Hoffa's Fat Research Articles

„Fast-Track-Konzepte“ in der Knieendoprothetik: Einsatz von Tranexamsäure und Technik der lokalen intraartikulären Anästhesie

Fast track concepts are used to reduce the risk of perioperative and postoperative complications after total knee arthroplasty. The described concepts are used for patients with indications for the implantation of a total knee prosthesis. Contraindications for fast track concepts are aged patients, dementia, American Society of Anesthesiologists (ASA) grade IV and implantation of large revision or tumor prostheses. Contraindications for tranexamic acid are bleeding in the urinary tract, caution in cases of known epilepsy, individual risk assessment in existing thromboses or increased thrombosis risk, fresh myocardial infarction, conditions following fresh pulmonary embolism, percutaneous transluminal coronary angioplasty (PTCA) and stent implantation. Contraindications for ropivacaine are hypersensitivity (allergy) to ropivacaine and other amide type topical anesthetics and hypovolemia. Preoperative administration of 1 g tranexamic acid and intraoperative local infiltration anesthesia are carried out. After femoral and tibial bone resection and before cementing the femoral and tibial components, approximately 40 ml of ropivacaine (2%) is injected into the posterior capsule. This is followed by injection of the medial and lateral collateral ligaments with approximately 20 ml each and infiltration of Hoffa's fat pad and the extensor apparatus also with approximately 20 ml local anesthetic. After cementing, the subcutaneous tissue is infiltrated with approximately 50 ml ropivacaine solution. On the same day as the operation the patient is mobilized with the help of aphysiotherapist. The patient should, if possible, walk afew steps on crutches. Systemic analgesic treatment is carried out according to the World Health Organization (WHO) staged schemeII with a weak opioid and first stage non-opioid analgesic (nonsteroidal anti-inflammatory drug, NSAID and/or metamizole). Gabapentin can be used as an adjuvant comedication. Medicinal thrombosis prophylaxis is carried out with alow molecular weight heparin for 2weeks postoperatively. In 100 patients who preoperatively received 1 g tranexamic acid and intra-articular infiltration anesthesia, in the evening of the day of the operation the pain was on average 2.1 (±1.8) on the numeric pain rating scale (NPRS). In one patient, there was asensitive deficit of the lower leg and foot. Amotor deficit was not observed. A total of 90 patients were able to raise and straighten leg. On the day of surgery 68 patients were able to walk more than 10steps and 22patients could be mobilized to a standing position. The mean length of hospital stay was 6.6days (5-11days). No infections, thromboses or pulmonary embolisms occurred.

Large Intraarticular Ganglion in Knee Joint: A case report

Ganglion is defined a cystic lesion composed of myxoid matrix having jelly like consistency and is lined by pseudomembrane. Large ganglionic cyst in Hoffa Pad is quite uncommon and only few are mentioned in literatures. A 25-year old female presented with history of gradually worsening anterior knee pain and swelling for 10 months duration, she was disabled due to repeated attacks of knee pain. Magnetic resonance imaging (MRI) shows large intra-articular multilocular cyst. The decision was to do open excision of the cyst in order to decrease the recurrence rate. Histopathological finding shows multi-lobulated cysts with glassy fibrous wall and clear jelly like consistency, which confirm diagnosis. Postoperative period was uneventful and she was doing well during follow up after four months. Large ganglionic cyst developed in Hoffa fat pad of the knee should be considered in deferential diagnosis of intraarticular mass causing pain around the knee. The decision was open excision depending on MRI finding to avoid incomplete resection and prevent recurrence. Keywords:Knee, Ganglion Cyst, Hoffa Fat Pad, MRI Citation:Dagher AE, Hasan FK. Large Intraarticular Ganglion in Knee Joint: A case report. Iraqi JMS. 2019; 17(2): 161-165. doi: 10.22578/IJMS.17.2.10

Strain Ratio Measurements of Patellar and Achilles Tendons With Different Reference Regions in Healthy Volunteers

Strain ratio measurements of tendons vary because of the reference tissue selection. The main purpose of this study is to highlight, in detail, the numeric variability attributable to the use of various reference materials on strain ratio measurements of patellar and Achilles tendons. Measurements were performed at the proximal, middle and distal thirds of the patellar and Achilles tendons on the dominant site of healthy volunteers. A total of 3 references were used: the Hoffa's fat pad for the patellar tendon, the Kager's fat pad for the Achilles tendon, subcutaneous tissue and Aquaflex gel pads (Parker Laboratories, Fairfield, NJ, USA) for both tendons. Although the same methods were used by the same physician for each tendon site on repeated measurements, strain ratio values had numeric variability with various reference materials in each measurement. Therefore, comparison of numeric strain ratio results of various studies with various reference materials could confuse the clinical interpretations of these numeric data, and, using a reference material with standard stiffness like Aquaflex ultrasound gel pads, should be considered by verifying these results with further studies.

