Bone bruise in acute traumatic patellardislocation: volumetric magnetic resonance imaging analysis with follow-up mean of 12 months. 2012;40(4):837-844. They are best indicated in isolation in the setting of recurrent instability with minimal underlying osseous malalignment (normal TT-TG, minimal trochlear dysplasia). 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. Early detection particularly in the stage preceding the development of significant cartilaginous loss and osteoarthritis is critical. Seventeen patients with patellar retinacular ligament injuries were evaluated with magnetic resonance (MR) imaging. A ratio equal or more than 1.2 indicates patella alta [35] (Fig. 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. AJR Am J Roentgenol 1997; 168:117-122. At the time the article was last revised Joel Hng had 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]. (13a) A line is drawn between the cortex of the lateral trochlear facet on the most superior axial image showing cartilage. 5 a-d). 2). PubMedGoogle Scholar. 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. Evaluation of both of these soft tissue structures is critical when one examines a MRI following lateral patellar dislocation, as the extent of soft-tissue injury influences the use of operative repair. A bone bruise at the anterolateral aspect of the lateral femoral condyle is also apparent (arrowheads). However, patellofemoral tracking is a dynamic process with the spatial relationship between the articular surfaces varying depending on the position of the knee joint [57, 64]. b Trochlear dysplasia (9 inclination), Facet asymmetry assessment for trochlear dysplasia on axial MRI. Knee 10:215220, Terry GC, Hughston JC, Norwood LA (1986) The anatomy of the iliopatellar band and iliotibial tract. The medial patellar retinaculum and MPFL are best seen on MRI on the axial fluid-sensitive sequences. The injury typically occurs from a twisting event with the knee in mild flexion (less than 30). Cite this article. (5a) An axial T1-weighted image demonstrates the low blending fibers of the VMO and transverse MPFL at their attachment along the upper patella. A tear of the retinaculum is mostly seen after dislocation of the patella. volume10, Articlenumber:65 (2019) 2023 BioMed Central Ltd unless otherwise stated. Because of the transient and brief nature of lateral patellar dislocations, the diagnosis is frequently unrecognized by both patients and clinicians. (15a) A fat-suppressed proton density-weighted axial image at the level of the upper patella in the same patient demonstrates avulsion of the transverse band of the MPFL at the femoral attachment (arrow) with edema primarily anterior to the adductor magnus tendon (AM). 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. 8). Arthroscopy 23:305311, Kolowich PA, Paulos LE, Rosenberg TD, Farnsworth S (1990) Lateral release of the patella: indications and contraindications. Evaluate the TCO of your PACS download >, 750 Old Hickory Blvd, Suite 1-260Brentwood, TN 37027, Focus on Musculoskeletal and Neurological MRI, https://radsource.us/patella-alta-and-baja/, The Anterior Meniscofemoral Ligament of the Medial Meniscus. (Figs.1-A 1-A also and1-B). A tight lateral retinaculum can tilt the patella leading to increased pressure on the lateral facet causing pain (Ficat). The clinical evaluation can be more challenging in the absence of a dislocation history, and in this scenario, imaging can have a critical role. The distance from the tibial tubercle to the trochlear groove (TT-TG) provides a quantitative evaluation of excessive lateralization of the tibial tuberosity.7, (10a) Axial image of the knee with superimposition of the tibial tubercle from another slice (yellow outline). ADVERTISEMENT: Radiopaedia is free thanks to our supporters and advertisers. A generalized physical examination assessing ligamentous laxity and rotational profile of the lower extremity is critical. 