MRI of the Morel-Lavallée lesion - a case series.

INTRODUCTION: The aim of the study was to review the appearances of Morel-Lavallée (ML) lesions on magnetic resonance imaging (MRI). PATIENTS AND METHODS: 14 patients diagnosed with the ML lesion on MRI were analysed retrospectively (mean age = 35 years). Mechanism of injury, time frame from injury to MRI, location, shape, T1 and proton-density fat-suppression (PDFS) signal intensity (SI), presence of a (pseudo)capsule, septations or nodules within the collection, mass effect and fluid-fluid levels were analyzed. The Mellado and Bencardino classification was utilized to classify the lesions. RESULTS: In most cases, mechanism of injury was distortion. Mean time frame between the injury and MRI was 17 days. Lesions were located around the knee in 9 patients and in the peritrochanteric region in 5 patients. Collections were fusiform in 12 patients and oval in 2 patients. 9 collections were T1 hypointense and PDFS hyperintense. 4 collections had intermediate T1 and high PDFS SI. 1 collection had intermediate T1 and PDFS SI. (Pseudo)capsule was noted in 3 cases. Septations or nodules were found in 4 cases. According to the Mellado and Bencardino, collections were classified as seroma (type 1) in 9, subacute hematoma (type 2) in 1 and chronic organizing hematoma (type 3) in 4 cases. CONCLUSIONS: Characteristic features of ML lesion include a fusiform fluid collection between the subcutaneous fat and the underlying fascia after shearing injury. Six types can be differentiated on MRI, with the seroma, the subacute hematoma and the chronic organizing hematoma being the commonest.

Características moleculares y microanatómicas de la grasa y su aplicación en el tratamiento de quemaduras agudas y secuelas / Molecular and microanatomic characteristics of fat and its application in the treatment of acute burns and sequelae

INTRODUCCIÓN Y OBJETIVO: Durante los últimos 20 años, el tejido adiposo ha sido reconocido universalmente como algo más que solo un depósito de energía y ahora se sabe que la grasa es un tejido que tiene funciones endocrinas, paracrinas y autocrinas, capaz de sintetizar y secretar varias citocinas de señalización llamadas adipocinas, en además de hormonas, pro hormonas, enzimas y material genético. Este artículo tiene como objetivo analizar la biología molecular, la microanatomía, la comunicación intercelular y el potencial regenerativo del tejido adiposo, presentando la experiencia del autor en el uso de grasa para tratar lesiones producidas por quemaduras en diversas fases, profundidades y regiones anatómicas. MATERIAL Y MÉTODO: Estudio realizado en varios pacientes que sufrieron quemaduras térmicas, eléctricas y químicas, agudas y tardías, tratados en la Unidad de Tratamiento de Quemaduras de la Clinica Sáo Vicente en Rio de Janeiro, Brasil. Abordamos las técnicas de aplicación tópica e inyección de grasa, según los tipos de quemaduras o secuelas. RESULTADOS: Presentamos los resultados obtenidos con esta técnica a corto y largo plazo. CONCLUSIONES: La preservación de la actividad metabólica del tejido adiposo aspirado es muy importante para lograr el resultado regenerativo esperado

BACKGROUND AND OBJECTIVE: During the past 20 years, adipose tissue has been universally recognized as more than just an energy deposit and it is now known that fat is a tissue that has endocrine, paracrine and autocrine functions, capable of synthesizing and secreting several signaling cytokines called adipokines, in addition to hormones, pro hormones, enzymes and genetic material. This article aims to analyze molecular biology, microana-tomy, intercellular communication and the regenerative potential of adipose tissue, presenting the author's experience in the use of fat to treat lesions caused by burns in various phases, depths and anatomical regions. METHODS: Study conducted in several patients who suffered thermal, electrical and chemical burns, both acute and late, treated in a Burn Treatment Unit. Topical application and fat injection techniques are addressed, depending on the types of burns or sequelae. RESULTS: The results obtained with this technique in several cases of short- and long-term burns are presented, demonstrating the effectiveness of this new modality of treatment. CONCLUSIONS: Preservation of the metabolic activity of the aspirated adipose tissue is very important to achieve the expected regenerative result

Extra-cellular matrix rigidity may dictate the fate of injury outcome.

