Merv Letts

Fracture of the pars interarticularis in adolescent athletes: a clinical-biomechanical analysis.

Stress fracture of the pars interarticularis is an increasing cause of disability in highly competitive adolescent athletes. We have documented this lesion in 14 adolescent athletes engaged in repetitive training and competition exercises involving flexion/extension of the lumbar spine. An in vivo spinal muscle torque study in 11 normal adolescent girls also revealed mean torque values of 22.6 Nm for left lateral flexion and 27.4 Nm for hyperextension. The most common sports resulting in this lesion were gymnastics and hockey. In four patients the lesion was bilateral, and in 10 it was unilateral. Five of the unilateral lesions went on to heal with immobilization in a thoracolumbar spinal orthoses; however, none of the four bilateral lesions or the remaining five unilateral lesions healed in spite of 3 months of immobilization.

Effects of a tensioned tendon graft in a bone tunnel across the rabbit physis.

Children who sustain anterior cruciate disruption often are denied the standard reconstructive procedures because of the concern that drilling across the physis of the tibia and femur and compression from a tensioned graft will result in growth plate arrest. To test this concept and to assess whether a tendon placed in the tunnel would function in a manner similar to a fat graft after the resection of a physeal bar, tunnels were made across the proximal tibial physis and distal femoral physis in a group of immature rabbits. Four tunnel diameters were used from 1.95 to 3.97 mm, in three rabbits at each diameter, with patellar tendon autografts being used as the reconstruction of the anterior cruciate ligament in two of the animals. The knees were radiographed every 4 weeks, and the animals were euthanized 4 months after surgery. The surgically treated and control knees were salvaged, and each knee was examined grossly, radiographically, and histologically. Eight of the 11 animals had growth arrest of one or both physes. The larger the drill hole diameter the more marked was the deformity. The proximal tibial physis seemed to be the most vulnerable for growth arrest, occurring in eight of the knees. The insertion of a tendon did not seem to offer any protection to physeal arrest. Because of these findings, it is not recommended that tunnels involving 1% or more of the area of the physis be placed across the tibial and femoral physis to reconstruct the anterior cruciate in very skeletally immature children.

Long-term effects of neonatal bone and joint infection on adjacent growth plates.

Review of children with physeal damage from neonatal infection other than the hip at Winnipeg Childrens Hospital showed that six patients had residual growth interference from adjacent infection in the bone or joint. Several of the infections involved multiple joints, with growth plate arrest occurring in the distal femoral growth plate in four, in the proximal humerus in four, in the proximal femur in two, in the distal radius in one, and in the distal humerus in one. Although the initial infection was frequently believed to be successfully treated in the neonate, the clinical effect of these infections on the growth plate was not fully appreciated in five of the infants until the children reached a mean age of 9 years. Because growth abnormalities in physeal bars may not be clinically evident for several years after the initial infection has been treated, we recommend that children with bone and joint infections occurring in the first month of life be followed to skeletal maturity, observing the adjacent physis for late tethering.

Complications of rigid intramedullary rodding of femoral shaft fractures in children

BACKGROUND Intramedullary rodding of femoral shaft fractures has been frequently performed in adults, but until recently rarely in children. It was the purpose of this study to investigate the experience with this treatment method at a pediatric trauma center. METHODS From 1987 to 1998, 54 children were treated for traumatic femoral fractures with intramedullary rods at a major pediatric trauma center. The average age was 15 years 3 months, ranging between 11 years 4 months and 17 years 11 months. The average follow-up was 5 years 3 months, ranging from 20 months to 10 years 1 month. RESULTS All of the fractures occurred secondary to trauma and the most common anatomic fracture site was the femoral midshaft. Complications encountered included 8 instances of minor limb length discrepancy, 11 instances of discomfort because of rod prominence, 1 case of avascular necrosis of the femoral head, 2 instances of heterotopic ossification over the rod tip, 1 broken rod, and 3 cases that demonstrated decreased external rotation of the affected limb. One child developed osteomyelitis after intramedullary rodding for a fracture previously treated with external fixation. There were no cases of surgically induced nonunion or malunion and only one delayed union secondary to infection. CONCLUSION Results of this series demonstrate intramedullary rodding to be an effective treatment modality for femoral fractures in skeletally mature children. In children with open femoral physes, rigid rodding should be avoided because of the small but serious occurrence of avascular necrosis of the femoral head. Intramedullary rodding is not recommended in children initially treated with external fixation because of the increased risk of infection.

A biomechanical analysis of halo fixation in children

The use of prolonged halo stabilisation in a child is increasingly indicated for trauma and congenital instability of the cervical spine, but complications of pin fixation in this age group are frequent. We have analysed four aspects of the mechanics of the halo pin: the forces applied by each of six surgeons was shown to vary widely, penetration of the inner table occurred relatively easily, friction at the pin-halo interface influenced forces, and the skull thickness measured by CT scan varied from 1.1 mm to 4.3 mm in children under six years of age. We recommend CT scanning of the skull before elective halo application in young children to ascertain the safest pin sites.

