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Imaging & Biomechanics

Hip imaging and biomechanics for FAI, focusing on the transition from 2D radiographs to 3D modeling for assessing osseous conflict and labral pathology.

Overview

Conventional radiographs remain critical for the initial evaluation of hip pathology [1], while MRI provides superior soft-tissue contrast for both intra-articular and extra-articular assessment [1]. In the context of total joint replacements, imaging is an essential component of the work-up within a specific clinical context [13]. For metal-on-metal hip resurfacings, the choice of imaging modality for general pseudotumour assessment depends on local financial constraints and expertise, though combined imaging is recommended for patients requiring revision [23].

Advanced imaging plays a nuanced role in specific scenarios. Magnetic Resonance Imaging may underestimate hip femoral version compared to Computed Tomography, yet both modalities can be optimized using 3-dimensional imaging [12]. Three-dimensional computed tomography mapping of both column acetabular fractures may yield insight relevant to surgical approaches, reduction strategies, fixation strategies, and implant design [49]. While cross-table lateral radiographs provide acceptable assessment of general component position, they have limited utility for precise analysis in research or determining the cause of implant failure, with acetabular component anteversion measurements varying by more than 10° in 20% of patients [17].

Emerging technologies and specific clinical applications require careful interpretation. MRI offers the potential to identify patients at higher risk of implant dislocation after posterior approach total hip arthroplasty [14]. A specific approach for aseptic loosening of the acetabular cup after cementless total hip arthroplasty can accurately determine the specific location of prosthetic loosening without relying on postoperative baseline or serial follow-up radiographs [3]. Understanding the current evidence and appropriate indications of emerging technologies in orthopaedic trauma is of critical importance for their utilization [26].

Anatomy & Pathophysiology

Conventional radiographs remain critical for the initial evaluation of hip pathology [1], while MRI provides superior soft-tissue contrast for intra- and extra-articular assessment [1]. Advanced imaging modalities further refine surgical planning: reliable 3D analysis of the hip joint using deep learning-based MRI can be indicative for surgical decision-making in patients with hip deformities [8], and the proposed method for assessing acetabular volume and orientation in computed tomography spatial reconstruction is a new, reliable diagnostic tool for normal and pathologic hip joints [9]. Simultaneous multi-slice MR imaging at 3 T reduces acquisition times while maintaining image quality comparable to conventional imaging for morphological evaluations of hip joint disorders [18]. Automated volumetric cartilage quantification provides a tool for temporal analysis of cartilage thickness to support surgical intervention in hip preservation [53], and an AI model performed adequately in predicting hip osteoarthritis progression using plain radiographs and clinical data [58].

Osseous Morphology: Extensive knowledge of anatomy and normal function of the hip is critical to identifying pathologies and developing successful treatment strategies [4]. In young adults with hip pain and labral tears, women have smaller alpha angles [51] and hips that are generally more anteverted [51], contributing to the higher prevalence of pincer-type femoroacetabular impingement observed in women [61]. The %FHC determined by CG strongly correlated with segmented acetabular subtended angles and thus more likely reflected true values [52]. Dysplastic hips have decreased iliofemoral ligament thickness on coronal sequences in magnetic resonance imaging [56].

Ligamentous & Capsular Integrity: Hip microinstability is characterized by abnormal femoral head micromotion within the acetabulum, leading to cartilage damage and osteoarthritis [48], and is often associated with acetabular dysplasia or femoroacetabular impingement syndrome [48]. Further investigation is needed to evaluate potential implications with hip instability given the thinner hip capsule demonstrated in dysplastic hips [56]. A reproducible method of measuring hip joint reaction force using a cartilage relaxation technique preserves all periarticular stabilizing soft tissue structures [63].

Pathophysiology & Outcomes: A more accurate set of definitions must be developed to allow for more accurate diagnosis of early hip disease [7]. Normalized joint biomechanics or regressive postoperative activation of the inflammatory cascade may explain the recovery of the dGEMRIC index 3 years after surgical FAI correction [19]. Segmental electrical bioimpedance equipment can detect differences between limbs affected and unaffected by hip osteoarthritis [59]. Increasing symptoms and decreased function related to degenerative hip disease may occur fifteen to twenty years after Colonna arthroplasty with concomitant femoral shortening and rotational osteotomy [60]. The performance of the automated system for radiological measurements is sufficient for application in clinical practice to support the assessment of hip migration based on RMP in children with cerebral palsy [57].

Classification

Imaging Modalities: Conventional radiographs remain critical for the initial evaluation of hip pathology [1]. MRI provides superior soft-tissue contrast for both intra-articular [1] and extra-articular assessment of hip pathology [1]. Diagnostic accuracy of three-dimensional dynamic analysis of CT scans is comparable to radiographs for detecting femoroacetabular impingement (FAI) caused by cam or pincer type morphology [36]. 3D-CT scans are reliable enough in the classification of acetabular fractures [47], and plain radiographs could be omitted in this classification to avoid radiation exposure [47] or reduce cost for patients who sustain acetabular fractures [47]. A proposed method serves as a new, reliable diagnostic tool for assessing the acetabula in both normal and pathologic hip joints [9].

Implant and Fracture Assessment: A specific approach can accurately determine the specific location of prosthetic loosening without relying on postoperative baseline radiographs or serial follow-up radiographs [3]. Imaging is one essential part in the work-up of patients with total joint replacements within a specific clinical context [13]. MRI offers the potential to identify patients with a higher risk of implant dislocation after posterior approach total hip arthroplasty [14].

