Given the unique challenges of treating pediatric equinus, these authors offer pertinent diagnostic insights, discuss potential signs of compensation for equinus and review key treatment considerations.
By definition, equinus is the limitation of normal ankle joint dorsiflexion with the subtalar joint maintained in its neutral position.1 In the pediatric patient, it is important to recognize and diagnose equinus. When evaluating the pediatric foot and ankle for normal range of motion, the expected value at birth is 75 degrees of dorsiflexion with no functional limitations. As the child ages, this value will decrease to approximately 20 to 25 degrees of dorsiflexion at age three, approximately 10 to 15 degrees of dorsiflexion at age 10 to 15 and approximately 10 degrees at age 15, which is akin to that of an adult.2,3
This expected pediatric range of motion requires a specific evaluation technique different from that of Root’s method, which was extrapolated by Gatt and colleagues.4 These pediatric-focused methods of measurement require that the patient be in a supine position with the hip either flexed or extended, and the foot in mild supination before achieving ankle dorsiflexion. One should not allow the subtalar joint to be pronated, which can cause the midtarsal joint to become unlocked, creating excessive forefoot dorsiflexion.
When it comes to children, it is especially important to truly isolate the rearfoot on the ankle joint as a child’s forefoot tends to be more flexible than that of an adult.
A good method of performing this evaluation involves placing a tractograph on the lateral aspect of the foot and lower one-third of the leg. Certain tractographs have a compass feature in the central arm, which clinicians can align with the lateral malleolus. This allows one to easily and swiftly obtain a specific numerical measurement while the child remains cooperative.
Ganley discusses two key things in the pediatric exam: swiftness and the use of an assistant to record any abnormal measurements.5 My personal interaction working side-by-side with Bresnahan also supports this concept.6 Additionally, when obtaining these values, one may find that the child will push against your your hand with his or her foot. Clinicians can easily handle this by sweeping the sole of the foot with their hand, creating a withdrawal reflex. As a result, one can manipulate the foot while distracting the patient and obtain an accurate measurement.
Evaluation of the source of the equinus is necessary to properly address the deforming force. Classically, utilizing the Silfverskiold test allows you to isolate normal range of motion versus gastroc equinus versus gastro-soleus equinus. In a standard test, there is normal dorsiflexion with the knee extended and flexed.7 With pure gastrocnemius equinus, ankle dorsiflexion is less than zero degrees with the knee extended but with knee flexion, there is normal dorsiflexion. In the findings of pure gastrocnemius-soleus equinus, ankle dorsiflexion is less than zero degrees with the knee both bent and extended.
Differentiating Various Types Of Equinus In The Pediatric Patient
Some common types of equinus include: congenital gastrocnemius equinus, congenital soleus equinus (rare), congenital gastrocnemius-soleus equinus, bone block equinus and spastic equinus.
Congenital gastrocnemius equinus is the most common form marked by limited dorsiflexion with the subtalar joint in neutral with the knee fully extended. Congenital gastrocnemius-soleus equinus exhibits limited dorsiflexion with the knee flexed and a spongy feel at the end range of motion. This is in comparison to bone block equinus, which has a distinct hard stop due to the abutment of the talus on the tibia. One can confirm this with the use of weightbearing lateral stress films.
Spastic equinus is common in patients with cerebral palsy and hyperkinesia. With spastic equinus, clinicians will note limited dorsiflexion in both the extended knee and flexed knee along with an increased Achilles reflex and ankle clonus. One can evaluate clonus in the ankle joint by slowly dorsiflexing the foot, allowing it to relax and then forcibly dorsiflexing the foot. Due to spasticity, you will be able to see clonus with the foot moving after range of motion is complete.
Another form of pediatric equinus includes compensatory equinus, which is common in cases of flexible pes plano valgus in which excessive subtalar pronation results in the shortening of the gastrocnemius-soleal complex. Athletic equinus is an anatomy-driven increase in fibril volume, which decreases elasticity in the athlete. Elaborating on this concept, DeHeer noted that athletic equinus is an extremely common finding in those active in sports in general.8 Lastly, there is transitional equinus, which is associated with rapid bone growth without equal lengthening in the respective muscle components.3
What The Podiatrist Should Know About Compensation For Equinus
Upon further clinical weightbearing and gait examination, the clinician would note several things when it comes to potential compensation for equinus. First, when the subtalar joint pronates, there is abduction of the foot to reduce the need for ankle dorsiflexion. There is often early heel-off due to the gastrocnemius component along with knee flexion during the gait cycle.
