Hip Morphological Characteristics and Range of Internal Rotation in Femoroacetabular Impingement

Background: Femoroacetabular impingement (FAI) is increasingly recognized as a cause of hip pain in young adults. The condition leads to chondrolabral separation and chondral delamination and eventually predisposes to osteoarthritis of the hip. FAI that inflicts cartilage damage has been observed in hips with abnormal morphological characteristics and is related to a long-term evolution toward osteoarthritis. Arthroscopic surgery, which allows for correction of morphological characteristics and restores impingement-free motions, is the current standard of treatment. Hypothesis: Arthroscopic cam resection can restore the normal mechanical environment of the hip joint in cam-type FAI. Study Design: Descriptive laboratory study. Methods: Patient-specific discrete element models from 10 patients with cam-type FAI (all male; age, 18-40 years) were defined based on preoperative computed tomography scans and postoperative magnetic resonance imaging (MRI) scans. Complete cam resection postoperatively on MRI was confirmed with alpha angles <55°. The preoperative and postoperative peak contact stress findings during impingement testing were compared against a matched control group. Results: Peak contact stress was significantly elevated in patients with cam-type FAI during impingement testing, with increasing amounts of internal hip rotation (26.6 ± 11.64 MPa in cam patients preoperatively, 12.1 ± 4.62 MPa in those same patients postoperatively, and 11.4 ± 1.72 MPa in the virtual control group during impingement testing at 20° of internal hip rotation; P < .01). This effect was normalized after arthroscopic cam resection and loading patterns matched those of the control group. Conclusion: Accurate arthroscopic cam resection restored the normal peak joint contact stresses in the hip joint. This highlights the importance of early and complete cam resections in the face of a positive diagnosis of cam-type FAI. Clinical Relevance: Treatment of cam-type FAI effectively normalizes hip joint contact mechanics.

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Sclerotic lesions of the femoral head–neck junction for diagnosis of femoroacetabular impingement

Journal of Orthopaedic Surgery ◽

10.1177/2309499020924161 ◽

2020 ◽

Vol 28 (2) ◽

pp. 230949902092416

Author(s):

Takehito Hananouchi ◽

Stephen Kenji Aoki

Keyword(s):

Femoral Head ◽

Femoroacetabular Impingement ◽

Morphological Characteristics ◽

Control Group ◽

Diagnostic Feature ◽

Pixel Intensity ◽

Plain Radiographs ◽

Sclerotic Lesions ◽

Head Neck ◽

Neck Junction

The morphological characteristics associated with a diagnosis of femoroacetabular impingement (FAI) observed on plain radiographs can also be seen in subjects without hip joint symptoms. Therefore, the purpose of this study was to investigate whether sclerotic lesions on femoral head–neck junction (FHNJ) could be used as a supplemental diagnostic feature. A total of 128 hips from 119 patients (43 male and 76 female) diagnosed with FAI and 24 hips from 21 patients (2 male and 19 female) with other hip pathologies as control were compared in this study. Using standing frog-leg plain radiographs, the prevalence of sclerotic lesions on the FHNJ was established. Additionally, the pixel intensity (PI) of the sclerotic lesions between the FAI and the control groups were quantitatively compared. Sclerotic lesions were present in 96.1% of FAI hips (123 of 128) and only 37.5% of control hips (9 of 24) ( p < 0.05). The ratio of PI in the FAI group was significantly higher (approximately 10%) than in the control group ( p < 0.05). The evaluation of sclerotic lesions may be used as a supplement to aid in the diagnosis of FAI.

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Femoroacetabular Impingement Patients With Decreased Femoral Version Have Different Impingement Locations and Intra- and Extraarticular Anterior Subspine FAI on 3D-CT–Based Impingement Simulation: Implications for Hip Arthroscopy

The American Journal of Sports Medicine ◽

10.1177/0363546519873666 ◽

2019 ◽

Vol 47 (13) ◽

pp. 3120-3132 ◽

Cited By ~ 11

Author(s):

Till D. Lerch ◽

Adam Boschung ◽

Inga A.S. Todorski ◽

Simon D. Steppacher ◽

Florian Schmaranzer ◽

...

