Lesions of the acetabular labrum: accuracy of MR imaging and MR arthrography in detection and staging

MR Imaging Evaluation of Hip Dysplasia in the Young Adult

Hip dysplasia in the young adult population is a significant contributing factor in the development of early osteoarthritis. Diagnosis and treatment planning relies on a comprehensive imaging assessment of the hip joint morphology to better detect and characterize disease. This article discusses the various diagnostic markers of hip dysplasia in the adult population on radiography, computed tomography, and MR imaging.

Update on MR Imaging of the Acetabular Labrum

Acetabular labral tears are a mechanical cause of hip pain. Hip MR imaging should be performed on 3T magnets using small field of view and high-resolution imaging. If using a lower strength magnet, direct arthrography should be performed. The following should be used in the assessment for labral tear abnormalities on MR (or MR arthrography): labral morphology, abnormal T2 signal (or contrast) extension into the labral substance or chondrolabral junction. Description of the labral tear and extent of tear is useful for the hip preservation surgeon. Understanding the pitfalls around the acetabular labral complex will help avoid misinterpretation of labral tears.

Persistence of Labral Tears and Resolution of Paralabral Cysts With 2-Year Magnetic Resonance Imaging Analysis After Periacetabular Osteotomy for Hip Dysplasia

PURPOSE

To evaluate the labrum status and paralabral cysts on preoperative and postoperative magnetic resonance imaging (MRI) in patients with developmental dysplasia of the hip (DDH) who underwent periacetabular osteotomy (PAO).

METHODS

A retrospective review was conducted using prospectively collected data from patients who had undergone primary PAO between June 1, 2021, and May 30, 2022. Inclusion criteria were an age range of 16 to 55 years and a minimum follow-up of 2 years. MRI was used to evaluate the preoperative and postoperative conditions of the labrum and the presence of paralabral cysts. Furthermore, the correlations between the presence of paralabral cysts and demographic and radiographic variables were investigated. Additionally, patient-reported outcomes (PROs), minimal clinically important difference, and complications were reported during the final follow-up evaluation.

RESULTS

A total of 23 patients were included in the final analysis, with an average follow-up of 26.6 ± 3.4 months (range, 24-32 months). All patients diagnosed with symptomatic DDH exhibited labrum tears. MRI scans revealed paralabral cysts in 10 of 24 (41.6%) patients, with a significant correlation noted between the presence of cysts and preoperative lateral center-edge angle (ρ = -0.649; P = .001), anterior center-edge angle (ρ = -0.637; P = .001), Tönnis angle (ρ = 0.593; P = .002) and age (ρ = -0.444; P = .034). Postoperative MRI scans at 1 year showed resolution of all paralabral cysts, while labral tears were found to persist. At the end of the follow-up period, most patients improved considerably in PROs compared with preoperative values. The probabilities of achieving the minimal clinically important difference were 91.3% on the Hip Outcome Score-Activities of Daily Living, 78.2% on the Hip Outcome Score-Sports Subscale, 91.3% on the modified Harris Hip Score, 73.9% on the International Hip Outcome Tool 12-component form, and 69.6% on the visual analog scale pain scale.

CONCLUSIONS

All symptomatic patients with DDH had labral tears and a high prevalence of paralabral cysts, which were corrected with reduced acetabular coverage. After PAO surgery, patients experienced notable enhancements in PROs, with resolution of paralabral cysts but persistence of labral tears.

LEVELS OF EVIDENCE

Level Ⅳ, retrospective case series.

Radial Planes in Hip Magnetic Resonance Imaging: Techniques, Applications, and Perspectives

The hip cartilage and labrum, as the main targets of femoroacetabular impingement, sports-related or traumatic damage, as well as congenital and developmental abnormalities, have attracted increasing attention with the development of magnetic resonance imaging (MRI) and hip arthroscopy. MRI is a commonly used imaging modality to noninvasively visualize the hip cartilage and labral lesions. However, conventional orthogonal MRI planes encounter unique challenges given the ball-and-socket configuration of the hip joint, its anatomically abducted and anteverted orientation, and the thin, closely apposed cartilage enveloping the femoral head and acetabulum. Advancements in hip MRI's radial plane, which is acquired through the center of the hip joint, offer a solution. This technology provides true cross-sectional images of the cartilage and labrum perpendicular to the curvature of the joint, thereby mitigating the partial-volume-averaging effects. The integration of 3.0-Tesla high field strength and three-dimensional (3D) acquisition techniques further enhances the capabilities of the radial plane. This combination yields a high signal-to-noise ratio, high spatial resolution, high contrast between intraarticular structures, while minimizing partial-volume-averaging effects. Such improvements potentially facilitate the comprehensive detection of even minor chondral and labral lesions. The capability for multiplanar reconstruction from a single 3D volumetric acquisition further strengthens the usefulness of the radial plane by aiding in precise localization of hip cartilage and labral lesions, in line with hip arthroscopy findings. These advancements have the potential to standardize MRI evaluations and radiographic reporting systems for hip cartilage and labrum, offering precise guidance for hip arthroscopy. This article presents a comprehensive review of radial plane technology applied to the hip MRI, and discusses the morphological assessment and localization of hip cartilage and labral lesions utilizing this advanced imaging technique. EVIDENCE LEVEL: 5 TECHNICAL EFFICACY: Stage 2.

Magnetic Resonance Imaging and Magnetic Resonance Arthrography Are Both Reliable and Similar When Measuring Hip Capsule Thickness in Patients With Femoroacetabular Impingement Syndrome

Purpose

To propose an accurate method of measuring hip capsular thickness in patients with femoroacetabular impingement syndrome and to compare the reliability of these measurements between magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA).

Methods

A previously established database of patients with femoroacetabular impingement syndrome (FAIS) was used to identify candidates with preoperative MRI or MRA from November 2018 to June 2021. Two reviewers independently examined preoperative imaging for 85 patients. Capsular thickness was measured in 12 standardized locations. Intraclass correlation coefficients (ICCs) were calculated using an absolute-agreement, 2-way random-effects model. Using the same method, 30 patients were randomly selected for repeat measurements by 1 reviewer following a washout period. Ten additional patients with preoperative MRI and MRA of the same hip were identified to compare measurements between modalities using paired samples t test.

Results

ICCs for measurements on MRIs and MRAs using these proposed measurements to compare inter-rater reliability were 0.981 and 0.985. ICCs calculated using measurements by a single reviewer following a washout period for intrarater reliability were 0.998 and 0.991. When comparing MRI and MRA measurements in the same patient, t test for all pooled measurements found no difference between modality (P = .283), and breakdown of measurements by quadrant found no difference in measurements (P > .05), with the exception of the inferior aspect of the capsule on coronal sequences (P = .023).

Conclusions

In patients with FAIS, both MRI and MRA have excellent reliability for quantifying hip capsular thickness. A difference in capsular thickness was found only when comparing MRI and MRA on inferior coronal aspects of the hip capsule, indicating interchangeability of these imaging modalities when measuring the clinically important aspects of the hip capsule.

Level of Evidence

Level IV, diagnostic case series.

Hip Capsulolabral Complex: Anatomy, Disease, MRI Features, and Postoperative Appearance

The hip is a uniquely constrained joint with critical static stability provided by the labrum, capsule and capsular ligaments, and ligamentum teres. The labrum is a fibrocartilaginous structure along the acetabular rim that encircles most of the femoral head. Labral tears are localized based on the clock-face method, which determines the extent of the tear while providing consistent terminology for reporting. Normal labral variants can mimic labral disease and can be differentiated by assessment of thickness or width, shape, borders, location, and associated abnormalities. The Lage and Czerny classification systems are currently the most well-known arthroscopic and imaging systems, respectively. Femoroacetabular impingement is a risk factor for development of labral tears and is classified according to bone dysmorphisms of the femur ("cam") or acetabulum ("pincer") or combinations of both (mixed). The capsule consists of longitudinal fibers reinforced by ligaments (iliofemoral, pubofemoral, ischiofemoral) and circular fibers. Capsular injuries occur secondary to hip dislocation or iatrogenically after capsulotomy. Capsular repair improves hip stability at the expense of capsular overtightening and inadvertent chondral injury. The ligamentum teres is situated between the acetabular notch and the fovea of the femoral head. Initially considered to be inconsequential, recent studies have recognized its role in hip rotational stability. Existing classification systems of ligamentum teres tears account for injury mechanism, arthroscopic findings, and treatment options. Injuries to the labrum, capsule, and ligamentum teres are implicated in symptoms of hip instability. The authors discuss the labrum, capsule, and ligamentum teres, highlighting their anatomy, pathologic conditions, MRI features, and postoperative appearance. ©RSNA, 2024 Test Your Knowledge questions for this article are available in the supplemental material.

