Relationship between acetabular labrum evaluation by using radial magnetic resonance imaging and progressive joint space narrowing in mild hip dysplasia

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.

Relationship between labral length and symptoms in patients with acetabular dysplasia before rotational acetabular osteotomy

The aim of this study was to investigate the relationship between acetabular labral length and symptoms in patients with acetabular dysplasia. In a retrospective medical record review, 218 patients with acetabular dysplasia who had undergone rotational acetabular osteotomy were identified. After implementing the inclusion and exclusion criteria, 53 patients were analyzed for preoperative symptoms measured by the Japanese Orthopaedic Association Hip Disease Evaluation Questionnaire (JHEQ), acetabular bone morphology parameters by anteroposterior pelvic radiographs and labral parameters by radial magnetic resonance imaging. Spearman's correlation coefficients were calculated among JHEQ scores, bone morphologic parameters and labral parameters. Multiple linear regression models to determine the predictive variables of JHEQ score and labral length were obtained. There was no correlation between bone morphologic parameters and JHEQ scores. Labral length measured anteriorly correlated with JHEQ pain {r [95% confidence interval (CI)] = -0.335 (-0.555, -0.071), P = 0.014}, movement subscale [r (95% CI) = -0.398 (-0.603, -0.143), P = 0.003], mental subscale [r (95% CI) = -0.436 (-0.632, -0.188), P = 0.001] and total JHEQ score [r (95% CI) = -0.451 (-0.642, -0.204), P = 0.001]. The multiple linear regression results showed that anterior labral length was independently associated with JHEQ subscales in some models. Meanwhile, age, acetabular head index and total JHEQ score were independently associated with anterior labral length in all models. Labral length, notably in anterosuperior area, in patients with symptomatic acetabular dysplasia was related to patient's symptom. Labral length may be an important objective image finding that can be used to assess the severity of cumulative hip instability.

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.

Evaluation and Treatment of Borderline Dysplasia: Moving Beyond the Lateral Center Edge Angle

PURPOSE OF REVIEW

The purpose of this manuscript is to 1 define the features associated with borderline acetabular dysplasia and 2 review current status of diagnostic algorithms and treatment options for borderline dysplasia.

RECENT FINDINGS

Acetabular dysplasia is a common cause of hip pain secondary to insufficient coverage of the femoral head by the bony acetabulum. Historical classification of acetabular dysplasia has utilized the lateral center edge angle (LCEA); values above 25° are normal and below 20° are considered pathologic. Borderline dysplasia describes hips with LCEA between 20 and 25^o; treatment of these patients is controversial. While many studies utilize LCEA in classification of borderline dysplasia, isolated reliance on measurement of lateral femoral head coverage to define severity of undercoverage will continue to mislabel morphology. Thorough assessment of the characteristics of mild acetabular undercoverage is necessary for future studies, which will allow effective comparisons of results between hip arthroscopy and periacetabular osteotomy.

Bone maturation of MRI residual developmental dysplasia of the hip with discrepancy between osseous and cartilaginous acetabular index

Quality of spontaneous amelioration of residual developmental dysplasia of the hip (DDH) is nowadays not possible to predict. Normal age-related values of the osseous acetabular index (OAI), cartilaginous acetabular index and labral acetabular index have been established on MRI. In this study, MRI of dysplastic hips has been evaluated, and further osseous acetabular maturation was followed-up over time on pelvic radiography to find a correlation between MRI findings and radiological evolution. This is a retrospective single-centre study. Children with DDH who had a pelvic MRI between February 2007 and June 2014 were included. AI was measured for osseous (OAI), cartilaginous (cartilaginous acetabular index) and labral (labral acetabular index) values on MRI. OAI was thereafter recorded on each available radiograph during follow-up. A total of 20 hips were included. The mean age at MRI diagnosis was 3.55 years. Two types of DDH were observed: harmonious dysplasia, associated with an osseous and cartilaginous defect (group A, n = 14), and divergent dysplasia, associated with an osseous defect but with sufficient cartilaginous coverage (group B, n = 6). The mean age at final radiological follow-up was 7.6 and 8.3 years (P = 0.7408), respectively. In group A, four (28.6%) children older than 6 years had an OAI of less than 18°, whereas only two (33.3%) children older than 6 years had an OAI less than 18° in group B (P = 0.0117). This study shows that, in one-third of cases, divergent dysplasia leads to a spontaneous recovery. MRI should be used early to accurately diagnose and follow-up DDH cases and allow surgeons to justify the required surgical treatment. Level of Evidence: IV.