New scoring system in assessment of Hoffa's fat pad synovitis: A comparative study with established scoring systems.

AIMTo investigate the reliability of the established and new scoring methods for Hoffa’s fat pad synovitis using magnetic resonance imaging (MRI).METHODSA total of 139 knees of 115 patients who underwent MRI of the knee with and without gadolinium contrast were enrolled in this study. Proton density (PD)-weighted, PD-weighted fat-suppressed (PD-FS), and postcontrast T1-weighted fat-suppressed (T1CE) images were used for evaluation. Using contrast and non-contrast images, our grading method for synovitis was performed to measure synovial thickness and signal intensity changes of the fat pad [Synovial membrane (SM) score], which was compared with the established methods, including MRI Osteoarthritis Knee Score (MOAKS), parapatellar synovitis score, Whole-Organ Magnetic Resonance Imaging Score (WORMS), and suprapatellar effusion diameter. Intraclass correlation coefficients (ICC) for intra and interobserver reproducibility and Spearman correlation coefficients (r) were calculated for the parapatellar synovitis score and each scoring method.RESULTSAll of the scores presented substantial to almost perfect intrareliability. Among three readers, effusion diameter had substantial to almost perfect interreliability (ICC = 0.68-0.81) and WORMS had substantial interreliability (ICC = 0.61-0.70). For two out of three readers, there was substantial interreliability for the thickness score in T1CE (ICC = 0.55-0.69), SM scores in T1CE (ICC = 0.56-0.78) and PD-FS (ICC = 0.51-0.79), and parapatellar synovitis score in T1CE (ICC = 0.53-0.72). The parapatellar synovitis score was significantly correlated with the thickness score in T1CE (r = 0.70) and the SM score in T1CE (r = 0.81) and PD-FS (r = 0.65).CONCLUSIONThe newly proposed quantitative thickness score on T1CE and the semi-quantitative SM score on T1CE and PD-FS can be useful for Hoffa’s fat pad synovitis.

Superolateral Hoffa's Fat Pad Edema and Trochlear Sulcal Angle Are Associated With Isolated Medial Patellofemoral Compartment Osteoarthritis

PurposeTo evaluate whether mediopatellar plica and knee morphometric measurements obtained from magnetic resonance imaging (MRI) studies are associated with isolated medial patellofemoral osteoarthritis in young adults. MethodsMRI studies from 60 patients with isolated medial patellofemoral osteoarthritis and 90 control patients with normal knee MRI studies were reviewed. The presence of mediopatellar plica, the presence of edema in the superolateral aspect of Hoffa's fat pad and suprapatellar fat pad, quadriceps and patellar tendinosis, and axial and sagittal alignment of the patellar and trochlear morphology were assessed using MRI. The relationship between mediopatellar plica, alignment, or morphology and the presence of isolated medial patellofemoral osteoarthritis was evaluated using logistic regression. ResultsSuperolateral Hoffa's fat pad edema (odds ratio [OR] = 3.4, P = .009) and decreased trochlear sulcal angle (OR = 0.95, P = .045) were associated with increased odds of isolated medial patellofemoral osteoarthritis. Decreased lateral patellar tilt (OR = 0.93, P = .087) and patellar tendinosis (OR = 4.13, P = .103) trended toward being associated with increased odds of isolated medial patellofemoral osteoarthritis but were not statistically significant. No significant association was seen between the presence of mediopatellar plica and medial patellofemoral osteoarthritis (OR = 0.95, P = .353). ConclusionsMedial patellofemoral osteoarthritis is associated with trochlear morphology and patellar alignment but not with mediopatellar plica.

