Cerebral palsy (CP) is a descriptive term for a group of disorders affecting motor function as a result of nonprogressive disturbances that occur in the developing brain. It is the leading cause of childhood disability worldwide, affecting nearly 3 in every 1,000 live births. Individuals affected by CP have varying degrees of physical disability, which may be accompanied by seizure disorders, as well as cognitive, speech, behavioral, and/or feeding impairment. The management of children and adults with CP requires a multidisciplinary approach, which necessarily includes orthopaedic surgery.

While there are many classification schemes, the most commonly utilized and most useful is the Gross Motor Function Classification Scale (GMFCS), which categorizes patients by functional level from I-V.¹ In broad terms, GMFCS I-III are independently ambulatory and GMFCS IV-V primarily utilize wheelchairs for mobility. Treatment for patients classified as GMFCS I-III—both surgical and medical—are aimed to improve gait efficiency and mobility while treatments for patients classified as GMFCS IV-V are aimed to improve comfort, sitting balance, and assisted care. Orthopaedic-related care for individuals with CP include physical and occupational therapy, bracing treatment, tone management, and orthopaedic surgery.

The majority of individuals with CP have spasticity, at least in part. Spasticity and increased tone can cause discomfort, decreased range of motion, difficulty with brace wear, and diminished mobility and should be addressed if it is functionally limiting. Tone may be managed by locally acting agents, botulinum toxin A, or globally by oral medications, most commonly baclofen, or surgery, intrathecal baclofen therapy or selective dorsal rhizotomy. In certain patients, both local and global management are warranted.

Botulinum toxin A selectively blocks the release of acetylcholine at the neuromuscular junction, allowing for muscle relaxation. It has been widely used off-label for pediatric and adult spasticity management for many years, but the FDA approved its use in lower extremity spasticity in children in 2016 and in adults in 2017. It is short acting and cannot prevent surgery, nor is it more effective than other treatment modalities—therapy, casting, or surgery. However, it can provide temporary control and delay surgical intervention in very young children.

Oral baclofen is most commonly a first-line treatment for global spasticity control. It works as an inhibitory neurotransmitter, blocking synaptic reflexes at the spinal cord. Taken orally, it can be sedating and may lead to tolerance in many patients. While it is frequently prescribed, a recent systematic review of six randomized controlled trials comparing oral baclofen to placebo or antispasmodics found poor evidence to support or refute the efficacy of this medication in terms of tone management or improving motor function in children and adolescents.²

A common alternative to oral baclofen is intrathecal baclofen therapy (ITB). ITB utilizes a surgically implanted battery-powered pump to deliver baclofen directly to the thecal space (Figure 1), bypassing the blood-brain barrier and significantly decreasing its systemic adverse effect profile. This therapy can safely be utilized in ambulatory and nonambulatory patients. Its efficacy in nonambulatory children was demonstrated recently. In midterm follow-up, researchers in Austria demonstrated significant sustained improvement in spasticity as measured by the modified Ashworth scale as well as improvements in quality of life, as measured by CPCHILD, a validated patient and/or parent-reported outcomes measure.³ However, these authors did report a nearly 30% complication rate with a 14% unexpected return-to-OR rate. Nonetheless, ITB remains a valuable treatment option for global spasticity control.

Selective dorsal rhizotomy (SDR) is an alternative surgical option in which a neurosurgeon selectively cuts dorsal nerve rootlets between L1 and S1, preventing sensory feedback from muscle spindles and effectively diminishing spinal reflexes. It has historically been indicated for ambulatory patients (GMFCS II-III), but it is becoming more popular in nonambulatory patients for comfort and ease of care, even in the setting of previous ITB therapy.⁴ However, the long-term outcomes of SDR are mixed. In a case-control study of adults with CP comparing those treated with SDR and those who did not have SDR, researchers found no difference in pain intensity, pain interference, or fatigue utilizing PROMIS (Patient-Reported Outcomes Measurement Information System) patient-reported quality of life measures, yet they noted a decrease in need for assistance and a lower perceived decline in functionality in the SDR group without any decrease in orthopaedic intervention.⁵ As such, similar to ITB, SDR is a viable treatment for global spasticity in appropriately selected patients.

