Radiology 225:736743, Kirsch MD, Fitzgerald SW, Friedman H, Rogers LF (1993) Transient lateral patellar dislocation: diagnosis with MR imaging. Edema is also present medially in the region of the MPFL and medial retinaculum (arrowheads). Sports Health 3:170174, Stensdotter AK, Hodges PW, Mellor R, Sundelin G, Hger-Ross C (2003) Quadriceps activation in closed and in open kinetic chain exercise. Reconstruction of the MPFL has recently become an increasingly popular procedure for recurrent lateral patellar instability. 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 . 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. This is an arthroscopic surgery ( a knee "scope" which is performed through 3 small incisions ( about inch each) around the knee. (3a) Graphical depictions of the mechanism of patellar dislocation: With the knee in flexion, the patella dislocated laterally. Knee 13:266273. Am J Sports Med 45:10121017, Pedersen ME, DaCambra MP, Jibri Z, Dhillon S, Jen H, Jomha NM (2015) Acute osteochondral fractures in the lower extremities - approach to identification and treatment. Tibial tubercletrochlear groove distance (TT-TG) assessment. Arthroscopy 35:537543, Mountney J, Senavongse W, Amis AA, Thomas NP (2005) Tensile strength of the medial patellofemoral ligament before and after repair or reconstruction. Given the lack of history of direct trauma, a reliable diagnosis can be made. J Bone Joint Surg Am 61:5662, Jerabek SA, Asnis PD, Bredella MA, Ouellette HA, Poon SK, Gill TJ 4th (2009) Medial patellar ossification after patellar instability: a radiographic finding indicative of prior patella subluxation/dislocation. 0000070933 00000 n 0000192215 00000 n 0000212094 00000 n The trochlea, due to its large surface area and concave contour, is rarely subject to chondral injury in patellar dislocation. Trochlear geometry, including slope of the lateral wall and depth, is an important factor. ity. Fractures may be caused either by excessive force through the extensor mechanism or by a direct blow. From 10 to 20 of flexion, the patella engages the trochlear groove with the contact area being the inferior most portion of the medial and lateral facets. On the other hand, the PTI is significantly altered with knee flexion [37]. The osteocartilaginous anatomy of the patellofemoral joint provides additional static stabilization to the joint. The close association of the MR with the MCL is also apparent. The common peroneal nerve can be localized in the popliteal fossa or identified posterior to the biceps femoris tendon and followed as it courses around the fibular neck. It should be noted that these procedures are mostly contraindicated in the patient with open physes due to growth arrest of the tibial tubercle apophysis. Distally, it attaches to the tibial tubercle via the patellar tendon. This results in a slightly superolateral direction of pull on the patella by the quadriceps. a Axial PDFS right knee MR image at the level of the trochlear groove. 2. Skeletal Radiol 30:484495, Tsujimoto K, Kurosaka M, Yoshiya S, Mizuno K (2000) Radiographic and computed tomographic analysis of the position of the tibial tubercle in recurrent dislocation and subluxation of the patella. Federal government websites often end in .gov or .mil. Complete disruption and avulsion are seen as discontinuity of ligament fibers with associated edema [50]. LTI < 11 degrees indicates dysplasia. Med Sci Sports Exerc 35:20432047, Steiner T, Parker RD (2009) Patella: subluxation and dislocation. Objective: The purpose of this study is to retrospectively investigate the frequency of a focal defect at the lateral patellar retinaculum on knee MRI and to determine the variables that are significantly associated with the defect. Bookshelf A perpendicular line is measured to the most posterior cortex of the central trochlea. Migliorini F, Marsilio E, Cuozzo F, Oliva F, Eschweiler J, Hildebrand F, Maffulli N. Life (Basel). Isacsson A, Olsson O, Englund M, Frobell RB. A generalized physical examination assessing ligamentous laxity and rotational profile of the lower extremity is critical. Additionally, MRs ability to delineate the extent of injury and predisposing factors is important in patient care and surgical planning. AJR Am J Roentgenol 179:11591166, Zhang GY, Zheng L, Ding HY, Li EM, Sun BS, Shi H (2015) Evaluation