Imaging of femoroacetabular impingement-current concepts

Imaging Modalities in the Preoperative Assessment of Femoroacetabular Impingement and Hip Dysplasia: Determining Best Practices

» In the last decade, significant progress has been made in understanding hip pain, especially related to femoroacetabular impingement (FAI) and hip dysplasia (HD), which collectively affect over 20% of the population.» Preoperative imaging, including plain radiographs, computed tomography (CT), magnetic resonance imaging (MRI), and ultrasound (US), plays a pivotal role in diagnosing FAI and HD. Imaging precision, standardized techniques, and accurate interpretation are crucial for effective treatment planning.» The continual advancements in imaging techniques, especially seen in MRI (arthrograms, application of leg traction, and delayed gadolinium-enhanced MRI of cartilage), represent important strides in the precise assessment of pathology associated with FAI and HD.» By incorporating these advancements into routine imaging protocols, healthcare providers can ensure a comprehensive understanding of hip joint dynamics, enabling more accurate diagnosis and effective management strategies for patients with FAI and HD, ultimately leading to improved clinical outcomes.

Preoperative Paralabral Cysts Predict More Significant Chondral Damage but Not 2-Year Functional Outcomes Following Arthroscopic Labral Repair

PURPOSE

To investigate whether paralabral cysts identified incidentally on preoperative magnetic resonance imaging/arthrography predict 2-year functional outcomes after arthroscopic acetabular labral repair.

METHODS

Prospectively collected data for patients undergoing primary hip arthroscopy by a single surgeon from 2014 to 2020 were retrospectively reviewed. Included patients were ≥18 years and completed baseline patient-reported outcome measures (PROMs) with additional follow-up at 3, 6, 12, and 24 months. Exclusion criteria were labral debridement, hip dysplasia, advanced hip osteoarthritis (Tönnis > 1), or previous ipsilateral hip surgery. Patients were stratified based on the presence of paralabral cysts identified on magnetic resonance imaging/arthrography. Primary outcomes were International Hip Outcome Tool and modified Harris Hip Score. Secondary outcomes included other PROMs and the visual analog pain scale. Outcomes were compared between cohorts using linear mixed-effects models and Fisher's exact tests. Sensitivity analyses accounted for preoperative PROMs, nonlinear improvement trajectories, and relevant baseline characteristics.

RESULTS

Of the 182 included hips (47.8% female; mean ± standard deviation age, 36.9 ± 11.4), 30 (16.4%) had paralabral cysts. During the 2-year study period, there were no significant differences between patients with and without paralabral cysts in terms of International Hip Outcome Tool scores (weighted difference = 1.60; 95% confidence interval [CI], -5.09, 8.28; P = .64), modified Harris Hip Scores (weighted difference = 0.56; 95% CI, -4.16, 5.28; P = .82), or any secondary outcomes (except for HOS-Sports Subscale at 3 months [mean difference = -11.85; 95% CI, -22.85, -0.84; P = .035]). Furthermore, there were no significant differences in clinically meaningful outcomes (P > .05 for all), revision rates (P > .99), or conversion to total hip arthroplasty between cohorts (P > .99). These results held across all sensitivity analyses.

CONCLUSIONS

Although preoperative paralabral cysts were associated with worse cam impingement and more severe chondral damage observed intraoperatively, they did not predict 2-year functional outcomes or clinically meaningful improvements, suggesting that incidentally discovered paralabral cysts are not a contraindication for arthroscopic labral repair.

LEVEL OF EVIDENCE

Level III, retrospective cohort study.

Initial Assessment and Management of Select Musculoskeletal Injuries: A Team Physician Consensus Statement

ABSTRACT

Musculoskeletal injuries occur frequently in sport during practice, training, and competition. Injury assessment and management are common responsibilities for the team physician. Initial Assessment and Management of Musculoskeletal Injury-A Team Physician Consensus Statement is title 23 in a series of annual consensus documents written for the practicing team physician. This statement was developed by the Team Physician Consensus Conference, an annual project-based alliance of six major professional associations. The goal of this document is to help the team physician improve the care and treatment of the athlete by understanding the initial assessment and management of selected musculoskeletal injuries.

Initial Assessment and Management of Select Musculoskeletal Injuries: A Team Physician Consensus Statement

ABSTRACT

Musculoskeletal injuries occur frequently in sport during practice, training, and competition. Injury assessment and management are common responsibilities for the team physician. Initial Assessment and Management of Musculoskeletal Injury-A Team Physician Consensus Statement is title 23 in a series of annual consensus documents written for the practicing team physician. This statement was developed by the Team Physician Consensus Conference, an annual project-based alliance of six major professional associations. The goal of this document is to help the team physician improve the care and treatment of the athlete by understanding the initial assessment and management of selected musculoskeletal injuries.

Qualitative Research in Return to Sport: a Current Review of the Literature

PURPOSE OF REVIEW

Return to sport (RTS) is an important metric tied to patient satisfaction after receiving treatment for a sports-related injury. Recently, there has been an explosion of literature on RTS; yet a comprehensive review encompassing multiple injuries does not exist. Furthermore, RTS has historically been defined by quantitative measures that assess strength, function, and pain but little consideration has been given to psychologic factors nor has there been an open-ended forum for athletes to share with health care providers which factors they feel are most influential for RTS. This review also serves to heighten surgeons' awareness of underlying psychologic/psychosocial factors affecting RTS.

RECENT FINDINGS

Qualitative studies which employ open-ended questioning of athletes who have undergone surgical management of superior labral anterior-posterior (SLAP) tears, shoulder instability, ulnar collateral ligament (UCL) rupture, femoral acetabular impingement (FAI), and anterior cruciate ligament (ACL) tear demonstrate that fear of reinjury, lack of social support, and unrealistic expectations are all barriers to RTS. Qualitative studies give health care providers unique insight into the perspectives of their patients so that unmet postoperative needs can be addressed to facilitate RTS. Sports psychologists, coaches, athletic trainers, and physical therapists should create a positive environment to address these needs and provide optimal, holistic care to return athletes to the field safely. Though time consuming, further qualitative research is necessary to understand the unique factors affecting RTS in athletes.

