What are the diagnostic criteria for a suspected muscle (musculoskeletal) injury?

From the Guidelines

To diagnose a possible muscle injury, a thorough clinical examination, including assessment of pain, swelling, bruising, limited range of motion, and muscle weakness, is essential, and the use of scoring charts, such as that provided by the UK’s Royal College of Nursing, is recommended 1. When evaluating a patient with a suspected muscle injury, it is crucial to consider the clinical signs and symptoms, including pain, cold, paraesthesia, paralysis, pulselessness, and pallor, although these signs may not be completely reliable in diagnosing acute compartment syndrome (ACS) 1. The diagnosis of ACS remains a controversial area, and several studies have cast doubt on the reliability of diagnosing ACS on clinical signs alone, highlighting the need for a comprehensive assessment 1. Some key points to consider in the diagnosis of muscle injuries include:

• Pain out of proportion to the injury or clinical situation is often reported as being the earliest sign of developing ACS 1
• Pain on passive stretch of the affected muscle compartment is regarded by some as the most sensitive early sign 1
• The presence of both severe pain and pain on passive stretch of the affected muscle compartment gives a positive predictive value of 68% 1
• A predictive value of 93% is found if pain, pain on passive stretch, and paralysis are present, although paralysis is a late clinical sign 1 In terms of management, for mild injuries, the RICE method (Rest, Ice, Compress, and Elevate) may be beneficial, along with over-the-counter pain relievers like ibuprofen or acetaminophen 1. However, if symptoms are severe or do not improve within 1-2 days, medical attention should be sought immediately, and a healthcare provider may perform a physical examination and order imaging tests such as X-rays, ultrasound, or MRI depending on the suspected severity 1. It is also important to note that muscle injuries can occur when fibers are stretched or torn beyond their normal capacity, typically during sudden movements or excessive force, and proper diagnosis is crucial to prevent further damage and prolonged recovery time 1.

From the Research

Diagnosis of Muscle Injury

To diagnose a possible muscle injury, the following steps can be taken:

• History and physical examination are essential in making a diagnosis, as most cases can be identified through these methods 2
• Diagnostic imaging, such as ultrasound or magnetic resonance imaging (MRI), can be used to confirm the diagnosis and assess the severity of the injury 3, 4
• Classification of muscle injuries can be done based on anatomy, biomechanics, and imaging features, and a recently reported new classification system can be used 5
• Physical examination tests, such as the cross-body sit-up test and the presence of an adductor contracture, can be used to assist in the diagnosis of core muscle injury, but should be used in conjunction with diagnostic imaging 6

Diagnostic Imaging

Diagnostic imaging plays a crucial role in assessing the severity of muscle injuries and excluding important complications:

• Ultrasound examination is essential for a correct assessment of the severity of the injury and can be used to exclude important complications 3
• MRI provides better anatomical definition and can be used to confirm the diagnosis and assess the severity of the injury 6, 4
• Ultrasound is dynamic and cheap, but examiner dependent, while MRI provides more detailed images 4

Classification and Treatment

Muscle injuries can be classified into different grades, and treatment options vary depending on the severity of the injury:

• The current classification divides muscle injuries into mild, moderate, and severe, based on signs and symptoms such as edema, loss of function, and complete rupture 4
• Treatment options include protection, rest, optimal use of the affected limb, and cryotherapy, as well as nonsteroidal anti-inflammatory drugs (NSAIDs), ultrasound therapy, strengthening, and stretching 2, 4
• Surgery has precise indications, such as hematoma drainage and muscle-tendon reinsertion and reinforcement 4