Are you sure you want to trigger topic in your Anconeus AI algorithm? Magn Reson Med Sci 17:195202, Elias DA, White LM (2004) Imaging of patellofemoral disorders. Although varied in presentation, successful management of all patients relies on thorough history taking, physical examination of the entire lower extremity, and appropriate imaging. Knee Surg Sports Traumatol Arthrosc 14:707712, Ahmad M, Janardhan S, Amerasekera S, Nightingale P, Ashraf T, Choudhary S (2019) Reliability of patellotrochlear index in patellar height assessment on MRI-correction for variation due to change in knee flexion. It is therefore helpful in surgical planning. Manage cookies/Do not sell my data we use in the preference centre. (1a) A single fat-suppressed proton density-weighted coronal image. 1 Pain is often described as medial because of soft tissue injuries that occur to the medial retinaculum and/or MPFL. Because the knee is flexed in dislocation, the patella impacts upon the weightbearing surface of the lateral femoral condyle. (24a) Scarring of the medial stabilizers (asterisk) often leads to healing in a more superior and lateral location (long arrow) leading to persistent medial instability, laxity and malalignment even after the patella has been repositioned. However, the patella starts to engage with the trochlea by 30 and is typically completely engaged by 45. 4). Less commonly, a direct laterally or medially orientated blow to the patella can precipitate dislocation. Am J Sports Med. HHS Vulnerability Disclosure, Help (4a) This 3D graphic view of the medial knee with the crural fascia and sartorius (S) muscle incised and reflected demonstrates the main medial contributors to patellar stability. Soft tissue procedures are designed to repair or tighten stretched and injured soft tissues contributing to patellar stability. As the knee progresses through greater flexion, the contact surface becomes more proximal on the patella. Subluxation and dislocation: recurrent. The lateral retinaculum appears as a hyperechoic band originating from the iliotibial band and the vastus lateralis muscle. Patellofemoral friction syndrome: MRI findings of an - Eurorad An official website of the United States government. This results in a slightly superolateral direction of pull on the patella by the quadriceps. By altering the insertion point of the patellar tendon, these procedures affect the timing and position of patellar engagement in the trochlea and have the ability to biomechanically offload damaged distal articular cartilage, thereby reducing pain and increasing stability simultaneously. Magnetic resonance imaging (MRI) is a vital tool in evaluating the potential cause(s) of anterior knee pain due to the complexity of the structure and biomechanics of the knee. As is typical, a bone bruise extends anteriorly (arrowheads) from the site of the chondral defect. 4). (19a) The corresponding STIR coronal image reveals the large displaced osteochondral fragment (arrow) at the lateral aspect of the lateral femoral condyle. Patellar maltracking occurs as a result of an imbalance in the dynamic relationship between the patella and trochlea. 1995 Jan;164(1):135-9. doi: 10.2214/ajr.164.1.7998526. 2012;40(4):837-844. 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 the seven patients with hyperextension injuries, three had associated meniscal and cruciate ligament tears. PubMed Skeletal Radiol 41:925931, Wittstein JR, Bartlett EC, Easterbrook J, Byrd JC (2006) Magnetic resonance imaging evaluation of patellofemoral malalignment. A patient with acute first-time transient patellar dislocation without osteochondral lesions and severe risk factors for redislocation is generally treated conservatively. Lateral Retinacular Release - Surgery Information On MRI, impingement is usually manifested as high signal intensity within the superolateral aspect of the infrapatellar fat pad on fluid-sensitive sequences (edema) (Fig. In our experience, injuries to the transverse band most often involve the femoral attachment, whereas injuries to the oblique decussation and associated medial retinacular structures are more common at the patellar attachment. Clin Orthop Relat Res 144:1626, Elias DA, White LM, Fithian DC (2002) Acute lateral patellar dislocation at MR imaging: injury patterns of medial patellar soft-tissue restraints and osteochondral injuries of the inferomedial patella. Knee 10:215220, Terry GC, Hughston JC, Norwood LA (1986) The anatomy of the iliopatellar band and iliotibial tract. MR imaging can help define patellar retinacular and associated osteochondral injuries, which may be clinically useful information. They are best indicated in isolation in the setting of recurrent instability with minimal underlying osseous malalignment (normal TT-TG, minimal trochlear dysplasia). volume10, Articlenumber:65 (2019) Lateral Patellar Compression Syndrome - Knee & Sports - Orthobullets 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. Patellar Fat Pad Abnormalities - Radsource The pages that follow contain general guidance on the diagnosis and treatment of chronic nontraumatic knee pain. Lastly, a sulcus-deepening procedure known as trochleoplasty may be indicated in the patient with significant trochlear dysplasia and recurrent instability. The joint line is scanned for lateral meniscal pathology, with varus stress applied as needed. PubMed However, subtle sprains are seen at the anterior medial retinaculum (arrowhead) and posterior MPFL (arrow) along with a large joint effusion. 