Patellar axial dislocation measurements (A- Normal, B Patellar luxation): A- Tangential line to femoral condyles. RadioGraphics 2010; 30:961981. 3, World Journal of Methodology, Vol. 2, Knee Surgery, Sports Traumatology, Arthroscopy, Vol. 1, Arthroscopy: The Journal of Arthroscopic & Related Surgery, Vol. Findings: The extensor mechanism, including the quadriceps tendon, patella, and patellar tendon, is normal. 6, Revue de Chirurgie Orthopdique et Traumatologique, Vol. This corresponds to the study done by Pfirrmann et al. In this study, we have attempted to evaluate the predisposing factors of patellar instability on magnetic resonance imaging (MRI) and to compare the significance of measurement at the level of trochlear bone versus cartilage for trochlear dysplasia. Nonetheless, both the MRI and surgical results suggest that lateral femoral condyle osteochondral lesions are common, and a search pattern should include an evaluation of the femoral condyle articular surface in both the sagittal and coronal imaging planes after transient dislocation of the patella. The average annual incidence of primary patellar dislocation has been reported to be 5.8 cases per 100 000, and the rate is higher for younger and more active populations. Instability of patellofemoral joint is associated with the presence of various anatomic predisposing factors. Treasure Island (FL): StatPearls Publishing; 2022 Jan. Knee Surgery, Sports Traumatology, Arthroscopy, Arthroscopy: The Journal of Arthroscopic & Related Surgery, Vol. 2021 Jul;87:105406. doi: 10.1016/j.clinbiomech.2021.105406. 46, No. 21, No. MPFL reconstruction for recurrent patella dislocation: a new surgical technique and review of the literature. 2, Techniques in Knee Surgery, Vol. Elsevier; 13 edition, December 2016. 9, The American Journal of Sports Medicine, Vol. The osteochondral defects were full-thickness (grade 4) chondral defects with exposure of the subchondral bone in seven (70%) of 10 patients and full-thickness chondral defects with underlying cortical abnormalities (grade 5) in three (30%) of 10 patients. 46, No. FOIA A patella fracture may be very subtle; The presence of a joint effusion (haemarthrosis or lipohaemarthrosis) in the context of trauma is a helpful indicator of a fracture 15, No. An official website of the United States government. 2). | Epub 2007 Sep 18. 4, Revista Mdica Clnica Las Condes, Vol. Prevalence of patellar instability is higher in younger population, more frequently involving age equal to or <25 years. Hip & Knee. PURPOSE: The authors describe magnetic resonance (MR) imaging findings of acute traumatic dislocation of the patella. Here, a line was drawn perpendicular to the posterior plane of femoral condyles such that it depicted deepest sulcal point. 40, No. 1, Knee Surgery, Sports Traumatology, Arthroscopy, Vol. WebDislocations occur when two bones that originally met at the joint detach. The cyclops lesion, also known as localized anterior arthrofibrosis, is a painful anterior knee mass that arises as a complication of anterior cruciate ligament (ACL) reconstruction, although has rarely been reported in patients with ACL injuries that have not been reconstructed. Anomalies of dynamic and static factors, including excessive patellar height, tibial tubercle lateralisation or trochlear dysplasia, may influence the development of the patella. The dimensions of the chondral defects were described in the operative report in only three of those six patients. The average size of the defects was 1.2 cm in the anteroposterior diameter and 1.0 cm in the transverse diameter. 45, No. Lipohaemarthrosis is a layered effusion of fat and blood which has 'leaked' from the bone following a fracture. Vertebra plana (plural: vertebrae planae), also known as the pancake, silver dollar or coin-on-edge vertebra, is the term given when a vertebral body has lost almost its entire height anteriorly and posteriorly, representing a very advanced compression fracture.. Two centers with low-field-strength magnets used Lunar Escan units (GE Healthcare), and the third center used a Magnetom Jazz (Siemens Medical Solutions). 3, International Orthopaedics, Vol. As the late sequelae, there may be lateral spurring (especially in children) 5. 24, No. Materials and methods: Knee MR images obtained within 8 weeks after LPD were evaluated for medial retinacular and medial patellofemoral ligament (MPFL) Previous studies have shown that high-field-strength systems provide significantly better diagnostic performance than the low-field-strength systems when evaluating grade 2 or 3 chondral defects, but low-field-strength systems can reliably evaluate high-grade chondral lesions, possibly because they imbibe joint fluid, thus providing adequate contrast [15, 16]. eCollection 2022 Dec. [17]) and at the level of trochlear bone (in accordance with Diederichs et al. 29, No. 1, The American Journal of Sports Medicine, Vol. Forty-eight percent (39 of 82) showed more than one site of injury to the medial stabilizers; 45% (37 of 82) showed edema or hemorrhage at the inferior VMO. Conveniently the Salter-Harris types can be remembered by the mnemonic SALTR.. type I. slipped; 5-7%; fracture plane passes all the way through Of the 25 patients for whom there was MRI evidence of prior transient dislocation of the patella, 10 (40%) were found to have chondral defects involving the articular surface of the lateral femoral condyle. In: StatPearls [Internet]. Login or register to get started. Each of the lateral femoral chondral defects in our series was a full-thickness chondral defect with or without underlying cortical abnormality, which is similar to the findings reported by Swischuk et al. Also, we found a significant association between trochlear dysplasia stage 3 and tibial tuberosity-trochlear groove (TT-TG) and patellar tilt relaxed (P < 0.01 and P < 0.05, respectively). [15] According to Fithian et al., maximum cases of recurrent LPD were found in the age group of 1017 years with females more commonly affected than males. 