Kirsch M, Fitzgerald S, Friedman H, Rogers L. Transient Lateral Patellar Dislocation: Diagnosis with MR Imaging. Google Scholar, Diederichs G, Issever AS, Scheffler S (2010) MR imaging of patellar instability: injury patterns and assessment of risk factors. Am J Sports Med 40:11191125, Boutris N, Delgado DA, Labis JS, McCulloch PC, Lintner DM, Harris JD (2018) Current evidence advocates use of a new pathologic tibial tubercle-posterior cruciate ligament distance threshold in patients with patellar instability. A trochlear depth of < 3mm indicates dysplasia. Our study focus was to evaluate medial patellofemoral ligament (MPFL) injury patterns and associated knee pathology using Magnetic Resonance Imaging studies. b Patellar alta evaluation using the CatonDeschamps index, which is the ratio between a line measured between the inferior margin of the patellar articular surface and the anterior aspect of the tibial plateau (black line) and the greatest length of the patellar articular surface (white line). The distance (double-headed arrow) from the deepest point of the trochlea (line B) to the middle of the tibial tubercle (line A) is measured, again by using the posterior plane of the condyles as the reference line (line C). a The posterior condylar line is drawn on the slice where the posterior femoral condyles are largest (dashed line). PubMed 25a) Axial proton density-weighted images at initial injury (left) and 5 months later demonstrate progression of medial retinacular and MPFL scarring (arrows) in this patient with trochlear dysplasia and chronic patellofemoral instability with a history of multiple prior dislocations. Edema is also present medially in the region of the MPFL and medial retinaculum (arrowheads). Clin Sports Med 21:521546 x, Article A Focal Defect at the Lateral Patellar Retinaculum on Clinical Knee MRI AJR Am J Roentgenol 161:109113, Lance E, Deutsch AL, Mink JH (1993) Prior lateral patellar dislocation: MR imaging findings. Division of Sports Trauma, Department of Orthopaedics, Aarhus University Hospital, Aarhus, Denmark. J Orthop Sports Phys Ther 2017;47(10):815. doi:10.2519/ jospt.2017.6616 . Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations. 9). The average annual incidence for patellar dislocation injuries ranged between 5.8 and 7.0 per 100,000 person-years in the civilian population, and up to 29 per 100,000 person-years in the 10-17 year age . Knee 13:266273. Less than 3-mm trochlear depth is indicative of trochlear dysplasia [24]. The VMO blends distally with the MPFL to attach to the medial border of the patella along its upper two thirds. Dejour et al. PDF Painful patellar swelling - dipot.ulb.ac.be The literature in this field has been extremely heterogeneous, and this has made clinical guidelines difficult to produce. The lateral retinaculum appears as a hyperechoic band originating from the iliotibial band and the vastus lateralis muscle. The patellar retinaculum and the MPFL are seen on MRI as well-defined low-signal-intensity bands. Kim et al. A typical bone bruise is seen within the anterolateral aspect of the lateral femoral condyle (asterisk). Methods: We compared 361 treated cases of aneurysm occlusion after subarachnoid hemorrhage from 1997 to 2003 with 281 cases from 2006 to 2014. The MCL is composed of the superficial layer (layer 2 of the medial supporting structures) and the deep layer (layer 3 of the medial . Burks RT, Desio SM, Bachus KN, Tyson L, Springer K. Spritzer CE, Courneya DL, Burk DL Jr, Garrett WE, Strong JA. Epidemiology Patellar dislocation accounts for ~3% of all knee injuries and is commonly seen in those individuals who participate in sports activities. (2a) In this case, it is the bone bruise within the anterolateral aspect of the lateral femoral condyle (long arrow) and the edema adjacent to the medial femoral condyle (arrowhead) that are the key to the diagnosis. Unable to process the form. Physical therapy is directed to increasing range of motion and to strengthening the VMO and quadriceps muscles. Orthopedic Surgery 22 years experience. Operative lateral retinaculum release is indicated in refractory cases. Terms and Conditions, Edema and thickening compatible with tears of the MPFL and medial retinaculum (red arrows) are apparent both anteriorly and posteriorly. A ratio > 1.3 indicates patella alta. Lastly, a sulcus-deepening procedure known as trochleoplasty may be indicated in the patient with significant trochlear dysplasia and recurrent instability. Transient lateral patellar dislocation. 