3.0T conventional hip MR and hip MR arthrography for the acetabular labral tears confirmed by arthroscopy

Comparison of 3T MR arthrography and 3T MRI in intra-articular hip pathology: a cost-analysis

BACKGROUND

MR arthrography (MRA) has previously been the radiological gold standard for investigating labral and chondral lesions of the hip joint. In recent years, 3T MRI has demonstrated comparable accuracy, being adopted as the first-line imaging investigation in many institutions.

AIMS

We compare the associated increased cost and radiation dose of the fluoroscopic component of the MRA compared to MRI.

METHODS

In this retrospective review over 2 years, 120 patients (mean age 27.3 years ± 13.2, range 8-67) underwent 3T MRA or non-contrast 3T MRI. Three musculoskeletal radiologists reported the data independently. Primary objectives included cost-comparison between each and radiation dose of the fluoroscopic component of the MRA. Secondary objectives included comparing detection of pathology involving the acetabular labrum, femoral cartilage, and acetabular cartilage.

RESULTS

Then, 58 (48%) underwent 3T MRA and 62 (52%) patients underwent 3T MRI. The added cost of the fluoroscopic injection prior to MRA was €116.31/patient, equating to €7211.22 savings/year. MRA was associated with a small radiation dose of 0.003 mSv.

CONCLUSIONS

Transitioning from 3T MRA to 3T MRI in the investigation of intra-articular hip pathology increases cost savings and reduces radiation dose.

A New Arthroscopic Classification for Chondrolabral Disease in Patients Undergoing Surgery for Developmental Dysplasia of the Hip

BACKGROUND

Current classification systems for intra-articular pathology intraoperatively have been described for patients with femoroacetabular impingement rather than dysplasia.

PURPOSE

To (1) describe intra-articular findings in dysplastic hips undergoing combined hip arthroscopy and periacetabular osteotomy (PAO); (2) propose a new chondrolabral classification system for dysplastic hips based on these findings; and (3) correlate patient-reported outcome measures (PROM) with the newly proposed classification.

STUDY DESIGN

Case series; Level of evidence, 4.

METHODS

A total of 46 hips underwent combined hip arthroscopy and PAO at our institution between September 2013 and December 2014, irrespective of symptoms or radiographic findings. PROMs were evaluated preoperatively and at 2 years postoperatively. At the time of hip arthroscopy, the chondrolabral junction was classified as normal without tear (1 hip, type 1); hypertrophic labrum without chondrolabral disruption (19 hips, type 2); chondrolabral disruption on the articular side, not extending into the capsular side (16 hips, type 3A); chondrolabral disruption extending through the capsular side (3 hips, type 3B); and exposed acetabular subchondral bone (7 hips, type 4).

RESULTS

There was a significant difference in postoperative modified Harris Hip Score (mHHS) (P = .020), Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain scores (P = .037), and WOMAC total scores (P = .049) between chondrolabral junction types. Post hoc analyses demonstrated significant differences between type 2 (84.9 ± 12.9) and type 3A (67.8 ± 20.7; P = .198), and between type 2 and type 4 (59.3 ± 24.3; P = .011) in postoperative mHHS scores; and between type 2 (83.9 ± 12.9) and type 3A (68.9 ± 23.7; P = .045) in postoperative WOMAC total scores. In multivariate analysis, chondrolabral type 3 or type 4, age >35 years, and previous surgery were significantly correlated with worse mHHS scores at 2 years.

CONCLUSION

This new chondrolabral classification is proposed to describe intra-articular pathology seen during combined hip arthroscopy and PAO, specifically in dysplastic hips. More advanced chondrolabral disease was associated with worse PROMs at 2 years.

SSR white paper: guidelines for utilization and performance of direct MR arthrography

OBJECTIVE

Direct magnetic resonance arthrography (dMRA) is often considered the most accurate imaging modality for the evaluation of intra-articular structures, but utilization and performance vary widely without consensus. The purpose of this white paper is to develop consensus recommendations on behalf of the Society of Skeletal Radiology (SSR) based on published literature and expert opinion.

MATERIALS AND METHODS

The Standards and Guidelines Committee of the SSR identified guidelines for utilization and performance of dMRA as an important topic for study and invited all SSR members with expertise and interest to volunteer for the white paper panel. This panel was tasked with determining an outline, reviewing the relevant literature, preparing a written document summarizing the issues and controversies, and providing recommendations.

RESULTS

Twelve SSR members with expertise in dMRA formed the ad hoc white paper authorship committee. The published literature on dMRA was reviewed and summarized, focusing on clinical indications, technical considerations, safety, imaging protocols, complications, controversies, and gaps in knowledge. Recommendations for the utilization and performance of dMRA in the shoulder, elbow, wrist, hip, knee, and ankle/foot regions were developed in group consensus.

CONCLUSION

Although direct MR arthrography has been previously used for a wide variety of clinical indications, the authorship panel recommends more selective application of this minimally invasive procedure. At present, direct MR arthrography remains an important procedure in the armamentarium of the musculoskeletal radiologist and is especially valuable when conventional MRI is indeterminant or results are discrepant with clinical evaluation.

Can the Acetabular Labrum Be Reconstructed With a Meniscal Allograft? An In Vivo Pig Model

BACKGROUND

No single graft type has been shown to have a benefit in acetabular labral reconstruction. The native labrum and lateral meniscus share many similarities, suggesting that the meniscus may be a promising source of graft material in labral reconstruction.

QUESTIONS/PURPOSES

Using a pig model, we sought to evaluate the healing process of fresh-frozen meniscus allograft for acetabular reconstruction by assessing (1) MRI and macroscopic observations of the meniscus allograft; (2) histologic appearance and immunohistologic evaluation of the meniscus allograft, native meniscus, and labrum; (3) microscopic assessment of the native labrum and meniscus via scanning electron microscopy; and (4) biomechanical assessment of tensile properties.

METHODS

Twelve skeletally mature male miniature Bama pigs (24 hips) were randomly divided into two groups: labral defect group (control) and lateral meniscus allograft group. The selection of Bama pig specimens was based on the similarity of their acetabular labrum to that of the human acetabular labrum, characterized by the presence of fibrocartilage-like tissue lacking blood vessels. The pigs underwent bilateral hip surgery. Briefly, a 1.5-cm-long section was resected in the anterior dorsal labrum, which was left untreated or reconstructed using an allogeneic lateral meniscus. The pigs were euthanized at 12 and 24 weeks postoperatively, and then evaluated by macroscopic observations and MRI measurement to assess the extent of coverage of the labral defect. We also performed a histologic analysis and immunohistologic evaluation to assess the composition and structure of meniscus allograft, native labrum, and meniscus, as well as scanning electron microscopy assessment of the microstructure of the native labrum and meniscus and biomechanical assessment of tensile properties.