The risk of developing scoliosis in this population is closely correlated to functional status. Patients who are nonambulatory have a significant risk of developing scoliosis; and those that are ambulatory have no increased risk compared with the general population.⁶ Typically, wheelchair modifications are made for relatively small (<50°) flexible curves, and surgery is reserved for curves measuring >50°, with the goal of halting progression, preserving seating balance, and supporting pulmonary and GI function. Surgical management typically consists of posterior spinal fusion with pedicle screws and sacral-alar iliac fixation in nonambulators. A recently published five-year outcome study revealed excellent initial correction and maintenance of scoliosis and pelvic obliquity correction without neurologic compromise or pseudarthrosis utilizing this surgical technique.⁷ Despite acceptable outcomes in terms of deformity correction, a recent review of the literature reported an associated complication rate of 38.1% with essentially equivocal findings in terms of quality of life/health outcomes following surgical intervention.⁸

However, a multicenter prospective registry study demonstrated consistent improvement in CPCHILD scores following spinal fusion in 199 included individuals.⁹ These authors stratified this cohort of GMFCS V patients by number of associated comorbidities (presence of a gastrostomy tube, tracheostomy, seizure disorder, nonverbal status) and found that risk of complication was directly correlated to each patient’s comorbidity burden. Those with no confounding comorbidities had a major complication rate of 12%, and those with three or more had a rate of 49%. Of note, baseline CPCHILD scores directly correlated with number of comorbidities, but there was no difference in the absolute improvement in scores from pre- to postoperative assessment between groups.

The risk for hip dysplasia/dislocation directly correlates with GMFCS level. Hip dislocation may lead to pain, functional impairment affecting the ability to sit, stand, or walk, and impaired quality of life. Along those lines, a prospective cohort study including 38 children with CP reported a negative correlation between migration percentage (MP) (radiographic measure which denotes the percentage of the femoral head lateral to the lateral aspect of the acetabulum relative to the entire width of the femoral head) and CPCHILD scores.¹⁰ Further, a recent population-based cohort study found a reported incidence of hip pain in 72% of adults with MP >30%.¹¹

Population-based hip surveillance and access to appropriate surgical management of hips-at-risk can significantly reduce or eliminate the incidence of painful, debilitating dislocations and need for unpredictable salvage surgery.¹² Regular surveillance allows for early intervention. Typically, soft-tissue surgery is recommended for migration percentage between 30% and 40% with associated adductor contracture, which includes adductor and iliopsoas lengthening. Osseous reconstructive surgery is recommended for migration percentages between 40% and 50% or more, which includes femoral varus derotational osteotomy with or without associated pelvic osteotomy. With correct indications, CPCHILD scores improve following surgery such that there is an increase in overall score by 0.2 points per additional 1% MP correction achieved, regardless of surgical procedure performed.¹⁰

These surgeries are not without risks, with one retrospective case-control series reporting a 65% complication rate following bony hip surgery, with 26% of patients experiencing multiple complications.¹³ Of these complications, only 15% required return-to-OR and an additional 2% were life-threatening (Clavien-Dindo III-IV), with no reported perioperative deaths.

Salvage surgery is indicated for those who present late with painful, debilitating hip dislocations. There are multiple options described in the literature, all of which have high complication rates. A recent systematic review of 28 studies reporting on salvage procedure outcomes revealed similar pain reduction following femoral head resection (FHR), valgus-producing osteotomy
(VO), total hip arthroplasty (THA), and shoulder prosthetic interposition (SPI) (90.4%, 88.4%, 93.8%, and 90.9%, respectively), all of which performed better than arthrodesis, with a reported pain reduction of 56.3%.¹⁴ Further, complication rates were similar between FHR, VO, THA, and SPI (24%, 33.3%, 35.3%, and 28.6%, respectively), and all were significantly lower than that of arthrodesis (106.3%). These authors did not advocate for a specific salvage procedure, but they did conclude that hip arthrodesis should be avoided in this population. In choosing a salvage procedure, the surgeon and family must weigh the risks and benefits of each option’s specific complication profile.

In ambulatory patients, hamstring spasticity and eventual contracture can lead to excessive knee flexion during stance, which increases pressure at the patellofemoral joint and increases the energy required for walking. First-line treatments include botulinum toxin A injections, stretching, and ground-reaction force ankle-foot orthoses. Surgical hamstring lengthening is typically recommended for worsening flexion without fixed contracture. Fixed contractures of small magnitude (<10°) in growing children may be addressed with guided growth¹⁵ or posterior knee capsulotomy, but larger contractures should be addressed with distal femoral extension osteotomy (DFEO) with or without patellar tendon advancement (PTA) (Figure 2). PTA has previously been shown to decrease midstance knee flexion at short- and midterm follow-up. Recently, a long-term follow-up study compared gait analysis and patient-reported outcomes in patients who underwent DFEO and PTA to those whose crouched gait was treated by other methods and found that those who underwent DFEO with PTA had improved stance phase extension and decreased knee flexion contractures, but there was no associated improvement in activity, participation, or knee pain.¹⁶

Some patients present with swing phase dysfunction secondary to rectus femoris spasticity. Historically, rectus femoris transfer has been recommended. However, a retrospective matched cohort study reported no difference in stride length, speed, peak knee flexion in swing, time to peak knee flexion, or Gait Deviation Index when comparing patients who underwent transfer with those who underwent lengthening at 1 year out.¹⁷ Simple lengthening is a viable alternative to transfer and should be considered.