Revision surgery in acute periprosthetic knee joint infections

Reduction of pathogens in the knee joint by removal of infected periprosthetic soft tissue, irrigation and modular implant exchange of the total knee arthroplasty (TKA) to eliminate the infection and long-term preservation of the TKA. Early infection of TKA (<4weeks postoperatively); acute hematogenous TKA infection (symptom duration <3weeks). Delayed (>4weeks postoperatively) or chronic TKA infection; TKA loosening; difficult-to-treat pathogens; critical soft tissue with draining sinus tract. Excision of the wound or old surgical scar (=primary approach to the knee joint). Preparation of subcutaneous tissue. Opening the joint capsule. Removal of the old suture in tissue layers. Five tissue samples taken for microbiological and 1tissue sample for histopathological examination using an unused instrument from the knee joint. Debridement of the upper recesses with complete synovectomy. Partial resection of Hoffa's fat body. Eversion of the patella. Resection of peripatellar soft tissue and infection membranes from the medial and lateral part of the capsule. Removal of the polyethylene inlay. Débridement of the posterior joint capsule with protection of vessels and nerve. Systematic removal of avital and infected periprosthetic tissue. Checking for correct fit of the femoral and tibial part of TKA. Antiseptic rinsing of the joint cavity with mechanical cleaning of the TKA. Extensive irrigation of the joint cavity by jet lavage (3-5l saline solution). Glove change of the surgical team and new operation coverage. Inserting new polyethylene. Layerwise wound closure. Removal of redon drain on postoperative day2. Physiotherapy and CPM. Removal of cutaneous suture about 2weeks postoperatively. Antibiotic treatment for 12weeks postoperatively (2weeks intravenous, 10weeks per oral). Checking of inflammatory markers. Using correct indications and therapy, up to 90% of patients with acute periprosthetic TKA infection can be successfully treated with infection elimination and TKA preservation.

Correlation of benign incidental findings seen on whole-body PET-CT with knee MRI: patterns of 18F-FDG avidity, intra-articular pathology, and bone marrow edema lesions.

To correlate patterns of 18F-FDG uptake on whole-body PET-CT with MR findings and compare the degree of FDG activity between symptomatic and asymptomatic knees. Retrospective database query was performed using codes for knee MRI as well as whole-body PET-CT. Patients with malignant disease involving the knee or hardware were excluded. Patients who had both studies performed within 1year between 2012 and 2017 were included for analysis. Knee joint osteoarthrosis, meniscal and ligamentous integrity, presence of joint effusion, and synovitis were assessed and recorded. Bone marrow edema lesions (BMELs) were identified, segmented, and analyzed using volumetric analysis. SUVmax was assessed over the suprapatellar joint space, intercondylar notch and Hoffa's fat pad. Symptomatic and asymptomatic knees were compared in patients with unilateral symptoms. Twenty-two cases (20 patients) with mean age 63.3years (range, 36-91years) were included. Two patients had bilateral pain. The most FDG avid regions in both symptomatic and asymptomatic knees were the intercondylar notch (SUVmax = 1.84 vs. 1.51), followed by suprapatellar pouch (SUVmax = 1.74 vs. 1.29) and Hoffa's fat pad (SUVmax = 1.01 vs. 0.87). SUVmax was significantly associated with cartilage loss (mean modified Outerbridge score) (r = 0.60, p = 0.003) and degree of synovitis (r = 0.48, p = 0023). Overall, mean SUVmax was significantly higher in the presence of a meniscal tear (1.83 ± 0.67 vs. 1.22 ± 0.40, p = 0.030). Nine patients had BMELs (volume: range = 0.6-27.8, mean = 7.79) however there was no significant association between BMEL volume and SUVmax. Higher FDG activity correlates with intra-articular derangement and the intercondylar notch represents the most metabolically active region of the knee.

Celecoxib modulates release of different prostanoid subtypes by intra-articular tissues: towards celecoxib based intra-articular treatment for OA modulation?

