Check for errors and try again. 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 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. (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 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. These prevailing anatomic indices feature prominently into the probability of recurrence, and understanding their variability and pathophysiology is critical to successful management of these patients. Pedersen ME, DaCambra MP, Jibri Z, Dhillon S, Jen H, Jomha NM. They include: pain with compression of patella and moderate lateral facet tenderness, inability to evert the lateral edge of the patella, mainstay of treatment and should be done for extensive period of time, closed chain short arc quadriceps exercises, pain refractory to extensive rehabilitation, ideal candidate has no symptoms of instability, medial patellar glide of less than one quadrant, lateral patellar glide of less than three quadrants, only elevate 1 cm or else risk of skin necrosis, indicated only for instability with lateral translation (not isolated lateral tilt), viewing through superior portal will show medial facet does not articulate with trochlea at 40 degrees of knee flexion, postoperatively the patella should be able to be, patellar instability with medial translation, Spontaneous Osteonecrosis of the Knee (SONK), Osgood Schlatter's Disease (Tibial Tubercle Apophysitis), Anterior Superior Iliac Spine (ASIS) Avulsion, Anterior Inferior Iliac Spine Avulsion (AIIS), Proximal Tibiofibular Joint Ganglion Cysts, Pre-Participation Physical Exam in Athlete, Concussions (Mild Traumatic Brain Injury). Objective: This prospective study is designed to detect changes in the treatment of ruptured intracranial aneurysms over a period of 17 years. From the inside of the knee the lateral retinaculum is incised, from the inside, allowing the kneecap to untilit itself. 4). Early detection particularly in the stage preceding the development of significant cartilaginous loss and osteoarthritis is critical. Seven of the nine patients with patellar dislocation injuries had frank osteochondral injuries. 1997 Jun;168(6):1493-9. doi: 10.2214/ajr.168.6.9168713. Cite this article. 3). The marrow edema and medial patellofemoral ligament (MPFL) injury pattern above are virtually pathognomonic of a transient lateral patellar dislocation, as little else will cause such an appearance. Each of the mentioned assessment methods of patella alta has its own advantages and limitations. Curr Rev Musculoskelet Med 11:253260, Article 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. 1Department of Radiology, Kyung Hee University Hospital at Gangdong, Kyung Hee University School of Medicine, 149 Sangil-dong, Gangdong-gu, Seoul 134-727, Korea. Deep lacerations are often associated with this type of injury. The trochlear groove and patella may have abnormal morphology that predisposes to patellar dislocation. Complete disruption and avulsion are seen as discontinuity of ligament fibers with associated edema [50]. MRI Web Clinic, August 2010. https://radsource.us/patella-alta-and-baja/. [Google Scholar] 6. Trochlear depth=[(a+b)/2]c, Lateral trochlear inclination measurement on axial MRI. Part of Various parameters can be used in assessing and predicting the presence of patellar maltracking. Patellar tilt can also be assessed using the patellofemoral angle (PFA). 1). The main morphological features associated with patellar maltracking are trochlear dysplasia, lateralization of the tibial tuberosity, patella alta, and lateral patellar tilt. It can be divided into nonoperative and operative management. lateral patellar retinaculum tear or invasion. AJR Am J Roentgenol. On T2-weighted MR images, sprain is depicted as thickening of retinaculum with signal intensity signifying edema and hemorrhage (Fig. It is a major factor in patellar instability and was shown to be present in 85% of these patients [21]. It is measured at the mid-point of the patella on the axial slices [48]. 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. The trochlea, due to its large surface area and concave contour, is rarely subject to chondral injury in patellar dislocation. 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. 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. The VMO is active, not only in full extension but also at 30 degrees and up to 100 degrees of flexion. The incidence rates of primary patellar dislocation in a population-based setting among adults were revealed in some reports [ 3 - 5, 9 ]. Medial patellar. (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. In the seven patients with hyperextension injuries, three had associated meniscal and cruciate ligament tears. Similar 2-year results in 125 randomized patients. TT-TG distance of more than 20mm is believed to be nearly always associated with patellar instability [27]. Magn Reson Med Sci 17:195202, Elias DA, White LM (2004) Imaging of patellofemoral disorders. 1995 Jan;164(1):135-9. doi: 10.2214/ajr.164.1.7998526. official website and that any information you provide is encrypted 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. The medial patellar retinaculum (MPR) and the lateral patellar retinaculum (LPR) are vital structures for the stability of the patella. 