1, Current Problems in Diagnostic Radiology, Vol. 37, No. A larger sample size with a control group would definitely be more validating. government site. Medial epicondyle fractures are often associated with elbow dislocation and make up approximately 12-20% of all pediatric elbow fractures 5,6. 25, No. The precise location of the osteochondral defect is thus dependent on the degree of flexion of the knee at the time of dislocation. Insufficiency fractures are a type of stress fracture, which are the result of normal stresses on abnormal bone. 2022 Sep 18. The location of the lateral femoral condyle marrow edema was recorded relative to the position of the chondral defect. Conry KT, Cosgarea AJ, Tanaka MJ, Elias JJ. Acta ortop. 2, The American Journal of Sports Medicine, Vol. [1,2,5], Femoral trochlea and patella articulate to form the patellofemoral joint. [1] Methods: Patellofemoral instability is a clinical syndrome due to morphologic or dynamic changes in patellofemoral joint that lead to anterior knee pain and predispose to recurrent lateral patellar dislocation. However, only 7 cases (23.3 %) were positive for increased TT-TG distance in our study. 1, Singapore Medical Journal, Vol. Additional MRI sequences were used whenever required. Ten cases (33.33%) were positive for decreased lateral trochlear inclination. [3] Materials and methods: 7, No. 1, Radiologic Clinics of North America, Vol. 17, American Journal of Roentgenology, Vol. Trochlear depth was measured using the following equation: (A+C)/2B. Transient lateral patellar dislocation is a common injury that typically occurs in the young, athletic individual. Mechanism. Pathology. 2, The American Journal of Sports Medicine, Vol. It is usually due to trauma sustained during physical or sports activity. 32, No. 1). [9]. Injury. 47, No. 8, Journal of Pediatric Orthopaedics, Vol. At the time of this study, eight (80%) of the 10 patients with osteochondral injuries of the lateral femoral condyle identified on MRI had undergone follow-up arthroscopic surgery. Online ahead of print. This site needs JavaScript to work properly. Conclusion: In two (20%) of the 10 patients, the osteochondral defects involved the articular surface of both the trochlear groove and the midlateral weight-bearing portion of the lateral femoral condyle. 15, No. We use cookies on our website to give you the most relevant experience by remembering your preferences and repeat visits. Epidemiology. Coronoid process fractures may be diagnosed on a plain film series of the elbow, generally on a lateral or a 45 internal oblique view 4. This also corresponds to our study with only 4 out of 30 cases (13.3%) of age more than 30 years. 45, No. Le N, Blackman B, Zakharia A, Cohen D, de Sa D. Knee Surg Sports Traumatol Arthrosc. The final study group was composed of these 10 patients (male:female ratio, 7:3; age range, 15-22 years; mean age, 18 years). 35, No. This view is only necessary if the standard views are normal and a patellar fracture is still suspected, or to assess patellar dislocation. Chen J, Ye Z, Wu C, Zhang X, Zhao J, Xie G. Knee Surg Sports Traumatol Arthrosc. Trochlear facet asymmetry was characterized by a ratio which measured <40% and it indicated dysplasia [Figures 3 and 4]. Terminology. 51, No. Radiology report. First episode of dislocation at a younger age group has constantly been recognized as a major risk factor for recurrent LPD in majority of studies. Looser zones are also a type of insufficiency fracture. Classification. Twenty-one (70%) and 27 (90%) cases were positive for decreased trochlear depth when measured at the level of trochlear bone and cartilage, respectively. 6, Journal of Manipulative and Physiological Therapeutics, Vol. Get an accredited certificate of achievement by completing one of our online course completion assessments. Radiology report. MRI of the Thumb: Anatomy and Spectrum of Findings in Asymptomatic Volunteers, Review. eCollection 2022. 1, Arthroscopy: The Journal of Arthroscopic & Related Surgery, Vol. WebRadiopaedia.org, the wiki-based collaborative Radiology resource Based on the known mechanism of injury and on the location and pattern of osteochondral injuries and marrow contusions recorded in our Results section, we propose the following mechanism of injury regarding lateral femoral condyle osteochondral injuries. 10, The American Journal of Sports Medicine, Vol. HHS Vulnerability Disclosure, Help 3). Translate this page into: Osteochondral defects located anterior to the anterior margin of the anterior horn of the lateral meniscus were designated as involving the articular surface of the trochlear groove. 41, No. 273, No. 2 Baldwin JL. Clipboard, Search History, and several other advanced features are temporarily unavailable. Treatment can be conservative in acute phase or, if recurrent dislocation, require surgical correction of bone defects or ligament injury [1]. MRI of Osteochondral Defects of the Lateral Femoral Condyle: Incidence and Pattern of Injury After Transient Lateral Dislocation of the Patella, Review. Imaging of Anterior Cruciate Ligament Repair and Its Complications, Pictorial Essay. Limitations of this study include the small sample size. Twelve out of 30 cases (40 %) were positive for patella alta in our study. These cookies help provide information on metrics the number of visitors, bounce rate, traffic source, etc. 8, BMC Sports Science, Medicine and Rehabilitation, Vol. 6, The Physician and Sportsmedicine, Vol. The depth of the lateral femoral notch sign has been shown to correlate with anterior cruciate ligament (ACL) tear 2. Sagittal knee radiograph may show patella alta, crossing sign or a trochlear bump. Please see separate articles for discussion of medial and lateral patellar dislocations. This is in discordance with the study done by Carrillon et al. 11, Journal de Traumatologie du Sport, Vol. 11, Journal of Clinical Orthopaedics and Trauma, Vol. You also have the option to opt-out of these cookies. In this study, we have used three different parameters to assess trochlear dysplasia, namely, trochlear depth, lateral trochlear inclination, and trochlear facet ratio. PMC The angle between these two lines is the lateral trochlear inclination. Strictly speaking, a torus fracture refers to a circumferential buckle fracture 7.However, the terms are often used interchangeably. 