Proximal Femoral Deformity Following Threaded Prophylactic Fixation for Slipped Capital Femoral Epiphysis: Risk Stratification Using the Modified Oxford Score.

BACKGROUND: This study assesses the effect of skeletal maturity on the development of iatrogenic proximal femoral deformity following threaded prophylactic screw fixation in patients presenting with unilateral slipped capital femoral epiphysis (SCFE). METHODS: Children who underwent threaded screw prophylaxis of the uninvolved hip (Group P) and those who were observed with no prophylaxis (Group N) on presentation with unilateral SCFE were compared. Skeletal maturity was assessed with the Modified Oxford Score (MOS). Proximal femoral morphology was characterized by femoral neck length, femoral neck width, neck shaft angle, and trochanteric femoral head overlap percentage (TFHOP). Femoral head deformity at final follow-up was characterized as spherical (Type 1), mildly aspherical (Type 2), or ovoid (Type 3). Analysis of variance and t test were used to compare the groups. RESULTS: Thirty-eight patients in Group P and 17 patients in Group N met inclusion criteria. The average follow-up was 2.6 years. Group P was younger than Group N by an average of 9.6 months (P=0.04), but the MOS for skeletal maturity was not different between groups (P=0.15). Group P had significantly diminished neck length (P=0.008) and significantly increased relative trochanteric overgrowth as evidenced by increased trochanteric femoral head overlap percentage (P<0.001), but there was no difference between groups in neck shaft angle and neck width. No patient in Group N developed femoral head deformity (all Type 1). In Group P, 14 patients (37%) developed Types 2 and 3 deformity. In patients with MOS 16 in Group P, 60% (3/5) developed Type 2 deformity and 40% (2/5) developed Type 3 deformity. In patients with MOS 17 in Group P, 45% (5/11) had Type 2 deformity. CONCLUSIONS: Skeletally immature patients with an MOS of 16 and 17 are at high risk for developing the triad of relative trochanteric overgrowth, coxa breva, and femoral head asphericity with prophylactic threaded screw fixation for SCFE. When prophylactic surgery is indicated, consideration should be given to growth friendly fixation strategies to avoid iatrogenic proximal femoral deformity. LEVELS OF EVIDENCE: Level III-therapeutic retrospective comparative study.

Quantitative Assessment of Muscle Strength Following "Slow" Surgical Lengthening of the Medial Hamstring Muscles in Children With Cerebral Palsy.

BACKGROUND: Classic teaching for surgical lengthening of muscle contractures in children with cerebral palsy (CP) has emphasized complete correction of the deformity acutely, with immobilization of the targeted muscles in the fully corrected position. Clinical experience has led to the impression that the muscles are invariably weakened by this approach. We have developed an alternative technique for correction of contractures called slow surgical lengthening (SSL). The goal of the study was to determine the physical examination, kinematic, and muscle strength outcomes following SSL of the medial hamstring muscles in children with CP. METHODS: The study group included 41 children with CP who underwent SSL of the medial hamstring muscles as part of a comprehensive single-event multilevel surgery, who had preoperative and 1-year postoperative evaluations in our Motion Analysis Center, which included quantitative assessment of isometric and isokinetic muscle strength. RESULTS: All subjects were Gross Motor Function Classification System I and II. Mean age at the time of surgery was 10.8 years. The mean popliteal angle improved by 16.2 degrees (P<0.001) following SSL of the medial hamstrings. Sagittal plane kinematics following SSL of the medial hamstrings showed improvement of knee extension at initial contact of 10.2 degrees (P<0.001), decrease of peak knee flexion in mid-swing of 3.6 degrees (P=0.014), improved minimum knee flexion in stance of 4.9 degrees (P=0.002), and no significant change in mean anterior pelvic tilt (P=0.123). Mean peak isometric knee flexion torque remained unchanged from preoperative to postoperative studies (P=0.154), whereas mean peak isokinetic knee flexion torque significantly increased by 0.076 Nm/kg (P=0.014) following medial hamstring SSL. DISCUSSION: SSL was developed based upon clinical experience and improved understanding of the pathophysiology of skeletal muscle in children with CP. The SSL technique allows the tendinous tissue to separate spontaneously at the time of recession, but does not force further acute lengthening by intraoperative manipulation, thereby minimizing the damage to the underlying muscle. It is broadly believed that muscle weakness is inevitable following surgical lengthening. The current study shows that the SSL technique does not cause weakness. LEVEL OF EVIDENCE: Level IV-therapeutic.

Symphysis pubis width in the pediatric population: A computerized tomography study.

BACKGROUND: Defining pathologic widening of the pubic symphysis in the pediatric population continues to be a clinical challenge. The purpose of this study is to define a normal range of pubic symphyseal widths in various age and gender groups using axial computerized tomography (CT) scans. METHODS: Axial CT images of 140 patients aged between 2 years and 15 years were obtained from our database of preexisting scans. Using a commercially available software package, the single image with the narrowest pubic symphyseal width was identified and measured. Patients were further stratified based on gender and by age into three groups: group A (age 2-5 years), group B (age 6-11 years), and group C (age 12-15 years). RESULTS: The mean width ± 95% confidence interval for all cases was 4.59 mm ± 0.18 mm. The mean width for male and female patients was 4.86 mm ± 0.26 mm and 4.33 mm ± 0.24 mm, respectively. Based on the two-way analysis of variance, both age group and gender had a statistically significant effect. Post hoc testing demonstrated a statistically significant difference in mean symphyseal width between groups A and C (p < 0.0001) and groups B and C (p = 0.0025) but not between groups A and B (p = 0.055). When grouped by age, the mean male pubic symphyseal width was found to be 5.10 mm, 4.93 mm, and 4.45 mm, while the mean female width was found to be 4.94 mm, 4.33 mm, and 3.54 mm at 2 to 6 years, 7 to 11 years, and 12 to 15 years of age, respectively. CONCLUSION: In the pediatric population, males seem to have a wider pubic symphysis than females of the same age group. In both males and females, pubic symphyseal width decreases during the transition from infancy toward skeletal maturity. LEVEL OF EVIDENCE: Epidemiologic study, level III.

