Orthopedic Pediatric Review | Dr Hutaif Pediatric Ortho -...

According to several consensus statements, no child or adolescent athlete with a concussion should be allowed to return to play on the same day, regardless of severity. Second-impact syndrome refers to a second traumatic head injury that occurs while an athlete is still experiencing symptoms from the first injury. Young athletes are particularly vulnerable to second-impact syndrome. The mechanism by which this syndrome occurs likely is disruption of cerebral autoregulation, which may result in cerebral vascular congestion, diffuse brain swelling, and death.

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RESPONSES FOR QUESTIONS 2 THROUGH 6
1. Curettage and/or grafting
2. Radiofrequency ablation
3. Intravenous (IV) antibiotics
4. Incision, drainage, and IV antibiotics
5. Neoadjuvant chemotherapy followed by surgical reconstruction
6. Observation alone
For each clinical vignette seen in the figures, select the best initial treatment from the list above.

- Observation alone Question 3 of 100
Figure 3
1. Curettage and/or grafting
2. Radiofrequency ablation
3. Intravenous (IV) antibiotics
4. Incision, drainage, and IV antibiotics
5. Neoadjuvant chemotherapy followed by surgical reconstruction
6. Observation alone
PREFERRED RESPONSE: 6- Observation alone

- Radiofrequency ablation

- Intravenous (IV) antibiotics

Figure 2 depicts a typical unicameral bone cyst with a pathologic fracture. The decision to treat this lesion should be based on the amount of cortical thinning. If these lesions involve a pathologic fracture, many surgeons will treat them nonsurgically to see if the fracture stimulates healing of the cyst. If the cyst wall remains thin or the patient is symptomatic, then treatment is directed at decreasing cyst volume, increasing cortical thickness, and eliminating symptoms. This can be accomplished by curettage and grafting, injection with autogenous bone marrow, or grafting with 1 of the many available bone void fillers. In some cases, internal fixation may be required. This typically is accomplished with flexible intramedullary nails.
Figure 3 shows a typical nonossifying fibroma. These benign lesions are usually incidental findings on a radiograph and often resolve in adulthood. Treatment usually is not required, and these lesions typically do not produce symptoms.
Figure 4 shows an osteoid osteoma of the femoral neck. This is characterized by a central radiolucent nidus surrounded by reactive bone with increased radiodensity. These lesions are painful because of the large amount of prostaglandin they secrete. They temporarily respond to oral anti-inflammatory drugs. Treatment is directed at eliminating the nidus and can be done through curettage, but radiofrequency ablation, which allows for a minimally invasive approach, is often used today.
Figure 5 shows diskitis with vertebral osteomyelitis. The disease is characterized by fever and back pain. Movement is extremely uncomfortable for these children, and they may adopt unusual postures to alleviate pain. The MRI shows involvement of 1 vertebrae and an adjacent disk. Left untreated, this condition often spreads to involve multiple vertebrae and also can cause an epidural abscess. Treatment during the early stages is IV antibiotics. Many orthopaedic surgeons also use bracing to prevent late vertebral collapse.
Figures 6a through 6c show septic arthritis of the ankle with metaphyseal osteomyelitis. The recommended treatment is incision and drainage followed by IV antibiotics. MRI may be considered before surgery to assess for an associated osteomyelitis or abscess that may also necessitate surgical debridement. Increasingly, these scenarios are managed with a rapid transition to oral antibiotics.

Studies of titanium elastic nailing for femur fractures demonstrated a higher rate of complications, including angular deformity and construct failure, among patients weighing more than 50 kg (100 pounds). Other methods of fixation are recommended for these patients. Flexible nails are not commonly needed, but they also are not associated with a higher complication rate in children younger than age 6.5. Titanium elastic nailing works well in closed or minimally open transverse midshaft fractures, even in the setting of early or immediate weight bearing.

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Video 8b

The MRI scans show an advanced distal femur osteomyelitis with a substantial subperiosteal abscess. This necessitates open drainage; by definition, an abscess is avascular, so antibiotics cannot be delivered to the area without drainage.

Figure 9a

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CLINICAL SITUATION FOR QUESTIONS 9 THROUGH 12
Figures 9a and 9b are the radiographs of a 9-year-old boy who fell from the monkey bars and sustained a closed fracture of the elbow.

- Fall onto an outstretched elbow and hand

- instability of the fracture.

- lateral and medial pins.

This is a classic extension-type supracondylar elbow fracture typically caused by a fall on an outstretched hand. The medial comminution of this fracture renders it predictably unstable and susceptible to varus malunion. Extra attention with fixation is required. In general, use of lateral-entry pins alone is effective for most supracondylar humeral fractures. The best technique for fixation with lateral-entry pins only involves maximization of pin separation at the fracture site, engaging sufficient bone in both the proximal segment and the distal fragment and using more than 2 lateral entry pins (if needed) for stability. In the presence of medial comminution, medial fixation also may be necessary.
Brachial artery spasm is the usual cause of absence of radial pulse if capillary refill is normal. Close postsurgical monitoring is warranted after reduction and pinning.