10, Journal of Orthopaedic Surgery and Research, Vol. WebImaging and Radiology; Internal Medicine; Lab Services; Mental and Behavioral Health; Obstetrics and Gynecology Lateral epicondylitis/"Tennis elbow" Learn More. vol.19 no.1 So Paulo 2011. 15, No. Radiology Masterclass, Department of Radiology, The chondral injury is consistently located at the posterior margin of the nonarticular marrow edema (Figs. 38, No. [20] in their study established a statistically significant odds ratio for recurrence of patellar dislocation, when the first episode of dislocation was at an age <16 years in comparison to a later onset of the first episode. Anomalies of dynamic and static factors, including excessive patellar height, tibial tubercle lateralisation or trochlear dysplasia, may influence the development of the patella. Clin Orthop Relat Res. 1, Arthroscopy: The Journal of Arthroscopic & Related Surgery, Vol. Trochlear depth and trochlear facet asymmetry were measured both at the level of trochlear cartilage (in accordance with Escala et al. 12, Medicine & Science in Sports & Exercise, Vol. 33, No. With flexion at knee joint, patella articulates with trochlea at approximate 10 of flexion.[10-13]. All courses are CME/CPD accredited in accordance with the CPD scheme of the Royal College of Radiologists - London - UK. WebLateral patellar dislocation is a common clinical entity with a characteristic MR appearance. 48, No. Although it appears Lateral radiograph revealing high patella, suprapatellar recess joint effusion and soft tissue swelling, with no evidence of patellar fracture. After the injury, the patient usually seeks medical attention because of persistent pain and swelling, which is typically located along the medial joint line, and the patient occasionally complains of a locking or catching sensation. [15] where a specificity and sensitivity of 96% and 100%, respectively, were established for both trochlear facet asymmetry and trochlear depth as a diagnostic tool for patellar instability. As we move distally, the TG deepens, so the chances of patellar dislocation are less likely in distal trochlea. 40, No. A significant number of osteochondral injuries involve the midlateral weight-bearing portion of the lateral femoral condyle and are more posterior than would be expected after transient dislocation of the patella. 11, Orthopedic Clinics of North America, Vol. Summary. Our results highlight that the most critical factor responsible for patellar instability is trochlear dysplasia. Patellar dislocation is a common condition accounting for 23% of knee injuries [15, 29].Nearly 40% of patients with patellar dislocation experience recurrence after nonoperative treatment; [], and almost 50% of patients with recurrent patellar dislocation (RPD) require surgical intervention to regain stability [].Risk factors for RPD have been clarified to be WebNormal limits of knee range of motion include extension from 0 to 10 and flexion to 135. All radiologists must keep in mind all the risk factors for patellar instability measurable on MRI and should document them in their reports so that the appropriate treatment can be selected. FOIA Forty-eight percent (39 of 82) showed more than one site of injury to the medial stabilizers; 45% (37 of 82) showed edema or hemorrhage at the inferior VMO. The medial and lateral collateral ligaments are normal, as is the iliotibial tract, biceps femoris, popliteus tendon, and common peroneal nerve. Tuberculosis or Not Tuberculosis: Temporal Evolution of, The Role of Diffusion-weighted Magnetic Resonance Imaging in, Evaluation of Occult Femoral Neck Fractures Computed, Trochlear facet asymmetry at cartilage level. articulation: ball and socket joint between the head of the femur and the acetabulum ligaments: ischiofemoral, iliofemoral, pubofemoral and transverse acetabular ligaments, and the ligamentum teres 1 movements: thigh flexion and extension, adduction and abduction, internal and external rotation blood supply: branches of the medial and lateral Department of Radiology, Centro Hospitalar Universitrio Lisboa Central/ Lisboa 2019, Ana Lusa Proena, Department of Radiology, Centro Hospitalar Universitrio Lisboa Central/ Lisboa 2019, Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Out of these, the cookies that are categorized as necessary are stored on your browser as they are essential for the working of basic functionalities of the website. This could in part be related to the skill of the arthroscopist or could possibly be explained by the fact that what appeared to be an osteochondral defect on MRI was merely volume averaging with adjacent soft-tissue structures because these defects were often observed at the far lateral aspect of either the trochlear groove or the weight-bearing aspect of the lateral femoral condyle. 10, Orthopaedic Journal of Sports Medicine, Vol. 5, 2022 Radiological Society of North America, Acute Lateral Patellar Dislocation at MR Imaging: Injury Patterns of Medial Patellar Soft-Tissue Restraints and Osteochondral Injuries of the Inferomedial Patella, https://doi.org/10.1148/radiol.2253011578, Layered Approach to the Anterior Knee: Normal Anatomy and Disorders Associated with Anterior Knee Pain, Imaging Characteristics of Contralateral Asymptomatic Patellofemoral Joints in Patients with Unilateral Instability, MR Imaging of Patellar Instability: Injury Patterns and Assessment of Risk Factors1. Epub 2017 May 2. 