After injury, while regeneration can be observed in hydra, planaria and some vertebrates, regeneration is rare in mammals and particularly in humans. In this paper, we investigate the mechanisms by which biological tissues recover after injury. We explore this question on adipose tissue, using the mathematical framework recently developed in Peurichard et al., J. Theoret. Biol. 429 (2017), pp. 61-81. Our assumption is that simple mechanical cues between the Extra-Cellular Matrix (ECM) and differentiated cells can explain adipose tissue morphogenesis and that regeneration requires after injury the same mechanisms. We validate this hypothesis by means of a two-dimensional Individual Based Model (IBM) of interacting adipocytes and ECM fiber elements. The model successfully generates regeneration or scar formation as functions of few key parameters, and seems to indicate that the fate of injury outcome could be mainly due to ECM rigidity.

Compressed Fixation Combined with Vacuum-Assisted Closure for Treating Acute Injury of the Heel Fat Pad.

BACKGROUND Treating acute injury of the heel fat pad is different from treating common soft tissue damage. Due to the paucity of literature on the topic, we described our initial experience treating acute injury of the heel fat pad to determine the ideal treatment method. MATERIAL AND METHODS A total of 53 patients with acute injury of the heel fat pad admitted to our hospital were selected for the study and were randomly divided into 2 groups: the compressed fixation combined with vacuum-assisted closure group and the only reimplanted and sewn group. Twenty-seven of the heel fat pads were compressed and fixed using a flat, hard piece of plastic and hollow screws; then, they were covered with a vacuum-assisted closure device. The other 27 were only sewn without tension. The clinical results were evaluated according to the American Orthopedic Foot and Ankle Society hindfoot score and the British Medical Research Council function evaluation criteria RESULTS In the compressed fixation combined with vacuum-assisted closure group, flaps of 12 feet with retrograde avulsion injury survived successfully. Partial flap necrosis occurred in 8 feet. Seven feet underwent repair using the neurocutaneous vascular resupinated island flap. Results were excellent or good for 74% of patients according to the AOFS. However, in the only reimplanted and sewn group, results were excellent or good for 44% of patients according to the AOFS. CONCLUSIONS Compressed fixation with vacuum-assisted closure is effective for treating acute injury of the heel fat pad, with high success rates and good utility.

Fat Fracture: A Rare Cause of Anterior and Medial Knee Pain in a Professional Baseball Player.

Blunt trauma to the anterior knee typically results in a contusion or fracture of the patella. Additionally, injury to the extensor mechanism may come from a partial or full disruption of the patellar or quadriceps tendon. A professional baseball player suffered an injury to his knee after he collided with an outfield wall. Acute swelling in the suprapatellar soft tissues concealed a palpable defect, which initially was suspected to be an injury to the quadriceps tendon. Magnetic resonance imaging of the knee revealed an intact extensor mechanism; moreover, a fracture of the subcutaneous fat anterior to the quadriceps tendon was evident and diagnosed as a fat fracture. Fat fracture is a rare diagnosis, and to the best of our knowledge, this is the first reported diagnosis in a professional athlete. Conservative management including, but not limited to, range of motion exercises, hydrotherapy, and iontophoresis effectively treated the athlete's injury.

Tumors and tumor-like lesions of infrapatellar fat pad and surrounding tissues: A review of the literature.

The infrapatellar fat pad (IFP) is an intracapsular structure with critical importance both mechanically and endocrinologically. Its dysfunction must be considered while clinically investigating the symptoms arising from the knee joint. Infrapatellar fat pad may be subject to trauma, impingement, inflammation or tumoral formations. Although tumors arising within or adjacent to IFP are not extremely rare, the literature can only provide limited information about them. This article aims to briefly review the current literature on tumors and tumor-like lesions of the IFP and surrounding tissues; focusing on diagnosis and treatment management.

The Enigma of "Traumatic Pseudolipoma" and "Traumatic Herniation of Buccal Fat Pad": A Systematic Review and New Classification System of Post-Traumatic Craniofacial Fatty Masses.

PURPOSE: Intraoral traumatic herniation of the buccal fat pad has been reported using various terms such as traumatic pseudolipoma, traumatic prolapse of buccal fat pad, and traumatic avulsion of buccal fat pad. Because there is no uniformity in nomenclature, this condition needs to be distinguished from other entities such as post-traumatic pseudolipoma and lipoma and pseudoherniation of the buccal fat pad. MATERIALS AND METHODS: A systematic review and thorough search of the literature was planned in online databases such as PubMed, Medline, Scopus, Embase, and Google Scholar. The keywords used were traumatic pseudolipoma, traumatic herniation of buccal fat pad, and traumatic prolapse of buccal fat pad. Of 95 articles initially screened, 45 were included in the study. All pertinent data were extracted by the authors independently. Extracted data were cross-examined for any discrepancy. Summary statistics were not used because the research question did not support pooling of data. RESULTS: Only 24 cases were found to have reported the condition correctly. Terms such as traumatic pseudolipoma were used synonymously and erroneously for this condition. CONCLUSION: Based on the gross inaccuracy in reporting, the authors propose a new comprehensive classification of post-traumatic craniofacial fatty masses.

