Point-Counterpoint: Recalcitrant Plantar Fasciitis: Is Fasciotomy Ever Necessary?
Plantar fasciitis is one of the most common disorders presenting to podiatric practices today. The mechanical forces that occur during all weightbearing activities cause the chronic plantar heel pain from plantar fasciitis. These forces act directly on the plantar calcaneus and on one of the most important supporting structures of the plantar foot, the central component of the plantar aponeurosis.1
The central component is the most important of the three components of the plantar aponeurosis. The medial component acts as the thin covering of the abductor hallucis muscle. The lateral component inserts upon the base of the fifth metatarsal but is only present in 92 percent of the population.2 From its origin on the plantar aspect of the medial calcaneal tubercle, the central component of the plantar aponeurosis fans out distally to insert onto the sesamoids and plantar plates of the metatarsophalangeal joints (MPJs), which attach by ligaments to the plantar bases of the proximal phalanges of all five digits.
In effect, the central component of the plantar aponeurosis is the longest and strongest plantar ligament of the longitudinal arch. It provides structural support to the foot from the plantar heel to the plantar digits by helping to prevent lengthening and flattening of the longitudinal arch of the foot.3
The majority of cases of plantar fasciitis result from the combination of the tensile force from the central component of the plantar aponeurosis and the compression force from ground reaction force (GRF) acting on the origin of the central component of the plantar aponeurosis at the plantar calcaneus.1 The combination of these forces pulls and pushes on the same small area of the plantar calcaneus with every step.
Since it is these tension and compression forces that damage the tissues of the plantar calcaneus and cause the pain from plantar fasciitis, it is mechanically reasonable that podiatric physicians should design their treatments for plantar fasciitis around reducing these pathological tension and compression forces. Doing so will allow the plantar calcaneus to heal itself and thereby resolve the patient’s chronic plantar heel pain.
Therefore, the goal of treatment for plantar fasciitis should be to reduce both the tensile force from the plantar fascia and the compression force from ground reaction force acting on the plantar calcaneus.1 Most of the standard accepted treatments for plantar fasciitis focus on accomplishing these mechanical goals.
Reducing weightbearing activities, using immobilization bracing or casting, avoiding barefoot walking, and using prefab or custom foot orthoses all reduce these forces acting on the plantar heel.4-6 Calf stretching reduces the tensile stiffness within the Achilles tendon and gastrocnemius-soleus muscles, which will in turn reduce the tension force within the central component of the plantar aponeurosis.7-9 Plantar strapping reduces the length of the medial longitudinal arch, which helps unload the central component of the plantar aponeurosis.10 Plantar arch massage and night splints likely reduce plantar fascial tension by temporarily lengthening the plantar fascia.
Other common therapeutic modalities such as icing, nonsteroidal anti-inflammatory drugs, iontophoresis and cortisone injections are all also in common use to reduce the discomfort associated with plantar fasciitis.11
Why The Plantar Fasciotomy May Lead To Negative Biomechanical Effects
The majority of patients respond well to these therapeutic measures so the pain from plantar fasciitis gradually resolves. However, a small percentage of patients with plantar fasciitis may show little to no response with standard conservative therapeutic measures for their chronic plantar heel pain. When it comes to these patients, who have chronic plantar heel pain despite a long course of conservative treatment, the podiatric surgeon may consider partial plantar fasciotomy as a surgical approach. The fasciotomy could reduce one of the major pathologic forces acting on the plantar calcaneus, the tensile force from the central component of the plantar aponeurosis.