Classification of intraarticular hip injuries. MR arthrography and arthroscopic correlation.

Classification of intraarticular hip injuries. MR arthrography and arthroscopic correlation. Poster No.: C-2180 Congress: ECR 2015 Type: Educational Exhibit Authors: L. Cerezal, M. Fernández Hernando, L. Pérez-Carro, A. Canga; Santander/ES Keywords: Musculoskeletal joint, MR, Arthrography, Athletic injuries DOI: 10.1594/ecr2015/C-2180 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. www.myesr.org Page 1 of 61

Learning objectives - To review the different classifications and mapping systems of intra-articular hip injuries (labrum, articular cartilage, ligamentum teres, and capsular ligaments injuries). - To provide a correlation of hip MR arthrography with arthroscopic findings in these pathologies. Background MR arthrography is the technique of choice in the assessment of intra-articular hip pathology. MR arthrography with leg traction provides a better assessment of the structures of the central compartment, mainly chondral injuries. Uniformity in terms and classification system is essential for communication between radiologist and arthroscopic surgeons and allows accurate surgical planning. Unfortunately still there are too many systems and little consensus. Images for this section: Page 2 of 61

Fig. 1: Main anatomic structures of the central and peripheral compartment at the origin of intraarticular hip pathology. Page 3 of 61

Fig. 2: Coronal T1-weighted, and T1-fat suppressed images show hypointense areas in the acetabular cartilage in a patient with cam-type FAI, indicating chondral delamination. Page 4 of 61

Fig. 3: Arthroscopic evaluation of the hip is a two-step procedure: flexion without traction for evaluation of the peripheral compartment and extension with traction for evaluation of the central compartment. Page 5 of 61

Fig. 4: Traction device. Photographs show lateral adhesive straps (1) fixed parallel to thigh, leaving 5-cm distance between sole and plate (2), and fixed with bandage (3). System is loaded to 6 kg (4). Distraction is used to improve visualization of the cartilage in the central compartment, and the more central part of the labrum. Page 6 of 61

Fig. 5: Coronal MR arthrography images, with and without leg traction show a massive acetabular chondral delamination ("carpet lesion"). Note that in the MR arthrography without traction most of the contrast media is located in the peripheral compartment and the chondral delamination is not clearly seen. On MR arthrography with traction the contrast fills out the central compartment and nicely show an extensive chondral delamination. Page 7 of 61

Fig. 6: Figure 6. Recommended imaging strategy in the diagnosis of intraarticular hip pathology. Page 8 of 61

Fig. 7: Traumatic labral tear. Illustrative drawing and coronal T1-weigted fat-suppressed image showing a traumatic tear of the antero-superior labrum in a soccer player with history of twisting injury and groin pain and mechanical symptoms at clinical examination. Page 9 of 61

Fig. 8: Classification of femoroacetabular impingement. Page 10 of 61

Fig. 9: Diagrams illustrate the pathomechanics of joint damage in the cam type of FAI. Deformity of the femoral head-neck junction slides into the anterosuperior acetabulum during flexion and induces compression and shear stresses, causing a separation between the labrum and cartilage. Repetitive pathological contact between the femur and acetabulum may lead to a progressive damage of articular structures, mainly articular cartilage. Page 11 of 61

Fig. 10: Diagram illustrates the patterns of damage in the cam impingement. Repetitive pathological contact between the femoral head-neck bump and acetabulum causes a separation between the labrum and cartilage (initial articular injury in cam-type FAI). Page 12 of 61

Fig. 11: Progressive patterns of chondral injury in cam-type FAI. Page 13 of 61

Fig. 12: Diagram illustrates the patomechanics of joint damage in the pincer impingement. The acetabular overcoverage (global-coxa profunda or protusio acetabulior focal- acetabular retroversion) limited the range of movement of the hip. At the limit of movement the femoral neck abuts against the labrum. The main injury in pincer impingement is labral. Cartilage injury is restricted to a narrow band along the acetabular rim. Page 14 of 61

Fig. 13: Progressive patterns of articular injury in pincer-type FAI. The main articular injury in pincer FAI consists in labral degenerative tears. The damage of the articular cartilage is initially limited to the acetabular rim. Most of the lesions are located at the anterosuperior acetabular rim. Page 15 of 61

