Endoscopic Plantar Fascia Release, Gastrocnemius Recession, and Intermetatarsal Nerve Decompression



Endoscopic Plantar Fascia Release, Gastrocnemius Recession, and Intermetatarsal Nerve Decompression


RANDY R. CLARK

PHINIT PHISITKUL

RICHARD D. FERKEL



Heel pain is one of the most common orthopedic complaints. One in 10 people will experience heel pain at some point in their life.1 Traditionally, most patients respond well to nonoperative treatment, but some patients fail conservative management and require surgical intervention. Heel pain can be caused by a variety of pathologies, but one of the most common reasons is plantar fasciitis. Plantar fasciitis-related heel pain is defined as isolated inflammation of the medial band of the plantar fascia. The symptoms have an insidious onset and are generally described as worse in the morning, after prolonged sitting, and after prolonged activity.2, 3, 4, 5, 6 Upon physical exam, the clinician will note focal tenderness of the plantar fascia at the medial calcaneal tuberosity and occasionally in the central portion of the plantar fascia. The examiner must consider and evaluate the patient for all causes of plantar heel pain. Appropriate workup may include additional diagnostic tests, such as magnetic resonance imaging (MRI), computer tomography (CT) scan, electromyography (EMG), nerve conduction velocity (NCV), and inflammatory arthritis screening labs.

Heel pain is also common among athletes. Traditionally, conservative management is an effective treatment, but occasionally surgical treatment is required and is successful in carefully selected patients.7

Eighty to ninety percent of patients with plantar fasciitis improve with conservative management including nonsteroidal anti-inflammatory drugs (NSAIDs), physical therapy, injections, casting, stretching, night splints, foot orthoses, and extracorporeal shock wave therapy (ESWT).8 The American Orthopedic Foot and Ankle Society (AOFAS) position statement with regard to heel surgery indicates that nonsurgical treatment is recommend for a minimum of 6 to 12 months. If surgery is advised, a patient should undergo a medical evaluation and be advised of the potential risks of surgery. If nerve entrapment is determined to be the cause of the heel pain, then an open decompression should be performed.9

The literature related to treatment of plantar fasciitis describes plantar fasciotomy, with or without excision of heel spurs.10, 11, 12 Controversy exists as to the amount of plantar fascia to release and still avoid disrupting the windlass mechanism and longitudinal arch of the foot.


ENDOSCOPIC PLANTAR FASCIA RELEASE

Surgeons employ open and endoscopic techniques to release the plantar fascia. While open techniques have proven effective, potential associated problems include injury to the medial calcaneal nerve, prolonged healing, and necessity for postoperative immobilization in order to protect the incision and allow for healing. Kinley et al. reported that patients who undergo endoscopic plantar fascia release (EPFR) had significantly less postoperative pain, returned to regular activities 4 weeks earlier, and had fewer complications.13 Some authors have suggested EPFR is an option to prevent the previously described morbidities.13, 14, 15, 16, 17 Morag et al. indicated that EPFR may decrease complications as compared to open techniques due to less disruption of a tenuous hindfoot blood supply.18


Anatomy

The plantar fascia can be palpated in the longitudinal arch and traced proximally from the distal insertion of the metatarsal heads and proximal phalanges to its origin on the medial calcaneal tuberosity of the os calcis. In some patients, the plantar fascia is connected to the Achilles tendon by a continuous fascial connection on the posterior and deep aspect of the calcaneus. The plantar fascia lies deep to the subcutaneous tissues and superficial to the intrinsic muscles of the foot. It has medial, central, and lateral components or bundles. The important medial flexor tendons and neurovascular bundle lie deep to the plantar fascia (Fig. 19-1).







FIGURE 19-1. The medial side of the foot, showing the flexor retinaculum, plantar fascia, and neurovascular bundle. (Illustration by Susan Brust.)

The plantar fascia is a critical structure for arch stability. The dynamic relationship of the plantar fascia and midfoot joints is often referred to as the “windlass mechanism.” Due to the anatomic relationships of the plantar fascia, the posture of the arch and its distal insertion into the plantar plates of the metatarsophalangeal joints, dorsiflexion causes the plantar fascia to tighten. This dynamic relationship accentuates the arch and redirects weight-bearing forces across the midfoot joints and decreases sheer stress across the foot19 (Fig. 19-2A, B).