19, No. It can occur in a variety of settings, including: trauma; osteoporosis; Langerhans Mandibular fractures are relatively common especially among young men. ISBN-13: 978-0323374620, [2] 25, No. 4, No. 1, Orthopaedics & Traumatology: Surgery & Research, Vol. Published by Scientific Scholar on behalf of Musculoskeletal Society (MSS), India, 2021 Published by Scientific Scholar on behalf of Indian Journal of Musculoskeletal Radiology. By clicking Accept, you consent to the use of ALL the cookies. Recurrent patellofemoral dislocation due to patellofemoral instability, Brought to you by the European Society of Radiology (ESR) -. 101, No. The .gov means its official. Unable to load your collection due to an error, Unable to load your delegates due to an error. 4), decreased lateral trochlear inclination (<11) and Dejour classification is used to describe trochlear morphology (Fig. During reduction, the articular surface of the medial aspect of the lower pole of the patella first impacts the nonarticular portion of the lateral femoral condyle, resulting in the classic bone contusion. This report does not attempt to determine the frequency of this injury but simply describes the arthroscopic findings in seven patients [8]. That said, there were still six chondral defects confirmed by the arthroscopist, making this an important injury to be aware of. Patellar translation is measured by TT-GT distance (tibial tubercle to trochlear groove), being abnormal above 20mm (Fig. 11, Knee Surgery, Sports Traumatology, Arthroscopy, Vol. Notice the dysplastic trochlea, with a shallow sulcus angle and a hypoplastic medial condyle. The most important differential diagnosis is that of a lunate dislocation which can mimic a perilunate dislocation, especially on AP projection. 8, Clinics in Sports Medicine, Vol. These three lines were drawn such that they depict maximum anteroposterior distance of medial and lateral trochlear facets (Line C and A) and the deepest sulcal point (Line B). 26, No. Although these lesions can occur in the region of the lateral trochlear groove as previously reported in the radiology literature, it is actually more common for this lesion to occur in the midlateral weight-bearing aspect of the lateral femoral condyle at the posterior margin of the lateral femoral condyle bone contusion. 37, No. This proved to be a highly predictable pattern of injury and was observed in each of the 10 cases. Injury. CONCLUSION. During the second phase of the injury, the patella reduces to its normal position within the trochlear groove. 1). 1, Revista Espaola de Ciruga Ortopdica y Traumatologa (English Edition), Vol. 10, Indian Journal of Orthopaedics, Vol. Radiology 1993; 189:905-907. 8, Clinics in Sports Medicine, Vol. Terms and Conditions .switcher {font-family:Arial;font-size:10pt;text-align:left;cursor:pointer;overflow:hidden;width:163px;line-height:17px;} 8600 Rockville Pike 2, Clinics in Sports Medicine, Vol. Soft-tissue fixation is not inferior to suture-anchor fixation in reconstruction of the medial patellofemoral ligament using a nonresorbable suture tape. 3, Knee Surgery, Sports Traumatology, Arthroscopy, Vol. Contact us. 9, No. The following parameters were used to evaluate trochlear dysplasia: To calculate lateral trochlear inclination two lines were drawn, one along the subchondral bone of lateral trochlear facet and other along the posterior aspect of condyles of femur. 6, Clinical Orthopaedics and Related Research, Vol. 1, Knee Surgery, Sports Traumatology, Arthroscopy, Vol. Chondral defects overlapping the anterior margin of the anterior horn of the lateral meniscus were considered to be involving both chondral surfaces. Take home lessons: PFI predisposes to recurrent patellar dislocation. 40, No. In our study, we found that both these factors show statistically significant improvement in results when measured along trochlear cartilage as compared to trochlear bone (P = 0.001). MATERIALS AND METHODS: Knee MR images obtained within 8 weeks after LPD were evaluated for medial retinacular and medial patellofemoral ligament (MPFL) disruption, vastus medialis obliquus (VMO) edema and/or elevation, and other derangements. This corresponds to our study in which 93.3% had at least two of the five risk factors of patellar instability.[19]. Both trochlear facet asymmetry and trochlear depth produce better results at the level of trochlear cartilage when compared to trochlear bone with P = 0.001 [Table 4 and Graph 2]. 41, No. 44, No. The 25 cases were retrospectively reviewed in consensus by two musculoskeletal radiologists who had 7 and 18 years, respectively, of clinical experience in musculoskeletal radiology. 4, The Journal of Bone and Joint Surgery-American Volume, Vol. The injury mostly occurs due to twisting of knee when knee is in mild flexion (<30) which leads to injury of medial stabilizers and medial aspect of patella strikes against lateral femoral condyle. A normal sulcus is located within 10 mm of Blumensaat's line on lateral projection 3. Knee - Patellar fracture - AP. High-grade osteochondral injuries involving the patella or the lateral femoral condyle are often treated with abrasion chondroplasty or autologous chondrocyte transplantation, and treatment of these lesions has been shown to improve functional outcome in adolescent athletes [14]. Injury patterns of medial patellofemoral ligament and correlation analysis with articular cartilage lesions of the lateral femoral condyle after acute lateral patellar dislocation in adults: An MRI evaluation. 12, EMC - Tecniche Chirurgiche - Chirurgia Ortopedica, Vol. 2, Revista Brasileira de Ortopedia (English Edition), Vol. Christensen TC, Sanders TL, Pareek A, Mohan R, Dahm DL, Krych AJ. [10] and Pfirrmann et al.[15]). 3, Knee Surgery, Sports Traumatology, Arthroscopy, Vol. Dynamic tracking influenced by anatomy in patellar instability. 