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Combined lengthening of the plantar flexors of the ankle and foot for equinus gait in cerebral palsy
The Foot (1994)
4, 136-144
Combined lengthening of the plantar flexors of the ankle and foot for equinus gait in cerebral palsy T. Matsuo, N. Kawada, 0. Tomishige Department of Orthopaedic Surgery, Shinkoen Hospital for Handicapped Children, Fukuoka, Japan S UMMA R Y. 92 patients with equinus deformity treated by combined gastrocnemius aponeurotic lengthening, intramuscular lengthening of the peroneus longus and tabialis posterior, and sliding lengthening of the flexor hallucis longus and flexor digitorum longus either with or without concomitant Achilles tendon lengthening were reviewed an average of 4.2 years after operation. In 79.4% of the cases, the clinical results were satisfactory, including 41 excellent, 31 good and 20 poor outcomes. There were improvements in the range of motion, gait pattern and ambulatory capability. 18 feet with severe deformities had a poor result with a recurrence of equinus and equinovarus deformities. 2 of 21 feet with concomitant Achilles tendon lengthening had a poor result with a calcaneal gait.
Equinus is the most common deformity in patients with cerebral palsy and stable weightbearing is impaired as a result of a decrease in the support at the base of the foot. Hyperactivity of the plantar flexors is generally the major cause of this deformity. To correct this deformity, various procedures have been describedIm Achilles tendon lengthening has been widely used,2,4,5 but the postoperative results still leave much to be desired. When the triceps surae is lengthened too much, the push-off power weakens and stable weightbearing is no longer feasible.6 The use of a brace is often necessary to overcome the weakness in the plantar flexors. Conversely, when the lengthening is insufficient there will be a recurrence. Bleck has previously discussed which operation offers the best compromise between relieving the contracture and preserving the strength.4 Gastrocnemius aponeurotic lengthening was designed to lengthen the gastrocnemius and to spare the soleus muscle and has been reported by Baker & Hill’ and Strayer.7 The objective of this procedure is to relieve spasticity and to preserve strength. The results have been satisfactory with respect to the preservation of stability, 6,8*9however, the recurrence rate has remained high.’ In an attempt to overcome these problems, we directed our attention to the hyperactivity of other plantar flexors, such as the peroneus longus and tibialis posterior, as a cause of the deformity, and designed a combined release operation which involves the intramuscular lengthening of these muscles. lo The details of this operation are herein described, and the muscular factors leading to equinus deformity, as well as the surgical techniques used
to control the hypertonicity also discussed.
of these muscles, are
MATERIALS AND METHODS Patients Between May 1983 and December 1989, 143 feet with equinus deformity in 102 patients were treated with combined lengthening, including fractional lengthening of the tibialis posterior and peroneus longus, sliding lengthening of the flexor hallucis longus and digitorum longus, and aponeurotic lengthening of the gastrocnemius. Of these, 92 feet of 63 patients could be followed and their related activities were monitored. 5 patients (5 feet) were diagnosed as cases of spastic monoplegia, 14 (14 feet) as cases of spastic hemiplegia, 43 (72 feet) as cases of spastic diplegia, and 1 (1 foot) as a case of spastic triplegia. 2 patients (3 feet) with tension athetosis were excluded from the analysis. 53 patients were ambulatory, 2 were ambulatory with crutches, 5 were ambulatory with the use of a walker and 3 were able to stand with selfsupport. Children at the non-sitting level, propped sitting level, and sitting level were excluded from the evaluation in this study. The ages at the time of surgery ranged from 3 to 19 years, with an average of 9 years and 1 month. All patients were followed for an average of 4.2 years, range 2-8.3 years. The combined surgery in the lower extremities included a lengthening of the psoas as well as a proximal lengthening of the hamstrings in 33 hips and a distal lengthening of the hamstrings in 4 knees.l’*” All treatment and follow-up procedures were carried 136
Combined lengthening of the plantar flexors of the ankle and foot for equinus gait in cerebral palsy
out at the Shinkoen Hospital Children, Fukuoko, Japan.
for
Handicapped
Method
A longitudinal incision is made over the medial side of the Achilles tendon. The tendon of the flexor hallucis longus and flexor digitorum longus are lengthened, using sliding technique. At the distal third of the medial aspect of the calf, the tibialis posterior is identified and the musculotendinous junction of the tibialis posterior is lengthened using fractional lengthening (Fig. 1). At the one-half level of the lateral aspect of the calf, the musculotendinous junction of the peroneus longus is visualized and then lengthened (Fig. 2). Care must be taken not to lengthen the peroneus brevis tendon which is located just anterior to the peroneus longus. Over the middle of the calf, the aponeurotic tendon of the gastrocnemius and soleus is divided just distal to the gastrocnemius muscle. In the case of a moderate to severe deformity, the aponeurosis at the 2-4 cm distal level is also sectioned. In the case of a severe deformity, the Achilles tendon is carefully lengthened to the desired length using a sliding technique (Fig. 3). A cast is applied from the groin to the toes, with the knee in moderate flexion and the foot in a slight plantarflexion for 2-3 weeks in cases of aponeurotic lengthening of the gastrocnemius. In cases with
137
Achilles tendon lengthening, fixation is extended to 6 weeks. An orthosis is used for 2-3 months for a foot with Achilles tendon lengthening. A night splint is not necessary. Evaluation
To determine the extent of the lengthening and to evaluate the results of this surgical repair, the passive range of motion of the ankle is measured. Gait pattern, clinical assessment according to Kling’s evaluation and the ambulatory capability is also evaluated.13 Passive dorsiflexion
With the knee extended and the foot in a neutral position, passive dorsiflexion of the ankle (dorsiflexion with knee extension, DKE) is measured. With the knee flexed, passive dorsiflexion of the ankle (dorsiflexion with knee flexion, DKF) is measured. The feet in which DKE is more than -10” was categorized as mild deformity; those in which DKE is between - IO” and -25”, as moderate; and those in which DKE is less than -25”, as severe. Gait pattern
To assess dynamic deformity during gait, the gait pattern was used. The categories of the gait pattern include a heel-toe gait, a flat foot gait, a toe-heel
Flexor digitorum
I
posterior
longus
\\
tibia1 vessels
I
Fractional lengthening
-a -.
