Publications
30 results found
Hoffer AJ, Beel W, Ng KCG, et al., 2024, The Contribution of Soft Tissue and Bony Stabilizers to the Hip Suction Seal: A Systematic Review of Biomechanical Studies., Am J Sports Med
BACKGROUND: Previous biomechanical studies have identified capsular closure, labral repair or reconstruction, and osteochondroplasty as important surgical interventions to improve hip stability. PURPOSE: To investigate the outcome metrics used to quantify hip stability and assess and measure the relative contributions of the labrum, capsule, and bone to hip stability through a quantitative analysis. STUDY DESIGN: Systematic review and meta-analysis; Level of evidence, 4. METHODS: PubMed and Embase databases were searched using the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. Included studies evaluated cadaveric hip biomechanics related to capsular, labral, and bony management during hip arthroscopy. Studies were assessed for distraction force and distance, fluid measures, and contact forces used to quantify the suction seal. Exclusion criteria included open surgery, arthroplasty, reorientation osteotomy, or traumatic dislocation. RESULTS: A total of 33 biomechanical studies comprising 322 hips that evaluated 1 or more of the following were included: distraction force or distance (24 studies), fluid measures (10 studies), and contact forces (6 studies). Compared with a capsulotomy or capsulectomy, capsular repair or reconstruction demonstrated greater resistance to distraction (standardized mean difference [SMD], 1.13; 95% CI, 0.46-1.80; P = .0009). Compared with a labral tear, a labral repair or reconstruction demonstrated less resistance to distraction (SMD, -0.67; 95% CI, -1.25 to -0.09; P = .02). Compared with a labral debridement, repair or reconstruction demonstrated greater resistance to distraction (SMD, 1.74; 95% CI, 1.23 to 2.26; P < .00001). No quantitative analysis was feasible from studies evaluating the effect of osseous resection due to the heterogeneity in methodology and outcome metrics assessed. CONCLUSION: Most biomechanical evidence supports capsulotomy repair or reconstruction to improve hip distracti
Degen RM, Donnelly E, Toobaie A, et al., 2024, Early Postoperative Activities of Daily Living Do Not Adversely Affect Joint Torques or Translation Regardless of Capsular Condition: A Cadaveric Study., Arthroscopy, Vol: 40, Pages: 362-370
PURPOSE: To evaluate the impact of capsular management on joint constraint and femoral head translations during simulated activities of daily living (ADL). METHODS: Using 6 (n = 6) cadaveric hip specimens, the effect of capsulotomies and repair was then evaluated during simulated ADL. Joint forces and rotational kinematics associated with gait and sitting, adopted from telemeterized implant studies, were applied to the hip using a 6-degrees of freedom (DOF) joint motion simulator. Testing occurred after creation of portals, interportal capsulotomy (IPC), IPC repair, T-capsulotomy (T-Cap), partial T-Cap repair, and full T-Cap repair. The anterior-posterior (AP), medial-lateral (ML), and axial compression DOFs were operated in force control, whereas flexion-extension, adduction-abduction, and internal-external rotation were manipulated in displacement control. Resulting femoral head translations and joint reaction torques were recorded and evaluated. Subsequently, the mean-centered range of femoral head displacements and peak signed joint restraint torques were calculated and compared. RESULTS: During simulated gait and sitting, the mean range of AP femoral head displacements with respect to intact exceeded 1% of the femoral head diameter after creating portals, T-Caps, and partial T-Cap repair (Wilcoxon signed rank P < .05); the mean ranges of ML displacements did not. Deviations in femoral head kinematics varied by capsule stage but were never very large. No consistent trends with respect to alterations in peak joint restrain torques were observed. CONCLUSIONS: In this cadaveric biomechanical study, capsulotomy and repair minimally affected resultant femoral head translation and joint torques during simulated ADLs. CLINICAL RELEVANCE: The tested ADLs appear safe to perform after surgery, regardless of capsular status, because adverse kinematics were not observed. However, further study is required to determine the importance of capsular repair beyond time-ze