Acetabular Labral Repair and Selective Labral Debridement Show No Significant Difference in Clinical Outcomes at a Minimum 2-Year Follow-Up

PURPOSE

To compare the outcomes of arthroscopic labral repair using looped type suture with a matched-pair selective labral debridement with a minimum 2-years follow-up.

METHODS

We identified 378 patients undergoing primary arthroscopic labral repair using loop-suture and selective labral debridement from January 2, 2018, to December 28, 2020. The labral repair group was matched 1:1 to a selective labral debridement control group by age, sex, body mass index, follow-up period, lateral center-edge angle, Tönnis grade, and preoperative joint space. Before surgery, 3-Tesla radial magnetic resonance imaging with a 3-dimensional double-echo steady-state sequence was obtained following failed nonoperative treatment lasting more than 3 months. Follow-up imaging was conducted at a minimum of 2 years. In both groups, the ratio of positive slices in which a disrupted chondrolabral junction was observed between the 2 o'clock and 11 o'clock positions was measured. Patient-reported outcome scores included the Harris Hip Score, visual analog score, Hip Outcome Score Activities of Daily Living Subscale, and Hip Outcome Score of Sport-Specific Subscale.

RESULTS

In total, 76 patients of the repair group were matched to 76 controls with a minimum 2-years follow-up (repair vs control: 2.6 ± 0.4 vs 2.6 ± 0.4 years, P = .775). The repair group experienced a 2-fold improvement (0.6 ± 0.1 to 0.3 ± 0.1, P＜.001). Although the selective debridement group experienced a 3-fold improvement (0.3 ± 0.1 to 0.1 ± 0.1, P＜.001). Significant improvement of the patient-reported outcome was shown in both groups at final follow-up without significant difference between the 2 groups.

CONCLUSIONS

The mid-term clinical outcomes are comparable between the labral repair using looped type suture and selective labral debridement group. Although a gap between the labrum and articular cartilage may appear in 3-dimensional double-echo steady-state magnetic resonance imaging results after labral repair, it does not correspond with clinical outcomes.

LEVEL OF EVIDENCE

Level III, retrospective comparative study.

Trends in MR Arthrogram Utilization at a Tertiary Care Academic Center

The purpose is to evaluate the trends in MR arthrogram utilization at a tertiary care academic institution and to determine if there are factors that can be implicated in the utilization trends. Number of MR arthrograms of the shoulder, hip, and elbow from 2013-2020 at our institution were identified (n = 1882). Patient demographics including age, sex, sports participation, history of prior surgery, and physician referral were obtained. Descriptive statistics were performed to determine the prevalence of MR arthrograms. Linear regression analyses were performed to determine the relationship of time with prevalence of arthrograms. Chi-square tests and posthoc analyses with Bonferroni correction were used to assess if categorical variables were different between the years. There was overall decrease in the prevalence of MR arthrograms of the shoulder, hip, and elbow despite an increase in the overall MR volume during the study period. Linear regression models significantly predicated decrease in arthrogram prevalence with each passing year (P < 0.001). The percentage of orthopedic referrals for arthrograms in the hip (P = 0.002) and shoulder (P = < 0.001) decreased significantly towards the end of the study period. None of the other variables assessed were significant. At our tertiary care academic institution, arthrogram utilization has been drastically decreasing over the past 8 years. The percentage of orthopedic referrals for shoulder and hip arthrograms significantly decreased at the end of the study period.

Imaging of Anatomical Variants Around the Hip

Considering the current widespread use of imaging as an integral part of managing hip pain, variable hip geometries and anatomical variants are increasingly being detected. These variants are commonly found in the acetabulum and proximal femur, as well as the surrounding capsule-labral tissues. The morphology of specific anatomical spaces confined by the proximal femur and the bony pelvis may also vary significantly among individuals. Familiarity with the spectrum of imaging appearances of the hip is necessary to identify variant hip morphologies with or without potential clinical relevance and reduce an unnecessary work-up and overdiagnosis. We describe anatomical variations and variable morphologies of the bony structures comprising the hip joint and the soft tissues, around the hip. The potential clinical significance of these findings is further analyzed in conjunction with the patient's profile.

[Preoperative MR imaging for hip dysplasia : Assessment of associated deformities and intraarticular pathologies]

BACKGROUND

Developmental dysplasia of the hip (DDH) is a known reason for hip pain for adolescents and young adults. Preoperative imaging is increasingly recognized as an important factor due to the recent advances in MR imaging.

OBJECTIVES

The aim of this article is to give an overview of preoperative imaging for DDH. The acetabular version and morphology, associated femoral deformities (cam deformity, valgus and femoral antetorsion) and intraarticular pathologies (labrum and cartilage damage) and cartilage mapping are described.

METHODS

After an initial evaluation with AP radiographs, CT or MRI represent the methods of choice for the preoperative evaluation of the acetabular morphology and cam deformity, and for the measurement of femoral torsion. Different measurement techniques and normal values should be considered, especially for patients with increased femoral antetorsion because this could lead to misinterpretation and misdiagnosis. MRI allows analysis of labrum hypertrophy and subtle signs for hip instability. 3D MRI for cartilage mapping allows quantification of biochemical cartilage degeneration and yields great potential for surgical decision-making. 3D-CT and, increasingly, 3D MRI of the hip to generate 3D pelvic bone models and subsequent 3D impingement simulation can help to detect posterior extraarticular ischiofemoral impingement.

RESULTS AND DISCUSSION

Acetabular morphology can be divided in anterior, lateral and posterior hip dysplasia. Combined osseous deformities are common, such as hip dysplasia combined with cam deformity (86%). Valgus deformities were reported in 44%. Combined hip dysplasia and increased femoral antetorsion can occur in 52%. Posterior extraarticular ischiofemoral impingement between the lesser trochanter and the ischial tuberosity can occur in patients with increased femoral antetorsion. Typically, labrum damage and hypertrophy, cartilage damage, subchondral cysts can occur in hip dysplasia. Hypertrophy of the muscle iliocapsularis is a sign for hip instability. Acetabular morphology and femoral deformities (cam deformity and femoral anteversion) should be evaluated before surgical therapy for patients with hip dysplasia, considering the different measurement techniques and normal values of femoral antetorsion.

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.

Two Novel Clinical Tests for the Diagnosis of Hip Labral Tears

BACKGROUND

There are few well-studied clinical tests for the diagnosis of hip labral tears. As the differential diagnosis for hip pain is broad, accurate clinical examination is important in guiding advanced imaging and identifying patients who may benefit from surgical management.

PURPOSE

To determine the diagnostic accuracy of 2 novel clinical tests for the diagnosis of hip labral tears.

STUDY DESIGN

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

METHODS

Clinical examination findings including the Arlington, twist, and flexion-adduction-internal rotation (FADIR)/impingement tests as performed by a fellowship-trained orthopaedic surgeon specializing in hip arthroscopy were obtained from retrospective chart review. The Arlington test ranges the hip from flexion-abduction-external rotation to FADIR while applying subtle internal rotation and external rotation motion. The twist test involves internal rotation and external rotation of the hip while weightbearing. Diagnostic accuracy statistics for each of the tests were calculated using magnetic resonance arthrography as the reference standard.