Foot and ankle deformities are common in patients with CP. The goal in treatment is maintaining a plantigrade, painless foot that provides a stable base in stance. Common procedures include gastrocnemius recession and, less commonly, Achilles lengthening. However, Achilles lengthening should be reserved primarily for children with hemiplegic involvement and severe contractures as there is a risk of overlengthening and subsequent crouching inherent in isolated Achilles tendon lengthening. Furthermore, tibialis anterior tendon shortening should be considered in combination with Achilles tendon lengthening for severe equinus to ensure proper ankle dorsiflexion power after correction of equinus. A long-term study (mean 5.8-year follow-up) of 23 patients following this procedure (with and without concomitant lower extremity procedures) found significant, durable improvements in stance phase and swing phase dorsiflexion without need for postoperative bracing treatment.¹⁸

Pes planovalgus and pes equinovalgus are common in patients with spastic diplegia, while equinovarus deformities are more common in patients with hemiplegic involvement. In all cases, management begins with bracing treatment. Surgical management is reserved for patients with unbraceable deformities or in patients who are brace-intolerant. Equinovarus is treated surgically through a combination of muscular rebalancing and corrective osteotomy as needed. In addition to soft-tissue balancing and appropriate midfoot osteotomies, calcaneal lengthening is a common procedure for moderate planovalgus deformity, but a recent retrospective review of 20 patients (30 limbs) identified two preoperative radiographic markers closely correlated with radiographic undercorrection following calcaneal lengthening,¹⁹ suggesting that patients with an AP talonavicular angle >24° and a calcaneal pitch < -5° may require subtalar fusion. Alternatively, naviculectomy with midfoot arthrodesis may be a viable alternative in severe cases. A recently published series of 44 feet reported 81% excellent or good outcomes based on pain, radiographic union, and alignment of the forefoot and hindfoot at a mean of 5 years.²⁰

Single-event multilevel surgery (SEMLS), sometimes termed multilevel surgery (MLS), first described in 1985, has become the norm in the surgical management of ambulatory children with cerebral palsy, with multiple authors reporting durable improvements in gait profile postoperatively. A review of 231 patients with long-term MLS postoperative gait analysis and clinical examination (mean 9.1 years) revealed an average improvement in gait profile scores (GPS) of 5° (minimally clinically important difference: 1.6°) at short-term (1 year) follow-up, which was well maintained at an average of
9 years.²¹ In total, 76.6% of children maintained their GPS improvements. Of note, 39% required subsequent surgery other than removal of hardware, all of which were less invasive than the index procedure. This is in line with the series published by Rutz et al in 2013.²² In this patient population, the need for subsequent surgery following SEML/MLS surgery is not unexpected, and patients/parents should be counseled accordingly.

Myelomeningocele (MMC) is the most common and severe form of spina bifida characterized by a failure of closure of the neural tube in utero with extrusion of the underlying neural structures and resultant dysfunction. Open fetal repair is a new option in select patients with MMC and is associated with improved neurologic outcomes compared with postnatal repair.²³ Subsequent care for these patients requires a multidisciplinary approach as they have bladder, bowel, motor, and sensory dysfunction below the level of the neurologic lesion. Specific orthopaedic manifestations of MMC depend on neurologic level of involvement but include spinal deformity, hip dysplasia, joint contracture, limb deformity, and skin breakdown. Unfortunately, the natural history is consistent with an expected decline in functional status. Utilizing cross-sectional data from the National Spina Bifida Patient Registry, one study²⁴ reported a 60% rate of community ambulation at age 7 years, which decreased to only 35% in adults with MMC.

Of note, gradual deformity is a known sequela of flaccid paralysis, but rapidly progressive deformity may be associated with tethered cord syndrome, syringomyelia, or hydrocephalus, and should be evaluated by a neurosurgeon.

Spinal deformity, including scoliosis, kyphosis, and lordosis, is common and can be associated with seating imbalance, pressure sores, and respiratory compromise. A recent systematic review reported a pooled prevalence rate of 53%, which was directly correlated to neurologic level of involvement, suggesting the importance of frequent monitoring and early intervention for patients with higher levels of involvement.²⁵ Surgical complication rates as high as 53% were also reported, which includes an infection risk of 33.3%.²⁶

Common spine surgeries include tethered cord release, spinal fusion, and guided-growth procedures. Tethered cord release may result in stabilization or even improvement in milder curves (<50°), lower lesions,²⁵ and in patients older than 10 years.²⁷ Young children with moderate mobile deformities may be safely and effectively treated with dual growing rod constructs, allowing continued thoracic growth and pulmonary development.²⁸ Posterior spinal fusion and instrumentation may be utilized in moderate deformities in older children, while fixed severe kyphotic deformities may require kyphectomy and combined AP fusion.²⁵