title: Soft-Tissue Abnormalities Associated with Treatment-Resistant and Treatment-Responsive Clubfoot: Findings of MRI Analysis.
abstract: BACKGROUND
  Clubfoot treatment commonly fails and often results in impaired quality of life. An understanding of the soft-tissue abnormalities associated with both treatment-responsive and treatment-resistant clubfoot is important to improving the diagnosis of clubfoot, the prognosis for patients, and treatment.
  
  
  METHODS
  Twenty patients with clubfoot treated with the Ponseti method were recruited for magnetic resonance imaging (MRI) of their lower extremities. Among these were seven patients (six unilateral cases) with treatment-responsive clubfoot and thirteen patients (five unilateral cases) with treatment-resistant clubfoot. Demographic information and physical examination findings were recorded. A descriptive analysis of the soft-tissue abnormalities was performed for both patient cohorts. For the patients with unilateral clubfoot, we calculated the percentage difference in cross-sectional area between the affected limb and the unaffected limb in terms of muscle, subcutaneous fat, intracompartment fat, and total area. With use of the Wilcoxon signed-rank test, we compared inter-leg differences in cross-sectional areas and the intracompartment adiposity index (IAI) between treatment-responsive and treatment-resistant groups. The IAI characterizes the cross-sectional area of fat within a muscle compartment.
  
  
  RESULTS
  Extensive soft-tissue abnormalities were more present in patients with treatment-resistant clubfoot than in patients with treatment-responsive clubfoot. Treatment-resistant clubfoot abnormalities included excess epimysial fat and intramuscular fat replacement as well as unique patterns of hypoplasia in specific muscle groups that were present within a subset of patients. Among the unilateral cases, treatment-resistant clubfoot was associated with a significantly greater difference in muscle area between the affected and unaffected limb (-47.8%) compared with treatment-responsive clubfoot (-26.6%) (p = 0.02), a significantly greater difference in intracompartment fat area between the affected and unaffected limb (402.6%) compared with treatment-responsive clubfoot (9%) (p = 0.01), and a corresponding higher inter-leg IAI ratio (8.7) compared with treatment-responsive clubfoot (1.5) (p = 0.01).
  
  
  CONCLUSIONS
  MRI demonstrated a range of soft-tissue abnormalities in patients, including unique patterns of specific muscle-compartment aplasia/hypoplasia that were present in patients with treatment-resistant clubfoot and not present in patients with treatment-responsive clubfoot. Correlations between MRI, physical examination, and treatment responsiveness may aid in the development of a prognostic classification system for clubfoot.
  
