Syndromes Important in Pediatric Orthopaedics

John M. (Jack) Flynn, MD

David L. Skaggs, MD, MMM

Michael G. Vitale, MD, MPH

Paul D. Sponseller, MD¹

William Mackenzie, MD, FRCSC,¹

¹Gurus:

General Principles of Managing Children With Syndromes

Evaluating children with genetic syndromes is a part of being a pediatric orthopaedist. In fact, you may be the first to consider the diagnosis. Although any particular syndrome is rare, when taken together, the incidence of orthopaedic genetic abnormalities is about 5 in 1000.¹ The point is this: You are going to have to deal with syndromes on a regular basis in pediatric orthopaedics.

Just because the child looks like the parent does not mean that they both don’t have a syndrome. Trust your gut instinct if a child looks “different” and consider a genetic consult. An astute pediatric orthopaedic surgeon can help entire families discover previously unrecognized genetic disorders.

When you encounter a congenital abnormality (e.g., congenital hand abnormality, clubfoot, hemivertebrae), ask yourself “Am I looking at a child with a syndrome?” Some syndromes are common enough to have their own multidisciplinary program (neurofibromatosis, for example). In such cases, these syndromes are easier to manage because there are a lot of interested experts who can lend a hand. Other syndromes are once-in-a-career rare. You may find that it is just you, a textbook, and perhaps an interested geneticist trying to do the job.

Even the brain of a pediatric orthopaedist has some limitations; remembering the name, orthopaedic manifestations, and associated systemic problems of every known syndrome that one might encounter will test those limitations. Therefore, to stay out of trouble, back up your pattern recognition skills with a good syndrome textbook,² as well as a computer in your clinic that has Internet access. With computer access, you can search for a syndrome by name or type OMIM into your favorite search engine to get the Online Mendelian Inheritance in Man website.

Steps to the Diagnosis of a Syndrome³

Obtain history and physical, with more gentle interrogation on the family history than an orthopaedic surgeon would normally do.
Give the parents an informal examination, looking for syndromic features.
Find an excuse to leave the room, consult a text (or internet), and construct a mental list for a reevaluation.
Go back in the room and reexamine the child, looking for the specific features mentioned in the book.
Obtain appropriate radiographs or other confirming diagnostic testing. 6. Consult genetics.
Set follow-up visit to synthesize consultant’s reports, all test results. Counsel family and construct orthopaedic treatment plan.

Always keep in mind that assigning a condition to a genetic cause is a loaded issue. It carries the possibility of blame assignment to one of the parents or to in-laws, with important implications for future offspring.

Don’t get caught up in the mental exercise of assigning a name and lose sight of the true goal: providing timely treatment for the child’s problems. Associated problems of other affected tissues and organ systems can be potential sources of trouble with syndromes. These other manifestations may suddenly become pertinent when the child is undergoing anesthesia for an orthopaedic procedure (Table 15-1). Guide parents to support groups so they are not alone.

TABLE 15-1 trouble When Operating on a Child With a Syndrome

Syndrome	Potential Trouble
Down	Congenital heart disease, upper cervical spine instability, infections, hypothyroidism
Morquio	C1-C2 instability, myelopathy
Marfan	Mitral valve prolapse, aortic dilatation
Neurofibromatosis	Hypertension (renal artery stenosis or pheochromocytoma)
de Lange	GE reflux and swallowing disorders add risk to anesthesia; self-mutilating behavior
Proteus	Intubation can be difficult due to overgrowth of structures adjacent to trachea
Larsen	C-spine instability, airway problems, tracheomalacia
Freeman-Sheldon	Oral and laryngeal involvement complicates anesthesia
Nail-patella	Abnormal renal function
Familial dysautonomia	Autonomic dysfunction, decreased stress tolerance, decreased sensitivity to pain
Rubinstein-Taybi	Congenital heart defects, problems with neuromuscular blocking agents, keloids, and scarring problems
Turner	Cardiac abnormalities
Prader-Willi	Morbid obesity is anesthesia risk
Beckwith-Wiedemann	Huge tongue can complicate intubation, airway post-op
VACTERL/VATER	Congenital heart defects, renal abnormalities
Goldenhar	Difficult intubation, congenital heart defects
Hurler-Scheie	C-spine abnormalities
Beal	Cardiac abnormalities
Homocystinuria	Thromboembolism
Ehlers-Danlos	Cervical instability, abnormal wound healing
Klippel-Trénaunay	Hemorrhages and thromboembolism, cellulitis, wound healing
Osteogenesis Basilar imperfecta	Basilar impression, elevated intraoperative temperature, accidental fractures from tourniquets and positioning