Ideally, professional medical interpreters should be used in situations involving language difficulties. Printed instructions are helpful, but, if there is a language barrier, these instructions cannot substitute for conversing and answering questions. Asking the child to translate (no matter how fluent he or she may be) is suboptimal. Nonmedical staff may not be fluent enough to adequately translate medical terms.

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Figure 16b

RESPONSES FOR QUESTIONS 14 THROUGH 16
1. Aspiration, cultures, surgical irrigation and debridement, and intravenous (IV) nafcillin
2. Aspiration, cultures, surgical irrigation and debridement, and IV vancomycin
3. Aspiration, cultures, Lyme serology, and oral amoxicillin
4. Biopsy, culture, curettage, bone graft, and possible internal fixation
5. Physical therapy, ibuprofen, and an antinuclear antibody test
Select the most appropriate treatment above to address each clinical scenario below.

- Aspiration, cultures, surgical irrigation and debridement, and IV vancomycin

- Aspiration, cultures, Lyme serology, and oral amoxicillin

Figures 14a through 14e show a 13-year-old boy with osteomyelitis of the distal tibia and a large subperiosteal abscess. The patient has failed treatment with IV ceftriaxone, and methicillin-resistant Staphylococcus aureus infection is likely. Aspiration, cultures, irrigation and debridement, IV vancomycin, an infectious disease consult, and an evaluation for possible deep vein thrombosis is prudent initial treatment. Figure 15a through 15c show a 7-year-old girl who sustained a deer tick bite while vacationing in Connecticut. She has Lyme arthritis and a Lyme “bulls-eye” rash on the same leg. Aspiration, cultures, Lyme serology, and oral amoxicillin for 30 days is prudent initial treatment. Figures 16a and 16b are the radiograph and MR image of a 15-year-old dance athlete with a probable minor fracture via a benign cyst of the distal femur. The geographic cyst may be a nonossifying fibroma, eosinophilic granuloma, Brodie abscess, or simple bone cyst. Biopsy, culture, curettage and bone graft, and possible internal fixation is reasonable initial treatment.

Figure 17

Patients with a pathologic fracture of a unicameral bone cyst or simple bone cyst should first pursue nonsurgical treatment and 4 to 6 weeks of immobilization. Spontaneous healing occurs in fewer than 10% of patients, possibly due to cyst decompression. The most appropriate form of surgical treatment is controversial. Many substances have been injected with variable results. Injection with steroid, bone marrow, demineralized bone matrix, and calcium phosphate/calcium sulfate have been attempted. Curettage and bone grafting and
decompression have been attempted. Indications for treatment are based on cyst size, symptoms, and location. Unicameral bone cysts typically resolve as patients reach skeletal maturity.

Figure 18
CLINICAL SITUATION FOR QUESTIONS 18 THROUGH 23
Figure 18 is the lateral radiograph of the lumbar spine of an 11-year-old boy who has had lower back pain for 2 months. There is no history of injury. He denies radiating pain to his legs, numbness, weakness, and bowel or bladder changes. His usual activities include soccer practices and games 3 to 5 times per week. He has used over-the-counter anti-inflammatory medications, but has had no other treatment.

- hyperextension of the back.

- provide no significant benefit.

- activity modification and therapy to support the lumbar musculature.

- Age

- Lower than 5%

The radiograph of the lateral lumbosacral spine reveals an isthmic spondylolysis with a Meyerding grade 1 spondylolisthesis. The incidence of spondylolysis in the general population is around 5%, and grade 1 or 2 slips are present in the majority of children with a spondylolysis. Many cases of spondylolysis are painless and discovered incidentally, but, when painful, hyperextension of the lumbar spine may stress the area of the pars defect and exacerbate a patient’s symptoms. A diagnosis can usually be determined with a lateral radiograph of the lumbar spine. Although oblique lumbar radiographs are frequently ordered, several studies have shown that they do not increase diagnostic or prognostic accuracy. Progression of an isthmic spondylolysis, with or without a grade 1 or 2 listhesis, to a serious slip that might
necessitate surgical intervention is rare and occurs in fewer than 5% of patients. Chance for progression diminishes with age, with patients at highest risk prior to the adolescent growth spurt. Spondylolysis may have a genetic component; an increased prevalence has been found in some families and in some ethnic groups, especially among the Native American population.

Figure 24a

Figure 24b

In displaced extension-type supracondylar fractures, the neurovascular structures get kinked anteriorly or anteromedially related to the displacement. In almost all cases, there is a spontaneous resolution of this kink following closed fracture reduction.

Neurocognitive testing is a helpful tool in the management of concussions, but testing does not independently determine if an athlete has experienced a concussion or when he or she can return to play. Neuroimaging findings typically are normal in concussive injury. Loss of consciousness occurs in fewer than 10% of patients with concussions. A concussion diagnosis is difficult to determine because of the lack of objective clinical and/or imaging findings. In general, a concussion is a disturbance in brain function caused by a direct or indirect force to the head.

