Lengthening of Gastrocnemius Fascia

 

 

 

DEFINITION

Lengthening of gastrocnemius fascia is commonly performed for conditions in which the patient positions their foot in equinus either while standing or walking.

Equinus represents a loss of dorsiflexion and may be due to true shortening of the musculotendinous unit (myostatic contracture) and/or increased muscle tone or spasticity (dynamic contracture).

The most common condition in which this procedure is performed is cerebral palsy; however, other conditions include idiopathic toe walking, traumatic conditions, complications of surgical procedures such as tibial lengthening, and a variety of neuromuscular disorders.

Some disorders, such as Charcot-Marie-Tooth disease, may appear to have equinus, but the true deformity is plantar flexion of the midfoot on the hindfoot (midfoot cavus). Other disorders may have equinus that is less obvious due to a break in the midfoot and apparent dorsiflexion. The plantar flexion will be evident with correction of the midfoot.

Ankle equinus and midfoot cavus may also be observed in selected conditions.

 

 

ANATOMY

 

The medial and lateral heads of the gastrocnemius muscles, the soleus, and the plantaris muscles form the triceps surae. Although all are part of the same muscle group, their structure and function differ.

 

The larger medial head of the gastrocnemius arises from the popliteal surface of the femur just above the medial femoral condyle, and the lateral head originates from the superolateral surface of the lateral femoral condyle.

 

The medial and lateral muscle bellies insert into a midline tendinous raphe that widens into the aponeurosis of the gastrocnemius at or just above the midcalf.

 

This tendon unites with the soleus forms the conjoined tendon which inserts into the calcaneus by way of the tendo Achilles. A study of 40 cadavers indicated that there are five morphologic patterns identified at the “conjoint junction” or the place where the gastrocnemius tendon unites with the aponeurosis of the soleus.

These include transverse (25%), oblique passing distally and medially (45%), oblique passing distally and laterally (5%), arcuate as an inverted U (17.5%), and a U-shape (7.5%).5

 

As far as the location of the conjoint junction, Elson et al5 found that on the medial side, the gastrocnemius tendon could be located between 36% and 46% of the distance between the upper border of the calcaneus and the fibular head on the medial side, 45% to 58% in the midline, and 48% to 51% on the lateral side.

 

 

Pinney et al12 found that the gastrocnemius tendon was an average of 18 mm distal (20 to 57 mm) to the surface landmark of the distal aspect of the gastrocnemius muscle belly.

 

The gastrocnemius spans the ankle and knee joint and therefore can plantarflex the ankle and/or flex the knee. It typically has fast twitch type II muscle fibers, allowing for short, powerful bursts of activity, important in activities such as running and jumping.

 

The soleus lies deep (anterior) to the gastrocnemius muscle. It originates on the proximal tibia, fibula, and interosseous membrane, and its fascia blends with the tendon of the gastrocnemius to form the conjoined Achilles tendon or triceps surae. Contraction results in ankle plantarflexion. It is made up of primarily slow twitch type I muscle fibers. The soleus acts eccentrically to decelerate advancement of the tibia over the foot during the second rocker in stance phase and then concentrically during the push-off phase of gait.

 

The plantaris arises just above the lateral head of the gastrocnemius and inserts into the calcaneus; it is largely vestigial and should be released at the time of surgery.

 

PATHOGENESIS

 

Equinus positioning of the foot can occur due to the following:

 

 

 

Increased tone or spasticity of the triceps surae muscles Shortening of some or all of the muscles

 

 

Joint contracture Bony deformity

 

It is critical to differentiate the cause of the equinus because the treatment options differ in each circumstance.

 

The initiating etiology of this disorder varies. Spasticity, weakness, and subsequent shortening of the muscle group can occur, secondary to neuromuscular disorders such as cerebral palsy. Relative shortening of the triceps surae, as occurs when the tibia is lengthened, or fixed positioning of the foot in equinus, such as prolonged casting in plantar flexion, can all result in equinus of the ankle. Bony changes at the ankle due to trauma or congenital disorders may also result in equinus.

 

NATURAL HISTORY

 

The natural history varies according to each disease process and prior treatment history.

 

Equinus tends to progress in patients with cerebral palsy. The deformity begins as a dynamic loss of motion due to spasticity and then progresses to myostatic contracture. The contracted muscles may tether growth, resulting in skeletal deformities.

