Muscle Injuries Classifications

Abstract

The study of the muscle injuries classification is going through a period of strong scientific interest, the testimony of this is the numerous studies recently appeared in the literature concerning this topic. Furthermore, some fundamental aspects of the problem, as for example the objective classification of the injury, its proximity with the tendon structures, and some nosologic clinical framework (as for example the fascial lesions) must still be perfectly clarified, especially as a function of their strong value in prognostic terms. Furthermore, the study and the classification of muscle injuries suffers from a double contradiction, the first one is of clinical type, while the second one is of diagnostic type. Concerning the first point, the contradiction is represented by the fact that, while the muscle injuries represent the most common trauma in sports, their specific management is still based on few high quality studies and is often based on empiricism (Mason et al. 2012; Hamilton et al. 2015). Concerning the second point, the contradiction (that is not less serious than the first one) is represented by the incoherence that arises from the fact that, despite the imaging techniques have been greatly improved over the last few years, and that this has substantially refined the sensitivity and specificity of the means of investigation, the muscle injuries classification is still based on an “ictu oculi” evaluation and staging that is strongly dependent from the operator. For this reason, this situation is conditioned by an intrinsic variability index that, from a scientific point of view, is difficult to accept. It is clear that this last aspect vanishes, if not totally, at least in good part, the great technological improvement of the imaging. Finally, from a practical point of view we must underline that a correct theoretical classification collides with the objective difficulty represented by its practical applicability in a real radiological context. For these reasons it is important to remember that a correct classification should respect the following points:

Appendices

Indirect Muscle Injuries (indMIs)

Classification	Delayed onset muscle soreness (DOMS)	Fatigue-induced muscular disorder (FIMD)	Grade 0 lesion (inMI 0°)	Grade I lesion (indMI I°)	Grade II lesion (indMI II°)	Grade III lesion (indMI III°)
Definition	Substructural lesion	Substructural lesion	Substructural lesion	Structural lesion	Structural lesion	Structural lesion
History	The subject has no memory of the injury event	The subject has no memory of the injury event	The subject has memory of the injury event	The subject has memory of the injury event. He/she usually fails to complete the activity	The subject has memory of the injury event. He/she fails to complete the activity	The subject has memory of the injury event. He/she fails to complete the activity
Symptoms	Pain is often perceived even at rest. In most of the cases pain is bilateral	Pain is not perceived at rest but only during activity. The pain is unilateral	Pain is not perceived at rest but only during activity	Normally, the pain is not perceived at rest but only during activity	Pain is often perceived even at rest. The sport activity is impossible	Pain is perceived even at rest. The sport activity is impossible
Symptoms onset	24 h after the triggering event	Cramping onset during sport activity or the symptoms are referred at the end of the sport activity	During sport activity in acute manner and linked to a specific event	During sport activity in acute manner and linked to a specific event	During sport activity in acute manner and linked to a specific event	During sport activity in acute manner and linked to a specific event
Anatomical site	Totality of the muscle	A more or less extended muscle area but in any case less than the extension of the entire muscular belly	A localized and reproducible muscle point	A well localized and well-reproducible muscle point	A well localized and perfectly reproducible muscle point	A well localized and perfectly reproducible muscle point
Clinical evaluation	Stiffness at palpation and to the pressure over the total muscle belly defense reaction to the stretching	Stiffness area at the palpation. Defense reaction to the stretching	Pain is well localized and induced by palpation and elongation. Often the pain is induced by eccentric contraction	Pain well localized and induced by palpation, elongation, and eccentric contraction. Often the pain is also induced by concentric contraction	Pain is well localized and induced by palpation, elongation, eccentric and concentric contraction. Often the pain is also induced by isometric contraction	Pain is well localized and induced by palpation, elongation, eccentric, concentric, and isometric contraction
US	Negative	Negative	Negative	Positive: The extension of the injury has a diameter less than 5 mm	Positive: The extension of the injury has a diameter greater than 5 mm that can arrive just to 85% of the CSA of the muscle	Positive the extension of the injury is > 85% of CSA
MRI	Negative	Negative	Muscular edema without blood extravasation	Positive: The extension of the injury as a diameter less than 5 mm	Positive: The extension of the injury has a diameter greater than 5 mm that can arrive just to 85% of the CSA of the muscle	Positive the extension of the injury is > 85% of CSA
Classification in US	DOMS	FIMD	Not possible	indMI I°	indMI I° (di tipo a, b, c)	LMin III°
Classification in RM	DOMS	DMIF	indMI 0°	indMI I°	indMI II° (A, B, or C type)	indMI III°
Prognosis (with optimal treatment)	48–72 h	3–5 days	About 8 days	About 15 days	About 20 days for an indMI II° A, about 40 days for an indMI II° B and about 60 days for an indMI II° C	Between 60 and 90 days

Direct Muscle Injuries (dirMIs)