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RESPONSES FOR QUESTIONS 26 THROUGH 31
1. Plain radiographs
2. CT scan
3. MRI
4. Arthrogram
Which imaging method listed above is most appropriate for definitive diagnosis and management of each clinical scenario described below?

- MRI

- Plain radiographs

- CT scan

- MRI

- Arthrogram

Figure 26 shows lucent areas of both femoral condyles. This may represent a variation of ossification, in which case this boy’s knee pain is coincidental. Another possibility is atypical osteochondritis dissecans. An MRI will distinguish between the 2 entities and will guide treatment.
Figures 27a and 27b show healing rib and distal tibia fractures. These fractures likely are attributable to child abuse. A plain radiographic skeletal survey is sufficient for orthopaedic needs.
A triplane fracture of the distal tibia is revealed in Figure 28. A CT scan will quantify displacement and identify fracture fragments for planning of screw trajectories if open reduction and internal fixation is indicated (displacement > 2 mm).
In Figure 29, the linear lucency of the capitellum indicates an early osteochondritis dissecans. An MRI will allow staging of the lesion.
Figure 30 shows that the left radius and ulna do not align with the humerus; this is the likely result of a transphyseal fracture of the distal humerus. An arthrogram will outline the unossified distal humerus and allow for reduction. For an unstable neonate, this likely can be performed in the NICU.
Figures 31a and 31b reveal a widely displaced lateral condyle fracture for which open reduction and internal fixation is required. No advanced imaging is necessary.

Figure 32

This patient’s first femur fracture at age 7 was treated with a compression plate after he was struck by a motor vehicle. He sustained a second femur fracture at the end of the plate after a fall from a skateboard. Spica casting typically is recommended patients up to the age of 6 who weigh less than 25 kg. Tibial traction pins are not recommended for children because of risk for injury to the proximal tibial physis. A trochanteric entry rigid nail can be used, but a piriformis entry nail is not recommended for children because of risk for avascular necrosis of the femoral head. Removal of the plate and fixation with flexible titanium nails is a prudent option to fix the transverse fracture with a load-sharing device. Flexible nails are indicated for children weighing up to 50 kg.
CLINICAL SITUATION FOR QUESTIONS 33 THROUGH 36
A 10-year-old girl has right knee pain related to activity. An avid soccer player, she has noted pain after the first 15 minutes of running but no swelling or mechanical symptoms. Radiographs show a large 2-cm osteochondritis dissecans (OCD) lesion.

- Activity restriction and follow-up radiographs in 3 months

- Activity restriction and follow-up radiographs in 3 months

- Arthroscopic evaluation and fixation

In a skeletally immature patient with OCD and minor symptoms, the lesion can be observed and healing obtained with activity limitations if the cartilage is stable (but this cannot be determined radiographically or clinically). Activity restriction and serial follow-up are appropriate if an MRI reveals a stable lesion. MRI is indicated when there is concern that a lesion may be unstable. Surgical treatment depends on MRI findings.
Observation is recommended for OCD lesions in growing patients for 6 months because healing has been observed. Early surgical procedures, although they may be needed in the future, are not appropriate for patients with well-controlled symptoms.
If symptoms continue for longer than 6 months, arthroscopic drilling is not indicated for unstable OCD. The appropriate treatment is OCD fixation. Debridement is not appropriate with a stable lesion.
Evaluation of the fixation and stability of the lesion with advanced imaging after weight bearing and therapy initiation is the most appropriate option. Manipulating the knee without determining whether the stiffness is attributable to subsidence of the fixation or mechanical block is not appropriate. After 4 months, aspiration of a hematoma (if still present) would not yield much benefit. More therapy is not likely to be useful when a patient is attending therapy regularly and working on a home program.

Figure 37a

Figure 37b

Figure 37c

Figure 37a shows a completely displaced supracondylar humerus fracture. The first step in the situation described, which involves a pink pulseless hand, is to perform an urgent closed manipulation and pinning. The vascular examination should be reassessed following the reduction. When adequate reduction has been achieved and the pulse remains nonpalpable but the hand is pink and capillary refill is normal, the fracture may be splinted and the patient observed closely in the hospital. Arteriography is not useful and may delay revascularization or increase vessel spasm. Although some investigators have concluded that exploration of the brachial artery may be indicated, the algorithm that includes observation only is the most supported and the most commonly practiced treatment. The radiographs show adequate reduction and fixation without medial widening at the fracture site, which might indicate a site of brachial artery entrapment. Therefore, pin removal and fracture rereduction is not indicated.
RESPONSES FOR QUESTIONS 38 THROUGH 45
1. Sclerosis of the proximal femoral epiphysis with subchondral lucency
2. Abnormal femoral head-neck junction offset
3. Widening of the proximal femoral physis with normal femoral head-neck junction offset
4. Absence of the proximal femoral epiphysis secondary ossification center
For each clinical scenario below, select the most likely associated radiographic finding from the list above.

