Pamela Horn, MS


 	Figure 1 – Elementary school zip lines, such as the one shown here, are responsible for an increasing number of injuries in children.

While playing on the school playground, a 10-year-old boy decided to try a zip line (

). He grabbed the pulley and slid down the cable. When the pulley came to a stop, he fell off and sustained a right ankle injury. In the emergency department (ED), the diagnosis was a right distal fibula shaft fracture and distal/medial Salter-Harris type II tibia fracture (

). The fractures were nondisplaced, and the child's right lower extremity was placed in a long leg cast, which was replaced 3 weeks later with a short walking cast; he was transitioned to a walker boot 2 weeks after that. The fractures healed without complications. Because of possible injury to the growth plate, follow-up in 6 to 9 months was needed to ensure there was no physeal arrest.

About 200,000 children with injuries related to playground equipment are treated in hospital EDs in the United States each year; 75% of these injuries are a consequence of falls.

 Seventy percent of children between the ages of 5 and 12 years-including roughly equal numbers of boys and girls-sustain playground injuries.

) radiographs taken in the emergency department show a right distal fibula shaft fracture and distal/medial Salter-Harris type II tibia fracture.

The incidence of zip line injuries in children has increased in the past few years in the inpatient and outpatient settings. The trauma registry data from 1 urban pediatric hospital show that between 2006 and 2008, 10 children aged 5 to 12 years were hospitalized for zip line injuries. Most of the patients had upper extremity injuries and many required surgical intervention. In 2009 alone, the number of children with zip line injuries was higher than the total number from the previous 3 years; trauma registry data and clinic records note more than 15 combined inpatient and outpatient visits.

A zip line (flying fox, zip wire, track ride, aerial runway, or rope slide) requires significant upper body strength and the judgment to know when it is safe to let go.

 recommend that children be at least 5 to 12 years old before using zip lines.

Another recommendation is that the height of the equipment be about 5 to 6.5 ft, which accommodates the average height range seen in 5- to 12-year-olds.

 However, the equipment height at which a child would be safely protected against a fall depends in part on the depth of the approved cushioning material and in part on the type of cushioning material used. Many playground injuries are caused by an insufficient amount of ground covering, not a complete lack of ground covering. Playground safety experts recommend the use of loose-fill or synthetic material to provide cushioning. When 9 in of cushioning material is used (the minimum recommended amount), the maximum safe "fall height" is 10 ft with shredded/recycled rubber, 4 ft with sand, 5 ft with pea gravel, 7 ft with wood mulch, and 10 ft with wood chips.

It is important for children to be active and play, and zip lines are fun and their novelty is a welcome change. However, children and their caregivers must be made aware of the risks and recommendations regarding the use of zip lines and be cautious when playing on any new playground apparatus.

 Vollman D, Witsaman R, Comstock RD, Smith GA. Epidemiology of playground equipment-related injuries to children in the United States, 1996-2005. 

 US Consumer Product Safety Commission. Public Playground Safety Handbook. 

 US Consumer Product Safety Commission. Outdoor Home Playground Safety Handbook. 2005. 

 Nixon JW, Acton CH, Wallis BA, et al. Preventing injuries on horizontal ladders and track rides. 

Articles

While playing on the school playground, a 10-year-old boy decided to try a zip line. He grabbed the pulley and slid down the cable. When the pulley came to a stop, he fell off and sustained a right ankle injury.

A New Zip in Playground Injuries


 A 17-year-old girl presented for evaluation of right hip pain. Several months earlier she had incurred a twisting injury to her hip when she landed from a jump while dancing. She was treated with naproxen and an intra-articular injection of bupivacaine hydrochloride and epinephrine. She denied any other recent or remote injury or trauma. She said her pain was worse with weight bearing or any activity, and she noted that she felt an occasional popping in her hip.

Her medical history was unremarkable except for normal childhood illnesses. She was allergic to cefaclor. Results of a review of systems were otherwise benign; she had no fever or malaise, no rashes, no joint swelling, and no lymphadenopathy. She denied any recent upper respiratory tract infections or other illnesses.

She walked with a very mildly antalgic gait, but her rotational profile was symmetrical and her legs were equal in length; she displayed no Trendelenburg sign. Her spine was normal. She had full flexion of both hips with symmetrical internal rotation of about 60 degrees in the prone position. Hip impingement testing (flexing the hip to 90 degrees and then adducting and internally rotating it) produced significant pain; however, she had minimal to no pain with abduction and with external rotation. Results of a neurovascular examination of the right lower extremity were normal.