Ng KC, Bankes M, El Daou H, et al., 2022, Capsular mechanics after periacetabular osteotomy for hip dysplasia, The Journal of Bone and Joint Surgery, Vol: 104, Pages: 1015-1023, ISSN: 0021-9355
Background: Hip dysplasia is characterized by insufficient acetabular coverage around the femoral head, which leads to instability, pain, and injury. Periacetabular osteotomy (PAO) aims to restore acetabular coverage and function, but its effects on capsular mechanics and joint stability are still unclear. The purpose of this study was to examine the effects of PAO on capsular mechanics and joint range of motion in dysplastic hips.Methods: Twelve cadaveric dysplastic hips (denuded to bone and capsule) were mounted onto a robotic tester and tested in multiple positions: (1) full extension, (2) neutral 0°, (3) flexion of 30°, (4) flexion of 60°, and (5) flexion of 90°. In each position, the hips underwent internal and external rotation, abduction, and adduction using 5 Nm of torque. Each hip then underwent PAO to reorient the acetabular fragment, preserving the capsular ligaments, and was retested.Results: The PAO reduced internal rotation in flexion of 90° (∆IR = –5°; p = 0.003), and increased external rotation in flexion of 60° (∆ER = +7°; p = 0.001) and flexion of 90° (∆ER = +11°; p = 0.001). The PAO also reduced abduction in extension (∆ABD = –10°; p = 0.002), neutral 0° (∆ABD = –7°; p = 0.001), and flexion of 30° (∆ABD = –8°; p = 0.001), but increased adduction in neutral 0° (∆ADD = +9°; p = 0.001), flexion of 30° (∆ADD = +11°; p = 0.002), and flexion of 60° (∆ADD = +11°; p = 0.003).Conclusions: PAO caused reductions in hip abduction and internal rotation but greater increases in hip adduction and external rotation. The osseous acetabular structure and capsule both play a role in the balance between joint mobility and stability after PAO.
Ng KCG, 2022, <i>CORR</i> Insights®: How Does Chondrolabral Damage and Labral Repair Influence the Mechanics of the Hip in the Setting of Cam Morphology? A Finite-Element Modeling Study, CLINICAL ORTHOPAEDICS AND RELATED RESEARCH, Vol: 480, Pages: 616-618, ISSN: 0009-921X
Yarwood W, Kumar KHS, Ng KCG, et al., 2022, Biomechanics of Cam Femoroacetabular Impingement: A Systematic Review, ARTHROSCOPY-THE JOURNAL OF ARTHROSCOPIC AND RELATED SURGERY, Vol: 38, Pages: 174-189, ISSN: 0749-8063
- Author Web Link
- Cite
- Citations: 2
Ng KCG, Bankes M, El Daou H, et al., 2021, Cam osteochondroplasty for femoroacetabular impingement increases microinstability in deep flexion: A cadaveric study, Arthroscopy: The Journal of Arthroscopy and Related Surgery, Vol: 37, Pages: 159-170, ISSN: 0749-8063
Purpose: The purpose of this in vitro cadaveric study was to examine the contributions of each surgical stage during cam femoroacetabular impingement (FAI) surgery (i.e., intact cam hip, T8 capsulotomy, cam resection, capsular repair) towards hip range of motion, translations, and microinstability.Methods: Twelve cadaveric cam hips were denuded to the capsule and mounted onto a robotic tester. Hips were positioned in several flexion positions: Full Extension, Neutral 0°, Flexion 30°, and Flexion 90°; and performed internal-external rotations to 5-Nm torque in each position. Hips underwent a series of surgical stages (T-capsulotomy, cam resection, capsular repair) and was retested after each stage. Changes in range of motion, translation, and microinstability (overall translation normalized by femoral head radius) were measured after each stage.Results: For range of motion, cam resection increased internal rotation at Flexion 90° (ΔIR = +6°, P = .001), but did not affect external rotation. Capsular repairs restrained external rotations compared to the cam resection stage (ΔER = –4 to –8°, P ≤ .04). For translations, the hip translated after cam resection at Flexion 90° in the medial-lateral plane (ΔT = +1.9 mm, P = .04), relative to the intact and capsulotomy stages. For microinstability, capsulotomy increased microinstability in Flexion 30° (ΔM = +0.05; P = .003), but did not further increase after cam resection. At Flexion 90°, microinstability did not increase after capsulotomy (ΔM = +0.03; P = .2, d = .24), but substantially increased after cam resection (ΔM = +0.08; P = .03), accounting for a 31% change with respect to the intact stage.Conclusions: Cam resection increased microinstability by 31% during deep hip flexion relative to the intact hip. This suggests that iatrogenic microinstability may be due to separation of the labral seal and resected contour of the femoral head.