- Sclerosis of the proximal femoral epiphysis with subchondral lucency

- Abnormal femoral head-neck junction offset

- Absence of the proximal femoral epiphysis secondary ossification center

- Abnormal femoral head-neck junction offset

- Widening of the proximal femoral physis with normal femoral head-neck junction offset

- Sclerosis of the proximal femoral epiphysis with subchondral lucency

- Abnormal femoral head-neck junction offset

Early radiographic findings of avascular necrosis (AVN) of the hip include sclerosis and a subchondral lucency. A common presentation of Legg-Calve-Perthes disease (idiopathic pediatric hip AVN) is intermittent pain in the thigh, groin, or knee with an examination localizing to the hip; a Trendelenburg gait or sign; and painful, restricted passive hip range of motion. AVN also may be observed in association with a slipped capital femoral epiphysis (SCFE). AVN risk is highest in the setting of an unstable SCFE (10%-60%); risk is 0% to 1.4% when the SCFE is stable. A multicenter review of the modified Dunn procedure for treatment of unstable SCFE noted an AVN rate of 26%.
The most common deformity associated with SCFE is proximal femoral varus, flexion, and external rotation leading to an abnormal femoral head-neck junction offset. This causes a loss of passive hip flexion and internal rotation and the phenomenon of obligate external
rotation with flexion. The residual deformity frequently results in femoroacetabular impingement. Labral tears also are associated with cam impingement secondary to underlying osseous abnormalities including abnormal femoral head-neck junction offset.
Endocrinopathies potentially are associated with SCFE because of hormone-related physeal changes and subsequent mechanical insufficiency of the proximal femoral physis. With renal osteodystrophy, the physeal widening results from secondary hyperparathyroidism and progressive proximal femoral deformity may develop. Optimal medical management of hyperparathyroidism is essential. Surgical stabilization via in situ fixation of the proximal femur is indicated when SCFE is diagnosed.
The proximal femoral epiphysis secondary ossification center commonly appears between the ages of 4 and 7 months. In the setting of developmental hip dislocation, the appearance of the secondary ossification center is commonly delayed. After closed or open reduction of developmental dysplasia of the hip, failure of the femoral head ossific nucleus to appear within 12 months following the reduction is a sign of proximal femoral growth disturbance and AVN.

Figure 46a

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Figure 46d

This girl sustained a fracture dislocation of the elbow with a severely displaced and rotated radial neck fracture. Required treatment was open reduction and internal fixation (ORIF). Less severely displaced radial neck fractures can be treated with closed reduction, percutaneous pinning, or flexible nail manipulation. In this scenario, interposed capsular tissue and rotation of the radial head were indications for ORIF. ORIF is associated with a higher risk for poor
outcomes. Complications following ORIF of radial neck fractures in children include posterior interosseous neuropraxia, valgus angulation, premature closure of the radial head physis, AVN of the radial head, nonunion, and elbow stiffness. Stiffness is most common. Compartment syndrome, infection, and anterior interosseous nerve palsy are less common complications.

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Figure 47b
CLINICAL SITUATION FOR QUESTIONS 47 THROUGH 50
A 6-year-old boy arrives at the emergency department with forearm pain. Today he was picking up his backpack when he felt a pop in his forearm that resulted in the current injury. His history is significant for 6 other fractures treated nonsurgically. His mother states that she had 15 fractures during childhood but is healthy now. Both the boy and his mother have blue sclera. Figures 47a and 47b are the radiographs of his injured forearm.

- The boy likely has osteogenesis imperfecta (OI).

- A genetic defect in the type I collagen gene

- there is a sudden change in elasticity between the plated and unplated bone.

Many patients with mild dominant OI (the most common type) appear “normal,” and a diagnosis cannot be made without a careful personal history, family history, and observance of blue sclera. More than 3 fractures during childhood places someone outside of the mean and should merit further investigation. There is no sign of rickets on this radiograph (physeal widening/cupping). Similarly, the history and examination finding of blue sclera in the patient and his mother should raise concern for OI. Many parents of children with OI have inappropriately been accused of abuse despite obvious examination, radiograph, and family history findings that suggest OI. Low-energy mechanisms that create displaced fractures are a hallmark of OI and do not in isolation raise suspicion for nonaccidental trauma.
Based on the history and examination, mild-form OI caused by a defect in the type I collagen gene is most likely. Defects in type II collagen genes affect articular cartilage and cause epiphyseal dysplasia. Defects in the LEPRE cause severe-form OI involving clinically bowed limbs, marked short stature, and white sclera. There is no sign on radiographs of rickets, so severe vitamin D deficiency is not present. The history, examination, and radiographs all point toward OI/osteoporosis rather than nonaccidental trauma.
Peri-implant fractures occur because of a difference in elasticity between the bone with implants and the bone adjacent to it without implants. This is particularly important in the setting of osteoporotic bone in which the difference in elasticity and rigidity will be much more pronounced than in normal bone. Load-sharing implants are preferred when possible. The original fracture occurred proximal to the current fracture in the middle of the plated bone and looks healed with no sign of infection.
This fracture is in unacceptable alignment with subluxation of the radiocapitellar joint. The plates are bent, so closed reduction will not solve the alignment problem. In early childhood, load-sharing implants (flexible rods or wires) should be used to solve the elasticity mismatch that contributed to the current fracture.