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.

Imaging of non-osteochondral tissues in osteoarthritis

OBJECTIVE

The aim of this review is to describe imaging techniques for evaluation of non-osteochondral structures such as the synovium, menisci in the knee, labrum in the hip, ligaments and muscles and to review the literature from recent clinical and epidemiological studies of OA.

METHODS

This is a non-systematic narrative review of published literature on imaging of non-osteochondral tissues in OA. PubMed and MEDLINE search for articles published up to 2014, using the keywords osteoarthritis, synovitis, meniscus, labrum, ligaments, plica, muscles, magnetic resonance imaging (MRI), ultrasound, computed tomography (CT), scintigraphy, and positron emission tomography (PET).

RESULTS

Published literature showed imaging of non-osteochondral tissues in OA relies primarily on MRI and ultrasound. The use of semiquantitative and quantitative imaging biomarkers of non-osteochondral tissues in clinical and epidemiological OA studies is reported. We highlight studies that have compared both imaging methodologies directly, and those that have established a relationship between imaging biomarkers and clinical outcomes. We provide recommendations as to which imaging protocols should be used to assess disease-specific changes regarding synovium, meniscus in the knee, labrum in the hip, and ligaments, and highlight potential pitfalls in their usage.

CONCLUSION

MRI and ultrasound are currently the most useful imaging modalities for evaluation of non-osteochondral tissues in OA. MRI evaluation of any tissue needs to be performed using appropriate MR pulse sequences. Ultrasound may be particularly useful for evaluation of small joints of the hand. Nuclear medicine and CT play a limited role in imaging of non-osteochondral tissues in OA.

Anterior impingement test for labral lesions has high positive predictive value

BACKGROUND

The anterior impingement test is intended to detect anterosuperior acetabular labral lesions. In patients treated for labral lesions its sensitivity is reportedly 95% to 100%, and in a small group of patients undergoing periacetabular osteotomy, its sensitivity was 59% and specificity 100%. However, the sensitivity, specificity, positive predictive value, and negative predict value of this test to detect these labral lesions in unselected patients with hip pain are unknown.

QUESTIONS/PURPOSES

We investigated these four parameters (1) in unselected patients with hip pain, and (2) in three subgroups of patients with dysplasia, femoroacetabular impingement (FAI), and with an intact joint space.

METHODS

We prospectively studied 69 patients (15 men and 54 women) with a mean age of 57.2 years (range, 27-81 years). One observer performed the anterior impingement test in all patients. We determined the presence or absence of an anterosuperior labral lesion with radial MRI in 107 hips (38 patients in both hips: 14 with pain, and 24 without pain). We also investigated the parameters in the three subgroups which consisted of 60 cases of dysplasia, 27 cases of FAI, and 80 cases with intact joint space; the third subgroup partially overlapped the first and second subgroups.

RESULTS

The four parameters in all hips were 50.6% (45/89), 88.9% (16/18), 95.7% (45/47), and 26.7% (16/60), respectively. Parameters in the three subgroups were similar to those of all cases.

CONCLUSIONS

Although the sensitivity of the anterior impingement test did not reach a sufficient level for detecting anterosuperior labral lesions, we believe the high positive predictive value makes the test useful.