Munford M, Ng KCG, Jeffers J, 2020, Mapping the multi-directional mechanical properties of bone in the proximal tibia, Advanced Functional Materials, Vol: 30, Pages: 1-9, ISSN: 1616-301X
The remodeling behavior of bone is influenced by its mechanical environment. By mapping bone's mechanical properties in detail, orthopedic implants with respect to its mechanical properties could stimulate and harness remodeling to improve patient outcomes. In this study, multiaxial apparent modulus and strength of cadaveric proximal tibial bone are mapped and predicted from computed tomography (CT) derived apparent density. Group differences are identified from testing order, subchondral depth, condyle, and sub‐meniscal bone with covariates; age and gender. Axial modulus is 50% greater than the transverse modulus. Medial axial modulus is 30% greater than the lateral side. On the lateral side, axial modulus decreases by 50% from proximal to 25 mm distal. On the medial side, axial modulus remains relatively constant. Differences are quantified for density and multiaxial modulus across all subchondral depths, and different power law relationships are provided for each location. Density explains 75% of variation when grouped by subchondral depth and condyle. Yield strength is well‐predicted across all test directions, with density predicting 81% of axial strength variation and no differences over subchondral depth. Quantified mapping of bone multiaxial modulus based on condyle and subchondral depth is shown for the first time in a clinically viable protocol using conventional CT.
Catelli DS, Ng KCG, Wesseling M, et al., 2020, Hip Muscle Forces and Contact Loading During Squatting After Cam-Type FAI Surgery, Journal of Bone and Joint Surgery: American Volume, ISSN: 0021-9355
Ng KCG, Bankes MJK, Cobb J, et al., 2020, Biomechanics of the Native Hip from Normal to Instability, Hip Dysplasia Understanding and Treating Instability of the Native Hip, Editors: Beaulé, Publisher: Springer, Pages: 55-70, ISBN: 9783030333577
This book represents the most advanced understanding of diagnosis and management of hip dysplasia in the young adult, written by the world’s leading experts and covering advanced imaging and biomechanical studies as well as latest ...
Ng KCG, Jeffers JRT, Beaule PE, 2019, Hip Joint Capsular Anatomy, Mechanics, and Surgical Management, JOURNAL OF BONE AND JOINT SURGERY-AMERICAN VOLUME, Vol: 101, Pages: 2141-2151, ISSN: 0021-9355
- Author Web Link
- Open Access Link
- Cite
- Citations: 41
Catelli DS, Ng KCG, Kowalski E, et al., 2019, Modified gait patterns due to cam FAI syndrome remain unchanged after surgery, Gait & Posture, Vol: 72, Pages: 135-141, ISSN: 0966-6362
Ghouse S, Reznikov N, Boughton O, et al., 2019, The design and in vivo testing of a locally stiffness-matched porous scaffold, Applied Materials Today, Vol: 15, Pages: 377-388, ISSN: 2352-9407
An increasing volume of work supports utilising the mechanobiology of bone for bone ingrowth into a porous scaffold. However, typically during in vivo testing of implants, the mechanical properties of the bone being replaced are not quantified. Consequently there remains inconsistencies in the literature regarding ‘optimum’ pore size and porosity for bone ingrowth. It is also difficult to compare ingrowth results between studies and to translate in vivo animal testing to human subjects without understanding the mechanical environment. This study presents a clinically applicable approach to determining local bone mechanical properties and design of a scaffold with similar properties. The performance of the scaffold was investigated in vivo in an ovine model.The density, modulus and strength of trabecular bone from the medial femoral condyle from ovine bones was characterised and power-law relationships were established. A porous titanium scaffold, intended to maintain bone mechanical homeostasis, was additively manufactured and implanted into the medial femoral condyle of 6 ewes. The stiffness of the scaffold varied throughout the heterogeneous structure and matched the stiffness variation of bone at the surgical site. Bone ingrowth into the scaffold was 10.73 ± 2.97% after 6 weeks. Fine woven bone, in the interior of the scaffold, and intense formations of more developed woven bone overlaid with lamellar bone at the implant periphery were observed. The workflow presented will allow future in vivo testing to test specific bone strains on bone ingrowth in response to a scaffold and allow for better translation from in vivo testing to commercial implants.