Disease Characterization: A proposed deep learning model exhibited high accuracy in segmenting and grading necrotic lesions according to the Steinberg classification using MRI [50]. A reliable 3D analysis of the hip joint can be indicative for surgical decision-making in patients with hip deformities [8].

Other Considerations: Extensive knowledge of anatomy and normal function of the hip is critical to identifying pathologies [4] and developing successful treatment strategies [4]. Clinical assessment accurately determined the existence of intra-articular abnormality in hip arthroscopy patients [5] but was poor at defining the nature of intra-articular abnormality in hip arthroscopy patients [5]. A more accurate set of definitions must be developed to allow for more accurate diagnosis of early hip disease [7].

Clinical Presentation

Conventional radiographs remain critical for the initial evaluation of hip pathology [1]. Evaluation of leg length change from radiographs is considered sufficient provided the radiographs are taken accurately [11]. A specific approach can accurately determine the location of prosthetic loosening without relying on postoperative baseline or serial follow-up radiographs [3]. MRI provides superior soft-tissue contrast for intra- and extra-articular assessment of hip pathology [1]. A novel hip flexion scanning position for MRI can improve the diagnostics of proximal hamstring tendinopathy, especially if an athlete or active patient with gluteal area pain has normal or minimal MRI findings in the standard position [30].

Imaging Modalities: Ultrasonography is a safe, noninvasive method that is more sensitive than clinical examination for detecting hip abnormalities [20]. This modality can resolve the dilemma of immediate versus delayed treatment for unstable hips [20]. In patients with a normal MRI without contrast and a positive response to an intra-articular injection who failed conservative management, there is a 98% chance of intra-articular hip pathology being discovered on hip arthroscopy [21].

Clinical Assessment: Extensive knowledge of anatomy and normal function of the hip is critical to identifying pathologies [4]. Clinical assessment accurately determined the existence of intra-articular abnormality in hip arthroscopy patients [5], yet it was poor at defining the nature of intra-articular abnormalities in these patients [5]. Clinical decision making should carefully analyze the association of patient history and physical examination with radiographic imaging [6]. A more accurate set of definitions must be developed to allow for more accurate diagnosis of early hip disease [7].

Pathology Patterns: Pathologic changes seen on MRI were symptomatic in less than two thirds of elite female ballet dancers [32]. The most common finding in the symptomatic hips of younger retired National Football League players was chondral lesions [33]. Labral tears were the second most common finding in the symptomatic hips of younger retired National Football League players [33]. The proposed method is a new, reliable diagnostic tool for assessing acetabular volume and orientation in both normal and pathologic hip joints [9].

Investigations

Plain radiography: Conventional radiographs remain critical for the initial evaluation of hip pathology [1]. A highly standardized radiological technique is required for the precise measurement of femoral stem version on anteroposterior radiographs after total hip arthroplasty [24]. Clinical decision making should carefully analyze the association of patient history and physical examination with radiographic imaging [6].

MRI: MRI provides superior soft-tissue contrast for both intra-articular [1] and extra-articular assessment of hip pathology [1]. MRI may underestimate hip femoral version compared to computed tomography scans [12], though both MRI and CT may be optimized using 3-dimensional imaging [12]. Simultaneous multi-slice (SMS) MR imaging at 3 T significantly reduces acquisition times while maintaining image quality comparable to conventional imaging [18] and can be applied to morphological evaluations of hip joint disorders without significantly increasing specific absorption rate (SAR) [18]. MRI-based 3-dimensional models of the pelvis and hip using machine learning for automatic bone segmentation are feasible with routine MRI and short image acquisition times [25]. There was not a significant difference between different MRI modalities regarding the measurement of hip labral width compared with intraoperative assessment [34], and labral width can be reliably measured using magnetic resonance imaging [42]. Gadolinium intra-articular contrast MRI is not required for every patient undergoing hip arthroscopy [45].

CT: CT has higher interobserver reliability than MRI for measuring femoral anteversion [40]. Labral width can be reliably measured using computed tomography [42]. Contrast MRI plus CT with 3-dimensional reconstruction are essential for patients requiring revision hip arthroscopy [45].

Fluoroscopy: With careful attention to technique, the fluoroscopically simulated Dunn view can measure femoral version with acceptable accuracy [37]. The fluoroscopically simulated Dunn view obviates the need for repeat 3-dimensional imaging for patients who already have an MRI scan without version analysis [37].

Other Considerations: Extensive knowledge of hip anatomy and normal function is critical to identifying pathologies [4] and developing successful treatment strategies [4]. Clinical assessment accurately determines the existence of intra-articular abnormality in hip arthroscopy patients [5] but is poor at defining the nature of intra-articular abnormality in hip arthroscopy patients [5]. Diagnosis of femoral anteversion should not rely exclusively on physical examination or radiologic criteria [40]. An approach to determining prosthetic loosening can accurately identify the specific location of loosening without relying on postoperative baseline radiographs or serial follow-up radiographs [3]. MRI offers the potential to identify patients with a higher risk of implant dislocation after posterior approach total hip arthroplasty [14]. Larger alpha angles are appreciated on MRI/MRA radial and axial oblique views compared to radiographic views in patients with femoroacetabular impingement syndrome [38], and inclusion of MRI/MRA alpha angle measurements is supported to properly identify deformity in femoroacetabular impingement syndrome [38]. A more accurate set of definitions must be developed to allow for more accurate diagnosis of early hip disease [7].

