Hip arthroscopy-MRI correlation and differences for hip anatomy and pathology: What radiologists need to know

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.

Training surgical skills on hip arthroscopy by simulation: a survey on surgeon's perspectives

Purpose

The purpose of this study is to investigate the importance of general and specific surgical skills for hip arthroscopy from the perspective of surgeons in China. Concurrently, we intend to identify the preferred type of simulation that would facilitate competency of surgical trainees in performing arthroscopy and reinforce their preparation for carrying out the actual surgical procedure.

Methods

An online survey comprising 42 questions was developed by experts in hip arthroscopy and sent to 3 online communities whose members are arthroscopic surgeons in China. The responses collected were based on a 5-point Likert scale, with an open-ended comment section. Data were analyzed using one-way AVOVA and post hoc Tukey’s test.

Results

A total of 159 valid responses from 66 junior specialist surgeons, 68 consultant surgeons, and 25 senior consultant surgeons (from 130 institutions in 27 out of 34 provincial administrative districts in China) were collected. Cognitive ability was identified as the overall most important attribute for hip arthroscopic trainees to possess, while skills relevant to the treatment of femoroacetabular impingement (FAI) were considered as the most important specific skills by the surgeons surveyed. In addition, simulation using cadaveric specimens was considered the most favorable method for surgeons to practice their surgical skills.

Conclusion

In designing a training program for hip arthroscopy, it is essential to incorporate features that evaluate cognitive skills. It would be helpful for trainees to specifically practice skills that are often used in the treatment of some very common diseases of the hip joint, such as FAI. Using high-fidelity physical models for simulation to train skills of hip arthroscopy could be an ideal alternative and effective way to overcome problems arising from the lack of accessibility to cadaveric specimens.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11548-022-02708-x.

Deep gluteal space anatomy and its relationship with deep gluteal pain syndromes

INTRODUCTION

Increasing interest has been seen in understanding the anatomy and biomechanics involved in the Deep Gluteal Syndrome, therefore the main objective of our paper was to define the anatomy of the deep gluteal space concerning the important osseous, muscular and neurological structures.

METHODS

12 cadaveric models (24 hemipelvises) were used. We proceeded with classical anatomic dissection and evaluated numerous osseous, musculotendinous and neurologic structures and their relationships. We also determined the femoral anteversion and neck-shaft angles.

RESULTS

We found that 15.4% of lower limbs examined presented variations in the sciatic nerve (SN) emergence, and this was significantly longer in men. The distance from the SN to the trochanteric region was also significantly lower in males.The average ischiofemoral distance (IFD) was 2.5 ± 1.3 cm, at the same time that the structures comprised in that space showed superior areas, such as the quadratus femoris (QF) with 5.0 ± 1.1 cm and the SN with 1.4 ± 0.3 cm widths.Besides that, we also evaluated the distance from the SN to the lesser trochanter (LT) and the ischial tuberosity (IT), in the ischiofemoral space, reaching average values of 1.1 ± 0.7 cm and 1.5 ± 0.6 cm respectively.Regarding the relationship between the proximal hamstring insertion, we verified that the LT was at an average distance of 1.6 ± 1.1 cm, that the SN was only 0.2 ± 0.3 cm lateral to it, and the PN is just 2.6 ± 1.2 cm proximal to it.

CONCLUSIONS

Our study confirmed the extreme variation in the SN origin that can contribute to the Piriformis syndrome. The IFD obtained in our study showed that this distance was small for the structures contained in this space.The proximal hamstring insertion showed a significantly more extended footprint in males, which puts the pudendal nerve (PN) at higher risk of iatrogenic injury.

