Operative Techniques in Orthopaedic Surgery (4 Volume Set) 1st Edition

463. Endoscopic Plantar Fasciotomy

Steven L. Shapiro

DEFINITION

images Plantar fasciitis is the most common cause of heel pain in adults.

images The predominant symptom is pain in the plantar region of the foot when initiating walking.

images The cause is a degenerative tear of part of the fascial origin from the calcaneus, followed by a tendinopathy-type reaction.

ANATOMY

images The plantar fascia is a ligament with longitudinal fibers originating from the calcaneal tuberosity.

images The normal medial band is the thickest, measuring up to 3 mm.

images The central and lateral bands are 1 to 2 mm thick.1

images Distally, the plantar fascia divides into five slips, one for each toe.

images The plantar fascia provides support to the arch. As the toes extend during the stance phase of gait, the plantar fascia is tightened by a windlass mechanism, resulting in elevation of the longitudinal arch, inversion of the hindfoot, and external rotation of the leg.

images Endoscopically, the pertinent anatomy is the abductor hallucis muscle medially, then the plantar fascia. After fasciotomy, the flexor digitorum brevis comes into view as the medial intermuscular septum.

PATHOGENESIS

images Specimens of plantar fascia obtained during surgery reveal a spectrum of changes, ranging from degeneration of fibrous tissue to fibroblastic proliferation.

images The fascia is usually markedly thickened and gritty. These pathologic changes are more consistent with fasciosis (degenerative process) than fasciitis (inflammatory process), but fasciitis remains the accepted description in the literature.

NATURAL HISTORY

images The typical patient is an adult who complains of plantar heel pain aggravated by activity and relieved by rest.

images Start-up pain when initiating walking is common.

images Strain of the plantar fascia can result from prolonged standing, running, or jumping and activities that create repetitive stress on the plantar fascia. Excessive pronation is a common mechanical cause.

images The rigid cavus foot type can also predispose to plantar fasciitis.

images Obesity is present in up to 70% of patients.

images Plantar fasciitis is common among runners and ballet dancers.

images About 15% of cases are bilateral. Women are affected more than men.

PHYSICAL FINDINGS

images Localized tenderness over the plantar calcaneal tuberosity is the most common physical finding.

images Pain is usually medial, but occasionally lateral. Rarely, pain may be located distally; this condition is called distal plantar fasciitis. Frequently there is soft tissue swelling of the plantar medial heel.

images Careful comparison to the contralateral heel is useful in confirming tenderness typical for plantar fasciitis.

IMAGING AND OTHER DIAGNOSTIC STUDIES

images Radiographs are ordered routinely in patients with plantar heel pain.

images Plantar calcaneal spurs occur in up to 50% of patients but are not thought to cause heel pain; these are commonly associated with calcification in the origin of the flexor hallucis brevis, which is located proximal to the origin of the plantar fascia.

images Stress fractures, unicameral bone cysts, and giant cell tumors are usually identified with plain radiography.

images Three-phase technetium bone scans are rarely necessary but are positive in up to 95% of cases of plantar fasciitis.

images MRI can be used in questionable cases and elegantly demonstrates thickening of the plantar fascia and rules out soft tissue and bone tumors, subtalar arthritis, and stress fractures.

images Ultrasound is cost-effective and easily measures the thickness of the plantar fascia, documenting plantar fasciitis when thickness exceeds 3 mm.

DIFFERENTIAL DIAGNOSIS

images Plantar fascia rupture: Generally occurs acutely after vigorous physical activity. There may be visible ecchymosis in the arch. MRI or ultrasound confirms the diagnosis.

images Tarsal tunnel syndrome: Compression of the tibial nerve can cause numbness and pain in the heel, sole, or toes. Positive percussion and compression tests are elicited, and electromyography and nerve conduction studies are positive in 50% of cases.

images Distal tarsal tunnel syndrome, compression of the first branch of the lateral plantar nerve (Baxter's nerve), is often confused with plantar fasciitis and may be associated with plantar fasciitis. In fact, some surgeons recommend decompressing Baxter's nerve with every plantar fascia release. In our opinion, these two entities are separate, and with careful examination plantar fasciitis may be isolated and effectively treated with endoscopic plantar fascia release.

images Stress fractures: With a calcaneal stress fracture, tenderness is not localized to the plantar medial heel but instead is more diffusely present in the calcaneus, suggested by a calcaneal squeeze test. Plain films usually suggest a fracture line, but if there is any doubt, MRI clearly demonstrates stress fractures and readily distinguishes plantar fasciitis from stress fracture.

images Neoplasms: Visualized on plain films at times. MRI is diagnostic. Pain is typically achy, constant, nocturnal, and even present without weight bearing and at rest.

images Infection: Pain is often constant. There may be swelling, redness, or fluctuance. Plain films, MRI, or a white blood celllabeled scan can be diagnostic. Laboratory tests may show increased erythrocyte sedimentation rate, C-reactive protein, or white blood cells.

images Painful heel pad syndrome: Occurs most often in runners; thought to result from disruption of fibrous septa of the heel pad

images Heel pad atrophy: Occurs in the elderly, usually not characterized by morning pain, and a “central heel pain syndrome” with tenderness more plantar than in plantar fasciitis, directly under the bony prominence in the calcaneus

images Inflammatory arthritis: Usually bilateral and diffuse in nature. May be associated with positive RA, HLA, and B27 and an increased erythrocyte sedimentation rate.