The Association between Hip Joint Morphology and Posterior Wall Fracture: Analysis of Radiologic Parameters in Computed Tomography

Although numerous radiologic parameters of abnormal hip joint morphology are utilized in practice, studies on the relation of these parameters to acetabular fractures are limited. This study hypothesized that certain morphological features of hip joints are associated with acetabular posterior wall (PW) fracture patterns and aimed to identify morphological characteristics predictive of acetabular PW fracture. The records of 107 consecutive patients, who were diagnosed with acetabular fractures in a level I trauma center from August 2017 to April 2021, were initially reviewed. After excluding patients who lacked proper radiographic evaluation and had previous surgery or concomitant injury on the ipsilateral lower limb, a total of 99 patients were analyzed to investigate the morphological characteristics of the hip joint, measured in computed tomography, associated with acetabular posterior wall fracture. We included patient demographics, acetabular index (AI), sharp angle, acetabular depth-to-width ratio (AD/WR), center-edge angle (CEA), head-neck offset ratio (HNOR), acetabular head index (AHI), anterior acetabular sector angle (AASA), posterior acetabular sector angle (PASA), and acetabular version angle (AVA) in the univariate and multivariate analyses. The injury mechanism (p = 0.001) and AD/WR (p = 0.021) were predictors of PW fracture in the univariate analysis. In the multivariable analysis, injury mechanism (p = 0.011), AI (coefficient B = 0.320; Exp (B) = 1.377; p = 0.017), and AD/WR (coefficient B = 33.047; Exp (B) = 2.250 × 1014; p = 0.028) were significant predictors of PW fracture. This study highlights the importance of morphological factors, such as a larger AI and AD/WR, that may influence joint stress distribution, resulting in acetabular PW fracture. Understanding these pathomechanisms may protect the hip joint and prevent future injuries through the early identification and treatment of pathological conditions.

A radiomics approach to the diagnosis of femoroacetabular impingement

Introduction

Femoroacetabular Impingement (FAI) is a hip pathology characterized by impingement of the femoral head-neck junction against the acetabular rim, due to abnormalities in bone morphology. FAI is normally diagnosed by manual evaluation of morphologic features on magnetic resonance imaging (MRI). In this study, we assess, for the first time, the feasibility of using radiomics to detect FAI by automatically extracting quantitative features from images.

Material and methods

17 patients diagnosed with monolateral FAI underwent pre-surgical MR imaging, including a 3D Dixon sequence of the pelvis. An expert radiologist drew regions of interest on the water-only Dixon images outlining femur and acetabulum in both impingement (IJ) and healthy joints (HJ). 182 radiomic features were extracted for each hip. The dataset numerosity was increased by 60 times with an ad-hoc data augmentation tool. Features were subdivided by type and region in 24 subsets. For each, a univariate ANOVA F-value analysis was applied to find the 5 features most correlated with IJ based on p-value, for a total of 48 subsets. For each subset, a K-nearest neighbor model was trained to differentiate between IJ and HJ using the values of the radiomic features in the subset as input. The training was repeated 100 times, randomly subdividing the data with 75%/25% training/testing.

Results

The texture-based gray level features yielded the highest prediction max accuracy (0.972) with the smallest subset of features. This suggests that the gray image values are more homogeneously distributed in the HJ in comparison to IJ, which could be due to stress-related inflammation resulting from impingement.

Conclusions

We showed that radiomics can automatically distinguish IJ from HJ using water-only Dixon MRI. To our knowledge, this is the first application of radiomics for FAI diagnosis. We reported an accuracy greater than 97%, which is higher than the 90% accuracy for detecting FAI reported for standard diagnostic tests (90%). Our proposed radiomic analysis could be combined with methods for automated joint segmentation to rapidly identify patients with FAI, avoiding time-consuming radiological measurements of bone morphology.

Combined 3-Dimensional CT and Multidirectional CT Arthrography for Femoroacetabular Impingement and Hip Lesions: A Cross-sectional Study Comparing Imaging and Hip Arthroscopic Surgery Findings

Background

There is limited research investigating the diagnostic strength of 3-dimensional computed tomography (3D-CT) and multidirectional CT arthrography (CTA) for femoroacetabular impingement (FAI) and related hip lesions.

Purpose

To evaluate the diagnostic strength of combined 3D-CT and CTA in patients with FAI and related hip lesions by comparing it with hip arthroscopic surgery findings.

Study Design

Cohort study (diagnosis); Level of evidence, 2.

Methods

This study included patients who were suspected of having FAI and related hip lesions and who underwent a combination of 3D-CT and CTA and subsequent hip arthroscopic surgery between December 2013 and December 2017. The CT and intraoperative arthroscopic findings were recorded and compared. The sensitivity, specificity, and accuracy of 3D-CT for FAI and those of CTA for related hip lesions were calculated.

Results

A total of 114 patients with 114 hips were included in our study. There were 101 patients with positive findings and 13 patients with negative findings for FAI (including cam, pincer, and combined morphology) according to 3D-CT. The sensitivity, specificity, and accuracy of 3D-CT for FAI were 91.58%, 57.14%, and 89.47%, respectively. The sensitivity, specificity, and accuracy of CTA for labral tears were 94.64%, 100.00%, and 94.73%, respectively. For acetabular cartilage defects, the sensitivity, specificity, and accuracy of CTA were 60.71%, 91.37%, and 76.31%, respectively. For femoral cartilage defects, the sensitivity, specificity, and accuracy of CTA were 82.22%, 76.81%, and 78.94%, respectively.

Conclusion

The study results indicated that 3D-CT was able to provide excellent accuracy for FAI compared with hip arthroscopic surgery findings. In addition, multidirectional CTA demonstrated promising diagnostic strength for hip lesions such as labral tears and chondral defects.