Treatment

Imaging & Biomechanics: Conventional radiographs remain critical for the initial evaluation of hip pathology [1], though MRI provides superior soft-tissue contrast for intra- and extra-articular assessment [1]. Ultrasonography is a safe, noninvasive method that is more sensitive than clinical examination for detecting hip abnormalities and can resolve the dilemma of immediate versus delayed treatment for unstable hips [20]. For patients with a normal MRI without contrast and a positive response to an intra-articular injection who failed conservative management, there is a 98% chance of intra-articular hip pathology being discovered on hip arthroscopy [21]. Extensive knowledge of anatomy and normal function of the hip is critical to identifying pathologies and developing successful treatment strategies [4].

Diagnostic Modalities: The approach for determining prosthetic loosening does not rely on postoperative baseline radiographs or serial follow-up radiographs but can accurately determine the specific location of prosthetic loosening [3]. Imaging is one essential part in the work-up of patients with total joint replacements within a specific clinical context [13]. Cross-table lateral radiographs provide acceptable assessment of general component position but have limited use for precise analysis in research, outcome reporting, or determination of cause of implant failure, with variation in acetabular component anteversion measurements exceeding 10° in 20% of patients [17]. A highly standardised radiological technique is required for the precise measurement of femoral stem version on anteroposterior radiographs of the hip after total hip arthroplasty [24]. CT is not sensitive in the detection of intra-articular bodies in all cases following traumatic hip dislocation [43]. The choice of imaging modality for general assessment of pseudotumours in metal-on-metal hip resurfacings depends on local financial constraints and expertise, and combined imaging is recommended for patients requiring revision of metal-on-metal hip resurfacings [23]. Simultaneous multi-slice MR imaging at 3 T may be applied to morphological evaluations of hip joint disorders without significantly increasing SAR and has significantly lower acquisition times while maintaining similar image quality to conventional imaging [18]. Future studies are warranted to evaluate the use of CT imaging with 3D planning to determine the most practical and accurate imaging modality [12].

Surgical Indications & Outcomes: Surgical management is indicated for progressive, painful, unilateral deformity or leg-length discrepancy in coxa vara in childhood, whereas moderate nonprogressive deformity often does not require surgery [39]. Operative management for Dupuytren's contracture is appropriate when metacarpophalangeal or proxacal interphalangeal joint contracture exceeds 30 degrees [67]. Treatment options for hallux rigidus and osteoarthrosis of the first metatarsophalangeal joint range from non-operative measures to various surgical procedures including cheilectomy, arthroplasty, and arthrodesis, with selection depending on disease stage and patient factors [55]. AMIC is an effective and safe method of treating symptomatic full-thickness chondral defects of the knee in appropriately selected cases [15]. Double semitendinosus anterior cruciate ligament reconstruction is efficient in restoring satisfactory stability for most patients and stabilizes the evolution of degenerative lesions as shown by standing X-ray [16]. At 2 years after ACL reconstruction with tibialis anterior allografts, the subject group displayed satisfactory functional outcomes [44].

Patient Selection & Biomechanics: Female gender is associated with ease of hip distractability at time of hip arthroscopy, as is a decreased lateral center edge angle and a positive hyperextension–external rotation test; these findings may allow pre-operative identification of hip instability patients and aid in pre-operative counseling, risk stratification and capsular management planning [64]. Hip labral width less than 1 SD below the mean measured via preoperative MRI was associated with significantly worse functional outcomes after arthroscopic labral repair and treatment of femoroacetabular impingement [35]. Quantitative assessment of femoral head revascularization using serial perfusion MRI can help determine the timing for safe weight-bearing and evaluate healing responses to treatments like multiple epiphyseal drilling [41]. Improved histology was correlated with improved final construct strength at the 12-week time point in tendon-to-bone interface healing using an interposition bioresorbable scaffold [10]. Understanding the current evidence and appropriate indications of emerging technologies in orthopaedic trauma is of critical importance for their utilization [26]. Further prospective studies are necessary to show the safety and efficacy of arthroscopy following traumatic hip dislocation [43].

Complications

Imaging & Biomechanics: Conventional radiographs: Remain critical for the initial evaluation of hip pathology [1] and are considered sufficient for evaluating leg length change if taken accurately [11]. X-rays taken immediately after total hip arthroplasty rarely reveal unknown complications [66]. MRI: Provides superior soft-tissue contrast for intra- and extra-articular assessment of hip pathology [1]. Close radiological follow-up is recommended for soft-tissue lesions around metal-on-metal total hip arthroplasties, particularly in high-risk groups [28]. Clinical Assessment: Accurately determines the existence of intra-articular abnormality but is poor at defining its nature [5]. Clinical decision making should carefully analyze the association of patient history and physical examination with radiographic imaging [6]. Component Position & Analysis: Cross-table lateral (CL) imaging provides acceptable assessment of general component position but has limited use for precise analysis in research, outcome reporting, or determination of cause of implant failure due to variation exceeding 10° in 20% of patients [17]. Without objective 3-dimensional measurements, it is impossible to fully understand the cohort being studied or compare results of interventions regarding hip acetabular retroversion [29]. Biomechanics & Long-term Outcomes: High impact forces in long-distance running are well tolerated and do not demonstrate changes on MR images [22]. Finite element analysis based on mid-term radiological evaluation may be helpful to predict the influence of long-term stress shielding more precisely [27]. Despite major primary complications and a high incidence of radiographic signs of degenerative changes after 8.8 years, mainly good clinical results were achieved with Judet's bipolar prosthesis [54].

Other Considerations: The evidence base for this section focuses on diagnostic utility, biomechanical tolerance, and radiographic limitations rather than specific complication incidence rates or management algorithms for infection, loosening, or instability.