2, Archives of Orthopaedic and Trauma Surgery, Vol. Epidemiology. 11, Revue du Rhumatisme Monographies, Vol. 07, Orthopaedic Journal of Sports Medicine, Vol. Careers. Quality of life following medial patellofemoral ligament reconstruction combined with medial tibial tubercle transfer in patients with recurrent patellar dislocation: a retrospective comparative study. Medial retinacular complex injury in acute patellar dislocation: MR findings and surgical implications. 203, No. In two of the patients, the surgeon reported no evidence of femoral chondral injury. 23, No. Twelve cases (40 %) were positive for patella alta. MR Imaging of Patellar Instability: Injury Patterns and Assessment of risk Factors. [4] Waldt S, Woertler K. Measurements and Classifications in Musculoskeletal Radiology. MRI is the most complete technique, allowing not only morphologic evaluation of trochlea and patella, but also evaluation of ligaments, osseous contusions and osteochondral lesions [5]. 2018 Mar;26(3):719-726. doi: 10.1007/s00167-016-4408-3. 1, The Egyptian Orthopaedic Journal, Vol. evaluated 103 patients with age <14 years for dysplastic trochlea, TT to TG distance, patellar tilt, and patella alta on MRI. More recently, there has been brief mention in both the radiology and orthopedic literature of osteochondral injuries involving not only the patellar articular surface but also the articular surface of the lateral femoral condyle [6-10]. Disclaimer, National Library of Medicine 2002;225: 736-43. One hundred patients with no evidence of prior LPD were evaluated as controls. 455, Sports Medicine and Arthroscopy Review, Vol. 37, No. Dislocations should not be confused with Subluxation. 11, Revista Brasileira de Ortopedia (English Edition), Vol. Zhang GY, Zheng L, Shi H, Qu SH, Ding HY. Knee - Patellar fracture - AP. The typical MRI findings after transient lateral dislocation of the patella have been well described and include a bone contusion pattern involving the inferomedial pole of the patella and the anterolateral aspect of the nonarticular portion of the lateral femoral condyle. An elongated lateral tubercle of the posterior process of the talus is referred to as a Stieda process, so occasionally these fractures are described as Stieda process fractures.. A Cedell fracture is a fracture of the medial tubercle of the posterior .switcher .selected {background:#fff linear-gradient(180deg, #efefef 0%, #fff 70%);position:relative;z-index:9999;} Various sequences used in our study included T1-weighted Turbo spin echo sagittal, fat-suppressed proton-density sagittal and axial (FSPD SAG and AXIAL), and gradient-echo fast-field echo coronal. Not infrequently the formation of a lipohaemarthrosis is the only radiological sign. 7, Journal of Orthopaedic Surgery and Research, Vol. MRI also allows evaluation of ligaments and osteochondral lesions. It is likely therefore that the lateral femoral condyle osteochondral injuries result from a shearing force that occurs during the first stage of injury. Would you like email updates of new search results? Next, the images were evaluated for the presence of an osteochondral injury or defect involving the lateral femoral condyle, and if present, the osteochondral defect was graded according to a modified Outerbridge classification system [5]: grade 1, chondral softening or blistering with an otherwise intact surface; grade 2, shallow superficial fissuring or ulceration involving less than 50% of the depth of the articular surface; grade 3, deep ulceration, fissure, or flap that involved more than 50% of the depth of the articular cartilage without exposure of subchondral bone; grade 4, full-thickness chondral defect with exposure of subchondral bone; and grade 5, full-thickness chondral abnormalities with underlying cortical defect. 1, No. Lateral dislocation of patella is prevented by various medial stabilizers, among which most important role is played by medial patellar retinaculum/medial patellofemoral ligament (MR/MPFL). 6, Journal of Pediatric Orthopaedics, Vol. 2006 Mar;13(2):145-50 Am J Sports Med. The most common location of patella dislocations is lateral dislocation. Lateral patellar dislocation refers to lateral displacement followed by dislocation of the patella due to disruptive changes to the medial patellar retinaculum. Transient lateral patellar dislocation: diagnosis with MR imaging. 46, No. In summary, our results suggest that after transient lateral dislocation of the patella, osteochondral injuries of the lateral femoral condyle occur more commonly than has been previously reported in the MR literature. Osteochondral defects of the lateral femoral condyle are a common sequela after transient lateral patellar dislocation. 1, Korean Journal of Radiology, Vol. eCollection 2022 Sep 20. A new factor predicting excessive femoral anteversion in patients with recurrent patellar dislocation. 5, No. It is also possible that a chondral defect was present but not considered by the surgeon to be significant enough to warrant treatment or mention in the operative report. 28, No. 27, No. A systematic radiological approach should be followed for the patient, right from the selection of the highest transverse section showing trochlear cartilage for the evaluation of various risk factors to the corrective placement of calipers for measuring parameters. Lateral Femoral Condyle CRATER sign of BRIK an Ancillary Sign of Lateral Patellar Dislocation. Another strength of our study was the criteria used for deciding the level at which various measurements for diagnosis of patellar instability were performed. The distance between two lines was given as TT-TG distance. Patellar height ratio and TT-TG showed relatively less contribution for unstable patella. 