RESULTS

Imaging measurement and macroscopic observations revealed that the resected area of the labrum was fully filled in the lateral meniscus allograft group, whereas in the control group, the labral defect remained at 24 weeks. The macroscopic scores of the meniscus allograft group (8.2 ± 0.8) were higher than those of the control groups (4.8 ± 1.0) (mean difference 3.3 [95% CI 1.6 to 5.0]; p < 0.001). Moreover, in the meniscus allograft group, histologic assessment identified fibrocartilage-like cell cluster formation at the interface between the graft and acetabulum; cells and fibers arranged perpendicularly to the acetabulum and tideline structure that were similar to those of native labrum could be observed at 24 weeks. Immunohistochemical results showed that the average optical density value of Type II collagen at the graft-acetabulum interface was increased in the meniscus allograft group at 24 weeks compared with at 12 weeks (0.259 ± 0.031 versus 0.228 ± 0.023, mean difference 0.032 [95% CI 0.003 to 0.061]; p = 0.013). Furthermore, the tensile modulus of the lateral meniscus allograft was near that of the native labrum at 24 weeks (54.7 ± 9.9 MPa versus 63.2 ± 11.3 MPa, mean difference -8.4 MPa [95% CI -38.3 to 21.4]; p = 0.212).

CONCLUSION

In a pig model, lateral meniscus allografts fully filled labral defects in labral reconstruction. Regeneration of a fibrocartilage transition zone at the graft-acetabulum interface was observed at 24 weeks.

CLINICAL RELEVANCE

The use of an autograft meniscus for labral reconstruction may be a viable option when labral tears are deemed irreparable. Before its clinical implementation, it is imperative to conduct a comparative study involving tendon grafts, which are extensively used in current clinical practice.

The correlation between hip alpha angle and acetabular labral tear location and size: A cross-sectional study

BACKGROUND

Explore the correlation between hip morphology and labral tear location/size.

METHODS

This retrospective study analyzed patients with hip pain who received magnetic resonance (MR) arthrography at our institution, between January 2017 and December 2020. Imaging analysis includes labral tear location and size, and hip morphology measurement with alpha angle, lateral center-edge (CE) angle, anterior CE angle, and femoral neck version. The correlation between hip morphology angles and labral tear location/size was evaluated using multiple regression, followed by stratification analysis with Chi-square test to investigate interactions between the variables.

RESULTS

A total of 103 patients (105 hips) with hip pain who received MR arthrography (mean age, 50 years ± 15 [SD]) were included, with mean alpha angle of 57.7° ± 9.9° [SD], mean lateral CE angle of 32.6° ± 6.8° [SD], mean anterior CE angle of 58.2° ± 8.1° [SD], mean femoral neck version of 17.1° ± 8.2° [SD]. Large alpha angle (>57°) and older age were both correlated with superior and posterosuperior labral tear incidence ( p < 0.05) and larger tear size ( p < 0.05). Furthermore, alpha angle is significantly correlated with superior labral tear incidence in young-age subgroup (age <45 years) ( p < 0.05), also significantly correlated with posterosuperior labral tear incidence and larger tear size in middle-age subgroup (45 ≤ age ≤ 60 years) ( p < 0.05).

CONCLUSION

A large alpha angle (>57°) is significantly correlated with increased incidence of superior and posterosuperior labral tear, and larger tear size in patients with hip pain, and the relationships depend on age.

Association of Chondrolabral Lesions with Ultrasound-Guided Detection of Pathological Head-Neck Contour

OBJECTIVE

This study aimed to investigate whether the asphericity of the neck-head junction of the femur confirmed via ultrasound is associated with further pathology due to femoro-acetabular impingement (FAI).

METHODOLOGY

After a clinical examination with positive FAI tests, an ultrasound examination of the hip was performed. In the case of asphericity, a quantitative ultrasound-assisted assessment of the hip was performed, followed by contrast-enhanced arthro-MRI with the question of cartilage or labral damage.

RESULTS AND CONCLUSIONS

We included 51 patients with a mean age of 35.25. According to the examination algorithm, asphericity was present in all patients via ultrasonography. The average anterior alpha angle (AAA) determined in ultrasonography was 43.49°. The average AAA on the arthro-MRI was 44.19°. The mean anterior head neck offset (AHNO) in ultrasound was 5.27 mm, and in arthro-MRI, it was 5.36 mm. Arthro-MRI confirmed a bump in 47 patients and a talization disorder in 4 patients. In 49 patients, a labral lesion was found, with one being a re-rupture. Furthermore, in one patient, labral degeneration was identified. Cartilage damage to the hip joint was found in 25 patients. Two patients had neither labral nor cartilage damage in the arthro-MRI. In our study, sonographically confirmed asphericity of the head-neck junction was found in 49 cases, which was associated with further pathology and, according to the current doctrine, was attributable to the FAI and required surgical intervention. This study shows that the detection of a pathologic head and neck contour via ultrasound in combination with positive clinical signs, as present in FAI, is associated with chondrolabral lesions detected via arthro-MRI in 96.1% of cases.

ACR Appropriateness Criteria® Chronic Hip Pain: 2022 Update

Chronic hip pain is a frequent chief complaint for adult patients who present for evaluation in a variety of clinical practice settings. Following a targeted history and physical examination, imaging plays a vital role in elucidating the etiologies of a patient's symptoms, as a wide spectrum of pathological entities may cause chronic hip pain. Radiography is usually the appropriate initial imaging test following a clinical examination. Depending on the clinical picture, advanced cross-sectional imaging may be subsequently performed for further evaluation. This documents provides best practice for the imaging workup of chronic hip pain in patients presenting with a variety of clinical scenarios. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Diagnostic value of magnetic resonance imaging and magnetic resonance arthrography for assessing acetabular labral tears: A systematic review and meta-analysis

BACKGROUND

This study aimed to systematically evaluate the value of magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA) in the diagnosis of acetabular labral tears.

METHODS

Databases including PubMed, Embase, Cochrane Library, Web of Science, CBM, CNKI, WanFang Data, and VIP were electronically searched to collect relevant studies on magnetic resonance in the diagnosis of acetabular labral tears from inception to September 1, 2021. Two reviewers independently screened the literature, extracted data, and assessed the risk of bias in the included studies by using the Quality Assessment of Diagnostic Accuracy Studies 2 tool. RevMan 5.3, Meta Disc 1.4, and Stata SE 15.0 were used to investigate the diagnostic value of magnetic resonance in patients with acetabular labral tears.

RESULTS

A total of 29 articles were included, involving 1385 participants and 1367 hips. The results of the meta-analysis showed that the pooled sensitivity, pooled specificity, pooled positive likelihood ratio, pooled negative likelihood ratio, pooled diagnostic odds ratio, area under the curve of the summary receiver operating characteristic, and Q* of MRI for diagnosing acetabular labral tears were 0.77 (95% confidence interval [CI], 0.75-0.80), 0.74 (95% CI, 0.68-0.80), 2.19 (95% CI, 1.76-2.73), 0.48 (95% CI, 0.36-0.65), 4.86 (95% CI, 3.44-6.86), 0.75, and 0.69, respectively. The pooled sensitivity, pooled specificity, pooled positive likelihood ratio, pooled negative likelihood ratio, pooled diagnostic odds ratio, area under the curve of the summary receiver operating characteristic, and Q* of MRA for diagnosing acetabular labral tears were 0.87 (95% CI, 0.84-0.89), 0.64 (95% CI, 0.57-0.71), 2.23 (95% CI, 1.57-3.16), 0.21 (95% CI, 0.16-0.27), 10.47 (95% CI, 7.09-15.48), 0.89, and 0.82, respectively.

