Ultrasound of the plantar aponeurosis (fascia)

Objective. To assess the plantar aponeurosis origin (plantar fascia) using high-resolution ultrasound. Design. The sonographic appearance of the plantar fascia in asymptomatic volunteers was compared with the appearance in: (1) clinical idiopathic plantar fasciitis, (2) inflammatory arthropathy without clinically active plantar fasciitis and (3) Achilles tendon or ankle ligament injury. Patients. There were 48 asymptomatic volunteers (96 heels), 190 patients with idiopathic plantar fasciitis (297 heels), 35 with rheumatoid factor negative spondyloarthropathy (70 heels), 17 with rheumatoid arthritis (34 heels), 62 with clinical Achilles tendinitis (93 heels) and 17 with instability secondary to previous ankle ligament injury (17 heels). Results. Compared with the asymptomatic volunteers, the symptomatic plantar aponeurosis demonstrated significant thickening in patients with clinically unilateral (P<0.001) and bilateral (P<0.001) idiopathic plantar fasciitis as well as in patients with spondyloarthropathy (P<0.001). However, the plantar aponeurosis on the asymptomatic side in patients with unilateral idiopathic plantar fasciitis (P<0.2), rheumatoid arthritis (P<0.2) and ankle injury (P<0.1) demonstrated no significant thickening. In patients with idiopathic plantar fasciitis, abnormal plantar aponeurosis echogenicity was seen in 78% and subcalcaneal bone spurs in 24%. Peritendinous edema was present in 5% of all symptomatic heels, subcalcaneal bone erosion in 4% and intratendinous calcification in 3% of heels. Retrocalcaneal bursitis was present in 7% of patients with idiopathic plantar fasciitis, 40% with spondyloarthropathy and 19% with rheumatoid arthritis. Conclusion. Ultrasound allows confirmation of the clinical diagnosis in plantar fasciitis and may provide information as to its etiology.