30, No. The MPFL femoral origin was identified in 87% (71 of 82); of these, 49% (35 of 71) showed injury. One hundred and five patients (140 knees) with objective patellar instability were retrospectively reviewed to identify a possible association between the above-mentioned predisposing factors and patellar shape. It is more common in young females in the second decade of life due to ligament laxity [1]. 29, No. 32, No. Zhang GY, Zheng L, Feng Y, Shi H, Liu W, Ji BJ, Sun BS, Ding HY. Dejour classification for trochlear dysplasia : Type A normal shape but shallow angle, Type B Flattening of the normal trochlear concavity or slight convexity, Type C facets assimetry, with medial facet hypoplasia, Type D Similar to type C but with a bone protrusion (cliff pattern). 95, No. 10, No. Thirty patients of patellar instability were assessed on MRI for risk factors of patellar instability including trochlear dysplasia, tibial tuberosity to trochlear groove (TT-TG) distance, and patellar height ratio. official website and that any information you provide is encrypted Evid Based Complement Alternat Med. 6, No. 2008 Dec;16(12):1068-79 1, The American Journal of Sports Medicine, Vol. Other examination findings in LPDs included contusions of the lateral femoral condyle (66 [80%] of 82 examinations) or medial patella (50 [61%] of 82), intraarticular bodies (12 [15%] of 82), effusion (45 [55%] of 82), medial collateral injury (nine [11%] of 82), and meniscal tear (nine [11%] of 82). 3, The American Journal of Sports Medicine, Vol. Distance between S and P is measured. 15, No. Anatomic shape of the trochlea predisposes to lateral dislocation of patella, that is held in place by active stabilisers (extensor muscles) and passive stabilisers, which include bone morphology (patellar, trochlear and condyle shape) and ligaments (medial retinaculum, patellar tendon and, most important, medial patellofemoral ligament(MPFL)) [2]. 1, The American Journal of Sports Medicine, Vol. 2, Operative Techniques in Sports Medicine, Vol. Transverse dimensions were obtained from the coronal images, whereas anteroposterior dimensions were obtained from the sagittal images. 22, No. Repeat dislocations can lead to further bony defects in both the humeral head and glenoid and the engaging HillSachs defect is associated with decreased glenoid bone stock, glenoid rim fracture, and chronic instability 14. 1997 Jan;168(1):117-22. doi: 10.2214/ajr.168.1.8976933. 4, Operative Techniques in Sports Medicine, Vol. 2022 Dec 4. doi: 10.1007/s00167-022-07245-3. The patient usually falls to the ground in pain, at which time the patella reduces spontaneously. Terminology. [1] also described a very low incidence of patellar instability in more than 30 years of age. 47, No. In each case, the subchondral marrow edema was centered anterior to the chondral defect, with the chondral defect located along the posterior margin of the subchondral edema (Figs. Typically, Monteggia fracture-dislocations occur as the result of a fall onto an outstretched hand (FOOSH) 4.. Transient dislocation of the patella occurs in two separate stages. 11, BMC Musculoskeletal Disorders, Vol. thickening of the distal patellar tendon; infrapatellar bursitis; MRI. Twenty-eight (93.7%) out of 30 cases showed more than 1 risk factors (multifactorial) for patellar instability, out of which 12 patients (40%) had two risk factors, 9 patients (30%) had three risk factors, 5 patients (16.6%) had four risk factors, and 2 patients (6.7%) had all the five risk factors [Table 3]. 6, The American Journal of Sports Medicine, Vol. Patients often complain of anteromedial knee pain which is attributed to MR/MPFL injury and osseous/chondral injury (involving medial aspect of patella and lateral aspect of femoral condyle). Patella baja, also known as patella infera, is an abnormally low lying patella, which is associated with restricted range of motion, crepitations, and retropatellar pain.If longstanding, extensor dysfunction may ensue with significant morbidity. An 8-year-old female patient presented with a spontaneous patellar dislocation that was manually reduced by paramedics. Tsuda E, Ishibashi Y, Yamamoto Y, Maeda S. Knee Surg Sports Traumatol Arthrosc. If only those patients with injuries isolated to the lateral trochlear groove are included, the incidence in our series is 12%, which is more in line with the 5% incidence reported by Elias et al. AJR Am J Roentgenol. RESULTS: Signal intensity Some authors suggest a better detection rate with 20 tilted or internal oblique radiographs 6,9. Arthroscopy confirmed the presence of chondral defects of the lateral femoral condyle in six (75%) of the eight cases. Patients typically present with obvious deformity and an inability to extend the knee. The reports were reviewed for evidence of prior lateral patellar dislocation. To assess magnetic resonance (MR) imaging findings after acute lateral patellar dislocation (LPD) with emphasis on the medial patella restraints and to describe a medial patellar impaction deformity. In trochlear dysplasia, there is diminished engagement between femoral trochlea and patella due to a shallow TG, thereby leading to patellar instability. Patellar instability is more prevalent in females than males. 9, No. Sonography on injury of the medial patellofemoral ligament after acute traumatic lateral patellar dislocation: Injury patterns and correlation analysis with injury of articular cartilage of the inferomedial patella. Enter your email address below and we will send you the reset instructions. Twenty-four cases (80%) were of age equal to or <25 years. Results: 141, No. The Student t test was used for statistical comparisons. 1, Orthopaedics & Traumatology: Surgery & Research, Vol. 90, No. 2022 Jul 28;17(1):366. doi: 10.1186/s13018-022-03259-2. Operative reports were obtained on all patients who underwent follow-up arthroscopy. MRI of Spinal Bone Marrow: Part 2, T1-Weighted Imaging-Based Differential Diagnosis, Review. The Bado classification is used to subdivide the fracture-dislocation into four types which all have different treatment options and prognoses and is based on the principle that the direction in which the apex of the ulnar fracture 1A, 1B, 1C, 2A, 2B, and 2C). 