RESULTS

A total of 283 patients were included in the study with a mean age of 40.7 years (range, 13-77 years) and 66.4% were women. The Arlington test was found to have a sensitivity of 0.94 (95% CI, 0.90-0.96), specificity of 0.33 (95% CI, 0.16-0.56), positive predictive value (PPV) of 0.95 (95% CI, 0.92-0.97), and negative predictive value (NPV) of 0.26 (95% CI, 0.13-0.46). The twist test was found to have a sensitivity of 0.68 (95% CI, 0.62-0.73), specificity of 0.72 (95% CI, 0.49-0.88), PPV of 0.97 (95% CI, 0.94-0.99), and NPV of 0.13 (95% CI, 0.08-0.21). The FADIR/impingement test was found to have a sensitivity of 0.43 (95% CI, 0.37-0.49), specificity of 0.56 (95% CI, 0.34-0.75), PPV of 0.93 (95% CI, 0.87-0.97), and NPV of 0.06 (95% CI, 0.03-0.11). The Arlington test was significantly more sensitive than both the twist and FADIR/impingement tests (P < .05), while the twist test was significantly more specific than the Arlington test (P < .05).

CONCLUSION

The Arlington test is more sensitive than the traditional FADIR/impingement test, while the twist test is more specific than the FADIR/impingement test in diagnosing hip labral tears in the hands of an experienced orthopaedic surgeon.

"Anterior-shift sign": a novel MRI finding of adult hip dysplasia

INTRODUCTION

In adult hip dysplasia, methods for direct evaluation of hip instability have not been established. The present study aimed to determine findings suggestive of hip instability on magnetic resonance imaging (MRI) and to evaluate their correlations with clinical and radiological factors.

MATERIALS AND METHODS

We retrospectively reviewed 72 hips in 50 patients with hip dysplasia (45 females, 5 males; mean age: 40.0 years; age range: 15-59 years; Kellgren-Lawrence grade: ≤ 2). Hip dysplasia was defined as a lateral center-edge angle < 25°. Among the hips, 50 had pain (symptomatic dysplasia group) and 22 were asymptomatic (asymptomatic dysplasia group). As controls, 12 normal hips in 12 patients who underwent screening for asymptomatic osteonecrosis of the femoral head by MRI were evaluated. Using an oblique axial view on fat-suppressed T2-weighted images, we evaluated the presence of a gap between the posterior part of the femoral head and the corresponding acetabular surface, indicating hip instability (anterior-shift sign). The correlations of anterior-shift sign with clinical and radiographical factors were examined.

RESULTS

Anterior-shift sign was observed in 92.0% in the symptomatic dysplasia group, 9.1% in the asymptomatic dysplasia group, and 0% in the control group. In adult hip dysplasia, cases with anterior-shift sign had significantly more pain and labrum tear occurrence than cases without anterior-shift sign. Anterior-shift sign was correlated with Kellgren-Lawrence grade and degree of acetabular coverage.

CONCLUSIONS

This study suggested that hip instability can be observed as the anterior-shift sign on MRI. This sign is useful when considering indications for periacetabular osteotomy in adult hip dysplasia.

Can Non-Contrast 3T MRI scans predict the type of labral procedure in hip arthroscopy?

PURPOSE

The study proposed a simple classification system that aimed at predicting the labral procedure during hip arthroscopy using images from unenhanced 3T MRI scans.

PATENTS AND METHODS

Forty patients undergoing hip arthroscopy had their MRI scans reviewed pre-operatively by one of two senior radiologists and classified into: type 1: stable labrum with intra-substance degeneration (no labral repair required), type 2: unstable labrum, no intra-substance degeneration (labral repair required), or type 3: unstable labrum with intra-substance degeneration (Labral repair not feasible). Hip arthroscopy is carried out by one of two surgeons and classified accordingly while blinded to the radiologists' assessment.

RESULTS

The pre-operative radiological classification managed to predict the labral procedure in 29 cases out of 40 (72.5%). The gamma value was 0.83, and the kappa value was 0.46 denoting moderate agreement. The inter-class correlation coefficient was 0.52 indicating moderate reliability.

CONCLUSION

The proposed classification showed a moderate agreement between the radiological findings and arthroscopic findings. As we cannot accurately correlate the MRI findings with the type of surgical management, the surgeon should be prepared for all scenarios of labral procedures.

LEVEL OF EVIDENCE

Level IV (case series).

Hip Arthroscopy for Femoroacetabular Impingement-Associated Labral Tears: Current Status and Future Prospects

Femoroacetabular impingement (FAI) has emerged as a common cause of hip pain, especially in young patients. While the exact cause of FAI is unknown, it is thought to result from repetitive microtrauma to the proximal femoral epiphysis leading to abnormal biomechanics. Patients typically present with groin pain that is exacerbated by hip flexion and internal rotation. Diagnosis of FAI is made through careful consideration of patient presentation as well as physical exam and diagnostic imaging. Use of radiographs can help diagnose both cam and pincer lesions, while the use of MRI can diagnose labral tears and cartilage damage associated with FAI. Both non-operative and surgical options have their role in the treatment of FAI and its associated labral tears; however, hip arthroscopy has had successful outcomes when compared with physical therapy alone. Unfortunately, chondral lesions associated with FAI have had poorer outcomes with a higher conversion rate to arthroplasty. Capsular closure following hip arthroscopy has shown superior clinical outcomes and therefore should be performed if possible. More recently, primary labral reconstruction has emerged in the literature as a good option for irreparable labral tears. While non-operative management may have its role in treating patients with FAI, hip arthroscopy has developed a successful track record in being able to treat cam and pincer lesions, chondral damage, and labral injuries.

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.

Arthroscopic acetabular labrum suture

It is essential to be aware of the anatomy and biomechanics of the acetabular labrum in order to understand why it should be conserved. Vascularization comes from the capsule and also from the bone. The joint side contains numerous nerve endings, which explains why labral lesions are painful. It is involved in joint stabilization by maintaining a negative pressure inside the joint able to resist distraction. It acts as a seal. There are two main suture techniques: trans- and peri-labral. Translabral suture is better suited to a wide and solid labrum free of degenerative lesions. Both techniques should be known, and may be associated. Results are comparable. It is essential to manage the underlying pathology responsible for the labral lesion. Joint degeneration is associated with poor prognosis. It needs to be recognized and discussed with the patient, to avoid unrealistic expectations.

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.

Impact of bone deformities and labral and cartilage lesions on early functional results of arthroscopic treatment of femoroacetabular impingement

INTRODUCTION

Femoroacetabular impingement (FAI) is a frequent cause of inguinal pain. Treatment failure rates range between 2.9% and 13.2%. The aim of the present study was to assess the impact of preoperative bone deformities (BD), labral lesions (LL) and cartilage lesions (CL) on clinical results of arthroscopic treatment of FAI.

MATERIAL AND METHOD

A prospective operational study included patients undergoing hip arthroscopy for FAI. All patients had full radiographic work-up and clinical assessment on Non-Arthritic Hip Score (NAHS), preoperatively and at 1year. Hips with Tönnis grade>1, coxa profunda [VCE (vertical center edge angle)>35°] or borderline dysplasia (VCE<25°) were excluded. The Czerny classification was used for the labrum and the Beck classification for the cartilage. The aim of the study was to assess the impact of preoperative BD, LL and CL on clinical results of arthroscopic treatment of FAI. The study hypothesis was that type of lesion does not influence early functional results at 1year, whatever the technique used for the labrum.

RESULTS

One hundred and ninety-seven patients were included. Mean preoperative NAHS was 59.1±17.5. There were 145 patients with labral suture (73.6%), 42 with labral debridement (21.3%) and 10 with conservative treatment (5.1%). At 1year, mean NAHS was 88.1±15.3: i.e., a significant improvement (p<2.2×10^-16). Improvement was also significant in the debridement, non-operative and suture subgroups. BD showed significant correction in the overall population (alpha angle 48.2° postoperatively versus 66.7° preoperatively; crossing sign in 14.5% versus 62.9% of cases). There were no significant differences in functional scores according to extension or type of labral or cartilage lesion. At follow-up, 3 patients (1.5%) required repeat arthroscopy.

CONCLUSION

The present study showed that early functional results of arthroscopic treatment of FAI were unaffected by the severity of bone deformity (alpha and VCE angles), or extension or type of labral or cartilage lesion. Regardless of BD, LL and CL, 1-year clinical progression was satisfactory when all bone deformities were treated by the arthroscopic procedure.

LEVEL OF EVIDENCE

IV; prospective non-comparative study.

Imaging update on cartilage

In this update article, we present a review of the literature regarding the physiology of the articular cartilage, role of MR imaging in cartilage assessment, MRI sequences and protocols for cartilage imaging, brief overview of classifications and nomenclature for chondral and osteochondral lesions, MR imaging following cartilage repair and degenerative osteoarthritis.