LEVEL OF EVIDENCE

Level III, diagnostic study. See the Guidelines for Authors for a complete description of levels of evidence.

MR-based parameters as a supplement to radiographs in managing developmental hip dysplasia

BACKGROUND

Some dysplastic hips with favorable radiographic parameters fail to develop normally, suggesting that we should consider cartilaginous or soft tissue structures for further information regarding the condition of the hip. The purpose of this study was to provide a clear definition of concentric reduction in developmental dysplasia of the hip (DDH) based on magnetic resonance imaging (MRI), and to determine how radiographic and MR-based parameters could be used together to treat dysplastic hips.

METHODS

We studied range of motion (ROM)-MRI of 25 patients with unilateral hip dysplasia (mean age at the time of MR imaging, 44.1 months). Each ROM-MRI consisted of a set of bilateral hip scans in the following positions: neutral; abduction; abduction- internal rotation; abduction-internal rotation-flexion; and adduction. Before MR scanning, the 25 patients received the following primary treatments: closed reduction (n = 15; at a mean age of 14.5 months); and open reduction (n = 10; at a mean age of 10.0 months). The following new parameters appear to be useful in treating DDH: 1) the labral angle, the angle the labrum makes with the acetabulum; 2) the uncorrected labral deformity (ULD), the "residual deformity" (deflection of the labrum) when the affected labrum is freed from pressure in abduction; and 3) the zone of compressive force (ZCF), the region of the acetabulum through which the body weight acts on the femoral head.

RESULTS

A concentrically-reduced hip is one in which the labrum points downward in the neutral position, at the same angle as that of the normal side; and in which the ZCF is zone 3, the inner acetabular zone as defined herein. The ULD and the ZCF may be determined precisely as we have done, or the physician may simply observe the changes in the orientation of the labrum and compare the changes qualitatively to the unaffected side, and likewise for the medial joint space.

CONCLUSIONS

Detailed analysis of the labrum as permitted by ROM-MRI, together with acetabular index and other parameters measured from radiographs, provides important information for physicians treating childhood hip dysplasia.

Hip Osteoarthritis MRI Scoring System (HOAMS): reliability and associations with radiographic and clinical findings

OBJECTIVE

To develop a semiquantitative MRI-based scoring system (HOAMS) of hip osteoarthritis (OA) and test its reliability and validity.

DESIGN

Fifty-two patients with chronic hip pain were included. 1.5T magnetic resonance imaging (MRI) was performed on all patients. Pelvic radiographs were scored according to the Kellgren-Lawrence (KL) system. Clinical outcomes were assessed by the hip osteoarthritis outcome score (HOOS). MRIs were analyzed using a novel whole-joint MRI score that incorporated 13 articular features. Reliability was determined on a random subset of 15 cases. Weighted-kappa statistics and overall agreement were used as a measure of intra- and inter-observer reliability. Associations between MRI features and radiographic OA severity were calculated using Cochran-Armitage test for trend. Ordinal logistic regression was used to assess associations between MRI features and severity of pain and functional limitation.

RESULTS

Distribution of radiographic grading was: KL 0=12 (27%), KL 1=11 (25%), KL 2=14 (32%), KL 3=5 (11%) and KL 4=2 (5%). Intra-reader reliability for the different features ranged from 0.18 (cysts) to 0.85 (cartilage). Inter-reader reliability ranged between 0.15 (cysts) and 0.85 (BMLs). Low kappas were due to low frequencies of some features as overall percent agreement was good to excellent (83.8% and 83.1%). There was a strong association between MRI-detected lesions and radiographic severity (P=0.002). Non-significant trends were observed between MRI features and clinical outcomes.

CONCLUSION

MRI-based semiquantitative assessment of the hip shows adequate reliability. Presence of more severe MRI-detected intraarticular pathology shows a strong association with radiographic OA. The results suggest possible associations between MRI-detected pathology and clinical symptoms.