32, No. Acute patellar dislocation can be spontaneous or traumatic and if risk factors are present can become chronic and lead to patellofemoral osteoarthrosis. Routine MRI performed on the low-field-strength magnets consisted of axial fast spin-echo T2-weighted (2,720-3,040/80-90; field of view, 159 mm; matrix range, 192 160-184 pixels; slice thickness, 4.0-5.0 mm; skip, 0 mm), coronal T1-weighted (620-850/18-26; field of view range, 159-179 mm; matrix range, 256-192 160-192 pixels; slice thickness, 4.0-5.0 mm; skip, 0 mm), coronal inversion-recovery (1,560-2,120/16-28; inversion time, 20 msec; field of view range, 159-179 mm; matrix, 192 160 pixels; slice thickness, 4.0-6.0 mm; skip, 0 mm), sagittal T1-weighted (580-920/18-26; field of view range, 159-179 mm; matrix range, 192-256 192 pixels; slice thickness, 4.0-4.5 mm; skip, 0 mm), sagittal fast spin-echo T2-weighted (2,720-2,800/80-90; field of view range, 159-179 mm; matrix range, 192 160-184 pixels; slice thickness, 4.0-4.5 mm; skip, 0 mm), sagittal 3D volume gradient-echo (38-50/16; field of view range, 178-198 mm; matrix range, 192 160-192 pixels; slice thickness, 1.7-3.5 mm; skip, 0 mm) sequences. In one of the study, patella alta was present in 36% of subjects in control group, therefore, patella alta holds higher utility as a risk factor in patellar instability when it is present along with other risk factors such as increased TT-TG distance and dysplastic trochlea. The role of this study was to recognize the predisposing factors of patellar instability on MRI. Epub 2016 Feb 26. 2, Current Physical Medicine and Rehabilitation Reports, Vol. Patellar shift ratio (PSR) is the optimal measurement for characterising lateral patellar shift and a reliable predictor of recurrent patellardislocation. 89-B, No. 2, The Journal of Bone and Joint Surgery. Furthermore, in our study, female patients predominated (56.7%) over male (43.3%), which clearly corresponds to available literature. The Patellar is the largest sesamoid bone in the body, and it resides within the complex of the quadriceps and patellar tendons. 28, No. 7, International Orthopaedics, Vol. These cookies track visitors across websites and collect information to provide customized ads. 1, American Journal of Roentgenology, Vol. 12, LO SCALPELLO-OTODI Educational, Vol. 11, EMC - Techniques chirurgicales - Orthopdie - Traumatologie, Vol. 38, No. Page author: Increased lateral stresses may produce a Wiberg type C patella, with a hypoplastic medial facet and a more developed lateral facet. PURPOSE: To assess magnetic resonance (MR) imaging findings after acute lateral patellar dislocation (LPD) with emphasis on the medial patella restraints and to describe a medial patellar impaction deformity. 4, BMC Musculoskeletal Disorders, Vol. 1977;63 Suppl 2:62-8 The use of low-field-strength magnets may have actually resulted in underdetection of these lesions. 3, Medial meniscus, anterior horn. Lateral dislocation of patella is common due to the divergent pull of the patellar tendons and quadriceps, which is further aggravated by the normal rest state valgus configuration of knee. Elias JJ, Soehnlen NT, Guseila LM, Cosgarea AJ. 3, EMC - Tcnicas Quirrgicas - Ortopedia y Traumatologa, Vol. document.write(theYear) | Subluxation is when the joint is still partially attached to the bone.. Ten cases (33.33%) were positive for decreased lateral trochlear inclination. Radiological evaluation of patellofemoral instability and possible causes of assessment errors: Letter to the editor. 34, No. 2015 Dec;46(12):2413-21. doi: 10.1016/j.injury.2015.09.025. Conclusion: AJR Am J Roentgenol 1993; 161:109-113. On plain film, dorsal avulsion injuries are best detected on a lateral projection, where typically an avulsed flake of bone is identified lying posteriorly to the triquetral bone (see pooping duck sign). .switcher .option::-webkit-scrollbar {width:5px;} Carrillon et al. Mean VMO elevation in the coronal plane of the adductor tendon was 2.2 cm, with a range of 0.64.5 cm (in control subjects, 0.9 cm; range, 0.12.5 cm; P < .001). This category only includes cookies that ensures basic functionalities and security features of the website. P Perpendicular line to A to the posterior patellar apex. Because the diagnosis of lateral patellar dislocation is often unsuspected, MR provides valuable diagnostic information in such cases. These cookies will be stored in your browser only with your consent. The fact that the patella is at risk for a shearing or impaction injury or both during both dislocation and reduction but the femoral articular surface is at risk only during dislocation is likely the reason for the higher incidence of articular cartilage lesions involving the patella [6] (Figs. 1, Patellar tendon. An official website of the United States government. Draw a line tangential to femoral condyle (green line). Seven cases (23.3%) had increased TT to TG distance. 