The imaging evaluation of acetabular labral lesions

The patellar compression angle: a new, accurate diagnostic angle for lateral patellar compression syndrome

BACKGROUND

Lateral patellar compression syndrome (LPCS) is a common cause of anterior knee pain. Early diagnosis of LPCS using an accurate radiological examination is, therefore, important. However, the currently used radiological examinations for detecting LPCS are poor diagnostic indicators. Therefore, the aim of this study was to establish a new diagnostic imaging examination for LPCS and evaluate its accuracy in comparison with conventional examinations.

METHODS

From June 2020 to May 2023, a retrospective analysis was conducted on 72 patients in the LPCS group and 140 patients in the Control group, all of whom underwent axial radiographs of the patella and knee MRI. The patellar compression angle (PCA), Tilting angle (TA), Congruence angle (CA), Grelsamer angle (AG), and Lateral patellofemoral angle (LPA) were used and compared statistically for their accuracy in terms of diagnosing LPCS.

RESULTS

The area under the receiver operating characteristic curve (ROC) for the PCA was 0.87, which was the highest among the five examinations. ROC analysis revealed that a smaller PCA, less than 14.7°, was associated with LPCS, with the highest sensitivity (80.6%), specificity (82.9%), accuracy (82.1%), positive predictive value (PPV, 70.7%), negative predictive value (NPV, 89.2%), positive likelihood ratio (PLR, 4.71), and lowest negative likelihood ratio (NLR, 0.23) compared with the other four examinations. The interobserver reproducibility of the PCA was good, with an intraclass correlation coefficients (ICCs) of 0.85.

CONCLUSIONS

The PCA can detect LPCS with a moderate diagnostic performance and could, therefore, might be a new angle for the diagnosis of LPCS in clinical settings.

Postoperative femoral head cartilage injury after hip arthroscopic treatment for femoroacetabular impingement syndrome and labral tear

BACKGROUND

Postoperative femoral head cartilage injury (FHCI) is a rare condition that can be observed in a certain proportion of patients undergoing hip arthroscopy. However, the prevalence and associated factors of FHCI, and the effect of this condition on clinical outcomes still remain unknown.

PATIENTS AND METHODS

Consecutive patients who were diagnosed with femoroacetabular impingement syndrome (FAIS) and labral tear and underwent hip arthroscopic treatment in our institute between July 2020 and July 2021 were retrospectively evaluated. Supine anteroposterior hip radiographs, cross-table lateral radiographs, magnetic resonance imaging (MRI), and computed tomography (CT) were obtained preoperatively. Postoperative MRI, at least 6 months after arthroscopy, was performed. Postoperative FHCI was evaluated by two surgeons through MRI. Preoperative patient-reported outcomes (PROs) including visual analog scale (VAS) for pain, and modified Harris Hip Score (mHHS) before surgery and at final followup were obtained.

RESULTS

A total of 196 patients were included. Postoperative FHCI was identified in 21 (10.7%) patients. The intraobserver reliability of the observer A and B for detecting postoperative FHCI using 3.0-T MRI was high (k = 0.929, and k = 0.947, respectively). The interobserver reliability between the two observers for detecting FHCI using 3.0-T MRI was high (k = 0.919). There was no significant difference in preoperative and postoperative mHHS, VAS, and percentage of patients who surpassed minimal clinically important difference (MCID) and achieved patient acceptable symptom state (PASS) between patients with and without postoperative FHCI (P > 0.05).

CONCLUSION

Although postoperative FHCI was observed in 10.7% of patients, which was associated with larger labrum, this condition did not result in inferior clinical outcomes. Level of evidence IV, retrospective case series. Trial registration The Chinese Clinical Trial Registry approved the registration (ChiCTR2200061166). The date of registration is 2022-06-15.

Bibliometric analysis of the acetabular labrum

The acetabular labrum (AL) plays a crucial role in the normal physiological functioning of the hip joint. This study aims to present an overview of the current status and research hotspots concerning the AL and to explore the field from a bibliometric perspective. A total of 1918 AL-related records published between January 1, 2000 and November 8, 2023 were gathered from the Web of Science Core Collection database. By utilizing tools such as HisCite, CiteSpace, VOSviewer, and the R package "bibliometrix," the regions, institutions, journals, authors, and keywords were analyzed to predict the latest trends in AL research. Global research interest and publication output related to this topic continues to escalate. The United States leads in international collaborations, number of publications, and citation frequency, underscoring its preeminent position in this field. The American Hip Institute emerged as the most prolific institution, making the greatest contribution to publications. Notably, Arthroscopy and the American Journal of Sports Medicine are the 2 most popular journals in this domain, accounting for 13.29% and 10.1% of publications, respectively, and were also found to be the most co-cited journals. Amongst authors, Benjamin G. Domb leads with 160 articles (8.35%), while Marc J. Philippon is the most frequently cited author. The keyword co-occurrence network showed 3 hot clusters, including "AL," "femoral acetabular impingement (FAI)," and "osteoarthritis." In addition, "survivorship," "FAI," and "patient-reported outcomes" were identified as trending topics for future exploration. This study represents the first comprehensive bibliometric analysis, summarizing the present state and future trends in AL research. The findings serve as a valuable resource for scholars, offering practical insights into key information within the field and identifying potential research frontiers and emerging directions in the near future.

Update on contribution of hip labral tears to hip pain: A narrative review

Hip labral tears are found in 22-55% of individuals with hip pain, but labral tears without cysts are usually not responsible for hip pain, which originates mostly from other structures than the torn labrum, like osteochondral, but also tendinous injuries (rectus femoris, gluteus minimus, iliopsoas) or capsulo-ligamentous tears (iliofemoral ligaments, ligament teres). Those lesions are mainly the consequences of underlying unrecognized functional acetabular dysplasia, and/or femoroacetabular impingements. Although the early repair of labral tears in young sportsmen induces a marked and lasting relief, and might delay the onset of osteoarthritis, the microinstability fostered by labral damages seems less important than underlying dysplasias/impingements. This narrative review details recent findings on: (i) the various mechanisms of pain associated with labral tears; (ii) few evidence for hip microinstability induced by isolated labral tears; (iii) how to best detect labral tears, both clinically (including through IROP test) and on imaging (MRI, MRA, computed tomography arthrography, ultrasound). Some authors suggested to use pull-out tests during surgery, but pulling of hips do not seem to increase much diagnostic performances of ultrasounds. Ultrasound-guided intra-articular and peri-articular injections may tell how often hip pain is exclusively induced by peri-capsular injuries secondary to the acetabular dysplasia/femoro-acetabular impingements already responsible for labral tears. Further works could tell whether labral repair, tendinous debridement, plication of capsule, and/or focal denervation, may induce lasting reliefs of pain induced by the chronic contraction of surrounding muscles (rectus femoris, gluteus minimus, psoas), whose deep aponeuroses mix with the superficial fibres of the thick hip capsule.

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.