Description
Compartment syndrome is a limb threatening condition that results when there is an abnormal increase in pressure within a closed myofascial space. It leads to impaired perfusion of muscles and nerves accompanied by compromised neuromuscular function that can result in permanent damage (DeLee et al., 2003).
Compartment syndrome is either acute or chronic. The nature of the conditions can be acute or chronic. Acute compartment syndrome develops quickly in a previously normal leg. The usual causes are trauma, external compression and impaired outflow such as from a massive venous clot. Chronic compartment syndrome, however, is a temporary condition that results from activity/exercise and will resolve spontaneously (DeLee et al., 2003).
Structure and function
There are four well-define compartments of the leg. The anterior compartment of the leg consists of four muscles: tibialis anterior, extensor hallucis longus, extensor digitorum longus, and fibularis tertius. As a group, the muscles in the anterior compartment of the leg dorsiflex the foot, extend the toes and aid in foot inversion (Drake et al., 2005). The anterior tibial artery, a branch of the popliteal artery, supplies the muscles in the anterior compartment and extends down the leg on the interosseus membrane accompanied by the deep fibular nerve (Drake et al., 2005). This nerve is the primary innervation of the anterior compartment and originates in the lateral compartment as one of the two divisions of the common fibular nerve (Snell, 2008). The lateral compartment consists of two muscles: fibularis longus and fibularis brevis, which function to collectively evert to the foot. Both of these muscles are innervated by the superficial fibular nerve, which is the other terminal branch of the common fibular nerve (Moore et al., 2010). In contrast to the anterior compartment, the lateral compartment does not have an artery travelling through it but rather, has perforating branches of the anterior tibial artery proximally and branches of the fibular artery distally which supply it (Moore et al., 2010). The posterior compartment can be divided into the deep and superficial posterior compartments. The superficial posterior compartment includes the grastrocnemius, soleus, and plantaris muscles (Drake et al., 2005). As a whole, these muscles are powerful plantarflexors. The deep posterior compartment contains the popliteus, flexor hallucis longus, flexor digitorum longus, and tibialis posterior muscles (Moore et al., 2010). The popliteus muscle acts on the knee joint, whereas the other muscle aid in ankle plantarflexion. Furthermore, two of these muscles, flexor hallucis longus and flexor digitorum longus, flex the toes (Moore et al., 2010). As the popliteal artery enters the posterior compartment of the leg it gives off multiple branches. Its largest branch is the posterior tibial artery, which supplies much of the posterior compartment of the leg. The fibular artery, which also supplies the posterior compartment of the leg, is the largest and most important branch of the tibial artery as it descends distally (Moore et al., 2010). The tibial nerve, which originates from the sciatic nerve, supplies all the muscles in both of the superficial and deep posterior compartments of the leg (Moor et al., 2010). Another nerve that is commonly affected by posterior compartment syndrome is the sural nerve, which runs superficial to the gastrocnemius muscle and penetrates into the deep fascia in the middle of the leg (DeLee et al., 2003). Like the superficial fibular, deep fibular, and tibial nerves, the sural nerve has a sensory component and therefore, contributes to the clinical manifestations of compartment syndrome.
Clinical Manifestations
Patients suffering from exertional compartment syndrome, most frequently runners, often provide a typical history of gradual onset of diffuse aching pain with exercise. An important differentiating factor between compartment syndrome and other conditions is that there is no pain at rest. Exertional compartment syndrome more commonly occurs in endurance athletes, and less often in anaerobic athletes such as sprinters. Eventually, the pain becomes so great that the athlete experiences a bursting sensation in his or her muscles and may be forced to discontinue exercise (Rolf, 2007). The most frequent locations of exertional compartment syndrome are the anterior and deep posterior compartments of the leg, accounting for approximately 80% of all cases (DeLee et al., 2003). Parasthesias may develop in the sensory distribution of the nerve that is affected. For example, in the case of deep posterior compartment syndrome, parasthesia would affect the plantar aspect of the foot. Conversely, the dorsum of the foot would be affected in patients with anterior compartment syndrome (DeLee et al., 2003). In addition to these signs and symptoms, there is intense tenderness on palpation and the muscle bulk itself is very firm, accompanied by a shiny appearance (Rolf, 2007).
Red flags
Exertional compartment syndrome should not be confused with acute compartment syndrome which is limb threatening and occurs after significant trauma. In addition, stress fractures are another common injury seen in long-distance athletes and is also made worse with activity. In contrast, however, stress fractures will manifest with rest/night pain and point tenderness on the tibia.
Epidemiology
Much of the epidemiological data concerning chronic exertional compartment syndrome is unknown. Generally males and females seem to be affected equally however some studies have suggested that women are more susceptible. This condition develops most commonly in younger athletes. Exertional compartment syndrome may be under-diagnosed because firstly, most individuals who suffer from the condition modify their activity level to manage their symptoms and as such likely never receive a confirmed diagnosis. Secondly, many coaches, athletic trainers, and primary care physicians under-diagnose exertional compartment syndrome because invasive pressure measurements are the gold stand for diagnosis but are rarely performed in these settings.