Capsular closure versus unrepaired interportal capsulotomy after hip arthroscopy in patients with femoroacetabular impingement: results of a patient-blinded randomised controlled trial

BACKGROUND

Hip capsular management after hip arthroscopy remains a topic of debate. Most available current literature is of poor quality and are retrospective or cohort studies. As of today, no clear consensus exists on capsular management after hip arthroscopy.

PURPOSE

To evaluate the effect of routine capsular closure versus unrepaired capsulotomy after interportal capsulotomy measured with NRS pain and the Copenhagen Hip and Groin Outcome Score (HAGOS).

MATERIALS AND METHODS

All eligible patients with femoroacetabular impingement who opt for hip arthroscopy (n = 116) were randomly assigned to one of both treatment groups and were operated by a single surgeon. Postoperative pain was measured with the NRS score weekly the first 12 weeks after surgery. The HAGOS questionnaire was measured at 12 and 52 weeks postoperatively.

RESULTS

Baseline characteristics and operation details were comparable between treatment groups. Regarding the NRS pain no significant difference was found between groups at any point the first 12 weeks after surgery (p = 0.67). Both groups significantly improved after surgery (p < 0.001). After 3 months follow-up there were no differences between groups for the HAGOS questionnaire except for the domain sport (p = 0.02) in favour of the control group. After 12 months follow-up there were no differences between both treatment groups on all HAGOS domains (p > 0.05).

CONCLUSIONS

The results of this randomised controlled trial show highest possible evidence that there is no reason for routinely capsular closure after interportal capsulotomy at the end of hip arthroscopy.

TRIAL REGISTRATION

This trial was registered at the CCMO Dutch Trial Register: NL55669.048.15.

Adhesive Capsulitis of the Hip: A Case Presentation and Review

There remains a paucity of literature addressing adhesive capsulitis of the hip (ACH), making the diagnosis and treatment a continued challenge for healthcare providers. ACH encompasses restricted hip range-of-motion and pain that progresses through analogous Stages (1-4) to adhesive capsulitis of the shoulder. We report a case presentation of a middle-aged man that illustrates the significance of certain patient factors and provide a review of current literature to aid in the diagnostic evaluation and treatment for addressing ACH. Initial conservative treatment of ACH includes the appropriate management of associated comorbidities, oral and/or injectable pharmacologics, and physical therapy. While frequently resolving with time, refractory cases of ACH may require more aggressive approaches including pressure dilation, manipulation under anesthesia, synovectomy, capsular release and, for select patients, total hip arthroplasty. Given the limited available literature addressing ACH, healthcare providers may be forced to rely on a small number of published case reports and outdated review articles to guide their diagnostic evaluation and treatment approaches. Thus, this case presentation and review provides an updated approach to better diagnose and manage patients with ACH.

Association of Cam Deformity on Anteroposterior Pelvic Radiographs and More Severe Chondral Damage in Femoroacetabular Impingement Syndrome

BACKGROUND

Abnormal proximal femoral morphology in femoroacetabular impingement syndrome (FAIS) identifiable on the anteroposterior (AP) pelvic radiograph has been described as the "pistol grip" deformity. The effect of a superior cam deformity identified on this radiographic view remains unknown.

PURPOSES

To assess the relationship between AP cam deformity (AP alpha angle [AP AA] >55°) and cartilage injury; to assess the relationship between AP cam deformity and labral injury; and to determine if patient factors are correlated with cartilage and labral injury.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Patients undergoing osteochondroplasty and labral repair for FAIS with a single surgeon were identified retrospectively. Intraoperative size, location, and severity of cartilage and labral damage were prospectively collected. Chondrolabral and femoral/acetabular cartilage damage were graded with the Beck labral and cartilage injury criteria. Radiographic data included the AP AA, lateral center-edge angle (LCEA), and maximum femoral alpha angle (MF AA). Patients with hip dysplasia (LCEA <18°; LCEA 18°-25° with acetabular index >10°) were excluded. Outcomes were compared across cartilage and labral severity grades. We report odds ratios (ORs) with 95% confidence intervals and P values from multivariable logistic regressions.

RESULTS

Of the 158 included hips (154 patients), 69% were female and the mean (± standard deviation [SD]) age was 30.3 ± 9.7 years. Increase in age, increase in body mass index (BMI), and male sex were associated with increasing severity of cartilage and labral injury. More severe cartilage damage was associated with increasing AP AA (P < .001) and MF AA (P < .001). The odds of developing a higher category of cartilage injury severity (grade ≥3) were 119% higher (OR, 2.19 [95% CI, 1.36-3.64]; P = .002) for every SD increase (16.7°) in AP AA, adjusting for age, sex, and BMI. The odds of developing a severe labral injury (grade ≥3) were 118% higher (OR, 2.18 [95% CI 1.17-4.32]; P = .018) for every SD increase (10.5°) in MF AA, adjusting for age, sex, BMI, and AP AA.

CONCLUSION

Increasing age and BMI, and male sex are associated with increasing severity of cartilage and labral injury in FAIS. The odds of developing a cartilage injury are significantly higher with independent increases in AP AA and MF AA.

Full-length standing radiographs can be used for determination of the Femoral neck-shaft angle but not acetabular coverage

INTRODUCTION

The exact evaluation of hip morphology is essential for surgical planning. A wide range of morphometric measures of the acetabulum is deduced from conventional anterior-posterior (ap) pelvic radiographs. Full-length weight-bearing radiographs (FLWBR) also depict the acetabulum and are commonly used for osteotomy planning of the lower limb. This study aimed to determine whether FLWBR can be used to evaluate acetabular morphology.

METHODS

Radiographs of patients receiving a hip workup that included a conventional ap pelvic X-ray and FLWBR were utilized for radiographic measurements. The following parameters were measured: extrusion index of the femoral head, anterior wall index, posterior wall index, lateral center edge angle (LCE), acetabular index, pubic arc angle (subpubic angle), and centrum-collum-diaphyseal angle (CCD).