^L, ,,,,d
I’\’ ,l>
’
\
Tibialis posterior
Fig. l-Intramuscular lengthening of the tibialis posterior. A longitudinal incision is made on the distal third of the medial aspect of the calf. Retracting the soleus and the tibia1 vessels and nerve posteriorly and the flexor digitdrum longus medially, the musculotendinous junction of the tibialis posterior is identified and then lengthened using the fractional technique.
,Peroneus
’ Fractional
longus
lengthening \
Peroneus
brevis
Fig. 2-Intramuscular lengthening of the peroneus longus. On the one-half of the lateral aspect of the calf, the musculotendinous junction of the peroneus longus is lengthened using the fractional technique. The peroneus brevis located just anterior to the peroneus longus is carefully protected since it is an important dorsiflexor.
Gastrocnemius
Sliding lengthenin
Fig. 3-Heel cord lengthening and gastrocnemius aponeurotic lengthening. (A) Sliding lengthening of the Achilles tendon. After the Achilles tendon is exposed, two plastic tubes are inserted under the tendon. An absorbable suture is inserted. One half of the Achilles tendon is cut above the posterolateral aspect and one half is cut below the medial aspect. Passive dorsiflexion of the ankle results in sliding lengthening. Fixation with the inserted suture is important to prevent any postoperative overlengthening. (B) Aponeurotic lengthening at the proximal level. Tendons of the gastrocnemius and soleus are incised at the level just distal to the gastrocnemius muscles. (C) Aponeurotic lengthening at the distal level. Tendons of the gastrocnemius and soleus are lengthened using aponeurotic lengthening at the level 2-3 cm distal to the gastrocnemius muscles.
Combined lengthening of the plantar flexors of the ankle and foot for equinus gait in cerebral palsy
gait, a toe gait, a toe cavus gait and a calcaneal gait. In the heel-toe gait, there is a gait with heel contact and toe-off pattern. In the flat foot gait, plantigrade foot is accomplished but no heel contact and toe-off pattern is seen. In the toe-heel gait, weightbearing is made on the forefoot, but there is only temporary heel contact. In the toe gait, weightbearing is made only on the forepart of the foot. In the toe cavus gait, the gait includes a toe gait with a marked cavus deformity. In the calcaneal gait, a gait with calcaneus deformity is present and the forward leaning of the tibia in the stance phase is over 15”. Clinical evaluation (Kling’s)
The rating system of Kling et ali3 was used to categorize the clinical results. Patients who walked with a plantigrade foot, without any fixed or postural deformity in regular shoes and had normal callosities, had excellent results. They did not need an orthosis postoperatively and were pleased with the results. Children who walked with less than 5” of varus, valgus or equinus posture of the foot, wore regular shoes with no abnormal shoe wear, had normal callosities, and who were satisfied with the outcome, had good results. Those whose feet had a recurrent equinus deformity or were overcorrected into a calcaneus deformity had poor results. Ambulatory capability
In order to compare pre- and postoperative stability, the ambulatory capability of each patient without a brace was evaluated, according to the modified Hoffer’s evaluation.14 A numerical grade was assigned to each class: grade 1, non-ambulator (wheelchairbound patients, those who are only able to stand when moving from bed to chair); grade 2, nonfunctional ambulator (wheelchair-bound patients, those who are able to walk with the use of walker on a level floor); grade 3. household ambulator with crutches (those who are able to walk short distances within the home); grade 4, community ambulator with crutches (those who are able to walk outdoors with the use of crutches; wheelchair only needed for long distances); grade 5, household ambulator without crutches (those who are able to walk within the home without the use of crutches and braces; crutches only needed for long distances); and grade 6, community ambulator without crutches (those who are able to walk outdoors, able to cope with stairs and public transport). Children who could not stand were excluded from the analysis. RESULTS
The patients were placed into three groups according to the extent of lengthening, and the results are
139
shown in Tables l-4. The ambulatory capability of the patients in each group was almost the same (Table 4). Group 1 (the proximal gastrocnemius recession group). The gastrocnemius was lengthened at the proximal intramuscular level. Mild, moderate and some severe deformities with flat foot gait, toe-heel gait and toe gait (DKE average - 14.7’. DKF - 3.2” were included. Group 2 (the distal gastrocnemius recession group). The gastrocnemius was lengthened at the proximal (intramuscular) and distal levels. Moderate and severe deformities with toe gait and toe cavus gait (DKE average -22.8”, DKF average - 13.8” were included. Group 3 (combined group). Achilles tendon lengthening was combined with the gastrocnemius aponeurotic lengthening. Severe deformities with toe gait and toe cavus gait (DKE average -32.3”. DKF average -22.5”) were also included. In 39 feet of group 1, DKE averaged - 14.7” preoperatively and 0.6” postoperatively, with an improvement of 15.3‘. DKF averaged - 3.2” preoperatively and 9.3” postoperatively, with an improvement of 12.5” (Table 1). Of the 17 feet with a toe-heel gait, 4 improved to a heel-toe gait and 13 to a flat foot gait. Of the 19 feet with a toe gait, 2 improved to a flat foot gait, 12 to a toe-heel gait, while 5 remained unchanged. 1 of 3 feet with toe cavus gait improved to a flat foot, and 2 to a toe gait (Table 2). In Kling’s evaluation, 19 were excellent, 13 good, and 7 remained poor with a recurrence of equinus deformity postoperatively (Table 3 ). The ambulatory grade averaged 5.0 preoperatively and 5.6 postoperatively with an improvement of 0.6 (Table 4). The correction was insufficient in severe deformities with a toe gait and a toe cavus gait, while an adequate correction was attained in mild deformities with a toe-heel gait. In 32 feet of group 2, DKE averaged -22.8” preoperatively and -4.3” postoperatively, with an improvement of 18.5’. DKF averaged - 13.8‘ preoperatively and 5.4” postoperatively, with an improvement of 19.2”. Of the 21 feet of a toe gait, 9 improved to a flat foot gait (Fig. 4), 7 to a toe-heel gait and 5 remained unchanged. Of the 11 feet with toe cavus gait, 1 improved to a flat foot gait (Fig. 5), 4 to a toe-heel gait and 6 to a toe gait. In Kling’s evaluation, 8 were excellent, 13 were good and 11 were poor. In the 11 feet with poor results, there was a recurrence of equinus deformity and thus heel cord lengthening was done as an additional operation with satisfactory results. The ambulatory grade averaged 4.9 preoperatively and 5.6 postoperatively, with the improvement being 0.7. In the 21 feet of group 3, DKE averaged -32.3” preoperatively, and 2.0” postoperatively, with an improvement of 34.3“. DKF averaged -22.5” preoperatively and 8.4’ postoperatively, with an improve-
Table 1. Pre- and postoperative
Group
1 2 3
status in the passive range of motion of DKE and DKF DKF
DKE Preop.