Logishetty K, van Arkel RJ, Ng KC, et al., 2019, Hip capsule biomechanics after arthroplasty - the effect of implant, approach and surgical repair, Bone and Joint Journal, Vol: 101-B, Pages: 426-434, ISSN: 2049-4394
AimsThe hip’s capsular ligaments passively restrain extreme range of movement (ROM) by wrapping around the native femoral head/neck. We determined the effect of hip resurfacing arthroplasty (HRA), dual-mobility total hip arthroplasty (DM-THA), conventional THA, and surgical approach on ligament function.Materials and MethodsEight paired cadaveric hip joints were skeletonized but retained the hip capsule. Capsular ROM restraint during controlled internal rotation (IR) and external rotation (ER) was measured before and after HRA, DM-THA, and conventional THA, with a posterior (right hips) and anterior capsulotomy (left hips).ResultsHip resurfacing provided a near-native ROM with between 5° to 17° increase in IR/ER ROM compared with the native hip for the different positions tested, which was a 9% to 33% increase. DM-THA generated a 9° to 61° (18% to 121%) increase in ROM. Conventional THA generated a 52° to 100° (94% to 199%) increase in ROM. Thus, for conventional THA, the capsule function that exerts a limit on ROM is lost. It is restored to some extent by DM-THA, and almost fully restored by hip resurfacing. In positions of low flexion/extension, the posterior capsulotomy provided more normal function than the anterior, possibly because the capsule was shortened during posterior repair. However, in deep flexion positions, the anterior capsulotomy functioned better.ConclusionNative head-size and capsular repair preserves capsular function after arthroplasty. The anterior and posterior approach differentially affect postoperative biomechanical function of the capsular ligaments.
Ng KCG, El Daou H, Bankes M, et al., 2019, Hip joint torsional loading before and after cam femoroacetabular impingement surgery, American Journal of Sports Medicine, Vol: 47, Pages: 420-430, ISSN: 0363-5465
Background: Surgical management of cam femoroacetabular impingement (FAI) aims to preserve the native hip and restore joint function, though it is unclear how the capsulotomy, cam deformity, and capsular repair influence joint mechanics to balance functional mobility.Purpose: The purpose was to examine the contributions of the capsule and cam deformity to hip joint mechanics. Using in vitro, cadaveric methods, we examined the individual effects of the surgical capsulotomy, cam resection, and capsular repair towards passive range of motion and resistance of applied torque.Study Design: Descriptive laboratory study.Methods: Twelve cadaveric hips with cam deformities (n = 12) were skeletonized to the capsule and mounted onto a robotic testing platform. The robot positioned each intact hip in multiple testing positions: 1) Extension, 2) Neutral 0°, 3) Flexion 30°, 4) Flexion 90°, 5) flexion-adduction and internal rotation (FADIR), 6) flexion-abduction and external rotation (FABER); and performed applicable internal and external rotations, recording the neutral path of motion until a 5-Nm torque was reached in each rotational direction. Each hip then underwent a series of surgical stages (T-capsulotomy, cam resection, capsular repair) and was retested to reach 5 Nm internal and external torque again after each stage. In addition, during the capsulotomy and cam resection stages, the initial intact hip’s recorded path of motion was replayed to measure changes in resisted torque.Results: Examining changes in motion, external rotation increased substantially after capsulotomies, but internal rotation only further increased at Flexion 90° (change = +32%, P = .001, d = .58) and FADIR (change = +33%, P < .001, d = .51) after cam resections. Capsular repair provided marginal restraint for internal rotation, but restrained the external rotation compared to the capsulotomy stage. Examining changes in torque, both internal and external torque resistance dec
El Daou H, Ng KCG, Van Arkel R, et al., 2019, Robotic hip joint testing: Development and experimental protocols, MEDICAL ENGINEERING & PHYSICS, Vol: 63, Pages: 57-62, ISSN: 1350-4533
- Author Web Link
- Open Access Link
- Cite
- Citations: 10
Beaule PE, Grammatopoulos G, Speirs A, et al., 2018, Unravelling the hip pistol grip/cam deformity: Origins to joint degeneration, JOURNAL OF ORTHOPAEDIC RESEARCH, Vol: 36, Pages: 3125-3135, ISSN: 0736-0266
- Author Web Link
- Cite
- Citations: 25