Unicameral bone cyst of the calcaneus in children.

The calcaneus is an uncommon site for a unicameral bone cyst. However, because of the concentration of forces through the heel, such cysts are usually symptomatic and require treatment. Because of the lack of attention paid to calcaneal unicameral bone cysts, as well as the controversy concerning their appropriate treatment and ultimate outcome, a retrospective study of our experience was undertaken. Over a 15-year period, we treated six children with calcaneal unicameral bone cysts. The diagnosis was confirmed pathologically at the time of treatment for all six. The most common presenting complaint was heel pain upon weight-bearing, secondary to microfracturing of the cyst. Although conservative treatment, which entailed casting and sponge fillers in the shoes, was attempted for most patients, none responded to this form of management. One child had three separate injections of methylprednisolone acetate without any radiographic or clinical change in the cyst, which ultimately required curettage and bone grafting. Bone grafting with either autogenous or allograft bone was successful in eradicating the cyst in all six patients, with no symptoms of recurrence at an average follow-up of 4 years. No resultant treatment complications were encountered. Unicameral bone cysts of the calcaneus, when symptomatic, respond well to curettage and bone grafting, and this type of treatment is recommended.

Osteochondritis dissecans of the talus in children

Osteochondritis dissecans (OCD) of the talus is rare in children. The lesion is encountered on either the medial or lateral surface of the talar dome. The etiology is unknown, although trauma has been implicated, particularly in lateral lesions. Since 1983, 24 children have been treated for OCD of the talus at a major Canadian pediatric referral center. Two children had bilateral involvement, for a total of 26 lesions. There were 10 boys and 14 girls. The average age at initial presentation was 13 years 4 months (range 6 years 7 months to 17 years 1 month). The lesion involved the medial aspect of the talus in 19, the lateral in 5, and the central talar dome in 3. Magnetic resonance imaging was very useful in preoperative assessment in six cases. Surgical intervention was required in 15 (58%) ankles. The results at the most recent follow-up revealed resolution or decreased symptoms in 25 (96%) and no change in 1 (4%).

Fractures of the capitellum in adolescents.

Fractures of the capitellum are rare in children. The treatment of these injuries has been controversial. At a major pediatric trauma center, seven capitellar fractures were seen in children between 1988 and 1994. The average age of the children was 14.7 years (range, 11-17). Six of these fractures were type I injuries, with large anterosuperior fragments that required operative reduction and internal fixation in five cases. Internal fixation methods used were K wires in three patients, Herbert screws in one patient, and cannulated screws in one patient. The remaining type I fracture was treated with a closed reduction. The seventh fracture was a type II fracture, treated nonoperatively. Five children did well with their respective treatments, but one required reoperation to remove an exostosis block to flexion. Accurate open reduction and internal fixation for the displaced capitellar fracture in children is an effective treatment to restore normal elbow function.

Pelvic osteomyelitis in children: a comparison of decades from 1980-1989 with 1990-2001.

Since 1980, 64 children with pelvic osteomyelitis (40 boys) were treated at a major pediatric referral center. The average age was 11 years and 6 months. The presenting complaints included pain in 61 children, fever in 30, and altered weight-bearing in 31. The erythrocyte sedimentation rate was elevated in 56 and there was leukocytosis in 19. The most commonly affected sites were the ilium in 21 and the acetabulum in 20, followed by the pubis in 11 and the ischium in 10. Culture results were negative in 32 and positive for Staphylococcus aureus in 26. Treatment consisted of intravenous antibiotics in 62 and irrigation and debridement in five children, all of whom presented since 1990. The infection resolved in 62 children and persisted in two. Three developed complications, including fusion of the sacroiliac joint in one, deformity of the acetabulum in one, and one child with an underlying protein C deficiency developed thromboembolism. Recent patients have demonstrated increased severity, likely due to increased virulence of the organism.

Management of scoliosis and syringomyelia in children

Scoliosis is often a characteristic of an underlying syrinx. Surgical treatment, in particular instrumentation, of scoliosis in a child with an unrecognized syrinx may be associated with an increased risk of neurologic complications. The effect of syrinx treatment on scoliosis is yet to be clearly determined. Since 1976, nine children with scoliosis and a syrinx have been treated at a major pediatric referral center. Follow-up averaged 4 years 9 months. The average increase in curve size was 12° (range 2°–43°). The syrinx was treated operatively in five children. One child, who underwent foramen magnum decompression, required surgical stabilization of the spine. No neurologic complications were encountered. A compilation of reported cases in the literature was performed and analyzed. This analysis of 98 cases revealed that treatment of the syrinx resulted in no further progression of the scoliosis in 35 of 80 (48%) cases in which the curve history was reported. Surgical stabilization of the curve was required in 27 (31%) cases without neurologic complications.