Classification	Minor direct MI (dirMI GMi)	Moderate direct MI (dirMI GMo)	Severe direct MI (dirMI GS)
Functional limitation	More than half of the total range of motion is allowed	Less than half, but more than 1/3 of the total range of motion is allowed	Less than 1/3 of the total range of motion is allowed
Definition	Structural lesion	Structural lesion	Structural lesion
Symptoms	Pain during the muscle palpation	Pain both during the muscle palpation and the movement	Pain also at rest
Symptoms onset	Immediately at the time of injury or after a few minutes	Immediately at the time of injury or after a few minutes	Immediately
Clinical evaluation	Stiffness area at palpation. Defense reaction to stretching. In the case of intermuscular injury the hematoma may not be visible	Stiffness area at palpation. Defense reaction to stretching. In the case of intermuscular injury often the hematoma may be visible	Stiffness area at palpation. Defense reaction to stretching. In the case of intermuscular injury the hematoma is visible
US	Positive: Circumscribed hematoma	Positive: Diffused hematoma	Positive: Diffused hematoma and crushing of muscle fibers
MRI	Positive: Circumscribed hematoma	Positive: Diffused hematoma	Positive: Diffused hematoma and crushing of muscle fibers
US classification	dirMI GMi	dirMI GMo	dirMI GS
MRI classification	dirMI GMi	dirMI GMo	dirMI GS
Prognosis (with optimal treatment)	3–10 days	Between 10 and 50 days	Between 50 and 70 days

Imaging Card (MRI-US)

Mrs/Mr: _______________________________________

Age: ______________________________________

Sport activity (and eventually the role): _______________________________

Evaluation date: ___________________________

Note: concerning the MRI examination, the radiologist is entitled to choose from the following list the most appropriate images for the composition of the MRI investigation protocol.

Test	Result	Note
In the coronal T1 MRI sequences how much is the maximum extension of the injury zone?	Axis 1: Axis 2:
In the sagittal T1 MRI sequences how much is the maximum extension of the injury zone?	Axis 1: Axis 2:
In the axial T1 MRI sequences how much is the maximum extension of the injury zone?	Axis 1: Axis 2:
In the coronal T2 MRI sequences how much is the maximum extension of the injury zone?	Axis 1: Axis 2:
In the sagittal T2 MRI sequences how much is the maximum extension of the injury zone?	Axis1: Axis 2:
In the axial T2 MRI sequences how much is the maximum extension of the injury zone?	Axis 1: Axis 2:
In the coronal STIR MRI sequences how much is the maximum extension of the injury zone?	Axis 1: Axis 2:
In the sagittal STIR MRI sequences how much is the maximum extension of the injury zone?	Axis 1: Axis 2:
In the axial STIR MRI sequences how much is the maximum extension of the injury zone?	Axis 1: Axis 2:
In the transversal US image how much is the maximum extension of the injury zone?	Axis 1: Axis 2:
In the longitudinal US image how much is the maximum extension of the injury zone?	Axis 1: Axis 2:
Injury anatomical site	Indicate the muscle
Injury anatomical site	Choose between: Proximal Central Distal
Distance from the proximal free tendon, distal free tendon or central tendon
Distance from the “raphe” in the case of semimembranosus injury

Return to Play Clinical Test Schedule (Parameters Used to Access to the Return to Play Field Test Schedule)

Test	Score/result	Note
Has the subject pain during active knee extension test?	YES/NOT
In case of YES to the previous question to indicate the VAS score	To choose a score between 0 and 10
Has the subject pain during passive stretch test?	YES/NOT
In case of YES to the previous question to indicate the VAS score	To choose a score between 0 and 10
The range of motion is similar between two legs	YES/NOT
In case of NOT to the previous question to indicate the degrees of difference
Into the isokinetic test performed at 60°/s. The value is less than 15% in comparison to the contralateral limb?a	YES/NOT
In case of YES to the previous question indicate the value
Into the isokinetic test performed at 300°/s. The value is less than 15% in comparison to the contralateral limb?a	YES/NOT
In case of YES to the previous question indicate the value
Into the eccentric test performed at 60°/s. The value is less than 15% in comparison to the contralateral limb?a	YES/NOT
In case of YES to the previous question indicate the value
During the eccentric test the peak of force is it produced at the same articular angle?a	YES/NOT
In case of NOT to the previous question indicate the value of the two different angles

1. ^aIf during the test the subject refers a VAS more than 3, the test must be considered as negative

Return to Play Field Test Schedule

Test	Score/result	Note
Into the braking test 30 m sprint over 8 m the recorded value is it less than 15 W kg−1?a	YES/NOT
In case of YES to the previous question indicate the value
Into the braking test 30 m sprint over 6 m the recorded value is it less than 15 W kg−1?a	YES/NOT
In case of YES to the previous question indicate the value
Into the braking test 30 m sprint over 4 m the recorded value is it less than 15 W kg−1?a	YES/NOT
In case of YES to the previous question indicate the value
Retro run test over 20 ma	YES/NOT
Illinois agility test a	YES/NOT
Shooting side to side testa	YES/NOT

1. ^aIn the case of VAS more than 3 also if the subject is arrived to perform the test the result is calculated as NOT