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. Knee 10:215220, Terry GC, Hughston JC, Norwood LA (1986) The anatomy of the iliopatellar band and iliotibial tract. Both MRI and ultrasound are accurate imaging modalities in the detection of MPFL injuries [5, 50, 51]. 5). The adductor magnus tendon (AT) attaches to the adductor tubercle, which lies posterior and superior to the femoral attachment of the MPFL. Insights into Imaging The tight structures of the knee such as the lateral retinaculum need to be stretched and mobilized. Osteochondral fractures are common in acute or recurrent transient lateral patellar dislocation, seen in up to 70% of cases. 4). MRI and CT are superior modalities in looking for predisposing factors associated with patellar maltracking [26,27,28]. 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. The medial patellar retinaculum is part of the anterior third of the medial joint capsule. Chronic fat impingement can result in chronic inflammation and fat pad hypertrophy. 5. The authors declare that they have no competing interests. ity. FOIA Post WR, Teitge R, Amis A (2002) Patellofemoral malalignment: looking beyond the viewbox. The transverse band attaches to the upper pole of the patella, and this component originates on a bony groove that lies between the adductor tubercle and the medial epicondyle, slightly posterior to the epicondyle. 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. Persistent abnormalities of patellar alignment and abnormalities of trochlear morphology are also common, and should be carefully described. PubMedGoogle Scholar. 2023 Lineage Medical, Inc. All rights reserved, Knee & Sports | Lateral Patellar Compression Syndrome. Patellar instability: Assessment on MR images by measuring the lateral trochlear inclination-initial experience. 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. Most, however, agree regarding the importance of the MPFL and its role as the strongest restraint to lateral patellar displacement. The MPFL is also stripped from the femoral attachment (long arrow). A small osseous avulsion (arrowhead) is seen in this region. Jumping. 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]. In a series of 474 patients with anterior knee pain, patellar tilt or subluxation was present in 40% of the cases on axial MRI [46]. Observer Agreement on the Dejour Trochlear Dysplasia Classification: A comparison of true lateral radiographs and axial magnetic resonance images. All authors (ZJ, PJ, KSR, MLS, GD) contributed to the study design, drafted the work, and revised it critically for final submission. 2021;50(7):1399-409. Jibri, Z., Jamieson, P., Rakhra, K.S. Patella alta persists in this patient. Duke Radiology Case Review. b Axial MRI at the level of the tibial tuberosity. PubMed What is the diagnosis? These two structures blend with each other and are difficult to separate on imaging. Am J Sports Med 32:11141121, Tsavalas N, Katonis P, Karantanas AH (2012) Knee joint anterior malalignment and patellofemoral osteoarthritis: an MRI study. Another method is the CatonDeschamps index. Bethesda, MD 20894, Web Policies In this section, we will emphasize the role of MRI and discuss how CT can also have value when assessing patellar maltracking. MRI, given its superior soft tissue contrast and multi-planar capability, has emerged as the modality of choice in evaluating articular cartilage abnormalities. 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]. Phys Ther 69:897901, Atkin DM, Fithian DC, Marangi KS, Stone ML, Dobson BE, Mendelsohn C (2000) Characteristics of patients with primary acute lateral patellar dislocation and their recovery within the first 6 months of injury. (Figs.1-A 1-A also and1-B). Correspondence ML: [emailprotected] Submitted 07-19-2011. The most common trochleoplasty procedure described is a combination of lateral trochlear osteotomy and bone graft to heighten the lateral trochlea. The latter distinction is important to recognize among both radiologists and surgeons. Accessibility Cookies policy. 28 Areas of scarring and osteochondral lesions become more common as the frequency of patellar dislocation increases. 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. 7). Am J Sports Med 45:10591065, Brossmann J, Muhle C, Schrder C et al (1993) Patellar tracking patterns during active and passive knee extension: evaluation with motion-triggered cine MR imaging. MRI and operative studies have revealed that it is almost . 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. 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. 7). Trauma itself rarely causes patellofemoral dislocations without predisposing factors such as trochlear dysplasia, patella alta and lateralization of the tibial tuberosity. lateral patellar retinacular sleeve, mak-ing this particular avulsion a rare oc-currence. The .gov means its official. MRI plays a crucial role in quantification and characterization of these predisposing anatomic variations which are key to addressing the patient?s patellar instability operatively. Am J Sports Med 38:181188, Ali S, Bhatti A (2007) Arthroscopic proximal realignment of the patella for recurrent instability: report of a new surgical technique with 1 to 7 years of follow-up. (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). 