Chronic Lower Leg Pain in Athletes: Overview of Presentation and Management

Dynamic Imaging is the Ideal Modality for the Diagnosis of Popliteal Artery Entrapment Syndrome

BACKGROUND

Popliteal Artery Entrapment Syndrome (PAES) is a rare vascular condition with significant equipoise on how to properly diagnose and evaluate relevant imaging. This can lead to misdiagnosis and delay in surgical management. The objective of this study is to describe and compare distinct imaging features of dynamic versus static images to help determine the ideal imaging modality for diagnosis of PAES.

METHODS

This is a retrospective review of patients referred for PAES at a single institution. We reviewed noninvasive imaging studies, diagnostic arteriograms, and cross-sectional images which include computed tomography angiography (CTA) or magnetic resonance angiography (MRA). For each affected and unaffected extremity, the characteristic collaterals for PAES were named and measured on arteriogram using Picture Archiving and Communication Software. Available cross-sectional images were also analyzed and compared with arteriogram and intraoperative findings during surgical exploration.

RESULTS

There were 23 patients referred for PAES who underwent diagnostic evaluation and surgical management between 2013 and 2022. All patients had a duplex ultrasound that revealed a mean popliteal peak systolic velocity of 78 cm/sec at rest. With forced plantar flexion, the peak systolic velocity increased to a mean 175 cm/sec. A total of 12 extremities had complete loss of flow with provocation during duplex ultrasound. All patients underwent diagnostic angiography of 46 extremities. All limbs with PAES (n = 35) exhibited complete popliteal artery occlusion during angiography with forced plantar flexion. Distinct angiographic findings on resting images included a well-developed medial sural artery in 100% of limbs with PAES with a mean diameter of 2.7 mm. In limbs without PAES, only 80% had a visualized medial sural artery on arteriogram with a mean diameter of 2.0 mm (P = 0.1). A lateral sural artery was seen in 85% of affected extremities (mean diameter of 1.8 mm), while an anterior tibial recurrent artery was seen in 59% of affected extremities (mean diameter of 1.3 mm). In unaffected limbs, there were no visible lateral sural or anterior tibial recurrent arteries. The mean contrast used with diagnostic arteriograms was 58 milliliters (range 10-100 milliliters). Axial imaging was available for 9 affected extremities. Five had a previous MRA with only 1 being truly positive for arterial compression. Four extremities had previous CTA with 3 being falsely negative despite having type 3 PAES discovered during surgical exploration.

CONCLUSIONS

Dynamic imaging with angiography provides immediate surgeon feedback by visualizing popliteal artery compression and enlarged sural collaterals during resting arteriography. The medial sural collateral is enlarged in patients with PAES and often the lateral sural and anterior tibial recurrent arteries can be visualized as well. CTA and MRA are associated with high false-negative rates, and therefore cause delays in diagnosis and surgical management of PAES. Dynamic imaging should, therefore, be the gold standard for the diagnosis of PAES.

Clinical Outcomes of a Diagnostic and Management Protocol for Popliteal Artery Entrapment Syndrome at a Large Referral Center

OBJECTIVE

Popliteal Artery Entrapment Syndrome (PAES) is a rare clinical entity without a standardized algorithm for diagnosis and treatment. The objective of this study was to evaluate the clinical outcomes of a unique diagnostic and management algorithm for patients with PAES managed at a quaternary referral center.

METHODS

We retrospectively reviewed patients diagnosed with PAES at a single institution between 2013 and 2021. Demographics, physical exam findings, non-invasive imaging results, and angiographic images were assessed to validate a diagnostic and management algorithm (Figure 1). Surgical findings, operative technique, post-operative complications, and symptomatic improvement were assessed to validate this clinical algorithm.

RESULTS

There were 35 extremities in 23 patients treated for PAES (Table 1). The mean age was 28 and 82.6% of patients were female. Physical exam revealed a decrement in pedal pulse with provocative maneuvers in 90% of treated limbs. Noninvasive studies to include treadmill exercise testing revealed a mean ABI drop of 0.28 and positional duplex demonstrated that the mean peak systolic velocity (PSV) in the popliteal artery was 78 cm/sec at rest which increased to 175 cm/sec with provocation. Diagnostic arteriography was performed in all patients and revealed well-developed geniculate and sural collaterals in 100% of treated limbs and complete effacement of the popliteal artery with active provocative maneuvers in all treated limbs (Figure 2). Surgical exposure was performed via a posterior approach and intraoperative completion duplex was performed in all cases. Type III PAES was discovered in 89% of cases. Arterial reconstruction was required in 2 patients who presented with an occluded popliteal artery. All but one patient was discharged on post-operative day one. Wound complications occurred in 4 limbs (3 patients) and included seroma and hypertrophic scarring. All patients experienced symptomatic relief with median follow-up of 4 months.

CONCLUSIONS

We report 100% technical and clinical success in patients with PAES diagnosed and managed using our clinical algorithm. Cross-sectional imaging is not necessary for the diagnosis. Dynamic angiography confirms the diagnosis and intraoperative duplex is essential for successful clinical outcome by confirming complete release of the popliteal artery.

A Comparison of Two Models Predicting the Presence of Chronic Exertional Compartment Syndrome

Clinical history and physical examination are usually not sufficient to diagnose leg chronic exertional compartment syndrome (CECS). Two predictive clinical models have been proposed. The first model by De Bruijn et al. is displayed as a nomogram that predicts the probability of CECS according to a risk score. The second model by Fouasson-Chailloux et al. combines two signs (post-effort muscle hardness on palpation or hernia). To evaluate those models, we performed a prospective study on patients who were referred for possible CECS. 201 patients underwent intra-compartmental pressure at 1-min post-exercise (CECS if ≥ 30 mmHg) - 115 had CECS. For the De Bruijn et al. model, the risk score was 7.5±2.2 in the CECS group and 4.6±1.7 in the non-CECS group (p<0.001) with an area under the ROC curve of 0.85. The model accuracy was 80% with a sensitivity of 82% and a specificity of 78%. Concerning Fouasson-Chailloux et al. model, the accuracy was 86%; the sensitivity and the specificity were 75 and 98%, respectively. The De Bruijn et al. model was a good collective model but less efficient in individual application. In patients having both muscle hardness and hernia, we could clinically make the diagnosis of CECS.