  
  METHODS
  Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.
authors.affiliation: Departments of Orthopaedic Surgery (D.K.M., C.A.G., H.A., and M.B.D.), Pediatrics (C.A.G.), Neurology (C.A.G.), and Radiology (M.J.S. and P.K.C.), Washington University School of Medicine, 1 Children's Place, Suite 4S-60, St. Louis, MO 62110. E-mail address for M.B. Dobbs: dobbsm@wudosis.wustl.edu.
authors.forename: Daniel K
authors.initials: DK
authors.lastname: Moon
authors.affiliation: Departments of Orthopaedic Surgery (D.K.M., C.A.G., H.A., and M.B.D.), Pediatrics (C.A.G.), Neurology (C.A.G.), and Radiology (M.J.S. and P.K.C.), Washington University School of Medicine, 1 Children's Place, Suite 4S-60, St. Louis, MO 62110. E-mail address for M.B. Dobbs: dobbsm@wudosis.wustl.edu.
authors.forename: Christina A
authors.initials: CA
authors.lastname: Gurnett
authors.affiliation: Departments of Orthopaedic Surgery (D.K.M., C.A.G., H.A., and M.B.D.), Pediatrics (C.A.G.), Neurology (C.A.G.), and Radiology (M.J.S. and P.K.C.), Washington University School of Medicine, 1 Children's Place, Suite 4S-60, St. Louis, MO 62110. E-mail address for M.B. Dobbs: dobbsm@wudosis.wustl.edu.
authors.forename: Hyuliya
authors.initials: H
authors.lastname: Aferol
authors.affiliation: Departments of Orthopaedic Surgery (D.K.M., C.A.G., H.A., and M.B.D.), Pediatrics (C.A.G.), Neurology (C.A.G.), and Radiology (M.J.S. and P.K.C.), Washington University School of Medicine, 1 Children's Place, Suite 4S-60, St. Louis, MO 62110. E-mail address for M.B. Dobbs: dobbsm@wudosis.wustl.edu.
authors.forename: Marilyn J
authors.initials: MJ
authors.lastname: Siegel
authors.affiliation: Departments of Orthopaedic Surgery (D.K.M., C.A.G., H.A., and M.B.D.), Pediatrics (C.A.G.), Neurology (C.A.G.), and Radiology (M.J.S. and P.K.C.), Washington University School of Medicine, 1 Children's Place, Suite 4S-60, St. Louis, MO 62110. E-mail address for M.B. Dobbs: dobbsm@wudosis.wustl.edu.
authors.forename: Paul K
authors.initials: PK
authors.lastname: Commean
authors.affiliation: Departments of Orthopaedic Surgery (D.K.M., C.A.G., H.A., and M.B.D.), Pediatrics (C.A.G.), Neurology (C.A.G.), and Radiology (M.J.S. and P.K.C.), Washington University School of Medicine, 1 Children's Place, Suite 4S-60, St. Louis, MO 62110. E-mail address for M.B. Dobbs: dobbsm@wudosis.wustl.edu.
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Dobbs
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D003025:Clubfoot / Q000000981:diagnostic imaging* / Q000628:therapy*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D016896:Treatment Outcome; D055815:Young Adult
references.citation: J Pediatr Orthop B. 2005 Jul;14(4):280-4
references.pmid: 15931033
references.citation: J Bone Joint Surg Am. 2009 Jun;91(6):1350-9
references.pmid: 19487512
references.citation: Clin Orthop Relat Res. 2009 May;467(5):1294-7
references.pmid: 19184263
references.citation: Clin Orthop Relat Res. 2009 May;467(5):1238-42
references.pmid: 19130157
references.citation: J Bone Joint Surg Am. 2006 May;88(5):986-96
references.pmid: 16651573
references.citation: J Bone Joint Surg Am. 1995 Oct;77(10):1477-89
references.pmid: 7593056
references.citation: J Magn Reson Imaging. 2011 Dec;34(6):1285-94
references.pmid: 21964677
references.citation: Clin Orthop Relat Res. 1974 Jun;(101):229-31
references.pmid: 4837936
references.citation: J Pediatr Orthop B. 1995;4(2):129-36
references.pmid: 7670979
references.citation: Clin Orthop Relat Res. 2011 May;469(5):1442-9
references.pmid: 21042891
references.citation: Eur Radiol. 2010 Oct;20(10):2447-60
references.pmid: 20422195
references.citation: Am J Hum Genet. 2010 Jul 9;87(1):154-60
references.pmid: 20598276
references.citation: Semin Pediatr Neurol. 2011 Dec;18(4):221-9
references.pmid: 22172417
references.citation: J Child Orthop. 2009 Jun;3(3):171-8
references.pmid: 19418086
references.citation: J Bone Joint Surg Am. 2004 Jan;86(1):22-7
references.pmid: 14711941
references.citation: Neuromuscul Disord. 2001 Jul;11(5):489-93
references.pmid: 11404123
references.citation: Clin Orthop Relat Res. 1972 May;84:9-13
references.pmid: 5032855
references.citation: J Bone Joint Surg Am. 2007 Mar;89(3):487-93
references.pmid: 17332096
references.citation: PLoS One. 2013;8(1):e54100
references.pmid: 23382871
references.citation: J Bone Joint Surg Am. 1992 Mar;74(3):448-54
references.pmid: 1548277
references.citation: Dev Med Child Neurol. 2008 Jul;50(7):498-502
references.pmid: 18611198
references.citation: J Bone Joint Surg Am. 2008 Jul;90(7):1501-7
references.pmid: 18594099
references.citation: Plast Reconstr Surg. 1995 Sep;96(4):972-7
references.pmid: 7652075
references.citation: J Med Genet. 1997 Dec;34(12):978-81
references.pmid: 9429137
references.citation: BMJ. 2010 Feb 02;340:c355
references.pmid: 20124368
references.citation: Hum Mol Genet. 2011 Oct 15;20(20):3943-52
references.pmid: 21775501
references.citation: Am J Med Genet A. 2012 Jul;158A(7):1620-7
references.pmid: 22678995
references.citation: Foot Ankle Clin. 2010 Jun;15(2):287-96
references.pmid: 20534356