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]. One of the more common MPFL reconstruction procedures uses a single hamstring tendon graft passed through the medial intermuscular septum at the adductor magnus insertion fixed by an anchor in the femoral condyle and sutured or anchored to the superomedial pole of the patella11. The patellar dislocations were clinically unsuspected in the initial evaluation of eight of these nine patients. 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. 8). 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. Medial patellofemoral ligament: cadaveric investigation of anatomy with MRI, MR arthrography, and histologic correlation. 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 superficial layer originates from the lowest fibers of the iliotibial band and from an extension of vastus lateralis fascia. Burks RT, Desio SM, Bachus KN, Tyson L, Springer K. Spritzer CE, Courneya DL, Burk DL Jr, Garrett WE, Strong JA. 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. It is therefore helpful in surgical planning. 6 Cone R. Patella Alta and Baja. If the lateral retinaculum tendon is tight enough to pull the patella out of the trochlear groove, a lateral release procedure can loosen the tissue and correct the patellar malalignment. TT-TG is a reflection of the clinically measured Q angle. Dr. Frederick Buechel, Jr. MD answered. (18a) A 13-year-old female following acute patellar dislocation. (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. Other structures combine to form the region referred to as the medial retinaculum (MR) more anteriorly. Injury of the superior peroneal retinaculum (SPR) occurs with peroneal dislocation through forceful ankle dorsiflexion and concomitant reflex peroneal muscle contraction. Skeletal Radiol. Additionally, return to sport can be as low as 45%, leaving many patients searching for further management options [12]. 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. 1 Pain is often described as medial because of soft tissue injuries that occur to the medial retinaculum and/or MPFL. PFA of 0 or if it opens medially (negative value) is considered abnormal indicating lateral patellar tilt [27, 48]. It is not until beyond 90 of flexion that the odd facet engages the medial femoral condyle and plays a role in load sharing along with lateral facet [6, 7]. 10 Diederichs G, Issever Ahi S, Scheffler S. MR Imaging of Patellar Instability: Injury Patterns and Assessment of Risk Factors. 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). A bone bruise occurs anterior to this site of impaction as the patella reduces with knee extension. 5 Carrillon Y, Abidi H, Dejour D, et al. The lateral retinaculum or lateral canthus is a complex integration of a number of structures. Trochlear geometry, including slope of the lateral wall and depth, is an important factor. CAS The site is secure. 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]. 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. Value of the tibial tuberosity-trochlear groove distance in patellar instability in the young athlete. Falls. 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. Less common predisposing factors to be aware of include laterally tilted patella, VMO dysplasia and generalized joint laxity. Acta Orthop 76:699704, Nikku R, Nietosvaara Y, Kallio PE, Aalto K, Michelsson JE (1997) Operative versus closed treatment of primary dislocation of the patella. 5). Transient lateral patellar dislocation. 11 Lind M, Jakobsen B, Lund B, et al. Pathology 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/. Distal neurovascular examination also needs to be performed [16]. Traumatic lateral patellar dislocation is a common injury among young, athletic individuals and is generally transient in nature. Of course, if medial soft tissue restraints are disrupted at the first dislocation, the loss of such restraints makes future dislocations more likely. Eleven gave a history of recurrent patellar dislocation. Normal = 0.8 to 1.2. Incidence and concomitant chondral injuries in a consecutive cohort of primary traumatic patellar dislocations examined with sub-acute MRI. Characterization of the type of medial restraint injury is crucial for surgical planning. In eight of 17 patients, the mechanism of injury was a patellar tendon tear (n = 1) or valgus hyperextension (n = 7). 2020;49(6):1642-50. These parameters can be evaluated using dynamic MRI [29]. Insights Imaging 10, 65 (2019). Our study focus was to evaluate medial patellofemoral ligament (MPFL) injury patterns and associated knee pathology using Magnetic Resonance Imaging studies. There is agreement, however, that the MPFL is almost always injured with lateral patellar dislocations4. 6). It can not only detect any underlying morphological risk factors but also look for structural damage associated with maltracking including patellofemoral articular cartilage loss, osteochondral defects, or damage to the medial patellar stabilizers [4, 5]. Am J Orthop (Belle Mead NJ) 46:290300, Dejour H, Walch G, Neyret P, Adeleine P (1990) Dysplasia of the femoral trochlea. 