18 Plantar Fasciectomy and First Branch Lateral Plantar Nerve Release Abstract Plantar fasciitis is one of the most common orthopaedic conditions affecting the hindfoot. Patients complain of excruciating heel pain, especially with the first step in the morning, that tends to resolve throughout the day with walking and tenderness to palpation of the plantar foot. This pain is related to repetitive tensile stresses on the plantar fascia. Many of these patients also complain of neuritic pain that is associated with impingement of the first branch of the lateral plantar nerve, or Baxter’s nerve, as it traverses deep to the abductor hallucis. This combination of pathology has been described as distal tarsal tunnel syndrome in the literature. Nonsurgical, conservative therapy is the treatment of choice for plantar fasciitis and this condition. After conservative treatments fail, patients can elect for surgical intervention. In this chapter, we describe the benefits of a partial plantar fasciectomy and release of Baxter’s nerve. Prior to surgical intervention, it is critical for the surgeon to obtain a detailed history and physical examination to determine the nature and origin of the heel pain. With the guidance of imaging modalities, the surgeon can more reliably identify potential sources of pain that can help guide surgical management. This surgical intervention provides definitive treatment of plantar fasciitis and nerve impingement and can provide pain relief and a gradual return to daily and recreational activities. Keywords: recalcitrant plantar fasciitis, plantar fasciectomy, Baxter’s nerve release, first branch of lateral plantar nerve, distal tarsal tunnel syndrome • Chronic degenerative condition at the origin of the plantar fascia on the medial calcaneal tuberosity. • Repetitive microtrauma and injury-reparative processes lead to micro-tears, necrosis, and chondroid metaplasia. • Traction irritation of the first branch of the lateral plantar nerve (Baxter’s nerve) as it traverses under the deep fascia of the abductor hallucis and over the superficial fascia of the quadratus plantae. • Neuropathic pain due to compression of Baxter’s nerve is referred to as “distal tarsal tunnel syndrome.”1 • Repetitive tensile forces on the plantar fascia with dorsiflexion of the ankle and metatarsophalangeal (MTP) joints during toe-off (windlass mechanism). • Radiation of neuritic pain along lateral aspect of the plantar heel. • Tight Achilles tendon complex and restricted ankle dorsiflexion. • Severe morning heel pain, especially when taking the first step. • Resolution of pain with stretching and walking, and throughout the day. • Worsening pain when barefoot or with flat shoes due to decreased medial longitudinal arch support. • Two primary sources of pain on physical examination: • Positive Tinel’s sign with radiating pain in the distribution of the first branch of the lateral plantar nerve (lateral plantar foot, lateral fourth toe, and fifth toe). • Pain on passive toe dorsiflexion (tension on the plantar fascia): • X-ray: lateral weight-bearing views of the affected foot: • Electromyogram (EMG): • Magnetic resonance imaging (MRI): sensitive for frank rupture of plantar fascia but not indicated in most cases: • Relative rest from exercise. • Stretching of plantar fascia, Achilles tendon, and gastrocnemius/soleus complex. • Semi-rigid, triple-layered orthotic devices for arch support and heel cup cushioning. • Night splinting with dorsiflexion. • Nonsteroidal anti-inflammatory drugs. Fig. 18.1 Sagittal T1-weighted suppressed image of the right foot. The image demonstrates high signal demonstrating thickening of the plantar fascia and adjacent edema in the subcutaneous fat tissue. • Extracorporeal shock wave lithotripsy therapy. • Cortisone injection at medial calcaneal tuberosity if persistent pain. • Cold therapy. • Nonsurgical therapy is the treatment of choice for patients with less than 6 months of symptoms. • Surgical intervention is considered only if patients are refractory to conservative measures or symptoms last more than 6 months. The purpose of surgical intervention for recalcitrant plantar fasciitis and nerve impingement is to relieve pain refractory to conservative options. Alleviation of or decreased heel pain can effectively improve functional limitations in daily and recreational activities. The primary advantage of surgical resection of the plantar fascia and release of the first branch of the lateral plantar nerve is definitive treatment. Fasciectomy of at least one-third of the medial band of the plantar fascia has been demonstrated to yield the most patient satisfaction with heel pain relief.6 The release of the nerve relieves pain and paresthesia associated with nerve compression. This procedure addresses the two primary sources of pathology related to plantar fasciitis and can provide definitive treatment of the disorder. • Incision of one-third to one-half of the medial band of the plantar fascia.6 • Avoid overexcision of the medial or central band of the plantar fascia, given that complete resection is associated with dorsal foot pain. • Baxter’s nerve dissection between the deep fascia of the abductor hallucis and the superficial fascia of the quadratus plantae. • Complete release of the deep fascia of the abductor hallucis to allow for gliding of Baxter’s nerve. • Avoid over-dissection of the calcaneal branches of the posterior tibial nerve. • Excision of an existing calcaneal spur is not necessary. The patient is placed on the operating room table in the supine position with the affected lower extremity in extension and external rotation. A bump can also be placed under the contralateral hip to allow for full external rotation. Regional anesthesia via a popliteal nerve block is recommended, and an ipsilateral calf tourniquet can improve intraoperative visualization. Using a surgical marker, the medial malleolus is outlined and a straight line is drawn from the heel to the posterior malleolus. The midpoint is marked between the posterior border of the medial malleolus and the medial border of the Achilles. The medial edge of the heel is palpated posteriorly and distally to feel for the “soft spot” where the neurovascular bundle is located. This area is marked as well for orientation. These superficial landmarks help delineate the medial oblique incision to be made from the origin of the abductor hallucis to the plantar foot (Fig. 18.2).
18.1 Indications and Pathology
18.1.1 Clinical Evaluation
Pain or point tenderness at the medial calcaneal tuberosity.
Medial hindfoot tenderness at the origin of the abductor hallucis due to compression of Baxter’s nerve traversing underneath.
Also demonstrated in S1 radiculopathy, but patients will lack localized tenderness at the plantar heel.
18.1.2 Radiographic Evaluation
To rule out calcaneal stress fracture or hindfoot degenerative joint disease.
May demonstrate plantar spur at the calcaneal origin of the flexor digitorum brevis but is not considered a reproducible source of pain.2,3
Abnormalities of abductor hallucis and/or abductor digiti minimi due to compression of Baxter’s nerve.4
May also demonstrate S1 radiculopathy in the lateral plantar foot.
Selective atrophy of abductor digiti minimi indicated by high-signal areas in T1-weighted and low-signal areas in T2-weighted images (Fig. 18.1).5
Focal thickening of plantar fascia with edema.5
18.1.3 Nonoperative Options
18.1.4 Contraindications
18.2 Goals of Surgical Procedure
18.3 Advantages of Surgical Procedure
18.4 Key Principles
18.5 Operative Technique
18.5.1 Preoperative Preparation and Patient Positioning
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