Correlation of High-Resolution Ultrasonography and Conventional Radiography in the Evaluation of Heel Pain at Kenyatta National Hospital

Background: The recent improvements in ultrasound technology coupled with wide availability, safety, portability, cost-effectiveness, non-ionizing with high spatial resolution renders it the initial choice of imaging for the evaluation of most musculoskeletal diseases. Ultrasound is a particularly useful tool to quickly and accurately localize and characterize pathologies of the sole. Heel pain is a common presenting complaint and affects a wide range of the adult population. Plantar fasciitis is the commonest cause in primary care settings. It presents with heel pain, discomfort, and disability limiting day-to-day weight-bearing activities. Although clinical history and examination give useful information, imaging allows further assessment of the plantar fascia and helps to determine the differentials. Purpose of the Study: This study was designed to quantify, characterize and correlate the ultrasonographic and radiographic findings in the diagnosis of plantar fascia disorders in patients presenting with heel pain at Kenyatta National Hospital. Materials and Methods: A prospective descriptive study was conducted over a period of seven months from May 2021 to November 2021 at the Radiology Departments of the University of Nairobi and Kenyatta National Hospital. A total of 59 patients with heel pain were recruited for the study. Both sonographic assessment and plain radiography assessment of the heel were done, and results recorded in the data collection form. Statistical analysis was done with SPSS version 22. Results: Normal findings were recorded in 8 patients (13.6%) with abnormal findings seen in 51 patients accounting for 86.4%. The abnormal findings were twice more common in females (40) than in men (19) with a mean age of 42.3 (SD 12.4) years. Only 9 (15.3%) patients were categorized as having healthy weight, while the rest of the patients ranged from overweight 21 (35.6%) to obese 29 (49.2%). The most prevalent pathology was plantar fasciitis in 45 (76.3%) followed by plantar fascia tears 6 (10.2%). Abnormal plantar fascia thickness (67%) and echogenicity (71.6%) were the most sonographic findings encountered. The sensitivity, specificity, PPV, NPV and diagnostic accuracy of heel ultrasound compared to plain radiography were 97.5%, 60.2%, 69.5%, 97.2% and 78.6% for abnormal plantar fascia thickness, 87.6%, 100%, 100%, 75.5% and 85.9% for calcaneal spurs and 100%, 64.4%, 80.2%, 100% and 85.4% for cortical irregularities, respectively. Conclusion: Heel sonography achieved good diagnostic accuracy when compared to plain radiography in the diagnosis of plantar fascia disorders and it might be considered as an initial imaging modality to confirm clinically suspected plantar fasciitis.