Top 11 Syndromes of Importance in Pediatric Orthopaedics

DOWN SYNDROME

Down syndrome is thought to be the most common congenital malformation (1 in 660 live births), so there is a high likelihood that most orthopaedists will care for several patients with this condition. Staying out of trouble with Down syndrome means focusing on the child and not abnormal radiographs. Down syndrome patients can have all kinds of unusual physical examination and radiographic findings and yet function at a very high level. Focus on the problems that will hamper function or cause pain.

Beware of spine problems in Down syndrome, including cervical instability, scoliosis, and spondylolisthesis. When evaluating cervical spine instability, don’t just look at C1-C2, look at occiput C1 as well (Fig. 15-1). A simplified and reasonable approach to cervical spine instability in Down syndrome is as follows:

Asymptomatic instability with ADI less than 10 mm: No treatment
Instability (ADI more than 10 mm) but no myelopathy: Check an MRI. If MRI shows cord impingement in flexion, then fuse. Increased signal in the cord is also a sign that there is abnormal motion and a relative indication for stabilization.
Instability with myelopathy: Fuse.

Figure 15-1 Be alert to the fact that the instability in the cervical spine of a child with Down syndrome can be at the occipitocervical junction, not just C1-C2. Note the relatively normal flexion film (A), but the movement of the occiput on C1 with extension (B).

Don’t recommend a fusion of C1-C2 just because the atlanto-dens interval is greater than 5 mm. Consider the risk and benefits carefully, because attempts at fusion are known to be associated with a very high complication rate.⁴ In addition to instability, these children can also develop deformity in the subaxial spine related to spondylolysis and precocious osteoarthritis. Hip instability in Down syndrome, including complete hip dislocation, can develop late (Fig. 15-2).

The hip can look good initially, but go on to complete dislocation between the ages of 2 and 10 years. The acetabulum of the Down syndrome hip can have a normal radiographic appearance, which belies the real problem: extraordinary patholaxity of the soft tissues. Additionally, behavior is a major component of problems in Down syndrome hips. Children can be habitual hip dislocators, creating a challenge similar to managing multidirectional shoulder instability in an adolescent with generalized ligamentous laxity. In general, the surgical management of hip instability in Down syndrome is extremely difficult. If you plan surgery, do osteotomies on both sides of the joint—femoral and iliac—because you
cannot rely on the soft tissues for stability. Long-term postoperative bracing may help to avoid redislocation. The complication rate of Down syndrome hip surgery can approach 50%.⁵

Figure 15-2 The hips in Down syndrome make their own rules. A: This boy presented at age 12 y with a few acute episodes of hip pain over the previous year, followed by refusal to bear weight for a few days, then a return to normal. The radiograph shows reduced, irregularly shaped femoral heads, and irregularly shaped acetabuli that seemed to provide good “coverage.” B: He returned at age 15 y with a painful, fixed dislocation of the left hip, subluxation of the right hip, and shallow, dysplastic acetabuli. Could this trouble have been avoided? Can it now be successfully treated?

Be alert for slipped capital femoral epiphysis (SCFE) in a Down syndrome patient who develops an abnormal gait or complains of knee or thigh pain. Some authors have suggested that hypothyroidism may play a role.⁶ It is well known that children with Down syndrome are more likely to get avascular necrosis (AVN) after an SCFE than otherwise normal children. A recent report showed AVN in five of eight patients.⁷

Most children with Down syndrome have hypermobile patellae. Given high rates of complications and recurrence of instability with surgical treatment, it is wise to restrict surgical treatment only to children who are symptomatic.

NEUROFIBROMATOSIS

There are two major types of neurofibromatosis: NF1 and NF2. Because the orthopaedic problems are confined to NF1, you should learn its diagnostic criteria (Fig. 15-3). Neurofibromatosis is relatively common (about 1 in 3000 infants), and many pediatric institutions have NF programs, so you are certain to see affected children. Be alert that NF can cause bone changes that are tumorlike in appearance (e.g., cysts or scalloping) and that neurofibromas can undergo malignant degeneration with an incidence of about 1%. Be alert for spinal manifestations of neurofibromatosis. The curves can be short and sharp, and there can be rib penciling and other findings (Fig. 15-4). Scoliosis and neurofibromatosis can start early and progress relentlessly. Bracing is usually ineffective. The enlarging neurofibroma can erode away at the pedicles (screw fixation can be difficult).