 

Equinus is also likely to progress in the majority of neuromuscular disorders.

 

Some disorders, such as idiopathic toe walking, often improve as the patient matures into adulthood.

 

 

 

PATIENT HISTORY AND PHYSICAL FINDINGS

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Patients may complain of tripping/falling due to inability to easily clear the limb during swing phase and/or pain over the metatarsal heads or forefoot from increased stress distribution over the forefoot.

 

Range of motion of the ankle should be assessed with the hindfoot inverted to lock the subtalar joint, avoiding spurious dorsiflexion through the transverse tarsal joints.

 

The Silfverskiöld test assesses the degree of passive ankle dorsiflexion with the knee flexed and extended. If dorsiflexion is restricted with the knee flexed, then there is contracture of the soleus. Loss of dorsiflexion when the knee is in extension indicates a contracture of the gastrocnemius.

 

Observational or instrumented gait analysis is important to correlate the physical finding with functional deficits during ambulation. The patient should be evaluated when walking and/or running.

 

Small limitations in dorsiflexion range may have little functional deficit.

 

 

Silfverskiöld test: The ankle should be able to be dorsiflexed 10 degrees. Observational gait analysis: rockers

 

 

First (heel): initial contact to loading response Second (ankle): midstance foot flat

 

Third (forefoot): terminal stance

 

IMAGING AND OTHER DIAGNOSTIC STUDIES

 

Although not routinely required, standing lateral radiographs of the foot may help to evaluate equinus, especially when there may be a component of midfoot cavus (FIG 1).

 

The angle between horizontal and a line drawn across the plantar aspect of the os calcis (calcaneal pitch) should be 15 degrees (0 and 30 degrees).

 

The angle between the line drawn through the tibia and along the distal articular surface of the tibia parallel to the measure 80 degrees (distal articular surface is dorsiflexed).

 

 

 

FIG 1 • Radiographic measures. Standard standing lateral radiographs of the feet. Angle A, the angle between the line drawn through the tibia and along the distal surface of the tibia should measure 80 degrees. Angle B, the angle between horizontal and a line drawn plantar aspect of the os calcis should be 15 degrees (0 and 30 degrees).

 

The contribution of the midfoot may be assessed by measuring the talo-first metatarsal angle (Meary angle).

DIFFERENTIAL DIAGNOSIS

Cerebral palsy, Duchenne muscular dystrophy, and other neuromuscular disorders

 

Idiopathic toe walking Congenital limb deficiencies

Bony deformity (posttraumatic, malalignment, asymmetric growth arrest) Postimmobilization

Posterior tibial lengthening

 

 

NONOPERATIVE MANAGEMENT

 

Physical therapy and stretching is the most common form of treatment for mild deformities and used in an attempt to maintain range when gained by other methods. The knee must be extended and the hindfoot placed in an inverted position when stretching the ankle.

 

Bracing and/or nighttime splinting can be used in combination with other techniques. It is primarily used to maintain gains or prevent worsening deformity.

 

Botulinum toxin (BTX) causes a reversible neuromuscular blockade by blocking acetylcholine release at the neuromuscular junction and can be considered as an adjunct to physical therapy and/or casting especially in

patients with spasticity. The effect lasts about 3 to 8 months.1

 

Serial casting10, 13 can also be used, in which short-leg casts are typically placed. They are changed weekly or biweekly, each time with increasingly greater dorsiflexion.

 

 

 

Usually, three or four casts are used until satisfactory range is obtained. Recurrence is common, and if not carefully performed, skin breakdown can occur.

SURGICAL MANAGEMENT

 

The gastrocnemius-soleus complex can be lengthened in a number of ways (FIG 2),2, 3, 4, 6, 7, 9, 11, 14, 15

depending on the following:

 

 

The degree of fixed shortening

 

 

Whether there is contracture of the gastrocnemius or both the gastrocnemius and the soleus Isolated lengthening of gastrocnemius fascia is indicated if

 

 

The gastrocnemius is selectively tight. This results in functional deficits.

 

Conservative (nonoperative) treatment has failed.

 

The gastrocnemius can be released from its origin on the femoral condyles (Silfverskiöld procedure), but this is rarely performed.