Postoperative Musculoskeletal Imaging and Interventions Following Hip Preservation Surgery, Deformity Correction, and Hip Arthroplasty

Total hip arthroplasty and hip preservation surgeries have substantially increased over the past few decades. Musculoskeletal imaging and interventions are cornerstones of comprehensive postoperative care and surveillance in patients undergoing established and more recently introduced hip surgeries. Hence the radiologist's role continues to evolve and expand. A strong understanding of hip joint anatomy and biomechanics, surgical procedures, expected normal postoperative imaging appearances, and postoperative complications ensures accurate imaging interpretation, intervention, and optimal patient care. This article presents surgical principles and procedural details pertinent to postoperative imaging evaluation strategies after common hip surgeries, such as radiography, ultrasonography, computed tomography, and magnetic resonance imaging. We review and illustrate the expected postoperative imaging appearances and complications following chondrolabral repair, acetabuloplasty, osteochondroplasty, periacetabular osteotomy, realigning and derotational femoral osteotomies, and hip arthroplasty.

[Research progress in arthroscopic treatment of acetabular labrum injury]

Objective

To review the surgical methods of arthroscopy in the treatment of acetabular labrum injury, and to provide reference for clinical treatment.

Methods

The literature about the surgical methods and clinical results of hip arthroscopy in the treatment of acetabular labrum injury was reviewed and analyzed.

Results

In the early stages of hip arthroscopy, the removal of the torn labrum is the primary treatment option. The current principles of treatment are based on the specific circumstances of a torn labrum, including acetabular labrum debridement, acetabular labrum repair, acetabular labrum reconstruction, and acetabular labrum augmentation.

Conclusion

Hip arthroscopy has become the preferred technique for the treatment of acetabular labrum injury. Labral repair is still the first choice, and labral reconstruction is used when acetabular labrum injury cannot be repaired.

Prevalence of Gluteus Medius Pathology on Magnetic Resonance Imaging in Patients Undergoing Hip Arthroscopy for Femoroacetabular Impingement: Asymptomatic Tears Are Rare, Whereas Tendinosis Is Common

BACKGROUND

There is a paucity of literature on asymptomatic gluteus medius pathology. Moreover, no studies have examined the prevalence of asymptomatic gluteus medius pathology.

PURPOSE

To describe the prevalence of asymptomatic gluteus medius pathology in patients undergoing hip arthroscopy for femoroacetabular impingement.

STUDY DESIGN

Cross-sectional study; Level of evidence, 3.

METHODS

A database search of our institution was performed for patients undergoing hip arthroscopy for labral treatment between February 2008 and January 2019. Patients were included if they had gluteus medius pathology identified through magnetic resonance imaging (MRI). Patients were deemed to be asymptomatic if they lacked greater trochanteric hip tenderness, abductor weakness, a positive Trendelenburg sign, or a positive Trendelenburg gait on physical examination. Patients were excluded if they were unwilling to participate or did not have a documented physical examination or MRI read in the database.

RESULTS

A total of 2851 hips (2452 patients) met the inclusion/exclusion criteria. Gluteus medius pathology was found in 871 hips (30.6%) on MRI. Symptomatic gluteus medius pathology was observed in 414 (14.5%) hips, of which 305 (10.7%) had tendinosis, 99 (3.5%) had partial-thickness tears, and 10 (0.4%) had full-thickness tears. Asymptomatic gluteus medius pathology was observed in 457 (16.0%) hips, of which 408 (14.3%) had tendinosis and 49 (1.7%) had partial-thickness tears. No hips with full-thickness tears on MRI were asymptomatic. Patients with asymptomatic partial-thickness tears were significantly older than those with only tendinosis (45.3 vs 39.4 years, respectively; P = .001). Patients aged 40 years or older had a 2.11 (1.80-2.50) (P < .001) relative risk of asymptomatic pathology compared with patients younger than 40 years.

CONCLUSION

Although there is a meaningful prevalence of asymptomatic gluteus medius tendinosis, the prevalence of asymptomatic gluteus medius tears is low. Treatment of gluteus medius tendinosis should therefore be based not solely on MRI findings but rather on a complete clinical evaluation. In contrast, MRI findings of partial or full-thickness gluteus medius tears may be more likely to have clinical significance.