Microfracture of Acetabular Rim After Segmental Labral Resection to Restore the Morphology and Function of Labrum: A Retrospective Study of More than 2 Years Follow-up

Objective

To report on the clinical outcome of patients undergoing combined arthroscopic treatment of labral resection and microfracture at the rim of acetabulum at a minimum 2‐year follow‐up.

Methods

The retrospective study included 38 patients undergoing hip arthroscopy for irreparable labral injury from 24 February 2014 to 26 February 2018. Thirteen patients were excluded owing to patient refusal of participation and concomitant diseases like synovial chondromatosis and dysplasia hip. The study group consisted of patients undergoing combined arthroscopic labral resection and microfracture at the rim of acetabulum (MICRO Group: 20 patients), arthroscopic labral resection alone (RESEC Group: five patients). Postoperative three‐dimensional (3D) double‐echo steady‐state (DESS) sequence with radial imaging at 3 Tesla were obtained and fluoroscopic image of the involved hip under distraction were used to observe the restoration of vacuum effect. Patient‐reported outcome scores (PROs) including the Harris Hip Score (HHS), Visual Analogue Score (VAS), Hip Outcome Score Activities of Daily Living Subscale (HOS‐ADL), Hip Outcome Score Sport‐Specific Subscale (HOS‐SSS) were collected and compared between two groups.

Results

All patients were followed up for at least 6 months. The follow‐up time of RESEC group is longer than MICRO group (46.6 months vs 23.9 months, P < 0.05). The 3D DESS imaging demonstrated intermediate signal intensity at the relative area where the labrum resected followed by microfracture at the acetabular rim in MICRO group. Meanwhile, regrowth of labrum‐like tissue was not observed in MRI imaging of the RESEC group. Furthermore, vacuum effect was more apparent in MICRO group compared with RESEC group. All PROs in both groups showed a statistically significant improvement at follow‐up compared with preoperative levels. RESEC group: HHS (73.0 vs 93.8, P < 0.05); HOS‐ADL (51.5 vs 89.1, P < 0.05); HOS‐SSS (47.8 vs 88.3, P < 0.05); VAS (6.4 vs 2.0, P < 0.05). MICRO group: HHS (70.5 vs 91.5, P < 0.05); HOS‐ADL (52.4 vs 87.0, P < 0.05); HOS‐SSS (48.1 vs 86.5, P < 0.05); VAS (6.3 vs 1.6, P < 0.05). One patient of MICRO group had transient neurapraxias of the pudendal nerve that resolved completely by 3 months. There showed no statistically significant difference between groups regarding the preoperative and postoperative PROs.

Conclusion

Compared to labral resection, combined arthroscopic labral resection and microfracture at the rim of acetabulum is able to fulfill the labral defect area with the potential to restore the seal effect of labrum as an effective and safe option for irreparable segmental labral tears.

Hip Pain: Imaging of Intra-articular and Extra-articular Causes

Hip pain is a common and complex clinical entity. The causes of hip injuries in athletes are many and diverse, requiring efficient, accurate diagnosis for proper management. Imaging is an important step in the clinical evaluation of hip pain, and familiarity with multiple imaging modalities as well as characteristic imaging findings is a helpful tool for sports medicine clinicians. This article discusses imaging recommendations and gives imaging examples of common causes of intra-articular and extra-articular hip pain including femoroacetabular impingement, labral tears, cartilage defects, ligamentum teres injuries, snapping hip syndrome, femoral stress injuries, thigh splints, athletic pubalgia, avulsion injuries, and hip dislocation.

[Direct MR Arthrography of the Hip: Diagnosis and Pitfalls of Acetabular Labral Lesions]

Tearing of the acetabular labrum is a common cause of chronic hip pain. MR arthrography (MRA) of the hip is the imaging procedure of choice for the evaluation of acetabular labrum. Familiarity with the various imaging findings of MRA of the hip allows recognition of normal variants and differentiation from true pathologic conditions. This article comprehensively reviews the technical aspects and interpretation of MRA of the hip. The appearances of normal and abnormal labra in MRA are discussed. Potential pitfalls in labral tear interpretation, such as sulci around the hip, normal variants of the labrum and plicae, and osseocartilaginous and soft tissue lesions identified on MRA of the hip are also described.

Femoroacetabular Impingement and Labral Tear: From the Most Highly Cited Articles to Research Interests

Objective

To highlight the characteristics of the most highly cited articles and propose the research interests over the past decades in the field of femoroacetabular impingement (FAI) and labral tear.

Methods

The ISI Web of Science database (Clarivate Analytics, New York, the United States) was utilized for the identification of articles on 15 December 2020. FAI and labral tear‐related articles (1138 articles) were retrieved, of which the 100 most‐cited articles (top 100) were identified. Subsequent analysis included citation density (citations/article age), authorship, institution, journal, geographic distribution, level of evidence, and theme.

Results

The number of citations per article ranged from 66 to 1189 with a mean of 163.31. The majority of articles were published in the United States (all articles/top 100 = 655/57) and Switzerland (85/22). University of Bern (n = 10) was the most prolific institution. The journal with the most of articles was Arthroscopy: The Journal of Arthroscopic and Related Surgery. The most prolific coauthor (all articles) or first authors (top 100) was Domb (n = 109) and Philippon (n = 6), respectively. The evidence with the most articles is level IV (n = 41). The top three most popular topics of research article were outcomes of surgery (n = 23), imaging diagnosis (n = 18), and comparison of surgery (n = 8). The top four most prevalent themes of review were labral tears (n = 3), FAI (n = 3), comparison of surgery imaging diagnosis, and outcomes of surgery (both n = 2). Six keywords with the newest average publication year, including FAI syndrome (average publication year = 2019.50), patient‐reported outcomes (2019.43), femoroplasty (2018.60), clinical outcomes (2018.17), borderline dysplasia (2018.00), and capsule (2018.00). Five keywords with the highest average citations, including outcome (average citations = 88.50), alpha angle (58.00), complications (55.86), revision hip arthroscopy (49.00), and systematic review (46.14).

Conclusions

Outcomes research is the most popular research interest and patient‐reported outcome instruments might be further and widely used in the emerging articles in the near future. The field of FAI and labral tear has shown an obvious trend of development and is steadily evolving. It could be predicted that there will be an increasing number of publications in the following years, with the United States and Switzerland maintaining leadership in this field.

The imaging evaluation of acetabular labral lesions

The acetabular labrum is an important structure that contributes to hip joint stability and function. Diagnosing labral tears involves a comprehensive assessment of clinical symptoms, physical examinations, imaging examinations, and arthroscopic confirmation. As arthroscopy is an invasive surgery, adjuvant imaging of the acetabular labrum is increasingly imperative for orthopedists to diagnose and assess labral lesions prior to hip arthroscopy for surgical management. This article reviews the current imaging strategies for the evaluation of labrum lesions.

Determining Reliability of Arthroscopic Classifications for Hip Labral Tears

OBJECTIVE

Evaluate interobserver and intraobserver reliability of hip arthroscopic classifications for labral tears.

DESIGN

Retrospective diagnostic study of nonconsecutive patients.

SETTING

Institutional study.

PATIENTS

From a database of 278 hip arthroscopy videos for treatment of femoroacetabular impingement, 70 videos were chosen by simple random sampling. Exclusion criteria included presence of radiological arthrosis (Tonnis > 2), previous hip surgery, inadequate lesion palpation, poor image quality, and refusal to participate in the study. The final sample included 60 videos.

INTERVENTIONS

Four hip surgeons evaluated the videos twice at 1-month intervals and classified the lesions according to Lage, Seldes, and Beck classifications for hip labral tears.

MAIN OUTCOME MEASURES

Interobserver and intraobserver reliability with the percent of agreement and weighted Cohen kappa values.

RESULTS

Patients had a mean age of 33 years (SD, 7; range, 18-47 years), and 32 (53%) were men. Femoroacetabular impingement types included combined (CAM and pincer) in 31 (52%), CAM in 27 (45%), and pincer in 2 (3%). For interobserver reliability, the average weighted kappa values were 0.68, 0.65, and 0.78 for the Lage, Seldes, and Beck classifications, respectively. For intraobserver reliability, the mean weighted kappa values were 0.87, 0.64, and 0.93 for the Lage, Seldes, and Beck classifications, respectively.