Keyword(s):

Range Of Motion ◽

Internal Rotation ◽

Femoroacetabular Impingement ◽

Hip Arthroscopy ◽

Control Group ◽

Level Of Evidence ◽

Cross Sectional ◽

Hip Impingement ◽

Femoral Version ◽

Asymptomatic Control

Background: It remains unclear whether decreased femoral version (FV) causes anterior intra- or extra-articular femoroacetabular impingement (FAI). Therefore, we evaluated symptomatic hips with decreased FV, with and without cam and pincer FAI, by using computed tomography (CT)–based virtual 3-dimensional (3D) impingement simulation and compared this group with patients with normal FV and with asymptomatic hips. Purpose: To investigate (1) the osseous range of motion, (2) the osseous femoral and acetabular impingement zones, and (3) whether hip impingement is extra- or intra-articular in symptomatic hips with FAI. Study Design: Cross-sectional study; Level of evidence, 3. Methods: An institutional review board–approved, retrospective comparative analysis was performed on a total of 84 hips in 68 participants. Of these, 37 hips in 24 symptomatic patients with FAI had decreased FV. These hips were compared with 21 hips of 18 symptomatic patients with anterior FAI with normal FV (10°-25°) and 26 asymptomatic hips with no FAI and normal FV. All patients with FAI were symptomatic and had anterior hip pain and a positive anterior impingement test. They underwent pelvic CT scans to measure FV. Decreased FV was defined as FV less than 5°. The 37 hips with decreased FV presented both with and without cam and pincer FAI. All 84 hips were evaluated by use of CT-based 3D models and a validated 3D range of motion and impingement simulation. Asymptomatic hips were contralateral normal hips imaged in patients undergoing total hip arthroplasty. Results: Hips with FAI combined with decreased FV had a significantly ( P < .001) lower mean flexion (114°± 8° vs 125°± 13°) and internal rotation (IR) at 90° of flexion (18°± 6° vs 32°± 9°, P < .001) compared with the asymptomatic control group. Symptomatic patients with FAI and normal FV had flexion of 120°± 16° and IR at 90° of flexion of 23°± 15°. In a subgroup analysis, we found a significantly ( P < .001) lower IR in 90° of flexion in hips with FV less than 5° combined with mixed-type FAI compared with hips with FV less than 5° without a cam- or pincer-type deformity. The maximal acetabular impingement zone for hips with decreased FV was located at the 2-o’clock position and ranged from 1 to 3 o’clock. In hips with decreased FV, most of the impingement locations were intra-articular but 32% of hips had combined intra- and extra-articular FAI in internal rotation in 90° of flexion. During the flexion-adduction-IR test performed in 10° and 20° of adduction, extra-articular subspine FAI had significantly ( P < .001) higher prevalence (68% and 84%) in hips with decreased FV compared with normal hips. Conclusion: Hips with FAI and decreased FV had less flexion and internal rotation in 90° of flexion compared with the asymptomatic control group. The majority of hip impingement due to low FV was intra-articular, but one-third of samples had combined intra- and extra-articular subspine FAI. Anterior extra- and intra-articular hip impingement can be present in patients who have FAI with decreased FV. This could be important for patients undergoing hip arthroscopy.

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Open MRI assessment of anterior femoroacetabular clearance in active and passive impingement-provoking postures

Bone & Joint Open ◽

10.1302/2633-1462.211.bjo-2021-0143 ◽

2021 ◽

Vol 2 (11) ◽

pp. 988-996

Author(s):

Maryam Mohtajeb ◽

Jolanda Cibere ◽

Michelle Mony ◽

Honglin Zhang ◽

Emily Sullivan ◽

...

Keyword(s):

