A Rare Case of Atraumatic Unilateral Isolated Compartment Syndrome of the Peroneal Compartment Leading to Common Peroneal Nerve Palsy

Abstract

Acute Compartment syndrome (ACS) is an orthopaedic surgical emergency with very poor prognosis when left untreated. The majority of cases are preceded by trauma, but importantly there is a small percentage of patients presenting with non-traumatic causes. Although rare with only two other case reports describing non-traumatic, spontaneous compartment syndrome of the peroneal compartment, the complications are equally devastating. We report a 67-year-old female with a history of Factor V Leiden, pulmonary embolism (PE) and deep vein thrombosis (DVT). She was seen by orthopaedic surgery six weeks after acute onset right leg pain with associated foot-drop. Her symptoms were initially managed by a medical team as she had no history of trauma and no fractures were evident on plain radiographs. This was on a background of severe bilateral knee osteoarthritis, chronic bilateral lower leg pain and neurogenic claudication for the preceding six months. Given her atypical presentation with confounding comorbidities, she was admitted under the medical team for further investigations instead of urgent fasciotomy. As orthopaedics was not involved in the acute phase of her symptoms, a non-surgical approach was taken. MRI right knee and calf six weeks after onset of symptoms were suggestive of sequela of compartment syndrome isolated to the peroneal compartment. This scan showed myonecrosis in this compartment as well as denervation myopathy of the anterior compartment. Over the next twelve months, there was resolution of leg pain and gradual progression of a positive tinel’s sign from the fibular head to anterior shin with associated return of some ankle range of movement and power. Given the atraumatic presentation and patient risk factors, we believe she suffered a venous thrombotic event at the popliteal trifurcation leading to a subacute compartment syndrome of the peroneal compartment. Swelling of the compartment led to compression of the deep peroneal nerve, causing denervation of the anterior compartment. This is of interest given the rarity of such presentations, and will serve as a timely reminder for non-traumatic causes of ACS. Keywords: Compartment syndrome, non-traumatic, Factor V Leiden, common peroneal nerve palsy.