How Does Chondrolabral Damage and Labral Repair Influence the Mechanics of the Hip in the Setting of Cam Morphology? A Finite-Element Modeling Study

Abstract

Background Individuals with cam morphology are prone to chondrolabral injuries that may progress to osteoarthritis. The mechanical factors responsible for the initiation and progression of chondrolabral injuries in these individuals are not well understood. Additionally, although labral repair is commonly performed during surgical correction of cam morphology, the isolated mechanical effect of labral repair on the labrum and surrounding cartilage is unknown.The institution of one or more of the authors (JNT, JAW) has received, during the study period, funding from the National Science Foundation, and the LS Peery Foundation. The institution of one or more of the authors (AEA) has received, during the study period, funding from National Institutes of Health. One of the authors (TGM) certifies receipt of personal payments or benefits, during the study period, in an amount USD 10,000 to USD 100,000 from Arthrex. One of the authors (GAA) certifies receipt of personal payments or benefits, during the study period, in an amount less than USD 10,000 from Allosource. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request. Clinical Orthopaedics and Related Research® neither advocates nor endorses the use of any treatment, drug, or device. Readers are encouraged to always seek additional information, including FDA-approval status, of any drug or device prior to clinical use. Ethical approval for this study was obtained from University of Utah IRB #51053.

Hip Contact Force Magnitude and Regional Loading Patterns Are Altered in Those with Femoroacetabular Impingement Syndrome

“…4A). More concentrated loading in those with FAI syndrome, compared with controls, concurs with reports of higher peak contact pressures and cartilage stresses revealed by finite element analysis (16,23,24,53). Moreover, concentration occurred when anteroposterior and vertical acetabular contact force magnitudes were largest (Figs.…”

“…However, the method used to estimate hip contact forces in these past studies (7,16,20) was insensitive to the peculiar muscle activation patterns adopted by those with FAI syndrome (19,21,22). Separately, finite element analyses report higher contact pressure (16,23) and more concentrated cartilage stresses during walking (16,23,24) and higher subchondral stresses, but only during squatting (25). Overall, the literature suggests regional loading patterns of the hip’s articular surfaces, and not just magnitude of contact force, may be altered in individuals with FAI syndrome compared with controls (3–8,16,19–24).…”

“…The spread of regional loading was then calculated as the arc length from average regional loading to the time-varying path of articular loading. articular surfaces, and not just magnitude of contact force, may be altered in individuals with FAI syndrome compared with controls (3)(4)(5)(6)(7)(8)16,(19)(20)(21)(22)(23)(24).…”

Hip & Pelvis

“…In this nicely conceived study from Salt Lake City (Utah, USA) , the authors set out to understand the complex relationship between cam morphology, labral year, and the progression to osteoarthritis of the hip joint. 8 The authors designed a series of finite element analysis experiments with the aim of establishing how cam morphology damages articular cartilage, how chondrolabral damage alters the mechanical environment around the damage, and how labral repair affects the mechanical environment. The model was set up to evaluate a range of biomechanical factors, including shear stress, tensile strain, contact pressure, and fluid pressure, and the authors used two real-world grounded hip models.…”

Changes in hip joint contact stress during a gait cycle based on the individualized modeling method of “gait-musculoskeletal system-finite element”

“…In previous biomechanical studies [ 13 , 14 ], the muscle forces around one person’s joints obtained in the laboratory were loaded into another person’s FE model in the form of loads, while ignoring the differences in individualized muscle forces and the difference in hip joint morphology. These studies did not carry out individualized research.…”