3. Skeletal Radiology 39:7, 675-682. Lateral patellar dislocation results in bone contusion at the medial patella and along the lateral aspect of the lateral femoral condyle. AJR Am J Roentgenol. The deep layer of the lateral retinaculum contains thickenings that form ligaments providing stabilizing support to the patella. Immobilization Regime Following Lateral Patellar Dislocation: A Systematic Review and Meta-Analysis of the Current Evidence Base. 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. The injured retinaculum had an indistinct, irregular appearance associated with edema and hemorrhage. Knee 13:266273. The patients are then J-braced for 3 to 6 months for all sports activities. 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. National Library of Medicine Discussion. 2. Eur J Trauma Emerg Surg. Depends on how bad: Small tears are observed and heal. 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. The most important soft tissue passive stabilizers involved in patellofemoral dislocation injuries have traditionally been referred to as the MPFL and the medial retinaculum. 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 discrimination between low-grade and high-grade dysplasia is important because prognosis and treatment may depend upon the severity of trochlear dysplasia. PMID: 9168713. Anatomical and radiology atlas of the abdomen and pelvis based on anatomical diagrams and cross-sectional CT and MRI imaging. 1997 Jan;168(1):117-22. doi: 10.2214/ajr.168.1.8976933. 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. is a term coined for anatomic characteristics that lead to an increased Q angle and an exacerbation of patellofemoral dysplasia. 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]. A lateral patellar sleeve fracture can be misdiagnosed The MCL is composed of the superficial layer (layer 2 of the medial supporting structures) and the deep layer (layer 3 of the medial . 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. Arthroscopy 23:305311, Kolowich PA, Paulos LE, Rosenberg TD, Farnsworth S (1990) Lateral release of the patella: indications and contraindications. At the time the article was created Pereshin Moodaley had no recorded disclosures. A second line is drawn parallel to a line along the posterior femoral condyles. We confirm that this article is not under consideration for publication elsewhere and that the authors did not receive any specific grants from funding agencies in the public, commercial, or not-for-profit sectors. Medial patellar chondral injuries may occur during either the dislocation or reduction phases of injury. 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. Radiology 263:469474, Subhawong TK, Eng J, Carrino JA, Chhabra A (2010) Superolateral Hoffas fat pad edema: association with patellofemoral maltracking and impingement. The ensuing loss of medial restraint favors future patellar dislocations, especially if additional risk factors are present. Trochlear depth of less than 3 mm on MRI has a sensitivity of 100% and a specificity of 96% for trochlear dysplasia.10. Google Scholar, Amis AA, Firer P, Mountney J, Senavongse W, Thomas NP (2003) Anatomy and biomechanics of the medial patellofemoral ligament. Unauthorized use of these marks is strictly prohibited. Patellar maltracking occurs as a result of an imbalance in the dynamic relationship between the patella and trochlea. The typical injury pattern is a tear of the medial patellofemoral ligament (MPFL) and bone bruises of the patella and the lateral femoral condyle. 3.1 ). The clinical evaluation of patellar maltracking is often challenging, Imaging can detect subtle features that could lead to early diagnosis, Imaging can detect predisposing factors for patellar maltracking and associated structural changes, Management decisions are made on individual basis with imaging playing a vital role. 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. 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. In: West RV, Colvin AC (eds) The patellofemoral joint in the athlete. Google Scholar, Fithian DC, Paxton EW, Stone ML et al (2004) Epidemiology and natural history of acute patellar dislocation. 2002 Dec;225(3):736-43. doi: 10.1148/radiol.2253011578. It has been shown that there is an association between edema at the superolateral aspect of Hoffas fat pad and a number of patellar maltracking parameters [30, 54, 55]. Kim et al. There are a number of MRI features of trochlear dysplasia including reduction in the trochlear depth, lateral trochlear inclination, and facet asymmetry. 9). In the setting of osseous patellar malalignment, an osseous procedure such as tibial tubercle transfer osteotomy can be performed (Fig. 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]. Knee 13:2631, McNally EG (2001) Imaging assessment of anterior knee pain and patellar maltracking. 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. A thorough examination of the knee is then performed including presence of effusion, localization of pain, assessment of patellar translation, patellar apprehension, presence of a J sign (visual lateralization of the patella as it disengages from the trochlea when extending the knee), and a measurement of the Q angle along with ligamentous and meniscal testing.