An Evidence-Based Medicine Approach To Plantar Fasciitis
Taking an exhaustive look at the literature on plantar fasciitis, this author discusses what studies have revealed on diagnostic imaging and explores the reported findings for a wide range of treatments, including orthotics, platelet rich plasma, extracorporeal shockwave therapy and plantar fasciotomy.
Plantar fasciitis remains one of the most common pathologic conditions for which patients seek podiatric care. Tong and Furia estimated that the cost to treat plantar fasciitis in Medicare patients alone may be as high as $376 million a year.1
There is an evolving standard of care for the treatment of plantar fasciitis. With this in mind, let’s take a closer look at changing concepts in etiologic considerations, the diagnosis of plantar fasciitis, conservative management and surgical treatment.
Clinicians have long recognized overweight status as an etiologic factor in plantar fasciitis. Sadat noted a mean body mass index (BMI) of 30.36 in symptomatic patients in comparison to non-symptomatic patients with a mean BMI of 26.71.2 Similarly, Rano and colleagues relate an average BMI of 30.4 in heel pain patients in comparison to 28.2 in asymptomatic patients.3 These authors also noted no relationship between foot type and plantar fasciitis, but did observe that plantar fasciitis occurs more often in less active individuals. Riddle and colleagues noted that BMI was a major factor responsible for disability and functional impairment with heel pain.4 Given that heel pain is associated with increased BMI in many patients, a recommendation for weight loss is appropriate in this patient population.
There have been some advocates for changing terminology from plantar fasciitis to plantar fasciosis. This is based upon the work of Lemont and coworkers, who studied 50 histologic specimens from plantar fasciitis patients and found no evidence of an inflammatory process.5 The authors instead found myxoid degeneration, fragmentation of plantar fascia, degeneration of the plantar fascia and bone marrow vascular ectasia.
However, the presence of ultrasound demonstrable changes, such as resolved hypoechogenicity and decreased plantar fascia thickness, following the treatment of plantar fasciitis suggest the presence of a more active and dynamic process.6 Utilizing ultrasound, Fabrikant and Park demonstrated decreased plantar fascia thickness in response to injection and biomechanical therapy, again implying a more dynamic pathologic process.7 More recently, Mahowald and coworkers showed that changing thickness of the plantar fascia is a valid objective measurement to assess treatment protocols.8
Hafner and colleagues have also suggested a diverse etiology for plantar fasciitis in a study looking at 100 pathologic specimens in patients with recalcitrant plantar fasciitis.9 The authors found that 25 percent of patients demonstrated neoplastic changes consistent with plantar fibromatosis, 21 percent had inflammatory changes and 54 percent showed no inflammatory or neoplastic changes. Given these findings, the authors suggested that the etiology of plantar heel pain may be more diverse than frequently assumed and a more detailed evaluation may be appropriate in some patients.
A Closer Look At Biomechanical Considerations
Other authors have suggested that reduced foot mobility and decreased shock absorption may cause plantar heel pain as they demonstrated through assessment of nonweightbearing and weightbearing lateral radiographs of the foot, and measurements of calcaneal inclination, first metatarsal-calcaneal inclination and plantar fascia length.10 Researchers have also pointed to the decreased ability of the plantar fat pad to dissipate contact phase energy as being associated with plantar heel pain.11