CONCLUSION

MRI has high diagnostic efficacy for acetabular labral tears, and MRA has even higher diagnostic efficacy. Due to the limited quality and quantity of the included studies, the above results should be further validated.

Acetabular paralabral cysts demonstrating perineural propagation

OBJECTIVE

Acetabular paralabral cysts are common and are almost always associated with labral tears. Uncommonly, they extend into the periacetabular soft tissues or may propagate along peripheral nerves causing pain and hip dysfunction. The aim was to evaluate the clinical and MRI presentations of such cases including perineural propagation.

METHODS

Retrospective cross-sectional study with a search of electronic health records for cases of acetabular paralabral cysts demonstrating perineural propagation was performed. Clinical and MR imaging features were tabulated after re-review by experienced musculoskeletal radiologists, and available outcomes were recorded. Descriptive statistics were performed.

RESULTS

14 cases were recorded. The mean age was 56.9 years (range = 30-79 years) and female:male ratio was 1:2.6. The commonest presenting complaint was hip pain (10/14, 71.4%). Other complaints included groin pain, perineal pain and hip dysfunction. No symptoms were attributed to the acetabular paralabral cyst in 3/14 patients (21.4%). None had foot drop. The cysts were multilocular in all cases and were homogenously T2 hyperintense in 13/14 (92.9%). Labral tears were identified in 11/14 cases (78.6%). The sciatic nerve was most commonly involved in 5/14 cases (35.7%) with the obturator, medial femoral cutaneous nerve, femoral nerve, superior and inferior gluteal nerves also affected.No intervention was undertaken in 9/14 cases (64.3%). 5/14 (35.7%) underwent image guided aspiration and corticosteroid injection. 4/5 such patients reported reduced pain following the procedure.

CONCLUSION

Paralabral cysts demonstrating perineural propagation are uncommon and exhibit varied presentations. Most patients who underwent image-guided or surgical interventions reported an improvement in symptoms.

ADVANCES IN KNOWLEDGE.

This is the first description of a series of patients with acetabular paralabral cysts demonstrating perineural propagation in the literature. A comprehensive description of their clinical and imaging characteristics and interventions/outcomes where relevant is provided.

Quantitative and Qualitative Ultrasound Evaluation for the Diagnosis of an Anterosuperior Acetabular Labral Tear

We investigated the diagnostic performance of qualitative and quantitative ultrasound criteria for anterosuperior acetabular labral tears (ALTs). In all, 118 people with ALTs (120 hips; case group) and 31 asymptomatic volunteers (42 hips; control group) at Peking University Third Hospital between August 2018 and November 2019 were consecutively included. The labral cleft, labral heterogeneous echogenicity, labral plump morphology, paralabral cyst and labral focal hyperechoic area were used as the qualitative criteria. The anterosuperior labral cross-section area (CSA) was measured as the quantitative criterion. The diagnostic utility of the quantitative and qualitative criteria were explored with magnetic resonance imaging as the diagnostic gold standard. Labral heterogeneous echogenicity was the most sensitive criterion for diagnosing ALTs (up to 80.00%), and the specificity of diagnosing ALTs with paralabral cysts, labral focal hyperechoic area and subcortical cysts of the femoral head and neck was as high as 90.48%-100%. The labral CSA in the case group was 0.27 cm² (0.21-0.39 cm²), which was significantly larger compared with the control group (0.18 cm² [0.14-0.23 cm²]; p < 0.001). The area under the receiver operating characteristic curve was 0.802 for diagnosing ALTs according to the labral CSA. The sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy of the combined qualitative criteria for diagnosing ALTs were 90.00%, 71.43%, 90.00%, 71.43% and 85.19%, respectively. Labral heterogeneous echogenicity is a sensitive criterion for diagnosing ALTs, and paralabral cysts, labral focal hyperechoic, area and subcortical cysts of the femoral head and neck are specific criteria. The CSA of the anterosuperior acetabular labrum measured by ultrasound can be used as a quantitative criterion to diagnose ALTs. The combination of labral qualitative criteria provides higher sensitivity and accuracy in diagnosing ALTs.

Prevalence of sacroiliitis among patients referred for hip MR arthrography

OBJECTIVE

To determine the prevalence of sacroiliitis among patients who have been referred for MR arthrography.

MATERIALS AND METHODS

A retrospective search identified 130 consecutive MR arthrograms of the hip performed on a 1.5T Siemens Avanto at our institution from August 2013 to August 2014. Four studies were excluded due to the absence of a coronal short tau inversion recovery sequence of the pelvis, leaving 126 studies for analysis. A musculoskeletal radiology fellow and three attending musculoskeletal radiologists reviewed the images for the presence of bone marrow edema affecting the sacroiliac joints. Only cases of bone marrow edema meeting the Assessment of SpondyloArthritis international Society definition were considered positive. The two-tailed Fisher's exact test was used to compare the prevalence of positive MRI findings among age and gender groups. GraphPad InStat (GraphPad Software) was used for statistical calculations.

RESULTS

Patients less than 40 years of age demonstrated a statistically higher prevalence of positive MRI findings of sacroiliitis when compared to patients older than 40 (p = 0.0082). No difference in prevalence was found between genders. Overall prevalence of MRI signal alteration suggestive of sacroiliitis as defined by the Assessment of SpondyloArthritis international Society was 4.8%. Among the six patients with positive findings, two were subsequently diagnosed with spondyloarthritis.

CONCLUSION

Hip pain may be a presenting symptom of spondyloarthritis and attention should be paid to the sacroiliac joints during screening examinations, particularly in patients less than 40 years of age.

Magnetic Resonance Arthrogram Improves Visualization of Hip Capsular Defects in Patients Undergoing Previous Hip Arthroscopy

Purpose

To compare magnetic resonance imaging (MRI) with magnetic resonance arthrogram (MRA) in the identification of hip capsular defects in patients who previously underwent hip arthroscopy.

Methods

Patients who underwent revision hip arthroscopy for capsular insufficiency by a single surgeon between March 2014 and December 2019 were identified by Current Procedural Terminology code. Patients with arthroscopically confirmed capsular defects treated surgically who underwent both MRI and MRA between their primary and revision surgeries were identified. Imaging studies were blinded, randomized, and distributed to two fellowship-trained musculoskeletal radiologists. Radiologists evaluated 14 components of different anatomic structures, including the presence of capsular defect and defect grading, over 2 months, with a 2-week washout period between 4 sets of reads to obtain 2 complete reads from each radiologist. Data were analyzed in R version 4.0.2.

Results

Two hundred thirty patients underwent revision hip arthroscopy between March 2014 and December 2019. Twelve patients had both an MRI and an MRA of the operated hip performed between their primary and revision surgeries. Time between primary and revision hip arthroscopy was 2.0 ± 1.5 years (R: .3-6.3). Time between MRI and MRA was .6 ± .6 years (R: .0-1.6). Sensitivity for detecting hip capsular defects was significantly higher for MRA than for MRI (87.5%, 95% CI: [68,96] vs 50%, 95% CI: [31,69], respectively; P = .008).

