Plantar Fasciitis Workup

Updated: Jan 22, 2019
  • Author: Craig C Young, MD; Chief Editor: Craig C Young, MD  more...
  • Print
Workup

Approach Considerations

Usually, laboratory studies are not needed in the workup of plantar fasciitis. However, laboratory tests may be used to investigate other causes of heel pain if suspected.

Radiographs typically are not necessary for diagnosing plantar fasciitis. However, to rule out a bony tumor or fracture, always consider obtaining at least a plain radiograph before administering a corticosteroid injection.

Imaging studies may be helpful in defining the extent of the condition or in establishing the diagnosis if another disorder is suspected as the cause of the patient’s heel pain. [30] Ultrasound may be useful in following treatment response in chronic cases. [31]

Next:

Laboratory Tests

No specific laboratory studies are needed to confirm the diagnosis of plantar fasciitis, unless there is a suspicion of an alternative cause, such as if there is a bilateral presentation that appears in association with some seronegative spondyloarthropathies. In such cases, the standard hematologic and chemistry studies may include, but are not limited to, a complete blood count (CBC), determination of the erythrocyte sedimentation rate (ESR), a complete metabolic panel, and rapid plasma reagin and rheumatoid factor studies.

Previous
Next:

Radiography

Plain radiographs may reveal a plantar heel spur, which delineates the presence of abnormal stresses across the plantar fascia for at least 6 months. [25] Over time, the spur forms in a manner consistent with Wolff’s law—that is, “form follows function.” It is not the cause of the symptoms but, rather, a sequela of the process; thus, it does not require specific treatment or removal. About 50% of symptomatic patients and 20% of asymptomatic patients have heel spurs. [32, 33] ; however, many patients with plantar fasciitis have no heel spur.

The heel spur is best seen on the lateral view, located at the anteroinferior aspect of the calcaneus. Radiographic films of the foot should be obtained before corticosteroid injection, as well as in any patient who continues to have symptoms despite 1-2 months of conservative, nonsurgical treatment (to ensure that a tumor or fracture has not been missed). Standing lateral radiographs may help in assessing the possibility of stress fractures of the calcaneus (a rare condition) in patients with pain at rest.

Previous
Next:

Other Tests

Magnetic resonance imaging

Reserve magnetic resonance imaging (MRI) for the rare cases in which imaging studies are needed to confirm plantar fasciitis or partial and complete plantar fascia rupture. Plantar fascia thickening and surrounding edema can also be detected on MRI.

Ultrasonography

Ultrasonography, though rarely used, can aid in the diagnosis of plantar fasciitis, much as MRI can. A marked increase in the thickness of the fascia (eg, from the normal 2-4 mm to 5-7 mm) may be noted. Other signs seen on ultrasonography include hypoechogenicity and edema of the fascia where it inserts into the calcaneus, as well as loss of definition between the fascia and the surrounding soft tissue. A more recent study has suggested that the finding of biconvexity on ultrasound may predict less response to treatment with mechanical support of the plantar fascia. [34] This study also found that increased thickness of the plantar fascia did not correlate well initially and especially as symptoms resolved.

Bone scanning

Three-phase bone scanning is helpful for patients in whom there is a suggestion of a stress fracture of the calcaneus despite negative findings from plain radiography. In plantar fasciitis, a bone scan often shows increased uptake over the medial calcaneal tuberosity as a result of the local inflammation. This finding should not be confused with that of a stress fracture showing increased uptake elsewhere in the calcaneus. Bone scans are also used to evaluate for tumors and infection.

Computed tomography

If stress fracture remains a significant consideration despite negative radiographic findings, further imaging studies could include computed tomography (CT).

Electromyography

Electromyography (EMG) is useful to evaluate for possible neurologic entrapment syndromes.

Previous