FIGURE 19-2. Windlass mechanism. (A) During the midstance phase of gait, the foot is shown in pronation with the medial arch flattened with weight acceptance. The plantar fascia prevents further flattening of the arch and redirects the force across the axis of the bones. (B) Foot shown in supination during the propulsive phase of gait. The midfoot and hindfoot compress and become rigid, tightening the plantar fascia. (Illustration by Susan Brust.)



Instrumentation and Portals

There are a variety of instrument sets that can be used to release the plantar fascia, including those made for carpal tunnel release. The author uses the Endotrac Endoscopic Plantar Fasciotomy instrumentation set. The technique includes an internally marked, slotted cannula, which allows visualization of the plantar fascia, and hook and triangular knives to release the plantar fascia. The set contains an obturator, laser marked cannula, fascial elevator, fascial
probe, blade handles, and disposable blades (Fig. 19-3). The system is compatible with a standard 4.0-mm, 30° scope or smaller.








Table 19-1. Differential Diagnosis for Heel Pain













Soft tissue


Plantar fascia rupture


Enthesopathies


Fat-pad atrophy


Achilles tendinitis


Flexor hallucis longus tendinitis


Plantar fibromatosis


Posterior tibial tendinitis


Heel contusion


Retrocalcaneal bursitis


Abductor digiti quinti nerve entrapment


Spring ligament injury


Neurologic


Tarsal tunnel syndrome


First branch of the lateral plantar nerve entrapment


Medial calcaneal nerve entrapment


Peripheral neuropathy


S1 radiculopathy


Charcot/neuropathic arthropathy


Skeletal


Calcaneal stress fracture


Calcaneal epiphysitis (Sever disease)


Bone contusion


Infections (osteomyelitis/subtalar pyarthrosis)


Subtalar arthritis


Inflammatory arthropathies


Arthritis or instability of the midfoot joints


Metabolic disorders


Osteomalacia


Paget disease


Sickle cell disease


Tumors


Lumbar spine disorder







FIGURE 19-3. EPFR instrumentation includes (from left to right) an obturator, laser marked cannula, fascial elevator, fascial probe, and blade handles.






FIGURE 19-4. The 4.0-mm 30° arthroscope (as seen above) used for EPFR as compared to the arthroscope (as seen below) commonly used in knee and shoulder arthroscopy.

The portals for the EPFR depend on the technique and instrumentation system. There are options for single- and double-portal techniques. The EPFR relies on the same instrumentation and arthroscope (endoscope) as does carpal tunnel release. The 4.0-mm 30° arthroscope used for this procedure is similar to the arthroscope commonly used in knee and shoulder arthroscopy, but its length is just 100 mm as compared to usual 157 mm (Fig. 19-4). The arthroscope is also unique because the bevel is directed toward the light cord, instead of away from it (Fig. 19-5).

The single-incision technique is performed with a single plantar medial portal and utilizes an arthroscope that has a separate instrumentation channel attached to it.

The two-incision technique uses medial and lateral portals. The medial portal is made by extending a line distally along the posterior aspect of the medial malleolus, which
generally intersects the medial origin of the plantar fascia at the medial calcaneal tuberosity (Fig. 19-6A, B). Dissection superficial to the fascia allows a blunt cannula to be placed transversely across the heel to establish the lateral portal. The medial calcaneal branch of the lateral plantar nerve is 8 to 10 mm posterior to the medial portal. The lateral plantar artery and nerve are 7 mm distal to the most medial aspect of the plantar fascia.17






FIGURE 19-5. Unique bevel of the arthroscope directed toward the light cord, instead of away from it.






FIGURE 19-6. Establishing the medial portal in a right hindfoot. (A) The anatomy underlying the medial incision; notice the branches of the posterior tibial nerve. Care is taken to avoid injuring the medial calcaneal and lateral plantar nerves with the medial portal. (B) The medial portal is made by extending a line distally along the posterior aspect of the medial malleolus, which generally intersects the medial origin of the plantar fascia at the medial calcaneal tuberosity. (Illustration by Susan Brust.)