RESULTS

FLWBR depicted a significantly reduced anterior coverage (p = 0.049) and increased posterior coverage (p < 0.001), higher acetabular index (p = 0.015), and higher pubic-arc angle (p = 0.02) compared to conventional ap pelvic radiographs. There were no significant differences regarding the CCD angle (p = 0.28), extrusion index (p = 0.31), and LCE (p = 0.16).

DISCUSSION

The CCD angle of the femur can be measured on conventional ap radiographs and full-length weight-bearing X-rays for lower limb deformity analysis. However, FLWBR will depict an anteverted acetabular morphology, rendering conventional ap radiographs necessary for planning pelvic osteotomies.

High bone mass and cam morphology are independently related to hip osteoarthritis: findings from the High Bone Mass cohort

BACKGROUND

High bone mass (HBM, BMD Z-score ≥  + 3.2) and cam morphology (bulging of lateral femoral head) are associated with greater odds of prevalent radiographic hip osteoarthritis (rHOA). As cam morphology is itself a manifestation of increased bone deposition around the femoral head, it is conceivable that cam morphology may mediate the relationship between HBM and rHOA. We therefore aimed to determine if individuals with HBM have increased odds of prevalent cam morphology. In addition, we investigated whether the relationship between cam and prevalent and incident osteoarthritis was preserved in a HBM population.

METHODS

In the HBM study, a UK based cohort of adults with unexplained HBM and their relatives and spouses (controls), we determined the presence of cam morphology using semi-automatic methods of alpha angle derivation from pelvic radiographs. Associations between HBM status and presence of cam morphology, and between cam morphology and presence of rHOA (or its subphenotypes: osteophytes, joint space narrowing, cysts, and subchondral sclerosis) were determined using multivariable logistic regression, adjusting for age, sex, height, weight, and adolescent physical activity levels. The association between cam at baseline and incidence of rHOA after an average of 8 years was determined. Generalised estimating equations accounted for individual-level clustering.

RESULTS

The study included 352 individuals, of whom 235 (66.7%) were female and 234 (66.5%) had HBM. Included individuals contributed 694 hips, of which 143 had a cam deformity (20.6%). There was no evidence of an association between HBM and cam morphology (OR = 0.97 [95% CI: 0.63-1.51], p = 0.90) but a strong relationship was observed between cam morphology and rHOA (OR = 3.96 [2.63-5.98], p = 5.46 × 10-11) and rHOA subphenotypes joint space narrowing (OR = 3.70 [2.48-5.54], p = 1.76 × 10-10), subchondral sclerosis (OR = 3.28 [1.60-6.60], p = 9.57 × 10-4) and osteophytes (OR = 3.01 [1.87-4.87], p = 6.37 × 10-6). Cam morphology was not associated with incident osteoarthritis (OR = 0.76 [0.16-3.49], p = 0.72).

CONCLUSIONS

The relationship between cam morphology and rHOA seen in other studies is preserved in a HBM population. This study suggests that the risk of OA conferred by high BMD and by cam morphology are mediated via distinct pathways.

Anthropometric measurements of the pediatric hip using CT-based simulated anteroposterior radiographs of the pelvis

Normal anatomical variants and pathological deformities of the pediatric hip can only be differentiated after a prior definition of normal ranges for anthropometric parameters with increasing age. Aim of the present study was to provide reliable reference values of the pediatric hip morphometry, using computed tomography (CT)-based rotation-corrected summation images of the pelvis that simulate the widely available plain radiograph-based measurements, but offer the higher precision of the CT technique. This retrospective study included 85 patients (170 hips) under 15 years of age (0-15). The measured anthropometric parameters included femur head extrusion index, lateral center-edge angle, acetabular inclination, Tönnis angle, and femoral neck-shaft angle. Mean values, range, SD, P values, intra-rater, and inter-rater reliability were calculated. All measurements correlated with age. None of the measurements correlated with gender or side. Rapid growth phases were noted in all measurements at the age of 12 (14 in males and 11 in females). The inter-rater and intra-rater reliability was high (range inter/intraclass correlation coefficient 0.926-0.998 Cronbach's alpha 0.986-0.998). The present work provides age- and gender-related normative values of the classically used hip measurements as well as growth phases describing pediatric hip morphology in a broad age range. A discrepancy was noted between the values measured in the current study and the classical X-ray-based reference values in the literature especially for the Tönnis angle and LCEA values. This suggests that the rotation and inclination correction in the CT-based techniques might have the advantage of compensating for a possible overestimation in the conventional X-ray-based methods.

[Femoroacetabular impingement syndrome in adolescents-How to adivse? How to treat?]

Hintergrund

Das Femoroazetabuläre Impingement-Syndrom (FAIS) ist eine relevante Ursache für Leistenschmerzen beim Jugendlichen. Insbesondere sind Sportler betroffen.

Ziel der Arbeit

Die Arbeit soll einen evidenzbasierten Hintergrund für Beratung und Therapie des FAIS beim Adoleszenten bieten.

Material und Methoden

Anhand der aktuellen Literatur wurde eine Übersicht zu Prävalenz und Pathogenese, Abklärung und Diagnostik sowie therapeutischen Empfehlung des FAIS beim Adoleszenten erarbeitet.