28 Axial PDFS left knee MR image, demonstrating the method used for the measurement of trochlear depth. Trauma itself rarely causes patellofemoral dislocations without predisposing factors such as trochlear dysplasia, patella alta and lateralization of the tibial tuberosity. (22a) In this patient with an acute first time patellar dislocation injury, typical bone bruises were not apparent. the patellar retinaculum at the dynamic examination (Fig. PubMed 3). Osteochondral fractures are common in acute or recurrent transient lateral patellar dislocation, seen in up to 70% of cases. Patellar Tendon Tear - OrthoInfo - AAOS Lateral release and medial imbrication on their own are generally insufficient, but can be used to augment an MPFL repair or reconstruction or, if there is osseous misalignment, used in conjunction with a bony procedure particularly if there is recurrent instability or demonstrable lateral patellar tilt [73,74,75,76,77,78]. Open Orthop J 9:463474, Article A second line is drawn parallel to a line along the posterior femoral condyles. 21 Patellar dislocation not only has a high recurrence rate 51 but also readily causes articular cartilage damage, osteochondral fractures, and patellofemoral arthritis, which can ultimately lead to motor dysfunction and pain. This is the ratio between a line measured between the inferior margin of the patellar articular surface and the anterior aspect of the tibial plateau and the greatest length of the patellar articular surface. Objective: Must rule out a tight iliotibial band (ITB) and weak quadriceps muscles (Juhn). 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. Tibial tubercletrochlear groove distance (TT-TG) assessment. Insights Imaging 10, 65 (2019). 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]. An association has been demonstrated between patellofemoral cartilage damage and patellar maltracking. The objective of this paper was to describe the anatomy of the stifle joint (Articulatio genus) of the pampas deer (Ozotoceros bezoarticus, Linnaeus, 1758) by dissection and imaging studies. 2. 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). Prior lateral patellar dislocation: MR imaging findings. Kim et al. Arthroscopy 23:305311, Kolowich PA, Paulos LE, Rosenberg TD, Farnsworth S (1990) Lateral release of the patella: indications and contraindications. It is a major factor in patellar instability and was shown to be present in 85% of these patients [21]. Imaging assessment can start with the radiograph including anteroposterior and lateral views of the knee and skyline view of the patella. Depends on how bad: Small tears are observed and heal. Kamel S, Kanesa-Thasan R, Dave J et al. Lateral dislocation may also occur, less commonly, as the result of a direct blow to the medial aspect of the knee. What is the treatment for a patellar retinaculum tear? AJR Am J Roentgenol. MRI Web Clinic, August 2010. https://radsource.us/patella-alta-and-baja/. (3a) Graphical depictions of the mechanism of patellar dislocation: With the knee in flexion, the patella dislocated laterally. A commonly used one is the InsallSalvati ratio of patellar tendon length: patellar length. Observer Agreement on the Dejour Trochlear Dysplasia Classification: A comparison of true lateral radiographs and axial magnetic resonance images. (26a) An axial proton density-weighted image reveals trochlear dysplasia (line, indicating facet asymmetry and a shallow trochlear groove), ossification in the medial retinaculum and MPFL attachment anteriorly (short arrow) and diffuse scarring of the medial retinaculum (arrowheads)--these findings indicate chronic patellofemoral instability. (Figs.1-A 1-A also and1-B). Int Orthop 34:305309, Biedert RM, Albrecht S (2006) The patellotrochlear index: a new index for assessing patellar height. b Trochlear dysplasia (9 inclination), Facet asymmetry assessment for trochlear dysplasia on axial MRI. Patellar fractures are the most common cause of disruption of the extensor mechanism, six times as frequent as soft tissue injuries such as quadriceps or patellar tendon rupture [ 3 ]. 2012;40(4):837-844. 