Femoral Head ◽

Internal Rotation ◽

Femoroacetabular Impingement ◽

Hip Osteoarthritis ◽

Population Based ◽

Joint Degeneration ◽

Open Mri ◽

Hip Flexion ◽

Head Neck ◽

Acetabular Rim

Aims Cam and pincer morphologies are potential precursors to hip osteoarthritis and important contributors to non-arthritic hip pain. However, only some hips with these pathomorphologies develop symptoms and joint degeneration, and it is not clear why. Anterior impingement between the femoral head-neck contour and acetabular rim in positions of hip flexion combined with rotation is a proposed pathomechanism in these hips, but this has not been studied in active postures. Our aim was to assess the anterior impingement pathomechanism in both active and passive postures with high hip flexion that are thought to provoke impingement. Methods We recruited nine participants with cam and/or pincer morphologies and with pain, 13 participants with cam and/or pincer morphologies and without pain, and 11 controls from a population-based cohort. We scanned hips in active squatting and passive sitting flexion, adduction, and internal rotation using open MRI and quantified anterior femoroacetabular clearance using the β angle. Results In squatting, we found significantly decreased anterior femoroacetabular clearance in painful hips with cam and/or pincer morphologies (mean -11.3° (SD 19.2°)) compared to pain-free hips with cam and/or pincer morphologies (mean 8.5° (SD 14.6°); p = 0.022) and controls (mean 18.6° (SD 8.5°); p < 0.001). In sitting flexion, adduction, and internal rotation, we found significantly decreased anterior clearance in both painful (mean -15.2° (SD 15.3°); p = 0.002) and painfree hips (mean -4.7° (SD 13°); p = 0.010) with cam and/pincer morphologies compared to the controls (mean 7.1° (SD 5.9°)). Conclusion Our results support the anterior femoroacetabular impingement pathomechanism in hips with cam and/or pincer morphologies and highlight the effect of posture on this pathomechanism. Cite this article: Bone Jt Open 2021;2(11):988–996.

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Hip Internal Rotation Is Correlated to Radiographic Findings of Cam Femoroacetabular Impingement in Collegiate Football Players

Arthroscopy The Journal of Arthroscopic and Related Surgery ◽

10.1016/j.arthro.2012.04.153 ◽

2012 ◽

Vol 28 (11) ◽

pp. 1661-1670 ◽

Cited By ~ 35

Author(s):

Ashley L. Kapron ◽

Andrew E. Anderson ◽

Christopher L. Peters ◽

Lee G. Phillips ◽

Gregory J. Stoddard ◽

...

Keyword(s):

Internal Rotation ◽

Femoroacetabular Impingement ◽

Football Players ◽

Radiographic Findings ◽

Hip Internal Rotation ◽

Collegiate Football

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Prevalence of radiographic markers of femoroacetabular impingement in asymptomatic adults

Revista do Colégio Brasileiro de Cirurgiões ◽

10.1590/s0100-69912014000100008 ◽

2014 ◽

Vol 41 (1) ◽

pp. 36-42 ◽

Cited By ~ 15

Author(s):

Rodrigo Benedet Scheidt ◽

Carlos Roberto Galia ◽

Cristiano Valter Diesel ◽

Ricardo Rosito ◽

Carlos Alberto De Souza Macedo

Keyword(s):

Internal Rotation ◽

Femoroacetabular Impingement ◽

Alpha Angle ◽

Posterior Wall ◽

Cross Sectional Study ◽

Cross Sectional ◽

Radiographic Findings ◽

Asymptomatic Patients ◽

Asymptomatic Volunteers ◽

Hip Internal Rotation

OBJECTIVE: to determine the prevalence of radiographic signs of femoroacetabular impingement (FAI) in asymptomatic adults and correlate them with data from physical examinations. METHODS: We conducted a cross-sectional study with 82 asymptomatic volunteers, 164 hips, between 40 and 60 years of age, selected by convenience. They were submitted to anamnesis and clinical examination of the hip, anteroposterior (AP) pelvis radiographs with three incidences, Dunn 45° and Lequesne false profile of each hip, to measure the variables. We measured the alpha angle, anterior offset of the femoral neck, cervical diaphyseal angle, CE angle of Wiberg, acetabular index, Sharp angle, and the crossing, ischial spine and posterior wall signs. RESULTS: our sample consisted of 66% women, mean age of 50.4 years. The average alpha angle was 45.10°, SD=8.6. One quarter of the hips showed alpha angle greater than or equal to 50°; among men the prevalence was 34%, and among women, 11%. We found indicative radiographic signs of femoroacetabular impingement in 42.6% of hips, whether femoral or acetabular, and the increased alpha angle was related to the decrease in hip internal rotation (p<0.001). CONCLUSION: the radiographic findings of femoroacetabular impingement in asymptomatic patients were frequent in the studied sample. The increase in alpha angle was associated with decreased internal rotation.