Ergebnisse und Diskussion

Das FAIS beim Jugendlichen betrifft vor allem sportlich aktive Patienten. Bestimmte Sportarten begünstigen die Entstehung eines FAIS. Cam-Impingement, Pincer-Impingement und kombiniertes FAIS sind die häufigsten Entitäten in dieser Altersgruppe. Die Cam-Morphologie entsteht kurz vor Schluss der proximalen Femurwachstumsfuge. Beim Cam-Impingement muss die Epiphyseolysis capitis femoris (ECF) von der primären Cam-Morphologie unterschieden werden. Die ECF verlangt eine rasche operative Versorgung mit Stabilisierung der Epiphyse, während das primäre Cam-Impingement elektiv abgeklärt werden kann und ein konservativer Behandlungsversuch sinnvoll ist. Schäden an Labrum und Knorpel werden regelhaft beobachtet. Eine systematische radiologische Abklärung mittels Projektionsröntgen und MRT ist obligat, um einen adäquaten Therapieplan zu entwickeln. Bei jugendlichen Patienten mit FAIS sollte immer ein konservativer Therapieversuch erfolgen. Ist dieser nicht erfolgreich, ist die operative Sanierung mit Hüftarthroskopie indiziert. Die postoperativen Ergebnisse zeigen bei Jugendlichen sehr gute Erfolge mit rascher Besserung der Beschwerden, geringen Komplikationen und einer hohen „Return-to-sport“-Rate.

How to Report: Hip MRI

Writing a good magnetic resonance imaging (MRI) hip report requires a sound understanding of hip anatomy, imaging, and related pathologies. The structures of the hip most prone to pathology are the articular surfaces, labrum, subchondral bone, and gluteal tendons. Particular attention should be paid to abnormal hip morphology that is relatively common and can manifest as internal or external hip derangement. It is essential to appreciate and report the specific features of each pathology that carry clinical significance to aid patient management. This article is aimed at trainee radiologists and those less experienced with reporting hip MRI, focusing on the essential features to comment on and providing examples of terminology to use and MR images to illustrate these features.

Preoperative Dynamic Hip Examination Under Fluoroscopic Guidance Enhances the Understanding of Femoroacetabular Impingement Pathology and Treatment Planning

Purpose

To review the relative accuracy of preoperative magnetic resonance imaging (MRI) and fluoroscopically guided examination-under-sedation (EUS) findings and to explore the validity of the anterior acetabular sector angle (AASA) as a radiologic MRI-based marker of anterior acetabular coverage in pincer-type impingement.

Methods

A cohort of 150 consecutive patients undergoing primary hip arthroscopy for femoroacetabular impingement (FAI) in 2018 to 2019 was reviewed. The inclusion criteria were pure FAI unilateral symptomatic pathology and the availability of complete data sets (MRI, EUS, and intraoperative records). Preoperative MRI and EUS findings were compared with gold-standard intraoperative arthroscopic findings, specifically evaluating the alpha angle in the presence of cam lesions, AASA in the presence of pincer lesions, as well as soft-tissue lesions. An alpha angle greater than 50° and an AASA greater than 65° were deemed pathologic.

Results

The patient cohort included 78 women and 72 men with an average age of 38 years (range, 18-53 years). Intraoperatively, pincer lesions were present in 20% of patients; cam lesions, 26%; and mixed impingement, 54%. MRI versus EUS correctly identified pincer lesions in 36% versus 89% of cases and identified cam lesions in 44% versus 77% of cases. MRI findings characterizing labral tears and articular cartilage pathology were accurate in 80% and 10% of cases, respectively. Although there was no difference in the AASA between pure pincer- and mixed-type impingements (62° and 63°, respectively; P = .62), there was a statistically significant difference in reported AASA values between pure cam-type impingement and impingement involving the presence of pincer lesions (57° and 63°, respectively; P = .03). Furthermore, 31% of patients with intraoperatively identified pincer lesions had an AASA of 60° to 65°.

Conclusions

Fluoroscopic EUS is accurate in characterizing FAI pathology. In addition, MRI is useful to diagnose or rule out non-FAI pathology, ascertain labral pathology, and outline hip alignment. These methods of preoperative planning are complementary.

Level of Evidence

Level IV, therapeutic case series.

Cam morphology but neither acetabular dysplasia nor pincer morphology is associated with osteophytosis throughout the hip: findings from a cross-sectional study in UK Biobank

OBJECTIVES

To examine whether acetabular dysplasia (AD), cam and/or pincer morphology are associated with radiographic hip osteoarthritis (rHOA) and hip pain in UK Biobank (UKB) and, if so, what distribution of osteophytes is observed.

DESIGN

Participants from UKB with a left hip dual-energy X-ray absorptiometry (DXA) scan had alpha angle (AA), lateral centre-edge angle (LCEA) and joint space narrowing (JSN) derived automatically. Cam and pincer morphology, and AD were defined using AA and LCEA. Osteophytes were measured manually and rHOA grades were calculated from JSN and osteophyte measures. Logistic regression was used to examine the relationships between these hip morphologies and rHOA, osteophytes, JSN, and hip pain.

RESULTS

6,807 individuals were selected (mean age: 62.7; 3382/3425 males/females). Cam morphology was more prevalent in males than females (15.4% and 1.8% respectively). In males, cam morphology was associated with rHOA [OR 3.20 (95% CI 2.41-4.25)], JSN [1.53 (1.24-1.88)], and acetabular [1.87 (1.48-2.36)], superior [1.94 (1.45-2.57)] and inferior [4.75 (3.44-6.57)] femoral osteophytes, and hip pain [1.48 (1.05-2.09)]. Broadly similar associations were seen in females, but with weaker statistical evidence. Neither pincer morphology nor AD showed any associations with rHOA or hip pain.

CONCLUSIONS

Cam morphology was predominantly seen in males in whom it was associated with rHOA and hip pain. In males and females, cam morphology was associated with inferior femoral head osteophytes more strongly than those at the superior femoral head and acetabulum. Further studies are justified to characterise the biomechanical disturbances associated with cam morphology, underlying the observed osteophyte distribution.

Arthroscopic Management of Femoroacetabular Impingement in Adolescents: A Systematic Review

BACKGROUND

Femoroacetabular impingement (FAI) is highly prevalent in adolescent athletes. There has been an increasing trend for arthroscopic surgery for FAI, and the results of several clinical studies on outcome after arthroscopic surgery for FAI are available.

PURPOSE

To conduct a systematic review to investigate the role of arthroscopic management for FAI in adolescents.

STUDY DESIGN

Systematic review.