Postop.
Correction
Preop.
Postop.
Correction
- 14.7 -22.8 -32.3
-0.6 4.3 2.0
15.3 18.5 34.3
-3.2 - 13.8 -22.5
9.3 5.4 8.4
12.5 19.2 30.9
Table 2. Pre- and postoperative
Gait pattern
status in the gait pattern Group 1 Preop.
Toe cavus Toe Toe-heel Flat foot Heel-toe (normal) Calcaneus deformity
3 19 17
Group 2 Postop.
Preop.
results of Kling’s evaluation
Group 1
Group 2
Group 3
Excellent Good Poor
19 13 7
8 13 11
4 15 2
ment of 30.9”. Of the 18 feet of a toe cavus gait, 13 improved to a flat foot gait, 3 to a toe-heel gait, and 2 to a calcaneal gait with a weak plantar flexion. 3 feet of a toe gait improved to a flat foot gait. Clinically, 4 were excellent, 15 were good, and 2 remained poor. The ambulatory grade averaged 5.0 preoperatively and 5.7 postoperatively, with an improvement of 0.7 (Table 4). There were also 2 feet of a diplegic patient in which the push-off power had considerably deteriorated.
Table 4. Pre- and postoperative
18 3
11 11 10
3 16
The main characteristic of our approach was to correct equinus deformity with use of a lengthening of the gastrocnemius, peroneus longus, tibialis posterior and toe flexors, while preserving the activity of the soleus muscle. Although various procedures for spastic equinus deformity have been presented, attention has been mainly directed to the hyperactivity of the triceps surae.1-3*6 Achilles tendon lengthening has been commonly used. However, the postoperative weakening of push-off power can frequently present serious problems. With sufficient lengthening (overlengthening), push-off power weakens, stability in weightbearing decreases and calcaneal gait becomes dominant.6,‘5 This problem has been revealed in diplegic feet in which stability is poor bilaterally. The
status in ambulatory capability
Grade ambulatory capacity
Non-ambulator (wheelchair-bound) Non-functional ambulator (use of a walker) Household ambulator (crutches) Community ambulator (crutches) Household ambulator Community ambulator
Fig. 4-A
Postop.
DISCUSSION
Kling’s
Average grade
Preop.
2
Table 3. Postoperative
1. 2. 3. 4. 5. 6.
Postop.
11 21
7 12 16 4
Group 3
Group 1
Group 2
Group 3
Preop.
Postop.
Preop.
Postop.
Preop.
Postop.
0 3 0 3 10 12
0 1 0 2 5 20
1 2 1 0 7 10
0 0 0 3 2 16
2 0 0 0 9 8
0 1 0 1 0 17
5.0
5.6
4.9
5.6
5.0
5.7
9-year-old girl with spastic diplegia, ambulatory, group 2. (A) A crouched posture with equinus deformities and lumbar lordosis was evident. Preoperatively, the gait pattern was a toe gait. (B) The gastrocnemius was lengthened, at the proximal and distal levels. Achilles tendon lengthening was not combined. Postoperatively, the gait pattern improved to a flat foot gait. The crouched posture and lumbar lordosis decreased.