Little has been written about the economic burden of exertional compartment syndrome.
Pathophysiology
Unlike acute compartment syndrome, the pathophysiology of exertional compartment syndrome is not well understood. There are many conflicting studies in the literature about the role of muscle ischemia in the generation of pain (Kaeding and Amendola, 2009). It has been shown that there is an abnormal increase in compartmental pressure in exertional compartment syndrome ultimately leading to transient ischemia and subsequent pain. This coincides with the fact that during muscle contraction there is a substantial increase in intracompartmental pressure generally greater than 80 mmHg (DeLee et al., 2003).
The normal physiologic response to exercise is an increase in blood flow to active muscles that forces the muscles to expand causing a transient increase in compartmental pressure, increased blood volume, muscular edema, and hypertrophy. While it usually takes approximately 5 minutes for pressures to normalize after muscle contraction, in the case of exertional compartment syndrome, pressures remain elevated for greater than 30 minutes further impairing blood flow (Reneman, 1975).
Differential diagnosis
Leg pain is a common presenting complaint in athletes. Due to the fact that there is a broad range of conditions that can cause leg pain, it is crucial for the physician to pay close attention to the history presented by the patient and to ensure a full clinical evaluation is performed. The description of pain can provide more than enough information to rule out exertional compartment syndrome. Pain at rest or pain at first impact suggests the patient is suffering from a stress fracture, muscle strain, or medial tibial periostitis (Roberts, 2004). Stress fractures could also be indicated by focal pain on palpation of the tibia. Focal pain in the muscle itself is usually due to muscle strains or tendinopathy. Conversely, if the pain is more diffuse on palpation and located along the posterior medial border of the tibia, it is commonly a result of shin splints. Tumours, cysts, and muscle herniation are usually indicated by palpable masses in the soft tissue itself and are not seen in exertional compartment syndrome. Another important condition to keep in mind is popliteal artery entrapment syndrome which often presents, like exertional compartment syndrome, with exertional pain in the posterior compartments and proximal posterior leg. Other conditions, which have significant overlap with exertional compartment syndrome, are vascular claudication, medial and lateral tibial stress syndrome, infections and trauma.
Etiology
Chronic exertional compartment syndrome is primarily caused by exercise which results in increased tissue pressure. As the intracompartmental tissue increases in pressure there is a decrease in tissue perfusion and this leads to muscle ischemia and subsequently cell edema. This cascade of pathological events proceeds in a cyclic fashion and propagates as the condition worsens. The fascial covering of each muscle compartment is also a limiting factor in determining the amount of muscle expansion possible. It is inherently noncompliant and as such muscle swelling will increase compartmental pressure resulting in a compromised arterial pressure and impaired oxygen and nutrient transport to the muscle capillary beds. Although the mechanism contributing to exertional compartment syndrome has been discussed greatly, recent MRI and other nuclear medicine blood flow studies have not shown post-exercise ischemia in patients with documented exertional compartment syndrome (Amendola et al., 1990).
Radiographic and laboratory findings
The gold standard for the diagnosis of exertional compartment syndrome is compartment pressure testing. There are a variety of techniques that have been developed and used to accurately assess the condition. The wick catheter and slit catheter techniques are two of the most commonly used methods and have been proven to be the most reliable tools (DeLee et al., 2003). The slit catheter, also known as the Whiteside technique, is an injection where the compartmental pressure is measured via a fluid column. The fluid column is then connected to an external transducer to measure the pressure within the compartment. The wick catheter technique uses a specially prepared catheter with a fibrous material in the lumen, which is connected to a pressure transducer filled with a heparin-containing solution to prevent any clotting (Roberts, 2004). The catheter is then placed in the skin through a large cannula. The use of this cannula provides a major benefit in that it allows for multiple pressure readings and avoids multiple needle sticks.
Common radiographic techniques such as X-Rays and CT scans are not useful in making a diagnosis of exertional compartment syndrome. They do however, remain important in identifying other pathologies related to the condition and in ruling out any associated injuries (DeLee et al., 2003). While literature discussing the application of MRI imaging in the diagnosis of exertional compartment syndrome is inconclusive, it remains an attractive technique due to its non-invasive nature (DeLee et al., 2003).
Although there are no universal criteria for diagnosis, the general accepted testing method is to measure intracompartmental pressure at rest, then have the patient perform exercise until a symptomatic level is reached, and then measure the pressure again at 1 minute and 5 minutes post-exercise. Pedowitz et al. defined the criteria for the diagnosis of exertional compartment syndrome in the leg as meeting one or more of the following requirements (Pedowitz et al., 1990):
- A rest compartmental pressure of 15 mmHg or higher
- A 1 minute post-exercise pressure of 30 mmHg or higher
- A 5 minutes post-exercise pressure of 20 mmHg or higher
Risk factors and prevention
The most common risk factor of developing exertional compartment syndrome is repetitive exercise. As stated previously, young athletes most frequently develop this condition, especially those who are engaged in sports or exercises such as running, swimming, football, soccer, biking, tennis and gymnastics. There are some reports implicating external compression such as in a ski boot.
