Lastly, a sulcus-deepening procedure known as trochleoplasty may be indicated in the patient with significant trochlear dysplasia and recurrent instability. 0000293749 00000 n Injury 4:126130, 1972. 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. 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]. Curr Sports Med Rep 11:226231, Jain NP, Khan N, Fithian DC (2011) A treatment algorithm for primary patellar dislocations. Migliorini F, Marsilio E, Cuozzo F, Oliva F, Eschweiler J, Hildebrand F, Maffulli N. Life (Basel). The common peroneal nerve can be localized in the popliteal fossa or identified posterior to the biceps femoris tendon and followed as it courses around the fibular neck. Clin Radiol 59:543557, Ali SA, Helmer R, Terk MR (2010) Analysis of the patellofemoral region on MRI: association of abnormal trochlear morphology with severe cartilage defects. (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 MCL is composed of the superficial layer (layer 2 of the medial supporting structures) and the deep layer (layer 3 of the medial . Excessive lateralization of the tibial tuberosity allows the patella to be pulled laterally in flexion and is considered to be a risk factor for instability. Do a thorough work-up of the patient at the clinic to determine the need for a redesign total knees arthroplasty (Figs. A bone bruise occurs anterior to this site of impaction as the patella reduces with knee extension. Lateral Patellar Dislocation. 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. 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]. The most obvious presentation of patellar maltracking is that of the first time lateral patellar instability or recurrent instability thereafter. Radiology 189:905907, Warren LF, Marshall JL (1979) The supporting structures and layers on the medial side of the knee: an anatomical analysis. 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. Patellar tracking refers to the dynamic relationship between the patella and trochlea during knee motion [1]. 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 a geometric abnormality of the trochlear groove that affects its shape and depth mainly at its superior part, which can result in abnormal tracking of the patella along the trochlea. 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. The medial patellofemoral ligament (MPFL) is a condensation of the medial capsule of the knee joint. This injury has been described in conjunction with numerous sports activities, particularly snow skiing. The radiograph can be helpful in the acute presentation in detecting fractures in the setting of lateral (often transient) patellar dislocation. However, in the setting of osseous malalignment, MPFL reconstruction alone leads to higher rates of recurrent instability. 2). By using this website, you agree to our 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. 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. CT of both knees in 20 flexion demonstrating bilateral shallow trochlear groove (arrows) compatible with dysplasia and bilateral lateral patellar subluxation and lateral tilt. AJR Am J Roentgenol 169:211215, Buchner M, Baudendistel B, Sabo D, Schmitt H (2005) Acute traumatic primary patellar dislocation: long-term results comparing conservative and surgical treatment. TT-TG is a reflection of the clinically measured Q angle. Methods: We compared 361 treated cases of aneurysm occlusion after subarachnoid hemorrhage from 1997 to 2003 with 281 cases from 2006 to 2014. 1-31. Yu JS, Goodwin D, Salonen D, Pathria MN, Resnick D, Dardani M, Schweitzer M. AJR Am J Roentgenol. Dejour et al. AJR Am J Roentgenol. Starok M, Lenchik L, Trudell D, Resnick D. Normal patellar retinaculum: MR and sonographic imaging with cadaveric correlation. Additional passive stabilizers include the medial patellotibial ligament (MPTL) and the medial patellomeniscal ligament (MPML). 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/. Division of Sports Trauma, Department of Orthopaedics, Aarhus University Hospital, Aarhus, Denmark. Persistent abnormalities of patellar alignment and abnormalities of trochlear morphology are also common, and should be carefully described. 2023 BioMed Central Ltd unless otherwise stated. 1993;161(1):109-13. Less commonly, patients can also present after chronic patellar instability secondary to generalized ligamentous laxity with or without anterior knee pain. Elsevier, Philadelphia, Buckens CF, Saris DB (2010) Reconstruction of the medial patellofemoral ligament for treatment of patellofemoral instability: a systematic review. Knee 13:2631, McNally EG (2001) Imaging assessment of anterior knee pain and patellar maltracking. Sonographic Appearances of Medial Retinacular Complex Injury in 1835 31 - 40 27 30.0 41 - 50 22 24.4 50 + 4 4.4 Total 90 100.0 Age Distribution Number Percent Sex Female 19 21.1 Male 71 78.9 The PubMed wordmark and PubMed logo are registered trademarks of the U.S. Department of Health and Human Services (HHS). 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]. Medial Patellofemoral Ligament (MPFL) - Physiopedia Med Sci Sports Exerc 35:20432047, Steiner T, Parker RD (2009) Patella: subluxation and dislocation. 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. At the time the article was created Pereshin Moodaley had no recorded disclosures. 20,61 This is attributable to a medial retinacular injury, specifically, avulsion or tearing of the medial patellofemoral ligament. It has been suggested that fat impingement occurs between the lateral femoral condyle and the posterior aspect of the patellar tendon [54]. Acute lateral patellar dislocation at MR imaging: injury patterns of Infrapatellar (Hoffas) fat pad impingement is recognized as a cause of anterior knee pain. Sports Med Arthrosc Rev 15:7277, Mikashima Y, Kimura M, Kobayashi Y, Miyawaki M, Tomatsu T (2006) Clinical results of isolated reconstruction of the medial patellofemoral ligament for recurrent dislocation and subluxation of the patella. 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. Depends on how bad: Small tears are observed and heal. Various parameters can be used in assessing and predicting the presence of patellar maltracking. Value of the tibial tuberosity-trochlear groove distance in patellar instability in the young athlete. National Library of Medicine Traumatic lateral patellar dislocation is a common injury among young, athletic individuals and is generally transient in nature. and transmitted securely. PubMed Given the lack of history of direct trauma, a reliable diagnosis can be made. The ratio of the medial to the lateral facet length defines trochlear facet asymmetry (MT/LT) *100%. 