title: Acetabular cartilage defects cause altered hip and knee joint coordination variability during gait.
abstract: BACKGROUND
  Patients with acetabular cartilage defects reported increased pain and disability compared to those without acetabular cartilage defects. The specific effects of acetabular cartilage defects on lower extremity coordination patterns are unclear. The purpose of this study was to determine hip and knee joint coordination variability during gait in those with and without acetabular cartilage defects.
  
  
  METHODS
  A combined approach, consisting of a semi-quantitative MRI-based quantification method and vector coding, was used to assess hip and knee joint coordination variability during gait in those with and without acetabular cartilage lesions.
  
  
  RESULTS
  The coordination variability of the hip flexion-extension/knee rotation, hip abduction-adduction/knee rotation, and hip rotation/knee rotation joint couplings were reduced in the acetabular lesion group compared to the control group during loading response of the gait cycle. The lesion group demonstrated increased variability in the hip flexion-extension/knee rotation and hip abduction-adduction/knee rotation joint couplings, compared to the control group, during the terminal stance/pre-swing phase of gait.
  
  
  CONCLUSIONS
  Reduced variability during loading response in the lesion group may suggest reduced movement strategies and a possible compensation mechanism for lower extremity instability during this phase of the gait cycle. During terminal stance/pre-swing, a larger variability in the lesion group may suggest increased movement strategies and represent a compensation or pain avoidance mechanism caused by the load applied to the hip joint.
authors: Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California-San Francisco, 185 Berry Street, Suite 350, San Francisco, CA 94107, USA. Electronic address: michael.samaan@ucsf.edu.
authors: Michael A
authors: MA
authors: Samaan
authors: Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California-San Francisco, 185 Berry Street, Suite 350, San Francisco, CA 94107, USA. Electronic address: hsiang-ling.teng@ucsf.edu.
authors: Hsiang-Ling
authors: HL
authors: Teng
authors: Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California-San Francisco, 185 Berry Street, Suite 350, San Francisco, CA 94107, USA; Division of Physical Therapy, College of Health Professions, Medical University of South Carolina, 151B Rutledge Avenue, MSC 962, Room B309, Charleston, SC 29425, USA. Electronic address: kumarde@musc.edu.
authors: Deepak
authors: D
authors: Kumar
authors: Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California-San Francisco, 185 Berry Street, Suite 350, San Francisco, CA 94107, USA. Electronic address: sonia.lee@ucsf.edu.
authors: Sonia
authors: S
authors: Lee
authors: Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California-San Francisco, 185 Berry Street, Suite 350, San Francisco, CA 94107, USA. Electronic address: thomas.link@ucsf.edu.
authors: Thomas M
authors: TM
authors: Link
authors: Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California-San Francisco, 185 Berry Street, Suite 350, San Francisco, CA 94107, USA. Electronic address: sharmila.majumdar@ucsf.edu.
authors: Sharmila
authors: S
authors: Majumdar
authors: Musculoskeletal Quantitative Imaging Research Group, Department of Radiology and Biomedical Imaging, University of California-San Francisco, 185 Berry Street, Suite 350, San Francisco, CA 94107, USA; Department of Physical Therapy and Rehabilitation Science, University of California-San Francisco, 1500 Owens Street, Suite 400, San Francisco, CA 94158, USA. Electronic address: richard.souza@ucsf.edu.
authors: Richard B
authors: RB
authors: Souza
mesh_terms: D000077:Acetabulum / Q000503:physiopathology*; D000203:Activities of Daily Living; D000328:Adult; D000368:Aged; D002358:Cartilage, Articular / Q000503:physiopathology*; D005260:Female; D005684:Gait / Q000502:physiology*; D006621:Hip Joint / Q000502:physiology*; D006801:Humans; D007719:Knee Joint / Q000502:physiology*; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D009068:Movement / Q000502:physiology; D015207:Osteoarthritis, Hip / Q000503:physiopathology*; D012189:Retrospective Studies
keywords: Acetabular cartilage lesions; Gait; Joint coordination; Lower extremity; MRI; Vector coding