Recovery

Light activity (weeks): Clinical assessment accurately determines the existence of intra-articular abnormality but is poor at defining its nature [5]. Clinical decision making should carefully analyze the association of patient history and physical examination with radiographic imaging [6]. Evaluation of leg length change from radiographs is considered sufficient if radiographs can be taken accurately [11].

Full activity (months): Double semitendinosus anterior cruciate ligament reconstruction restores satisfactory stability for most patients and stabilizes the evolution of degenerative lesions as shown by standing X-ray [16]. High impact forces in long-distance running are well tolerated and do not demonstrate changes on MR images [22]. Autologous Matrix-Induced Chondrogenesis (AMIC) is an effective and safe method for treating symptomatic full-thickness chondral defects of the knee in appropriately selected cases [15].

Complete recovery / outcome plateau (months): Improved histology at the tendon-to-bone interface was correlated with improved final construct strength at the 12-week time point [10]. The recovery of the dGEMRIC index 3 years after surgical femoroacetabular impingement (FAI) correction may be due to normalized joint biomechanics or regressive postoperative activation of the inflammatory cascade after intra-articular surgery [19]. There was no significant progression of acetabular cartilage degeneration as measured by structural collagen organization and integrity on T2 mapping from pre-operative imaging to the time of two-year follow-up following hip arthroscopy for femoroacetabular impingement [62]. Ten years postoperatively, measured periacetabular cortical and cancellous bone density changes had no influence on the good clinical and radiographic performance of a press-fit cup [65].

Rehabilitation protocol: The specific location of prosthetic loosening can be accurately determined without relying on postoperative baseline radiographs or serial follow-up radiographs [3]. Close radiological follow-up is recommended for patients with metal-on-metal total hip arthroplasties, particularly in high-risk groups [28]. Diagnosis of hip acetabular retroversion requires 3-dimensional imaging to fully understand the cohort being studied or compare results of interventions [29]. Magnetic Resonance Imaging-based 3-dimensional models of the pelvis and hip using machine learning for automatic bone segmentation in a dynamic hip impingement simulation are feasible with routine MRI and a short image acquisition time [25]. Finite element analysis based on mid-term radiological evaluation may be helpful to predict the influence of long-term stress shielding more precisely [27]. Low trabecular bone density at the site of the hip was associated with the duration of disease progression and degree of hip involvement in ankylosing spondylitis patients with hip involvement [68].