 

In this chapter, we focus on an isolated gastrocnemius recession, which is typically performed in zone 1 by either the Baumann-Koch technique3, 9, 14 or by the Strayer technique.12, 14, 15 The Baumann technique has also been referred to as an intramuscular lengthening, whereas the Strayer procedure has been termed a distal

gastrocnemius recession.

 

When the contracture involves both the gastrocnemius and the soleus muscles, techniques which lengthen both muscles are appropriate and these have also been termed gastrocsoleus aponeurotic lengthening. When the contracture is mild, either a zone 2 recession technique such as the

 

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Baker or Vulpius, or a “modified Strayer” procedure (additional cuts are made in the soleus fascia in zone 1), allow for additional lengthening.

 

 

 

FIG 2 • Procedures to lengthen the gastrocnemius-soleus complex can be described according to zones. Isolated gastrocnemius recession procedures are in zone 1 and include the Baumann and Strayer procedures. Recession techniques in which both the gastrocnemius and the soleus are lengthened, either selectively (Modified Strayer) or nonselectively (Vulpius, Baker), are in zone 2. Lengthening of the tendo Achilles itself occurs in zone 3 and involves either percutaneous or open techniques. (Adapted from Firth GB, Passmore E, Sangeux M, et al. Multilevel surgery for equinus gait in children with spastic diplegic cerebral palsy: medium-term follow-up with gait analysis. J Bone Joint Surg Am 2013;95:931-938.)

 

 

Lengthening at or below the conjoined tendon (ie, the tendo Achilles), in zone 3, lengthens the entire triceps surae. These techniques afford the most correction but also have the greatest risk of overlengthening, especially when performed as an isolated procedure.

 

Procedures in zone 2 carry a lesser risk of overlengthening but a greater chance of recontracture.

 

Zone 1 procedures have a very low risk of overlengthening but also have a significant risk of recurrence of contracture.

 

All of these recession techniques in which the gastrocnemius is lengthened, with or without the soleus, are commonly employed as part of a single-event multilevel surgery (SEMLS).

 

The intraoperative goal is approximately 5 degrees of ankle dorsiflexion. Judicious lengthening coupled with multilevel surgery should drastically reduce the incidence of crouched gait complicating tendo Achilles lengthening surgery.

 

Preoperative Planning

 

Planning should involve assessment of the entire patient, especially in patients with underlying neuromuscular disorders. Lower limb pathology commonly involves multiple levels, and the most appropriate plan usually involves addressing all of the abnormalities under a single anesthetic.

 

Isolated lengthening of gastrocnemius fascia in patients with cerebral palsy and tight hamstrings may be complicated by a crouch gait and should be avoided.

 

The Silfverskiöld test should be repeated under anesthesia. The surgeon should be prepared for additional procedures if lengthening of the gastrocnemius fascia alone does not result in sufficient dorsiflexion range.

 

Positioning

 

The patient can be positioned either prone or supine, depending on what other procedures are planned and the preference of the surgeon.

 

 

In the supine position, the limb must be externally rotated to gain access to the posterior medial calf, and it is easier to place a posteromedial incision than to do a direct posterior approach.

 

Similarly, some surgeons prefer a tourniquet, whereas others do not.

 

Approach

 

The incision for the Baumann procedure is made over the midcalf, about two fingerbreadths medial to the posteromedial edge of the tibia (FIG 3).

 

For the Strayer procedure, either a posteromedial or a posterior midline incision is made over the midposition of the lower leg, centered approximately 2 cm distal to where the distal muscle fibers of the gastrocnemius can be palpated.

 

The incision for the Vulpius and Baker are similar but should be centered several centimeters distal to that for the Strayer.

 

 

 

FIG 3 • Location of the incision, with the patient in the supine position.

 

 

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TECHNIQUES

• Baumann Procedure

The deep fascia is incised, exposing the gastrocnemius muscle, and the interval between the gastrocnemius and the soleus is developed bluntly (TECH FIG 1A).

 

 

 

 

TECH FIG 1 • A. Finger dissection is used to develop the plane in between the gastrocnemius and the soleus. B. Transverse cuts are made in the posterior fascia overlying the gastrocnemius muscle, whereas the ankle is dorsiflexed until normal Silfverskiöld test results are achieved. (Adapted from Herzenberg JE, Lamm BM, Corwin C, et al. Isolated recession of the gastrocnemius muscle: the Baumann procedure. Foot Ankle Int 2007;28:1154-1159.)