Evaluation of Paraspinal Fat Pad as an Indicator of Posterior Ligamentous Complex Injury in Cervical Spine Trauma.

Purpose To determine if the obliteration of a cervical space, the paraspinal fat pad (PFP), can be used as an indicator at computed tomography (CT) of an injury of cervical spine posterior ligamentous complex (PLC). Materials and Methods This retrospective study was approved by the institutional board review; written informed consent was obtained from healthy subjects and was waived for patients. First, PFP appearance was evaluated in an anatomic specimen and in 10 healthy subjects on spine CT scans by three radiologists (readers 1, 2, and 3) working in consensus. Then, in 85 patients with suspicion of cervical spine trauma following high-velocity trauma, readers 2 and 3 reviewed in consensus the cervical spine CT (reference for fracture and luxation) and 1.5-T magnetic resonance images (T1, T2, and short inversion time inversion-recovery sequences; reference for ligament and disk injuries and contusion or occult fracture) for traumatic injuries. CT appearance of PFP was independently analyzed by readers 1 and 2, and interobserver agreement (weighted kappa) was calculated. Relationships between PFP changes and injuries and descriptive analysis were calculated by using logistic regression and Fisher test, respectively. Results The PFP could be identified as a well-circumscribed fatty area between cervical spine and posterior muscles. Interobserver agreement was 0.76. An abnormal PFP was associated with PLC (P < .001) and arch (P = .006) injuries but not with body (P = .056), longitudinal ligaments (P = .412), or disk (P = .665) injuries. Sensitivity, specificity, positive predictive value, and negative predictive value for PLC injuries were 55% (11 of 20), 97% (38 of 39), 92% (11 of 12), and 81% (38 of 47), respectively. Conclusion PFP changes on CT scans are significantly associated with injuries of PLC in patients with spine cervical trauma. © RSNA, 2016 Online supplemental material is available for this article.

Imaging of traumatic injury and impingement of anterior knee fat.

Fat is not just used by the body as bulk tissue. In addition to its role in storing energy and regulating hormone action, fat is used in some parts of the body for its mechanical properties. The anatomy of anterior knee fat is more complex than it appears at first sight and is capable of withstanding considerable compressive and shear stress. Specific lesions occur when such mechanical stress exceeds the physiological limits and are yet little known. Superficial fat can be the site of either acute injury by closed degloving called the Morel-Lavallée lesion or chronic injury, when subject to repeat excessive shear forces, due to more complex and less well-defined disruptions that result in pseudo-bursitis. There are three main anterior, intracapsular and extrasynovial fat pads in the knee joint, which are the infrapatellar fat pad (IFP) or Hoffa's fat pad, the quadriceps fat pad and the prefemoral fat pad. The IFP plays an important role as a mechanical shock absorber and guides the patella tendon and even the patella itself during flexion-extension movements. In response to repeated excessive stress, an inflammatory reaction and swelling of the IFP is first observed, followed by a fibrotic reaction with metaplastic transformation into fibrous, cartilaginous or bone tissue. More rarely, the two other deep fat pads (quadriceps and prefemoral) can, if subject to repeated stress, undergo similar restructuring inflammatory reactions with metaplasia resulting in tissue hardening, anterior pain and partial loss of function.

Running Injuries: The Infrapatellar Fat Pad and Plica Injuries.

When considering knee pain in runners, clinicians differentiate sources of symptoms and determine their cause. Knee problems arise when a runner increases the amount/frequency of the loading through the lower limb. The way the loading is distributed through the knee determines which tissues are abnormally loaded. Knee problems cannot be considered in isolation, requiring a thorough investigation of static and dynamic lower limb mechanics, and footwear and surfaces. This article examines potential sources of knee pain and explores the role of the infrapatellar fat pad and synovial plica in the mechanics of the knee and its involvement in knee symptoms.

Magnetic resonance imaging of Hoffa's fat pad and relevance for osteoarthritis research: a narrative review.

