lateral patellar retinaculum injury radiology

Radiology 1993; 189:905-907. J Comput Assist Tomogr 2001; 25:957-962. 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 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. In the past two decades dissection studies have shown that it extends from the superomedial border of the patella to the femoral epicondyle, at or immediately above the adductor tubercle. Another method is the CatonDeschamps index. 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]. Significantly greater lateral patellar displacement and tilt was found in osteoarthritis patients compared to a control group [3]. 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]. 4. The radiograph can be helpful in the acute presentation in detecting fractures in the setting of lateral (often transient) patellar dislocation. Yu JS, Goodwin D, Salonen D, Pathria MN, Resnick D, Dardani M, Schweitzer M. AJR Am J Roentgenol. 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. 2015 Sep 30;9:463-74. doi: 10.2174/1874325001509010463. To provide the highest quality clinical and technology services to customers and patients, in the spirit of continuous improvement and innovation. Femoral condylar chondral injuries occur during the dislocation phase due to impaction shearing forces of the patella upon the flexed femur, typically occurring at the weightbearing surface. 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. These are most often found at the inferomedial patella or the lateral femoral condyle [49, 61, 62]. Knee Surg Sports Traumatol Arthrosc 15:13011314, Tom A, Fulkerson JP (2007) Restoration of native medial patellofemoral ligament support after patella dislocation. The primary aim of surgery is to repair the knee damage and to correct the anomalies that are predisposing to chronic instability. The MCL is beneath the deep crural fascia (layer 1), from which it is separated by a variable amount of fat (Fig. Rev Bras Ortop 46:160164, LeGrand AB, Greis PE, Dobbs RE, Burks RT (2007) MPFL reconstruction. (20a) A fat-suppressed proton density-weighted sagittal image in a patient following patellar dislocation reveals an osteochondral injury with a chondral defect (arrows) at the lateral weightbearing surface of the lateral femoral condyle, a finding seen in only 5% of patients. Google Scholar, Nakagawa S, Kadoya Y, Kobayashi A, Tatsumi I, Nishida N, Yamano Y (2003) Kinematics of the patella in deep flexion. Clipboard, Search History, and several other advanced features are temporarily unavailable. 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. 5). Post WR, Teitge R, Amis A (2002) Patellofemoral malalignment: looking beyond the viewbox. The lateral retinaculum appears as a hyperechoic band originating from the iliotibial band and the vastus lateralis muscle. 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. Dejour et al. Techniques for quantifying trochlear dysplasia with MRI have been standardized and shown to be accurate and reproducible in assessing lateral trochlear inclination, facet asymmetry, and trochlear depth8,9. . (2011) ISBN: 9780781778602 -. All authors (ZJ, PJ, KSR, MLS, GD) contributed to the study design, drafted the work, and revised it critically for final submission. Would you like email updates of new search results? California Privacy Statement, Rethy Chhem, Etienne Cardinal. In patients without osseous malalignment, MPFL reconstruction and plication of the medial restraints is reported to decrease re-dislocation rates to 5%. Risk factors for recurrent patellar dislocations include 5: The presence of an abnormal medial patellar retinaculum should suggest the diagnosis of transient lateral patellar dislocation 1. 2000; 216:858-864. 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. There is agreement, however, that the MPFL is almost always injured with lateral patellar dislocations4. It takes a very strong force to tear the patellar tendon. PubMed Central Google Scholar, Diederichs G, Issever AS, Scheffler S (2010) MR imaging of patellar instability: injury patterns and assessment of risk factors. 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]. However, subtle sprains are seen at the anterior medial retinaculum (arrowhead) and posterior MPFL (arrow) along with a large joint effusion. 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 . MRI is the imaging modality of choice in the assessment of patellar maltracking, as a virtue of what it can reveal (Table1). The lateral retinaculum or lateral canthus is a complex integration of a number of structures. [Nov;2019 . 2012;40(4):837-844. official website and that any information you provide is encrypted The .gov means its official. a Axial PDFS right knee MR image at the level of the trochlear groove. 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. Medial retinacular complex injury in acute patellar dislocation: MR findings and surgical implications. 5 a-d). 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. Patellar maltracking occurs as a result of imbalance of this relationship often secondary to anatomic morphologic abnormality. MR imaging can help define patellar retinacular and associated osteochondral injuries, which may be clinically useful information. Epidemiology Patellar dislocation accounts for ~3% of all knee injuries and is commonly seen in those individuals who participate in sports activities. Despite non-operative management, recurrent patellar instability occurs in between 15 and 45% of patients [17,18,19,20]. 