There are different levels of compensation one may see with equinus. With a fully compensated foot, there is maximal pronation with calcaneal eversion and unrestricted subtalar joint range of motion. One will also note in these cases minimal rearfoot varus, which allows the midtarsal joint to unlock and the forefoot to dorsiflex. This can lead to a rocker-bottom foot type at its most extreme.
With partially compensated equinus, there is a low degree of subtalar joint pronation and a high degree of rearfoot varus not allowing the midtarsal joint to unlock. To accommodate, there is abduction, early heel off, genu recurvatum and knee flexion during gait. In an uncompensated state, there is extreme muscle shortening and no heel contact, often referred to as toe walking. As DeCaro has pointed out and the literature supports, the commonly known term “idiopathic toe walking” is not correct in that the reason for the toe walking has a multifactorial cause, and one can easily diagnose the etiology through proper evaluation.9,10
Identifying Multiple Etiologies Of Equinus In Children
There may be neurological causes for equinus in patients with cerebral palsy or Duchenne muscular dystrophy. In these cases, the equinus deformity limits clearance in swing phase to properly dorsiflex the foot, leading to a delayed stance phase, no heel contact and mild premature heel-off. Having the child do a deep knee bend or squat can be a very useful test if you suspect muscular dystrophy. If the child can squat with both feet planted squarely, his or her Achilles tendons are not too tight. If the child is able to get up from the squat to standing without help, it indicates strong quadriceps, which is the muscle group most quickly affected in the case of muscular dystrophy.11
One should treat toe walking as a disease of exclusion and attempt to rule out everything that could cause it. Common differential diagnoses include cerebral palsy, muscular dystrophy, hereditary equinus, talipes equinovarus and cavus foot deformity. A multicenter Swedish study found that diagnosing equinus early is key.12 The study showed that when toe walking exceeds five years, there is likely a neurological cause that needs evaluation and treatment. Prolonged toe walking can occur in children with cognitive delay. Toe walking can be a normal finding in children up to age five and affects boys to girls in a 3:1 ratio.
After ruling out neurological causes, it may be prudent to seek the evaluation of a pediatric occupational therapist as well as a pediatric ophthalmologist. Vision deficits can at times be one of the reasons for the child elevating onto his or her toes to walk. In the office, one can easily evaluate this by changing the field of vision of the child during the gait phase. Clinicians can do this by having the child walk regularly with his or her eyes facing forward, and then stressing the exam by either having the child look up and continue to walk, or having the child look down and see if his or her toe walking is affected.13
Understanding The Sequelae Of Equinus In Children
Multiple pathomechanical issues can occur secondary to equinus. In the pediatric patient, common issues, primarily Sever’s disease, are due to the excessive pull on the calcaneal apophysis in the growing child.3 Levangie and Norkin note that equinus limits advancement of the tibia relative to the foot during the midstance phase of gait.14 This can lead to a cavus foot type as well as obesity due to recurrent pes plano valgus as well as the lack of activity due to limitations caused by equinus.15 The limitations in activity can be due to discomfort, abnormal gait and functional limitation.
The most common repercussion of equinus that we see in our office is calcaneal apophysitis/Sever’s disease. There is extreme pressure on children to excel at sports among our office patient population and this leads to children specializing in sports at a younger age. It is common to find an increase in overuse injuries with Sever’s disease being a primary one, which is especially common at the beginning of sports seasons. This overuse syndrome is thought to be caused by repetitive microtrauma due to increased traction of the calcaneal-Achilles apophysis.
The child with Sever’s disease presents with a complaint of pain near the lower posterior heel, close to the Achilles attachment into the secondary growth plate of the calcaneus. The patient usually notes pain after performing the sport with an increase in severity of the pain during the activity. Evaluation of foot function, equinus and plain film weightbearing X-rays to assess the calcaneal apophysis and foot position are mandatory.
Due to the presence of growth plates at different ages, it is always necessary to perform bilateral foot X-rays when evaluating this issue. Utilization of the common dorsoplantar view, medial oblique view, lateral view, calcaneal axial and hindfoot alignment views are important. These views can confirm your physical findings and permit more comprehensive evaluation of calcaneal pathology.8
Flexible flatfoot in a child up to the age of seven can be a contributing factor for equinus. Valmassy’s rule of sevens discusses the appropriate progression up to the age of seven for hindfoot alignment.1 It is at the age of seven that the child’s foot typically takes on the adult form. When dealing with flexible flatfoot, there may be findings of a low longitudinal arch, everted calcaneus and abduction of the forefoot in stance as we previously discussed. In order to properly compensate for this, the patient may experience gastro-soleus shortening over a period of time.