Fusion rates are lower in children with NF, and families should be counseled that more than one operation may be necessary. Dystrophic kyphosis is particularly dangerous (Fig. 15-6). This spinal deformity can lead to paralysis fairly rapidly. Historically, some have advocated for by both anterior and posterior fusion to increase fusion rates, but posterior-only operation has become more popular.⁸,⁹,¹⁰

Erosion of the pedicles in the cervical spine can lead to cervical instability over time (Fig. 15-7). Be sure to monitor involved children closely.

Figure 15-3 Axillary and inguinal freckling in neurofibromatosis. If there are freckles where the sun don’t shine, it is neurofibromatosis until proven otherwise. Axillary or inguinal freckles can serve as a quick screen for neurofibromatosis. (Used with permission of the Children’s Orthopaedic Center, Los Angeles.)

Figure 15-4 Scoliosis in a child with neurofibromatosis. Note the short, sharp curve that are classic in this NF spine trouble.

Figure 15-5 Advanced imaging can warn about the presence of rib penetration into the spinal canal in children with neurofibromatosis and keep you out of trouble in spine deformity correction.

Congenital pseudoarthrosis of the tibia is famous for the trouble that it causes. Perhaps the best testament to the trouble with congenital pseudoarthrosis is the fact that amputation was a common treatment (and still is for some cases).¹¹ It is important to remember that congenital pseudoarthrosis affects not just the tibia (Fig. 15-8) but can also affect the femur, clavicle, and either bone of the forearm. To stay out of trouble, don’t do an osteotomy through bone affected by neurofibromatosis. Clamshell bracing may be the best protection in the very young. A comprehensive discussion of the risks and benefits of different treatment methods is beyond the scope of this book. Variable success has been reported with the Ilizarov device and Spatial Frame,¹² microvascular bone transfer,¹³ and bypass grafting with preoperative bisphosphonates.¹⁴ To stay out of trouble treating

congenital pseudoarthrosis of the tibia, prepare yourself and the family for multiple procedures and follow-up to maturity before success is declared. These cases may be best handled by the small group of surgeons who have done several.

Figure 15-6 A: This 2-year-old boy with NF developed severe cervical kyphosis. B: An MRI showed a large neurofibroma anteriorly, with impingement on the cord in flexion. He was managed with anterior and posterior fusion with halo vest immobilization. (Courtesy of J. Dormans, MD.)

Figure 15-7 Subaxial cervical kyphosis resulting in cord compression and myelopathy in an 11-year-old with NF-1.

Figure 15-8 This 3-year-old with NF has a congenital pseudoarthrosis of the tibia that will be trouble for years to come. AP (A) and lateral (B) radiographs show a tibial pseudoarthrosis with an intact fibula. C, D: Prolonged casting had no effect. E, F: One year later, surgical management was begun. There was still no sign of healing, and the deformity had worsened. Many more procedures surely lie ahead. (Courtesy of R. Davidson, MD.)

ARTHROGRYPOSIS AND OTHER CONTRACTURAL SYNDROMES

Arthrogryposis is not a disease or diagnosis—it is a physical finding of rigid joint contractures. This category of syndromes includes dozens of distinctly different diseases including arthrogryposis multiplex congenita (AMC), Larsen syndrome, Freeman-Sheldon syndrome, and the pterygium syndromes. Children with AMC often present difficult multiple orthopaedic problems. To stay out of trouble, operate on joints early before adaptive changes secondary to the contractures make it difficult to get satisfactory results. Do osteotomies closer to the end of growth to avoid recurrence of deformity.

If you are consulted to see an infant with possible AMC, don’t prescribe neonatal range of motion or other infant physical therapy until birth fractures have been ruled out. In general, warn the parents and the physical therapist against aggressive and forceful manipulation that may cause fractures.

Closed reduction of a hip dislocation in a child with AMC is rarely successful. Recent reports of open reduction, followed by only a brief period of postoperative spica casting, seem to be giving better results than in the past (when orthopaedic surgeons often would wait to see which children will walk and which would not).¹⁵,¹⁶

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