Purpose: Celecoxib is currently used as an analgesic in knee osteoarthritis (OA) patients with proven efficacy. Besides solely being a drug with analgesic properties, evidence on the OA disease modifying properties of celecoxib is accumulating. On the other hand, other studies do not confirm OA disease modifying properties of celecoxib. However, these studies evaluated effects of orally administered celecoxib, which not surprisingly will result in lower local concentrations of celecoxib in the knee joint. In this study we hypothesized that celecoxib can be used as an OA-modulatory drug when injected intra-articularly in the knee joint. Since intra-articular administration of celecoxib means that the drug will interact with different intra-articular tissues such as the cartilage, synovium, Hoffa's Fat Pad (HFP) and meniscus we first evaluated the ability of celecoxib to modulate prostanoid release from these intra-articular tissues. Furthermore, we investigated whether prostanoid-reducing actions of celecoxib on different intra-articular tissues is accompanied by a modulation of the expression of aggrecanases, which are important proteolytic enzymes involved in OA pathophysiology. Finally, we sought to determine potential chondroprotective effects of a single intra-articular celecoxib bolus injection in the rat ACLT/pMMx model for OA. Methods: Upon medical ethical approval, cartilage, synovium, HFP and meniscus were obtained after total knee replacement from nine patients with knee OA. Explants were generated and cultured at a ratio of 100 mg tissue per mL culture medium for 24 hours in the presence or absence of 10 μM celecoxib. Presence of prostaglandin subtypes PGE2, PGF2α, PGD2 and (thromboxane B2) TXB2 was determined quantitatively by specific ELISAs. Gene expression levels of ADAMTS4 and ADAMTS5 was evaluated in the intra-articular tissues by means of RT-qPCR. For in vivo experiments OA was induced by performing anterior cruciate ligament transection (ACLT) + partial medial menisectomy (pMMx) in the right knees of 14 male Lewis rats (12-weeks old). Four weeks after OA induction, both the OA-induced and contralateral healthy knees were injected with 25 μL of 0.9 % NaCl or 9.7 nM celecoxib (92.25 ng celecoxib). Twelve weeks after injection, rats were sacrificed and OA severity was assesed by two blinded observers using the OARSI histopathology initiative for the rat (n = 7 per experimental group). Results: Average concentration ranges for the different prostanoids were 26216-385039 pg/mL for PGE2, 5496-69,574 pg/mL for PGF2α, 3848-43830 for PGD2 and 388-9102 pg/mL for TXB2. Celecoxib, at a dose of 10 μM, was able to significantly reduce PGE2, PGF2α, PGD2 and TXB2 release in cartilage, synovium, HFP and meniscus. Average fold reduction in prostanoid release for different intra-articular tissues tested ranged from 25- to 62-fold for PGE2, 9-fold to 20-fold for PGF2α, 8-fold to 23-fold for PGD2 and 2- to 5-fold for TXB2. Celecoxib significantly reduced gene expression levels of both ADAMTS4 and ADAMTS5 in cartilage, synovium, HFP and meniscus. OA levels based upon OARSI scoring were significantly reduced in OA-induced knees treated with bolus celecoxib (P = 0.009 by observer 1 and P = 0.032 by observer 2) compared to OA-induced knees injected with 0.9% NaCl (Fig. 1). Conclusions: Different intra-articular tissues secrete various prostanoid subtypes. These prostanoid subtypes are involved in catabolic processes and celecoxib is able to reduce the release of these prostanoids from cartilage, synovium, HFP and meniscus, but is also able to reduce the expression of aggrecanases which are important enzymes involved in cartilage matrix degradation. A single bolus injection with celecoxib protects against OA progression in vivo and therefore this study reinforces the potential of celecoxib as a potential OA disease-modifying drug when used intra-articularly.

Superolateral Hoffa's fat pad (SHFP) edema and patellar cartilage volume loss: quantitative analysis using longitudinal data from the foundation for the national institute of health (FNIH) osteoarthritis biomarkers consortium

Purpose: To determine the association of superolateral Hoffa's fat pad (SHFP) edema and patellofemoral joint structural damages in participants of Foundation for the National Institute of Health Osteoarthritis Biomarkers Consortium study. Methods: Baseline and 24-month MRI of 600 subjects were assessed. The presence of SHFP edema and patellar morphology metrics were determined using baseline MRI. Quantitative patellar cartilage volume and semi-quantitative MRI Osteoarthritis Knee Score (MOAKS) variables were extracted. The associations between SHFP edema and patellar cartilage damage, bone marrow lesion (BML), osteophyte, and morphology were evaluated in cross-sectional model. In longitudinal analysis, the association between edema and cartilage volume loss (defined using reliable change index) and MOAKS worsening were evaluated. Results: In cross-sectional evaluations, SHFP edema was associated with simultaneous lateral patellar cartilage/BML defects and inferior-medial patellar osteophyte size. A significant positive correlation between the degree of patella alta and SHFP edema was detected. The presence of edema was associated with 24-month cartilage volume loss (odds ratio(OR):2.11, 95%confidence interval:1.46–3.06) and medial patellar BML size (OR:1.92(1.15–3.21)) and number (OR:2.50(1.29–4.88)) worsening. Conclusions: The presence of SHFP edema could be considered as a predictor of future patellar cartilage loss and BML worsening, and an indicator of simultaneous cartilage, BML, and osteophyte defects.