1Department of Radiology, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, 149 Sangil-dong, Gangdong-gu, Seoul 134-727, Korea. LTI < 11 degrees indicates dysplasia. Distally, it attaches to the tibial tubercle via the patellar tendon. Usually, young individuals, particularly women, suffer the consequences of this disorder [2]. Despite the presence of numerous detailed anatomical dissection and MRI based studies of the anatomy2,3, there is much variability in the description of these structures within the literature. In eight of 17 patients, the mechanism of injury was a patellar tendon tear (n = 1) or valgus hyperextension (n = 7). In effect all three medial layers of the knee thus comprise the medial retinaculum, which is by itself not a discrete, single structure. Stress and shear forces that follow can result in cartilage damage and the development and evolution of osteoarthritis [57]. also supported our data in a magnetic resonance imaging (MRI) study of 82 patients with the diagnosis of lateral patella dislocation and found that 76% of medial retinacular/MPFL disruption occurred at its patellar insertion site, 49% occurred at the femoral attachment site, 30% showed injury of the MPFL at mid-substance, and 48% . 9 Lippacher S, Dejour S, Elsharkawi M, et al. Manage cookies/Do not sell my data we use in the preference centre. Elsevier, Philadelphia, Buckens CF, Saris DB (2010) Reconstruction of the medial patellofemoral ligament for treatment of patellofemoral instability: a systematic review. Additionally, in this degree of flexion, the quadriceps tendon itself engages the proximal trochlear groove and participates in force distribution [8,9,10]. AJR Am J Roentgenol 1997; 168:1493-1499. A 2015 Cochrane Review concluded that there is no significant increase in functional scores between nonoperative and operative management; however, surgical management does result in a significantly lower risk of recurrent dislocation at the cost of surgical complications [19]. 2010;30(4):961-81. The ensuing loss of medial restraint favors future patellar dislocations, especially if additional risk factors are present. Check for errors and try again. Incidence and concomitant chondral injuries in a consecutive cohort of primary traumatic patellar dislocations examined with sub-acute MRI. The main morphological features associated with patellar maltracking are trochlear dysplasia, lateralization of the tibial tuberosity, patella alta, and lateral patellar tilt. 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). 1 Lance E, Deutsch AL, Mink JH. AJR Am J Roentgenol. Nearly 50% of all first-time dislocators will sustain further dislocations. Jumping. 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. The MCL is composed of the superficial layer (layer 2 of the medial supporting structures) and the deep layer (layer 3 of the medial . J Bone Joint Surg Am 85-A:12381242, Article Patellar tracking refers to the dynamic relationship between the patella and trochlea during knee motion [1]. 2023 Apr;47(4):973-981. doi: 10.1007/s00264-023-05707-y. The lateral patellar retinaculum is a fibrous expansion comprising of superficial and deep layers. 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]. Facet asymmetry is determined by calculating the percentage of the medial to the lateral femoral facet length (Fig. The femoral attachment of the transverse band of the MPFL is not always discretely visible, and therefore secondary signs on MRI such as fluid, edema, and soft tissue thickening at the attachment indicate MPFL injury. 2023 Lineage Medical, Inc. All rights reserved, Knee & Sports | Lateral Patellar Compression Syndrome. Radiology 189:905907, Warren LF, Marshall JL (1979) The supporting structures and layers on the medial side of the knee: an anatomical analysis. Prior lateral patellar dislocation: MR imaging findings. 8600 Rockville Pike Although edema can be seen in other peripatellar fad pads on MRI, there is no clear association between patellar maltracking and prefemoral fat pad edema or with that at the suprapatellar fat pad [56]. Initial diagnosis is key to a successful outcome, as these injuries are easily overlooked on plain radiographs with poor results well documented from delayed management. Acta Orthop Belg 72:6571, Panagopoulos A, van Niekerk L, Triantafillopoulos IK (2008) MPFL reconstruction for recurrent patella dislocation: a new surgical technique and review of the literature. By using this website, you agree to our Sanders T, Paruchuri N, Zlatkin M. MRI of Osteochondral Defects of the Lateral Femoral Condyle: Incidence and Pattern of Injury After Transient Lateral Dislocation of the Patella. Orthopedic Surgery 22 years experience. https://doi.org/10.1186/s13244-019-0755-1, DOI: https://doi.org/10.1186/s13244-019-0755-1. Radiology 2000; 216: 582-585. Radiographics. 