Conclusions

This retrospective review demonstrates that MRA has higher sensitivity than MRI in detecting surgically confirmed capsular defects. MRA may be more helpful in identifying capsular defects in patients presenting with hip instability symptoms who have had a previous hip arthroscopy.

Level of Evidence

Level IV, diagnostic case series.

3.0 T MRI is more recommended to detect acetabular labral tears than MR Arthrography: an updated meta-analysis of diagnostic accuracy

Background

This meta-analysis aimed to evaluate the current evidence on the diagnostic performance of MRI/MRA for detecting acetabular labral tears (ALT).

Methods

We systematically searched the PubMed, Embase, and Cochrane library until February 5, 2021, to identify original research studies reporting the diagnostic performance of MRI/MRA for the detection of ALT. Study methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS-2) tool. The summary sensitivity (Se) and specificity (Sp) of the studies were estimated using a bivariate model. We calculated the post-test probability to assess the clinical utility of MRI/MRA. Univariate meta-regression and subgroup analyses were performed to assess between-study heterogeneity.

Results

We included 22 studies (n = 1670 patients). The meta-analytic summary Se and Sp for MRI were 0.8 (95% CI 0.51–0.94) and 0.77 (95% CI 0.68–0.84), respectively, while for MRA they were 0.89 (95% CI 0.82–0.93) and 0.69 (95% CI 0.56–0.80). MRA showed a higher area under the summary receiver operating curve (SROC) (0.87 vs. 0.80) than MRI. MRI could increase the post-test probability to 0.78 and could decrease the post-test probability to 0.21, MRA could increase the post-test probability to 0.74 and could decrease the post-test probability to 0.14. Meta-regression analysis showed two significant factors affecting study heterogeneity: MR field strength and reference standard. After dividing the studies into two subgroups based on the MR field strength, we found that the Se values of 3.0 T MRI were very close to MRA (0.87 vs. 0.89), the Sp values of 3.0 T MRI were superior to MRA (0.77 vs. 0.69).

Conclusions

Given that 3.0 T MRI could provide a non-invasive, fast and convenient method to recognize suspicious ALT cases, 3.0 T MRI is more recommended than MRA.

The Short-term Outcomes of Physiotherapy for Patients with Acetabular Labral Tears: An Analysis according to Severity of Injury in Magnetic Resonance Imaging

Purpose

The aim of this study was to evaluate the short-term outcome of physiotherapy in patients with acetabular labral tears and to assess the effectiveness of physiotherapy according to the severity of the labral tear.

Materials and Methods

Thirty-five patients who underwent physiotherapy for treatment of symptomatic acetabular labral tears were enrolled. We evaluated the severity of the acetabular labral tears, which were classified based on the Czerny classification system using 3-T MRI. Clinical findings of microinstability and extra-articular pathologies of the hip joint were also examined. The International Hip Outcome Tool 12 (iHOT12) was use for evaluation of outcome scores pre- and post-intervention.

Results

The mean iHOT12 score showed significant improvement from 44.0 to 73.6 in 4.7 months. Compared with pre-intervention scores, significantly higher post-intervention iHOT12 scores were observed for Czerny stages I and II tears (all P<0.01). However, no significant difference was observed between pre-intervention and post-intervention iHOT12 scores for stage III tears (P=0.061). In addition, seven patients (20.0%) had positive microinstability findings and 22 patients (62.9%) had findings of extra-articular pathologies. Of the 35 patients, eight patients (22.9%) underwent surgical treatment after failure of conservative management; four of these patients had Czerny stage III tears.

Conclusion

The iHOT12 score of patients with acetabular labral tears was significantly improved by physiotherapy in the short-term period. Improvement of the clinical score by physiotherapy may be poor in patients with severe acetabular labral tears. Determining the severity of acetabular labral tears can be useful in determining treatment strategies.

Assessment of acetabular chondral damage and labral pathologies via direct MR arthrography: specialization matters

AIMS

To compare the diagnostic accuracy of investigators from different specialities (radiologists and orthopaedic surgeons) with varying levels of experience of 1.5 T direct magnetic resonance arthrography (dMRA) against intraoperative findings in patients with femoroacetabular impingement syndrome (FAIS).

METHODS

A total of 272 patients were evaluated with dMRA and subsequent hip arthroscopy. The dMRA images were evaluated independently by two non-hip-arthroscopy-trained orthopaedic surgeons, two fellowship-trained musculoskeletal radiologists, and two hip-arthroscopy-trained orthopaedic surgeons. The radiological diagnoses were compared with the intraoperative findings.

RESULTS

Hip arthroscopy revealed labral pathologies in 218 (79%) and acetabular chondral lesions in 190 (69%) hips. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy for evaluating the acetabular labral pathologies were 79%, 18%, 79%, 18%, and 66% (non-hip-arthroscopy trained orthopaedic surgeons), 83%, 36%, 83%, 36%, and 74% (fellowship-trained musculoskeletal radiologists), and 88%, 53%, 88%, 54% and 81% (hip-arthroscopy trained orthopaedic surgeons). The sensitivity, specificity, PPV, NPV and accuracy of dMRA for assessing the acetabular chondral damage were 81%, 36%, 71%, 50%, and 66% (non-hip-arthroscopy trained orthopaedic surgeons), 84%, 38%, 75%, 52%, and 70% (fellowship-trained musculoskeletal radiologists), and 91%, 51%, 81%, 73%, and 79% (hip-arthroscopy trained orthopaedic surgeons). The hip-arthroscopy trained orthopaedic surgeons displayed the highest percentage of correctly diagnosed labral pathologies and acetabular chondral lesions, which is significantly higher than the other two investigator groups (p < 0.05).

CONCLUSION

The accuracy of dMRA on detecting labral pathologies or acetabular chondral lesions depends on the examiner and its level of experience in hip arthroscopy. The highest values are found for the hip-arthroscopy-trained orthopaedic surgeons.

LEVEL OF EVIDENCE

Retrospective cohort study; III.

Complications of hip preserving surgery

Preoperative evaluation of the pathomorphology is crucial for surgical planning, including radiographs as the basic modality and magnetic resonance imaging (MRI) and case-based additional imaging (e.g. 3D-CT, abduction views).

Hip arthroscopy (HAS) has undergone tremendous technical advances, an immense increase in use and the indications are getting wider. The most common indications for revision arthroscopy are labral tears and residual femoroacetabular impingement (FAI).

Treatment of borderline developmental dysplastic hip is currently a subject of controversy. It is paramount to understand the underlining problem of the individual hip and distinguish instability (dysplasia) from FAI, as the appropriate treatment for unstable hips is periacetabular osteotomy (PAO) and for FAI arthroscopic impingement surgery.

PAO with a concomitant cam resection is associated with a higher survival rate compared to PAO alone for the treatment of hip dysplasia. Further, the challenge for the surgeon is the balance between over- and undercorrection.

Femoral torsion abnormalities should be evaluated and evaluation of femoral rotational osteotomy for these patients should be incorporated to the treatment plan.

Cite this article: EFORT Open Rev 2021;6:472-486. DOI: 10.1302/2058-5241.6.210019

Comparison of 2D, 3D, and radially reformatted MR images in the detection of labral tears and acetabular cartilage injury in young patients

OBJECTIVE

The purpose of this study was to compare the utility of two-dimensional high-resolution (2D), 3-dimensional with multiplanar reconstruction (3D MPR), and radially reformatted (RR) MRIs when evaluating the complexities of the hip joint in patients with femoroacetabular impingement (FAI). We hypothesized RR would be superior in detecting labral pathology and 2D would be superior in detecting transition zone and acetabular cartilage injury.