1, Revista Chilena de Ortopedia y Traumatologa, Clinical Journal of Sport Medicine, Vol. .switcher a img {vertical-align:middle;display:inline;border:0;padding:0;margin:0;opacity:0.8;} [1,2] Lewallen et al. Copyright 2013-2020, American Roentgen Ray Society, ARRS, All Rights Reserved. MRI plays an important role to identify various risk factors for patellar instability which includes trochlear dysplasia, high-riding patella (patella alta), and abnormal TT-TG distance. Accessibility -, Knee. 2022. Anterior glenohumeral dislocation will lead to impaction of the posterolateral humeral head and anterior glenoid rim. Early reports of MRI findings after transient dislocation of the patella described chondral defects of the patella but made no mention of chondral injuries of the lateral femoral condyle [1-5]. Baker cysts, or popliteal cysts, are fluid-filled distended synovial-lined lesions arising in the popliteal fossa between the medial head of the gastrocnemius and the semimembranosus tendons via a communication with the knee joint.They are usually located at or below the joint line. 10, International Orthopaedics, Vol. This work is licensed under aCreative Commons Attribution-NonCommercial-ShareAlike 4.0 International License. Purpose: To assess magnetic resonance (MR) imaging findings after acute lateral patellar dislocation (LPD) with emphasis on the medial patella restraints and to describe a medial patellar impaction deformity. The Frykman classification of distal radial fractures is based on the AP appearance and encompasses the eponymous entities of Colles fracture, Smith fracture, Barton fracture, chauffeur fracture.. J Orthop Surg Res. 3, The American Journal of Sports Medicine, Vol. 2008 May;29(5):359-65. doi: 10.1055/s-2007-965360. 6, European Journal of Radiology, Vol. Subchondral marrow edema was present underlying the chondral defects in 10 (100%) patients. MRI: Magnetic resonance imaging, TT-TG: Tibial tubercle-trochlear groove. These MRI examinations were performed at six different outpatient imaging facilities. Fithian et al. Tarsometatarsal dislocation may also occur in the diabetic neuropathic joint . Please enable it to take advantage of the complete set of features! Transient lateral patellar dislocation is a common injury that typically occurs in the young, athletic individual. The Insall-Salvati ratio was initially determined on a 30 flexed lateral knee x-ray and was later applied to sagittal MRI. [10] also described the use of these three parameters in the assessment of trochlear dysplasia with excellent values in discriminating cases and controls. Out of three parameters that define trochlear dysplasia, shallow trochlear depth was found to be strongest determinant responsible for patellar instability followed by trochlear facet asymmetry and lateral trochlear inclination. CT or MR may be more sensitive than conventional radiographs for detection of avulsion injuries. 11, Arthroscopy: The Journal of Arthroscopic & Related Surgery, Vol. 04, Orthopaedic Journal of Sports Medicine, Vol. 41, No. 3, Magnetic Resonance Imaging Clinics of North America, Vol. 2022 Nov 13. doi: 10.1007/s00167-022-07222-w. Online ahead of print. Azar FM, Canale ST, Beaty JH. A partial dislocation is referred to as a subluxation.Dislocations are often caused by sudden trauma on the joint like an impact or fall. MRI, as expected, is more sensitive and specific, and will demonstrate: soft-tissue swelling anterior to the tibial tuberosity; loss of the sharp inferior angle of the infrapatellar fat pad (Hoffa fat pad) thickening and oedema of the distal patellar tendon 5, Knee Surgery, Sports Traumatology, Arthroscopy, Vol. We also use third-party cookies that help us analyze and understand how you use this website. 1, Indian Journal of Musculoskeletal Radiology, Vol. There is no mention in this report of osteochondral injuries involving the weight-bearing aspect of the lateral femoral condyle. This study received clearance from the Ethics Review Committee. Trochlear dysplasia can involve a shallow, flattened or convex trochlear groove +/- a hypoplastic (small) or convex lateral femoral condyle 15. Consequently, our objective was to determine the incidence of lateral femoral condyle osteochondral injuries and to better define the locations and patterns of chondral injury involving the lateral femoral condyle after transient dislocation of the patella based on MRI and follow-up arthroscopy. Thirty patients with clinical suspicion and MRI findings of patellar instability were enrolled in this single institutional observational study. 33, No. 38, No. 4, Knee Surgery, Sports Traumatology, Arthroscopy, Vol. 3, Russian Pediatric Journal, Vol. [3,4] Mostly lateral patellar dislocations (LPDs) are transient in nature with very few cases presenting with fixed lateral dislocation. 12, Journal of Orthopaedic Surgery and Research, Vol. Purpose: 20, No. 6, Archives of Trauma Research, Vol. 38, No. 3, No. Patellar instability is a spectrum of conditions ranging from intermittent subluxations to dislocation. There may be depression of the plateau surface, displacement of a fracture fragment, or a combination of both. 7, The American Journal of Sports Medicine, Vol. 6). 98, No. The cutoff for trochlear dysplasia was an inclination angle of <11 [Figure 2]. 1, Revue de Chirurgie Orthopdique et Traumatologique, Vol. At the inferomedial patella, 70% (57 of 82) of LPD examinations showed osteochondral injury and 44% (36 of 82) showed concave impaction deformity (0 of 100 control subjects). Each of the original interpretations was performed by one of four experienced, fellowship-trained musculoskeletal radiologists. 5, Techniques in Knee Surgery, Vol. The site is secure. Fractures of the patella may only be visible on 1 of the 2 standard views, more often the lateral view. In the context of trauma the Lateral view is acquired with the patient lying supine and with a horizontal X-ray beam. Increased TT-TG pertains to laterally placed TT in relation to TG which leads to increased lateral pull of patellar tendon over patella leading to increased risk of lateral dislocation. One hundred patients with no evidence of prior LPD were evaluated as controls. In addition, two of the patients have not undergone follow-up surgery. Eighty-two examinations were performed in 81 patients with LPD (mean age, 20 years; age range, 9-57 years). 27, No. Potential soft-tissue injuries include a partial- or full-thickness tear of the medial soft-tissue restraints, including the medial patellofemoral ligament and medial retinaculum [7, 11, 12]. The MR images of these 25 patients were then reviewed and 10 patients were found to have osteochondral defects involving the lateral femoral condyle. 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