Hofmeister et al. indicated that with a medial incision approach, the average amount of plantar fascia released is 81%. The average distance of the release to the lateral plantar nerve and the nerve to the abductor digiti minimi was 10.5 and 12.3 mm. They also indicated that the flexor digitorum brevis (FDB) is partially transected in 46% of the cases. They concluded, as did Reeve et al., that EPFR is effective and safe.20, 21 Hawkins et al. performed a cadaveric study to evaluate the surgical technique in relation to the neurovascular structures. They found that the first branch of the lateral plantar nerve was never at risk.22


Author’s Preferred Technique

The procedure is done as an outpatient. A popliteal block is performed by the anesthesiologist prior to administration of general anesthesia. The patient is positioned supine on the operating table, and a tourniquet is used to improve visualization during the procedure (Fig. 19-7).

The operative leg is prepped and draped in the standard fashion. The senior author prefers to sit at the medial foot of the table with an assistant seated lateral to the operative leg. The monitor is placed at the foot of the bed, in order for the team to easily visualize it. The instruments are placed on a Mayo stand within immediate reach of the surgeon (Fig. 19-8).

A vertical medial incision is made through the skin only, and a hemostat is used to bluntly dissect the subcutaneous tissue to the level of the medial edge of the plantar fascia. This is done in order to avoid injury to the posteriorly
located calcaneal nerve branch. The fascial elevator clears the pathway for the arthroscope being careful to stay plantar to the plantar fascia (Fig. 19-9). A blunt trocar is then passed through this medial portal or channel and identified pressing against the lateral skin (Fig. 19-10). The trocar position is critical. It should be placed parallel to the floor without angulation from the medial portal (Fig. 19-11A, B).






FIGURE 19-7. Note the patient/surgeon positioning and operative setup.






FIGURE 19-8. The primary surgeon sits at the medial foot of the table with an assistant seated lateral to the operative leg. Instruments are placed on a Mayo stand within immediate reach of the surgeon.

A second vertical incision is made directly over the trocar on the lateral aspect of the foot. The slotted cannula is then inserted over the trocar through the lateral portal, and the endoscope is introduced through the lateral aspect of the cannula with the slot open to the plantar fascia (Fig. 19-12A, B). Cotton swabs are passed through the cannula to remove fluid and debris from the visual field. A probe is then placed through the medial portal and used to determine the length of the entire plantar fascia. The medial third to half of the plantar fascia is measured; a mark is made on the probe and endoscopic knives to prevent releasing the plantar fascia too far laterally (Fig. 19-13).

The ankle and foot including the toes are dorsiflexed in order to place tension on the plantar fascia. The premarked probe is inserted in order to palpate the plantar fascia (Fig. 19-14). A triangular knife blade is then inserted through the medial portal, and an incision is made at the lateral border of the intended fasciotomy (Fig. 19-15A, B). A hook knife is then introduced into the cannula, and the plantar fascia is released from lateral to medial (Fig. 19-16A-C). An appropriate release can require several passes, and care should be taken to incise the fascia in its entirety but avoid injury to the underlying muscles. After the plantar fascia is released, the underlying intrinsic muscles, including the FDB, will bulge out slightly (Fig. 19-16D, E). The endoscope is then passed medially and deep within the plantar fascia incision to visualize part of the deep fascia of the abductor hallucis muscle. A hook blade is then used to release the deep fascia of the abductor if it is well visualized. During this maneuver, the surgeon must consider the potential of lateral plantar nerve injury; thus the knife must be seen and confined to passage within several millimeters from medial to lateral.






FIGURE 19-9. Use of the fascial elevator to clear the pathway for the arthroscope. It is critical to stay plantar to the plantar fascia.






FIGURE 19-10. A blunt trocar is passed through the medial portal.

After completing the release, the wounds are irrigated and closed with 4-0 nylon sutures. A compression dressing is applied, and the patient is placed into a short leg cast at neutral dorsiflexion or a removable boot for 4 weeks. Weight bearing begins gradually with crutches and is increased as tolerated. At 1 month, the patient may transition into a supportive shoe with orthotics and start stretching and strengthening activities.17

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Sep 25, 2018 | Posted by in RHEUMATOLOGY | Comments Off on Endoscopic Plantar Fascia Release, Gastrocnemius Recession, and Intermetatarsal Nerve Decompression
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