MATERIALS AND METHODS

2D, 3D MPR, and RR MRIs of 33 patients, who later underwent surgical treatment for FAI, were evaluated for sensitivity, specificity, and accuracy. Bland-Altman methods were used to estimate agreement between each method and the gold-standard, arthroscopic visualization of the hip joint, regarding the percentage of the hip joint affected by each injury type.

RESULTS

3D MPR and RR groupings were associated with the highest sensitivity and accuracy for labral injury. 3D MPR demonstrated the smallest bias in assessing the percentage of joint affected by labral injury and was the most accurate in identifying acetabular cartilage injury, whereas RR had the smallest mean difference in assessing the percentage of joint affected by acetabular cartilage injury. 2D was the most accurate in identifying transition zone injuries, while RR was superior in assessing the percentage of the joint affected by transition zone injury.

CONCLUSIONS

Our results suggest that including both 3D MPR and RR MRI groupings is favorable for accurate joint visualization and well-informed treatment planning, especially given that labral injury is a main source of pain and dysfunction for FAI patients.

Best Practices: Hip Femoroacetabular Impingement

OBJECTIVE. Imaging plays a critical role in the assessment of patients with femoroacetabular impingement (FAI). With better understanding of the underlying pathomechanics and advances in joint-preserving surgery, there is an increasing need to define the most appropriate imaging workup. The purpose of this article is to provide guidance on best practices for imaging of patients with FAI in light of recent advances in corrective FAI surgery. CONCLUSION. Pelvic radiography with dedicated hip projections is the basis of the diagnostic workup of patients with suspected FAI to assess arthritic changes and acetabular coverage and to screen for cam deformities. Chondrolabral lesions should be evaluated with unenhanced MRI or MR arthrography. The protocol should include a large-FOV fluid-sensitive sequence to exclude conditions that can mimic or coexist with FAI, radial imaging to accurately determine the presence of a cam deformity, and imaging of the distal femoral condyles for measurement of femoral torsion. CT remains a valuable tool for planning of complex surgical corrections. Advanced imaging, such as 3D simulation, biochemical MRI, and MR arthrography with application of leg traction, has great potential to improve surgical decision-making. Further research is needed to assess the added clinical value of these techniques.

Microinstability of the hip: a systematic review of the imaging findings

OBJECTIVES

To undertake a systematic review of the morphologic features associated with hip microinstability and determine whether there are suggestive or diagnostic imaging findings.

METHODS

Four electronic databases were searched up to September 2019 to identify original research reporting morphologic features in individuals with either a clinical diagnosis of hip microinstability (instability without overt subluxation/dislocation) or those with symptomatic laxity demonstrated on imaging (increased femoral head translation/distraction or capsular volume). Studies focussing on individuals with pre-existing hip conditions (including definite dysplasia (lateral centre edge angle < 20°), significant trauma, previous dislocation or surgery were excluded. Methodological quality was assessed by the Quality Assessment of Diagnostic Accuracy Studies 2 tool.

RESULTS

Twenty-two studies met inclusion criteria (clinical diagnosis of microinstability n = 15 and demonstration of laxity n = 7). Imaging information gathered from the studies includes radiographs (n = 14), MRI (n = 6), MR arthrography (n = 4), CT (n = 1) and intraoperative examination. Most studies exhibited design features associated with an overall high or unclear risk of bias. Some dysplastic features are associated with microinstability or laxity reference measures; however, microinstability is frequently diagnosed in those with a lateral centre edge angle > 25°. Other associated imaging findings reported include impingement morphology, anterior labral tearing, femoral head chondral injury, ligamentum teres tears and capsular attenuation.

CONCLUSIONS

The current literature does not provide strong evidence for imaging features diagnostic of microinstability. In the appropriate clinical context, dysplastic morphology, anterior labral tears and ligamentum teres tears may be suggestive of this condition although further research is needed to confirm this.

PROSPERO REGISTRATION

CRD42019122406.

Hip preservation

Classical indications for hip preserving surgery are: femoro-acetabular impingement (FAI) (intra- and extra-articular), hip dysplasia, slipped capital femoral epiphysis, residual deformities after Perthes disease, avascular necrosis of the femoral head.

Pre-operative evaluation of the pathomorphology is crucial for surgical planning including radiographs as the basic modality and magnetic resonance imaging (MRI) and/or computed tomography (CT) to evaluate further intra-articular lesions and osseous deformities.

Two main mechanisms of intra-articular impingement have been described:

(1) Inclusion type FAI (‘cam type’).

(2) Impaction type FAI (‘pincer type’).

Either arthroscopic or open treatment can be performed depending on the severity of deformity.

Slipped capital femoral epiphysis often results in a cam-like deformity of the hip. In acute cases a subcapital re-alignment (modified Dunn procedure) of the femoral epiphysis is an effective therapy.

Perthes disease can lead to complex femoro-acetabular deformity which predisposes to impingement with/without joint incongruency and requires a comprehensive diagnostic workup for surgical planning.

Developmental dysplasia of the hip results in a static overload of the acetabular rim and early osteoarthritis. Surgical correction by means of periacetabular osteotomy offers good long-term results.

Cite this article: EFORT Open Rev 2020;5:630-640. DOI: 10.1302/2058-5241.5.190074

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.

Does gadolinium improve magnetic resonance arthrography of the hip beyond fluid distension alone?

AIM

To determine if there is a difference in the detection of labral tears and cartilage lesions using the T2-weighted sequences of magnetic resonance arthrography (MRA) only, which simulate MRA with saline alone, compared with the full examination including T1-weighted sequences.

MATERIALS AND METHODS

One hundred hip MRA examinations performed at 3 T were identified retrospectively. Each study was reviewed by a musculoskeletal radiologist using either the T2-weighted sequences only (without gadolinium-based contrast agent [GBCA] effect) or the entire examination, including T1-weighted sequences (with GBCA effect). Receiver operating characteristic (ROC) curves were calculated for both groups and compared within a non-inferiority framework, using - 0.10 as the limit of non-inferiority.

RESULTS

For labral tears, the difference area under the curve (AUC) was -0.004 (95% confidence interval [CI]: -0.064-0.056, p=0.90). For acetabular cartilage lesions, the difference AUC was 0.011 (95% CI: -0.073-0.096, p=0.79). For femoral cartilage lesions, the difference AUC was -0.059 (95% CI: -0.206-0.087, p=0.43).

CONCLUSION

T2-weighted sequences alone were not inferior in diagnostic accuracy compared with the full examination (including T1-weighted sequences with intra-articular GBCA) in detecting acetabular cartilage lesions and labral tears. Further study with prospective comparison of saline injectate to GBCA-containing injectate may help clarify the necessity of continued GBCA use in MRA of the hip.

Value of response to anesthetic injection during hip MR arthrography to differentiate between intra- and extra-articular pathology

PURPOSE

To determine the value of anesthetic injection during hip MR arthrography (anesthetic MRA) to differentiate between intra- and extra-articular pathology in patients with hip pain.