Key Evidence

  • [L4] This approach does not rely on postoperative baseline radiographs or serial follow-up radiographs and can accurately determine the specific location of prosthetic loosening. (10.1186/s12891-025-08607-x)
  • [L4] Clinical assessment accurately determined the existence of intra-articular abnormality but was poor at defining its nature. (10.1177/0363546504266480)
  • [L4] Clinical decision making should carefully analyze the association of patient history and physical examination with radiographic imaging. (10.1016/j.arthro.2014.11.042)
  • [L4] A more accurate set of definitions must be developed in order to allow for more accurate diagnosis of early hip disease. (10.1016/j.arth.2008.11.095)
  • [L4] This study paves the way for a more in-depth understanding of the underlying pathomechanism and a reliable 3D analysis of the hip joint that can be indicative for surgical decision-making in patients with hip deformities. (10.1177/03635465251339758)
  • [L4] The proposed method is a new, reliable diagnostic tool for assessing the acetabula in both normal and pathologic hip joints. (10.1186/s12891-015-0503-8)
  • [L5] Improved histology was correlated with improved final construct strength at the 12-week time point. (10.1016/j.jse.2019.05.024)
  • [L4] Evaluation of leg length change from radiographs was considered sufficient if radiographs can be taken accurately. (10.1186/s12891-021-04906-1)
  • [L5] Future studies are warranted to evaluate the use of CT imaging with 3D planning to determine the most practical and accurate imaging modality. (10.1016/j.arthro.2024.01.011)
  • [L5] Imaging is one essential part in the work-up of patients with total joint replacements, within a specific clinical context. (10.1302/2058-5241.2.160058)
  • [L3] MRI offers the potential to identify patients with a higher risk of implant dislocation. (10.5435/jaaos-d-18-00655)
  • [L4] AMIC is an effective and safe method of treating symptomatic full-thickness chondral defects of the knee in appropriately selected cases. (10.1007/s00167-010-1042-3)
  • [L4] The study shows that the procedure is efficient in restoring a satisfactory stability for most patients and stabilises the evolution of the degenerative lesions as shown by standing X-ray. (10.1007/s001670050076)
  • [L3] Although CL imaging provides acceptable assessment of general component position, it has limited use for precise analysis in research, outcome reporting, or determination of cause of implant failure due to variation exceeding 10° in 20% of patients. (10.1016/j.arth.2011.03.039)
  • [L4] Based on its significantly lower acquisition times and the maintenance of similar image quality to conventional imaging, SMS may be applied to morphological evaluations of hip joint disorders without significantly increasing SAR. (10.1186/s12891-018-2342-x)
  • [L3] This may be due to normalized joint biomechanics or regressive postoperative activation of the inflammatory cascade after intra-articular surgery. (10.1177/03635465231167854)
  • [L4] Ultrasonography is a safe, noninvasive method that is more sensitive than clinical examination for detecting hip abnormalities and can resolve the dilemma of immediate versus delayed treatment for unstable hips. (10.2106/00004623-200007000-00012)
  • [L4] In patients with a normal MRI without contrast and a positive response to an intra-articular injection that failed conservative management, there is a 98% chance of intra-articular hip pathology being discovered on hip arthroscopy. (10.1186/s12891-017-1485-5)
  • [L4] Our results suggest that the high impact forces in long-distance running are well tolerated and subsequently do not demonstrate changes on MR images. (10.1177/0363546503258904)
  • [L3] The choice of modality for general assessment depends on local financial constraints and expertise, but combined imaging is recommended for patients requiring revision. (10.1302/0301-620x.98b1.36746)
  • [L3] However, a highly standardised radiological technique is required for its precise measurement. (10.1302/0301-620x.97b3.34618)
  • [L3] The method was feasible with routine MRI and a short image acquisition time. (10.1177/23259671251334138)
  • [L4] Finite element analysis based on mid-term radiological evaluation may be helpful to predict the influence of long-term stress shielding more precisely. (10.1186/s12891-016-1260-z)
  • [L3] Close radiological follow-up is recommended, particularly in high-risk groups. (10.1302/0301-620x.97b10.34131)
  • [L5] Without objective 3-dimensional measurements, it is impossible to fully understand the cohort being studied or compare results of interventions. (10.1016/j.arthro.2023.09.011)
  • [L3] This position can improve the diagnostics of PHT, especially if an athlete or an active patient with gluteal area pain has normal or minimal MRI findings in the standard position. (10.1177/23259671241265130)
  • [L4] Pathologic changes seen on MRI were symptomatic in less than two thirds of the dancers. (10.1016/j.arthro.2012.10.012)
  • [L4] The most common finding was chondral lesions, followed by labral tears. (10.1177/0363546514531551)
  • [L2] There was not a significant difference between different MRI modalities. (10.1016/j.arthro.2019.09.027)
  • [L4] Hip labral width less than 1 SD below the mean measured via preoperative MRI was associated with significantly worse functional outcomes after arthroscopic labral repair and treatment of femoroacetabular impingement. (10.1016/j.arthro.2020.08.006)
  • [L4] Diagnostic accuracy is comparable in three-dimensional dynamic analysis of CT scans and radiographs representing FAI caused by cam or pincer type morphology. (10.1186/s12891-020-3049-3)
  • [L2] With careful attention to technique, the fluoroscopically simulated Dunn view can be used to measure femoral version with acceptable accuracy and obviates the need for repeat 3-dimensional imaging for patients who already have an MRI scan without version analysis. (10.1016/j.arthro.2017.01.022)
  • [L2] Larger alpha angles were appreciated on MRI/MRA radial and axial oblique views compared to radiographic views supporting the inclusion of MRI/MRA alpha angle measurements to properly identify deformity. (10.1002/ksa.12446)
  • [L5] Surgical management is indicated for progressive, painful, unilateral deformity or leg-length discrepancy, while moderate nonprogressive deformity often does not require surgery. (10.5435/00124635-199803000-00003)
  • [L3] CT was found to have higher interobserver reliability than MRI, and diagnosis should not rely exclusively on either examination or radiologic criteria. (10.1016/j.arthro.2011.10.021)
  • [L3] This quantitative assessment can help determine the timing for safe weight-bearing and evaluate healing responses to treatments like multiple epiphyseal drilling. (10.2106/jbjs.15.01477)
  • [L4] Labral width can reliably be measured utilizing imaging techniques including magnetic resonance and computed tomography. (10.1007/s00167-020-06330-9)
  • [L4] CT is not sensitive in the detection of intra-articular bodies in all cases, and further prospective studies are necessary to show the safety and efficacy of arthroscopy. (10.1016/j.arthro.2017.08.295)
  • [L4] At 2 years after ACL reconstruction with tibialis anterior allografts, this subject group displayed satisfactory functional outcomes. (10.1007/s00167-003-0371-x)
  • [L5] Gadolinium intra-articular contrast magnetic resonance imaging is not required for every patient undergoing hip arthroscopy, but contrast magnetic resonance imaging plus computed tomography with 3-dimensional reconstruction are essential for patients requiring revision. (10.1016/j.arthro.2022.12.008)
  • [L5] Fractures of the fingers are better understood, indications for surgical treatment are more clearly defined, and operative techniques and implants for osteosynthesis are continuing to evolve and improve, though results vary according to fracture type, surgeon experience, and patient compliance. (10.1054/jhsb.2002.0889)
  • [L3] 3D-CT scans are reliable enough in the classification of acetabular fractures, and plain radiographs could be omitted to avoid radiation exposure as well as to reduce the cost for patients who sustain acetabular fractures. (10.1186/s12891-020-03441-9)
  • [L4] These results may help surgeons yield insight relevant to surgical approaches, reduction, fixation strategies, and implant design. (10.1186/s12891-019-2622-0)
  • [L4] The proposed deep learning model exhibited high accuracy in segmenting and grading necrotic lesions according to the Steinberg classification using MRI. (10.1016/j.arth.2025.05.126)
  • [L3] In young adults with hip pain and labral tears, women have smaller alpha angles and hips that are generally more anteverted. (10.1016/j.arthro.2012.07.008)
  • [L2] The %FHC determined by CG strongly correlated with segmented acetabular subtended angles and thus more likely reflected true values. (10.1177/03635465221109240)
  • [L4] Despite major primary complications and high incidence of radiographic signs of degenerative changes after 8.8 years, mainly good clinical results were achieved with Judet's bipolar prosthesis. (10.1016/j.jse.2010.05.022)
  • [L5] Treatment options range from non-operative measures to various surgical procedures including cheilectomy, arthroplasty, and arthrodesis, with selection depending on disease stage and patient factors. (10.2106/00004623-199806000-00015)
  • [L3] Further investigation is needed to evaluate any potential implications with hip instability, given the thinner hip capsule demonstrated in this study. (10.1016/j.arthro.2024.05.033)
  • [L4] The performance of the system is sufficient for application in clinical practice to support the assessment of hip migration based on RMP. (10.1302/0301-620x.107b1.bjj-2024-0894)
  • [L4] The proposed AI model performed adequately in predicting hip OA progression and may be clinically applicable with additional datasets and validation. (10.1186/s12891-024-08034-4)
  • [L4] The segmental electrical bioimpedance equipment can detect differences between limbs affected and unaffected by hip osteoarthritis. (10.1186/s12891-023-06541-4)
  • [L4] However, increasing symptoms and decreased function related to degenerative hip disease may occur fifteen to twenty years after the procedure. (10.2106/00004623-199701000-00009)
  • [L3] These morphological differences suggest that gender-specific acetabular morphology may contribute to the higher prevalence of pincer-type femoroacetabular impingement observed in women. (10.1016/j.arthro.2015.02.007)
  • [L3] There was no significant progression of acetabular cartilage degeneration as measured by structural collagen organization and integrity on T2 mapping from pre-operative imaging to the time of two year follow up. (10.1177/2325967116s00142)
  • [L5] This study describes and validates a reproducible method of measuring hip JRF that preserves all periarticular stabilizing soft tissue structures. (10.1177/2325967117s00409)
  • [L4] These findings may allow pre-operative identification of hip instability patients and aid in pre-operative counseling, risk stratification and capsular management planning. (10.1007/s00167-022-06925-4)
  • [L2] Ten years postoperatively, the measured periacetabular cortical and cancellous bone density changes had no influence on the good clinical and radiographic performance of the cup. (10.2106/jbjs.j.01097)
  • [L3] In total hip arthroplasty, X-rays taken immediately after surgery rarely reveal unknown complications. (10.1186/s42836-022-00148-1)
  • [L5] Operative management is appropriate when metacarpophalangeal or proximal interphalangeal joint contracture exceeds 30 degrees. (10.5435/00124635-199801000-00003)
  • [L3] The low trabecular bone density at the site of the hip was associated with the duration of disease progression and degree of hip involvement. (10.1186/s12891-021-04912-3)