Combined lengthening of the plantar flexors of the ankle and foot for equinus gait in cerebral palsy
141
142
The Foot
Combined
lengthening
of the plantar
use of a short-leg brace is often needed to compensate postoperative weakness in plantar push-off power. Gastrocnemius aponeurotic lengthening is also an established procedure.’ The most important aspect of these procedures is that the activity in push-off power is not disturbed and adequate weightbearing while standing and walking is maintained.4,9x’5 However, in gastrocnemius aponeurotic lengthening, the high rate of recurrence can be a problem. Olney et al reported that 46% of the patients (105 of the 2 19) required repeat surgical treatment for recurrent equinus deformity.’ The original point of our procedure is that we considered the tibialis posterior and peroneus longus as one of the causes of equinus deformity and recurrence, and thus carried out a simultaneous intramuscular lengthening of these muscles. Anatomically, the peroneus longus is a plantar flexor with eversion. The hyperactivity of this muscle can therefore be defined as the cause of equinus deformity. The tibialis posterior has also been considered as a plantar flexor with inversion activity and a release operation has often been done to correct the varusequinus deformity. The combined hypertonic activity of the peroneus longus and tibialis posterior can, however, be a cause of equinus deformity and thus also be closely related to a recurrence. With use of intramuscular lengthening of these muscles, the hyperactivity of these midtarsal flexors could be adequately relieved. Hyperactivity of the toe flexors can also be a factor of recurrence. To facilitate dorsiflexors of the toes and ankle, relief of hypertonicity of the flexor hallucis longus and flexor digitorum longus is important. With the application of such combined lengthening, mild deformities were able to be corrected even in diplegic patients with a crouch posture, while decreasing the crouched posture (Fig. 4). In cases of moderate and severe deformity in group 2, a considerable correction of 18.5” in DKE, and 19.2” in DKF was attained, although recurrence was seen in 11 feet. Even in cases of severe deformity of 21 feet in group 3, the spasticity of the gastrocnemius, tibialis posterior and peroneus longus was adequately relieved, the extent of tendon could also be minimized, and therefore the push-off power of the soleus could be preserved. The problem of gastrocnemius aponeurotic lengthening and, intramuscular lengthening of the peroneus longus and tibialis posterior is that hyperactivity of the plantar flexors could not be completely overcome and recurrence was inevitable in cases of moderate
flexors of the ankle and foot for equinus
gait in cerebral
palsy
143
and severe deformity, even though a considerable correction was obtained. 18 feet ( 19.4%) treated with gastrocnemius aponeurotic lengthening (groups 1 and 2) without concomitant Achilles tendon lengthening had recurrences with a poor evaluation. 16 of these recurrent feet in groups 1 and 2 also could be corrected with satisfactory results using additional Achilles tendon lengthening. To prevent such recurrences, minimal concomitant Achilles tendon lengthening is thus indicated for these moderate or severe deformities. Using adequate but minimal concomitant Achilles tendon lengthening, postoperative stability could be preserved even in group 3, as shown by the improvement in ambulatory ability (Table 4). Regarding quantitative indications, we can therefore conclude that the gastrocnemius aponeurotic lengthening and intramuscular lengthening of the tibialis posterior and peroneus longus can be indicated for a correction of mild dynamic deformity in which DKE is more than - 10” with a toe-heel gait. For correction of moderate and severe deformities in which DKE is less than - 10” with a toe gait and toe cavus gait, the same procedure with concomitant Achilles tendon lengthening 1.O-2.0 cm long would be indicated. A serious problem that was occasionally observed was a reverse deformity due to a weakening of antigravitic push-off power after concomitant Achilles tendon lengthening. In 2 feet of a diplegic patient from group 3, the push-off power weakened and pes calcaneus gait occurred. The cause of this reverse deformity is considered to be the overlengthening of the Achilles tendon due to a loosening of the tendon suture after surgery. Minimal lengthening (0.7-2.0 cm) of the Achilles tendon with a precise technique (Fig. 1 ), firm fixation with an absorbable suture and careful immobilization by cast are thus needed to avoid such overlengthening. In summary, we found that the gastrocnemius aponeurotic lengthening and intramuscular lengthening of the peroneus longus and tibialis posterior either with or without concomitant Achilles tendon lengthening are beneficial for patients who have a dynamic equinus deformity secondary to cerebral palsy.
References I. Baker L D. Rational
approach to the surgical needs of the cerebral palsy patient. .i Bone Joint Surg 1956; 38A: 313-323. 2. Lee C L. Bleck E E. Surgical correction of equinus
Fig. 5-A lCyear-old boy with spastic diplegia. Non-ambulatory. (A) Equinovarus deformity with flexion of the hips, and knees was seen on bilateral feet. The gait pattern was a toe cavus gait. (B) The gastrocnemius was lengthened, at the proximal and distal level. Achilles tendon lengthening was not combined. For flexion deformities of the hips and knees, lengthening of the psoas and distal lengthening of the hamstrings were combined. Motor ability improved to a crutch gait, and the gait pattern improved to a flat foot gait.
144 The Foot
I. 8.
9.
10. 11.
12.
deformity in cerebral palsy. Dev Med Child Neurol 1980; 22: 2877292. Pierrot A H, Murphy 0 B. Heel cord advancement. Orthop Clin North Am 1974; 5: 117-126. Bleck E E. Orthopaedic management in cerebral palsy. Philadelphia: Lippincott, 1987: 240-245. Sharrard W J W, Bernstein S. Equinus deformity in cerebral palsy. J Bone Joint Surg 1972; 54B: 272-276. Segal L S, Thomas S E S, Mazur J M, Mauterer M. Calcaneal gait in spastic diplegia after heel cord lengthening. A study with gait analysis. J Pediatr Orthop 1989; 9: 697-701. Strayer L M. Recession of the gastrocnemius. J Bone Joint Surg 1950; 32A: 611-676. Javors J R, Klaaren H E. The vulpius procedure for correction of equinus deformity in cerebral palsy, J Pediatr Orthop 1987; 7: 191-193. Olney B W, William P F, Menelaus M B. Treatment of spastic equinus by aponeurosis lengthening. J Pediatr Orthop 1988; 8: 4222425. Matsuo T. Cerebral palsy and orthopaedics. Tokyo: Nankodo, 1991. Matsuo T, Tada S, Hajime T. Insufficiency of the hip adductor after anterior obturator neurectomy in 42 children with cerebral palsy. J Pediatr Orthop 1986; 6: 686-692. Matsuo T, Hara H, Tada S. Selective lengthening of the psoas and rectus femoris and preservation of the
iliacus for flexion deformity of the hip in cerebral palsy patients. J Pediatr Orthop 1987; 7: 690-698. 13. Kling T F, Kaufer H, Hensinger R N. Split posterior tibial-tendon transfers in children with cerebral spastic paralysis and equinovarus deformity. J Bone Joint Surg 1985; 67A: 186-194. 14. Hoffer M M. Functional ambulation in patients with myelomeningocele. J Bone Joint Surg 1973; 55A: 137-148. 15. Schwartz J R. Carr W. Bassett F H, Coonrad R W. Lessons learned in the treatment of equinus deformity in ambulatory spastic children. Orthop Trans 1977; 1: 84.
The authors Takasbi Matsuo MD Norihisa Kawada MD Osami Tondshige MD
Shinkoen Hospital for Handicapped Children 1592-l Kaminofu Shingu-cho Kasuya-gun Fukuoka 811-01 Japan Correspondence to Dr T. Matsuo.