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. Epub 2023 Feb 7. HHS Vulnerability Disclosure, Help J Comput Assist Tomogr 2001; 25:957-962. Areas of scarring and osteochondral lesions become more common as the frequency of patellar dislocation increases. Lateral Patellar Dislocation. 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]. official website and that any information you provide is encrypted Lateral patellar dislocation refers to lateral displacement followed by dislocation of the patella due to disruptive changes to the medial patellar retinaculum. Osteochondral injuries to the inferomedial patella may be the result of impaction during dislocation or shearing with reduction. Predisposing factors to patellofemoral dislocation include patella alta, excessive lateral distance between the tibial tubercle and trochlear groove and a congenitally shallow trochlear groove5, any of which significantly increase a patients likelihood for dislocation. The above video demonstrates the mechanism of injury in patellar dislocation. The MPFL is also stripped from the femoral attachment (long arrow). sharing sensitive information, make sure youre on a federal lateral patellar retinacular sleeve, mak-ing this particular avulsion a rare oc-currence. Recurrent dislocations and chronic patellofemoral joint instability will lead to significant cartilage damage and severe arthritis if left untreated. (7a) A coronal T1-weighted image at the level of the patella demonstrates blending of fibers of the VMO with the MPFL superiorly. Inferiorly, components of the medial retinaculum blend with the patellar tendon. (19a) The corresponding STIR coronal image reveals the large displaced osteochondral fragment (arrow) at the lateral aspect of the lateral femoral condyle. Correspondence to Femoral osteochondral injuries, when present, typically involve the lateral weightbearing surface. Become a Gold Supporter and see no third-party ads. A buckle transducer was clamped on the lateral patellofemoral ligament and the transducer was calibrated to zero with the knee at full extension. Other indicated structures: gracilis (G), semitendinosus (ST), and adductor magnus (AM) tendons. 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). The lateral trochlear articular surface is usually more prominent than its medial portion. 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). 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 It is therefore helpful in surgical planning. Starok M, Lenchik L, Trudell D, Resnick D. Normal patellar retinaculum: MR and sonographic imaging with cadaveric correlation. Accessibility At the time the article was created Aditya Shetty had no recorded disclosures. 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. Federal government websites often end in .gov or .mil. This distance is the trochlear sulcus depth (TD). Lateral patellar tilt is a sensitive marker for patellar instability [45]. Patellar instability: Assessment on MR images by measuring the lateral trochlear inclination-initial experience. The patellar usually relocates, and the typical bone contusions are the key MRI features to diagnose transient lateral patellar dislocation (Fig. Knee Surg Sports Traumatol Arthrosc 14:235240, Article Google Scholar, Fithian DC, Paxton EW, Stone ML et al (2004) Epidemiology and natural history of acute patellar dislocation. 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. (14a) A fat-suppressed proton density-weighted coronal image following patellar dislocation reveals the classic lateral condylar bone bruise (arrow). The knee is a complex synovial joint that can be affected by a range of pathologies: Please Note: You can also scroll through stacks with your mouse wheel or the keyboard arrow keys. It runs obliquely and transversely and inserts on the patella and the patellar tendon, and is composed of two layers. 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. Reconstruction of the medial patellofemoral ligament for treatment of patellar instability. CT of both knees in 20 flexion demonstrating bilateral shallow trochlear groove (arrows) compatible with dysplasia and bilateral lateral patellar subluxation and lateral tilt. Radiology 1993; 189:905-907. In addition, symptomatic knees may demonstrate normal engagement between the patella and trochlea beyond 30 of flexion. Fluid extending into the VMO myotendinous junction is generally seen in the setting of coexisting MPFL/retinacular tears. Value of the tibial tuberosity-trochlear groove distance in patellar instability in the young athlete. 