MATERIALS AND METHODS

This retrospective study was IRB-approved and HIPAA-compliant. We included 75 consecutive adult patients (46 women, mean age 38 ± 13 years) who were referred for MRA. All patients underwent a focused hip examination including active flexion, passive flexion, and passive flexion with internal and external rotation, immediately prior to injection. Anesthetic MRA was performed following fluoroscopically guided intra-articular injection of contrast mixed with anesthetic. Following the injection, the hip examination was repeated, and the pain response was recorded. Clinical records, including response to corticosteroid injections, physical therapy notes, and operative reports were reviewed for verification of intra- and extra-articular pathology as the source of hip pain (gold standard). The positive (PPV) and negative predictive values (NPP) of anesthetic MRA to differentiate between intra- and extra-articular pathology were calculated.

RESULTS

On MRI, 41 patients had only intra-articular and 5 patients only extra-articular pathology, while 29 patients had both, intra- and extra-articular pathology. Forty-three patients had pain relief and 32 patients had no pain relief after anesthetic injection. PPV of anesthetic MRA to detect intra-articular pathology was 91% and NPV was 67%.

CONCLUSION

Anesthetic MRA can be used as an adjunct to define the origin of hip pain. A positive response suggests intra-articular pathology which can be helpful to localize the source of pain in equivocal cases where both intra- and extra-articular pathology are evident on MRI.

Validity of direct magnetic resonance arthrogram in patients with femoroacetabular impingement and their outcome post hip arthroscopy

Femoroacetabular Impingement is an established cause of labral tears and chondral delamination. The aim was to test the validity of direct magnetic resonance arthrogram [dMRA] in the diagnosis of the same. We also looked at the short term functional outcome in these patients post hip arthroscopy. The dMRA is valuable in diagnosing labral tears nevertheless poor in detecting cartilage delamination. Hip arthroscopic intervention provided a good short-term functional outcome; however, should be offered with caution in patients over 40 years. To our knowledge, this is the single largest series published with similar methodology.

Validity of Magnetic Resonance Imaging Measurement of Hip Labral Width Compared With Intraoperative Assessment

PURPOSE

To determine if magnetic resonance angiography (MRA) and/or magnetic resonance imaging (MRI) could accurately determine the width of the labrum.

METHODS

Consecutively enrolled patients between the ages of 18 and 65 indicated for hip arthroscopy for femoroacetabular impingement were included between December 2017 and June 2018. Inclusion criteria for preoperative MRIs included: MRI availability in picture archiving and communication system; performance on a 1.5T or 3T MRI or 3T MRA; and adequate quality and lack of labrum ossification. Intraoperative labral width measurements were taken at standardized locations using an established acetabular "clockface" paradigm. Measurement was performed using a calibrated probe. The labral width was defined as the distance from the labrum extended laterally from the acetabular rim. MRI measurements were taken by 2 blinded musculoskeletal fellowship-trained radiologists at the same positions. Measurements were made at the 11:30 o'clock position (indirect rectus) on coronal proton density (PD) sequence, at 3 o'clock position (psoas-U) on axial oblique PD sequence, and at 1:30 (a point halfway between the 2) on sagittal fat-suppressed PD. The surgeons were blinded to the radiologists' measurements and vice versa. Intraoperative and radiographic labral width measurements were compared using an intraclass correlation coefficients (ICC), absolute agreement, and 2-way random effects model. The 2 radiologists' measurements were compared for interrater reliability using the same ICC model.

RESULTS

Fifty-one patients were included (30 females, 26 right hips). Average labrum width at the 3:00, 11:30, and 1:30 o'clock positions by arthroscopic measurement were 5.8 mm (range; standard deviation, 2-8; ±1.4), 6.3 mm (2-10; ±1.5) and 6.0 mm (2-9; ±1.5), and by MRI were 6.3 mm (2-10; ±1.5), 6.7 mm (3-10; ±1.4), and 6.1 mm (2-9; ±1.6), respectively. When including all MRI modalities, ICC agreement between intraoperative assessment, and radiologist assessment at the 3:00 o'clock, 11:30, and point halfway between was 0.82 (P < .001), 0.78 (P < .001), 0.84 (P < .001), respectively. Radiologist interrater ICC agreement at the same points was 0.88 (P < .001), 0.93 (P < .001), and 0.88 (P < .001).

CONCLUSIONS

Strong agreement was found between radiologic and arthroscopic measurement of labrum width when using MRI, suggesting MRI is an accurate way to measure labral width. There was not a significant difference between different MRI modalities. Accurately measuring labral width preoperatively with MRI may aid in surgical decision making.

LEVEL OF EVIDENCE

Level II, diagnostic study.

Magnetic Resonance Arthrography, a valuable pre-operative imaging modality in femoro-acetabular impingement

Background

The diagnostic accuracy of MR arthrography in preoperative assessment of labral tears and chondral abnormalities in femoroacetabular impingement patients.

A non-randomized control study including 31 FAI patients (17 male and 14 females, mean age 31.9 years). All patients underwent MR arthrography after US-guided intra-articular contrast injection. Conventional and MR arthrography images were evaluated for bone abnormalities (including alpha angle and acetabular depth measurements), labral tears, and chondral abnormalities. The results were correlated to arthroscopy as the gold standard. Sensitivity, specificity, PPV, and NPV in the detection of labral tears and chondral abnormalities were statistically calculated.

Results

The included FAI patients presented cam (mean age 30.4 years ± 6.8 years), pincer (mean age 33.6 years ± 9.8 years), and mixed (mean age 36.6 years ± 12.9 years) types with the predominance of cam type. Cam type predominated in the male, while pincer and mixed types predominated in female patients. MR arthrography detected 41 labral tears in 23 patients with 87.5%, 71.4%, 91.3%, and 62.5% sensitivity, specificity, PPV, and NPV, respectively, and detected chondral abnormalities in 13 patients with 66.7%, 92.3%, 92.3%, and 66.7% sensitivity, specificity, PPV, and NPV, respectively.

Conclusion

MR arthrography is a valuable imaging modality in preoperative assessment of FAI patients. Besides identifying the type of impingement through alpha angle and acetabular depth measurements, it detects labral tears with high sensitivity and PPV. Although less sensitive in detection of chondral abnormalities, our results showed high specificity.

Comparative reliability and diagnostic performance of conventional 3T magnetic resonance imaging and 1.5T magnetic resonance arthrography for the evaluation of internal derangement of the hip

Objective

To compare the diagnostic accuracy of conventional 3T MRI against 1.5T MR arthrography (MRA) in patients with clinical femoroacetabular impingement (FAI).

Methods

Sixty-eight consecutive patients with clinical FAI underwent both 1.5T MRA and 3T MRI. Imaging was prospectively analysed by two musculoskeletal radiologists, blinded to patient outcomes and scored for internal derangement including labral and cartilage abnormality. Interobserver variation was assessed by kappa analysis. Thirty-nine patients subsequently underwent hip arthroscopy and surgical results and radiology findings were analysed.