Fig. 14: Three different examples of pincer type FAI. MR arthrography with arthroscopic correlation images showing fraying, different degrees of atenuation and complex tears of the labrum, and a thin band of condromalacia in the acetabular rim. Page 16 of 61

Fig. 15: "Contrecoup lesion" in pincer FAI. In advanced stages of pincer FAI, the femoral head is chronically leveraged (or subluxated) posteroinferiorly into the acetabular fossa. The increased pressure between the posteroinferior acetabulum and the posteromedial aspect of the femoral head can result in a "contrecoup" lesion to the posterinferior acetabular cartilage and labrum. Page 17 of 61

Fig. 16: Mixed type of FAI. Consecutive MR arthrography images demonstrate a combination of findings of cam and pincer impingement. Arthroscopic treatment, consisting on femoral osteoplasty, labral repair, and microfractures of the chondral injury, was performed with good outcome. Page 18 of 61

Fig. 17: Adult hip displasia. Diagrams illustrate the two main subgroups of hip dysplasia: Type l: Hips in which the acetabulum is shallow, lies more vertical than normal, and has a radius of curvature greater than that of the femoral head. Such joints are incongruent and unstable. Hypertrophy of the labrum and capsule, labrum detached from the acetabular rim, ganglia or cysts around the hip joint within soft tissues are common findings on MR arthrography. Type II: Hips in which the acetabulum provides less than normal cover for the femoral head (short roof), and has a radius of curvature similar to that of the femoral head. These joints are congruent and essentially stable. However, the relative shortness of the acetabular roof reduces the area of the loaded surface which is then subject to increased pressure. Fatigue fracture and separation of a rim fragment, degenerative changes and labral tear, and associated intraosseus cysts in the acetabular roof which communicate with the joint are common findings on MR arthrography. Page 19 of 61

Fig. 18: Adult hip dysplasia in a 32 year-old woman. MR arthrography images show a femoral undercoverage (dysplasia type 2) with a complex tear of the antero-superior labrum and secondary paralabral cyst. Page 20 of 61

Fig. 19: Normal anatomy of the ligamentum teres. Diagrams illustrate the normal anatomy of the ligamentum teres.the ligamentum teres has a broad origin that blends with the entire transverse ligament of the acetabulum and is attached to the ischial and pubic sides of the acetabular notch by two bands. It inserts into the fovea capitis femoris, and its arterial supply is provided by the anterior branch of the posterior division of the obturator artery. Coronal MR arthrogram image shows the entire length of the ligamentum teres, from its origin in the transverse acetabular ligament to its insertion into the fovea capitis femoris, Axial MR arthrogram image shows the insertion of the ligamentum teres into the anterosuperior aspect of the fovea capitis femoris. Page 21 of 61

Fig. 20: Similarities between the ACL of the knee and ligamentum teres of the hip. The LT and ACL were found to show remarkable molecular homology, suggesting common functional properties. This finding provides experimental support for the proposed role of the LT as a hip joint stabiliser in humans. Page 22 of 61

Fig. 21: The hip is a very stable joint due to its osseous anatomy. Despite the intrinsic stability provided by the osseous anatomy, ligaments, capsule, labrum and musculotendinous structures surrounding the hip joint are important to give additional static and dynamic stability, particularly during rotation and extremes of motions associated with sporting activities. Page 23 of 61

Fig. 22: The capsuloligamentous complex is composed of circular and longitudinal fibers. The circular fibers, or zona orbicularis, are more substantive posterior and inferior and then blend into the deep iliofemoral ligament. The longitudinal fibers are reinforced by distinct bands, the capsular ligaments, the iliofemoral, pubofemoral, and ischiofemoral ligaments. Page 24 of 61

Fig. 23: On the left, we can see an example of traumatic dislocation in a rugby player. 3D CT image shows a large posterior wall fracture. On the right, a traumatic posterior dislocation in a professional soccer player. Axial fat-suppressed T1-weighted MR image shows a posterior labral tear and small acetabular lip fracture. Page 25 of 61

Fig. 24: Overuse instability in a 26-year old soccer player. AP diagram, coronal and axial MR arthrogram show a proximal tear of the IFL. Page 26 of 61

Fig. 25: 22-year old woman with generalized ligamentous laxity. Coronal and axial oblique MR arthrogram images show marked capsular redundancy. Page 27 of 61