3 Dirim B, Haghighi P, Trudell D et al. 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. PubMed Prevalence of Lateral Patellofemoral Maltracking and Associated Complications in Patients with Osgood Schlatter Disease. Privacy 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. 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. Immobilization Regime Following Lateral Patellar Dislocation: A Systematic Review and Meta-Analysis of the Current Evidence Base. Eur J Trauma Emerg Surg. Observer Agreement on the Dejour Trochlear Dysplasia Classification: A comparison of true lateral radiographs and axial magnetic resonance images. CAS The TT-TG index is the TTTG/TT-TE ratio [44]. Normal = 0.8 to 1.2. Dr. Frederick Buechel, Jr. MD answered. Orthopedic Surgery 22 years experience. (21a) A corresponding anterior coronal slice reveals the large displaced osteochondral fragment (arrow) that occurred as a result of this injury. 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. Kirsch M, Fitzgerald S, Friedman H, Rogers L. Transient Lateral Patellar Dislocation: Diagnosis with MR Imaging. PMID: 9168713. Analysis with magnetic resonance imaging. The main morphological features associated with patellar maltracking are trochlear dysplasia, lateralization of the tibial tuberosity, patella alta, and lateral patellar tilt. The tight structures of the knee such as the lateral retinaculum need to be stretched and mobilized. Tears of the medial retinaculum and the MPFL are commonly present at both the patellar and femoral attachments, though tears of the transverse band of the MPFL are more likely at the femoral attachment. Asymmetry of <40% suggests trochlear dysplasia [24]. Less commonly, a direct laterally or medially orientated blow to the patella can precipitate dislocation. It can be difficult to determine the deepest part of the trochlear groove when assessing the TT-TTG in the presence of trochlear dysplasia; therefore, an alternative method for assessing tibial tubercle position was proposed measuring the distance in reference to the posterior cruciate ligament and not to the trochlea (tibial tubercle-posterior cruciate ligament distance [TT-PCL]), with proposed pathologic threshold of 21mm [42, 43]. At the time the article was last revised Joel Hng had 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. MRI and CT are superior modalities in looking for predisposing factors associated with patellar maltracking [26,27,28]. 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. Trochlear depth of less than 3 mm on MRI has a sensitivity of 100% and a specificity of 96% for trochlear dysplasia.10. Normal TD > 5.2mm. The contralateral side may serve as an internal control or may also have anatomic factors predisposing to maltracking. Specialists of neuroradiology and vascular neurosurgery decided over the modality assignment. There is a degree of variability in the literature about what is considered an abnormally high TT-TG. Correspondence ML: [emailprotected] Submitted 07-19-2011. Check for errors and try again. 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. 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]. 1997 Jun;168(6):1493-9. doi: 10.2214/ajr.168.6.9168713. 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. At the time the article was created Pereshin Moodaley had no recorded disclosures. Depends on how bad: Small tears are observed and heal. 2023 Apr;47(4):973-981. doi: 10.1007/s00264-023-05707-y. These two structures blend with each other and are difficult to separate on imaging. It is therefore helpful in surgical planning. The axial proton density-weighted image reveals a large osteochondral shearing injury involving the mid to medial patella (arrowheads). Lateral patellar dislocation is a common clinical entity with a characteristic MR appearance. Both knees are scanned simultaneously. A generalized physical examination assessing ligamentous laxity and rotational profile of the lower extremity is critical. The technique has been refined, and a better understanding of the anatomical features of both the origin and insertion of the ligament onto the patella has made the operation more reproducible (Fig. LTI < 11 degrees indicates dysplasia. 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. A tear of the retinaculum is mostly seen after dislocation of the patella. 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. Lateral patellar compression syndrome is the improper tracking of the patella in the trochlear groove generally caused by a tight lateral retinaculum. This injury has been described in conjunction with numerous sports activities, particularly snow skiing. 