Contemporary Outcomes of Surgical Decompression for Functional Popliteal Entrapment Syndrome.

INTRODUCTION: Functional popliteal entrapment syndrome (FPES) is an underrecognized source of leg pain caused by dynamic compression of the popliteal vessels by surrounding musculature in the absence of anatomic abnormality. Late recognition and difficulty capturing this entity across imaging modalities can lead to significant morbidity in an often young and active patient population. Surgical outcomes and optimal diagnostic strategies remain uncertain.

METHODS: We performed a retrospective cohort study of all patients undergoing surgical decompression for FPES at an academic medical center between 2018-2022. Preoperative symptoms, patient characteristics, imaging, operative details, and follow-up were captured. The primary outcome was symptomatic improvement at last clinic visit. Secondary outcomes included symptomatic improvement at 6 months and postoperative complications.

RESULTS: A total of 24 extremities (16 patients) were included. Mean (standard deviation [SD]) age was 23.3 (6.4) years and 75.0% of patients were female. Median (interquartile range [IQR]) symptom duration prior to decompression was 27 (10.7-74.6) months. Preoperative symptom severity in the affected extremity was as follows: 33.3% limited from peak exercise, 25% unable to exercise, and 41.7% with debilitating symptoms that affected activities of daily living. Preoperative imaging with provocative maneuvers included duplex ultrasound (87.5%), magnetic resonance angiography (MRA,100%), and digital subtraction angiography (DSA,100%). Using DSA as the gold standard, sensitivity for detection of FPES was 85.7% for duplex and 58.3% for MRA. Median (IQR) follow-up was 451 days (281-635). Most patients demonstrated durable improvement in the affected extremity, with 29.2% realizing complete resolution of symptoms and 37.5% reporting symptomatic improvement at last clinic visit for a total of 66.7%. 20.8% had initial improvement but developed recurrent symptoms and were found to have elevated compartment pressures consistent with chronic exertional compartment syndrome (CECS) and were treated with formal fasciotomy. Repeat decompression was required in one extremity (4.2%) due to recurrent symptoms. Two patients (8.3%) had minimal or no improvement in their affected extremity and workup for the cause of continued discomfort was ongoing.

CONCLUSION: Delays in diagnosis of FPES are common. Provocative maneuvers until replication of symptoms across multiple imaging modalities may be necessary to reliably identify the disease process. Surgical decompression improved or completely resolved symptoms in two-thirds of extremities. Treating physicians should maintain suspicion for comorbid CECS, especially if symptoms recur or persist following decompression.