Table 1

Classification systems—abbreviated from online supplemental material

Based onAuthorG0G1GIIGIIIGIV
Clinical SignsOdonoghueNo appreciable tissue tearTissue damage and reduced strength of the muscle tendon unitComplete tear of the muscle tendon unit and complete loss of function
RyanTear of a very small number of fibres with Fascia remaining intactTear of a higher no of fibres, fascia still remains intactGreater number of muscle fibres involved. The muscular fascia is at least partially tornCompleted tear of the muscle belly and fascia rupture
WiseMin pain to palpation, localisedSubstantial TOP, poorly localised, 6–12 mm change in circumference, develops 12–24 hours <50% loss of ROM, pain on contraction, loss of power, disturbed gaitIntractable TOP, diffuse, develops in 1 hour, >50% loss ROM, severe pain on contraction, almost complete loss of power, unable to WB
RachunLocalised pain, min swelling, bruising, minor disabilityLocal pain+TOP, moderate bruising+disability, stretching tearing fibres without disruptionSevere pain+swelling disability, severe haematoma, loss of function, palpable defect
ImagingTakebyashiNo abnormalities or diffuse bleeding with or without local fibre rupture (less than 5% of the muscle involved)Focal fibre rupture—more than 5% of the muscle involved, with or without fascial injuryComplete muscle rupture with retraction, fascial injury is present
Peetronslack of US lesionMinimal elongation with less than 5% of muscle involved—hypoechoic areaLesions involving from 5% to 50% of the muscle volume or cross-sectional diameterComplete muscle tears with complete retraction
LeeNormal or focal/general areas of increased echogenicity—perifascial fluidDiscontinuity of muscle fibres in echogenic perimysal strae. Hypervascularity around disrupted muscle fibres. Intramuscular fluid collection, partial detachment of adjacent fascia or aponeurosisComplete myotendinous or tendon-osseous avulsion, complete discontinuity of muscle fibres and associated haematoma. Bell clapper sign
Chan (ISmULT)Normal appearance. Focal or general increased echogenicity with no architectural distortionDiscontinuous muscle fibres. Disruption site is hyper-vasculised and altered in echogenicity. No perimysal striation adjacent to the MTJComplete discontinuity of muscle fibres. Haematoma and retraction of the muscle endsProximal MTJ/muscle proximal/ middle distal/ distal MTJ+intramuscular - myotendionous
Schneider- Kolsky<10° ROM deficit10°–25° ROM deficit>25% ROM deficit
StollerHyperintense oedema+/-haemorrhage with preservation of the muscle morphology. Oedema pattern=interstitial hyperintensity and feathery distribution on FSPD or T2FSE+STIR images hyperintense subcutaneous tissue oedema+intermuscular fluidHyperintense haemorrhage with tearing of up to 50% of muscle fibres. Interstitial hyperintensity with focal hyperintensity representing haemorrhage in the muscle belly+/-intramuscular fluid. Hyperintense focal defect+partial retraction of muscle fibres. associated myotendinous+tendinous injuries. Hyperintensity+interruption +/- widening of muscle - tendon UnitComplete tearing+/-muscle retraction. Hyperintense fluid filled gap+hyperintense on FSPDFSE+STIR. Associated adjacent hyperintense interstitial muscle changes
MixedCohenPoint grading score - Age/muscles/location/ cross sectional area/retraction/ longitudinal axis T2 signal length
MunichIndirectFunctional muscle disorder (consider neuromeningeal) - negative imaging findings
Structural muscle injury: Grading on US/MRI classification System
Direct muscle injury
BAMICNegative imaging findings<10% cross sectional area10%–50% cross sectional areas—5–15 cm>50% cross sectional area >15 xm (tendon >5 cm)Complete rupture
A -Myofascial tear (4 grades) incorporating cranio-caudal length and cross-sectional area for grading—small/moderate/extensive/complete
B - Muscle Tendon Junction tear (4 grades) incorporating cranio-caudal length and cross-sectional area for grading
C -Intra-tendinous tear (3–4 grades) incorporating cranio-caudal length and cross-sectional area for grading
Barcelona - (MLG-R) mechanism of injury/location - muscle/grade/previous injuryNegative MRI but clinical suspicionHyperintense muscle fibre oedema without intramuscular haemorrhage or architectural distortion (fibre architecture and pennation angle preserved). Oedema pattern: interstitial hyperintensity with feathery distribution on FSPD or T2 FSE? STIR imagesHyperintense muscle fibre and/or peritendon oedema with minor muscle fibre architectural distortion (fibre blurring and/or pennation angle distortion) ± minor intermuscular haemorrhage, but no quantifiable gap between fibres. Oedema pattern, same as for grade 1Any quantifiable gap between fibres in craniocaudal or axial planes. Hyperintense focal defect with partial retraction of muscle fibres±intermuscular haemorrhage. The gap between fibres at the injury’s maximal area in an axial plane of the affected muscle belly should be documented. The exact % CSA should be documented as a subindex to the grade
Mechanism of injuryDirect/indirect/stretch or sprint
LocationLocation of lesion—proximal/middle/Distal
Extracellular matrixWhen codifying an intratendon injury or an injury affecting the MTJ or intramuscular tendon showing disruption/retraction or loss of tension exist (gap), a superscript (r) should be added to the grade
SurgicalWoodProximal hamstring attachment rupture based onMTJ versus Tendon injury/avulsion—bony versus tendon/avulsion—partial versus complete/ retraction distance/ sciatic nerve involvement
LampainenNo of tendons involved (1–3)/level of athlete(demand)/level of symptoms (pain+function)
  • BAMIC, British Athletics Muscle Injury Classification; CSA, cross-sectional area; FSE, fast spin echo; FSPD, fat-suppressed proton density; MTJ, musculotendinous junction; ROM, range of motion; STIR, short tau inversion recovery; TOP, tender on palpation; US, ultrasound.