A Biomechanical Comparison Of Pin Configurations Used For Percutaneous Pinning Of Distal Tibia Fractures In Children.

BACKGROUND: Percutaneous pin fixation is often used in conjunction with closed-reduction and cast immobilization to treat pediatric distal tibia fractures. The goal of this procedure is to maintain reduction and provide improved stabilization, in effort to facilitate a more anatomic union. We conducted a biomechanical study of the torsional and bending stability of three commonly used pin configurations in distal tibia fracture fixation. METHODS: A transverse fracture was simulated at the metaphyseal/diaphyseal junction in 15 synthetic tibias. Each fracture was reduced and fixed with two Kirschner wires, arranged in one of three pin configurations: parallel, retrograde, medial to lateral pins entering at the medial malleolus distal to the fracture (group A); parallel, antegrade, medial to lateral pins entering at the medial diaphysis proximal to the fracture (group B); or a cross-pin configuration with one retrograde, medial to lateral pin entering the medial malleolus distal to the fracture and the second an antegrade, medial to lateral pin entering at the medial diaphysis proximal to the fracture (group C). Stability of each construct was assessed by resistance to torsion and bending. RESULTS: Resistance to external rotation stress was significantly higher in group A than group B (P = 0.044). Resistance to internal rotation stress was significantly higher in group C than group B (P = 0.003). There was no significant difference in torsional stiffness when comparing group A with group C. Under a medial-directed load, group B and C specimens were significantly stiffer than those in group A (28 N/mm and 24 N/mm vs. 14 N/mm for A; P = 0.001 and P = 0.009, respectively). CONCLUSIONS: None of the three pin configurations produced superior results with respect to all variables studied. Group A configuration provided the highest resistance to external rotation forces, which is the most clinically relevant variable under short-cast immobilization. Parallel, retrograde, medial to lateral pins entering at the medial malleolus provide the greatest resistance to external rotation of the foot while minimizing the potential for iatrogenic injury to soft tissue structures.

A Modification to the McHale Procedure Reduces Operative Time and Blood Loss.

BACKGROUND: Treatment of symptomatic spastic hip dislocations in adolescent patients with cerebral palsy includes a variety of described salvage type procedures. In 1990, McHale and colleagues described a technique involving a femoral head resection, valgus-producing proximal femoral osteotomy, and advancement of the lesser trochanter into the acetabulum. We have modified this technique in 3 ways by: performing it in the lateral position with a more posterior approach, not advancing the lesser trochanter into the acetabulum, and closing the capsule over the acetabulum. The purpose of this paper is to describe our technique and to compare the results to Castle type procedures and McHale procedures performed as originally described. METHODS: We retrospectively reviewed all salvage type procedures performed at our institution for spastic hip dislocations in children with cerebral palsy from 2003 to 2013. Preoperative and postoperative pain, estimated blood loss, operative time, length of stay in the hospital, and postoperative pelvis radiographs were reviewed for heterotopic ossification formation and proximal femoral migration. RESULTS: Twenty-six patients with 30 hip procedures were reviewed. The modified McHale technique had shorter operative times when compared with the supine McHale technique and the Castle procedure (134, 171, and 139 min, respectively). There was a trend toward less blood loss in the modified McHale technique, but this was not significant. There was no difference in length of stay in the hospital. The majority of McHale patients (>63%) had pain relief postoperatively, where half of the Castle patients required a revision surgery for pain (4 of 8). There was less heterotopic ossification seen in the modified McHale technique (6.25%) when compared with supine McHale and Castle techniques (both 50%). However, there was more proximal femoral migration in the modified McHale group. CONCLUSIONS: The modified McHale technique is faster with otherwise equivocal results in the immediate operative periods. There is less heterotopic bone formation but more proximal femoral migration with this new technique. LEVEL OF EVIDENCE: Level IV-case series.

Prevalence of scoliosis in patients with Fontan circulation.

OBJECTIVE: To examine the prevalence of scoliosis in patients with Fontan circulation. DESIGN: Retrospective cohort (case-only), level IV study. SETTING: A comprehensive paediatric centre. METHODS: We examined the radiographs of 194 patients who underwent Fontan completion surgery between 1998 and 2011 at a median age of 1.3 years. MAIN OUTCOME MEASURE: We collected data on the age at the last available radiograph and when scoliosis was diagnosed; we used the first available radiograph with scoliosis. We also measured the magnitude and direction of the spinal curve in patients with scoliosis. RESULTS: Median age at radiography was 3.4 years. Nineteen patients (9.8%) developed scoliosis; none of them underwent thoracotomy. Most of the patients with scoliosis were older than 5 years of age at scoliosis diagnosis and the female to male ratio was 5 : 3. The major curve was right thoracic in 12 patients (63.2%), left thoracic in four patients (21.1%) and high thoracic in three patients (15.8%). For every 1 year increase in age there was a 27% increased risk of developing scoliosis. CONCLUSIONS: There was a high prevalence of scoliosis in patients with Fontan circulation. We recommend interdisciplinary monitoring of these patients to diagnose spinal curve deformities in a timely manner.