1. The TT-TG distance can be influenced by the degree of knee flexion (reduces with flexion), and it is also smaller upon weight bearing [41]. MR findings were correlated with clinical, surgical, and arthroscopic findings. It has been shown that damage to the medial patellar stabilizers including medial patellar retinaculum and the medial patellofemoral ligament (MPFL) injuries are prevalent in 70100% of cases of lateral patellar dislocation [5, 27, 49,50,51]. AJR Am J Roentgenol 169:211215, Buchner M, Baudendistel B, Sabo D, Schmitt H (2005) Acute traumatic primary patellar dislocation: long-term results comparing conservative and surgical treatment. Anatomy of the lateral aspect of the knee is complex, with numerous structures providing stability. It is a major factor in patellar instability and was shown to be present in 85% of these patients [21]. It may occur without patellar lateralization. Long term follow up studies in patients who have undergone a lateral release have shown an increased incidence of patellofemoral arthritis. Additionally, MRs ability to delineate the extent of injury and predisposing factors is important in patient care and surgical planning. Patellar instability: Assessment on MR images by measuring the lateral trochlear inclination-initial experience. A Focal Defect at the Lateral Patellar Retinaculum on Clinical Knee MRI Twenty-six pelvic limbs were used for gross dissection, and four stifle regions from two animals were used for radiography and magnetic resonance imaging (MRI). These two structures blend with each other and are difficult to separate on imaging. A patient with acute first-time transient patellar dislocation without osteochondral lesions and severe risk factors for redislocation is generally treated conservatively. Radiology. HHS Vulnerability Disclosure, Help Early detection particularly in the stage preceding the development of significant cartilaginous loss and osteoarthritis is critical. Patellar tracking refers to the dynamic relationship between the patella and trochlea during knee motion [1]. Because of the transient and brief nature of lateral patellar dislocations, the diagnosis is frequently unrecognized by both patients and clinicians. Asymmetry of <40% suggests trochlear dysplasia [24]. Each of the mentioned assessment methods of patella alta has its own advantages and limitations. In effect all three medial layers of the knee thus comprise the medial retinaculum, which is by itself not a discrete, single structure. It is the angle between a line tangential to the subchondral bone of the posterior aspect of the femoral condyles and a line along the lateral trochlear facet. a Axial CT image demonstrating MPFL reconstruction (arrow heads). Lateral patellar dislocation is a common clinical entity with a characteristic MR appearance. Both knees are scanned simultaneously. Observer Agreement on the Dejour Trochlear Dysplasia Classification: A comparison of true lateral radiographs and axial magnetic resonance images. (8a) A more posterior coronal T1-weighted image also demonstrates the intimate relationship of the VMO and MPFL. Knee 10:215220, Terry GC, Hughston JC, Norwood LA (1986) The anatomy of the iliopatellar band and iliotibial tract. PFA is the angle between a line drawn along the bony lateral patellar facet and another line along the anterior aspect of the femoral condyles. (1a) A single fat-suppressed proton density-weighted coronal image is provided. Lateral patellar retinaculum. (6a) A more distal T1-weighted image reveals fibers of the oblique decussation of the MPFL which blend with the medial collateral ligament (MCL). The main morphological features associated with patellar maltracking are trochlear dysplasia, lateralization of the tibial tuberosity, patella alta, and lateral patellar tilt. 8 Lippacher S, Dejour S, Elsharkawi M, et al. Acute lateral patellar dislocation at MR imaging: injury patterns of Trochlear geometry, including slope of the lateral wall and depth, is an important factor. However, in the setting of osseous malalignment, MPFL reconstruction alone leads to higher rates of recurrent instability. Radiology 189:905907, Warren LF, Marshall JL (1979) The supporting structures and layers on the medial side of the knee: an anatomical analysis. Some controversy exists regarding whether female gender is a definite risk factor for patellar instability with certain studies identifying a 33% increased likelihood of first-time dislocation as well as three times high re-dislocation rates than males, whereas others have found roughly equal rates [2, 12,13,14]. The superficial layer originates from the lowest fibers of the iliotibial band and from an extension of vastus lateralis fascia. Clin J Sport