Large-scale secretome analyses of mesenchymal stromal cells from adult joint tissues and umbilical cord: an in vitro comparative study to unveil their immunoregulatory potential

Purpose: Mesenchymal stromal cells are multipotent progenitor cells residing in connective tissues with the capacity to differentiate into cartilage, bone, muscle or adipose tissue. Besides their differentiation potential, MCSs can also regulate immunoresponses in a paracrine manner by both cell-cell contact mechanisms and the release of soluble immunomodulators. In fact, during the last years, the anti-inflammatory and immunoregulatory properties of MSCs have gained more attention than their differentiation properties. Despite the increased awareness about the potential of MSCs to promote a tissue-healing microenvironment, the molecular mechanisms are not completely understood, and the predictable divergent immunoregulatory potential of MSCs from different sources has not been addressed. In this study, we compare the immunoregulatory properties of culture supernatants from MSCs isolated from different tissues and do large-scale profiling of the secretomes to characterize the spectrum of released soluble proteins from each cell type. Methods: A mixed enzymatic-explant method was used to isolate cells from different tissues including cartilage (ACs), Hoffa's fat pad (HFPCSs), synovial membrane (SMCSs) and umbilical cords (UCSCs). Stromal cells were characterized for MSCs surface markers according to international society for cellular therapy guidelines. To study the cell secretomes, supernatants from monolayer cultures of all cell types at third passage were collected and studied by large-scale quantitative analyses using quantitative label-free LC/MS-MS spectrometry. We also investigated groups of selected cytokines, chemokines, growth factors and proteases involved in tissue remodelling and inflammation in the cell supernatants by multiplex antibody-based immunodetection. Furthermore, in vitro functional assays using mitogen-activated lymphocytes were applied to investigate the immunomodulatory potential of cell supernatants. Results: All stromal cells expressed classical MSCs surface markers. Secretome analyses revealed more proteins identified in the supernatants of ACs (709) compared to HFPSCs (641), SMSCs (567) and UCSCs (653). Hierarchical clustering of identified proteins showed two major clusters with UCSCs in one cluster and stromal cells from adult joint tissues in another cluster. Qualitative comparison of identified proteins using gene ontology biological process databases showed similar numbers of proteins involved in the catabolic process (25% in ACs and 27% in all other stromal cells) and immunoregulation (19% in both ACs and UCSCs, 20% in HFPSCs and 21% in SMSCs). However, comparative expression of selected proteins involved in ECM remodelling revealed the presence of MMP1 in UCSCs at a significantly low level compared to stromal cells from adult joint tissues. In addition, other identified MMPs including MMP2, MMP3, MMP7, MMP10 and MMP14 were not detected in the cell supernatants of UCSCs. The presence of TGF-β1 was also higher in the UCSCs compared to other stromal cells. In line with these observations, quantitative determination of selected cytokines and MMPs using Luminex and Elisa also revealed the significantly lower concentration of IL-17 and MMPs including MMP1, MMP3, MMP7 and MMP9 in the culture supernatants of UCSCs. Importantly, the concentration of TGF-β1 and PGE-2 was significantly higher in the UCSCs. Mitogen-activated lymphocyte functional assay also confirmed significant blocking of lymphocyte proliferation and migration in the presence of conditioned medium (CM) from UCSCs compared to CM from ACs, HFPSCs and SMSCs. Furthermore, lymphocytes secretion of TNF-α and IFN-γ was significantly decreased in the presence of UCSCs-CM. Conclusions: Our results show that the secretome of culture expanded UCSCs is considerably different than the secretome of stromal cells harvested from adult tissues, demonstrating enhanced expression of immunosuppressive molecules and reduced expression of proteases and catabolic factors. In functional lymphocyte activation assays, only conditioned medium from UCSCs exerted suppressive effects. Collectively, our data suggest that UCSCs have superior immunoregulatory properties and would represent the best cell source to promote a tissue-healing microenvironment.

The Unexplored Role of Intra-articular Adipose Tissue in the Homeostasis and Pathology of Articular Joints.