Radiographs were obtained. A standing anteroposterior (AP) view of the pelvis and bilateral false profile (25 degrees oblique) views of the hips revealed a dysplastic hip on the right side with mild coxa magna (slightly large femoral head compared with the left side) (

). The lateral center edge angle of the right hip was neutral, and the anterior center edge measured −5 degrees. Anterior and lateral coverage of the left hip, by contrast, was more than 25 degrees (which is the norm). There was minimal subluxation, and congruency between the  femoral head and the acetabulum was maintained on radiography.

MRI of the affected hip revealed no distinct labral tear. There was no evidence of degenerative joint disease and no avascular change in the right femoral head.

The patient and her parents elected to postpone surgery until after she had completed her senior year of high school; she was instructed to return when she wanted to proceed. She returned 9 months later complaining of worsening pain.


 DEVELOPMENTAL DYSPLASIA OF THE HIP: AN OVERVIEW



DDH refers to a spectrum of abnormalities involving the growing hip, including subluxation, dislocation, and alteration of the size, shape, or organization of the femoral head and/or acetabulum. It is estimated that DDH affects between 1 and 1.5 children for every 1000 births, with some studies showing as many as 9 of every 1000 children affected.

The risk of DDH is much higher in girls, and firstborn children are affected twice as often as those later in the birth order. A child whose first-degree relative was affected by DDH has a slightly increased risk. Children with oligohydramnios, torticollis, clubfeet, or connective-tissue disorders are also at a higher risk.

 The left side is more often affected than the right side.

There is also geographical and racial variation in the incidence of DDH. An increased incidence has been noted in North America and among Native Americans; in contrast, DDH is seldom seen among African American or Chinese children.

The etiology of the disorder is multifactorial, with mechanical, hormonal, genetic, and various other mechanisms possibly playing roles. The risk of DDH is increased with intrauterine crowding or breech presentation and in neonates whose hips are held in an extended and adducted position while swaddled or wrapped. Maternal hormones can induce significant ligament laxity, which could explain the higher incidence of DDH in girls.

Early diagnosis of DDH is important to prevent the long-term effects of untreated hip dysplasia, such as those seen in this teenager. Dysplasia that has gone unnoticed during childhood can result in degenerative arthritis by the teenage or young adult years.

 The ideal time to detect DDH is in the newborn period. When the disorder is diagnosed in infancy, treatment is effective more than 90% of the time.

Developmental dysplasia of the hip (DDH) was diagnosed. It was explained to the patient and her family that a reconstructive procedure was indicated. The risks and benefits of the recommended procedure (a periacetabular osteotomy) were discussed, along with the typical preoperative and postoperative course.

Often DDH can be picked up in a neonate with a routine history taking and physical examination. Signs and symptoms that suggest the diagnosis (

) include asymmetric skin folds; the presence of a condition known to be associated with DDH, such as torticollis or clubfoot; and one knee lower than the other when the infant is in a supine position with hips and knees flexed (Galeazzi sign [



   Two maneuvers are also commonly used to detect DDH in infants. In the Ortolani maneuver, one hip is held in abduction while the other is gently manipulated to see whether the femoral head can be reduced into the acetabulum (

). In the Barlow maneuver, gentle downward pressure is applied to one hip to determine whether the femoral head can be dislocated from the acetabulum (



When a clinical abnormality is detected in an infant up to 6 to 8 months of age-or when the history or other physical findings place an infant at high risk for DDH- ultrasonography of the hip(s) is warranted. Ultrasonography is preferred to radiographs in children younger than 6 months because the femoral head has not yet ossified, and cartilage and soft tissues are better delineated on an ultrasonogram. After age 6 months, plain AP and frog-leg pelvis radiographs are usually ordered. If imaging studies reveal any abnormality, refer the child to a pediatric orthopedist for evaluation.



Intervention in infants who have not yet begun to walk is by means of a hip abduction orthosis known as a Pavlik harness. As children reach walking age, casting with open or closed reduction of the hip is required. Any residual dysplasia is treated with surgical management using various reconstructive options.

