External fixation of pediatric femur fractures

One-hundred and thirty-two children with 139 femur fractures were treated with external fixation from 1984 to 1993. Average age at presentation was 8.97 years. All fractures were followed until union, with an average time of external fixation of 11.4 weeks. There were no nonunions. Of 18 patients with definitive radiographic measurements at 2-year follow-up, 15 patients developed overgrowth (average, 8.7 mm) and three demonstrated shortening (average, 7.7 mm). No patient required treatment for residual leg-length discrepancy. Although pin-tract inflammation was common, pin-tract infection requiring intravenous antibiotics occurred in only six patients (4.5%). No patient developed osteomyelitis. Two fractures (1.4%) were not healed at the time of elective fixator removal, necessitating additional time in the fixator. There were two refractures (1.4%) and one fracture through a healing pin tract after fixator removal (0.7%).

The torsional basis for slipped capital femoral epiphysis

Fifteen moderate to severe acute slipped capital femoral epiphyses were manipulated in 15 patients to correct significant deformities; in each case, torsion played a critical role in the reduction. Nine of 15 patients with acute slips underwent controlled, open reduction from the anterolateral approach, stabilizing the epiphysis while the metaphysis was internally rotated, flexed, and abducted; none had osteonecrosis or chondrolysis. The other 6 acute slips were treated with traction using internal rotation to achieve closed reduction; 2 of these 6 closed reductions progressed to osteonecrosis, and both were reduced in an uncontrolled situation. Of the 15 acute slips, 6 involved torsion as the primary force. Based on the importance of torsion in all the reductions and the prevalence of torsion as an etiologic factor in the initial slips, it is postulated that torsion is an important contributing component in the etiology of slipped capital femoral epiphysis. Despite 2 cases of osteonecrosis in unstable hips, these 15 manipulative reductions were 87% successful. If the 2 inadvertent closed reductions are eliminated, then the success rate is 100%.

External fixation of femur fractures in children

Forty-two children (44 femur fractures) were treated by primary external fixation and early weightbearing (1984-1989). The fractures were reduced anatomically when possible. Average age at fracture was 9 years 7 months (range, 2 years 5 months to 17 years 8 months). Duration of external fixation averaged 70 days (range 42-117 days). Of 176 pins, 15 (8.5%) were inflamed and five (2.8%) required intravenous antibiotics; none resulted in osteomyelitis. Most patients returned to school by 4 weeks, and all had full knee motion 6 weeks after fixator removal. Of 16 patients with documented follow-up of at least 18 months, only six (38%) had overgrowth from 2 to 10 mm (average 5.8 mm).

Efficiency of the bone scan for occult limping toddlers

Fifty consecutive occult limping toddlers were prospectively evaluated by acute triphase 99mTc MDP scintigraphy (TTS) at Arkansas Children's Hospital from 1984 through 1989. Only patients with a limp that could not be diagnosed by an orthopaedist were included. TTS proved essential in localizing the lesion in 27 patients (54%). With only two false negatives and one false positive, this test was shown to be highly sensitive, specific, efficient, and predictive, especially as compared with temperature, white blood cell (WBC) count, erythrocyte sedimentation rate (ESR), and plain radiography. Because no infections were missed by TTS, patients with a normal TTS could be safely observed as outpatients, saving thousands of health care dollars in this small series.

Muscle training: physiology and practical applications of training for strength versus endurance

An understanding of the physiology of muscle training can help the athlete, trainer, or therapist make specific improvements in athletic performance. Different metabolic pathways of muscle contraction predominate depending upon the type of work performed. Two anaerobic pathways provide energy for fast, powerful contractions while aerobic metabolism fuels sustained muscular endurance activities. Two types of human muscle fibers have been identified. Selective training of the different muscle fiber types can enhance performance in a particular sport.