CONCLUSIONS

Beck classification had the highest average values for interobserver and intraobserver agreements. Lage, Seldes, and Beck scores for acetabular labrum tears showed substantial interobserver agreement. In the intraobserver evaluation, the Seldes system presented substantial agreement, whereas Lage and Beck classifications were considered excellent agreement.

The Lisbon Agreement on Femoroacetabular Impingement Imaging-part 3: imaging techniques

OBJECTIVES

Imaging diagnosis of femoroacetabular impingement (FAI) remains controversial due to a lack of high-level evidence, leading to significant variability in patient management. Optimizing protocols and technical details is essential in FAI imaging, although challenging in clinical practice. The purpose of this agreement is to establish expert-based statements on FAI imaging, using formal consensus techniques driven by relevant literature review. Recommendations on the selection and use of imaging techniques for FAI assessment, as well as guidance on relevant radiographic and MRI classifications, are provided.

METHODS

The Delphi method was used to assess agreement and derive consensus among 30 panel members (musculoskeletal radiologists and orthopedic surgeons). Forty-four questions were agreed on and classified into five major topics and recent relevant literature was circulated, in order to produce answering statements. The level of evidence was assessed for all statements and panel members scored their level of agreement with each statement during 4 Delphi rounds. Either "group consensus," "group agreement," or "no agreement" was achieved.

RESULTS

Forty-seven statements were generated and group consensus was reached for 45. Twenty-two statements pertaining to "Imaging techniques" were generated. Eight statements on "Radiographic assessment" and 12 statements on "MRI evaluation" gained consensus. No agreement was reached for the 2 "Ultrasound" related statements.

CONCLUSION

The first international consensus on FAI imaging was developed. Researchers and clinicians working with FAI and hip-related pain may use these recommendations to guide, develop, and implement comprehensive, evidence-based imaging protocols and classifications.

KEY POINTS

• Radiographic evaluation is recommended for the initial assessment of FAI, while MRI with a dedicated protocol is the gold standard imaging technique for the comprehensive evaluation of this condition. • The MRI protocol for FAI evaluation should include unilateral small FOV with radial imaging, femoral torsion assessment, and a fluid sensitive sequence covering the whole pelvis. • The definite role of other imaging methods in FAI, such as ultrasound or CT, is still not well defined.

Using a simplified version of a common surgical grading scale for acetabular labral tears improves the utility of preoperative hip MRI for femoroacetabular impingement

OBJECTIVE

To evaluate whether a commonly used surgical grading scale, when applied to acetabular labral findings on MRI, could improve preoperative planning and counseling for patients undergoing hip arthroscopy.

MATERIALS AND METHODS

We evaluated 76 clinical MRIs performed on patients with femoroacetabular impingement. Three musculoskeletal radiologists and one musculoskeletal fellow reviewed each scan in a blinded fashion, classifying the acetabular labrum from 12:00 to 4:00 using the Beck scale, a common surgical grading scale. Clinical correlation was provided via surgical examination and classification. Reliability was determined between readers and between reader and surgical data using Cohen's kappa and Krippendorff's alpha at each clock position and for the worst grading for each scan. In addition, a simplified version of the scale comprised of only two grades, potentially reparable and not potentially reparable, was evaluated.

RESULTS

When the scale was simplified into categories of potentially reparable and not potentially reparable, the sensitivity was excellent, ranging from 85.5 to 96%. Observer agreement when using individual Beck grades was found to range from poor to fair; Kappa ranged from 0.03 to 0.19, and Alpha ranged from - 0.27 to 0.22.

CONCLUSION

The simplified version of the Beck labral scale when applied to MRI is a highly sensitive predictor of potentially reparable labral pathology while excluding normal and grossly degenerative tissue. Use of this scale provides clinically relevant information that can drive preoperative planning and improve patient counseling. It does so in a standardized fashion that can be applied across practice sites and without additional cost.

The efficacy of intra-articular HYADD4-G injection in the treatment of femoroacetabular impingement: results at one year follow up

Objective

Femoroacetabular impingement (FAI) is a condition that has been increasingly recognized as a source of hip pain and a possible risk factor to early development of hip osteoarthritis (OA). To our knowledge, the use of HA in the treatment of femoroacetabular FAI has been investigated only by two studies, both using a high molecular weight HA. The aim of this study was to evaluate the efficacy of two weekly injections of an hexadecylamide derivative of HA (HYADD4-G, HYMOVIS, Fidia Farmaceutici) in FAI.

Methods

All patients received two weekly intra-articular injections of Hymovis at baseline and after 7 days. Clinical and functional assessments were performed at baseline and was repeated after 1, 3, 6 and 12 months. Functional measures included visual analogue scale (VAS) for pain, Harris Hip score (HHS), Lequesne Index (LI), Tegner activity level scale (TALS) and monthly consumption of nonsteroidal anti-inflammatory drugs (NSAIDs).

Results

Twenty-one hips (19 patients, 2 bilateral cases) were treated. The variables VAS, HHS as well as Lequesne improved significantly from T0 to T4 (at 12 months) with the best improvement between T0 and T1. At the same time, a reduction in NSAIDs monthly intake was registered. On the other hand, a significant improvement in Tegner scale was not observed. No adverse events were registered.

Conclusion

This study states that one cycle of HYADD4-G could be a safe and effective treatment in patients with FAI, showing significative results in term of pain control as well as hip functionality and quality of life up to 1 year.

A novel arthroscopic classification of labral tear in hip dysplasia

Background

Acetabular labral tears cause of pain in patients with symptomatic hip dysplasia. To date, no structured grading system has been developed to evaluate labral tears in these patients. The present study describes a new system of grading labral tears in patients with acetabular dysplasia.

Methods

The data of 66 patients who underwent hip arthroscopy for symptomatic hip dysplasia from March 2014 to February 2018 were reviewed. Labral tears were classified into four groups, based on the occurrence of chondrolabral junction (CLJ) disruption, capsulolabral recess (CLR) disruption, and labral displacement. Labral tears without instability were classified as grade 1 or 2. Partial delamination or blistering of the labrum with minimal fraying at the CLJ was classified as grade 1, whereas labral tears with CLJ disruption were classified as grade 2. Unstable labral tears with CLR disruption followed by CLJ disruption, but without labral displacement, were classified as grade 3, whereas unstable labral tears with CLR and CLJ disruption, but with labral displacement, were classified as grade 4. The radiological and clinical characteristics of patients in each grade were determined including by simple radiographs and MRI/MR arthrography, as were concomitant findings, including rupture of the ligamentum teres, articular cartilage damage, and presence of a paralabral cyst. The surgical options selected for each grade and clinical outcomes, including modified Harris hip scores (mHHS) and Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) scores, were evaluated. Spearman’s correlation analyses were performed to assess whether labral tear grade correlated with baseline characteristics, the incidence of concomitant injuries, and the severity of osteoarthritis (OA). The Wilcoxon test for paired data was performed to compare treatment results with pain scores.

Results

The study cohort included six men and 53 women of mean ± SD age 39.9 ± 13.0 years (range, 15–66 years). Of the 66 hips, seven (10.6%), 10 (15.2%), 30 (45.5%), and 19 (28.8%) were classified as grades 1–4, respectively. Symptom duration (P = 0.017), preoperative Tönnis OA grade (P < 0.001), cartilage damage (P < 0.001), and the presence of a paralabral cyst (P = 0.001) correlated significantly with baseline tear grade. In all groups, mHHS and WOMAC scores improved after surgical treatment.

Conclusions

Arthroscopic findings of labral tears in patients with hip dysplasia differed from the conventional classification. The classification system proposed in this study will likely be useful for determining the degree of labral tear in patients with hip dysplasia and for predicting treatment outcomes.

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.

Diagnosing acetabular labral tears with hip traction sonography: a case series

PURPOSE

Three cases of acetabular labral tear (ALT) diagnosed with sonography (US) are reported. We aim to show utility for US with the addition of manual hip traction as an adjunctive modality to the current diagnostic imaging of choice, magnetic resonance arthrography (MRA), for diagnosing ALT.