Figure 51a

Figure 51b

Figure 51c
CLINICAL SITUATION FOR QUESTIONS 51 THROUGH 54
Figures 51a through 51c are the radiographs of an 8-year-old boy with a shoulder deformity and limited cervical range of motion. He has no significant medical problems and plays baseball, pitching with his right arm. His active shoulder abduction is 180 degrees on the left and 150 degrees on the right.

- Cardiac, renal, and auditory

- spine.

- avoidance of contact or collision sports.

The figures are characteristic of a child with Klippel-Feil syndrome (congenital cervical spine abnormalities) in association with congenital scoliosis in the upper thoracic spine and a right-sided Sprengel deformity (congenital elevation of the scapula). Sprengel deformity occurs in as many as 30% of children with Klippel-Feil syndrome. Other congenital conditions that are commonly associated with Klippel-Feil, and that should be screened for, include deafness in 30%, genitourinary abnormalities in 25% to 35%, and cardiovascular abnormalities in 4% to 29% of children with Klippel-Feil syndrome.
In Sprengel deformity, there is usually a tether called the omovertebral connection between the abnormally elevated scapula and the spinous processes in the upper thoracic region. This tether is most commonly bony but also may be cartilaginous or fibrous. Although there also may be abnormalities in the ribs, clavicle, or humerus, they are morphologic abnormalities only, not tethers.
Patients with Klippel-Feil syndrome should be discouraged from participating in contact or collision sports if they have a massive fusion of the cervical spine, any involvement of C2, or limited cervical motion. Fusions at 1 or 2 interspaces below C3 and normal cervical motion do not preclude participation in activities. A Sprengel deformity may limit abduction of the shoulder and normal racquet or throwing mechanics, but, in the absence of pain, is not a contraindication to attempted participation.
Klippel-Feil syndrome affects a heterogenous cohort of patients and different inheritance patterns have been seen, including autosomal-dominant and autosomal-recessive types, with varying levels of penetrance. The first human Klippel-Feil syndrome locus was identified on chromosome 8 and is called SGM1. Other candidates for mutations in Klippel-Feil include PAX genes and Notch pathway genes. In general, the involved genes help regulate the formation and segmentation of the vertebrae.
Between days 20 and 30 following conception, the paraxial mesoderm subdivides into segments called somites. As they mature, somites develop into 3 layers called the sclerotome, myotome, and dermatome. The sclerotome undergoes a process of resegmentation during which the caudal section from 1 somite joins with the rostral section of the immediately caudal somite to form the vertebral bodies. It is during the processes of segmentation and resegmentation that the abnormalities leading to Klippel-Feil syndrome occur. Gastrulation refers to the phase early in embryonic development when the single-layered blastula is reorganized into a trilaminar structure with 3 germ layers: the ectoderm, mesoderm, and endoderm. Neurulation refers to the process by which the notochord induces formation of the neural tube from the neural plate, forming the brain and spinal cord.

Figure 55a

Figure 55b

Figure 55c

This injury is a type III supracondylar humerus fracture with posterolateral displacement. The area of ecchymosis is anteromedial, corresponding to the proximal spike of the humeral metaphysis. The brachial artery is likely tented over this spike, leading to diminished perfusion. The median nerve also resides in this area, and any neurological deficit is likely in its most vulnerable fibers, those of the anterior interosseous nerve (AIN). The AIN contains no sensory fibers, and its motor function involves flexion of both the thumb IP joint and the index distal IP joint.
First dorsal web space anesthesia and an inability to extend the fingers would indicate radial nerve neuropraxia, which would be more likely with posteromedially displaced fractures and lead to anterolateral ecchymosis. Finger abduction is controlled by the ulnar nerve, which most often is injured in flexion injuries and iatrogenically by medially placed pins.

Figure 56

At 3 years of age, children do well with nonsurgical treatment with early spica casting and early mobilization. There is no indication to perform surgical stabilization in such a closed isolated injury. The fracture is not shortened unacceptably according to clinical practice guidelines, and traction for this fracture is unnecessary. Traction also may be problematic for the family and healthcare system.
RESPONSES FOR QUESTIONS 57 THROUGH 62
1. Cortical thickening in the region of the lesion
2. Erosive metaphyseal lesion with loss of cortical integrity
3. Normal bony anatomy on radiographs
4. Diffuse articular erosion with loss of joint space
5. Round, expansive, well-circumscribed metaphyseal lesion with thinning of the cortex
6. Eccentric well-circumscribed metaphyseal lesion with a scalloped border
Match the orthopaedic condition described below with the expected radiographic finding listed above.