Med 15:6266, Colvin AC, West RV (2008) Patellar instability. Disadvantages of CT compared to MRI include the use of ionizing radiation, which reduced soft tissue contrast resulting in limited evaluation of the cartilage, tendons, ligaments, muscles, and internal structures of the knee [64]. Bull NYU Hosp Jt Dis 67:2229, Dupuy DE, Hangen DH, Zachazewski JE, Boland AL, Palmer W (1997) Kinematic CT of the patellofemoral joint. To provide the highest quality clinical and technology services to customers and patients, in the spirit of continuous improvement and innovation. Acute lateral patellar dislocation at MR imaging: injury patterns of medial patellar soft-tissue restraints and osteochondral injuries of the inferomedial patella Injury to the medial retinaculum, MPFL, and VMO may be identified at MR imaging after acute LPD. Manage cookies/Do not sell my data we use in the preference centre. statement and Patellar maltracking: an update on the diagnosis and treatment strategies, https://doi.org/10.1186/s13244-019-0755-1, http://creativecommons.org/licenses/by/4.0/. Clin Biomech (Bristol, Avon) 19:10401047, Horton MG, Hall TL (1989) Quadriceps femoris muscle angle: normal values and relationships with gender and selected skeletal measures. Radiology 187:205212, Jibri Z, Martin D, Mansour R, Kamath S (2012) The association of infrapatellar fat pad oedema with patellar maltracking: a case-control study. Medial Collateral Ligament (MCL) and Medial Supporting - Radiology Key A tight lateral retinaculum can tilt the patella leading to increased pressure on the lateral facet causing pain (Ficat). a Axial PDFS right knee MR image at the level of the trochlear groove. Medial patellar. However, the use of this method is not widespread. The purpose of this article is to discuss the clinical and radiologic evaluation of patellar maltracking providing an update on the cross-sectional imaging assessment and also a synopsis of the management options. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. Peroneal Tendon Dislocation and Superior Peroneal Retinaculum Injury In order for the patella to engage with the femoral trochlea, a higher degree of flexion than normal is needed. In fact, most patellar maltracking occurs between extension and the first 30 of flexion. Int Orthop. California Privacy Statement, On the other hand, there are static MRI measurements that are routinely used as indicators of patellofemoral alignment during knee movement [30, 31]. In: West RV, Colvin AC (eds) The patellofemoral joint in the athlete. The discrimination between low-grade and high-grade dysplasia is important because prognosis and treatment may depend upon the severity of trochlear dysplasia. Immobilization Regime Following Lateral Patellar Dislocation: A Systematic Review and Meta-Analysis of the Current Evidence Base. 2010 Aug;36(4):353-60. doi: 10.1007/s00068-010-9165-2. Acta Orthop Scand 68:419423, Deie M, Ochi M, Sumen Y, Adachi N, Kobayashi K, Yasumoto M (2005) A long-term follow-up study after medial patellofemoral ligament reconstruction using the transferred semitendinosus tendon for patellar dislocation. This can provide a road map of developing a treatment strategy that would be primarily aimed at stabilizing the patellofemoral joint and halt the progression of cartilage loss. An increased tibial tubercletrochlear groove (TT-TG) indicates a lateralized tibial tuberosity, or a medialized trochlear groove [38]. Imaging of patellar fractures | Insights into Imaging | Full Text Macroscopic Anatomy of the Stifle Joint in the Pampa's Deer Another study noted an association between abnormal trochlear morphology and high-grade patellofemoral cartilage damage [58]. Traumatic lateral patellar dislocation is a common injury among young, athletic individuals and is generally transient in nature. A focused history of the mechanism, number, and circumstances of instability to date is essential. 2. Tibial Tubercle Osteotomy to Aid Exposure for Revision Total Knee Surgical management of patellar instability should be guided on an individual patient basis depending on history, physical examination, and radiologic findings as outlined above. The patella articulates with the trochlear groove of the anterior femur, which has corresponding lateral and medial patellar articular surfaces [6]. 