exertional compartment syndrome of the forearm cover

chronic exertional compartment syndrome of the forearm

case presentation

A healthy, 23-year-old male elite rower presents with a 1-year history of persistent forearm pain. He describes an onset of pain after ten minutes of rowing that is progressive and worsens to the point that he needs to stop.  He also describes some numbness over his second and third digits on occasion.  He notes forearm swelling after rowing.  His symptoms normally resolve after about 30 minutes after stopping. He did visit an urgent care and x-ray studies were normal.  Which of the following is the most likely diagnosis?

A. Median nerve compression
B. Extensor tenosynovitis
C. Chronic exertional compartment syndrome of the forearm
D. Ulna fracture

introduction

Chronic exertional compartment syndrome of the lower limb (CECS) is well reported, but CECS of the forearm is less known.  CECS of the forearm is a rare condition in the general population, but can be observed in motorcycling racers, climbers, and rowers [1].  A high index of suspicion is necessary to diagnose it in most cases.

The etiology of chronic exertional compartment syndrome (CECS) remains debated. Currently, the most accredited theory reports that a non-compliant fascia stiffens the compartment that fails to adapt to increased blood flow and muscle volume during exercise [2]. CECS was first described in1912, but it was not linked to increased intracompartmental pressure until 1956 [4].   Unlike acute compartment syndrome, the ischemia associated with CECS is reversible, with symptoms typically receding after the cessation of exercise and patients are typically asymptomatic at rest [5].  

CECS of the forearms was first described in 1983 [6]. In 1985, Detmer et al. pointed out the higher incidence of CECS of the forearms in athletes [7]. Cases of manual laborers, gymnasts, rock climbers, rowers, tennis players, and weight lifters were described early, but more recent studies have been dominated by motocross athletes [1].

Four compartments are usually described in the forearm: superficial volar compartment, deep volar compartment, lateral compartment, and dorsal compartment [3]. Some will also describe a deep dorsal compartment [16] and other authors will only describe three compartments (mobile wad, dorsal, volar).  In most cases of CECS of the forearm described in the literature, the superficial and deep volar compartments, containing the flexors, are involved. Involvement of the superficial volar compartment, in particular, has been most frequently cited. However, there are reports of the extensor compartments being involved in isolation, as well [4].

Image 1: Anatomy of the forearm and compartments.  Adopted from [16].

physical examination

As with most conditions, it is important to take a thorough history and perform a physical examination to properly diagnose this condition. A full musculoskeletal exam, testing range of motion and strength, neurological exam, and vascular exam should be performed, with a special focus on the affected limb or limbs.  Most will describe forearm pain, stiffness, decreased muscle strength, and paraesthesias.  With the sports that this commonly affects, many times the condition is bilateral.   Immediately after exercise, the affected compartment may be swollen and tender on the physical exam.  It is important to note that the physical exam of patients affected by CECS can be completely normal as symptoms only appear during exercise. Symptoms will typically start minutes after beginning exercise and dissipate within 10–20 minutes of stopping.

diagnostics/imaging

Other diagnostic tools and tests can be used to aid in the diagnosis of CECS.  Intracompartmental pressure monitoring may also be used to support the diagnosis. The Stryker ‘STIC catheter’ is the most commonly used device, though other kits and pressure monitors are becoming more available.  However, it should be noted that there is no consensus on diagnosing CECS solely based upon compartment pressures in the upper extremity. 

Pedowitz et al. defined the most commonly accepted criteria for diagnosing CECS in the lower leg in 1990 [8]. A pre-exercise pressure of greater than or equal to 15 mm Hg, a 1-minute post-exercise pressure of greater than or equal to 30 mm Hg, or a 5-minute postexercise pressure of greater than or equal to 20 mm Hg are all diagnostic of CECS of the lower extremity [8].

The rarity of cases of CECS in the upper extremity makes similar diagnostic criteria difficult to define for patients whose forearms are affected. However, a pressure of 30 mm Hg in any compartment of the forearm generally supports the diagnosis of CECS [9]. 