- Normal bony anatomy on radiographs

- Erosive metaphyseal lesion with loss of cortical integrity

- Normal bony anatomy on radiographs

- Cortical thickening in the region of the lesion

- Round, expansive, well-circumscribed metaphyseal lesion with thinning of the cortex

Early osteomyelitis and septic arthritis appear as normal bony anatomy on radiographs, with perhaps only soft-tissue swelling seen. Radiographic changes with metaphyseal erosion appear in a delayed fashion, often after 7 or more days in indolent infections, but may present earlier in association with virulent infections such as methicillin-resistant Staphylococcus aureus. Osteoid osteoma has a radiolucent small nidus that may be difficult to see on radiograph; however, chronic cases cause marked cortical hypertrophy. Unicameral bone cysts are expansile metaphyseal lesions that are never wider than the physis. They are symmetric, well circumscribed, and can have cortical thinning. When fractures through the cyst are
present, the fallen leaf sign is visible as cortical fragments fall to the bottom of the cyst. Nonossifying fibromas are eccentric metaphyseal lesions with scalloped borders.

CA-MRSA is a growing problem in the United States. Groups at risk for CA-MRSA include athletes in contact sports and children in daycare. Tennis players, golfers, and runners are at lowest risk because their sports do not require close contact with teammates or competitors. Outbreaks have been noted in Alaskan native, Native American, and Pacific Islander minority populations.

Figure 64a

Figure 64b

Figure 64c

Figure 64d
CLINICAL SITUATION FOR QUESTIONS 64 THROUGH 68
Figures 64a through 64d are the radiographs of an 11-year-old boy with a prolonged history of activity-related ankle pain. An examination is notable for restricted subtalar motion and moderate pes planovalgus.

- tarsal coalition.

- Autosomal dominant

- FGFR-1, FGFR-2, and FGFR-3.

- CT scan

Radiographs reveal a talocalcaneal coalition. The incidence of tarsal coalition in the general population ranges between 2% and 13%. The incidence of tarsal coalition among patients with FGFR-related craniosynostosis syndromes is much higher than among the general population. Tarsal coalitions have been noted in FGFR-1-, FGFR-2-, and FGFR-3-related craniosynostosis syndromes of Apert, Pfeiffer, Crouzon, Jackson-Weiss, and Muenke, but not in Beare-Stevenson or Crouzonodermoskeletal syndromes. The FGFR genes are involved in cell proliferation, differentiation, migration, apoptosis, and pattern formation.
Additionally, nonsyndromic familial coalitions have been described with autosomal-dominant patterns of inheritance.
Cross-sectional imaging should always be obtained prior to resection of a radiographically evident coalition to define the extent of the coalition and determine the coexistence of an additional coalition. CT scan is the gold standard test; however, MRI can be helpful to define a suspected fibrous coalition if a CT scan is nondiagnostic. A bone scan may be useful if pain or history is atypical for a symptomatic coalition. Laboratory tests such as CBC, ESR, CRP, ANA, and RF may be indicated if the imaging evaluation does not confirm a tarsal coalition and if there is concern for malignancy, infection, or inflammatory arthritis.
Investigators have suggested that larger talocalcaneal coalitions with surface areas larger than 33% to 50% of the size of the posterior facet are unsuitable for resection and primary arthrodesis should be considered. However, a study by Koshbin and associates found that with long-term follow-up, favorable functional outcomes were seen even with resections of large talocalcaneal coalitions occupying more than 50% of surface area.

K. kingae is variably invasive and is a facultative anaerobic gram-negative bacillus. K. kingae is a common bacteria that causes osteoarticular infections in young children. Presentation is often delayed because of the moderate course of the infection. Ten percent of young children are colonized with K. kingae. Colonization occurs in the oropharynx and is a prerequisite for invasive K. kingae septic arthritis. The PCR test screens for the RTX protein,
the factor responsible for the bacteria’s cytotoxicity. Among children in daycare centers, 28% are colonized. The sensitivity of the oropharyngeal swab PCR has been reported at 100%, and the specificity is 90.5%.
RESPONSES FOR QUESTIONS 70 THROUGH 74
1. Thrower's elbow/physeal irritation of the medial epicondylar physis
2. Osteochondritis dissecans (OCD)
3. Supracondylar humeral stress fracture
4. Patellar sleeve fracture
5. Distal femoral physeal fracture
6. Sinding-Larsen-Johansson syndrome/inferior pole patella apophysitis
7. Medial meniscal tear
8. Patellar tendon rupture
9. Patellofemoral pain syndrome
10. Popliteal cyst
11. Osteochondroma
12. Synovial sarcoma
Match the appropriate orthopaedic condition above with the clinical scenario below.