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). Twenty-seven knees in 21 patients were studied and the mean age of the patients at surgery was 19 years. In full extension, the patella has little to no contact with the trochlear groove and, therefore, is in a position of higher risk for instability. 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. MRI can provide valuable information regarding the status of such repairs in patients who experience recurrent dislocation following surgery. Femoral osteochondral injuries, when present, typically involve the lateral weightbearing surface. Bookshelf 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. Other structures that blend in this region include the medial patellotibial ligament, the medial patellomeniscal ligament, the investing fascia, and the medial joint capsule. The most important soft tissue passive stabilizers involved in patellofemoral dislocation injuries have traditionally been referred to as the MPFL and the medial retinaculum. In: West RV, Colvin AC (eds) The patellofemoral joint in the athlete. 2. 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. Surgical repair is most commonly directed to MPFL reconstruction and to distal realignment in the subset of patients who have significant osseous malalignment. 5). This distance is the trochlear sulcus depth (TD). The VMO blends distally with the MPFL to attach to the medial border of the patella along its upper two thirds. Bone bruise in acute traumatic patellardislocation: volumetric magnetic resonance imaging analysis with follow-up mean of 12 months. Physical Therapy. As is typical, a bone bruise extends anteriorly (arrowheads) from the site of the chondral defect. Google Scholar, Sanders TG, Paruchuri NB, Zlatkin MB (2006) MRI of osteochondral defects of the lateral femoral condyle: incidence and pattern of injury after transient lateral dislocation of the patella. Radiology. Anatomically, the transverse band of the MPFL is also a component of the medial retinaculum, but for purposes of MRI interpretation, the general convention is to describe abnormalities of the transverse band as being MPFL injuries, whereas more distal injuries which involve multiple layers are generally referred to as abnormalities of the medial retinaculum. The deep layer of the lateral retinaculum contains thickenings that form ligaments providing stabilizing support to the patella. (5a) An axial T1-weighted image demonstrates the low blending fibers of the VMO and transverse MPFL at their attachment along the upper patella. The discrimination between low-grade and high-grade dysplasia is important because prognosis and treatment may depend upon the severity of trochlear dysplasia. In one MRI study, 76% of cases of prior lateral patellar dislocation showed medial retinacular injury at its patellar insertion and 30% at its midsubstance, and injury of the femoral origin of the MPFL was identified in 49% of the cases [49]. Knee 13:266273. The lateral trochlear articular surface is usually more prominent than its medial portion. The patellar retinaculum and the MPFL are seen on MRI as well-defined low-signal-intensity bands. 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. 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. 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]. Management of Patellofemoral Pain Syndrome | AAFP Direct impact to the front of the knee from a fall or other blow is a common cause of tears. AJR Am J Roentgenol 1997; 168:117-122. Am J Knee Surg 13:8388, Izadpanah K, Weitzel E, Vicari M et al (2014) Influence of knee flexion angle and weight bearing on the Tibial Tuberosity-Trochlear Groove (TTTG) distance for evaluation of patellofemoral alignment. James M. Provenzale, Rendon C. Nelson, Emily N. Vinson. LTI < 11 degrees indicates dysplasia. All authors read and approved the final manuscript. Facet asymmetry is determined by calculating the percentage of the medial to the lateral femoral facet length (Fig. The authors declare that they have no competing interests. 8600 Rockville Pike The patella remains laterally shifted (blue arrow) and an osteochondral injury of the medial patella (arrowheads) is apparent. There is a degree of variability in the literature about what is considered an abnormally high TT-TG. 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]. The lateral patellar retinaculum is a fibrous expansion comprising of superficial and deep layers. The lateral retinaculum is a ligament that helps hold your patella, or kneecap, in place. AJR Am J Roentgenol. Acute lateral patellar dislocation at MR imaging: injury patterns of medial patellar soft-tissue restraints and osteochondral injuries of the inferomedial patella. AJR Am J Roentgenol 1997; 168:1493-1499. Eleven gave a history of recurrent patellar dislocation. Clinical History: A 23 year-old female presents with medial knee pain following a twisting injury. 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). To provide the highest quality clinical and technology services to customers and patients, in the spirit of continuous improvement and innovation. Subluxation and dislocation: recurrent. Knee Surg Sports Traumatol Arthrosc 13:522528, Farr J, Schepsis AA (2006) Reconstruction of the medial patellofemoral ligament for recurrent patellar instability. b Axial CT image showing tibial tuberosity transfer surgery with screw placement (arrow). J Knee Surg 28:303309, Hevesi M, Heidenreich MJ, Camp CL et al (2019) The recurrent instability of the patella score: a statistically based model for prediction of long-term recurrence risk after first-time dislocation. The convex articular surface of the patella places it at risk for chondral injury in either the dislocation or the reduction phases of injury. Stretching a Lateral Retinaculum of the Knee | livestrong 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. The medial patellar retinaculum is part of the anterior third of the medial joint capsule. As an example, although the InsallSalvati ratio is one of the most commonly used methods and does not depend on the degree of knee flexion, it is affected by the patellar shape particularly its inferior point and measurement does not change after tibial tubercle distalization procedure [25]. Diederichs G, Issever A, Scheffler S. MR Imaging of Patellar Instability: Injury Patterns and Assessment of Risk Factors. The literature in this field has been extremely heterogeneous, and this has made clinical guidelines difficult to produce. The anatomy of the medial patellofemoral ligament. Nontraumatic Knee Pain: A Diagnostic & Treatment Guide 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. For first-time dislocators without intra-articular loose bodies or chondral injury, a trial of nonoperative therapy is indicated.