4, 136-144
Combined lengthening of the plantar flexors of the ankle and foot for equinus gait in cerebral palsy T. Matsuo, N. Kawada, 0. Tomishige Department of Orthopaedic Surgery, Shinkoen Hospital for Handicapped Children, Fukuoka, Japan S UMMA R Y. 92 patients with equinus deformity treated by combined gastrocnemius aponeurotic lengthening, intramuscular lengthening of the peroneus longus and tabialis posterior, and sliding lengthening of the flexor hallucis longus and flexor digitorum longus either with or without concomitant Achilles tendon lengthening were reviewed an average of 4.2 years after operation. In 79.4% of the cases, the clinical results were satisfactory, including 41 excellent, 31 good and 20 poor outcomes. There were improvements in the range of motion, gait pattern and ambulatory capability. 18 feet with severe deformities had a poor result with a recurrence of equinus and equinovarus deformities. 2 of 21 feet with concomitant Achilles tendon lengthening had a poor result with a calcaneal gait.
Equinus is the most common deformity in patients with cerebral palsy and stable weightbearing is impaired as a result of a decrease in the support at the base of the foot. Hyperactivity of the plantar flexors is generally the major cause of this deformity. To correct this deformity, various procedures have been describedIm Achilles tendon lengthening has been widely used,2,4,5 but the postoperative results still leave much to be desired. When the triceps surae is lengthened too much, the push-off power weakens and stable weightbearing is no longer feasible.6 The use of a brace is often necessary to overcome the weakness in the plantar flexors. Conversely, when the lengthening is insufficient there will be a recurrence. Bleck has previously discussed which operation offers the best compromise between relieving the contracture and preserving the strength.4 Gastrocnemius aponeurotic lengthening was designed to lengthen the gastrocnemius and to spare the soleus muscle and has been reported by Baker & Hill’ and Strayer.7 The objective of this procedure is to relieve spasticity and to preserve strength. The results have been satisfactory with respect to the preservation of stability, 6,8*9however, the recurrence rate has remained high.’ In an attempt to overcome these problems, we directed our attention to the hyperactivity of other plantar flexors, such as the peroneus longus and tibialis posterior, as a cause of the deformity, and designed a combined release operation which involves the intramuscular lengthening of these muscles. lo The details of this operation are herein described, and the muscular factors leading to equinus deformity, as well as the surgical techniques used
to control the hypertonicity also discussed.
of these muscles, are
MATERIALS AND METHODS Patients Between May 1983 and December 1989, 143 feet with equinus deformity in 102 patients were treated with combined lengthening, including fractional lengthening of the tibialis posterior and peroneus longus, sliding lengthening of the flexor hallucis longus and digitorum longus, and aponeurotic lengthening of the gastrocnemius. Of these, 92 feet of 63 patients could be followed and their related activities were monitored. 5 patients (5 feet) were diagnosed as cases of spastic monoplegia, 14 (14 feet) as cases of spastic hemiplegia, 43 (72 feet) as cases of spastic diplegia, and 1 (1 foot) as a case of spastic triplegia. 2 patients (3 feet) with tension athetosis were excluded from the analysis. 53 patients were ambulatory, 2 were ambulatory with crutches, 5 were ambulatory with the use of a walker and 3 were able to stand with selfsupport. Children at the non-sitting level, propped sitting level, and sitting level were excluded from the evaluation in this study. The ages at the time of surgery ranged from 3 to 19 years, with an average of 9 years and 1 month. All patients were followed for an average of 4.2 years, range 2-8.3 years. The combined surgery in the lower extremities included a lengthening of the psoas as well as a proximal lengthening of the hamstrings in 33 hips and a distal lengthening of the hamstrings in 4 knees.l’*” All treatment and follow-up procedures were carried 136
Combined lengthening of the plantar flexors of the ankle and foot for equinus gait in cerebral palsy
out at the Shinkoen Hospital Children, Fukuoko, Japan.
for
Handicapped
Method
A longitudinal incision is made over the medial side of the Achilles tendon. The tendon of the flexor hallucis longus and flexor digitorum longus are lengthened, using sliding technique. At the distal third of the medial aspect of the calf, the tibialis posterior is identified and the musculotendinous junction of the tibialis posterior is lengthened using fractional lengthening (Fig. 1). At the one-half level of the lateral aspect of the calf, the musculotendinous junction of the peroneus longus is visualized and then lengthened (Fig. 2). Care must be taken not to lengthen the peroneus brevis tendon which is located just anterior to the peroneus longus. Over the middle of the calf, the aponeurotic tendon of the gastrocnemius and soleus is divided just distal to the gastrocnemius muscle. In the case of a moderate to severe deformity, the aponeurosis at the 2-4 cm distal level is also sectioned. In the case of a severe deformity, the Achilles tendon is carefully lengthened to the desired length using a sliding technique (Fig. 3). A cast is applied from the groin to the toes, with the knee in moderate flexion and the foot in a slight plantarflexion for 2-3 weeks in cases of aponeurotic lengthening of the gastrocnemius. In cases with
137
Achilles tendon lengthening, fixation is extended to 6 weeks. An orthosis is used for 2-3 months for a foot with Achilles tendon lengthening. A night splint is not necessary. Evaluation
To determine the extent of the lengthening and to evaluate the results of this surgical repair, the passive range of motion of the ankle is measured. Gait pattern, clinical assessment according to Kling’s evaluation and the ambulatory capability is also evaluated.13 Passive dorsiflexion
With the knee extended and the foot in a neutral position, passive dorsiflexion of the ankle (dorsiflexion with knee extension, DKE) is measured. With the knee flexed, passive dorsiflexion of the ankle (dorsiflexion with knee flexion, DKF) is measured. The feet in which DKE is more than -10” was categorized as mild deformity; those in which DKE is between - IO” and -25”, as moderate; and those in which DKE is less than -25”, as severe. Gait pattern
To assess dynamic deformity during gait, the gait pattern was used. The categories of the gait pattern include a heel-toe gait, a flat foot gait, a toe-heel
Flexor digitorum
I
posterior
longus
\\
tibia1 vessels
I
Fractional lengthening
-a -.