Additional imaging including magnetic resonance imaging (MRI) may be ordered by some providers.  In some settings, a dynamic MRI may show increased edema over the forearm musculature after exercise.  Verleisdonk et al. [10] used dynamic MRI as a diagnostic measure for chronic exertional compartment syndrome of the lower leg because there was a significant increase in T2 signal intensity in the involved compartment after exercise compared with controls. The T2 postexercise hyperintensity resolved after decompression fasciotomy [10].

Figure 2.  Dynamic MRI of the forearm in a rower.  Adopted from [17].

When there are associated neurological symptoms, nerve conduction studies (NCS) are recommended. Static nerve conduction studies and electromyography results are usually normal.  Dynamic NCS may demonstrate the same inaccuracies encountered with other dynamic nerve compression problems such as pronator syndrome. Myelin damage is required to produce an alteration in nerve conduit velocity.

treatment

Managing patients with CECS can present a challenge to clinicians. Regulating the activity that triggers the patient’s symptoms is the only nonoperative method that has been shown to alleviate symptoms. However, this may not be acceptable to some patients who are afflicted with CECS, especially those who are athletes. Unfortunately, no other nonoperative therapies have been shown to be efficacious for symptoms refractory to the cessation of activity [11,4].

Initial nonoperative management consists of deep tissue massages and stretching prior to exercise. However, it should be emphasized that these interventions do not alter the underlying structural pathology in CECS. Thus, while they may serve to delay the onset of symptoms during exercise, these interventions will not eliminate them [4].  Occupation and physical therapy to try to remedy other surrounding tendonitis or inflammation may be attempted.

For patients who do not respond to nonoperative therapy, or activity modification is unfeasible, fasciotomy may be considered.  Athletes are advised that not all patients experience full symptom resolution after fasciotomy [12].  Although most cases documented in the literature report complete resolution of symptoms and a return to athletic training, some report only partial symptom resolution and several incidences of scar widening [12,13].

As with CECS of the lower extremities, there have been newer and less invasive techniques being used.  These endoscopic-assisted and mini-open fasciotomies are being used reduce time to return to competition [1,9,14].  These techniques evolved owing to the belief that only the proximal two-thirds of the compartment needs to be released, because that is where the expansile muscle bellies lie [15].  Harrison et al. and Croutzet et al. reported complete resolution of preoperative symptoms in 6 and 8 athletes, respectively, after mini-open fasciotomy.  It is also of note that all athletes returned to sports in 4 and 6 weeks, respectively [9,15]. Barrera-Ochoa et al. compared results of mini-open and open fasciotomies and found no significant difference in pain and function scores visual analog scale and Quick-Disabilities of the Arm, Shoulder, and Hand questionnaire in 34 motocross racers [1]. More minor complications occurred after mini-open fasciotomies, including hematomas, unspecified skin issues, and superficial infections also [1].

Figure 3.  Studies performed on CECS and techniques described .  Adopted form [17].

Image 4: Images from a volar compartment release  Adopted from [17].

Summary

In summary, exertional compartment syndrome is a rare condition that most often affects athletes and others who complete tasks that require repetition that many times requires a high index of suspicion.  Afflicted patients most often report exercise-induced pain that subsides upon the cessation of activity. The diagnosis is often based on the history of symptoms and a post-exercise physical exam.  Intracompartmental pressure testing can also be used to support the diagnosis.  Patients with CECS of the forearms who choose nonoperative management generally have a poor prognosis. Patients who undergo surgery, via fasciotomy, usually have good results, though there is low risk of postoperative recurrence.

CASE CONCLUSION

C.  Exertional compartment syndrome is a rare condition that most often affects athletes and others who complete tasks that require repetition and is most common among rowers and motocross riders. Afflicted patients most often report exercise-induced pain, tightness and paresthesias that subside upon the cessation of activity. The diagnosis is often based on the history of symptoms and a post-exercise physical exam.  Intracompartmental pressure testing can also be used to support the diagnosis.  Among the answer choices, this is the most likely diagnosis.  Median nerve compression would unlikely be intermittent and would not normally resolve with rest.  There were no fractures on the x-ray performed making a fracture less likely.

References

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