Chronic Compartment Syndrome and Functional Popliteal Artery Entrapment



Chronic Compartment Syndrome and Functional Popliteal Artery Entrapment



William D. Turnipseed


Atypical claudication symptoms in adolescents and young adults are often associated with athletic overuse injuries and are clinically manifested by isolated muscle group cramping and focal paresthesias on the dorsal or plantar surface of the feet. These complaints commonly have a delayed onset with exercise and last for an extended period after exercise. Atypical claudication symptoms that occur in the absence of obvious vascular disease or musculoskeletal injury can indicate the presence of chronic recurrent exertional compartment syndrome (CRECS) or functional popliteal entrapment syndrome (FPAES). These conditions are often confused with each other because the complaints are similar in quality and anatomic location and commonly overlap. CRECS and FPAES require distinctly different surgical procedures for successful cure. This chapter describes the clinical presentation, diagnostic testing, and treatment differences in patients with CRECS and FPAES.



Evaluation


Over the past few decades, referral patterns have changed. Previously, most patients were sent from orthopedic or sports medicine consultants because of persistent muscular cramping and pain without obvious vascular or orthopedic origins. However, as awareness of overuse syndromes, such as CRECS and FPAES, has spread, coaches, trainers, teammates, and parents searching the Internet have been consistent referral sources. Claudication complaints in these patients are atypical because symptoms affect isolated muscle groups (anterior lateral, posterior superficial, distal deep) in the lower leg, with occasional plantar or dorsal pedal paresthesias. Symptoms are associated with fixed but long exercise distances, often measured in miles, and commonly take hours to resolve after exercise. These symptoms develop in the absence of obvious vascular or musculoskeletal abnormalities.


The workup of these patients includes a detailed history, physical examination, and selective noninvasive vascular imaging. The history is often more revealing than a physical examination because most are healthy adolescents or young adults actively engaged in sports activities. All patients have screening ankle-to-brachial indices (ABIs) and stress positional plethysmography using the Flow Laboratory Pulse Volume Recorder (Parks Medical Electronics, Aloha, OR) to screen for arterial occlusive disorders and popliteal entrapment. Duplex imaging is only used when the patient comes to the hospital with chronic limb swelling in order to rule out postphlebitis syndrome or venous valvular incompetence. Duplex imaging is also helpful when a popliteal mass is present to rule out popliteal aneurysm or Baker’s cyst. Occasionally, three-phased nucleotide bone scanning is performed in patients with chronic medial tibial bone pain to rule out the presence of periostitis or microcortical fractures.


Popliteal entrapment screening is done with stress positional testing using a 10-cm cuff inflated to 60 mm Hg with the patient supine, the knees extended, and the foot in neutral, forced plantarflexion, and dorsiflexion positions. Abnormal stress position testing consists of an ABI decrease greater than 30% or flattening of the plethysmographic waveforms with plantarflexion or dorsiflexion, or both. My group does not routinely use stress positional duplex imaging unless there is a clinical suggestion that venous impingement is the basis for suspected symptoms. We found that plethysmography or duplex imaging by themselves are not useful for determining whether abnormal musculotendinous anomalies are responsible for popliteal impingement.


We prefer magnetic resonance angiography (MRA) to evaluate patients with suspected popliteal entrapment. The combination of stress positional T2-weighted magnetic resonance imaging (MRI) and MRA allows definition of normal and abnormal muscular tendinous structures within the popliteal fossa as well as accurate arterial imaging in younger healthy patients.


Compartment pressures are routinely measured using the Stryker computer system (Stryker Surgical, Kalamazoo, MI) when claudication symptoms are referable to the anterior lateral or posterior superficial muscle groups. Resting pressures are measured bilaterally, even if complaints are unilateral. Pressures after exercise are only measured if patients had been inactive for longer than 1 month before examination because a prolonged period of inactivity results in loss of muscle tone and compartment pressures that do not accurately reflect the active physiologic status of the conditioned athlete. When exercise testing is required, the patients run outside the clinic until symptoms develop, thereby more accurately duplicating conditions under which they normally exercise. Pressures normally return to baseline level within 3 to 5 minutes after exercise. With this in mind, compartment pressures are measured at least 10 minutes after exercise. In our practice we consider normal resting pressures to be between 15 and 17 mm Hg. Pressures in excess of 25 mm Hg exceed venous closing pressure and are considered abnormal.

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Jul 15, 2018 | Posted by in CARDIOLOGY | Comments Off on Chronic Compartment Syndrome and Functional Popliteal Artery Entrapment

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