Results

Both readers had higher sensitivities for detecting labral tears with 3T MRI compared to 1.5T MRA (not statistically significant p=0.07). For acetabular cartilage defect both readers had higher statistically significant sensitivities using 3T MRI compared to 1.5T MRA (p=0.02). Both readers had a slightly higher sensitivity for detecting delamination with 1.5T MRA compared to 3T MRI, but these differences were not statistically significant (p=0.66). Interobserver agreement was substantial to perfect agreement for all parameters except the identification of delamination (3T MRI showed moderate agreement and 1.5T MRA substantial agreement).

Conclusion

Conventional 3T MRI may be at least equivalent to 1.5T MRA in detecting acetabular labrum and possibly superior to 1.5T MRA in detecting cartilage defects in patients with suspected FAI.

Key Points

• Conventional 3T MRI is equivalent to 1.5T MRA for diagnosing labral tears.

• Conventional 3T MRI is superior to 1.5T MRA for diagnosing acetabular cartilage defect.

• Conventional 3T MRI is equivalent to 1.5T MRA for diagnosing cartilage delamination.

• Symptom severity score was significantly higher (p<0.05) in group proceeding to surgery.

Diagnostic Accuracy of Imaging Modalities and Injection Techniques for the Diagnosis of Femoroacetabular Impingement/Labral Tear: A Systematic Review With Meta-analysis

BACKGROUND

Diagnosing femoroacetabular impingement/acetabular labral tear (FAI/ALT) and subsequently making a decision regarding surgery are based primarily on diagnostic imaging and intra-articular hip joint injection techniques of unknown accuracy.

PURPOSE

Summarize and evaluate the diagnostic accuracy and clinical utility of various imaging modalities and injection techniques relevant to hip FAI/ALT.

STUDY DESIGN

Systematic review with meta-analysis.

METHODS

A computer-assisted literature search was conducted of MEDLINE, CINAHL, and EMBASE databases using keywords related to diagnostic accuracy of hip joint pathologic changes. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines were used for the search and reporting phases of the study. Quality assessment of bias and applicability was conducted using the Quality of Diagnostic Accuracy Studies (QUADAS) tool. Random effects models were used to summarize sensitivities (SN), specificities (SP), likelihood ratios (+LR and -LR), diagnostic odds ratios (DOR), and respective confidence intervals (CI).

RESULTS

The search strategy and assessment for risk of bias revealed 25 articles scoring above 10/14 on the items of the QUADAS. Four studies investigated FAI, and the data were not pooled. Twenty articles on ALT qualified for meta-analysis. Pretest probability of ALT in the studies in this review was 81% (72%-88%), while the pretest probability of FAI diagnosis was 74% (95% CI, 51%-91%). The meta-analysis showed that computed tomography arthrography (CTA) demonstrated the strongest overall diagnostic accuracy: pooled SN 0.91 (95% CI, 0.83-0.96); SP 0.89 (95% CI, 0.74-0.97); +LR 6.28 (95% CI, 2.78-14.21); -LR 0.11 (95% CI, 0.06-0.21); and DOR 64.38 (95% CI, 19.17-216.21).

CONCLUSION

High pretest probability of disease was demonstrated. Positive imaging findings increased the probability that a labral tear existed by a minimal to small degree with the use of magnetic resonance imaging/magnetic resonance angiogram (MRI/MRA) and ultrasound (US) and by a moderate degree for CTA. Negative imaging findings decreased the probability that a labral tear existed by a minimal degree with the use of MRI and US, a small to moderate degree with MRA, and a moderate degree with CTA.

CLINICAL RELEVANCE

Although findings of the included studies suggested potentially favorable use of these modalities for the diagnosis of ALT and FAI, our results suggest that these findings have limited generalizability and clinical utility given very high pretest prevalence, large confidence intervals, and selection criteria of the studies. Registration: PROSPERO Registration #CRD42015027745.

Hip Imaging in Athletes: Sports Imaging Series

Hip or groin pain in athletes is common and clinical presentation is often nonspecific. Imaging is a very important diagnostic step in the work-up of athletes with hip pain. This review article provides an overview on hip biomechanics and discusses strategies for hip imaging modalities such as radiography, ultrasonography, computed tomography, and magnetic resonance (MR) imaging (MR arthrography and traction MR arthrography). The authors explain current concepts of femoroacetabular impingement and the problem of high prevalence of cam- and pincer-type morphology in asymptomatic persons. With the main focus on MR imaging, the authors present abnormalities of the hip joint and the surrounding soft tissues that can occur in athletes: intraarticular and extraarticular hip impingement syndromes, labral and cartilage disease, microinstability of the hip, myotendinous injuries, and athletic pubalgia. (©) RSNA, 2016.

Accuracy of non-arthrographic 3T MR imaging in evaluation of intra-articular pathology of the hip in femoroacetabular impingement

OBJECTIVE

To investigate the accuracy of non-arthrographic 3-T MRI compared to hip arthroscopy in the assessment of labral and cartilaginous pathology in patients with suspected FAI.

MATERIALS AND METHODS

Following IRB approval and waived consent, 42 consecutive cases of suspected FAI with non-arthrographic 3-T MRI and arthroscopy of the hip were reviewed. High-resolution TSE MR imaging was evaluated in consensus by two musculoskeletal radiologists, blinded to arthroscopic findings, for the presence of labral tears and articular cartilage lesions. Acetabular cartilage was categorized as normal, degeneration/fissuring, delamination, or denudation. MRI findings were compared to arthroscopy. Sensitivity, specificity, accuracy, and predictive values for MRI were calculated using arthroscopy as the standard of reference.

RESULTS

Forty-two hips in 38 patients with a mean age of 29 (range 13-45 years) were assessed. Mean interval between MRI and arthroscopy was 154 days (range 27-472 days). MRI depicted 41 cases with labral tears (sensitivity 100%, specificity 50%, accuracy 98%, PPV 98%, NPV 100%), 11 cases with femoral cartilage abnormalities (sensitivity 85%, specificity 100%, accuracy 95%, PPV 100%, NPV 94%), and 36 cases with acetabular cartilage lesions (sensitivity 94% specificity 67%, accuracy 90%, PPV 94%, NPV 67%). Of the 36 cases with acetabular cartilage lesions on MRI, 7 were characterized as degeneration/fissuring, 26 as delamination, and 3 as denudation, with discordant results between MRI and arthroscopy for grading of articular cartilage in ten cases.

CONCLUSION

Non-arthrographic 3-T MR imaging is a highly accurate technique for evaluation of the labrum and cartilage in patients with clinically suspected FAI.

Accuracy of magnetic resonance studies in the detection of chondral and labral lesions in femoroacetabular impingement: systematic review and meta-analysis

BACKGROUND

Several types of Magnetic resonance imaging (MRI) are commonly used in imaging of femoroacetabular impingement (FAI), however till now there are no clear protocols and recommendations for each type. The aim of this meta-analysis is to detect the accuracy of conventional magnetic resonance imaging (cMRI), direct magnetic resonance arthrography (dMRA) and indirect magnetic resonance arthrography (iMRA) in the diagnosis of chondral and labral lesions in femoroacetabular impingement (FAI).