Ng KCG, Mantovani G, Lamontagne M, et al., 2018, Cam FAI and Smaller Neck Angles Increase Subchondral Bone Stresses During Squatting, Clinical Orthopaedics and Related Research, Pages: 1-1, ISSN: 0009-921X
Ng KCG, Mantovani G, Modenese L, et al., 2018, Altered walking and muscle patterns reduce hip contact forces in individuals with symptomatic cam femoroacetabular impingement, American Journal of Sports Medicine, Vol: 46, Pages: 2615-2623, ISSN: 0363-5465
Background:Cam-type femoroacetabular impingement (FAI) is a causative factor for hip pain and early hip osteoarthritis. Although cam FAI can alter hip joint biomechanics, it is unclear what role muscle forces play and how they affect the hip joint loading.Purpose/Hypothesis:The purpose was to examine the muscle contributions and hip contact forces in individuals with symptomatic cam FAI during level walking. Patients with symptomatic cam FAI would demonstrate different muscle and hip contact forces during gait.Study Design:Controlled laboratory study.Methods:Eighteen patients with symptomatic cam FAI were matched for age and body mass index with 18 control participants. Each participant’s walking kinematics and kinetics were recorded throughout a gait cycle (ipsilateral foot-strike to ipsilateral foot-off) by use of a motion capture system and force plates. Muscle and hip contact forces were subsequently computed by use of a musculoskeletal modeling program and static optimization methods.Results:The FAI group walked slower and with shorter steps, demonstrating reduced joint motions and moments during contralateral foot-strike, compared with the control group. The FAI group showed reduced psoas major (median, 1.1 newtons per bodyweight [N/BW]; interquartile range [IQR], 1.0-1.5 N/BW) and iliacus forces (median, 1.2 N/BW; IQR, 1.0-1.6 N/BW), during contralateral foot-strike, compared with the control group (median, 1.6 N/BW; IQR, 1.3-1.6 N/BW, P = .004; and median, 1.5 N/BW; IQR, 1.3-1.6 N/BW, P = .03, respectively), which resulted in lower hip contact forces in the anterior (P = .026), superior (P = .02), and medial directions (P = .038). The 3 vectors produced a resultant peak force at the anterosuperior aspect of the acetabulum for both groups, with the FAI group demonstrating a substantially lower magnitude.Conclusion:FAI participants altered their walking kinematics and kinetics, especially during contralateral foot-strike, as a protective mechanism, which
van Arkel R, Ng KCG, Muirhead-Allwood S, et al., 2018, Capsular ligament function after total hip arthroplasty, Journal of Bone and Joint Surgery: American Volume, Vol: 100, Pages: 1-10, ISSN: 0021-9355
Background: The hip joint capsule passively restrains extreme range of motion, protecting the native hip against impingement, dislocation, and edge-loading. We hypothesized that following total hip arthroplasty (THA), the reduced femoral head size impairs this protective biomechanical function.Methods: In cadavers, THA was performed through the acetabular medial wall, preserving the entire capsule, and avoiding the targeting of a particular surgical approach. Eight hips were examined. Capsular function was measured by rotating the hip in 5 positions. Three head sizes (28, 32, and 36 mm) with 3 neck lengths (anatomical 0, +5, and +10 mm) were compared.Results: Internal and external rotation range of motion increased following THA, indicating late engagement of the capsule and reduced biomechanical function (p < 0.05). Internal rotation was affected more than external. Increasing neck length reduced this hypermobility, while too much lengthening caused nonphysiological restriction of external rotation. Larger head sizes only slightly reduced hypermobility.Conclusions: Following THA, the capsular ligaments were unable to wrap around the reduced-diameter femoral head to restrain extreme range of motion. The posterior capsule was the most affected, indicating that native posterior capsule preservation is not advantageous, at least in the short term. Insufficient neck length could cause capsular dysfunction even if native ligament anatomy is preserved, while increased neck length could overtighten the anterior capsule.Clinical Relevance: Increased understanding of soft-tissue balancing following THA could help to prevent instability and improve early function. This study illustrates how head size and neck length influence the biomechanical function of the hip capsule in the early postoperative period.