0000293749 00000 n Injury 4:126130, 1972. The MPFL plays a significant role in the stabilization of the medial aspect of the patella.Especially during the early stages of knee flexion, the MPFL is a critical component in patellar tracking and stability within the trochlear groove. Sports Med Arthrosc Rev 25:7277, Gillespie H (2012) Update on the management of patellar instability. As a common knee injury, patellar dislocation has a mean annual incidence of 5.8 in 100,000 people and is more prevalent in women. Given the lack of history of direct trauma, a reliable diagnosis can be made. 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. J Comput Assist Tomogr 2001; 25:957-962. Each of the mentioned assessment methods of patella alta has its own advantages and limitations. MR imaging of patellar retinacular ligament injuries - PubMed 1-B).Determine the possibility of a difficult knee revelation (following the medial parapatellar arthrotomy) owed to limited knee flexion, a lack of patellar mass, and patella baja when view on a lateral knee radiograph. Skeletal Radiol 48:387393, Schoettle PB, Zanetti M, Seifert B, Pfirrmann CW, Fucentese SF, Romero J (2006) The tibial tuberosity-trochlear groove distance; a comparative study between CT and MRI scanning. The incidence rates of primary patellar dislocation in a population-based setting among adults were revealed in some reports [ 3 - 5, 9 ]. AJR Am J Roentgenol 187:13321337, White BJ, Sherman OH (2009) Patellofemoral instability. The lateral retinaculum or lateral canthus is a complex integration of a number of structures. [Nov;2019 . MRI has been found to be 85%-92% sensitive for diagnosing MPFL injury (Seeley, 2013). The main morphological features associated with patellar maltracking are trochlear dysplasia, lateralization of the tibial tuberosity, patella alta, and lateral patellar tilt. 20,61 This is attributable to a medial retinacular injury, specifically, avulsion or tearing of the medial patellofemoral ligament. Eleven gave a history of recurrent patellar dislocation. Chronic fat impingement can result in chronic inflammation and fat pad hypertrophy. A sliver of fluid undermines a moderately thickened and scarred MPFL at the medial femoral condyle attachment consistent with a chronic partial stripping tear (arrowheads). Medial patellar. Trochlear depth of less than 3 mm on MRI has a sensitivity of 100% and a specificity of 96% for trochlear dysplasia.10. PubMed 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. The clinical evaluation can provide useful clues for the presence of such entity; however, the diagnosis can often be challenging especially in the absence of a documented history of patellar dislocation. PubMed Central J Bone Joint Surg Am Volume 90:27512762, Dixit S, Deu RS (2017) Nonoperative treatment of patellar instability. However, it lacks sensitivity with 40% of sizable osteochondral lesions being missed on initial presentation after patellar dislocation [16]. In type A, the trochlear preserves its concave shape but has shallow trochlear groove; type B is flattened or convex trochlea; in type C, the medial facet is hypoplastic (facet asymmetry) with high lateral facet, resulting in flattened joint surface in an oblique plane; and type D shows a cliff pattern with type C features and a vertical link between the medial and lateral facets. Deep lacerations are often associated with this type of injury. Femoral osteochondral injuries, when present, typically involve the lateral weightbearing surface. Created for people with ongoing healthcare needs but benefits everyone. Bone bruises at the anterolateral aspect of the lateral femoral condyle and at the inferomedial patella are the most constant findings in patients who have sustained a recent patellar dislocation. The radiograph can be helpful in the acute presentation in detecting fractures in the setting of lateral (often transient) patellar dislocation. Seventeen patients with patellar retinacular ligament injuries were evaluated with magnetic resonance (MR) imaging. Am J Sports Med 32:11141121, Tsavalas N, Katonis P, Karantanas AH (2012) Knee joint anterior malalignment and patellofemoral osteoarthritis: an MRI study. Ellas et al. 2). Clin Sports Med 21:521546 x, Article Reconstruction of the MPFL has recently become an increasingly popular procedure for recurrent lateral patellar instability. More recently, the TT-TG index was developed, which takes knee size into account by assessing the proximaldistal distance between the entrance of the chondral trochlear groove (TE) and the tibial tuberosity (TT). Become a Gold Supporter and see no third-party ads. Correspondingly, the patella must shift slightly medially during early flexion to engage the trochlear groove. 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. Imaging, particularly MRI, plays a vital role in the assessment of patellar maltracking. ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. Please enable it to take advantage of the complete set of features! In addition, symptomatic knees may demonstrate normal engagement between the patella and trochlea beyond 30 of flexion. Methods: We compared 361 treated cases of aneurysm occlusion after subarachnoid hemorrhage from 1997 to 2003 with 281 cases from 2006 to 2014. 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. Patella alta is considered an important factor in patellar instability. Gross anatomy The superficial layer originates from the lowest fibers of the iliotibial band and from an extension of vastus lateralis fascia. The patellar apprehension test is used to assess for lateral instability and is positive when pain or discomfort occurs with lateral translation of the patella. Several osteotomies have been described including the medializing ElmslieTrillat procedure, the anteromedializing Fulkerson osteotomy, and distalization osteotomy [87]. Because as noted above, the femoral bone bruise occurs as the patella moves forward during reduction, bone bruises at the lateral femoral condyle always course anteriorly from the site of any femoral chondral injury that may be present. However, the use of this method is not widespread. Acute Osteochondral Fractures in the Lower Extremities - Approach to Identification and Treatment. Less than 3-mm trochlear depth is indicative of trochlear dysplasia [24]. The lateral patellar retinaculum is a fibrous expansion comprising of superficial and deep layers. Before The above video demonstrates the mechanism of injury in patellar dislocation. Bone bruise in acute traumatic patellardislocation: volumetric magnetic resonance imaging analysis with follow-up mean of 12 months. Injury. The images should be scrutinized for the presence of chondral or osteochondral injury, especially if displaced as an intra-articular body, as this may affect surgical management. The most obvious presentation of patellar maltracking is that of the first time lateral patellar instability or recurrent instability thereafter. Between 15 and 45% of patients will develop recurrent patellar instability after acute dislocation, which is both functionally limiting and painful [17,18,19,20]. The knee is a complex joint with separate tibio-femoral and the patellofemoral articulations. It thickens as it inserts onto the lateral border of the patella, quadriceps tendon and patellar ligament. sharing sensitive information, make sure youre on a federal The deep layer of the lateral retinaculum contains thickenings that form ligaments providing stabilizing support to the patella. An imbalance of forces acting on the patellofemoral joint due to abnormal bony geometry or altered function of the active and passive soft tissue restraints may result in abnormalities of alignment and tracking of the patella. 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. Complete dislocation of the knee: spectrum of associated soft-tissue injuries depicted by MR imaging. Lateral patellar retinaculum | Radiology Reference Article A buckle transducer was clamped on the lateral patellofemoral ligament and the transducer was calibrated to zero with the knee at full extension. Knee CT images in the early post-operative period in a 19-year-old male with history of patellar maltracking. It was shown that certain features of patellar maltracking (increased sulcus angle, lateral patellar tilt, and a higher patellar tendon to patellar length ratio) are associated with cartilage loss and bone marrow lesions [59]. Elsevier, Philadelphia, Buckens CF, Saris DB (2010) Reconstruction of the medial patellofemoral ligament for treatment of patellofemoral instability: a systematic review. Radiographics. Burks RT, Desio SM, Bachus KN, Tyson L, Springer K. Spritzer CE, Courneya DL, Burk DL Jr, Garrett WE, Strong JA. 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. Knee Surg Sports Traumatol Arthrosc 22:26552661, Seitlinger G, Scheurecker G, Hgler R, Labey L, Innocenti B, Hofmann S (2012) Tibial tubercle-posterior cruciate ligament distance: a new measurement to define the position of the tibial tubercle in patients with patellar dislocation. b The patella tilt angle is measured between the posterior condylar line (dashed line) and the maximal patella width (solid line). Clinical History: A 23 year-old female presents with medial knee pain following a twisting injury. 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]. Flattening or developmental dysplasia of the trochlea leads to loss of normal patellar tracking and can predispose to lateral patellar dislocation with flexion. 