References

[1] Chapter 58 Imaging of the Hip. 2019.

[2] Chapter 153 Basic Science. 2019.

[3] Imaging study of aseptic loosening of the acetabular cup after cementless total hip arthroplasty: a retrospective study. BMC Musculoskeletal Disorders. 2025. DOI: 10.1186/s12891-025-08607-x

[4] Chapter 34 Anatomy and Biomechanics, Evaluation, Clinical Examination, and Imaging of the Hip. 2020.

[5] Diagnostic Accuracy of Clinical Assessment, Magnetic Resonance Imaging, Magnetic Resonance Arthrography, and Intra-Articular Injection in Hip Arthroscopy Patients. The American Journal of Sports Medicine. 2004. DOI: 10.1177/0363546504266480

[6] Prevalence of Femoroacetabular Impingement Imaging Findings in Asymptomatic Volunteers: A Systematic Review. Arthroscopy. 2015. DOI: 10.1016/j.arthro.2014.11.042

[7] Reliability Of Radiographic Diagnoses In The Young Adult Hip: A Multicenter Study. The Journal of Arthroplasty. 2009. DOI: 10.1016/j.arth.2008.11.095

[8] Contribution of Labrum and Cartilage to Joint Surface in Different Hip Deformities: An Automatic Deep Learning–Based 3-Dimensional Magnetic Resonance Imaging Analysis. The American Journal of Sports Medicine. 2025. DOI: 10.1177/03635465251339758

[9] An accurate method of radiological assessment of acetabular volume and orientation in computed tomography spatial reconstruction. BMC Musculoskeletal Disorders. 2015. DOI: 10.1186/s12891-015-0503-8

[10] A prospective study comparing tendon-to-bone interface healing using an interposition bioresorbable scaffold with a vented anchor for primary rotator cuff repair in sheep. Journal of Shoulder and Elbow Surgery. 2020. DOI: 10.1016/j.jse.2019.05.024

[11] Accuracy of image-free navigation in intraoperative leg length change from total hip arthroplasty using evaluations from 2D and 3D measurements. BMC Musculoskeletal Disorders. 2021. DOI: 10.1186/s12891-021-04906-1

[12] Editorial Commentary: Magnetic Resonance Imaging May Underestimate Hip Femoral Version Versus Computed Tomography Scan: Both May Be Optimized Using 3‐Dimensional Imaging. Arthroscopy. 2024. DOI: 10.1016/j.arthro.2024.01.011

[13] Imaging in peri-prosthetic assessment: an orthopaedic perspective. EFORT Open Reviews. 2017. DOI: 10.1302/2058-5241.2.160058

[14] MRI Evaluation of Posterior Capsular Dehiscence After Posterior Approach Total Hip Arthroplasty. Journal of the American Academy of Orthopaedic Surgeons. 2019. DOI: 10.5435/jaaos-d-18-00655

[15] Mid‐term results of Autologous Matrix‐Induced Chondrogenesis for treatment of focal cartilage defects in the knee. Knee Surgery, Sports Traumatology, Arthroscopy. 2010. DOI: 10.1007/s00167-010-1042-3

[16] Double semitendinosus anterior cruciate ligament reconstruction: 10‐year results. Knee Surgery, Sports Traumatology, Arthroscopy. 1998. DOI: 10.1007/s001670050076

[17] The Reliability and Variation of Acetabular Component Anteversion Measurements From Cross-Table Lateral Radiographs. The Journal of Arthroplasty. 2011. DOI: 10.1016/j.arth.2011.03.039