NONOPERATIVE MANAGEMENT

images Conservative management includes rest, ice, nonsteroidal anti-inflammatories, plantar fascia and Achilles tendon stretching, plantar fascia-specific stretching protocols, silicone heel pads, prefabricated and custom orthoses, night splints, CAM walkers, casts, physical therapy, athletic shoes, judicious use of steroid injections, and shockwave therapy.

images Ninety-five percent of patients will respond to conservative management.

images Surgery is indicated after 6 to 12 months of conservative treatment.

SURGICAL MANAGEMENT

images Plantar fasciotomy is indicated in the few patients who fail to respond to conservative treatment.

images Although open techniques have yielded good results, endoscopic plantar fasciotomy (EPF) offers several important advantages:

images Minimal soft tissue dissection

images Excellent visualization of the plantar fascia

images

FIG 1 • Diagram of preoperative non–weight-bearing lateral radiograph showing appropriate measurements to identify the location of the medial portal incision.

images

FIG 2 • A second method to determine the placement of the medial incision. The incision is made along a line that bisects the medial malleolus 1 to 2 cm superior to the junction of keratinized and nonkeratinized skin.

images Precision in transecting only the medial third to half of the plantar fascia

images Minimal postoperative pain with early return to full weight-bearing status

images Earlier return to activities and work

Preoperative Planning

images Non–weight-bearing lateral radiographs of the affected foot are performed (FIG 1).

images A point just anterior and inferior to the calcaneal tubercle is marked and measurements are made to the inferior and posterior skin lines.2

images These measurements are used to select the incision site (FIG 2).

Positioning and Anesthesia

images The patient is positioned supine with a bump under the ipsilateral hip of the affected side to limit external rotation of the limb.

images

FIG 3 • Instratek Endotrac system for endoscopic plantar fasciotomy. From left to right: obturator with cannula, plantar fascia elevator, probe, disposable triangle knife with nondisposable handle, disposable hook knife with nondisposable handle, and disposable triangle knife without handle.

images The operative foot is then elevated on a foot prop with a tourniquet in place at the distal calf. The limb is prepared and draped in this position.

images We routinely order 1 g of cefazolin (Ancef) perioperatively.

images Anesthesia may be regional or general.

images We prefer an ankle block or popliteal nerve block with intravenous sedation.

images The procedure is performed on an outpatient basis.

Equipment

images The equipment required includes the Instratek Endotrac System (Instratek, Houston, TX), which consists of a plantar fascia elevator, cannula and obturator, probe, nondisposable knife handles, and disposable hook and triangle knives (FIG 3).

images We use a 4-mm 30-degree short arthroscope.

images Several cotton-tipped applicators lightly fluffed with a Bovie scratch pad are needed.

TECHNIQUES

SET-UP

images The foot is prepared and draped on the foot prop and then exsanguinated with an Esmarch bandage.

images The tourniquet is inflated at the distal calf to 250 mm Hg.

images Make an 8-mm vertical incision just anterior and plantar to the medial tubercle of the calcaneus.

images Use the measurements from the non–weight-bearing lateral film as a guide.

images A good landmark is the medial malleolus.

IDENTIFYING THE PLANTAR FASCIA ENDOSCOPICALLY

images The incision can be placed on a line dropped from the midpoint of the medial malleolus or the junction of the middle and posterior thirds of the medial malleolus.

images Portal placement is critical to the success of the procedure.

images Deepen the incision with blunt tenotomy scissors.

images Place the plantar fascia elevator through the incision and sweep it from medial to lateral just plantar to the plantar fascia.

images Pass the obturator and cannula through this pathway and bring them out through a lateral incision overlying the tip of the obturator.

images Remove the obturator from the cannula and clear the cannula of fat with cotton-tipped applicators (TECH FIG 1). The cannula should be perpendicular to the long axis of the foot.

images Bring the 4-mm 30-degree scope into the medial portal.

images Visualize the abductor hallucis muscle medially, and then the plantar fascia. Pass the probe from the lateral portal and advance it medially to palpate the medial band of the plantar fascia (TECH FIGS 2AND 3).

images

TECH FIG 1 • Clearing fat from cannula with fluffed cottontipped applicator to allow good visualization of the plantar fascia.

images

TECH FIG 2 • Intraoperative set-up with foot draped on foot prop, monitor on same side as foot, scope placed in cannula through the medial portal, probe through lateral portal. Plantar fascia is visualized on the monitor with the probe palpating the fascia.

images

TECH FIG 3 • Plantar fascia before fasciotomy as seen through cannula.