The condition is both rare and difficult to diagnose. The only prevention strategy that has been identified is activity modification.
Treatment options
Fasciotomy of the affected compartment is the only definitive treatment. The goal of this surgery is to release or decompress the fascial covering of the affected compartments (Roberts, 2004). Conservative treatments such as exercise modification, orthotics, and medications have proven to be largely unsuccessful (DeLee et al., 2003). Surgical decompression has been found to allow patients to make a significant, if not complete, recovery in 90% of cases (DeLee et al., 2003). Patients are usually able to train normally 3-6 weeks post-operatively. Surgical failures can be associated with too short a fasciotomy, injury to the superficial fibular nerve, postoperative hematoma and infection. Recent studies have shown, however, that long-term outcomes for anterior and lateral compartments are better than for the deep posterior compartment (DeLee et al., 2003).
There are a variety of described fasciotomy techniques. Historically, fibulectomy has been described, which effectively decompresses all of the compartments of the leg but carries a high level of morbidity. Modern approaches include either a single or dual incision. The single incision technique is performed by making an incision along the lateral side of the leg from the proximal fibula to the lateral malleolus. The dual incision fasciotomy, is performed by making one incision between the tibia and fibula decompressing the anterior and lateral compartments of the leg. The second incision, commonly known as the posteromedial incision, is made just medial to the posteromedial border of the tibia, exposing the deep and superficial posterior compartments of the leg. Open procedures are preferred for acute compartment syndrome, while mini-incision or arthroscopic assisted techniques can be used in the treatment of chronic exertional compartment syndrome.
Outcomes
Compartment release can be done on an outpatient basis. Post-operatively, patients can weight bear as tolerated but are usually protected with crutches and encouraged to rest and elevate the limb. Rehabilitation involves early range of motion, gradually increased to low impact activities such as cycling and swimming once wounds have healed. More intense exercise routines can begin at approximately 3-4 weeks post-surgery, with full recovery expected anywhere between 6 and 12 weeks.
As a whole, surgical intervention has good success in patients with exertional compartment syndrome. That being said, prognosis seems to be better following fasciotomy of the anterior compartment of the leg compared to the deep posterior compartment. Most of the complications experienced are a result of the surgical intervention itself such as infection, haemorrhage, reaction to anaesthesia, and wound breakdown. If the compartmental decompression is unsuccessful patients will suffer from recurrent pain. In rare occasions, recurrent exertional compartment syndrome can exist and is thought to be related to severe scarring. The most serious complication is injury to a peripheral nerve during surgery, the most common of which is the superficial fibular nerve.
Holistic medicine
N/A.
Miscellany
N/A
Key terms
- Chronic Exertional Compartment Syndrome
- Exercise Induced Compartment Syndrome
- Increased Compartmental Pressure
- Fascia
- Tissue Perfusion
- Leg Pain
- Muscle Ischemia
- Running injury
Skills and competencies
Physical examination skills, including:
- Peripheral nerve exam; specifically superficial fibular, deep fibular and tibial nerves
- Assessment for compartment syndrome; specifically vascular exam, nerve exam, eliciting pain with passive stretch of a compartment
REFERENCES
Amendola A, Rorabeck CH, Vellett D, et al. The use of magnetic resonance imaging in exertional compartment syndromes. Am J Sports Med. Jan-Feb 1990;18(1):29-34.
DeLee, J.C., Drez, D., and Miller, M.D. (2003). DeLee and Drez’s Orthopaedic Sports Medicine 2nd Edition: Principles and Practice. Philadelphia: Saunders, An Imprint of Elsevier Inc.
Drake, R.L., Vogl, W., Mitchell, A.W.M. (2005). Gray’s Anatomy for Students. Philadelphia: Churchill Livingston, An Imprint of Elsevier Inc.
Kaeding, C., Amendola, A. (2009) American Association of Orthopaedic Surgery (AAOS) Comprehensive Orthopaedic Review: Section 5: Sports Medicine.
Moore, K.L., Dalley A.F., Agur, A.M.R. (2010). Clinically Oriented Anatomy: 6th Edition. Lippincott Williams & Wilkins.
Pedowitz RA, Hargens AR, Mubarak SJ, Gershuni DH. Modified criteria for the objective diagnosis of chronic compartment syndrome of the leg. Am J Sports Med. Jan-Feb 1990;18(1):35-40.
Reneman RS. The anterior and the lateral compartmental syndrome of the leg due to intensive use of muscles. Clin Orthop Relat Res. Nov-Dec 1975;69-80.
Roberts, W.O. (2004). Bull’s Handbook of Sports Injuries: 2nd Edition. McGraw-Hill
Rolf, C. (2007) Sports Injuries Handbook. London: A & C Black Publishers Ltd
Snell, R.S. (2008). Clinical Anatomy By Regions: 8th Edition. Lippincott Williams & Wilkins