Adult outcomes following amputation or lengthening for fibular deficiency.

BACKGROUND: Fibular deficiency results in a small, unstable foot and ankle as well as a limb-length discrepancy. The purpose of this study was to assess outcomes in adults who, as children, had had amputation or limb-lengthening, commonly used treatments for fibular deficiency. METHODS: Retrospective review of existing data collected since 1950 at six pediatric orthopaedic centers identified 248 patients with fibular deficiency who were twenty-one years of age or older at the time of the review. Excluding patients with other anomalies and other treatments (with the excluded group including six who had had lengthening and then amputation), we identified ninety-eight patients who had had amputation or limb-lengthening for the treatment of isolated unilateral fibular deficiency. Sixty-two patients (with thirty-six amputations and twenty-six lengthening procedures) completed several questionnaires, including one asking general demographic questions, the Beck Depression Inventory-II, the Quality of Life Questionnaire, and the American Academy of Orthopaedic Surgeons Lower Limb Questionnaire including the Short Form-36. A group of twenty-eight control subjects completed the Beck Depression Inventory-II and the Quality of Life Questionnaire. RESULTS: There were forty men and twenty-two women. The average age at the time of the interview was thirty-three years. There were more amputations in those with fewer rays and less fibular preservation. Lengthening resulted in more surgical procedures (6.3 compared with 2.4 in patients treated with amputation) and more days in the hospital (184 compared with sixty-three) (both p<0.0001). However, when we compared treatment outcomes we did not find differences between groups with regard to education, employment, income, public assistance or disability payments, pain or use of pain medicine, sports participation, activity restriction, comfort wearing shorts, dislike of limb appearance, or satisfaction with treatment. No patient who had been treated for fibular deficiency reported signs of depression. The only significant difference between treatment groups shown by the Quality of Life Questionnaire was in the scores on the Job Satisfiers content scale, with the amputees scoring better than the patients treated with lengthening (p=0.015). The American Academy of Orthopaedic Surgeons Lower Limb Module did not demonstrate differences in health-related quality of life or physical function. CONCLUSIONS: The patients who were treated with lengthening had started out with more residual foot rays and more fibular preservation than the amputees. They also required more surgical intervention than did those with an amputation. While patients with an amputation spent less of their childhood undergoing treatment, they were found to have a better outcome in terms of only one of seventeen quality-of-life parameters. Both groups of patients who had had treatment of fibular deficiency were functioning at high levels, with an average to above-average quality of life compared with that of the normal adult population.

Muscle adaptation by serial sarcomere addition 1 year after femoral lengthening.

A common complication of reconstructive surgery is muscle contracture and consequent loss of joint motion. This particularly occurs in surgical lengthening procedures where the muscle adaptive capacity seems to limit the extent of possible lengthening. We used intraoperative laser diffraction to determine the skeletal muscle adaptation that occurred in a 16-year-old girl who had 4-cm femoral lengthening for a leg-length discrepancy secondary to posttraumatic growth arrest. Fascicle length changed dramatically during distraction from a starting value of approximately 9 cm to a new length of 19 cm. In vivo vastus lateralis sarcomere length measured intraoperatively at the initial surgery was 3.64 microm, whereas sarcomere length measured 8 months later was 3.11 microm. The fact that fascicle length increased dramatically and in vivo sarcomere length decreased slightly reveals an increase in serial sarcomeres from 25,000 to 58,650. This direct measurement of fascicle length and sarcomere length confirms sarcomerogenesis in human skeletal muscle secondary to chronic length change, and shows the capacity of human muscle to adapt to length changes.

Reliability of radiographic parameters in neuromuscular scoliosis.

STUDY DESIGN: Retrospective review of radiographic data. OBJECTIVES: This study sought to define interobserver and intraobserver variability to further delineate reliable means by which radiographs of patients with neuromuscular scoliosis can be examined. SUMMARY OF BACKGROUND DATA: Previous studies analyzed the use of Cobb angles in the measurement of idiopathic and congenital scoliosis, but no study until now describes a critical analysis of measurement in evaluating neuromuscular scoliosis. METHODS: Forty-eight patients with neuromuscular scoliosis radiographs were reviewed. These were evaluated for Cobb angle, end vertebrae selection, Ferguson angle, apex of the curve, C7 balance, pelvic obliquity, Risser sign, status of the triradiate cartilage, kyphosis Cobb angle, endplate selection for kyphosis, and kyphotic index. Interclass and intraclass variability was examined with statistical analysis. RESULTS: Cobb angle had an intraobserver variability was 5.7 degrees and the interobserver variability was 14.8 degrees . The intraobserver and interobserver variability for Ferguson angle was 6.8 degrees and 20.6 degrees, respectively. The kyphotic Cobb angle intraobserver variability was found to be 17.4 degrees, and the interobserver variability was 24.01 degrees . CONCLUSIONS: Neuromuscular scoliosis radiographs can be reliably analyzed with the use of Cobb angle. Other forms of analysis, such as Ferguson angle, are not as reliable. Pelvic obliquity should be measured from the horizontal, as other methods are not as reliable. Kyphosis is best evaluated with the use of the kyphotic Cobb angle. Finally, it is felt that a separate anteroposterior pelvis radiograph should be used to assess skeletal maturity, as scoliosis films often truncate the vital anatomy necessary to determine skeletal maturity.