PLANTAR FASCIA RELEASE

images Remove the probe and advance the triangle knife to the medial band.

images Dorsiflex the foot to place tension on the plantar fascia.

images With a controlled motion, pull the triangle knife across the medial band of the plantar fascia (TECH FIG 4).

images Several passes are often necessary to completely divide this band.

images The flexor digitorum brevis muscle belly should be visible after the medial band is divided (TECH FIG 5). The fasciotomy is complete when the medial intermuscular septum is visualized.

images The amount of fascia divided is usually 14 mm, which can be measured off markings on the probe. The hook knife can be used to cut the fascia, but the triangle knife can be more easily manipulated with less likelihood of cutting into the muscle.

images

TECH FIG 4 • Endoscopic plantar fasciotomy performed with triangle knife as seen through cannula.

images

TECH FIG 5 • Flexor digitorum brevis muscle seen after endoscopic plantar fasciotomy. The central and lateral bands remain intact.

COMPLETION OF PROCEDURE

images After performing a partial fasciotomy, move the scope into the lateral portal to check if any bands of fascia remain uncut.

images The triangle knife can be passed through the medial portal to cut these bands.

images The two-portal system allows this versatility, which is lacking in the single-portal system.

images Irrigate the wound through the cannula.

images Reinsert the trocar and remove the trocar and cannula together.

images Close the incisions with 4-0 nylon.

images Apply a light dressing and posterior splint.

images Make prints, a CD, or both of preand postfasciotomy findings.

images

POSTOPERATIVE CARE

images Ice and elevation are recommended for 48 to 72 hours postoperatively.

images Minimal postoperative pain medication is required.

images Sutures are removed at 1 week postoperatively and a CAM walker, weight bearing as tolerated, is used for 3 weeks to minimize the risk of lateral column pain.

images Most patients can resume normal activities at 6 weeks postoperatively and vigorous athletic activities at 12 weeks postoperatively.

OUTCOMES

images All published literature on EPF reports greater than 90% success, with shorter recovery times than traditional open surgery. Our experience mirrors the literature, with no infections or nerve damage and only four instances of lateral column pain in over 400 cases in the past 11 years.

images The success rate of EPF is significantly higher than extracorporeal shockwave treatment. In addition, EPF is reimbursed by all insurance companies, whereas shockwave procedures still have erratic insurance reimbursement.

images EPF is minimally invasive, with a simple, easy-to-learn surgical technique. The equipment is minimal and cost-effective.

images The incision is only 8 mm, compared to open procedures, where the incision is at least 4 cm and, with some more extensile approaches, as much as 10 cm.

images Surgeons with prior arthroscopic experience should find EPF to be a straightforward procedure to master. DVDs and technique guides are readily available through Instratek.

images Training courses with cadavers are also given through the Orthopaedic Learning Center or Instratek. After 10 cases, the surgeon should feel confident with this procedure. With experience, average surgery time should be 10 to 15 minutes.

COMPLICATIONS

images Lateral column pain and arch pain have been the most common complications, reported in up to 3% to 5% of cases.

images Immobilization in a CAM walker for 4 weeks and limiting the division of the plantar fascia to the medial and central bands should reduce this complication even further.

images The Instratek system has single and double lines etched into the cannula to guide the surgeon to limit the plantar fasciotomy to 14 mm. The probe also has 1-cm markings. The disposable knives can also be marked with a marking pen to 14 mm. Using the intermuscular septum as a guide for where to stop the fasciotomy is probably the best anatomic reference as to where the central band ends and the lateral band begins.

images Infection rates are extremely low with EPF. We have had just one superficial wound infection (a diabetic patient) in over 400 cases.

images Injury to the medial and lateral plantar nerves is discussed extensively but rarely reported. Cadaver studies reveal a reasonable safe zone as long as the incision is appropriate.

images One case of pseudoaneurysm of the lateral plantar artery has been reported and a case of a cuneiform stress fracture. With appropriate technique and postoperative immobilization these complications should be rare.

REFERENCES

· Barrett SL, Day SV. Endoscopic plantar fasciotomy: preliminary studies with cadaveric specimen. J Foot Surg 1991;30:170–172.

· Barrett SL, Day SV. Endoscopic plantar fasciotomy two portal endoscopic surgical techniques: clinical results of 65 procedures. J Foot Surg 2004;32:248–256.

· Buchbinder R. Clinical practice: plantar fasciitis. N Engl J Med 2004;350:2159–2166.

· Hofmeister EP, Elliott MJ, Juliano PJ. Endoscopic plantar fascia release: an anatomic study. Foot Ankle Int 1995;16:719–723.

· Hogan KA, Weber D, Shereff M. Endoscopic plantar fascia release. Foot Ankle Int 2004;25:875–881.

· Sabir N, Debirlenk S, Yagzi B, et al. Clinical utility of sonography in diagnosing plantar fasciitis. J Ultrasound Med 2005;24: 1041–1048.

· Saxena A. Uniportal endoscopic plantar fasciotomy: a prospective study on athletic patients. Foot Ankle Int 2004;25:882–889.



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