Fig. 26: Iatrogenic instability, secondary to the arthroscopic treatment of cam type FAI. This patient had postsurgical anterior hip pain ans internal snapping syndrome. Note the postsurgical remodeling in the anterior head-neck interphase, the wide anterior capsulotomy with complete section of the iliofemoral ligament and anterior capsular redundancy. This is a subject of a considerable debate. Some arthroscopist perform a carefully capsular repair to avoid this kind of problems. Page 28 of 61

Fig. 27: Degenerative joint disease. Osteoarthritis of the hip (OA) commonly results from FAI and adult hip dysplasia. Hip arthroscopy outcomes in patients with Tönnis grade greater than 1 are poor. MR arthrography allows a precise evaluation of intraarticular injuries and better Tönnis staging than conventional plain films, with important implications in the treatment planning. Page 29 of 61

Findings and procedure details We review the main characteristic of articular injuries and the usefulness of the different classification systems in the different clinical entities such as femoroacetabular impingement (cam, pincer, and mixed types), adult hip dysplasia, ligamentum ters injuries, hip instability, and trauma based on MR arthrography findings with arthroscopic correlation in 184 patients. Images for this section: Fig. 28: Czerny`s classification of labral injuries is based on MR arthrogram findings. This classification is scarcely used on arthroscopic literature. This classification highlights the visualization or not of the recess between the joint capsule and the labrum with scarcely interest in the treatment planning. Page 30 of 61

Fig. 29: Lage s classification, which is the most commonly arthroscopic classification system used for hip labral tears. It is similar to the commonly used in meniscal injuries of the knee. Lage s system on MR arthrography has a poor correlation with arthroscopic findings. Page 31 of 61

Fig. 30: Mahorn (Multicenter Arthroscopy of the Hip Outcomes Research Network) classification system of labral lesions is simple and with excellent correlation between MR arthrography findings and arthroscopy. Page 32 of 61

Fig. 31: Partial chondro-labral separation in a patient with cam type FAI. Coronal MR arthrography image and arthroscopic correlation. Page 33 of 61

Fig. 32: Complete chondro-labral separation in a patient with cam type FAI. Coronal, sagittal, and axial MR arthrography images demonstrate complete chondro-labral detachment. Patient was treated with femoral osteochondroplasty, labral reattachment, and microfractures. Page 34 of 61

Fig. 33: Displaced complete chondro-labral separation in a patient with cam type FAI. Axial and sagittal MR arthrography images and arthroscopic correlation. Page 35 of 61

Fig. 34: Complex traumatic labral tear in a coronal MR arthrogram image with arthroscopic correlation. Page 36 of 61

Fig. 35: Degenerative tear of the antero-superior labrum in a patient with pincer type FAI. Sagittal and axial MR arthrography images and arthroscopic correlation. Page 37 of 61

Fig. 36: Hyperplastic labrum in a patient with adult hip dysplasia with degenerative labral tear. Coronal and axial MR arthrogram images. Page 38 of 61

Fig. 37: Coronal MR arthrogram image showing intrasubstancial changes on the medial side of the labrum. Arthroscopic image shows a labral bruising without tear. Commonly MR arthrography can not differentiate between the different types of intrasustancial changes (mucinoid, bruising, ossified, calcific). Page 39 of 61

Fig. 38: Coronal MR arthrogram and arthroscopic images reveal a floppy labrum (severely attenuated and frayed labrum). Page 40 of 61

Fig. 39: On the left, coronal MR arthrogram reveals an os acetabula in a patient with cam FAI. On the right, a polilobulated paralabral cyst in a patient with pincer FAI. Page 41 of 61

Fig. 40: MAHORN s classification of chondral injuries. Useful system to correlate MR arthrography and arthroscopic findings in chondral acetabular rim lesions. Page 42 of 61

Fig. 41: International cartilage repair society classification system. The most useful classification system for chondral injuries of acetabular non-rim, and femoral side injuries. Page 43 of 61

Fig. 42: Acetabular labral articular disruptions (ALAD) is a very useful system in the evaluation of rim injuries in patients with FAI. Page 44 of 61