[18] Simultaneous multi-slice MR imaging of the hip at 3 T to reduce acquisition times and maintain image quality. BMC Musculoskeletal Disorders. 2018. DOI: 10.1186/s12891-018-2342-x

[19] Does the dGEMRIC Index Recover 3 Years After Surgical FAI Correction and an Initial dGEMRIC Decrease at 1-Year Follow-up? A Controlled Prospective Study. The American Journal of Sports Medicine. 2023. DOI: 10.1177/03635465231167854

[20] Ultrasonography in Developmental Dysplasia of the Hip. The Journal of Bone and Joint Surgery-American Volume*. 2000. DOI: 10.2106/00004623-200007000-00012

[21] Arthroscopic findings of a diagnostic dilemma- hip pathology with normal imaging. BMC Musculoskeletal Disorders. 2017. DOI: 10.1186/s12891-017-1485-5

[22] MR Imaging of the Hip and Knee before and after Marathon Running. The American Journal of Sports Medicine. 2004. DOI: 10.1177/0363546503258904

[23] Which imaging modality is most effective for identifying pseudotumours in metal-on-metal hip resurfacings requiring revision. The Bone & Joint Journal. 2016. DOI: 10.1302/0301-620x.98b1.36746

[24] The validity of a novel radiological method for measuring femoral stem version on anteroposterior radiographs of the hip after total hip arthroplasty. The Bone & Joint Journal. 2015. DOI: 10.1302/0301-620x.97b3.34618

[25] Magnetic Resonance Imaging–Based 3-Dimensional Models of the Pelvis and Hip Using Machine Learning for Automatic Bone Segmentation in a Dynamic Hip Impingement Simulation. Orthopaedic Journal of Sports Medicine. 2025. DOI: 10.1177/23259671251334138

[26] Chapter 3 Emerging Technologies in Orthopaedic Trauma. 2021.

[27] Finite element analysis of cementless femoral stems based on mid- and long-term radiological evaluation. BMC Musculoskeletal Disorders. 2016. DOI: 10.1186/s12891-016-1260-z

[28] A longitudinal study of MARS MRI scanning of soft-tissue lesions around metal-on-metal total hip arthroplasties and disease progression. The Bone & Joint Journal. 2015. DOI: 10.1302/0301-620x.97b10.34131

[29] Editorial Commentary : Diagnosis of Hip Acetabular Retroversion Requires 3‐Dimensional Imaging. Arthroscopy. 2024. DOI: 10.1016/j.arthro.2023.09.011

[30] Magnetic Resonance Imaging With a Novel Hip Flexion Scanning Position for Diagnosing Proximal Hamstring Tendinopathy. Orthopaedic Journal of Sports Medicine. 2024. DOI: 10.1177/23259671241265130

[32] Correlation of Clinical and Magnetic Resonance Imaging Findings in Hips of Elite Female Ballet Dancers. Arthroscopy. 2013. DOI: 10.1016/j.arthro.2012.10.012

[33] Magnetic Resonance Imaging Findings in the Symptomatic Hips of Younger Retired National Football League Players. The American Journal of Sports Medicine. 2014. DOI: 10.1177/0363546514531551

[34] Validity of Magnetic Resonance Imaging Measurement of Hip Labral Width Compared With Intraoperative Assessment. Arthroscopy. 2019. DOI: 10.1016/j.arthro.2019.09.027

[35] Decreased Hip Labral Width Measured via Preoperative Magnetic Resonance Imaging Is Associated With Inferior Outcomes for Arthroscopic Labral Repair for Femoroacetabular Impingement. Arthroscopy. 2020. DOI: 10.1016/j.arthro.2020.08.006

[36] Diagnostic sensitivity and specificity of dynamic three-dimensional CT analysis in detection of cam and pincer type femoroacetabular impingement. BMC Musculoskeletal Disorders. 2020. DOI: 10.1186/s12891-020-3049-3

[37] Comparison of Intraoperative Fluoroscopic Dunn View With Magnetic Resonance Imaging to Determine Femoral Version. Arthroscopy. 2017. DOI: 10.1016/j.arthro.2017.01.022

[38] Significant systematic bias of alpha angles measured on MRI compared to various radiographic views in patients with femoroacetabular impingement syndrome. Knee Surgery, Sports Traumatology, Arthroscopy. 2024. DOI: 10.1002/ksa.12446

[39] Coxa Vara in Childhood: Evaluation and Management. Journal of the American Academy of Orthopaedic Surgeons. 1998. DOI: 10.5435/00124635-199803000-00003

[40] Femoral Anteversion in the Hip: Comparison of Measurement by Computed Tomography, Magnetic Resonance Imaging, and Physical Examination. Arthroscopy. 2012. DOI: 10.1016/j.arthro.2011.10.021

[41] Assessment of Femoral Head Revascularization in Legg-Calvé-Perthes Disease Using Serial Perfusion MRI. Journal of Bone and Joint Surgery. 2016. DOI: 10.2106/jbjs.15.01477

[42] The dimensions of the hip labrum can be reliably measured using magnetic resonance and computed tomography which can be used to develop a standardized definition of the hypoplastic labrum. Knee Surgery, Sports Traumatology, Arthroscopy. 2020. DOI: 10.1007/s00167-020-06330-9

[43] Arthroscopy After Traumatic Hip Dislocation: A Systematic Review of Intra‐articular Findings, Correlation With Magnetic Resonance Imaging and Computed Tomography, Treatments, and Outcomes. Arthroscopy. 2017. DOI: 10.1016/j.arthro.2017.08.295