Ng KCG, Lamontagne M, Jeffers J, et al., 2018, Anatomic predictors of sagittal hip and pelvic motions in patients with a cam deformity, American Journal of Sports Medicine, Vol: 46, Pages: 1331-1342, ISSN: 0363-5465
Background:As there is a high prevalence of patients with cam deformities and no ongoing hip dysfunction, understanding the biomechanical factors predicting the onset of symptoms and degenerative changes is critical. One such variable is how the spinopelvic parameters may influence hip and pelvic sagittal mobility.Hypothesis/Purpose:Pelvic incidence may predict sagittal hip and pelvic motions during walking and squatting. The purpose was to determine which anatomic characteristics were associated with symptoms and how they influenced functional hip and pelvic ranges of motion (ROMs) during walking and squatting.Study Design:Controlled laboratory study.Methods:Fifty-seven participants underwent computed tomography and were designated either symptomatic (n = 19, cam deformity with pain), asymptomatic (n = 19, cam deformity with no pain), or control (n = 19, no cam deformity or pain). Multiple femoral (cam deformity, neck angle, torsion), acetabular (version, coverage), and spinopelvic (pelvic tilt, sacral slope, pelvic incidence) parameters were measured from each participant’s imaging data, and sagittal hip and pelvic ROMs during walking and squatting were recorded using a motion capture system.Results:Symptomatic participants had large cam deformities, smaller femoral neck-shaft angles, and larger pelvic incidence angles compared with the asymptomatic and control participants. Discriminant function analyses confirmed that radial 1:30 alpha angle (λ1 = 0.386), femoral neck-shaft angle (λ2 = 0.262), and pelvic incidence (λ3 = 0.213) (P < .001) were the best anatomic parameters to classify participants with their groups. Entering these 3 parameters into a hierarchical linear regression, significant regressions were achieved for hip ROM only when pelvic incidence was included for walking (R2 = 0.20, P = .01) and squatting (R2 = 0.14, P = .04). A higher pelvic incidence decreased walking hip ROM (r = −0.402, P = .004). Although symptom
Grammatopoulos G, Speirs AD, Ng KCG, et al., 2018, Acetabular and spino‐pelvic morphologies are different in subjects with symptomatic cam femoro‐acetabular impingement, Journal of Orthopaedic Research, ISSN: 0736-0266
Ng KCG, Mantovani G, Lamontagne M, et al., 2016, Increased Hip Stresses Resulting From a Cam Deformity and Decreased Femoral Neck-Shaft Angle During Level Walking, Clinical Orthopaedics and Related Research®, Vol: 475, Pages: 998-1008, ISSN: 0009-921X
Ng KCG, Lamontagne M, Labrosse MR, et al., 2016, Comparison of anatomical parameters of cam femoroacetabular impingement to evaluate hip joint models segmented from CT data, Computer Methods in Biomechanics and Biomedical Engineering: Imaging & Visualization, Pages: 1-10, ISSN: 2168-1163
Ng KCG, Lamontagne M, Beaule PE, 2016, Differences in anatomical parameters between the affected and unaffected hip in patients with bilateral cam-type deformities, CLINICAL BIOMECHANICS, Vol: 33, Pages: 13-19, ISSN: 0268-0033
- Author Web Link
- Cite
- Citations: 25
Mantovani G, Ng KCG, Lamontagne M, 2016, Regression models to predict hip joint centers in pathological hip population, GAIT & POSTURE, Vol: 44, Pages: 48-54, ISSN: 0966-6362
- Author Web Link
- Cite
- Citations: 8
Ng KCG, Lamontagne M, Labrosse MR, et al., 2016, Hip Joint Stresses Due to Cam-Type Femoroacetabular Impingement: A Systematic Review of Finite Element Simulations, PLOS One, Vol: 11, ISSN: 1932-6203
Background: The cam deformity causes the anterosuperior femoral head to obstruct with the acetabulum, resulting in femoroacetabular impingement (FAI) and elevated risks of early osteoarthritis. Several finite element models have simulated adverse loading conditions due to cam FAI, to better understand the relationship between mechanical stresses and cartilage degeneration. Our purpose was to conduct a systematic review and examine the previous finite element models and simulations that examined hip joint stresses due to cam FAI.Methods: The systematic review was conducted to identify those finite element studies of cam-type FAI. The review conformed to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and studies that reported hip joint contact pressures or stresses were included in the quantitative synthesis.Results: Nine articles studied FAI morphologies using finite element methods and were included in the qualitative synthesis. Four articles specifically examined contact pressures and stresses due to cam FAI and were included in the quantitative synthesis. The studies demonstrated that cam FAI resulted in