25a) Axial proton density-weighted images at initial injury (left) and 5 months later demonstrate progression of medial retinacular and MPFL scarring (arrows) in this patient with trochlear dysplasia and chronic patellofemoral instability with a history of multiple prior dislocations. Observer Agreement on the Dejour Trochlear Dysplasia Classification: A comparison of true lateral radiographs and axial magnetic resonance images. Knee Surg Sports Traumatol Arthrosc 26:27332742, Hingelbaum S, Best R, Huth J, Wagner D, Bauer G, Mauch F (2014) The TT-TG Index: a new knee size adjusted measure method to determine the TT-TG distance. 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 medial patellar retinaculum and MPFL are best seen on MRI on the axial fluid-sensitive sequences. An increased tibial tubercletrochlear groove (TT-TG) indicates a lateralized tibial tuberosity, or a medialized trochlear groove [38]. no financial relationships to ineligible companies to disclose. A buckle transducer was clamped on the lateral patellofemoral ligament and the transducer was calibrated to zero with the knee at full extension. RadioGraphics 2010; 30: 961-981. Zaid Jibri. Correspondingly, the patella must shift slightly medially during early flexion to engage the trochlear groove. Am J Sports Med. AJR Am J Roentgenol 195:13671373, Jarraya M, Diaz LE, Roemer FW, Arndt WF, Goud AR, Guermazi A (2018) MRI findings consistent with peripatellar fat pad impingement: how much related to patellofemoral maltracking? The pages that follow contain general guidance on the diagnosis and treatment of chronic nontraumatic knee pain. 5 Carrillon Y, Abidi H, Dejour D, et al. 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. The injured retinaculum had an indistinct, irregular appearance associated with edema and hemorrhage. 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. The lateral patellar retinaculum (LPR) is located on the anterolateral aspect of the knee joint and extends to the femur transversely and obliquely from the lateral margin of the patella [].It plays an important role in patellar stability, and patellar instability can be caused by abnormal tension or tightness in the LPR [].The LPR is a complex structure composed of various merging fascial layers. 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. By using this website, you agree to our The injury typically occurs from a twisting event with the knee in mild flexion (less than 30). 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]. Google Scholar, Miller TT, Staron RB, Feldman F (1996) Patellar height on sagittal MR imaging of the knee. 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/. The ratio of the medial to the lateral facet length defines trochlear facet asymmetry (MT/LT) *100%. An association has been demonstrated between patellofemoral cartilage damage and patellar maltracking. Insights Imaging 10, 65 (2019). The superficial layer originates from the lowest fibers of the iliotibial band and from an extension of vastus lateralis fascia. Edema and thickening compatible with tears of the MPFL and medial retinaculum (red arrows) are apparent both anteriorly and posteriorly. A ratio > 1.3 indicates patella alta. The joint line is scanned for lateral meniscal pathology, with varus stress applied as needed. 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. (14a) A fat-suppressed proton density-weighted coronal image following patellar dislocation reveals the classic lateral condylar bone bruise (arrow). 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. and transmitted securely. Surgical realignment procedures include medialization of the tibial tubercle particularly in patients with a TT-TG distance greater than 20mm. 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. It thickens as it inserts onto the lateral border of the patella, quadriceps tendon and patellar ligament. The medial patellar retinaculum (MPR) and the lateral patellar retinaculum (LPR) are vital structures for the stability of the patella. The normal trochlea is concave with medial and lateral facets articulating with the patellar facets. Osteochondral fractures are common in acute or recurrent transient lateral patellar dislocation, seen in up to 70% of cases. The most accepted indication for surgical management of patellar instability is the presence of a large displaced osteochondral fracture or loose body. There are numerous techniques reported in literature and commonly used to reconstruct the medial sided soft tissue constraints. Long term follow up studies in patients who have undergone a lateral release have shown an increased incidence of patellofemoral arthritis. 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. J Pediatr Orthop 37:484490, Parikh SN, Lykissas MG, Gkiatas I (2018) Predicting risk of recurrent patellar dislocation. On the other hand, frank patellar dislocation is a significant risk factor in the development of patellofemoral osteoarthritis with an incidence of 49% at 25years after the patellar dislocation incident in comparison with 8% in a control group without a dislocation history [60]. Distances between 15 and 20 mm are borderline, and distances of more than 20 mm indicate significant lateralization of the tuberosity.5. Medial patellofemoral ligament: cadaveric investigation of anatomy with MRI, MR arthrography, and histologic correlation. (Figs.1-A 1-A also and1-B). Bone bruise in acute traumatic patellardislocation: volumetric magnetic resonance imaging analysis with follow-up mean of 12 