[44] Two‐year outcomes following ACL reconstruction with allograft tibialis anterior tendons: a retrospective study. Knee Surgery, Sports Traumatology, Arthroscopy. 2003. DOI: 10.1007/s00167-003-0371-x

[45] Editorial Commentary : Gadolinium Intra‐Articular Contrast Magnetic Resonance Imaging Is Not Required for Every Patient Undergoing Hip Arthroscopy, but Contrast Magnetic Resonance Imaging Plus Computed Tomography With 3‐Dimensional Reconstruction Are Essential for Patients Requiring Revision. Arthroscopy. 2023. DOI: 10.1016/j.arthro.2022.12.008

[46] Treatment of Fractures of the Fingers. What’s New?. Journal of Hand Surgery. 2003. DOI: 10.1054/jhsb.2002.0889

[47] Evaluation of Judet view radiographs accuracy in classification of acetabular fractures compared with three-dimensional computerized tomographic scan: a retrospective study. BMC Musculoskeletal Disorders. 2020. DOI: 10.1186/s12891-020-03441-9

[48] Chapter 12 Hip Microinstability. 2019.

[49] Mapping of both column acetabular fractures with three-dimensional computed tomography and implications on surgical management. BMC Musculoskeletal Disorders. 2019. DOI: 10.1186/s12891-019-2622-0

[50] Development of a Deep Learning Model for the Volumetric Assessment of Osteonecrosis of the Femoral Head on Three-Dimensional Magnetic Resonance Imaging. The Journal of Arthroplasty. 2025. DOI: 10.1016/j.arth.2025.05.126

[51] Sex Differences of Hip Morphology in Young Adults With Hip Pain and Labral Tears. Arthroscopy. 2012. DOI: 10.1016/j.arthro.2012.07.008

[52] Comparison of Acetabular Measurements Between 2 Validated Software Programs Used in Hip Preservation Surgery. The American Journal of Sports Medicine. 2022. DOI: 10.1177/03635465221109240

[53] Evaluation_of_Automated_Volumetric_Cartilage_Quantification_for_Hip_Preservation_S0883540315007305. n.d..

[54] Mid- to long-term results after bipolar radial head arthroplasty. Journal of Shoulder and Elbow Surgery. 2010. DOI: 10.1016/j.jse.2010.05.022

[55] Current Concepts Review - Hallux Rigidus and Osteoarthrosis of the First Metatarsophalangeal Joint. The Journal of Bone & Joint Surgery*. 1998. DOI: 10.2106/00004623-199806000-00015

[56] Dysplastic Hips Have Decreased Iliofemoral Ligament Thickness on Coronal Sequences in Magnetic Resonance Imaging: A Matched Cohort Analysis. Arthroscopy: The Journal of Arthroscopic & Related Surgery. 2025. DOI: 10.1016/j.arthro.2024.05.033

[57] Automating radiological measurements of the hip in children with cerebral palsy. The Bone & Joint Journal. 2025. DOI: 10.1302/0301-620x.107b1.bjj-2024-0894

[58] Development and accuracy of an artificial intelligence model for predicting the progression of hip osteoarthritis using plain radiographs and clinical data: a retrospective study. BMC Musculoskeletal Disorders. 2024. DOI: 10.1186/s12891-024-08034-4

[59] Segmental bioelectrical impedance analysis can detect differences between the affected and non-affected limbs in individuals with hip osteoarthritis. BMC Musculoskeletal Disorders. 2023. DOI: 10.1186/s12891-023-06541-4

[60] Colonna Arthroplasty with Concomitant Femoral Shortening and Rotational Osteotomy. Long-Term Results. The Journal of Bone and Joint Surgery-American Volume*. 1997. DOI: 10.2106/00004623-199701000-00009

[61] A Computed Tomography Study of Gender Differences in Acetabular Version and Morphology: Implications for Femoroacetabular Impingement. Arthroscopy. 2015. DOI: 10.1016/j.arthro.2015.02.007

[62] Quantitative MRI Evaluation of Articular Cartilage Using T2 Mapping Following Hip Arthroscopy for Femoroacetabular Impingement. Orthopaedic Journal of Sports Medicine. 2016. DOI: 10.1177/2325967116s00142

[63] Radiographic Validation of a Non-invasive Method of Measuring Hip Joint Reaction Force using a Cartilage Relaxation Technique. Orthopaedic Journal of Sports Medicine. 2017. DOI: 10.1177/2325967117s00409

[64] Female gender, decreased lateral center edge angle and a positive hyperextension–external rotation test are associated with ease of hip distractability at time of hip arthroscopy. Knee Surgery, Sports Traumatology, Arthroscopy. 2022. DOI: 10.1007/s00167-022-06925-4

[65] Quantitative Computed Tomography-Assisted Osteodensitometry of the Pelvis After Press-Fit Cup Fixation. The Journal of Bone & Joint Surgery. 2011. DOI: 10.2106/jbjs.j.01097

[66] Are immediate postoperative X-Rays valuable in evaluating complications of primary total hip arthroplasty?. Arthroplasty. 2022. DOI: 10.1186/s42836-022-00148-1

[67] Dupuytren’s Contracture. Journal of the American Academy of Orthopaedic Surgeons. 1998. DOI: 10.5435/00124635-199801000-00003

[68] The correlation between volumetric bone mineral density and morphological parameters of the proximal femur and clinical outcomes in ankylosing spondylitis patients with hip involvement. BMC Musculoskeletal Disorders. 2022. DOI: 10.1186/s12891-021-04912-3

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