METHODS

A literature search was finalized on the 17th of May 2016 to collect all studies identifying the accuracy of cMRI, dMRA and iMRA in diagnosing chondral and labral lesions associated with FAI using surgical results (arthroscopic or open) as a reference test. Pooled sensitivity and specificity with 95% confidence intervals using a random-effects meta-analysis for MRI, dMRA and iMRA were calculated also area under receiver operating characteristic (ROC) curve (AUC) was retrieved whenever possible where AUC is equivocal to diagnostic accuracy.

RESULTS

The search yielded 192 publications which were reviewed according inclusion and exclusion criteria then 21 studies fulfilled the eligibility criteria for the qualitative analysis with a total number of 828 cases, lastly 12 studies were included in the quantitative meta-analysis. Meta-analysis showed that as regard labral lesions the pooled sensitivity, specificity and AUC for cMRI were 0.864, 0.833 and 0.88 and for dMRA were 0.91, 0.58 and 0.92. While in chondral lesions the pooled sensitivity, specificity and AUC for cMRI were 0.76, 0.72 and 0.75 and for dMRA were 0.75, 0.79 and 0.83, while for iMRA were sensitivity of 0.722 and specificity of 0.917.

CONCLUSIONS

The present meta-analysis showed that the diagnostic test accuracy was superior for dMRA when compared with cMRI for detection of labral and chondral lesions. The diagnostic test accuracy was superior for labral lesions when compared with chondral lesions in both cMRI and dMRA. Promising results are obtained concerning iMRA but further studies still needed to fully assess its diagnostic accuracy.

Magnetic resonance arthrography and the prevalence of acetabular labral tears in patients 50 years of age and older

OBJECTIVE

Arthroscopy for acetabular labral tears has minimal impact on pain and function in older patients, especially in the setting of concomitant osteoarthritis. Still, many physicians seek this diagnosis with MR arthrography. Our purpose is to assess the frequency of acetabular labral tears in older patients with hip pain and correlate likelihood of labral pathology with severity of osteoarthritis as visualized on conventional radiograph.

MATERIALS AND METHODS

From 2004 to 2013, 208 hip MRI arthrograms and corresponding radiographs on patients aged 50 years and older were identified. Age, gender, grade and location of labral tear, alpha angle, Tönnis grade, and joint space width were documented. Labral tears and alpha angle were identified and measured on MR arthrogram. Tönnis grade and joint space width were measured on radiographs.

RESULTS AND CONCLUSIONS

On MR arthrography, true labral tearing was identified in 73 % of patients. There was some degree of labral pathology in 93.3 % of patients, and this increased to 100 % in patients with moderate to severe osteoarthritis, as defined by Tönnis grade 2-3 or joint space width ≤ 2 mm. There were no statistically significant correlations between labral tear grade and Tönnis grade or joint space width. Given the high frequency of labral pathology and the questionable efficacy of arthroscopic surgical intervention in older patients, MR arthrography should be primarily for those with minimal arthritis on radiograph and potential to benefit from surgery. If further imaging beyond radiographs is necessary in these patients, standard MRI may be a more appropriate imaging tool.

Magnetic resonance arthrography of the hip: prevalence of diagnoses not suspected by the referring physician and correlation with clinical examination and pain score

BACKGROUND

Magnetic resonance arthrography (MRA) of the hip is the most sensitive imaging modality for intra-articular pathologies such as labral tears.

PURPOSE

To evaluate the prevalence of non-suspected pathologies revealed by hip MRA and correlate them to physical examination/pain level.

MATERIAL AND METHODS

All hip MRAs (2011-2013) were retrospectively evaluated for intra- and extra-articular pathologies in consensus by two readers. A clinical score (0-7)/pain score (0-10) was calculated for each patient based on orthopedic test results extracted from referral forms/a telephone questionnaire. Patients were divided into four groups according to MRA findings: intra-articular expected (targeted) pathology only; intra-articular targeted and additional non-targeted (unexpected) pathology; non-targeted pathology; and no pathology. Pathologies prevalence/clinical score/pain score were compared between the groups.

RESULTS

A total of 229 MRAs were included (127 men, 102 women; mean age, 36.5 ± 14.17 years): 111(48.4%) patients had solely intra-articular targeted pathology. Significant non-targeted pathologies were detected in 76 (33%) patients (targeted and non-targeted, 51; non-targeted only 25). No significant pathology was detected in 42 patients (18%). Mean physical examination score was 2.77 ± 1.77, range 0-7. There was no significant difference or correlation (r = 0.017, P = 0.804) between the clinical scores of the different MRA pathology groups. Pain score (143 patients) was significantly higher in the non-targeted pathology group compared to the targeted and non-targeted group (P = 0.04) and to the no pathology group (P = 0.04). There was no correlation between the physical examination score and the pain score (r = 0.017, P = 0.804).

CONCLUSION

Unsuspected non-targeted pathologies were detected in 33% of hip MRA. Physical examination/pain level could not differentiate between patients.

Imaging in Hip Arthroscopy for Femoroacetabular Impingement: A Comprehensive Approach

Hip arthroscopy has experienced unprecedented growth in recent years and remains an area of booming technology and interest in orthopedic surgery. As understanding of the pathologic state of femoroacetabular impingement (FAI) has grown, imaging modalities have increased. Careful consideration of all bony and soft tissue structures in concert with physical examination findings in nonarthritic patients is necessary before any surgical intervention. This article summarizes the authors' approach to imaging in patients suspected of FAI, which facilitates careful patient selection and preoperative planning.

MRI of Labral and Chondral Lesions of the Hip

OBJECTIVE

Unenhanced MRI, indirect MR arthrography, and direct MR arthrography have been used in the radiologic evaluation of patients with suspected labral tears and chondral lesions of the hip. The purpose of this article is to examine the existing evidence for the use of these techniques in patients with hip pain and suspected labral or chondral abnormalities.

CONCLUSION

Evidence from a review of the radiologic literature supports the use of direct MR arthrography over unenhanced MRI and indirect MR arthrography for the detection of labral and cartilage abnormalities in the hip. Although high-resolution unenhanced 3-T MRI appears promising, limited information in the literature supports its use in the detection and characterization of chondrolabral lesions.

Use of MR arthrography in detecting tears of the ligamentum teres with arthroscopic correlation

OBJECTIVE

To demonstrate the normal appearance of the ligamentum teres on MR arthrography (MRA) and evaluate the accuracy of MRA in detecting ligamentum teres tears with arthroscopic correlation.

MATERIALS AND METHODS

Institutional Review Board approval was obtained with a waiver for informed consent because of the retrospective study design. A total of 165 cases in 159 patients (111 females, 48 males; mean age 41 ± 12 years) who underwent both MRA and hip arthroscopy were evaluated for appearance of the ligamentum teres, including the size, number of bundles, and ligamentum teres tears. Marrow edema of the fovea capitis adjacent to the ligamentum teres insertion and the presence of hip plicae were also recorded.

RESULTS

The mean thickness and length of the ligamentum teres were 3.5 ± 1.5 mm and 25.2 ± 3.8 mm, respectively. Sensitivity, specificity, positive and negative predictive value, and accuracy of MRA for the detection of ligamentum teres tears were 78, 97, 74, 97, and 95%, respectively.

CONCLUSION

MRA is an accurate method to evaluate the normal morphology and to detect tears of the ligamentum teres.