Experts Study ACL Injury Features with 3D Statistical Shape Modeling

McGowan Institute for Regenerative Medicine affiliated faculty member Richard Debski, PhD, William Kepler Whiteford Faculty Fellow, Co-Director, Orthopaedic Robotics Laboratory, Professor, University of Pittsburgh Departments of Bioengineering and Orthopaedic Surgery, is a co-author of a study to investigate tibiofemoral bony morphology features associated with ACL injury and sex utilizing three-dimensional statistical shape modeling. Other co-authors of this work include:

Sene Polamalu, BS, Bioengineering PhD Student Researcher (third year), Orthopaedic Robotics Laboratory, University of Pittsburgh
Volker Musahl, MD, Blue Cross of Western Pennsylvania Professor, Chief UPMC Sports Medicine Medical Director, Professor, University of Pittsburgh Departments of Orthopaedic Surgery, Bioengineering, and Clinical Translational Science Institute

In the study, statistical shape modeling was employed to assess three-dimensional (3D) bony morphology between:

distal femurs and proximal tibiae of anterior cruciate ligament (acl) injured knees
the contralateral uninjured knees of acl injured subjects
knees with no history of injury

Surface models were created by segmenting bone from bilateral computed-tomography scans of:

20 subjects of their ACL injured knees and non-injured contralateral knees
20 knees of control subjects with no history of a knee injury

Correspondence particles were placed on each surface, and a principal component analysis determined modes of variation in the positions of the correspondence particles describing anatomical variation. ANOVAs assessed the statistical differences of 3D bony morphological features with main effects of injury state and sex.

ACL injured knees were determined to have a more lateral femoral mechanical axis and a greater angle between the long axis and condylar axis of the femur. A smaller anterior-posterior dimension of the lateral tibial plateau was also associated with ACL injured knees.

Results of this study demonstrate that there are more bony morphological features predisposing individuals for ACL injury than previously established. These bony morphological parameters may cause greater internal and valgus torques increasing stresses in the ACL. No differences were determined between the ACL injured knees and their uninjured contralateral knees demonstrating that knees of ACL injured individuals are at similar risk for injury.

Further understanding of the effect of bony morphology on the risk for ACL injury could improve individualized ACL injury treatment and prevention.