Intra-articular adipose tissue deposits known as articular fat pads (AFPs) are described to exist within synovial joints. Their assumed role in normal joint biomechanics is increasingly objectivized by means of advanced methods of functional imaging. AFPs possess structural similarity with body subcutaneous white adipose tissue (WAT), however, seems to be regulated by independent metabolic loops. AFP dimension are conserved during extreme WAT states: obesity, metabolic syndrome, lipodystrophy, and cachexia. Hoffa fat pad (HFP) in the knee is increasingly recognized as a major player in pathological joint states such as anterior knee pain and osteoarthritis. HFP contains numerous population of mesenchymal and endothelial progenitors; however, the possible role of mature adipocytes in the maintenance of stem cell niche is unknown. We propose that AFP is an active component of the joint organ with multifunctional roles in the maintenance of joint homeostasis. Endowed with a rich network of sensitive nervous fibbers, AFPs may act as a proprioceptive organ. Adipokines and growth factors released by AFP-resident mature adipocytes could participate in the maintenance of progenitor stem cell niche as well as in local immune regulation. AFP metabolism may be locally controlled, correlated with but independent of WAT homeostasis. The identification of AFP role in normal joint turnover and its possible implication in pathological states could deliver diagnostic and therapeutic targets. Drug and/or cell therapies that restore AFP structure and function could become the next step in the design of disease modifying therapies for disabling joint conditions such as osteoarthritis and inflammatory arthritis.

Imaging of Juvenile Hip Conditions Predisposing to Premature Osteoarthritis-Erratum.

HomeRadioGraphicsVol. 38, No. 2 PreviousNext ErrataFree AccessImaging of Juvenile Hip Conditions Predisposing to Premature Osteoarthritis—ErratumCarl Kraus, Rama S. Ayyala, Jonathan K. Kazam, Tony T. WongCarl Kraus, Rama S. Ayyala, Jonathan K. Kazam, Tony T. WongCarl KrausRama S. AyyalaJonathan K. KazamTony T. WongPublished Online:Mar 12 2018https://doi.org/10.1148/rg.2018174019MoreSectionsPDF ToolsImage ViewerAdd to favoritesCiteTrack CitationsPermissionsReprints ShareShare onFacebookTwitterLinked In Originally published in:RadioGraphics 2017;37(7):2204–2205 • https://doi.org/10.1148/rg.2017170067Imaging of Juvenile Hip Conditions Predisposing to Premature OsteoarthritisCarl Krsaus, Rama S. Ayyala, Jonathan K. Kazam, Tony T. WongErratum in:RadioGraphics 2018;38(2):662 • https://doi.org/10.1148/rg.2018174019Supplemental presentation, slide 8: The line beginning with “Acetabular line” should read as follows: “Acetabular line: Drawn connecting the superolateral acetabular roof to the ipsilateral triradiate cartilage (angle formed with horizontal line should be less than [not greater than] 30°).”Article HistoryPublished online: Mar 12 2018Published in print: Mar 2018 FiguresReferencesRelatedDetailsCited ByMedium-term outcomes of total hip arthroplasty in juvenile patientsFrancescoLuceri, IlariaMorelli, Carlo MariaSinicato, AlbertoDella Grazia, FabioVerdoni, NicolaMaffulli, Giuseppe M.Peretti, DomenicoCurci2020 | Journal of Orthopaedic Surgery and Research, Vol. 15, No. 1Accompanying This ArticleImaging of Juvenile Hip Conditions Predisposing to Premature Osteoarthritis: Pediatric ImagingNov 13 2017RadioGraphicsRecommended Articles Hip Imaging in Athletes: Sports Imaging SeriesRadiology2016Volume: 280Issue: 2pp. 351-369Developmental Hip Dysplasia Diagnosis at Three-dimensional US: A Multicenter StudyRadiology2018Volume: 287Issue: 3pp. 1003-1015Radiography, CT, and MRI of Hip and Lower Limb Disorders in Children and AdolescentsRadioGraphics2019Volume: 39Issue: 3pp. 779-794Relationship of Trochlear Morphology and Patellofemoral Joint Alignment to Superolateral Hoffa Fat Pad Edema on MR Images in Individuals with or at Risk for Osteoarthritis of the Knee: The MOST StudyRadiology2017Volume: 284Issue: 3pp. 806-814Imaging of Sports-related Injuries of the Lower Extremity in Pediatric PatientsRadioGraphics2016Volume: 36Issue: 6pp. 1807-1827See More RSNA Education Exhibits Developmental Dysplasia of the Hip: Clinical and Imaging Findings for Early Diagnosis and TreatmentDigital Posters2018To Correctly Understand the Graf Classification—Recognize the Relationship of the Black Ball to the White WallDigital Posters2020Adult Hip Dysplasia - An Updated Imaging ApproachDigital Posters2020 RSNA Case Collection Developmental hip dysplasia RSNA Case Collection2021Osteoarthritis of L hipRSNA Case Collection2020Patella FractureRSNA Case Collection2020 Vol. 38, No. 2 Metrics Altmetric Score PDF download