of medial patellofemoral ligament tears after acute lateral patellar dislocation: comparison of high-frequency ultrasound and MR. Eur Radiol 25:274281, Tecklenburg K, Dejour D, Hoser C, Fink C (2006) Bony and cartilaginous anatomy of the patellofemoral joint. The Insall-Salvati index is the most widely accepted measurement and is easily performed on radiographs and MRI examinations. From this insertion, it extends posteriorly to blend with the lateral margin of the knee capsule and inferior surface of the lateral tibial condyle 1,2. (17a) An axial T2 fat-suppressed image in another patient reveals a fluid filled gap (short arrow) at the site of attachment of the medial retinaculum. Medial patellofemoral ligament injury following acute transient dislocation of the patella: MR findings with surgical correlation in 14 patients. . Am J Sports Med 14:117120, Smith TO, Donell S, Song F, Hing CB (2015) Surgical versus non-surgical interventions for treating patellar dislocation. Because the knee is flexed in dislocation, the patella impacts upon the weightbearing surface of the lateral femoral condyle. Burks RT, Desio SM, Bachus KN, Tyson L, Springer K. Spritzer CE, Courneya DL, Burk DL Jr, Garrett WE, Strong JA. A patient with acute first-time transient patellar dislocation without osteochondral lesions and severe risk factors for redislocation is generally treated conservatively. Thus, imaging at positions both less than and greater than 30 can be used to avoid missing maltracking that might be captured at only certain degrees of flexion [64]. The VMO blends distally with the MPFL to attach to the medial border of the patella along its upper two thirds. At 0 extension, the patellar may lie completely above the level of the trochlea, without direct apposition between the two articular surfaces. FOIA Direct impact to the front of the knee from a fall or other blow is a common cause of tears. Gross anatomy The superficial layer originates from the lowest fibers of the iliotibial band and from an extension of vastus lateralis fascia. The anatomic relationship between the resultant force from the quadriceps and the line of pull of the patellar tendon is termed the Q angle and is normally 1015 of valgus [11]. 3). (9a) The Insall-Salvati Index is determined by dividing the length of the patellar tendon (PT) by the length of the patella (PL). Surgical management procedures can broadly be categorized as soft tissue procedures (lateral release, medial imbrication, and MPFL repair or reconstruction) and bony procedures (tibial tubercle transfer procedures and trochleoplasty). Rev Bras Ortop 46:160164, LeGrand AB, Greis PE, Dobbs RE, Burks RT (2007) MPFL reconstruction. Knee Surg Sports Traumatol Arthrosc 14:264272, McNally EG, Ostlere SJ, Pal C, Phillips A, Reid H, Dodd C (2000) Assessment of patellar maltracking using combined static and dynamic MRI. Medial patellar. 10 Diederichs G, Issever Ahi S, Scheffler S. MR Imaging of Patellar Instability: Injury Patterns and Assessment of Risk Factors. It is the percentage of the medial (a) to the lateral (b) trochlear facet length (a/b100%). Cookies policy. (11a) The depth of the trochlear groove is measured by drawing a line from the most anterior position of the medial trochlea to the lateral trochlear anterior cortex. Unable to load your collection due to an error, Unable to load your delegates due to an error. Created for people with ongoing healthcare needs but benefits everyone. As the knee joint ranges from extension to flexion, the articular surface area of the patella is in contact with the femur changes. Orthopedic Surgery 22 years experience. Int Orthop 34:311316, Donell ST, Joseph G, Hing CB, Marshall TJ (2006) Modified Dejour trochleoplasty for severe dysplasia: operative technique and early clinical results. The lateral patellar retinaculum is a fibrous expansion comprising of superficial and deep layers. 5. Eur Radiol 22:418428, Sonin AH, Pensy RA, Mulligan ME, Hatem S (2002) Grading articular cartilage of the knee using fast spin-echo proton density-weighted MR imaging without fat suppression. Kamel S, Kanesa-Thasan R, Dave J et al. 2023 BioMed Central Ltd unless otherwise stated. Patellar dislocation most commonly results from a twisting motion, with the knee in flexion and the femur rotating internally on a fixed foot (valgus-flexion-external rotation) 1. 