METHODS

Three cases of young athletic patients with similar clinical presentations are reported. All received US examination of the hip with attention to the labrum that included a novel long-axis hip traction technique which assisted in diagnosing ALT.

RESULTS

In the first and second cases, MRA and orthopedic consult were obtained for confirmation of the diagnosis. Arthroscopy was performed to correct the ALT. The third patient declined an MRA. Conservative management consisted of McKenzie method active care, resulting in return to sport in the third case.

CONCLUSION

These three cases demonstrate the clinical and sonographic presentation of ALT. The dynamic long-axis hip traction protocol facilitated the use of US as an adjunctive modality for diagnosing ALT by increasing the visualization of the defect.

Comparison Between 3-Dimensional Multiple-Echo Recombined Gradient Echo Magnetic Resonance Imaging and Arthroscopic Findings for the Evaluation of Acetabular Labrum Tear

PURPOSE

To evaluate radially reconstructed 3.0-Tesla 3-dimensional multiple-echo recombined gradient echo (MERGE) magnetic resonance imaging (MRI) without arthrography for the assessment of acetabular labrum tears, using arthroscopic evaluation as the reference standard.

METHODS

A total of 71 consecutive hips, including 29 with femoroacetabular impingement, 26 with borderline developmental dysplasia of the hip, and 16 with early-stage osteoarthritis, were evaluated in this retrospective study. MERGE MRI findings were evaluated according to the modified Czerny classification for 3 regions of interest: anterior region, anterolateral region, and lateral region. Cases with severe degeneration that was not concordant with any stage in the original Czerny classification were defined as stage Ⅳ. MERGE MRI findings were compared with arthroscopic findings, and the sensitivity, specificity, positive predictive value, and negative predictive value in terms of the existence of labrum tears were calculated.

RESULTS

MERGE MRI findings revealed labrum tears more frequently in the anterolateral region than in the anterior and lateral regions (P < .01). In cases of femoroacetabular impingement and borderline developmental dysplasia of the hip in particular, labrum tears were more frequently observed on MRI in the anterolateral region than in the lateral region (P < .05). In comparison with MRI findings and arthroscopic findings, our newly defined stage IV in the modified Czerny classification was more frequently observed in cases with a Multicenter Arthroscopy of the Hip Outcomes Research Network (MAHORN) classification of degenerative or complex (P < .01). The average sensitivity and specificity of all regions for the existence of labrum tears were 85% and 56%, respectively. Sensitivity and specificity were 79% and 50%, respectively, in the anterior region; 96% and 50%, respectively, in the anterolateral region; and 70% and 57%, respectively, in the lateral region.

CONCLUSIONS

We validated the diagnostic performance of 3.0-Tesla 3-dimensional MERGE MRI for evaluating acetabular labrum tears and made comparisons with arthroscopic findings. Radially reconstructed MERGE magnetic resonance images showed excellent sensitivity for the diagnosis of labrum tears, particularly in the anterolateral region. The newly defined stage IV was distinctive of early-stage osteoarthritis cases with degeneration and/or complex arthroscopic findings. The noninvasive imaging modality of radially reconstructed MERGE MRI may be an alternative to magnetic resonance arthrography for evaluating labrum tears.

LEVELS OF EVIDENCE

Level Ⅱ, development of diagnostic criteria.

Clinical and Radiographic Predictors for Unsalvageable Labral Tear at the Time of Initial Hip Arthroscopic Management for Femoroacetabular Impingement

BACKGROUND

The acetabular labrum plays important roles in proprioception, nociception, synovial fluid seal effect, and static and dynamic joint stability and as a shock absorber. Clinical and radiographic risk factors for unsalvageable labral tear in femoroacetabular impingement (FAI) are not well established.

PURPOSE

To identify predictors of unsalvageable labral tear during initial hip arthroscopic management of FAI.

STUDY DESIGN

Case-control study; Level of evidence, 3.

METHODS

Patients were included who underwent primary hip arthroscopic treatment for FAI between March 2009 and March 2014. Patients were excluded who had <2-year follow-up, underwent bilateral surgery, or had a history of surgery, osteoarthritis (Tönnis grade 2 or 3), and other diagnoses, including lateral center-edge angle <25° diagnosed as developmental hip dysplasia. Patients were divided into 2 groups according to their labral condition: reconstruction and refixation. Unsalvageable labral tear was defined as any irreparable labral tear, including severe degenerative tear, frayed labrum, labral ossification, flattened labrum, and failed prior repair during surgery. Univariate and multivariate analyses identified risk factors for segmental labral reconstruction. Patient-reported outcome scores and postoperative revision rates were also assessed.

RESULTS

Twenty-five hips (18 male, 7 female) and 126 hips (65 male, 61 female) were included in the reconstruction and refixation groups, respectively. The mean ± SD ages were 52.6 ± 15.0 and 36.5 ± 16.1 years in the reconstruction and refixation groups, respectively. In the reconstruction group, the mean modified Harris Hip Score significantly improved from 67.3 ± 14.9 preoperatively to 95.0 ± 8.1 at final follow-up (P < .001), and the mean Nonarthritic Hip Score improved from 63.0 ± 18.3 preoperatively to 89.5 ± 10.1 at final follow-up (P < .001). In the refixation group, the mean modified Harris Hip Score significantly improved from 69.2 ± 18.6 preoperatively to 93.0 ± 11.2 at final follow-up (P < .001), and the mean Nonarthritic Hip Score improved from 60.7 ± 18.8 preoperatively to 88.6 ± 15.0 at final follow-up (P < .001). No significant difference was noted in patient-reported outcome scores and revision hip arthroscopy rates. The rate of conversion of total hip arthroplasty was higher in the reconstruction group than in the refixation group. Risk factors for unsalvageable labral tear were age ≥45 years (odds ratio [OR], 8.83; P < .007), body mass index ≥23.1 kg/m² (OR, 13.05; P < .001), and vertical center anterior angle ≥36° (OR, 19.03; P < .001). Furthermore, in this study, unsalvageable labral tears were present in cases with at least 2 of the 3 risk factors.

CONCLUSION

Age ≥45 years, body mass index ≥23.1 kg/m², and vertical center anterior angle ≥36° are risk factors for unsalvageable labral tear at initial hip arthroscopic surgery for patients with FAI.

Iliopsoas snapping hip: improving the diagnostic value of magnetic resonance imaging with a novel parameter

OBJECTIVE

To illustrate an advanced imaging parameter that describes the course of the iliopsoas tendon, and evaluate its correlations with iliopsoas internal hip snapping syndrome.

METHODS

This retrospective cohort study reviewed hip MRI images of all patients seen by a single surgeon between January 2015 and March 2016. The comparison group included all patients with clinical internal hip snapping, versus the control group that did not. MRI images were processed using minimum intensity projection. Measurements obtained of the pelvis and course of the iliopsoas tendon included: pelvic incidence, coronal angle, and sagittal opening angle (SOA). Comparison of measurements between the groups was performed with Mann-Whitney U analysis and receiver operator curve (ROC) plotting, with a significance cutoff of p = 0.05.

RESULTS

The control group (n = 85) and comparison group (n = 48) demonstrated no difference in age or gender. Pelvic incidence was similar [51.3 (± 10.7) degrees control versus 52.2 (± 7.7) degrees comparison (p = 0.36)], as was coronal angle [13.9 (± 4.6) degrees control versus 14.8 (±4.8) degrees comparison (p = 0.15)]. There was a significant difference in SOA [137.0 (± 5.9) degrees control versus 141.9 (± 6.5) degrees comparison (p < 0.01)]. ROC analysis revealed SOA threshold of 140 degrees for clinical IP hip snapping (p < 0.01), with odds ratio 5.2 (2.4-11.3) for SOA > 140 degrees.

CONCLUSIONS

Iliopsoas hip snapping is often part of a more complex disease process. While challenging to diagnose, advanced imaging parameters, like the sagittal opening angle, relate with clinical pathology. The SOA offers diagnostic value, with a threshold of greater than 140 degrees significantly correlating with clinical presentation.