Celecoxib-mediated reduction of prostanoid release in Hoffa's fat pad from donors with cartilage pathology results in an attenuated inflammatory phenotype

The Hoffa's fat pad (HFP) is an intra-articular adipose tissue which is situated under and behind the patella. It contains immune cells next to adipocytes and secretes inflammatory factors during osteoarthritis (OA). In this study, we compared the release profile of prostanoids, which are involved in inflammation, of HFP from OA patients vs patients with a focal cartilage defect (CD) without evidence for OA on MRI and investigated the prostanoid modulatory anti-inflammatory action of celecoxib on HFP. Prostanoid release was analyzed in conditioned medium of HFP explant cultures from 17 osteoarthritic patients and 12 CD patients, in the presence or absence of celecoxib. Furthermore, gene expression of COX enzymes and expression of genes indicative of a pro-inflammatory or anti-inflammatory phenotype of HFP was analyzed. Prostanoid release by HFP from knee OA patients clustered in two subgroups with high and low prostanoid producers. HFP from high prostanoid producers released higher amounts of PGE2, PGF2α and PGD2 compared to HFP from CD patients. PGE2 release by OA HFP was positively associated with expression of genes known to be expressed by M1 macrophages, indicating a role for macrophages. Celecoxib modulated prostanoid release by HFP, and also modulated the inflammation ratio towards a more favorable anti-inflammatory M2 phenotype, most effectively in patients with higher prostanoid release profiles. In knee OA patients with inflamed HFP's, celecoxib may exert positive effects in the knee joint via decreasing the release of prostanoids produced by the HFP and by favorably modulating the anti-inflammatory marker expression in HFP.

A Rare Case of Glomus Tumour on the Knee: Case Report and Literature Review

We present a case of glomus tumour of the knee in an 82-year-old Japanese woman. The patient noticed a painful eruption on her right knee 6 years before our first examination. At first examination, a well-defined, subcutaneous, elastic, firm nodule 1 cm in diameter was present over the central portion of the patella. The lesion was easily surgically removed in block. On gross examination, the excised lesion was a well-defined smooth-surfaced mass measuring 8 mm × 6 mm × 5 mm. Histological and immunohistochemically findings for the nodule were consistent with the diagnosis of glomus Tumour. Pain was resolved immediately postoperatively. As of the last follow-up, 5 months postoperatively, the patient reported continued relief from pain. We summarized reported 29 cases of glomus Tumour of the knee, including the present case. Our summary revealed that glomus Tumours can develop in the knee in various anatomical sites, including the skin, deep adipose tissue, muscle, quadriceps tendon, and Hoffa's fat pad.

Soft Tissue Masses of the Knee Related to a Focal Defect of the Lateral Patellar Retinaculum

We report on the imaging features of 6 soft tissue masses in the anterolateral aspect of the knee related to a focal defect of the lateral patellar retinaculum. In 4 patients (3 female and 1 male; 6-65 years) presenting with nontender palpable soft tissue masses in the anterolateral aspect of their knees, ultrasonography showed a focal defect of the lateral patellar retinaculum with herniation of the Hoffa fat pad, which was only visible in flexion. A magnetic resonance imaging examination performed in 1 case confirmed the defect in the lateral patellar retinaculum but did not show a mass, as the knee was examined only at 10° of flexion. The 2 remaining patients (one male and 1 female; 62 and 55 years) presented with soft tissue masses in their anterolateral knees in both flexion and extension. These masses were related respectively to a lipoma of the Hoffa fat pad and to a ganglion cyst, both herniated through a defect of the lateral patellar retinaculum. Our cases suggest that a focal defect of the lateral patellar retinaculum may be a route for Hoffa fat pad herniation as well as a route for superficial extension of infrapatellar fat lesions such as lipomas and ganglion cysts.