- Osteochondritis dissecans (OCD)

- Patellar sleeve fracture

- Medial meniscal tear

- Popliteal cyst

OCD of the capitellum presents in throwing athletes with lateral pain and a flexion contracture vs medial epicondylar physeal overuse, which is associated with medial pain and possible widening of the physis on radiograph.
Midsubstance patellar tendon rupture is rare in skeletally immature patients; usually, disruption of the extensor mechanism occurs either through a tibial tubercle physis fracture or a patellar sleeve fracture because these cartilaginous areas are structurally weaker than the patellar tendon. Often, only a small bony fleck is seen, and the main fracture is cartilaginous.
Medial joint line pain and a positive McMurray test result are most consistent with a medial meniscal tear. Sinding-Larsen-Johansson syndrome would produce soreness over the inferior pole of the patella.
Because the knee mass is painless and cystic, synovial sarcoma is unlikely because these sarcomas are solid, progressive, and painful. An osteochondroma would be a bony protrusion and would not transilluminate, which is a feature of cystic masses. It also would not change size. Popliteal cysts are common in children, with most resolving spontaneously over several years.
Patellofemoral pain syndrome can cause mild anterior compartment crepitation but does not produce point tenderness over a specific apophysis like Sinding-Larsen-Johansson syndrome (inferior pole of patella tenderness). It is common in pubertal girls and is treated with rest, ice, nonsteroidal anti-inflammatory drugs, and therapy exercises with resolution in most cases.

Figure 75a

Figure 75b

The injury shown is a flexion-type supracondylar humerus fracture. The most commonly interposed anatomic structure is the ulnar nerve. The brachialis muscle is often interposed in extension-type fractures, as are the median nerve and radial artery. The radial nerve is at risk for entrapment in a humeral shaft fracture or distal third humeral fracture.

Figure 76
CLINICAL SITUATION FOR QUESTIONS 76 THROUGH 80
Figure 76 is the clinical photograph of an infant with foot deformities.

- a PITX1 mutation.

- absence of the anterior tibial artery.

- tarsal bones.

- noncompliance with postsurgical bracing.

Single nuclear polymorphism (SNP) on chromosome 12q24.31, an intergenic SNP, is the PITX1-TBX4 transcriptional pathway that codes for hindfoot formation and is associated with clubfoot. The COLIA-1 gene is related to osteoporosis. Mutations in EXT genes that control formation of tumors cause multiple hereditary exostosis. Mutations in the COL5A or COL3A genes are associated with Ehlers-Danlos syndrome. All idiopathic clubfeet involve abnormalities of or around the talus.
The classic Ponseti technique is associated with a low recurrence rate when followed precisely. The most common reason for recurrence is noncompliance with postsurgical bracing. The initial treatment for recurrence after Ponseti casting is recasting.
NCOA2 fusion transcripts has been noted in mesenchymal chondrosarcoma. Ring chromosomes with CDK4 and MDM2 amplification may be identified with low-grade central osteosarcoma or parosteal osteosarcoma. Fusion transcripts of CDH11-USP6 have been observed in aneurysmal bone cysts.

Figure 82a

Figure 82b

Video 85
CLINICAL SITUATION FOR QUESTIONS 82 THROUGH 85
Figures 82a and 82b are the radiographs of a 10-year-old girl who was an unrestrained back seat passenger in a motor vehicle collision. Her sole injury is to her left leg. She has a deformed valgus knee with lateral swelling and bruising, and no wound is visible. Upon examination, she has symmetric pulses to her right leg but diminished sensation on the dorsum of the foot and in the first web space. She cannot dorsiflex her left foot or toes but can plantar flex and invert them. Weak ankle eversion is present. Sensation to the plantar foot, medial ankle, and lateral ankle is intact. She likely will reach skeletal maturity at age 14.

- Hypertrophic zone

- Common peroneal nerve

- Observe the nerve injury with further workup/intervention only if there is no sign of nerve recovery by 3 months after surgery

The hypertrophic zone is the weakest biomechanical zone of the physis and is most likely to fracture. The deep peroneal nerve supplies motor innervation to the ankle and toe
dorsiflexors (anterior compartment) and the first web space, which, in this history, have deficits. The superficial peroneal nerve supplies sensation to the dorsum of the foot and motor to the lateral compartment peroneal musculature (ankle evertors), which also has deficits. The injury must involve both peroneal branches (the common peroneal nerve). Because sensation to the sole of the foot and toe/ankle plantar flexion is intact, the tibial nerve is intact.
Because the nerve was visualized intact, a neuropraxia is the most likely type of nerve injury. This should recover in time and does not necessitate urgent exploration. In pediatric patients, an advancing Tinel sign and partial nerve recovery by 3 months is expected and can be followed clinically. If there is no sign of nerve recovery, an electromyogram should be ordered with consideration for nerve exploration if there is no sign of reinnervation. There is no sign of compartment syndrome because the patient has an unchanged neurologic deficit, is comfortable, and has no pain with passive range of motion.
These injuries are associated with a very high rate of growth arrest (up to 80% in some studies). The CT scan shows an asymmetric growth arrest, which suggests angulation through the distal femur.