0000293749 00000 n Injury 4:126130, 1972. Rethy Chhem, Etienne Cardinal. Lateral trochlear inclination is another quantitative method to diagnose trochlear dysplasia. sharing sensitive information, make sure youre on a federal The clinical evaluation can be more challenging in the absence of a dislocation history, and in this scenario, imaging can have a critical role. By using this website, you agree to our Abnormalities of the medial retinaculum and MPFL are seen in 82-100% of MRI examinations following patellar dislocation. It is a ratio between the patellar tendon length (along the inner surface of the tendon) and the diagonal patellar height [27]. Google Scholar, Nakagawa S, Kadoya Y, Kobayashi A, Tatsumi I, Nishida N, Yamano Y (2003) Kinematics of the patella in deep flexion. J Bone Joint Surg Br 87:3640, Wechter J, Macalena J, Arendt EA (1994) Lateral patella dislocations: history, physical exam, and imaging. The convex articular surface of the patella places it at risk for chondral injury in either the dislocation or the reduction phases of injury. In acute patellar dislocation, CT may demonstrate osseous impaction or fractures of the medial margin of the patella (with or without involvement of the articular surface) and/or the lateral surface of the lateral femoral condyle and intraarticular fragments. In acute traumatic lateral patellar dislocation, it is not only the patella that dislocates. Pediatric Lateral Patellar Retinacular Sleeve Avulsion - JOSPT Am J Sports Med 16:244249, Hawkins RJ, Bell RH, Anisette G (1986) Acute patellar dislocations. Despite non-operative management, recurrent patellar instability occurs in between 15 and 45% of patients [17,18,19,20]. 3.1 ). Clinical History: A 23 year-old female presents with medial knee pain following a twisting injury. The lateral patellar retinaculum is a fibrous expansion comprising of superficial and deep layers. (2011) ISBN: 9780781778602 -. These measurements are not routinely recorded in the MRI report, but in select situations may be helpful in quantifying low-grade versus high-grade dysplasia. Primary traumatic patellar dislocation | Journal of Orthopaedic Surgery Early diagnosis is essential, as chronic maltracking will lead to patellofemoral cartilage damage and osteoarthritis [3]. The authors would like to sincerely thank Cheryl Kreviazuk for all her efforts in the submission process. As is typical, a bone bruise extends anteriorly (arrowheads) from the site of the chondral defect. A newer method to assess for patella alta is the patellotrochlear index (PTI), which is measured in the midsagital MRI as the ratio of the length of trochlear cartilage engaged with the patella to the patellar cartilage length [36]. is a term coined for anatomic characteristics that lead to an increased Q angle and an exacerbation of patellofemoral dysplasia. Given the lack of history of direct trauma, a reliable diagnosis can be made. :: KJR :: Korean Journal of Radiology {"url":"/signup-modal-props.json?lang=us"}, Moodaley P, Hng J, Hacking C, et al. The degree of patellar tilt can be evaluated by measuring the patella tilt angle, which is the angle between the posterior condylar line and the maximal patella width line [47] (Fig. A buckle transducer was clamped on the lateral patellofemoral ligament and the transducer was calibrated to zero with the knee at full extension. A bone bruise of the lateral femoral condyle (asterisk) and an abnormally shallow trochlear groove (red line) are also indicated. 2010. [Nov;2019 . Patellofemoral friction syndrome: MRI findings of an - Eurorad The radiograph can be helpful in the acute presentation in detecting fractures in the setting of lateral (often transient) patellar dislocation. 2012;40(4):837-844. Medial patellofemoral ligament: cadaveric investigation of anatomy with MRI, MR arthrography, and histologic correlation. Femoral avulsion of the MPFL is a predictor of chronic instability and may be a surgical indication in some patients with acute injury. These are evaluated on most cranial axial image showing cartilage, approximately 3cm above the joint line. The lateral patellar retinaculum presents a superficial layer attached medially to the patella and patellar ligament, and extending laterally to the iliotibial band and vastus lateralis muscle fascia (Fig. 2012 Feb;41(2):137-48. doi: 10.1007/s00256-011-1291-3. Patellar maltracking occurs as a result of an imbalance in the dynamic relationship between the patella and trochlea. Are you sure you want to trigger topic in your Anconeus AI algorithm? Imaging plays a vital role in detecting not only the secondary damage but also subtle early features that can raise the suspicion for the presence of this entity. MRI Web Clinic, August 2010. https://radsource.us/patella-alta-and-baja/. The MCL is beneath the deep crural fascia (layer 1), from which it is separated by a variable amount of fat (Fig.
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