METHODS

This systematic review was conducted according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. In August 2020, PubMed, Scopus, Google Scholar, and EMBASE were accessed. All clinical trials concerning the arthroscopic treatment for adolescents with FAI were identified. Only studies on patients aged less than 18 years at the time of surgery reporting data over a minimum follow-up of 12 months were considered.

RESULTS

Data from 406 adolescents (470 procedures; mean age at surgery, 15.9 years; mean follow-up, 30.4 months) with FAI were retrieved. At a mean of 28.0 months of follow-up, 94% of the adolescents had already returned to sport. All the scores of interest were improved at the final follow-up: visual analog scale (P = .01), modified Harris Hip Score (P < .0001), Non-Arthritic Hip Score (P = .03), Hip Outcome Score-Activities of Daily Living (P = .01), Hip Outcome Score-Sport-Specific Subscale (P < .0001), and Tegner score (P < .0001). Complications occurred in 1.1% (5/470) of procedures, and revision arthroscopy was performed in 4.7% (22/470) of procedures.

CONCLUSION

Arthroscopic surgery in adolescents with FAI achieves excellent outcomes and a high rate of return to sport, with rates of complication and revision surgery of 1% and 5%, respectively.

Femoral cartilage damage occurs at the zone of femoral head necrosis and can be accurately detected on traction MR arthrography of the hip in patients undergoing joint preserving hip surgery

The primary purpose was to answer the following question: What is the location and pattern of necrosis and associated chondrolabral lesions and can they be accurately detected on traction MR arthrography compared with intra-operative findings in patients undergoing hip preservation surgery for femoral head necrosis (FHN)? Retrospective, diagnostic case series on 23 patients (23 hips; mean age 29 ± 6 years) with diagnosis of FHN undergoing open/arthroscopic joint preserving surgery for FHN and pre-operative traction MR arthrography of the hip. A MR-compatible device for weight-adapted application of leg traction (15-23 kg) was used and coronal, sagittal and radial images were acquired. Location and pattern of necrosis and chondrolabral lesions was assessed by two readers and compared with intra-operative findings to calculate diagnostic accuracy of traction MR arthrography. On MRI all 23 (100%) hips showed central FHN, most frequently antero-superiorly (22/23, 96%) where a high prevalence of femoral cartilage damage was detected (18/23, 78%), with delamination being the most common (16/23, 70%) damage pattern. Intra-operative inspection showed central femoral head cartilage damage most frequently located antero-superiorly (18/23, 78%) with femoral cartilage delamination being most common (14/23, 61%). Traction MR arthrography enabled detection of femoral cartilage damage with a sensitivity/specificity of 95%/75% for reader 1 and 89%/75% for reader 2. To conclude, femoral cartilage damage occurs at the zone of necrosis and can be accurately detected using traction MR arthrography of the hip which may be helpful for surgical decision making in young patients with FHN.

The Role of Imaging in Femoroacetabular Impingement: History, Current Practices, and Future Applications

»

Femoroacetabular impingement (FAI) is one of the most common causes of early hip articular cartilage wear and labral damage, and subsequently leads to the onset of hip osteoarthritis.

»

Cam-type FAI impingement lesions can be best identified with a 90° Dunn lateral radiograph and a cross-table lateral radiograph with 15° of internal rotation; the alpha angle and the femoral head-neck offset are the most used predictive radiographic markers.

»

FAI lesions with pincer impingement are associated with acetabular retroversion and are more difficult to identify on traditional radiographic imaging; however, the presence of a crossover sign, an ischial spine sign, and/or a posterior wall sign can be useful radiographic markers.

»

Advanced imaging modalities such as magnetic resonance imaging (MRI) and/or magnetic resonance arthrography (MRA) can also be beneficial in the evaluation of FAI and labral pathology; MRA is more sensitive than MRI in detecting intra-articular pathology.

»

Computer-assisted navigation for preoperative planning and intraoperative surgical assistance are promising technologies; however, additional studies are needed before they can be utilized safely and effectively.

The Utility of MRI to Diagnose Ischifemoral Impingement by Assessing the Ischiofemoral and Quadratus Femoris Spaces During Femoral External Rotation

OBJECTIVE

The purpose of this study was to explore if the dimensions of the ischiofemoral space on MRI vary with changes in external femoral rotation in Ischifemoral Impingement patients relative to healthy control; if so, to determine the optimal diagnostic cutoff values of these dimensions in Ischifemoral Impingement.

METHODS

The study included 43 clinically confirmed Ischifemoral Impingement patients and 50 healthy volunteers. All subjects underwent hip MRI examinations with their hips externally rotated at 0°, 30°, and 60°. The IFS and QFS were measured respectively at each angle. The measurements were compared between the IFI group and the control group to determine the optimal diagnostic cutoff values for diagnosing IFI by using IFS and QFS measurements.

RESULTS

In the IFI group, the spaces were smaller than those of the control group at all rotation angles (P < 0.05 for each). When external rotation angles were increased, the IFS and QFS tended to decrease. QFSs were smaller in the case group than the control group at each rotation angle. The receiver operating characteristic areas under the curves of IFS and QFS in a neutral position of 0° were highest.

CONCLUSION

Both of the IFS and QFS spaces of IFI patients were found to be smaller than those of the control group, regardless of the external hip rotation angles. A neutral position of 0° was deemed the best position for diagnosing IFI. The diagnostic cutoff values of IFS and QFS were 2.44cm and 1.34cm in the neutral position, respectively.