Fig. 43: ALAD 1. Coronal and sagittal MR arthrogram, and arthroscopic images show cartilage softening with ondulate contour ("Wave sign"). The patient was treated arthroscopically with chondral debridement and microfracture procedure. Page 45 of 61

Fig. 44: ALAD 2. Coronal and sagittal MR arthrogram, and arthroscopic images show early peel back of the adjacent cartilage. Page 46 of 61

Fig. 45: ALAD 3. Consecutive MR arthrogram images in a patient with cam type FAI reveals chondral delamination. Arthroscopy confirms the chondral detachment (pocket lesion). Page 47 of 61

Fig. 46: ALAD 3. Coronal and sagital MR arthrogram images in a patient with hip dysplasia shows a massive chondral delamination. Page 48 of 61

Fig. 47: ALAD 3. Coronal and axial MR arthrogram images in a patient with complete rupture of the ligamentum teres, and secondary hip instability, show perifoveal chondral delamination (zone 6 of Ilizaliturri). The incidence of chondral injuries in the medial aspect of the femoral head (perifoveal) is increased in patients with LT injuries. Page 49 of 61

Fig. 48: The reporting of geographic location of labral and chondral injuries is facilitated with the geographic method (no rim lesions) and clock-face system (rim lesions). The clock-face system is a simply tool to locate labral and rim chondral injuries, where 6 o'clock was the transverse ligament and 3 o'clock was anterior in both sided. Ilizaliturri s method divides the acetabulum into 6 different zones based on the acetabular notch. The zones are the same for right- and left-side hips. The same method is applied for the femoral head. Page 50 of 61

Fig. 49: Gray and Vilar classification of LT injuries. Page 51 of 61

Fig. 50: Botser s classification of LT injuries. Page 52 of 61

Fig. 51: Coronal and axial MR arthrogram and arthroscopic images show degenerative changes of the LT without tear, and reactive focal synovitis. Page 53 of 61

Fig. 52: Coronal and axial MR arthrogram and arthroscopic image demonstrate a partial low-grade LT tear (<50%). Page 54 of 61

Fig. 53: Coronal and axial MR arthrogram and arthroscopic image demonstrate a partial low-grade LT tear (>50%). Page 55 of 61

Fig. 54: Coronal and axial MR arthrogram and arthroscopic image reveals a complete LT tear with secondary instabilty (increased articular distraction). Page 56 of 61

Fig. 55: Hip instability classification. Page 57 of 61

Fig. 56: Tönnis classification of osteoarthritis. It is the most commonly used in the arthroscopic literature. Initially radiographically based. However, MR arthrography allows a precise evaluation of intraarticular injuries, and adapted MR arthrography Tönnis classification is a useful tool in the preoperative evaluation of the hip joint. Page 58 of 61

Fig. 57: Tönnis OA stage 3. MR arthrography and arthroscopic images show severe OA (large subchondral cysts, severe narrowing of the joint space, and severe deformity of the femoral head. A Tönnis grade greater than 1, or a joint space of 2 mm or less are less likely to benefit from hip arthroscopy and more likely to require conversion to total hip arthroplasty/surface replacement arthroplasty. Page 59 of 61

Conclusion Uniformity in terms and classification system is essential for communication between radiologist and arthroscopic surgeons and allows accurate surgical planning. Unfortunately still there are too many systems and little consensus. The Multicenter Arthroscopy of the Hip Outcomes Research Network (Mahorn) classification provides a useful system for describing labral and chondral injuries with precise assessment of the types of lesions and its location within the hip joint. The ALAD classification (acetabular labral articular disruption) is useful in the evaluation of rim injuries in patients with FAI. Chondral injuries of the acetabular non-rim portion and of the femoral head should be assessed with the international society cartilage repair classification. The location of labral and chondral injuries is best described with the geographic method (no rim lesions) and clock-face system (rim lesions). Botser s classification system categorizes the ligamentum teres according to the size of the tear, and MR arthrography findings have a good correlation with arthroscopy. Normal 0 21 false false false ES-TRAD JA X-NONE Arthroscopic treatment of intraarticular injuries in patients with Tönnis grade greater than 1 of OA has poor outcomes; therefore MR arthrography should be used to help determining the type of treatment. Personal information Luis Cerezal Diagnóstico Médico Cantabria. Santander 39002 Spain lcerezal@gmail.com Page 60 of 61

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