Acetabular cartilage defects cause altered hip and knee joint coordination variability during gait

• This study reports on joint coordination in those with acetabular cartilage lesions.
• Vector coding was used to analyze hip and knee joint coordination variability.
• People with acetabular cartilage lesions exhibit altered joint coordination variability.
• Vector coding may be a useful method in analyzing hip joint pathologies during gait.

BackgroundPatients 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.MethodsA 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.FindingsThe 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.InterpretationReduced 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.