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. 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]. Another method is the CatonDeschamps index. 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. Lateral patellar compression syndrome is the improper tracking of the patella in the trochlear groove generally caused by a tight lateral retinaculum. The tight structures of the knee such as the lateral retinaculum need to be stretched and mobilized. {"url":"/signup-modal-props.json?lang=us"}, Moodaley P, Hng J, Hacking C, et al. Objective: Must rule out a tight iliotibial band (ITB) and weak quadriceps muscles (Juhn). Acute patellar dislocation (APD) is a common injury in children, accounting for up to 16% of acute knee hemarthroses. Bookshelf Insights into Imaging Treatment is nonoperative with physical therapy focusing on quadriceps stretching and strengthening. Medial patellar chondral injuries may occur during either the dislocation or reduction phases of injury. In the seven patients with hyperextension injuries, three had associated meniscal and cruciate ligament tears. 1-31. Analysis with magnetic resonance imaging. Infrapatellar (Hoffas) fat pad impingement is recognized as a cause of anterior knee pain. Concave impaction deformity of the inferomedial patella is a specific sign of prior LPD. Edema is also present medially in the region of the MPFL and medial retinaculum (arrowheads). J Orthop Sports Phys Ther 2017;47(10):815. doi:10.2519/ jospt.2017.6616 . Patella alta is related to a long patellar tendon and is considered a major factor associated with reduced contact area at the patellofemoral joint and a major contributor to patellar instability [33]. Medial retinacular complex injury in acute patellar dislocation: MR findings and surgical implications. Duke Radiology Case Review. The TT-TG index is the TTTG/TT-TE ratio [44]. 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. Magnetic Resonance Imaging Characteristics of the Medial Patellofemoral Ligament Lesion in Acute Lateral Patellar Dislocations Considering Trochlear Dysplasia, Patella Alta, and Tibial Tuberosity-Trochlear Groove Distance PubMed Lateral dislocation may also occur, less commonly, as the result of a direct blow to the medial aspect of the knee. Reconstruction of the MPFL has recently become an increasingly popular procedure for recurrent lateral patellar instability. On T2-weighted MR images, sprain is depicted as thickening of retinaculum with signal intensity signifying edema and hemorrhage (Fig. Crossref, Medline, Google Scholar; 32 Starok M, Lenchikl L, Trudell D, Resnick D. Normal patellar retinaculum: MR and sonographic imaging with cadaveric correlation. MRI and CT are superior modalities in looking for predisposing factors associated with patellar maltracking [26,27,28]. 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. It is therefore recommended that radiologists include measurement of TT-TG in reports on patients who undergo MRI for patellar instability. 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. 2012;40(4):837-844. As the knee progresses through greater flexion, the contact surface becomes more proximal on the patella. However, it lacks sensitivity with 40% of sizable osteochondral lesions being missed on initial presentation after patellar dislocation [16]. The https:// ensures that you are connecting to the (2011) ISBN: 9780781778602 -. 2012 Feb;41(2):137-48. doi: 10.1007/s00256-011-1291-3. 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. 23,29,37 The causative factors of . CAS For CT evaluation of the patellofemoral joint, patients are positioned supine, with mild external rotation of up to 15 with padding as needed to facilitate a relaxed state of the quadriceps musculature. Features that may predispose to patellar dislocation and/or patellar maltracking and can be evaluated with CT include patellar and trochlear morphology and the alignment between the two structures. Operative lateral retinaculum release is indicated in refractory cases. Acute traumatic instability most commonly occurs in young athletes in their second and third decade at an incidence rate of 29 per 100,000. Additionally, complex injuries to bone, cartilage, and ligaments may occur. AJR Am J Roentgenol 194:721727, Kalichman L, Zhang Y, Niu J et al (2007) The association between patellar alignment and patellofemoral joint osteoarthritis features--an MRI study.

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