Key Considerations In Treatment Of Pediatric Equinus
The key to equinus treatment is early identification. Early intervention with a stretching program can be beneficial and utilization of a physical therapist who is familiar with the pediatric patient is essential. Common stretches including the runner’s stretch, the soleus stretch, the band stretch as well as foam rolling can be beneficial and will allow the pediatric patient to be involved in his or her care (see top left photo on page 42). The use of stretching splints, especially those that address the gastroc component and allow the patient to keep the knee in a stabilized position, is crucial. In severe cases, a splint that has a negative footplate can be helpful, especially for neurological patients, to slowly stretch the foot and ankle complex.
Stretching is a key starting point for the pediatric patient, especially those involved in athletics. Grady, Saxena and colleagues found that stretching for five minutes a day for a six-month window increased dorsiflexion by an average of 2.7 degrees.16 In our practice, we have found that most child athletes do not properly stretch before these activities and this can lead to overuse injuries.
Utilization of casting can be beneficial in the most severe of cases. I would only advise casting when the child is at risk to him- or herself due to the deformity or if one anticipates the end result to involve a severe change in foot position.17
Orthotic management is essential. The gold standard for orthotic management is a custom-molded orthotic but financial restrictions may prevent use of this option. Alternatively, utilizing prefabricated orthotics to place the subtalar joint in a neutral position while maintaining heel alignment with a lateral clip/flange and maintaining the abduction at the midfoot can be effective. Often, if there is a finding of equinus severe enough that there is toe walking involved and the patient is not responding to orthotics, carbon fiber foot plates can be beneficial to force the heel down as the child walks. Other options include utilization of a forefoot varus post to limit pronation of the first ray and decrease the amount of compensatory equinus in gait.18
Other modalities in our practice that have been beneficial for the treatment of equinus include the Graston technique, kinesiology taping, shoe modifications and, most importantly, the involvement of the parents in the treatment plan. There are also multiple studies that have shown that botulinum injections are beneficial for spasticity although long-term results are limited.19,20
One should not take surgical intervention for pediatric equinus lightly. In situations of spastic equinus in which the neurological component is not responding to conservative care, the surgeon has the option to attempt advancement of the Achilles insertion anteriorly to decrease the lever arm of the Achilles.8 In regard to non-neurological surgery, it is in my opinion to limit the cutting of the Achilles tendon in the pediatric patients so as not to lose levels of strength. While percutaneous Achilles tenotomy is the mainstay in clubfoot treatment, it is imperative to maintain the strength of the Achilles tendon once the patient is in adolescence.21
One method to limit the loss of strength and power is the use of the Baumann gastrocnemius recession involving the open release of the gastro-soleal sheath. This allows the surgeon to improve dorsiflexion without weakening the Achilles tendon.2 An endoscopic approach is also useful to allow for a minimally invasive technique if the surgeon is comfortable with this option.
Although previous studies have been primarily focused on reserving an endoscopic approach only for pediatric patients with known neurologic deficits, Grady and colleagues have demonstrated this minimally invasive approach can be beneficial in pediatric and adolescent patients whose gastrocnemius equinus could not be treated non-operatively and who are without neurologic limitations.16 We have found in our practice that the utilization of these techniques as a component to treating equinus can be extremely beneficial and allows for a quicker return to activity for the pediatric patient.
Early identification of equinus is key to successful treatment. One should identify the cause of equinus with a teamwork approach, especially involving physical therapy, occupational therapists and neurologists if necessary. It is important to incorporate the patient’s family, educating as to the reason for the child’s complaint and getting everyone involved in the treatment plan.
In the current youth sports environment, it is necessary to assess whether the child is stretching and conditioning properly for the sport in which he or she participates. It is also important to look out for risk factors for overuse syndromes. One must manage expectations properly to prevent injury to the pediatric patient. It is always important as the child continues to grow to monitor periodically for improvement as well as maintain appropriate fit for any devices that you may be prescribing. As the senior author always says when treating pediatric patients, “It is a joy to treat this population because this population has a particular way of getting better when the appropriate treatment is rendered.”
Dr. Pagano is in private practice in Plymouth Meeting, Pa. He is the course director of Pediatric Foot and Ankle Orthopedics at Temple University School of Podiatric Medicine. Dr. Pagano is the Vice President of the American College of Foot and Ankle Pediatrics, and the on-air expert for Spenco Medical on QVC.
Dr. Varghese is an Associate of the American College of Foot and Ankle Surgeons, board-qualified in foot and ankle surgery and is an attending physician for the Einstein Medical Center Podiatric Residency Program. She is in private practice in Plymouth Meeting, Pa.
Dr. Hoto is board-qualified in foot and ankle surgery. He is a Diplomate of the American Board of Wound Management, in private practice in Plymouth Meeting, Pa. and Teaching Faculty at Einstein Medical Center Montgomery Podiatric Surgical Residency.
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