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). It acts as a powerful extensor of the knee. There are several different techniques described in the literature to assess patella alta and many of these are reviewed in detail in the MRI Web Clinic, August 20106. Zaid Jibri. 2011;39(8):1756-1761. AJR Am J Roentgenol. Surgical realignment procedures include medialization of the tibial tubercle particularly in patients with a TT-TG distance greater than 20mm. Frequently underdiagnosed, the patellofemoral friction syndrome, also called Hoffa's fat cushion compression syndrome, is mainly represented by 2 characteristic symptoms, which are mainly found in women (especially if they present obesity or rapid weight gain, as in pregnancy): patellofemoral pain and instability in the patellar . In full extension, the patella has little to no contact with the trochlear groove and, therefore, is in a position of higher risk for instability. Alimorad Farshchian M. D.. Farshchian's Orthopedic Regenerative Series. 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]. 9). The conditions are presented anatomicallyanterior, lateral, medial, or posteriorwith common etiologies, history and physical exam findings, and diagnosis and treatment options for each (see Table, page 28). Because of the transient and brief nature of lateral patellar dislocations, the diagnosis is frequently unrecognized by both patients and clinicians.1 Pain is often described as medial because of soft tissue injuries that occur to the medial retinaculum and/or MPFL. A tight lateral retinaculum can tilt the patella leading to increased pressure on the lateral facet causing pain (Ficat). Lateral patellar retinaculum. Anyone you share the following link with will be able to read this content: Sorry, a shareable link is not currently available for this article. Elsevier, Philadelphia, Buckens CF, Saris DB (2010) Reconstruction of the medial patellofemoral ligament for treatment of patellofemoral instability: a systematic review. These two structures blend with each other and are difficult to separate on imaging. Stretching exercises for Patellofemoral pain. However, it lacks sensitivity with 40% of sizable osteochondral lesions being missed on initial presentation after patellar dislocation [16]. A commonly used one is the InsallSalvati ratio of patellar tendon length: patellar length. In eight of 17 patients, the mechanism of injury was a patellar tendon tear (n = 1) or valgus hyperextension (n = 7). Int J Sports Med 29:359365, Smith TO, Walker J, Russell N (2007) Outcomes of medial patellofemoral ligament reconstruction for patellar instability: a systematic review. lateral patellar retinaculum tear or invasion. A facet ratio of < 40% indicates dysplasia. These parameters can be evaluated using dynamic MRI [29]. Springer Nature. Current Concepts Regarding Patellofemoral Trochlear Dysplasia. Surgical indications following patellar dislocation include the presence of a chondral or osteochondral body, significant rupture of the medial stabilizers most importantly the MPFL, a persistent laterally subluxed patella, or a second dislocation injury in a patient with malalignment or dysplasia. AJR Am J Roentgenol 1997; 168:1493-1499. The patella itself is shaped as an inverted triangle and is embedded in the quadriceps tendon, making it the largest sesamoid bone in the body [6]. Traumatic lateral patellar dislocation is a common injury among young, athletic individuals and is generally transient in nature. 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. Osteochondral injuries of the inferomedial patella are seen in up to 70% of patellofemoral dislocations. The MPFL is attached to the region of the adductor tubercle or medial femoral epicondyle extending deep to the vastus medialis obliquus (VMO) and attaching to the superior two thirds of the patella [52]. Prior lateral patellar dislocation: MR imaging findings. Terms and Conditions, Magnetic Resonance Cholangiopancreatography MRI PREMIUM Digestive system Illustrations PREMIUM CT axial male abdomen and pelvis CT PREMIUM CT peritoneal cavity CT PREMIUM MRI female pelvis MRI PREMIUM Female pelvis Eur J Trauma Emerg Surg. Courtesy of Daniel Bodor, MD, Radsource. PubMed Levy B, Tanaka M, Fulkerson J. 6 Cone R. Patella Alta and Baja. J Bone Joint Surg Br 