Heel fat pad syndrome

Heel fat pad syndrome, also known as plantar fat pad syndrome or heel fat pad atrophy is a common but not well-known known cause of heel pain in the adult population.

Epidemiology

Heel fat pad syndrome is common. It is the second most common cause of plantar heel pain after plantar fasciitis It is thought to account for up to 15% of cases with ¹.

Risk factors

The following factors have an increased risk of plantar fat pad syndrome ^1,2:

• obesityobesity
• ageing
• rheumatoid arthritis
• corticoid injections

Clinical presentation

Typical complaints are pain and tenderness beneath the posterior weight-bearing bearing portion of the calcaneus aggravated during standing or prolonged weight-bearing bearing and walking on hard surfaces ^1-3.

Pathology

Heel fat pad syndrome is thought to arise from rupture of the fibrous tissue septa with attrition of the fat pad and decreased shock absorption capacity ^1,5.

Aetiology

Plantar fat pad syndrome can be a result of acute trauma or from chronic overuse such as excessive heel strike.  

Radiographic features

Plain radiography

Plain radiography might show the absence of a plantar calcaneal spur.

Ultrasound

Ultrasound might show a reduction in thickness of the heel fat tissue with overall normal echogenicity ⁴.

A plantar heel fat pad thickness of <12 mm might suggest fat pad atrophy.

CT

CT might visualize fat pad atrophy and thickened fibrous bands.

MRI

MRI can depict band-like like signal intensity changes of the fat pad reflecting fibrotic and a reduction of the thickness of the plantar fat pad ^4,5. In addition, it allows evaluation of the plantar fascia, the calcaneus, the Achilles tendon and flexor digitorum longus and flexor hallucis longus tendons as well as the tarsal tunnel and the plantar muscles.

Signal characteristics

• T1: low signal
• T2: high signal
• STIR: high signal

Treatment and prognosis

Treatment is conservative with proper footwear, insoles or heel cups and taping, and mobilisation and manual therapy. Patient education about the discontinuation of symptom increasing activities such as high impact exercises should also occur. Additionally, the pain might be treated with rest and ice and non-steroidal anti-inflammatory drugs ^1,2.

Differential diagnosis

Other clinical conditions mimicking the imaging appearance of heel fat pad syndrome include ^1-5:

• plantar fasciitis: inflammatory changes of the proximal plantar fascia, plantar calcaneal spur
• plantar fibromatosis: nodular thickening of the plantar fascia
• plantar fascial xanthoma: fusiform tendinous or aponeurotic enlargement of the plantar fascia
• plantar fascial tear
• Baxter neuropathy
• tarsal tunnel syndrome
• flexor hallucis longus or flexor digitorum longus tenosynovitis
• insertional Achilles tendinopathy
• retrocalacaneal bursitis