A stress fracture of the femoral neck or pelvis should be ruled out in this patient. She should be placed on crutches and not allowed to run. The consequences of missing such a diagnosis can be devastating. Superior cortical femoral neck stress fractures are tension injuries and can progress to a complete fracture and avascular necrosis. Surgical fixation may be indicated. Plain radiographic findings often do not appear until late in the clinical course. MRI is more accurate, more specific, and is superior to radionuclide bone scanning for the diagnosis of stress fracture in young endurance athletes. MRI detects early changes in osseous
stress injury and allows precise definition of the anatomy and extent of injury. This patient may have the female athletic triad: disordered eating, amenorrhea, and osteoporosis. However, the workup for this condition (including a possible DEXA scan) may be delayed until after the stress fracture is diagnosed and treated.

Figure 87a

Figure 87b

Figure 88

Figure 89

Figure 90
CLINICAL SITUATION FOR QUESTIONS 87 THROUGH 90
Figures 87a and 87b are the clinical photograph and radiograph of a 14-year-old high school football player who fractured his dominant right clavicle. The skin is closed and vascular and neurologic examination findings are normal.

- A sling and careful follow-up

- Observation and careful follow-up

- Allow baseball as tolerated and careful follow-up

This patient has a closed midshaft clavicle fracture with significant displacement that has healed and remodeled nicely with nonsurgical treatment. Functional disability or nonunion after nonsurgical treatment of clavicle fractures in adolescents is rare. Schulz and associates showed no differences in pain, strength, range of motion, or subjective outcome scores between injured and uninjured limbs treated nonsurgically to address displaced, shortened midshaft clavicle fractures in adolescents. Bae and associates demonstrated that clavicle fracture malunions in adolescents do not cause loss of motion or strength.

Figure 91a

Figure 91b

Figure 92

Figure 93

Figure 94a

Figure 94b

Figure 94c

Figure 95a

Figure 95b

Figure 96
RESPONSES FOR QUESTIONS 91 THROUGH 96
1. Chromosome 17 mutation
2. MYH3 mutation
3. Embryonic vascular interruption
4. Infantile vascular interruption
5. Chromosome 11 mutation
6. Sporadic inheritance
Select the appropriate etiology listed above for each pictured syndrome.

- Embryonic vascular interruption

- Infantile vascular interruption

- Sporadic inheritance

- MYH3 mutation

- Chromosome 17 mutation

Poland syndrome and Sprengel deformity (Figure 91) are hypothesized to occur as the result of interruption of the embryonic subclavian blood supply. Poland syndrome occurs proximal to the internal thoracic artery and distal to the vertebral artery; Sprengel deformity is thought to occur via interruption of the subclavian, internal thoracic, or suprascapular artery.
Hair tourniquet syndrome (Figure 92) occurs most often in children younger than 2 years of age. Human hair, which is often not seen in the band, circumferentially strangulates a digit or extremity. If not recognized and treated promptly, auto-amputation distal to the hair tourniquet may occur.
No known genetic or environmental factors are associated with the etiology of Fibular hemimelia (Figure 93). Nearly all of these patients have an absent Anterior Cruciate Ligament. Additional associations include, absent rays of the foot, tarsal coalition, hypoplastic or aplastic fibula, leg-length discrepancy, femoral and tibial hypoplasia and lower extremity angular deformity.
Freeman-Sheldon syndrome, Sheldon-Hall Syndrome and Distal arthrogryposis (Figure 94) have been associated with mutations of MYH3, the gene which codes for myosin heavy chain 3.
Fifty percent of patients with Neurofibromatosis type 1(NF1) (Figure 95) will have musculoskeletal manifestation of the disease; most commonly scoliosis and pseudarthrosis of the tibia. Twenty percent of patients with NF1 present with scoliosis. Dystrophic scoliosis is typical of NF1. Dystrophic features of include: scalloped vertebra, penciled ribs, severe
rotation, sharp and short (4-6 vertebrae) kyphoscoliosis. Although NF1 has autosomal dominant inheritance, 50% of new cases are due to sporadic mutation. The NF1 gene on chromosome 17 codes for neurofibromin, a tumor suppressor.
Beckwith-Wiedemann syndrome (Figure 96) is associated with chromosome 11 mutations near the IGF gene. Neonatal hypoglycemia; macroglossia; visceromegaly; hemihypertrophy; and embryonal tumors, especially Wilms tumor, are associated with mutations of chromosome 11.

45

Figure 100a

Figure 100b
CLINICAL SITUATION FOR QUESTIONS 97 THROUGH 100
A 12-year-old boy with a 2-day history of fever and right knee pain is admitted to the pediatric service. You are asked to provide an orthopaedic consultation. The patient denies recent trauma. His temperature is 39.4°C and his gait is antalgic. There is no palpable knee effusion and mild tenderness and swelling of the distal thigh area. Hip and knee range of motion is not limited. Radiographs of the femur are unremarkable. His white blood cell (WBC) count is within defined limits, and the differential shows 80% segmented neutrophils. His erythrocyte sedimentation rate is 46 mm/h (reference range [rr], 0-20 mm/h), and his C-reactive protein level is 5.6 mg/L (rr, 0.08-3.1 mg/L).

- Blood cultures

- initiation of intravenous (IV) antibiotics.

- Methicillin-resistant Staphylococcus aureus (MRSA).