87:3640, Wechter J, Macalena J, Arendt EA (1994) Lateral patella dislocations: history, physical exam, and imaging. Patellar dislocation accounts for ~3% of all knee injuries and is commonly seen in those individuals who participate in sports activities. Normal = 0.8 to 1.2. Both knees are scanned simultaneously. Am J Sports Med. The purpose of this article is to discuss the evaluation of patellar maltracking providing an update on the imaging assessment and also a synopsis on the management options. The trochlear depth is calculated by measuring the mean of the maximum anteroposterior (AP) distance of the medial and lateral femoral condyles minus the distance between the deepest point of the trochlear groove and the line paralleling the posterior femoral condyles surfaces (Fig. With knee extension and subsequent reduction, the patella bounces back into position and in doing so, the medial patella impacts against the non-weightbearing anterolateral aspect of the lateral femoral condyle, resulting in the characteristic marrow edema pattern. 1. Lateral patellar dislocation refers to lateral displacement followed by dislocation of the patella due to disruptive changes to the medial patellar retinaculum. (Figs.1-A 1-A also and1-B). At less than 30 of flexion, asymptomatic knees may demonstrate physiologic patellar tilt or subluxation. 4). Sports Med Arthrosc 15:5760, Nam EK, Karzel RP (2005) Mini-open medial reefing and arthroscopic lateral release for the treatment of recurrent patellar dislocation: a medium-term follow-up. The medial patellar retinaculum is part of the anterior third of the medial joint capsule. A bone bruise occurs anterior to this site of impaction as the patella reduces with knee extension. Medial retinacular complex injury in acute patellar dislocation: MR findings and surgical implications. It is a recognized cause of anterior pain and in extreme cases presents as acute and often recurrent patellar dislocation, which is usually transient. Imaging assessment can start with the radiograph including anteroposterior and lateral views of the knee and skyline view of the patella. 2. The patients are then J-braced for 3 to 6 months for all sports activities. It is composed of Lockwood's ligament (inferior suspensory ligament), the lateral extension or horn of the levator aponeurosis, the continuations of the pretarsal and preseptal muscles, and the check ligament of the lateral rectus muscle. 2010;30(4):961-81. The normal trochlea is concave with medial and lateral facets articulating with the patellar facets. statement and The tight structures of the knee such as the lateral retinaculum need to be stretched and mobilized. Epidemiology Patellar dislocation accounts for ~3% of all knee injuries and is commonly seen in those individuals who participate in sports activities. Yu JS, Goodwin D, Salonen D, Pathria MN, Resnick D, Dardani M, Schweitzer M. AJR Am J Roentgenol. Various parameters can be used in assessing and predicting the presence of patellar maltracking. 2012;40(4):837-844. The goal of patellar instability treatment is to achieve a stable, functional, and pain-free knee and ultimately to halt or slow the development of osteoarthritis. (27a) Axial and (27b) coronal fat suppressed proton density-weighted images in a patient who experienced recurrent patellar dislocation following surgery. Reference article, Radiopaedia.org (Accessed on 02 May 2023) https://doi.org/10.53347/rID-27273, {"containerId":"expandableQuestionsContainer","displayRelatedArticles":true,"displayNextQuestion":true,"displaySkipQuestion":true,"articleId":27273,"questionManager":null,"mcqUrl":"https://radiopaedia.org/articles/lateral-patellar-dislocation/questions/2391?lang=us"}, Case 14: transient lateral patellar dislocation, see full revision history and disclosures, anterior cruciate ligament avulsion fracture, posterior cruciate ligament avulsion fracture, Ahlback classification system in assessing osteoarthritis of the knee joint, Kellgren and Lawrence system for classification of osteoarthritis, anterior cruciate ligament mucoid degeneration, MRI grading system for meniscal signal intensity, medial retinacular abnormalities (ranging from strain to complete disruption) with adjacent periligamentous edema and hemorrhage, lateral displacement of patella (not necessarily seen in transient