months. CAS Facet asymmetry is determined by calculating the percentage of the medial to the lateral femoral facet length (Fig. Lateral patellar retinaculum. Another study noted an association between abnormal trochlear morphology and high-grade patellofemoral cartilage damage [58]. Am J Sports Med. Eleven gave a history of recurrent patellar dislocation. Focal Defect at the LPR on Clinical Knee MRI and a Cadaveric Study Musculoskeletal Imaging Original Research. Usually, young individuals, particularly women, suffer the consequences of this disorder [2]. The VMO blends distally with the MPFL to attach to the medial border of the patella along its upper two thirds. The convex articular surface of the patella places it at risk for chondral injury in either the dislocation or the reduction phases of injury. A ratio of >1.3 is considered indicative of patella alta [34] (Fig. Springer Nature. The adductor magnus tendon (AT) attaches to the adductor tubercle, which lies posterior and superior to the femoral attachment of the MPFL. Although you may feel that being asked to make the specific diagnosis of lateral patellar dislocation from a single image is unrealistic, the coronal view in fact reveals a classic and highly characteristic appearance, allowing the diagnosis to be made with confidence. Lateral patellar dislocation results in bone contusion at the medial patella and along the lateral aspect of the lateral femoral condyle. Additionally, complex injuries to bone, cartilage, and ligaments may occur. What is the diagnosis? 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. The decreased patellar contact area decreases stability particularly in shallow degrees of flexion and thus predisposes to lateral patellar subluxation. Clinical History: A 23 year-old female presents with medial knee pain following a twisting injury. AJR Am J Roentgenol. Other structures combine to form the region referred to as the medial retinaculum (MR) more anteriorly. 2010;30(4):961-81. Because of the transient and brief nature of lateral patellar dislocations, the diagnosis is frequently unrecognized by both patients and clinicians. 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]. (18a) A 13-year-old female following acute patellar dislocation. These parameters can be evaluated using dynamic MRI [29]. 2012 Feb;41(2):137-48. doi: 10.1007/s00256-011-1291-3. 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. The patella has 4 different planes of motion: flexionextension, mediallateral rotation, mediallateral patellar tilt, and mediallateral patellar shift. 8). Terms and Conditions, Failure to identify or treat injury to the patellar retinaculum is associated with recurrent patellar instability and contributes to significant morbidity. The distance (double-headed arrow) from the deepest point of the trochlea (line B) to the middle of the tibial tubercle (line A) is measured, again by using the posterior plane of the condyles as the reference line (line C). TT-TG distance of more than 20mm is believed to be nearly always associated with patellar instability [27]. Patellar maltracking is a disorder that often affects the young active individuals. 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. Because the diagnosis of lateral patellar dislocation is often unsuspected, MR provides valuable diagnostic information in such cases. Materials and methods: Two radiologists independently reviewed 99 knee MR images for the presence of a focal defect at the lateral patellar retinaculum and . It is the percentage of the medial (a) to the lateral (b) trochlear facet length (a/b100%). 1 Pain is often described as medial because of soft tissue injuries that occur to the medial retinaculum and/or MPFL. ADVERTISEMENT: Supporters see fewer/no ads, Please Note: You can also scroll through stacks with your mouse wheel or the keyboard arrow keys. Lateral patellar dislocation. 1 Lance E, Deutsch AL, Mink JH. This short surgical video demonstrates an arthroscopic lateral release as seen from inside the knee. 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. Radiology 189:905907, Warren LF, Marshall JL (1979) The supporting structures and layers on the medial side of the knee: an anatomical analysis. 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]. The lateral patellar retinaculum is a fibrous expansion comprising of superficial and deep layers. Cochrane Database Syst Rev 2:CD008106, Woo R, Busch MT (1998) Management of patellar instability in children. Do a thorough work-up of the patient at the clinic to determine the need for a redesign total knees arthroplasty (Figs. Patella alta assessment. 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. J Bone Joint Surg Am Volume 90:27512762, Dixit S, Deu RS (2017) Nonoperative treatment of patellar instability. 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. On T2-weighted MR images, sprain is depicted as thickening of retinaculum with signal intensity signifying edema and hemorrhage (Fig. In either case, careful search for possible displaced osteochondral fragments is necessary, as surgery is often indicated in such patients. ity. 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.

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