C L Abraham1, S J Knight2, C L Peters3, J A Weiss4, A E Anderson5. 1. Department of Orthopaedics, University of Utah, 590 Wakara Way, Salt Lake City, UT 84108, USA; Department of Bioengineering, University of Utah, James LeVoy Sorenson Molecular Biotechnology Building, 36 S. Wasatch Drive, Rm. 3100, Salt Lake City, UT 84112, USA. Electronic address: christine.l.abraham@gmail.com. 2. Department of Orthopaedics, University of Utah, 590 Wakara Way, Salt Lake City, UT 84108, USA. Electronic address: knight.spencer@hotmail.com. 3. Department of Orthopaedics, University of Utah, 590 Wakara Way, Salt Lake City, UT 84108, USA; Department of Bioengineering, University of Utah, James LeVoy Sorenson Molecular Biotechnology Building, 36 S. Wasatch Drive, Rm. 3100, Salt Lake City, UT 84112, USA. Electronic address: chris.peters@hsc.utah.edu. 4. Department of Orthopaedics, University of Utah, 590 Wakara Way, Salt Lake City, UT 84108, USA; Department of Bioengineering, University of Utah, James LeVoy Sorenson Molecular Biotechnology Building, 36 S. Wasatch Drive, Rm. 3100, Salt Lake City, UT 84112, USA; Scientific Computing and Imaging Institute, 72 S Central Campus Drive, Room 3750, Salt Lake City, UT 84112, USA. Electronic address: jeff.weiss@utah.edu. 5. Department of Orthopaedics, University of Utah, 590 Wakara Way, Salt Lake City, UT 84108, USA; Department of Bioengineering, University of Utah, James LeVoy Sorenson Molecular Biotechnology Building, 36 S. Wasatch Drive, Rm. 3100, Salt Lake City, UT 84112, USA; Scientific Computing and Imaging Institute, 72 S Central Campus Drive, Room 3750, Salt Lake City, UT 84112, USA; Department of Physical Therapy, University of Utah, 520 Wakara Way, Suite 240, Salt Lake City, UT 84108, USA. Electronic address: andrew.anderson@hsc.utah.edu.
Abstract
OBJECTIVE: Using a validated, patient-specific finite element (FE) modeling protocol, we evaluated cartilage and labrum (i.e., chondrolabral) mechanics before and after peri-acetabular osteotomy (PAO) to provide insight into the ability of this procedure to improve mechanics in dysplastic hips. DESIGN: Five patients with acetabular dysplasia were recruited in this case-controlled, prospective study. Models, which included anatomy for bone, cartilage, and labrum, were generated from computed tomography (CT) arthrography scans acquired before and after PAO. Cartilage and labrum contact stress and contact area were quantified overall and regionally. Load supported by the labrum, expressed as a percentage of the total hip force, was analyzed. RESULTS: Percent cartilage contact area increased post-operatively overall, medially, and superiorly. Peak acetabular contact stress decreased overall, laterally, anteriorly, and superiorly. Average contact stress decreased overall, laterally, anteriorly, and posteriorly. Only average contact stress on the superior labrum and peak labrum stress overall decreased. Load supported by the labrum did not change significantly. CONCLUSIONS: PAO was efficacious at medializing cartilage contact and reducing cartilage contact stresses, and therefore may minimize deleterious loading to focal cartilage lesions, subchondral cysts, and cartilage delaminations often observed in the lateral acetabulum of dysplastic hips. However, the excessively prominent, hypertrophied labrum of dysplastic hips remains in contact with the femoral head, which continues to load the labrum following PAO. The clinical ramifications of continued labral loading following PAO are not known. However, it is plausible that failure to reduce the load experienced by the labrum could result in end-stage hip OA following PAO.
OBJECTIVE: Using a validated, patient-specific finite element (FE) modeling protocol, we evaluated cartilage and labrum (i.e., chondrolabral) mechanics before and after peri-acetabular osteotomy (PAO) to provide insight into the ability of this procedure to improve mechanics in dysplastic hips. DESIGN: Five patients with acetabular dysplasia were recruited in this case-controlled, prospective study. Models, which included anatomy for bone, cartilage, and labrum, were generated from computed tomography (CT) arthrography scans acquired before and after PAO. Cartilage and labrum contact stress and contact area were quantified overall and regionally. Load supported by the labrum, expressed as a percentage of the total hip force, was analyzed. RESULTS: Percent cartilage contact area increased post-operatively overall, medially, and superiorly. Peak acetabular contact stress decreased overall, laterally, anteriorly, and superiorly. Average contact stress decreased overall, laterally, anteriorly, and posteriorly. Only average contact stress on the superior labrum and peak labrum stress overall decreased. Load supported by the labrum did not change significantly. CONCLUSIONS:PAO was efficacious at medializing cartilage contact and reducing cartilage contact stresses, and therefore may minimize deleterious loading to focal cartilage lesions, subchondral cysts, and cartilage delaminations often observed in the lateral acetabulum of dysplastic hips. However, the excessively prominent, hypertrophied labrum of dysplastic hips remains in contact with the femoral head, which continues to load the labrum following PAO. The clinical ramifications of continued labral loading following PAO are not known. However, it is plausible that failure to reduce the load experienced by the labrum could result in end-stage hip OA following PAO.
Authors: Holly D Thomas-Aitken; Jessica E Goetz; Kevin N Dibbern; Robert W Westermann; Michael C Willey; Timothy S Brown Journal: Clin Orthop Relat Res Date: 2019-05 Impact factor: 4.176
Authors: James D Wylie; Michael P McClincy; Evan K Stieler; Michael B Millis; Young-Jo Kim; Christopher L Peters; Eduardo N Novais Journal: J Hip Preserv Surg Date: 2019-09-17