dislocation), medial patellar contusion +/- corresponding lateral femoral condyle contusion, direct trauma to lateral knee:normally no patellar contusion. Several methods have been used to assess patella alta. 2010 Aug;36(4):353-60. doi: 10.1007/s00068-010-9165-2. This allows for greater detailed evaluation of the patellar and trochlear morphology, patellofemoral relationship, and status of the joint. In effect all three medial layers of the knee thus comprise the medial retinaculum, which is by itself not a discrete, single structure. Intervention: Taping the knee to promote medial glide . Nonoperative treatment is generally recommended in first time dislocators unless there are MRI findings of severe predisposing dysplasia and the presence of a chondral or osteochondral body. Traumatic dislocations are commonly associated with other injuries including that of the MPFL, meniscal pathology, and osteochondral fractures of the femur or patella [15, 16]. Note the edema in the superolateral aspect of Hoffas fat pad (arrow). This can provide a road map for formulating a treatment strategy that would be primarily aimed at stabilizing the patellofemoral joint to halt or slow the progression of articular cartilage loss. Oper Tech Sports Med 6:247258, Dejour H, Walch G, Nove-Josserand L, Guier C (1994) Factors of patellar instability: an anatomic radiographic study. Unable to process the form. Recurrent dislocations and chronic patellofemoral joint instability will lead to significant cartilage damage and severe arthritis if left untreated. A ratio equal or more than 1.2 indicates patella alta [35] (Fig. Imaging, particularly MRI, can detect subtle features that could lead to the diagnosis, probably even more importantly when there is no clear history of patellar dislocation or before its development. Please enable it to take advantage of the complete set of features! a Sagittal PD knee MRI showing the method of assessing the InsallSalvati index, calculated as the ratio of the patellar tendon length at its inner aspect (white dashed line) to the greatest diagonal length of the patella (white line). The posterior articulating surface of the patella is composed of two facets, a medial and lateral facet, separated by a vertical ridge, and in 30% of the population, there is a third facet, the odd facet, most medially. 3.1 ). Disclaimer. Observer Agreement on the Dejour Trochlear Dysplasia Classification: A comparison of true lateral radiographs and axial magnetic resonance images. An increased tibial tubercletrochlear groove (TT-TG) indicates a lateralized tibial tuberosity, or a medialized trochlear groove [38]. In addition, symptomatic knees may demonstrate normal engagement between the patella and trochlea beyond 30 of flexion. Thus, to assess for maltracking specifically, a multi-stage CT with a variable number of repeated acquisitions at variable degrees of flexion can also be performed [57]. The TT-TG is evaluated by measuring the distance between the most anterior point of the tibial tuberosity and the deepest point of the trochlear groove using two lines drawn perpendicular to the tangent to the posterior borders of the femoral condyles [31] (Fig. The decreased patellar contact area decreases stability particularly in shallow degrees of flexion and thus predisposes to lateral patellar subluxation. 4). Additionally, return to sport can be as low as 45%, leaving many patients searching for further management options [12]. A tear of the retinaculum is mostly seen after dislocation of the patella. Transient lateral patellar dislocation. 8600 Rockville Pike PMID: 9168713. In the setting of osseous patellar malalignment, an osseous procedure such as tibial tubercle transfer osteotomy can be performed (Fig. Quinn described the MRI findings following acute patellar dislocation as contusion or impaction of the medial patellar facet and lateral femoral condyle, along with injury of the medial retinaculum and/or medial patellofemoral ligament (MPFL) (Quinn, 1993). In patients without osseous malalignment, MPFL reconstruction and plication of the medial restraints is reported to decrease re-dislocation rates to 5%. Over 100 different procedures have been described for the treatment of patellar instability, and this reflects the various causes for instability and lack of current gold standard [66, 69, 72]. The