Clinical and Radiographic Outcomes After Submuscular Plating (SMP) of Pediatric Femoral Shaft Fractures.
BACKGROUND
To evaluate lower extremity strength and alignment among children who underwent submuscular plating (SMP).


METHODS
Subjects who underwent SMP for a length unstable femoral fracture returned for isokinetic strength testing ≥2 years after surgery. Extensor and flexor strength deficits (percent difference) between the operative and nonoperative limbs were evaluated. Radiographic measurements of mechanical alignment [anatomic lateral distal femoral angle (aLDFA)] and qualitative measurements (The Pediatric Outcomes Data Collection Instrument, PODCI) were obtained from all subjects. The upper 97.5% confidence interval approach to establishing clinical equivalency was utilized to compare differences in strength and alignment between the operative and nonoperative limbs. An extensor strength deficit of >19% and an aLDFA discrepancy of >5 degrees were considered to be clinically significant.


RESULTS
The average age at surgery of the 10 subjects included in the study was 8.7 years. The hardware was placed an average of 27.9 mm from the distal femoral physis and was removed 6.4 months postsurgery. Among all subjects, the median PODCI scores were ≥97 according to all subscales. There was no significant difference in extension torque between the operative versus nonoperative limbs at 60 degrees/s (P=0.5400), 120 degrees/s (P=0.4214), or 180 degrees/s (P=0.8166). More importantly, extension strength deficits between the operative and nonoperative limbs were not clinically significant at 60 degrees/s [upper 97.5% confidence interval (CI), 10.9%], 120 degrees/s (upper 97.5% CI, 11.0%), or 180 degrees/s (upper 97.5% CI, 10.7%). The difference in aLDFA between the operative and nonoperative limb was less than the predefined clinically significant threshold of 5 degrees for all subjects.


CONCLUSIONS
SMP achieves satisfactory clinical and functional results. In this series, extensor strength deficits and/or lower extremity malalignment were not clinically meaningful. High patient satisfaction can be expected after implant removal.


METHODS
Level IV-case series.
Department of Pediatric Orthopaedic Surgery, Musculoskeletal Research Center.
Jason W
JW
Stoneback
Department of Pediatric Orthopaedic Surgery, Musculoskeletal Research Center.
Patrick M
PM
Carry
Department of Pediatric Orthopaedic Surgery, Musculoskeletal Research Center.
Katherine
K
Flynn
Department of Pediatric Orthopaedic Surgery, Musculoskeletal Research Center.|Department of Pediatrics, Research Institute, The Children's Hospital Colorado, Aurora, CO.
Zhaoxing
Z
Pan
Department of Orthopaedic Surgery, Center for Hip Preservation, Hospital for Special Surgery, New York, NY.
Ernest L
EL
Sink
Department of Pediatric Orthopaedic Surgery, Musculoskeletal Research Center.
Nancy H
NH
Miller
D001860:Bone Plates; D002648:Child; D020878:Device Removal; D005260:Female; D005264:Femoral Fractures / Q000000981:diagnostic imaging* / Q000601:surgery*; D005593:Fracture Fixation, Internal / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D008297:Male; D017060:Patient Satisfaction; D011859:Radiography; D019415:Torque; D016896:Treatment Outcome