 

 

With a dorsiflexion force applied at the ankle, transverse cuts are made in the fascia overlying the gastrocnemius muscle until the desired degree of lengthening has been achieved (TECH FIG 1B).

 

The subcutaneous tissues and skin edges are closed in layers.

 

 

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• Strayer Procedure

   

  Dissection is carried down to the posterior fascia, which should not be confused with the gastrocnemius tendon.

   

  The saphenous vein must be protected medially and the sural nerve laterally (TECH FIG 2A).

   

  The deep fascia is divided and the underlying tendon is identified; often, the muscle bellies of the medial and lateral head of the gastrocnemius overlie the tendon and need to be carefully retracted (TECH FIG 2B).

   

  The tendon of the gastrocnemius is identified proximal to the conjoined tendon and is isolated by blunt dissection and carefully divided, avoiding injury to the underlying soleus muscle (TECH FIG 2C-F).

   

   

   

  TECH FIG 2 • The Strayer technique. A. Applied surgical anatomy. (Accurate incision size is shown in FIG 3 and TECH FIG 3A.) B. Exposure with the sural nerve identified. C. The fascia of the gastrocnemius exposed below the muscle belly. The tendon of the gastrocnemius is isolated with a hemostat (D) and divided with the soleus muscle (and its overlying fascia intact; E). F. Ankle range of motion is now increased to 10 to 15 degrees of dorsiflexion with the knee extended.

   

   

  The foot is dorsiflexed to the desired degree of correction and the tendon is sutured down to the underlying soleus fascia in its lengthened position, with the ankle in 5 to 10 degrees dorsiflexion with the knee extended.

   

  If the soleus is also found to be tight, then a modified Strayer (or Strayer with soleal fascial

  lengthening) may be performed by making a cut in the soleus fascia in zone1.7, 8, 11 In this scenario, a differential lengthening of both the gastrocnemius and the soleus is performed.

   

  The deep fascia can be repaired, followed by the subcutaneous tissue and a subcuticular closure on the skin. A short-leg cast is placed with the foot in neutral alignment.

   

   

   

• Baker Procedure

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  This technique involves a recession of the conjoined fascia involving the gastrocnemius tendon and the soleus fascia in zone 2 (TECH FIG 3A).

   

  An inverted U incision is made through the aponeurosis, the lateral and medial portions remain intact with the underlying soleus muscle (TECH FIG 3B).

   

   

   

  TECH FIG 3 • The Baker technique. A. Incision. B. The “box” cut in the gastrocnemius fascia. C. The lengthened tendon, with sutures placed. D. Baker procedure with the fasciae of the gastrocnemius and soleus divided, the muscle of the soleus is exposed.

   

   

  The foot is then dorsiflexed to achieve correction, and the central “tongue” will slide distally (TECH FIG 3C).

   

  After lengthening, the four corners of the overlapping portion of the tendon are secured with sutures (TECH FIG 3D).

   

  The closure and postoperative care are similar to the Strayer procedure.

   

• Vulpius Procedure

 

This technique is similar to the Baker technique, except that an inverted V incision is used to divide the conjoined fascia (TECH FIG 4A).

 

 

 

TECH FIG 4 • The Vulpius technique. A. Applied surgical anatomy. (Accurate incision size is shown in TECH FIG 3A.) The incision in the gastrocnemius is indicated by the dashed line. B. With the fasciae of the gastrocnemius and soleus divided, the muscle of the soleus is exposed.

 

 

More than one incision can be used if needed (TECH FIG 4B).

 

 

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PEARLS AND PITFALLS
	Indications ▪ Carefully examine to ensure that this is isolated gastrocnemius tightness. Assess the soft tissue at the hip and knee and treat coexisting pathology at these levels to avoid a “crouch gait.”     Positioning ▪ Patient position depends on surgeon's preference and what other procedures may be needed. Tourniquet control is helpful.     Avoid over- or ▪ The goal should be approximately 5 degrees of passive dorsiflexion with the underlengthening knee extended. If satisfactory dorsiflexion is not obtained, additional procedures may be required.

 

 

POSTOPERATIVE CARE

 

Although Strayer and Baker originally described a “toe-to-groin cast,” typically, a short-leg weight-bearing cast is worn for 4 to 6 weeks, with knee immobilizers to keep the knees extended when not ambulatory.