MPFL is composed of a stronger transverse band and a more variable and weaker oblique decussation. Adjunctive treatments such as knee aspiration and patellar stabilizing braces have been proposed to decrease swelling and enable early range of motion; however, there is no conclusive evidence for their use [71]. Eur Radiol 10:10511055, Stefanik JJ, Zumwalt AC, Segal NA, Lynch JA, Powers CM (2013) Association between measures of patella height, morphologic features of the trochlea, and patellofemoral joint alignment: the MOST study. The mechanism is commonly a non-contact twisting injury of the lower extremity with the knee extended and external rotation of the foot and is perceived as the knee giving way. The patella will often self-reduce by reflexic contraction of the quadriceps muscles. This protocol can help in evaluating for osseous integrity, morphology, and patellofemoral alignment [63] (Fig. Inferiorly, components of the medial retinaculum blend with the patellar tendon. A study has found that the femoral groove tends to be shallower in osteoarthritis patients compared to those with normal cartilage, regardless of age. b Trochlear dysplasia (9 inclination), Facet asymmetry assessment for trochlear dysplasia on axial MRI. Patellar tendon lateral femoral condyle friction syndrome is one of several entities that result in anterior knee pain and in which abnormalities of the patellar fat pads are found on MR imaging. The knee is a complex joint with separate tibio-femoral and the patellofemoral articulations. Patella instability in children and adolescents. All authors (ZJ, PJ, KSR, MLS, GD) contributed to the study design, drafted the work, and revised it critically for final submission. 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 subchondral bone (Fig. Subluxation and dislocation: recurrent. Radiographics 30:961981, Tscholl PM, Wanivenhaus F, Fucentese SF (2017) Conventional radiographs and magnetic resonance imaging for the analysis of trochlear dysplasia: the influence of selected levels on magnetic resonance imaging. It is a geometric abnormality of the trochlear groove that affects its shape and depth mainly at its superior part, which can result in abnormal tracking of the patella along the trochlea. Anatomically, the transverse band of the MPFL is also a component of the medial retinaculum, but for purposes of MRI interpretation, the general convention is to describe abnormalities of the transverse band as being MPFL injuries, whereas more distal injuries which involve multiple layers are generally referred to as abnormalities of the medial retinaculum. 1835 31 - 40 27 30.0 41 - 50 22 24.4 50 + 4 4.4 Total 90 100.0 Age Distribution Number Percent Sex Female 19 21.1 Male 71 78.9 Materials and methods: Two radiologists independently reviewed 99 knee MR images for the presence of a focal defect at the lateral patellar retinaculum and . Acute patellar dislocation (APD) is a common injury in children, accounting for up to 16% of acute knee hemarthroses. no financial relationships to ineligible companies to disclose. In these patients, a triad of findings that included focal impaction injuries involving the lateral femoral condyle, osteochondral injuries of the medial patellar facet, and injuries of the medial retinacular ligament were seen. Hemarthrosis is rare in lateral patellar sleeve fractures, as the lateral pole is not as vascularized as the inferior pole of the patella that has the most important blood supply of patella [5 ]. Am J Sports Med 28:472479, Lewallen L, McIntosh A, Dahm D (2015) First-time patellofemoral dislocation: risk factors for recurrent instability. 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. TT-TG distance of more than 20mm is believed to be nearly always associated with patellar instability [27]. The most accepted indication for surgical management of patellar instability is the presence of a large displaced osteochondral fracture or loose body. Specialists of neuroradiology and vascular neurosurgery decided over the modality assignment. Correspondingly, the patella must shift slightly medially during early flexion to engage the trochlear groove. AJR Am J Roentgenol.
Europa League Referee Appointments, King Piece Fruits Wiki, 2023 Nfl Draft Defensive Tackles, Do Corgis Shed More Than Labs, Pony Town Skin Color Codes, Articles L