Table 4 Definitions of the nine most common EILP conditions

Chronic exertional compartment syndrome

… is defined as increased pressure in the lower leg compartment causing severe pain, tightness, and paraesthesia which in severe cases that would occur every time sufferers exercise for at least 6–12 months. The anterior compartment is most affected and symptoms usually bilateral, affecting the ability to do competitive sports. It is more common in young males. Symptoms may persist for months to years and usually build during activity until they must stop, pain then settle with rest, recurring on return to activity. The mechanism is tightness in the affected compartment due to an increase in intramuscular pressure, resulting in a lack of perfusion and altered physiology. CECS diagnosis is confirmed by measurement of dynamic intracompartment pressure. SPNES and MTSS need to be excluded.

22 definitions reported in 59 (37%) relevant publications

2 common partial definitions, first reported in [147, 148]

Medial tibial stress syndrome

… is defined as periostitis causing diffuse pain for months to years at the distal posteromedial border of the tibia, which can be unilateral or bilateral, and lead to compromised ability to exercise. It is more common in young active individuals involved in endurance activity (runners, dancers, and military recruits), and can last for a few hours to days per episode. The mechanism is subcutaneous periostitis associated with altered biomechanics of the lower limb, training errors and increased training intensity. MTSS diagnosis is confirmed by clinical history, site of pain, palpation, MRI scan and bone scan. Stress fracture and CECS of the deep posterior compartment need to be excluded.

11 definitions reported in 21 (52%) relevant publications

2 common definitions, first reported in [132, 146]

Tibial stress fracture

… is defined as cortical or full bone fracture causing localised excruciating pain both at rest and with weight-bearing activity with nocturnal pain for days to few weeks. This occurs on a daily basis until it heals, typically at the middle to lower one-third of the tibia most commonly but can occur anywhere. The acute pain can cause gross disability and usually affect young age group 10–30 years of age and it heals in a minimum of 6–8 weeks with immobilisation. The mechanism is an imbalance between osteoblast and osteoclast activity leading to bone breakage due to overtraining, overuse, and repeated overloading. Tibial stress fracture diagnosis is confirmed by localised tenderness, plus positive hop and/or fulcrum test. Bone tumours and frank fracture need to be excluded.

10 definitions reported in 31 (32%) relevant publications

2 common definitions, first reported in [48, 149]

Superficial peroneal nerve entrapment syndrome

… is defined as mechanical compression of the superficial peroneal nerve causing moderate to severe pain, paraesthesia, numbness, and the feeling of a ‘restless leg’ for few months to years at unilateral anterior compartment of the leg. It is more common in young active adults and each episode can last for minutes to an hour. The symptoms occur with activity and are relieved with a variable period of rest. The mechanism is scarring/entrapment around the opening of the fascia where the nerve becomes a cutaneous sensory nerve supplying the dorsum of the foot. SPNES diagnosis is confirmed by diagnostic local anaesthetic test. CECS needs to be excluded.

3 definitions reported in 15 (20%) relevant publications

2 common definitions, first reported in [150, 151]

Myofascial tear

… is defined as a single event causing a tear within the myofascial causing pain with activity as the main symptom and can be severely disabling. Located at the interface between the aponeurosis and the fibre or muscle fasciculus (and its corresponding perimysium).

It is more common in young active adults and can be acute or chronic. In chronic cases, pain occurs with activity and is relieved with rest. The mechanism is the tendon or aponeurosis affected either focally by small muscle fibre tears or by major tears that produce a muscle gap but not a tendinous gap. Myofascial tears diagnosis is confirmed by dynamic ultrasound or, more reliably for deep tears, MRI. Muscle tears, haematoma, radiculopathy, and sural nerve entrapment syndrome need to be excluded.

0 definition reported in 3 (0%) relevant publications

1 common definition, first reported in [152, 153]

Lumbar radiculopathy

… is defined as mechanical compression of a nerve root at the level of the spinal cord as it exits the foramen or lateral recess causing sharp pain … radiates down the legs, paraesthesia, numbness, spontaneous cramp, lack of power, fatigue, and tiredness in one or both legs during activity and at rest for months to years. It usually affects the posterior dermatomes and myotomes of the legs but can occur in other areas leading to restricted movement, disturbed sleep, and altered ability to exercise. It is more common in males 30–50 years old. The mechanism is mechanical compression of a nerve root at the level of the spinal cord as it exits the foramen or lateral recess. Lumbar radiculopathy diagnosis is confirmed by lumbar-sacral MRI scan and sometimes EMG/nerve conduction study. Gluteal and piriformis syndromes, myopathy, and in some cases unusual and uncommon CECS and PAES need to be excluded.

3 definitions reported in 7 (42%) relevant publications

1 common definition, first reported in [154]

Popliteal artery entrapment syndrome

… is defined as arterial insufficiency in the affected limb which arises with entrapment of the artery, commonly giving leg symptoms with exertion causes pain, poikilothermia along with tightness, paraesthesia, and numbness can also occur for weeks to three months at the superficial posterior compartment, and it is usually unilateral, leading to intermittent claudication and temperature changes. It is more common in young active runners and each episode can lasts for few minutes. The mechanism is an abnormal relationship between the popliteal artery and the surrounding myofascial structures in the popliteal fossa. PAES diagnosis is confirmed by MRI, MRA, CT, Angiography, Duplex ultrasound scan. Radiculopathy, soleus sling syndrome, and CECS affecting the superficial posterior compartment need to be excluded.

11 definitions reported in 22 (50%) relevant publications

1 common definitions, first reported in [80]

McArdle’s syndrome

… is defined as autosomal recessive metabolic myopathy causes pain, tightness, swelling, malaise, and lethargy for years at multiple muscle compartments of the upper and lower limbs, leading to fixed weakness, malaise, fatigue, and tiredness. It is more common in young active population; it is a long-term condition that occurs during exercise. The mechanism is an autosomal recessive metabolic myopathy causing exercise-induced rhabdomyolysis due to a deficiency of muscle phosphorylase. McArdle’s syndrome diagnosis is confirmed by resting creatine kinase (CK) followed by 3 consecutive postexercise CK and muscle biopsy. Other medical myopathies and CECS need to be excluded.

1 definition reported in 2 (50%) relevant publications

1 common definition, first reported in [57]

Accessory/low-lying soleus muscle syndrome

… is defined as a space occupying mass which can cause nerve compression which mimics tarsal tunnel syndrome and can also cause increase in the intercompartmental pressure mimicking CECS causes soft tissue swelling that may be painful during physical activity for few months to years. Other symptoms that may be attributed to impingement on neurovascular structures and  paraesthesia and numbness affecting the plantar aspect of the foot. It occurs at the superficial posterior compartment and can be unilateral or bilateral and more common in young active adults.

The mechanism is a rare supernumerary anatomical variant. ALLSMS diagnosis is confirmed by MRI and ultrasound scans. CECS affecting the superficial posterior compartment, PAES, and radiculopathy need to be excluded.

1 definition reported in 5 (20%) relevant publications

2 common definitions, first reported in [155, 156]