Muscle injuries

Muscle injuries are defined as damage to the muscle fiber resulting from direct or indirect trauma.

Muscle injuries are caused by:

• Direct Trauma: the force acts on the muscle, compressing it against deeper tissue planes; the resulting damage ranges from a simple contusion to a complete muscle rupture, depending on the severity of the trauma and the muscle's state of contraction. The most frequently affected muscles are the deltoid, quadriceps, and gastrocnemius;
• Indirect Trauma: direct contact with a traumatic force is absent; instead, injuries are linked to sudden passive stretching of the muscle caused by a tensile force applied during the contraction phase, or an overly rapid contraction of the muscle belly starting from a state of complete relaxation. The most frequently affected muscles are the biceps brachii and the hamstrings.

Currently, they are preferably classified according to anatomo-pathological levels of severity:

• Grade I injury: tearing of a few muscle fibers;
• Grade II injury: tearing of a moderate number of muscle fibers;
• Grade III injury: near-total or total tear of the muscle belly.

How do they present clinically?

The symptom of "pain" remains a cardinal element in identifying pathology in individuals engaged in sports activities. The severity of the injury is often accurately described by the athlete: in muscle injuries, the exact point of the muscle tear is easily localized and pinpointed by the patient. In the days following the trauma, however, it becomes less discernible due to the formation of a hematoma. This can be:

• Intramuscular: the hematoma is contained within an intact muscle fascia and clinically manifests with pain and functional impairment;
• Intermuscular: the hematoma spreads into the interfascial and interstitial spaces if the muscle fascia is torn; in this case, there is no increase in pressure within the muscle.

How is a diagnosis made?

The suspicion of an injury is clinical and anamnestic, but confirmation, assessment of extent, and prognosis require instrumental examinations. Ultrasound examination is highly useful, although it is an operator-dependent modality where substantial expertise in sports traumatology is essential to obtain an accurate assessment of the lesion. It should also be noted that the presence of edema or hematoma may lead to an underestimation of the muscle damage. The gold standard examination, however, is MRI, which offers greater sensitivity and specificity. X-rays are useful only in avulsion injuries, where muscle contraction exerts sufficient force to detach the muscle from its bony insertion or origin.

What is the treatment for muscle injuries?

Conservative therapy immediately involves the PRICE protocol: Protect, Rest (rest, potentially protecting the muscle by offloading weight or using braces), Ice (cryotherapy), Compression (compressive bandaging), Elevation (to help reduce the hematoma). After 48 hours, depending on the type of lesion and prognosis, physical therapy rehabilitation may begin. Surgical management is reserved for individuals with high functional demands, complete muscle tears

Dr. Daniele Mazza