OBJECTIVE: To give an illustrative overview of Hoffa's fat pad pathology with a radiologic emphasis on the anatomy, on technical considerations, and on imaging differential diagnoses in the context of osteoarthritis (OA) imaging research. DESIGN: A PubMed database search including only English literature and covering a 20 year period was performed. The search was based on but no limited to the query terms "Hoffa", "Hoffa's fat pad" or "infrapatellar fat pad (IPFP)" in combination with "synovitis", "OA", and "magnetic resonance imaging (MRI)". The literature search yielded 289 publications that were screened for relevance; additional references were included when these were considered of importance. RESULTS: Several anatomic variants and pathologic conditions may be encountered when assessing Hoffa's fat pad including tumors and tumor-like lesions such as osteochondroma, tenosynovial giant cell tumor (TGCT) (and pigmented nodular synovitis) and arthrofibrosis, traumatic changes including contusions and anatomic variants such as recesses. The latter may be accountable for differences in cross-sectional area or volume changes over time. Signal changes are commonly used in OA research as surrogate markers for synovitis but are non-specific findings. CONCLUSIONS: Quantitative approaches to evaluate 3D parameters of Hoffa's fat pad are increasingly applied and their role in regard to structural progression and clinical manifestations of disease needs to be further elucidated. In applying such approaches, knowledge of the detailed anatomy and potential pitfalls that may be a result of anatomical variants, inflammatory disease manifestations and additional diverse pathologies encountered seems to be paramount.

Enxerto autólogo de células-tronco derivadas do tecido adiposo: uma nova visão de sua aplicação no tratamento de queimados e na cirurgia plástica reparadora / Adipose tissue-derived stem cell autologous grafts: a new approach to application in the treatment of burn victims and reconstructive plastic surgery

No Brasil, 1 milhão de acidentes com queimaduras acontecem por ano e as infecções são responsáveis por 75% dos óbitos nestes pacientes, além de deixar lesões que ocasionam deformidades nas áreas atingidas. Sendo assim, o objetivo deste trabalho é fornecer uma visão atual sobre células-tronco mesenquimais (MSCs), com ênfase nas células-tronco derivadas do tecido adiposo (ADSCs), associadas a gel de plasma, gel de fibrina e membranas (scaffold). O uso de géis e membranas tendem a auxiliar o crescimento celular visando sua possível aplicação na Cirurgia Plástica Reparadora para o tratamento pacientes queimados ou que necessitam de enxerto de pele. O presente trabalho abordou de forma exploratória e narrativa o tema células-tronco mesenquimais, células-tronco mesenquimais derivadas do tecido adiposo, gel de fibrina, gel de plasma e scaffold. O tipo de pesquisa empregada foi conduzido com coleta de informações utilizando-se a Biblioteca Virtual em Saúde (BVS) e PubMed. O número absoluto de artigos publicados relacionados ao tratamento de queimaduras é considerável. Até o momento, a quantidade de pesquisas relacionadas à terapia com células-tronco derivadas do tecido adiposo, gel de fibrina, gel de plasma e scaffold para o tratamento de queimaduras apresenta-se escassa. O autoenxerto de ADSCs associado a biocurativos torna-se uma perspectiva promissora na Cirurgia Plástica Reparadora para o tratamento e recuperação de pacientes que sofreram queimaduras ou outros acidentes que necessitam de enxerto de pele. Estes recursos podem reduzir a dor e prover a dessecação da lesão, promovendo neovascularização e a reepitelização da ferida.

In Brazil, 1 million burn accidents occur annually, and subsequent wound infections account for 75% cases of deaths among these patients, in addition to inducing deformities in the affected areas. Therefore, the aim of this study was to discuss the current status of mesenchymal stem cells, with an emphasis on adipose-derived stem cells (ADSCs), in combination with plasma gel, glue fibrin, and membranes (scaffold). The use of gels and membranes supports cell growth, and aims at potential application in reconstructive plastic surgery for the treatment of burn patients or individuals requiring skin grafts. This study explores and discusses the role of mesenchymal stem cells, adipose-derived mesenchymal stem cells, glue fibrin, plasma gel, and the scaffold. This research collected information from the Virtual Health Library (VHL) and PubMed. A considerable number of articles have been published on burn treatment. However, there is little research on burn treatment with ADSCs, glue fibrin, plasma gel, and scaffold. An ADSC autograft combined with a biological dressing is promising in reconstructive plastic surgery for the treatment and recovery of burn patients or individuals with other injuries that require skin grafts. These features can reduce pain and aid in drying of the lesion, thus promoting neovascularization and wound reepithelialization.

Role of adiponectin in adipose tissue wound healing.