Femoroacetabular Impingement of the Hip Joint – Literature Review

Introduction: In patients with painful hip joint, femoroacetabular impingement is a relatively frequently diagnosed condition. Study aim: The aim of the study was to present the anatomy, biomechanics and pathomechanism of femoroacetabular impingement, surgical diagnostics and treatment, as well as physiotherapeutic procedures, and to provide answers to the following questions: 1. What are the causes of femoroacetabular impingement development and what is its most common form? 2. What are the clinical and imaging diagnosis of femoroacetabular impingement based on? 3. What are the goals of physiotherapeutic treatment in the treatment of patients with postoperative femoroacetabular impingement? Material and method: Current professional literature was analysed based on a review of Internet databases, including Pubmed and Google Scholar. Results: From the abovementioned Internet databases, 30 items from the current profession-al literature on the analysed variables were identified. Conclusions: The reasons for the development of femoroacetabular impingement are com-plex, including developmental disorders of the hip joint or its chronic overload. Its most common form is mixed type. The basic imaging test used is anterior-posterior X-ray, while clinical assessment is based on anterior-posterior impingement test. Physiotherapy should be individually tailored and focused on improving range of motion and muscle strength of the hip joint.

The Use of Biologics for Hip Preservation

PURPOSE OF REVIEW

A wide array of nonoperative modalities to treat hip pain are aimed at restoring and maintaining the structural and physiologic characteristics of the joint. The purpose of this review is to describe the current understanding of biologics in hip pathology by providing an evidence-based overview of treatment modalities available for orthopedic surgeons.

RECENT FINDINGS

The use of biologics as a primary treatment or adjunct to traditional management has shown encouraging results for the treatment of hip pain. Studies have demonstrated safety with minimal complications when using platelet rich plasma, hyaluronic acid, or stem cells to treat hip pain caused by osteoarthritis, femoroacetabular impingement syndrome, tendinopathy, or osteonecrosis of the femoral head. Several studies have been able to demonstrate meaningful clinical results that can improve treatment standards for hip pain; however, more work must be performed to better delineate the appropriate protocols, indications, and limitations of each modality. Recent advances have inspired renewed interest in biologics for patients with hip pain. We present a concise review of platelet rich plasma, hyaluronic acid, stem cells, and matrix metalloprotease inhibitors and their applicability to hip preservation surgery.

The influence of pain catastrophizing and central sensitization on the reported pain after hip arthroscopy

PURPOSE

This study was conducted to investigate whether the pain catastrophizing scale (PCS) and the central sensitization inventory (CSI) are predictive factors for the reported pain after hip arthroscopy.

METHODS

A total of 37 patients undergoing hip arthroscopy for femoroacetabular impingement syndrome and labral tears were prospectively enrolled. All patients completed the PCS and CSI before hip arthroscopy. Postoperative pain was measured with the numeric rating scale (NRS) weekly the first 12 weeks after surgery by electronic diary.

RESULTS

At baseline, univariate analyses showed that both the CSI and PCS were significantly associated with the NRS outcome (p < 0.01). During 12 weeks follow-up, a significant decrease on the NRS was observed (p < 0.01). Univariate analyses showed that both the CSI and PCS were significantly associated with the NRS during follow-up. Multivariate mixed model analysis showed that only the PCS remained significantly associated with the NRS outcome with a ß of 0.07 (95% CI 0.03-0.11, p < 0.01).

CONCLUSION

Results indicate that both the PCS and CSI are associated with the reported postoperative pain after hip arthroscopy. The PCS and CSI may be useful in daily practice to identify patients that possibly benefit from pain catastrophizing reduction therapy (e.g. counseling) prior to surgery.

LEVEL OF EVIDENCE

IV.

Magnetic resonance imaging of the hip: anatomy and pathology

The aim of this review is to outline the normal anatomy of the hip and to discuss common painful conditions of the hip that affect the general adult population. Hip pain is a common complaint with many different etiologies. In this review, hip pathologies are divided by location into osseous, intra-articular and extra-articular lesions. Magnetic resonance imaging (MRI) is the modality of choice for investigating painful hip conditions due to its multiplanar capability and high contrast resolution. This review focuses on the characteristic MRI features of common traumatic and pathologic conditions of the hip.

The Lisbon Agreement on Femoroacetabular Impingement Imaging-part 1: overview

OBJECTIVES

Imaging assessment for the clinical management of femoroacetabular impingement (FAI) syndrome remains controversial because of a paucity of evidence-based guidance and notable variability in clinical practice, ultimately requiring expert consensus. The purpose of this agreement is to establish expert-based statements on FAI imaging, using formal techniques of consensus building.

METHODS

A validated Delphi method and peer-reviewed literature were used to formally derive consensus among 30 panel members (21 musculoskeletal radiologists and 9 orthopaedic surgeons) from 13 countries. Forty-four questions were agreed on, and recent relevant seminal literature was circulated and classified in five major topics ('General issues', 'Parameters and reporting', 'Radiographic assessment', 'MRI' and 'Ultrasound') in order to produce answering statements. The level of evidence was noted for all statements, and panel members were asked to score their level of agreement with each statement (0 to 10) during iterative rounds. Either 'consensus', 'agreement' or 'no agreement' was achieved.

RESULTS

Forty-seven statements were generated, and group consensus was reached for 45 (95.7%). Seventeen of these statements were selected as most important for dissemination in advance. There was no agreement for the two statements pertaining to 'Ultrasound'.

CONCLUSION

Radiographic evaluation is the cornerstone of hip evaluation. An anteroposterior pelvis radiograph and a Dunn 45° view are recommended for the initial assessment of FAI although MRI with a dedicated protocol is the gold standard imaging technique in this setting. The resulting consensus can serve as a tool to reduce variability in clinical practices and guide further research for the clinical management of FAI.

KEY POINTS

• FAI imaging literature is extensive although often of low level of evidence. • Radiographic evaluation with a reproducible technique is the cornerstone of hip imaging assessment. • MRI with a dedicated protocol is the gold standard imaging technique for FAI assessment.

Does MR arthrography cause intracranial gadolinium deposition?

PURPOSE

To determine (i) whether intra-articular gadolinium from MR arthrography (MRA) results in gadolinium deposition in the brain and (ii) whether there is a correlation between intra-articular gadolinium dose and intracranial gadolinium deposition.