The Extension-Thickness-Damage (ETD) score: a pre-operative hip MR arthrography-based classification to predict type of labrum surgery

INTRODUCTION

Hip magnetic resonance arthrography (MRA) is the pre-operative imaging modality of choice in patients with labral damage, with several classifications of labral tears having been reported based on MRA findings. Nevertheless, none of the available classification systems allows the surgeon to predict before surgery how a labral tear could be treated. Our purpose was to develop a new MRA-based scoring system of labral tears to predict before surgery the treatment option more suitable for labral tears.

MATERIALS AND METHODS

Forty-seven patients (29 males and 18 females; mean age: 35.9 ± 12.4) performed hip MRA for suspicious of femoroacetabular impingement and were afterwards subjected to arthroscopic treatment. Two musculoskeletal radiologists reviewed all pre-operative examinations and provided the Extension-Thickness-Damage score for each patient, based on Extension of tear, Thickness of labrum, and type of Damage. Chondral lesions grading was based on the arthroscopic findings according to Konan classification. For statistical purposes, patients were divided into two groups, depending on the type of treatment: labral repair or debridement. Mann-Whitney U, Chi-square, receiver operator curves, and Cohen kappa statistics were used.

RESULTS

35/47 underwent repair, while 12/47 were debrided. In both groups, the median chondral damage was grade III, with no significant differences (p = 0.439). The median Extension-Thickness-Damage score in the repair group (6) was significantly lower (p < 0.001) than that in the debridement group (8). The highest diagnostic performance (area under the curve) of Extension-Thickness-Damage was 0.819. The inter-observer agreement was substantial in the evaluation of Extension (k = 0.626) and Thickness (k = 0.771), and almost perfect for Damage (k = 0.827). Higher scores of Extension and Thickness were more frequently associated with debridement (p < 0.001; p = 0.0016, respectively), with no significant differences on the basis of Damage parameter (p = 0.284).

CONCLUSIONS

The MRA-based Extension-Thickness-Damage score could represent a helpful pre-operative tool, expressing the extent of the damage and its reparability before arthroscopy.

Diagnosis and treatment of labral tear

Objective:

To review the literature regarding diagnosis and treatment of labral tear.

Data sources:

A systematic search was performed in PubMed using various search terms and their combinations including hip, labrum, acetabular labral tear, arthroscopy, diagnosis, and anatomy.

Study selection:

For each included study, information regarding anatomy, function, etiology, diagnosis, and management of acetabular labral tear was extracted.

Results:

Five hundred and sixty abstracts about anatomy, function, etiology, diagnosis, and management of acetabular labral tear were reviewed and 66 selected for full-text review. The mechanism of labral tear has been well explained while the long-term outcomes of various treatment remains unknown.

Conclusions:

Labral tear is generally secondary to femoroacetabular impingement, trauma, dysplasia, capsular laxity, and degeneration. Patients with labral tear complain about anterior hip or groin pain most commonly with a most consistent physical examination called positive anterior hip impingement test. Magnetic resonance arthrography is a reliable radiographic examination with arthroscopy being the gold standard. Conservative treatment consists of rest, non-steroidal anti-inflammatory medication, pain medications, modification of activities, physical therapy, and intra-articular injection. When fail to respond to conservative treatment, surgical treatment including labral debridement, labral repair, and labral reconstruction is often indicated.

High frequency of labral pathology in symptomatic borderline dysplasia: a prospective magnetic resonance arthrography study of 99 patients

Labral pathology is seen in both dysplastic and borderline dysplastic hips. Periacetabular osteotomy (PAO) is the treatment of choice for dysplasia. However, some authors have suggested that borderline dysplastic hips with concurrent labral pathology should be treated arthroscopically. The purpose of this study was to investigate the frequency of labral pathology between dysplastic and borderline dysplastic hips, whether centre-edge (CE) angle is associated with labral pathology, and finally if pain and labral pathology are associated. Ninety-nine symptomatic patients (104 hips) scheduled for PAO were examined. Five patients were excluded due to complaints from multiple joints and four failed to show at 2-year follow-up. Five patients did not fill out questionnaires preoperatively. Hips were characterized as dysplastic (CE angle <20°) and borderline dysplastic (CE angle 20° ≤ 25°). A magnetic resonance arthrography was performed, and labral pathology was classified according to the Czerny classification. Association with the CE angle, the acetabular index (AI) and preoperative WOMAC pain score was tested by multiple linear regression. There was no significant difference in frequency of labral pathology when comparing the two groups. Across the cohort, 86 of 99 patients had labral pathology. The CE angle was associated with increasing severity of labral pathology, whereas the AI angle and preoperative pain were not associated with labral pathology. Decreased lateral coverage adversely loads the labrum, predisposing it to tears. We advocate reorienting the biomechanical forces through PAO, not arthroscopic treatment. Level of pain was not associated with labral pathology, suggesting that labral pathology may not alone explain the dysplastic pain complex.

Accuracy of Magnetic Resonance Imaging and Computed Tomography Arthrography in Diagnosing Acetabular Labral Tears and Chondral Lesions

Background

We investigated sensitivity, specificity, and accuracy of magnetic resonance imaging (MRI) and computed tomography arthrography (CTA), on the basis of arthroscopic findings, to diagnose acetabular labral tears and chondral lesions.

Methods

We retrospectively reviewed the results of MRI and subsequent CTA in 36 hips that underwent arthroscopic surgery (33 patients; 17 males [17 hips] and 16 females [19 hips]; average age, 35 years). All patients had positive impingement test results and groin pain. We analyzed sensitivity, specificity, and accuracy of MRI and CTA by comparing with the arthroscopic findings. Interobserver agreement and intraobserver reproducibility of the presence of tears and cartilage lesions on MRI and CTA were calculated using Kappa coefficients.

Results

The sensitivity, specificity, and accuracy of MRI for detection of acetabular labral tears by two observers were 60%, 80%, and 64%, respectively, and 65%, 70%, and 69%, respectively. The sensitivity, specificity, and accuracy of CTA for detection of labral tears by both observers were 85%, 90%, and 86%, respectively, and 92%, 80%, and 89%, respectively. However, the sensitivity and specificity of MRI for detection of acetabular chondral lesions by both observers were 36% and 84%, respectively, and 46% and 88%, respectively. The sensitivity and specificity of CTA for detecting acetabular cartilage lesions by both observers were 46% and 72%, respectively, and 64% and 72%, respectively. Intraobserver reproducibility for detection of labral tears and chondral lesions by using MRI was substantial (κ = 0.756 and κ = 0.693, respectively). Interobserver reliability for detection of labral tears and chondral lesions by using MRI was substantial (κ = 0.700 and κ = 0.875, respectively). Intraobserver reproducibility for detection of labral tears and chondral lesions by using CTA was substantial (κ = 0.832 and κ = 0.774, respectively). Interobserver reliability for detection of labral tears and chondral lesions by using CTA was high (κ = 0.886 and κ = 0.596, respectively).

Conclusions

This study demonstrated that the accuracy of MRI to detect an acetabular labral tear and a chondral lesion of the hip joint was not sufficient. CTA was reliable in the diagnosis of acetabular labral tears. However, both CTA and MRI were also of limited value to detect chondral lesions.

Arthroscopic Repair of Acetabular Labral Tears Associated with Femoroacetabular Impingement: 7-10 Years of Long-Term Follow-up Results

Background

The purpose of this study is to report the long-term follow-up results of arthroscopic repair of acetabular labral tears with femoroacetabular impingement (FAI).

Methods

Of 45 patients who underwent arthroscopic labral repair under the diagnosis of acetabular labral tears with FAI from January 2008 to December 2010 and met our inclusion criteria, 41 patients who were available for a long-term follow-up were included in the analysis. We compared the long-term follow-up results with the previously reported short-term follow-up results of the same patients. The mean follow-up period was 92.4 months (range, 85 to 117 months). There were 21 males and 20 females, and their mean age at surgery was 34.6 years (range, 16 to 54 years). A modified Harris hip score (mHHS), visual analog scale (VAS), hip outcome score-activity of daily living (HOS-ADL), hip outcome score-activity-sport-specific subscale (HOS-SSS), and patient satisfaction were used for evaluation of the clinical results and Tönnis grade for detection of early osteoarthritis (OA).

