • General
    • From Heiderscheit et al[64]
    • Targeting Grade I and II hamstring injuries
    • See reference for better description of individual exercises
  • Phase 1
    • Duration 1-5 days immediately post injury
    • Protection: avoid excessive stretching, pain can define ROM
    • Analgesia: Ice, NSAIDS, consider crutches
    • Exercise: promote neuromuscular control within a protected range of motion, thereby minimizing the risk of damage to the remodeling muscle
    • Progression criteria
      • 1: normal walking stride without pain
      • 2: very low-speed jogging without pain
      • 3: Pain-free isometric contraction against submaximal (50%-70%) resistance during prone knee flexion (90°) manual strength test
  • Phase 2
    • Protection: return to full range of motion unless weakness is present
    • Analgesia: continue ice after therapy, discontinue NSAIDs if possible
    • Exercise: promote a gradual increase in hamstring lengthening
    • Progression criteria
      • 1: full strength (5/5) without pain during a 1-repetition maximum effort isometric manual muscle test
      • 2: forward and backward jogging at 50% maximum speed without pain
  • Phase 3
    • Protection: No restriction to ROM, sprinting and explosiveness avoided until RTP criteria met
    • Analgesia: Ice after rehabilitation
    • Exercise: agility, and sport-specific drills should be emphasized that involve quick direction changes and technique training, respectively
    • Return to Sport Criteria:
      • Remains challenging and important area of future research
      • Athlete must be able perform full ROM, strength, and functional abilities without complaints of pain or stiffness
      • Strength: 4 consecutive reps of max effort manual strength test

Return to Play

  • Contributors to re-injury risk[65]
    • Persistent weakness in the injured muscle
    • Reduced extensibility of the musculotendon unit due to residual scar tissue
    • (Mal)adaptive changes in the biomechanics and motor patterns of sporting movements following the original injury

Prognosis and Complications

A prognostication algorithm for RTP following acute type I hamstring injuries developed from the simplified MRI‐based 4‐grade injury model[66]

Prognosis

  • Physical Exam
    • For injuries involving the intramuscular tendon, clinical exam is as predictable of rehabilitation duration as findings on MRI[67], however this same study found this was not true for proximal tendon
  • MRI Findings predicting longer recovery
    • Injury involving a proximal free tendon
    • Proximity of the injury to the ischial tuberosity
    • Increased length, cross-sectional area of injury
    • Useful to estimate time away from sport, but not risk of re-injury[64]
  • Location
    • Shorter recovery time at the intramuscular tendon, despite more pain, when compared to the longer recovery more proximal to ischial tuberosity[68]
  • Consequences
    • Associated with significant time lost from training, competition[69]
    • May result in financial losses among professional athletes[2]
    • Diminished athletic performance[3]
    • Performance is reduced upon return following HSI

Complications

  • Recurrent hamstring strain
  • Peroneal Nerve Injury
  • Sciatic Nerve Injury
  • Hamstring Syndrome
  • Ischial Tuberosity Nonunion
  • Chronic pain
  • Inability to return to sport

See Also

Internal

External


References

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Created by:
John Kiel on 5 July 2019 08:46:46
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5 August 2025 16:13:42
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