MATERIALS AND METHODS

This retrospective study was institutional review board (IRB) approved and HIPAA compliant. The study group included consecutive adult patients who had undergone MRA of the hip or shoulder and subsequent MRI of the brain. None of the patients had a history of intravenous gadolinium exposure. A control group of patients of similar age and sex who were never exposed to gadolinium and had brain MRIs available was included. Signal intensities (SI) of four brain regions: pons, dentate nuclei (DN), globus pallidi (GP), and thalamus (Thal) normalized to cerebrospinal fluid (CSF) and expressed in SI ratios were measured on T1-weighted non-contrast MR images. Groups were compared using the student's t test. Linear correlation analysis of gadolinium dose and brain SI ratios was performed, and Pearson correlation coefficients (r) are reported.

RESULTS

We identified 109 patients (mean age 44 ± 14 years, 54% men) who had undergone MRA and 149 controls of similar age and sex distribution. There was no significant difference in mean SI ratios of the brain regions between patients and controls: pons/CSF (p = 0.7), DN/CSF (p = 0.4), GP/CSF (p > 0.99), Thal/CSF (p = 0.3). Within the MRA group, gadolinium dose was not associated with SI ratios (p > 0.2).

CONCLUSION

Our study found no MR evidence of intracranial gadolinium deposition following MRA. In addition, there was no association between intra-articular gadolinium dose and SI ratios in commonly affected regions of the brain.

Return to Sport After Femoroacetabular Impingement Surgery and Sport-Specific Considerations: a Comprehensive Review

PURPOSE OF REVIEW

Recent advancements in surgical technology and techniques have improved functional results for operative treatment of femoroacetabular impingement syndrome (FAIS). Few studies have comprehensively evaluated the literature regarding return to sport criteria, timing, level, and rates. The purpose of this study was to review recent studies regarding return to play after surgical correction of FAIS. We will specifically evaluate the level of return to play and look to compare pre- and postoperative competition levels when available. We will also analyze timing of return to play from injury to surgery. Additionally, we will elucidate any sport-specific criteria that may determine readiness for return.

RECENT FINDINGS

Athletes with FAIS treated non-operatively have a low rate of return to sport and are often functionally limited in their level of performance. Surgical management of FAIS includes hip arthroscopy as well as open techniques. Current literature suggests a high rate of return to sport after contemporary surgery for FAIS at 87-93% overall. Rate of return to the same level of competition following surgery for FAIS is 55-83% in pooled studies. Limited evidence is available comparing postoperative rehabilitation protocols and timing of return among different sports. Operative treatment of FAIS results in high rates of return to sport and functional performance. The results of this study may help educate patients preoperatively in regard to the likelihood of functional return to sport and sport-specific considerations. Further research evaluating rehabilitation protocols and return criteria may better elucidate timing intervals for patients to maximize function while limiting complications.

Surgical hip dislocation is more powerful than arthroscopy for achieving high degrees of acetabular correction in pincer type impingement

BACKGROUND

With the development of hip arthroscopy (HA), a shift away from surgical hip dislocation (SHD) is becoming a noticeable reality. It was the aim of this study to examine whether SHD provides a benefit over HA regarding its corrective power in the treatment of femoroacetabular impingement (FAI).

HYPOTHESIS

It was hypothesized that SHD provides the more powerful tool for acetabular correction in FAI surgery compared to HA.

METHOD

The examined cohort consisted of 85 hips of which 31 (36%) underwent a high degree of acetabular correction which was defined as a correction of >2 standard deviations from the population mean. A lateral center edge angle (LCE) correction>12° or an acetabular index (AI) correction>8° were therefore considered to high correction. A logistic regression model was applied to determine factors influencing high correction in FAI surgery. Subsequent adjustment was performed using a multivariate model.

RESULTS

After adjusting for pre-operative acetabular orientation, SHD showed a pronounced influence on the likelihood of achieving the adequate degree of high acetabular correction (odds ratio (OR) 10.0 confidence interval (C.I) 2.3 to 44.0, p=0.002). On the other hand, SHD showed no influence on femoral correction (p=n.s).

CONCLUSION

Surgical hip dislocation is a powerful modality for achieving high degrees of acetabular correction in the situation of a femoroactabular conflict, being defined as an LCE correction of>12° or AI correction of>8°. The reason for these results may be seen in the excellent exposure and the improved possibility of performing dynamic intra-operative examination to verify the results. The benefits are only limited to large acetabular correction. These findings should provide a helpful tool for decision making in clinical practise.

LEVEL OF EVIDENCE

Level III retrospective cohort study.

Management of femoroacetabular impingement syndrome: current insights

Since the description of femoroacetabular impingement (FAI) by Ganz in 2003, our understanding of the pathophysiology, management options, and outcomes has evolved and literature continues to be generated on this condition at a rapid rate. FAI has been identified as a primary source of hip pain as well as a generator of secondary osteoarthritis. Improvements in the radiographic detection of cam and pincer morphologies as well as a better understanding of the structural impact of these morphologies have led to improved preoperative planning. Advancements in hip arthroscopy techniques have also led to a higher rate of arthroscopic management of this condition over the initially described open surgical dislocation technique. While arthroscopic management of this condition has become the most common form of surgical management for FAI, inadequate bony resection has been shown to be a frequent source of revision surgery. Therefore, roles for open surgical dislocation and combined mini-open approaches remain, particularly in cases where concern for the inability to fully access the morphology arthroscopically exists.

Editorial Commentary: Low-Dose Hip Computed Tomography Sharpens the Saw for Hip Preservation: Can It Cut the Tree?

Computed tomography scans provide excellent visualization of complex hip deformities and assist in the diagnosis and surgical planning of hip preservation surgery. The dose of harmful ionizing radiation can be reduced while preserving reasonable image quality. Low-dose hip computed tomography can be used successfully for preoperative planning. Readers should consider strategies to reduce the radiation dose from computed tomography scans and consider magnetic resonance imaging arthrograms for assessment of cartilage and labral status before hip preservation surgery.