substantially elevated contact pressures (median = 10.4 MPa, range = 8.5–12.2 MPa) and von Mises stresses (median 15.5 MPa, range = 15.0–16.0 MPa) at the acetabular cartilage; and elevated maximum-shear stress on the bone (median = 15.2 MPa, range = 14.3–16.0 MPa), in comparison with control hips, during large amplitudes of hip motions. Many studies implemented or adapted idealized, ball-and-cup, parametric models to predict stresses, along with homogeneous bone material properties and in vivo instrumented prostheses loading data.Conclusion: The formulation of a robust subject-specific FE model, to delineate the pathomechanisms of FAI, remains an ongoing challenge. The available literature provides clear insight into the estimated stresses due to the cam deformity and provides an assessment of its risks leading
Lamontagne M, Ng KCG, Mantovani G, et al., 2015, Biomechanics of Femoroacetabular Impingement, Sport Injuries, Editors: Doral, Karlsson
Femoroacetabular impingement of type cam (FAI) is prevalent for young athletic males. More evidences suggest that FAI is a leading factor for the development of hip OA. The purpose of this work is to present the common symptomatology, the hip geometrical variability, and the hip biomechanics adaptation in FAI individuals. FAI seems to be a combination of factors among the pain symptom, positive indications from physical examinations, a high alpha angle observed from imaging data and a limited mobility at the femoroacetabular and sacrolumbar joint. No associations can be found between symptoms and alpha angles, suggesting that pain due to mechanical impingement is not adequate to assess the presence and severity of the morphology. Consequently, providing clinicians with a more thorough assessment of specific anatomical measurements, hip and pelvis biomechanics, muscle contraction patterns and joint loading, it would help identify those at greater risk of requiring conservative or non-conservative intervention.
Ng KCG, Lamontagne M, Adamczyk AP, et al., 2015, Patient-Specific Anatomical and Functional Parameters Provide New Insights into the Pathomechanism of Cam FAI, CLINICAL ORTHOPAEDICS AND RELATED RESEARCH, Vol: 473, Pages: 1289-1296, ISSN: 0009-921X
- Author Web Link
- Cite
- Citations: 60
Lamontagne M, Ng KCG, Mantovani G, et al., 2014, Biomechanics of Femoroacetabular Impingement, Sports Injuries, Publisher: Springer Berlin Heidelberg, Pages: 1-14
Ng KCG, Rouhi G, Lamontagne M, et al., 2012, Finite Element Analysis Examining the Effects of Cam FAI on Hip Joint Mechanical Loading Using Subject-Specific Geometries During Standing and Maximum Squat., HSS J, Vol: 8, Pages: 206-212
BACKGROUND: Cam femoroacetabular impingement (FAI) can impose elevated mechanical loading in the hip, potentially leading to an eventual mechanical failure of the joint. Since in vivo data on the pathomechanisms of FAI are limited, it is still unclear how this deformity leads to osteoarthritis. PURPOSE: The purpose of this study was to examine the effects of cam FAI on hip joint mechanical loading using finite element analysis, by incorporating subject-specific geometries, kinematics, and kinetics. QUESTIONS: The research objectives were to address and determine: (1) if hips with cam FAI demonstrate higher maximum shear stresses, in comparison with control hips; (2) the magnitude of the peak maximum shear stresses; and (3) the locations of the peak maximum shear stresses. METHODS: Using finite element analysis, two patient models were control-matched and simulated during quasi-static positions from standing to squatting. Intersegmental hip forces, from a previous study, were applied to the subject-specific hip geometries, segmented from CT data, to evaluate the maximum shear stresses on the acetabular cartilage and underlying bone. RESULTS: Peak maximum shear stresses were found at the anterosuperior region of the underlying bone during squatting. The peaks at the anterosuperior acetabulum were substantially higher for the patients (15.2 ± 1.8 MPa) in comparison with the controls (4.5 ± 0.1 MPa). CONCLUSIONS: Peaks were not situated on the cartilage, but instead located on the underlying bone. The results correspond with the locations of initial cartilage degradation observed during surgical treatment and from MRI. CLINICAL RELEVANCE: These findings support the pathomechanism of cam FAI. Changes may originate from the underlying subchondral bone properties rather than direct shear stresses to the articular cartilage.
This data is extracted from the Web of Science and reproduced under a licence from Thomson Reuters. You may not copy or re-distribute this data in whole or in part without the written consent of the Science business of Thomson Reuters.