Although infancy is the ideal time to intervene to correct DDH, surgical correction is often recommended at whatever age the condition is identified; residual dysplasia is a major cause of disability. The treatment of adolescents and young adults with hip disorders such as DDH has changed significantly over the past 10 years; these changes are the result of better understanding of prearthritic and early arthritic disease and of improved diagnostic skills and surgical procedures.

Periacetabular osteotomy is quickly becoming one of the surgical interventions of choice in patients under the age of 40.

 Adults and adolescents in whom the triradiate cartilage is closed, whether or not they have had previous treatment or surgery, can benefit from a periacetabular osteotomy.

 The procedure produces a more normal configuration of the hip joint and improves load-bearing capacity; it thus arrests the degenerative process and may greatly improve hip joint longevity.

 In addition, periacetabular osteotomy leaves the posterior column intact, thereby maintaining stability in the pelvic ring- an advantage over other types of osteotomies, especially for women of childbearing age.



 The patient underwent periacetabular osteotomy. She healed uneventfully; 

, an AP radiograph of her pelvis 3 months after surgery, shows the healed osteotomy. At this point, she had very little pain. Her mobility continues to improve, and her risk for early degenerative arthritis is significantly reduced.

 Guille JT, Pizzutillo PD, MacEwen GD. Developmental dysplasia of the hip from birth to six months. 

 Haynes RJ. Developmental dysplasia of the hip: etiology, pathogenesis, and examination and physical findings in the newborn. 

 Willis RB. Developmental dysplasia of the hip: assessment and treatment before walking age. 

 Staheli LT. Surgical management of acetabulardysplasia. 

 Clohisy JC, Keeney JA, Schoenecker PL. Preliminary assessment and treatment guidelines for hip disorders in young adults. 

 Wenger DR, Bomar JD. Human hip dysplasia:evolution of current treatment concepts. 

 Brooklandville, MD: Data Trace Publishing Co; 2006:189-191.

A 17-year-old girl presented for evaluation of right hip pain. Several months earlier she had incurred a twisting injury to her hip when she landed from a jump while dancing.

Hip Pain in a Teenaged Girl

A well-nourished 17-year-old of average height and weight was referred for evaluation of persistent right lower leg pain of 3 months' duration. He was not taking any medications, had no allergies, and denied trauma to the area.

The pain was localized to the mid aspect of the right anterolateral tibia; it was exacerbated by walking and exercise and slightly alleviated with rest and ibuprofen. A subtle lump was palpable in the mid shin area laterally.

Plain radiographs of the tibia and fibula revealed marked sclerosis and cortical thickening at the mid diaphysis of the tibia; an oval lucency was detected within the posterolateral cortex, consistent with a nidus (

). A helical CT scan demonstrated cortical hyperostosis that involved the posterolateral aspect of the tibial cortex; the nidus measured 7 3 14 mm (

Osteoid osteomas account for about 10% of all benign bone tumors.

 They can arise in any bone. The typical tumor site is the cortical bone, most commonly the tibia and femur.

 The tumors develop in immature bones and thus are usually found in persons younger than 20 years. The male-to-female ratio is 2:1.

The tumor is composed of osteoblasts and an osteoid that forms a small (less than 2 cm) radiolucent nidus, which is surrounded by an increased neural and arterial supply. The pain probably results from the increase in neural cells around the nidus; it typically worsens at night and is relieved by NSAIDs or aspirin.

 The abnormal growth is likely a response to the increased arterial supply around the nidus; in some patients, this may be palpable.

Osteoid osteomas can be managed with watchful waiting and NSAIDs as needed, surgical excision and curettage, or radiofrequency (RF) ablation.

 Surgery can be painful and inaccurate identification or incomplete excision of the tumor can lead to recurrence. RF ablation is more widely used and allows for osteonecrosis without injury to the adjacent bone.

This patient and his parents chose RF ablation. Six months after treatment, he had no symptoms and the lesion had not recurred.	*

 Gebauer B, Tunn PU, Gaffke G, et al. Osteoid osteoma: experience with laser- and radiofrequency-induced ablation. 

 Cohen MD, Harrington TM, Ginsburg WW. Osteoid osteoma: 95 cases and a review of the literature. 

 Marcove RC, Heelan RT, Huvos AG, et al. Osteoid osteoma. Diagnosis, localization, and treatment. 

Pamela Horn, MS

Articles

A New Zip in Playground Injuries

Hip Pain in a Teenaged Girl

Osteoid Osteoma in a Teenager