 

Care must be taken to avoid skin irritation when applying the necessary dorsiflexion, especially over the anterior ankle and the region of the metatarsal heads.

 

 

Consideration can be given to placing foam padding over the anterior ankle, metatarsal heads, and/or heel.

 

Bracing and nighttime splinting can be used to help maintain foot position.

OUTCOMES

Significant improvement in range of motion and dynamic joint motion during gait have been observed.

Little difference has been demonstrated between the different techniques for lengthening the fascia of gastrocnemius.

 

 

COMPLICATIONS

Lengthening of gastrocnemius fascia is generally a safe procedure with few complications.

Overlengthening of the triceps surae is considered to be less likely with this technique than by lengthening more distally at the Achilles tendon. Overlengthening may be complicated by a crouched gait pattern which is very difficult to treat.

Overlengthening is less likely when treatment of equinus is combined with other lower extremity procedures addressing soft tissue and bony pathology at multiple levels.

Injury to the sural nerve or saphenous vein is possible but uncommon and carries little long-term consequences.

Recurrence is the most common concern in the growing child especially when spasticity is present.

 

 

REFERENCES

1. Baker LD. A rational approach to the surgical needs of the cerebral palsy patient. J Bone Joint Surg 1956;38-A(2):313-323.

    

    

2. Baker LD. Triceps surae syndrome in cerebral palsy; an operation to aid in its relief. AMA Arch Surg 1954;68:216-221.

    

    

3. Baumann JU, Koch HG. Lengthening of the anterior aponeurosis of the gastrocnemius muscle [in German]. Operat Orthop Traumatol 1989;1:254-258.

    

    

4. Dreher T, Buccoliero T, Wolf SI, et al. Long-term results after gastroc-nemius-soleus intermuscular aponeurotic recession as a part of multilevel surgery in spastic diplegic cerebral palsy. J Bone Joint Surg Am

   2012;94:627-637.

    

    

5. Elson DW, Whiten S, Hillman SJ, et al. The conjoint junction of the triceps surae: implications for gastrocnemius tendon lengthening. Clin Anat 2007;20:924-928.

    

    

6. Etnyre B, Chamber CS, Scarborough NH, et al. Preoperative and postoperative assessment of surgical intervention for equinus gait in children with cerebral palsy. J Pediatr Orthop 1993;13:24-31.

    

    

7. Firth GB, McMullan M, Chin T, et al. Lengthening of the gastrocnemius-soleus complex: an anatomical and biomechanical study in human cadavers. J Bone Joint Surg Am 2013;95:1489-1496.

    

    

8. Firth GB, Passmore E, Sangeux M, et al. Multilevel surgery for equinus gait in children with spastic diplegic cerebral palsy: medium-term follow-up with gait analysis. J Bone Joint Surg Am 2013;95:931-938.

    

    

9. Herzenberg JE, Lamm BM, Corwin C, et al. Isolated recession of the gastrocnemius muscle: the Baumann procedure. Foot Ankle Int 2007;28:1154-1159.

    

    

10. Kay RM, Rethlefsen SA, Fern-Buneo A, et al. Botulinum toxin as an adjunct to serial casting treatment in children with cerebral palsy. J Bone Joint Surg Am 2004;86-A(11):2377-2384.

     

     

11. Novacheck T. Orthopaedic treatment of muscle contractures. In: Gage JR, Schwartz MH, Koop SE, et al. The Identification and Treatment of Gait Problems in Cerebral Palsy, ed 2. London: MacKeith Press, 2009:458.

     

     

12. Pinney SJ, Sangeorzan BJ, Hanson ST Jr. Surgical anatomy of the gastrocnemius recession (Strayer procedure). Foot Ankle Int 2004;25:247-250.

     

     

13. Pohl M, Rückriem S, Mehrholz J, et al. Effectiveness of serial casting in patients with severe cerebral spasticity: a comparison study. Arch Phys Med Rehabil 2002;83:784-790.

     

     

14. Shore BJ, White N, Graham HK. Surgical correction of equinus deformity in children with cerebral palsy: a systematic review. J Child Orthop 2010;4:277-290.

     

     

15. Strayer LM Jr. Recession of the gastrocnemius; an operation to relieve spastic contracture of the calf muscles. J Bone Joint Surg 1950; 32-A(3):671-676.