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. The Medial Patellofemoral Ligament (MPFL) is an hour-glass shaped ligament made of bands of retinacular tissue. Radiology. The lateral patellar retinaculum is less commonly injured than the medial patellar retinaculum, however it is often disrupted during surgery to correct abnormal lateral patellar tracking or dislocation 3. Sports Med Arthrosc 15:6871, Longo UG, Rizzello G, Ciuffreda M et al (2016) Elmslie-Trillat, Maquet, Fulkerson, Roux Goldthwait, and other distal realignment procedures for the management of patellar dislocation: systematic review and quantitative synthesis of the literature. 7,14 While plain radiography is an important tool to diagnose APD, magnetic resonance imaging (MRI . Arthroscopy 22:643649, Carrillon Y, Abidi H, Dejour D, Fantino O, Moyen B, Tran-Minh VA (2000) Patellar instability: assessment on MR images by measuring the lateral trochlear inclination-initial experience. A perpendicular line is measured to the most posterior cortex of the central trochlea. Treatment is nonoperative with physical therapy focusing on quadriceps stretching and strengthening. Figure 1: ligaments (Gray's illustrations), View Pereshin Moodaley's current disclosures, see full revision history and disclosures, posterior suprapatellar (prefemoral or supratrochlear) fat pad, anterior suprapatellar (quadriceps) fat pad, accessory anterior inferior tibiofibular ligament, superficial posterior tibiotalar ligament, superficial posterior compartment of the leg (calf), accessory extensor digiti secundus muscle, descending branch of the lateral circumflex. 30 Correctly diagnosing APD can be difficult as the displaced patella usually relocates spontaneously, with fewer than 10% of patients presenting with fixed lateral dislocation. 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. Failure to identify or treat injury to the patellar retinaculum is associated with recurrent patellar instability and contributes to significant morbidity. At less than 30 of flexion, asymptomatic knees may demonstrate physiologic patellar tilt or subluxation. statement and The transverse stabilizers include the medial and lateral retinaculum, the vastus medialis and lateralis muscles, the ilio-tibial band, and the medial patellofemoral ligament (MPFL). Springer, New York, pp 1529, Cash JD, Hughston JC (1988) Treatment of acute patellar dislocation. The contralateral side may serve as an internal control or may also have anatomic factors predisposing to maltracking. MR findings were correlated with clinical, surgical, and arthroscopic findings. Fluid extending into the VMO myotendinous junction is generally seen in the setting of coexisting MPFL/retinacular tears. J Knee Surg 19:307316, Gonaives MB, Jnior LH, Soares LF, Gonaives TJ, Dos Santos RL, Pereira ML (2011) Medial patellofemoral ligament reconstruction to treat recurrent patellar dislocation. Surgical realignment procedures include medialization of the tibial tubercle particularly in patients with a TT-TG distance greater than 20mm. The .gov means its official. Early diagnosis is essential, as chronic maltracking will lead to patellofemoral cartilage damage and osteoarthritis [3]. Primary traumatic patellar dislocation | Journal of Orthopaedic Surgery Diagnosis is made clinically with pain with compression of the patella and moderate lateral facet tenderness and sunrise knee radiographs will often show patellar tilt in the lateral direction. 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. Because of the transient and brief nature of lateral patellar dislocations, the diagnosis is frequently unrecognized by both patients and clinicians. Medial Collateral Ligament (MCL) and Medial Supporting - Radiology Key A Focal Defect at the Lateral Patellar Retinaculum on Clinical Knee MRI Radiology 263:469474, Subhawong TK, Eng J, Carrino JA, Chhabra A (2010) Superolateral Hoffas fat pad edema: association with patellofemoral maltracking and impingement. The clinical evaluation can be more challenging in the absence of a dislocation history, and in this scenario, imaging can have a critical role. Patellar tilt assessment. The MCL is composed of the superficial layer (layer 2 of the medial supporting structures) and the deep layer (layer 3 of the medial . Magnetic Resonance Imaging Findings After Acute Patellar Dislocation in Patellar Dislocation (Acute) | Pediatric Orthopaedic Society of - POSNA Acute lateral patellar dislocation at MR imaging: injury patterns of medial patellar soft-tissue restraints and osteochondral injuries of the inferomedial patella. Jumping. Advantages of CT over plain radiography include its cross-sectional capability and ability to generate multiplanar reformations. Federal government websites often end in .gov or .mil. In effect all three medial layers of the knee thus comprise the medial retinaculum, which is by itself not a discrete, single structure. A tear of the reconstructed MPFL is indicated by fluid interrupting the fibers (27a, long arrow) (27b, arrowheads).
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