Results

The mean VAS score decreased from 6.4 points to 1.8 points (p < 0.001), the mean mHHS increased from 59.5 points to 86.8 points (p < 0.001), and the mean HOS-ADL and HOS-SSS increased from 58.3 and 51.2, respectively, to 85.2 and 82.4, respectively (p < 0.001), between the preoperative and last follow-up assessment. The mean patient satisfaction score was 7.6 of 10. The average Tönnis grade at the last follow-up (0.67; range, 0 to 3) was not significantly different from the preoperative average (0.51; range, 0 to 1). Only one case was converted to total hip arthroplasty because of progression of OA at 8 years after surgery. Five cases of secondary arthroscopic surgery were performed before maximum 5 years postoperatively because of labro-synovial adhesion (three cases), pullout of the suture anchor (one case) or symptomatic heterotrophic ossification (one case).

Conclusions

The clinical and radiological long-term follow-up revealed that improvement after arthroscopic labral repair and osteoplasty for FAI were maintained in most cases without significant progression of arthritis. Anatomical recovery of the acetabular labrum was associated with the improvement of clinical symptoms.

[Femoroacetabular impingement - Update 2019]

BACKGROUND

Since the first description of the femoroacetabular impingement (FAI) concept diagnostic imaging of FAI has continuously been developed.

OBJECTIVE

The biomechanical concept is explained and an update on diagnostic imaging of FAI is presented.

MATERIAL AND METHODS

Based on a literature search this review article presents the current state of knowledge about FAI mechanisms and gives an overview on state of the art radiological diagnostics. A perspective on new imaging methods is also given.

RESULTS

The FAI is a dynamic phenomenon with a mechanical conflict between the femoral head and/or neck and the acetabulum. It is usually suspected clinically; however, imaging plays an essential role in establishing the diagnosis by detecting and defining the underlying deformities of the proximal femur (cam deformity) and the acetabulum (pincer deformity) and by evaluating associated lesions of the articular cartilage and labrum. Basic imaging diagnostics consist of anteroposterior and lateral radiographs. Magnetic resonance imaging (MRI) and MR arthrography are the preferred imaging modalities for detailed analysis of deformities, for the detection and graduation of lesions of articular cartilage (sensitivity 58-91%) and labral lesions (sensitivity 50-92%). Simultaneously, these methods can exclude other hip diseases. Current standards and new developments in FAI imaging are presented.

CONCLUSION

For the diagnosis of FAI typical clinical and imaging findings are required. Radiological diagnostics are an indispensable component in establishing the diagnosis of FAI, in the differentiation of the underlying deformities and in the assessment of treatment-relevant joint damage.

[Labral pathologies of the hip joint]

Magnetic resonance imaging (MRI) of the hip joint is performed for the diagnostics of many clinical pathologies. For clarification of pathologies of the hip joint conventional MRI and MR arthrography are used. The use of MRI either with or without the intravenous administration of contrast material is performed to diagnose bone marrow lesions, necrosis of the femoral head, inflammatory and tumorous lesions affecting the hip joint and its components. After the intra-articular administration of a diluted solution of contrast material, which results in distension of the joint, MR arthrography is performed for the diagnosis of intra-articular pathologies, such as lesions of the labrum acetabulare, chondral lesions and free intra-articular bodies. In recent times, MR arthrography is carried out with continuous traction of the limb to be examined because this leads to a distension of the joint and its components and in this way particularly lesions of the labrum with involvement of cartilage can be visualized even better. This article gives an overview of MRI and the accuracy of detecting lesions of the labrum acetabulare and the influence on the therapeutic approach.

Dynamic shear analysis: a novel method to determine mechanical integrity of normal and torn human acetabular labra: Implications for prediction of outcome of repair

Objectives

The aim of this study was to investigate the structural integrity of torn and non-torn human acetabular labral tissue.

Methods

A total of 47 human labral specimens were obtained from a biobank. These included 22 torn specimens and 25 control specimens from patients undergoing total hip arthroplasty with macroscopically normal labra. The specimens underwent dynamic shear analysis using a rheometer to measure storage modulus, as an indicator of structural integrity.

Results

There was a significant difference in the storage modulus between torn (mean modulus = 2144.08 Pa) and non-torn (3178.1 Pa) labra (p = 0.0001).

Conclusion

The acetabular labrum of young patients with a tear has significantly reduced structural integrity compared with a non-torn labrum in older patients with end-stage osteoarthritis. This study contributes to the understanding of the biomechanics of labral tears, and the observation of reduced structural integrity in torn labra may explain why some repairs fail. Our data demonstrate that labral tears probably have a relatively narrow phenotype, presenting a basis for further investigations that will provide quantifiable data to support their classification and a means to develop a standardized surgical technique for their repair. This study also demonstrates the value of novel biomechanical testing methods in investigating pathological tissues of orthopaedic interest.Cite this article: A. K. Woods, J. Broomfield, P. Monk, F. Vollrath, S. Glyn-Jones. Dynamic shear analysis: a novel method to determine mechanical integrity of normal and torn human acetabular labra: Implications for prediction of outcome of repair. Bone Joint Res 2018;7:440-446. DOI: 10.1302/2046-3758.77.BJR-2017-0282.R2.

Factors increasing risk of failure following hip arthroscopy: a case control study

We aimed to identify factors such as pre-arthroscopy and intra-operative variables that were associated with failure of hip arthroscopy as a joint preserving operation. We performed a retrospective analysis of a database containing 344 consecutive hip arthroscopies performed at our institution. Forty-four hips were identified that underwent a subsequent arthroplasty procedure following their hip arthroscopy (cases). Sixty-six control hips (hip arthroscopy with no subsequent arthroplasty) were randomly selected from the same database. Cases and controls were matched for age, sex and follow-up (P = 0.59, 0.48, 0.10, respectively). Pre-operative radiographs/MRI scans plus intra-operative findings were analysed to identify factors associated with failure. Both a lower centre edge angle and higher acetabular index on pre-operative radiographs were associated with higher rates of failure (P < 0.001). The presence of any acetabular wear at operation was also associated with failure (P < 0.001). Highest rates of failure were seen in hips with both features of dysplasia on pre-operative radiographs and any intra-operative acetabular wear (relative risk: 5, odds ratio: 9.13, P < 0.001). Dysplastic features on pre-operative radiographs and the finding of acetabular wear at hip arthroscopy increase the risk of subsequent arthroplasty. Identification of these features pre-operatively with evolving imaging techniques would improve the results of hip arthroscopy as joint preserving surgery.

Clinical outcomes of arthroscopic repair of acetabular labral tears

Purpose

To evaluate the primary clinical outcomes of arthroscopic labral repair.

Methods

All patients who underwent arthroscopic repair of the acetabular labrum performed by a senior surgeon between October 2010 and December 2013 were invited to participate in this prospective study. Patients included were those who had a preoperative diagnosis of labral tears, a lateral centre edge greater than 25° and a labral tear believed to be suturable during the intraoperative evaluation. Patients with Tönnis grade 2 or grade 3 hip osteoarthritis and those who had undergone a previous hip surgery were excluded. All patients were evaluated using the modified Harris Hip Score (mHHS) during the final appointment before surgery, 4 months after surgery and at the final evaluation. Interviews were conducted by the senior surgeon.

Results

Eighty-four patients (90 hips) underwent arthroscopic repair. The mean age was 44.2 years and the mean follow-up period was 43.0 months (minimum of 25 months and maximum of 59 months). The mean mHHS was 80.4 preoperatively, 95.0 at 4 months postoperatively and 96.6 at final evaluation. A statistically significant difference existed among these scores (p<0.001).

Conclusion

Arthroscopic labral repair was associated with a clinically significant improvement in mHHS after short-term (4 months) and medium-term (43 months) follow-up.

Level of evidence

Level IV, therapeutic case series.

Femoroacetabular impingement: a common cause of hip pain

Femoroacetabular impingement (FAI) is a common cause of hip pain that can affect a wide range of patients. It is due to altered bony morphology of the proximal femur and acetabulum, resulting in decreased function and progression to early osteoarthritis. Until the early 2000s, little was known or understood about the significance of FAI as a clinical entity. The field of hip preservation has grown exponentially since that time, and has led to many advances in caring for those with symptomatic impingement. This review details the early diagnosis and proper management of femoroacetabular impingement for the sports medicine practitioner.