^L, ,,,,d
I’\’ ,l>
’
\
Tibialis posterior
Fig. l-Intramuscular lengthening of the tibialis posterior. A longitudinal incision is made on the distal third of the medial aspect of the calf. Retracting the soleus and the tibia1 vessels and nerve posteriorly and the flexor digitdrum longus medially, the musculotendinous junction of the tibialis posterior is identified and then lengthened using the fractional technique.
,Peroneus
’ Fractional
longus
lengthening \
Peroneus
brevis
Fig. 2-Intramuscular lengthening of the peroneus longus. On the one-half of the lateral aspect of the calf, the musculotendinous junction of the peroneus longus is lengthened using the fractional technique. The peroneus brevis located just anterior to the peroneus longus is carefully protected since it is an important dorsiflexor.
Gastrocnemius
Sliding lengthenin
Fig. 3-Heel cord lengthening and gastrocnemius aponeurotic lengthening. (A) Sliding lengthening of the Achilles tendon. After the Achilles tendon is exposed, two plastic tubes are inserted under the tendon. An absorbable suture is inserted. One half of the Achilles tendon is cut above the posterolateral aspect and one half is cut below the medial aspect. Passive dorsiflexion of the ankle results in sliding lengthening. Fixation with the inserted suture is important to prevent any postoperative overlengthening. (B) Aponeurotic lengthening at the proximal level. Tendons of the gastrocnemius and soleus are incised at the level just distal to the gastrocnemius muscles. (C) Aponeurotic lengthening at the distal level. Tendons of the gastrocnemius and soleus are lengthened using aponeurotic lengthening at the level 2-3 cm distal to the gastrocnemius muscles.
Combined lengthening of the plantar flexors of the ankle and foot for equinus gait in cerebral palsy
gait, a toe gait, a toe cavus gait and a calcaneal gait. In the heel-toe gait, there is a gait with heel contact and toe-off pattern. In the flat foot gait, plantigrade foot is accomplished but no heel contact and toe-off pattern is seen. In the toe-heel gait, weightbearing is made on the forefoot, but there is only temporary heel contact. In the toe gait, weightbearing is made only on the forepart of the foot. In the toe cavus gait, the gait includes a toe gait with a marked cavus deformity. In the calcaneal gait, a gait with calcaneus deformity is present and the forward leaning of the tibia in the stance phase is over 15”. Clinical evaluation (Kling’s)
The rating system of Kling et ali3 was used to categorize the clinical results. Patients who walked with a plantigrade foot, without any fixed or postural deformity in regular shoes and had normal callosities, had excellent results. They did not need an orthosis postoperatively and were pleased with the results. Children who walked with less than 5” of varus, valgus or equinus posture of the foot, wore regular shoes with no abnormal shoe wear, had normal callosities, and who were satisfied with the outcome, had good results. Those whose feet had a recurrent equinus deformity or were overcorrected into a calcaneus deformity had poor results. Ambulatory capability
In order to compare pre- and postoperative stability, the ambulatory capability of each patient without a brace was evaluated, according to the modified Hoffer’s evaluation.14 A numerical grade was assigned to each class: grade 1, non-ambulator (wheelchairbound patients, those who are only able to stand when moving from bed to chair); grade 2, nonfunctional ambulator (wheelchair-bound patients, those who are able to walk with the use of walker on a level floor); grade 3. household ambulator with crutches (those who are able to walk short distances within the home); grade 4, community ambulator with crutches (those who are able to walk outdoors with the use of crutches; wheelchair only needed for long distances); grade 5, household ambulator without crutches (those who are able to walk within the home without the use of crutches and braces; crutches only needed for long distances); and grade 6, community ambulator without crutches (those who are able to walk outdoors, able to cope with stairs and public transport). Children who could not stand were excluded from the analysis. RESULTS
The patients were placed into three groups according to the extent of lengthening, and the results are
139
shown in Tables l-4. The ambulatory capability of the patients in each group was almost the same (Table 4). Group 1 (the proximal gastrocnemius recession group). The gastrocnemius was lengthened at the proximal intramuscular level. Mild, moderate and some severe deformities with flat foot gait, toe-heel gait and toe gait (DKE average - 14.7’. DKF - 3.2” were included. Group 2 (the distal gastrocnemius recession group). The gastrocnemius was lengthened at the proximal (intramuscular) and distal levels. Moderate and severe deformities with toe gait and toe cavus gait (DKE average -22.8”, DKF average - 13.8” were included. Group 3 (combined group). Achilles tendon lengthening was combined with the gastrocnemius aponeurotic lengthening. Severe deformities with toe gait and toe cavus gait (DKE average -32.3”. DKF average -22.5”) were also included. In 39 feet of group 1, DKE averaged - 14.7” preoperatively and 0.6” postoperatively, with an improvement of 15.3‘. DKF averaged - 3.2” preoperatively and 9.3” postoperatively, with an improvement of 12.5” (Table 1). Of the 17 feet with a toe-heel gait, 4 improved to a heel-toe gait and 13 to a flat foot gait. Of the 19 feet with a toe gait, 2 improved to a flat foot gait, 12 to a toe-heel gait, while 5 remained unchanged. 1 of 3 feet with toe cavus gait improved to a flat foot, and 2 to a toe gait (Table 2). In Kling’s evaluation, 19 were excellent, 13 good, and 7 remained poor with a recurrence of equinus deformity postoperatively (Table 3 ). The ambulatory grade averaged 5.0 preoperatively and 5.6 postoperatively with an improvement of 0.6 (Table 4). The correction was insufficient in severe deformities with a toe gait and a toe cavus gait, while an adequate correction was attained in mild deformities with a toe-heel gait. In 32 feet of group 2, DKE averaged -22.8” preoperatively and -4.3” postoperatively, with an improvement of 18.5’. DKF averaged - 13.8‘ preoperatively and 5.4” postoperatively, with an improvement of 19.2”. Of the 21 feet of a toe gait, 9 improved to a flat foot gait (Fig. 4), 7 to a toe-heel gait and 5 remained unchanged. Of the 11 feet with toe cavus gait, 1 improved to a flat foot gait (Fig. 5), 4 to a toe-heel gait and 6 to a toe gait. In Kling’s evaluation, 8 were excellent, 13 were good and 11 were poor. In the 11 feet with poor results, there was a recurrence of equinus deformity and thus heel cord lengthening was done as an additional operation with satisfactory results. The ambulatory grade averaged 4.9 preoperatively and 5.6 postoperatively, with the improvement being 0.7. In the 21 feet of group 3, DKE averaged -32.3” preoperatively, and 2.0” postoperatively, with an improvement of 34.3“. DKF averaged -22.5” preoperatively and 8.4’ postoperatively, with an improve-
Table 1. Pre- and postoperative
Group
1 2 3
status in the passive range of motion of DKE and DKF DKF
DKE Preop.