The purpose of this study was to investigate the mechanism behind adipose tissue wound healing (ATWH). The preadipocyte cell line 3T3-L1 was cultured and expression of adiponectin receptors (AdipoR1/2) was detected by immunohistochemistry and reverse transcription polymerase chain reaction. The concentration of adiponectin secreted at different cell densities was measured by enzyme-linked immunosorbent assay, while preadipocyte proliferation and migration were determined in vitro by MTT and wound closure assays. AdipoR1/2 were found to be expressed in 3T3-L1 preadipocytes. There were no statistically significant differences in the concentrations of adiponectin secreted by cell solutions of different densities (P > 0.05). In addition, adiponectin was seen to promote the growth and migration of preadipocytes. In conclusion, adiponectin may regulate ATWH by promoting preadipocyte proliferation and migration, and its systemic and/or local application is proposed as a promising therapeutic approach for the treatment of wounds incurred as a result of surgery.

Central defect type partial ACL injury model on goat knees: the effect of infrapatellar fat pad excision.

BACKGROUND: The mid-substance central defect injury has been used to investigate the primary healing capacity of the anterior cruciate ligament (ACL) in a goat model. The sagittal plane stability on this model has not been confirmed, and possible effects of fat pad excision on healing have not been evaluated. We hypothesize that excising the fat pad tissue results in poorer ligament healing as assessed histologically and decreased tensile strength of the healing ligament. We further hypothesize that the creation of a central defect does not affect sagittal plane knee stability. METHODS: A mid-substance central defect was created with a 4-mm arthroscopic punch in the ACLs of right knees of all the subjects through a medial mini-arthrotomy. Goats were assigned to groups based on whether the fat pad was preserved (group 1, n = 5) or excised completely (group 2, n = 5). The left knees served as controls in each goat. Histopathology of the defect area along with measurement of type I collagen in one goat from each group were performed at 10th week postoperatively. The remaining knees were evaluated biomechanically at the 12th week, by measuring anterior tibial translation (ATT) of the knee joints at 90° of flexion and testing tensile properties (ultimate tensile load (UTL), ultimate elongation (UE), stiffness (S), failure mode (FM)) of the femur-ACL-tibia complex. RESULTS AND DISCUSSION: Histopathology analysis revealed that the central defect area was fully filled macroscopically and microscopically. However, myxoid degeneration and fibrosis were observed in group 2 and increased collagen type I content was noted in group 2. There were no significant differences within and between groups in terms of ATT values (p = 0.715 and p = 0.149, respectively). There were no significance between or within groups in terms of ultimate tensile load and ultimate elongation; however, group 2 demonstrated greater stiffness than group 1 that was correlated with the fibrotic changes detected microscopically (p = 0.043). CONCLUSIONS: The central defect type injury model was confirmed to be biomechanically stable in a goat model. Resection of the fat pad was noted to negatively affect defect healing and increase ligament stiffness in the central defect injury model.

Hoffa's fracture - lateral meniscus obstructing the fracture reduction - a case report.

Hoffa's fracture is a coronal fracture of the posterior femoral condyle and is an unusual injury. It can be easily missed on plain radiographs. There is no dearth of literature on Hoffa's fracture, its various presentations, management and rehabilitation principles. The intra-articular nature of the fracture, vulnerable blood supply of the posterior femoral condyle, involvement of the weight bearing articular surface of the knee and the unstable fracture pattern necessitate the surgical management. We encountered an unusual case of Hoffa's fracture where the lateral meniscus was blocking the reduction of fractured fragments. The patient required mini arthrotomy to remove the meniscus from in between the bone fragments. The fracture was fixed with two anteroposterior screws and knee was immobilised in extension. A gentle knee range of movements was commenced after the wound had healed but weight bearing was delayed for 12 weeks.

The evaluation of new multi-material human soft tissue simulants for sports impact surrogates.

Previous sports impact reconstructions have highlighted the inadequacies in current measures to evaluate the effectiveness of personal protective equipment (PPE) and emphasised the need for improved impact surrogates that provide a more biofidelic representation of human impact response. The skin, muscle and subcutaneous adipose tissues were considered to constitute the structures primarily governing the mechanical behaviour of the human body segment. A preceding study by Payne et al. (in press) investigated the formulation and characterisation of muscle tissue simulants. The present study investigates the development of bespoke blends of additive cure polydimethysiloxane (PDMS) silicones to represent both skin and adipose tissues using the same processes previously reported. These simulants were characterised mechanically through a range of strain rates and a range of hyperelastic and viscoelastic constitutive models were evaluated to describe their behaviour. To explore the worth of the silicone simulants, finite element (FE) models were developed using anthropometric parameters representative of the human thigh segment, derived from the Visible Human Project. The multi-material silicone construction was validated experimentally and compared with both organic tissue data from literature and commonly used single material simulants: Dow Corning Silastic 3480 series silicones and ballistics gelatin when subject to a representative sports specific knee impact. Superior biofidelic performance is reported for the PDMS silicone formulations and surrogate predictions.