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Hip joint range of motion is restricted by pain rather than mechanical impingement in individuals with femoroacetabular impingement syndrome

Archives of Orthopaedic and Trauma Surgery ◽

10.1007/s00402-021-04185-4 ◽

2021 ◽

Author(s):

Josefine E. Naili ◽

Anders Stålman ◽

Anders Valentin ◽

Mikael Skorpil ◽

Lars Weidenhielm

Keyword(s):

Range Of Motion ◽

Internal Rotation ◽

Motion Analysis ◽

Femoroacetabular Impingement ◽

Motion Simulation ◽

3D Motion ◽

3D Motion Analysis ◽

Femoroacetabular Impingement Syndrome ◽

Hip Rotation ◽

Linear Regressions

Abstract Introduction Discerning whether range of motion (ROM) is restricted by morphology or other pain sources is challenging in patients with femoroacetabular impingement syndrome (FAIS). Computed tomography (CT) motion simulation provides a hypothetical ROM based on morphology. This study aimed to explore associations between ROM measured using CT motion simulation and maximum passive ROM measured clinically using three dimensional (3D) motion analysis in patients with FAIS, prior to and post arthroscopic hip surgery. Materials and methods Eight males with FAIS (in total 12 hip joints) were included in this explorative feasibility study. Participants were examined using CT according to a low-dose protocol prior to and 7-months post arthroscopic surgery. Software was used to simulate at which ROM the impingement would occur. With the hip in 90 degrees’ flexion, maximum passive range of internal hip rotation, and maximum passive internal hip rotation coupled with adduction was examined clinically using 3D motion analysis pre- and postoperatively. Spearman rank correlation coefficients and linear regressions examined associations between methods. Results Preoperatively, the correlation between maximum internal hip rotation measured using CT motion simulation and 3D motion analysis was strong (r = 0.71, p = 0.009). Linear regressions demonstrated that maximal internal rotation measured using CT motion simulation was predominantly larger than when measured using 3D motion analysis. Postoperatively, and when maximum internal rotation was coupled with adduction, no correlations were found between the two methods. Conclusions The hypothetical morphology restricted ROM is larger than clinically assessed pain restricted ROM, both prior to and post hip arthroscopy. These findings suggest that ROM is restricted by pain rather than mechanical, morphology-based impingement in individuals with FAIS.

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Hip Joint Torsional Loading Before and After Cam Femoroacetabular Impingement Surgery

The American Journal of Sports Medicine ◽

10.1177/0363546518815159 ◽

2018 ◽

Vol 47 (2) ◽

pp. 420-430 ◽

Cited By ~ 6

Author(s):

K.C. Geoffrey Ng ◽

Hadi El Daou ◽

Marcus J.K. Bankes ◽

Ferdinando Rodriguez y Baena ◽

Jonathan R.T. Jeffers

Keyword(s):

Internal Rotation ◽

Femoroacetabular Impingement ◽

Hip Joint ◽

External Rotation ◽

Joint Mechanics ◽

External Torque ◽

Cam Deformity ◽

Capsular Repair ◽

Applied Torque ◽

Cam Resection

Background: Surgical management of cam femoroacetabular impingement (FAI) aims to preserve the native hip and restore joint function, although it is unclear how the capsulotomy, cam deformity, and capsular repair influence joint mechanics to balance functional mobility. Purpose: 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 on passive range of motion and resistance of applied torque. Study Design: Descriptive laboratory study. Methods: Twelve cadaveric hips with cam deformities 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), and (6) flexion-abduction and external rotation. Then the robot performed applicable internal and external rotations, recording the neutral path of motion until a 5-N·m of 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 N·m of internal and external torque again after each stage. 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: Regarding changes in motion, external rotation increased substantially after capsulotomies, but internal rotation only further increased at flexion 90° (change +32%, P = .001, d = 0.58) and FADIR (change +33%, P < .001, d = 0.51) after cam resections. Capsular repair provided marginal restraint for internal rotation but restrained the external rotation compared with the capsulotomy stage. Regarding changes in torque, both internal and external torque resistance decreased after capsulotomy. Compared with the capsulotomy stage, cam resection further reduced internal torque resistance during flexion 90° (change −45%, P < .001, d = 0.98) and FADIR (change −37%, P = .003, d = 1.0), where the cam deformity accounted for 21% of the intact hip’s torsional resistance in flexion 90° and 27% in FADIR. Conclusion: Although the capsule played a predominant role in joint constraint, the cam deformity provided 21% to 27% of the intact hip’s resistance to torsional load in flexion and internal rotation. Resecting the cam deformity would remove this loading on the chondrolabral junction. Clinical Relevance: These findings are the first to quantify the contribution of the cam deformity to resisting hip joint torsional loads and thus quantify the reduced loading on the chondrolabral complex that can be achieved after cam resection.

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