Postop.
Correction
Preop.
Postop.
Correction
- 14.7 -22.8 -32.3
-0.6 4.3 2.0
15.3 18.5 34.3
-3.2 - 13.8 -22.5
9.3 5.4 8.4
12.5 19.2 30.9
Table 2. Pre- and postoperative
Gait pattern
status in the gait pattern Group 1 Preop.
Toe cavus Toe Toe-heel Flat foot Heel-toe (normal) Calcaneus deformity
3 19 17
Group 2 Postop.
Preop.
results of Kling’s evaluation
Group 1
Group 2
Group 3
Excellent Good Poor
19 13 7
8 13 11
4 15 2
ment of 30.9”. Of the 18 feet of a toe cavus gait, 13 improved to a flat foot gait, 3 to a toe-heel gait, and 2 to a calcaneal gait with a weak plantar flexion. 3 feet of a toe gait improved to a flat foot gait. Clinically, 4 were excellent, 15 were good, and 2 remained poor. The ambulatory grade averaged 5.0 preoperatively and 5.7 postoperatively, with an improvement of 0.7 (Table 4). There were also 2 feet of a diplegic patient in which the push-off power had considerably deteriorated.
Table 4. Pre- and postoperative
18 3
11 11 10
3 16
The main characteristic of our approach was to correct equinus deformity with use of a lengthening of the gastrocnemius, peroneus longus, tibialis posterior and toe flexors, while preserving the activity of the soleus muscle. Although various procedures for spastic equinus deformity have been presented, attention has been mainly directed to the hyperactivity of the triceps surae.1-3*6 Achilles tendon lengthening has been commonly used. However, the postoperative weakening of push-off power can frequently present serious problems. With sufficient lengthening (overlengthening), push-off power weakens, stability in weightbearing decreases and calcaneal gait becomes dominant.6,‘5 This problem has been revealed in diplegic feet in which stability is poor bilaterally. The
status in ambulatory capability
Grade ambulatory capacity
Non-ambulator (wheelchair-bound) Non-functional ambulator (use of a walker) Household ambulator (crutches) Community ambulator (crutches) Household ambulator Community ambulator
Fig. 4-A
Postop.
DISCUSSION
Kling’s
Average grade
Preop.
2
Table 3. Postoperative
1. 2. 3. 4. 5. 6.
Postop.
11 21
7 12 16 4
Group 3
Group 1
Group 2
Group 3
Preop.
Postop.
Preop.
Postop.
Preop.
Postop.
0 3 0 3 10 12
0 1 0 2 5 20
1 2 1 0 7 10
0 0 0 3 2 16
2 0 0 0 9 8
0 1 0 1 0 17
5.0
5.6
4.9
5.6
5.0
5.7
9-year-old girl with spastic diplegia, ambulatory, group 2. (A) A crouched posture with equinus deformities and lumbar lordosis was evident. Preoperatively, the gait pattern was a toe gait. (B) The gastrocnemius was lengthened, at the proximal and distal levels. Achilles tendon lengthening was not combined. Postoperatively, the gait pattern improved to a flat foot gait. The crouched posture and lumbar lordosis decreased.
Combined lengthening of the plantar flexors of the ankle and foot for equinus gait in cerebral palsy
141
142
The Foot
Combined
lengthening
of the plantar
use of a short-leg brace is often needed to compensate postoperative weakness in plantar push-off power. Gastrocnemius aponeurotic lengthening is also an established procedure.’ The most important aspect of these procedures is that the activity in push-off power is not disturbed and adequate weightbearing while standing and walking is maintained.4,9x’5 However, in gastrocnemius aponeurotic lengthening, the high rate of recurrence can be a problem. Olney et al reported that 46% of the patients (105 of the 2 19) required repeat surgical treatment for recurrent equinus deformity.’ The original point of our procedure is that we considered the tibialis posterior and peroneus longus as one of the causes of equinus deformity and recurrence, and thus carried out a simultaneous intramuscular lengthening of these muscles. Anatomically, the peroneus longus is a plantar flexor with eversion. The hyperactivity of this muscle can therefore be defined as the cause of equinus deformity. The tibialis posterior has also been considered as a plantar flexor with inversion activity and a release operation has often been done to correct the varusequinus deformity. The combined hypertonic activity of the peroneus longus and tibialis posterior can, however, be a cause of equinus deformity and thus also be closely related to a recurrence. With use of intramuscular lengthening of these muscles, the hyperactivity of these midtarsal flexors could be adequately relieved. Hyperactivity of the toe flexors can also be a factor of recurrence. To facilitate dorsiflexors of the toes and ankle, relief of hypertonicity of the flexor hallucis longus and flexor digitorum longus is important. With the application of such combined lengthening, mild deformities were able to be corrected even in diplegic patients with a crouch posture, while decreasing the crouched posture (Fig. 4). In cases of moderate and severe deformity in group 2, a considerable correction of 18.5” in DKE, and 19.2” in DKF was attained, although recurrence was seen in 11 feet. Even in cases of severe deformity of 21 feet in group 3, the spasticity of the gastrocnemius, tibialis posterior and peroneus longus was adequately relieved, the extent of tendon could also be minimized, and therefore the push-off power of the soleus could be preserved. The problem of gastrocnemius aponeurotic lengthening and, intramuscular lengthening of the peroneus longus and tibialis posterior is that hyperactivity of the plantar flexors could not be completely overcome and recurrence was inevitable in cases of moderate
flexors of the ankle and foot for equinus
gait in cerebral
palsy
143
and severe deformity, even though a considerable correction was obtained. 18 feet ( 19.4%) treated with gastrocnemius aponeurotic lengthening (groups 1 and 2) without concomitant Achilles tendon lengthening had recurrences with a poor evaluation. 16 of these recurrent feet in groups 1 and 2 also could be corrected with satisfactory results using additional Achilles tendon lengthening. To prevent such recurrences, minimal concomitant Achilles tendon lengthening is thus indicated for these moderate or severe deformities. Using adequate but minimal concomitant Achilles tendon lengthening, postoperative stability could be preserved even in group 3, as shown by the improvement in ambulatory ability (Table 4). Regarding quantitative indications, we can therefore conclude that the gastrocnemius aponeurotic lengthening and intramuscular lengthening of the tibialis posterior and peroneus longus can be indicated for a correction of mild dynamic deformity in which DKE is more than - 10” with a toe-heel gait. For correction of moderate and severe deformities in which DKE is less than - 10” with a toe gait and toe cavus gait, the same procedure with concomitant Achilles tendon lengthening 1.O-2.0 cm long would be indicated. A serious problem that was occasionally observed was a reverse deformity due to a weakening of antigravitic push-off power after concomitant Achilles tendon lengthening. In 2 feet of a diplegic patient from group 3, the push-off power weakened and pes calcaneus gait occurred. The cause of this reverse deformity is considered to be the overlengthening of the Achilles tendon due to a loosening of the tendon suture after surgery. Minimal lengthening (0.7-2.0 cm) of the Achilles tendon with a precise technique (Fig. 1 ), firm fixation with an absorbable suture and careful immobilization by cast are thus needed to avoid such overlengthening. In summary, we found that the gastrocnemius aponeurotic lengthening and intramuscular lengthening of the peroneus longus and tibialis posterior either with or without concomitant Achilles tendon lengthening are beneficial for patients who have a dynamic equinus deformity secondary to cerebral palsy.
References I. Baker L D. Rational
approach to the surgical needs of the cerebral palsy patient. .i Bone Joint Surg 1956; 38A: 313-323. 2. Lee C L. Bleck E E. Surgical correction of equinus
Fig. 5-A lCyear-old boy with spastic diplegia. Non-ambulatory. (A) Equinovarus deformity with flexion of the hips, and knees was seen on bilateral feet. The gait pattern was a toe cavus gait. (B) The gastrocnemius was lengthened, at the proximal and distal level. Achilles tendon lengthening was not combined. For flexion deformities of the hips and knees, lengthening of the psoas and distal lengthening of the hamstrings were combined. Motor ability improved to a crutch gait, and the gait pattern improved to a flat foot gait.
144 The Foot
I. 8.
9.
10. 11.
12.
deformity in cerebral palsy. Dev Med Child Neurol 1980; 22: 2877292. Pierrot A H, Murphy 0 B. Heel cord advancement. Orthop Clin North Am 1974; 5: 117-126. Bleck E E. Orthopaedic management in cerebral palsy. Philadelphia: Lippincott, 1987: 240-245. Sharrard W J W, Bernstein S. Equinus deformity in cerebral palsy. J Bone Joint Surg 1972; 54B: 272-276. Segal L S, Thomas S E S, Mazur J M, Mauterer M. Calcaneal gait in spastic diplegia after heel cord lengthening. A study with gait analysis. J Pediatr Orthop 1989; 9: 697-701. Strayer L M. Recession of the gastrocnemius. J Bone Joint Surg 1950; 32A: 611-676. Javors J R, Klaaren H E. The vulpius procedure for correction of equinus deformity in cerebral palsy, J Pediatr Orthop 1987; 7: 191-193. Olney B W, William P F, Menelaus M B. Treatment of spastic equinus by aponeurosis lengthening. J Pediatr Orthop 1988; 8: 4222425. Matsuo T. Cerebral palsy and orthopaedics. Tokyo: Nankodo, 1991. Matsuo T, Tada S, Hajime T. Insufficiency of the hip adductor after anterior obturator neurectomy in 42 children with cerebral palsy. J Pediatr Orthop 1986; 6: 686-692. Matsuo T, Hara H, Tada S. Selective lengthening of the psoas and rectus femoris and preservation of the
iliacus for flexion deformity of the hip in cerebral palsy patients. J Pediatr Orthop 1987; 7: 690-698. 13. Kling T F, Kaufer H, Hensinger R N. Split posterior tibial-tendon transfers in children with cerebral spastic paralysis and equinovarus deformity. J Bone Joint Surg 1985; 67A: 186-194. 14. Hoffer M M. Functional ambulation in patients with myelomeningocele. J Bone Joint Surg 1973; 55A: 137-148. 15. Schwartz J R. Carr W. Bassett F H, Coonrad R W. Lessons learned in the treatment of equinus deformity in ambulatory spastic children. Orthop Trans 1977; 1: 84.
The authors Takasbi Matsuo MD Norihisa Kawada MD Osami Tondshige MD
Shinkoen Hospital for Handicapped Children 1592-l Kaminofu Shingu-cho Kasuya-gun Fukuoka 811-01 Japan Correspondence to Dr T. Matsuo.