Open versus arthroscopic resection of Hoffa's fat pad tumors like

Background While few comparative studies exist, it has been suggested that open resection of Hoffa's fat pad tumor like provide inferior results when compared with the all-arthroscopic technique. Purpose The purpose of this study was to compare the intermediate-term results of patients undergoing arthroscopic versus open resection for the treatment of tumor like of Hoffa's fat pad. Methods We prospectively reviewed records from 2010–2013 and identified 27 patients (18 arthroscopic, 9 open) with symptomatic Hoffa's fat pad impingement. The mean follow-up for group I (open) and group II (arthroscopic) was 2.3 years and 1.2 years, respectively. The diagnosis was made by clinical exam, MRI imaging and verified by anatomopathology. Lysholm score was obtained pre- and postoperative and at final follow-up. Each patient completed a questionnaire assessing their scar satisfaction, percentage of normal knee function and willingness to have the surgery again. Risk factors for poor outcomes were analyzed. Results There was a significant improvement in their symptoms and function after the surgery at an average follow-up of 14 months. Arthroscopic patients had significantly less pain (P = 0.035) by VAS (0.61 ± 1.02) compared with open (1.59 ± 2.15) at final follow-up. Percentage of normal knee function (89.7% ± 12.5 vs. 92.9% ± 8.6), average operative time (53.1 minutes vs. 41 minutes). The one poor result was because of paresthesia over the distribution of the infrapatellar branch of the saphenous nerve after open resection. Conclusion Open and arthroscopic resection of infrapatellar fat pad are both effective surgeries. Tumors like of the fat pad should be treated by arthroscopic resection because of less residual pain and less complication was found using the arthroscopic technique. In case of high volume of tumors only open excision can provide complete excision.

MRI Findings Consistent with Peripatellar Fat Pad Impingement: How Much Related to Patellofemoral Maltracking?

Peripatellar fat pads are intracapsular extrasynovial adipose cushions that accommodate the changing shape and volume of articular spaces during movement. Variations in bone geometry, passive and active stabilization mechanisms and/or functional demands may lead to peripatellar fat pad abnormalities. While peripatellar fat pads may be affected a variety of conditions such as synovial inflammation, tumor and fibrosis, a mechanical origin should also be considered. Commonly, the clinical term “impingement” is used synonymously in the radiological literature to refer to three distinct entities of structural peripatellar fat pad abnormalities: superolateral the infrapatellar fat pad (Hoffa fat pad) edema, suprapatellar fat pad edema, and prepatellar fat pad edema, implying a mechanical origin of these conditions. The aim of this pictorial review is to describe the normal anatomy of the extensor mechanism of the knee, and discuss the relation of patellofemoral maltracking to the above-mentioned peripatellar fat pad conditions based on current evidence.

Is superolateral Hoffa's fat pad hyperintensity a marker of local patellofemoral joint disease? - The MOST study.

To determine the relation of superolateral Hoffa's fat pad (SHFP) hyperintensity to cartilage damage and bone marrow lesions (BMLs) in the patellofemoral joint (PFJ) and tibiofemoral joint (TFJ). We used data from the 60 and 84-month study visits from the Multicenter Osteoarthritis (MOST) study. SHFP hyperintensity and Hoffa-synovitis were graded from 0 to 3. Cartilage damage and BMLs were scored in the PFJ and TFJ. Structural damage was defined as: any cartilage damage, full-thickness cartilage damage and any BML. Worsening structural damage was defined as any increase in cartilage and BML scores. Logistic regression was used to determine the relation of SHFP hyperintensity and Hoffa-synovitis (>0) to structural damage, adjusting for age, sex and body mass index (BMI). 1,094 knees were included in the study. Compared to knees without SHFP hyperintensity, those with SHFP hyperintensity had 1.2 (95% Confidence Interval (CI), 1.1-1.4), 1.7 (1.3-2.3) and 1.6 (1.3-1.9) times the prevalence of any cartilage damage, full-thickness cartilage damage, and BMLs in the lateral PFJ respectively, and 1.1 (1.0-1.2), 1.3 (1.0-1.8), and 1.2 (1.0-1.4) times the prevalence of any cartilage damage, full-thickness cartilage damage, and BMLs in the medial PFJ. SHFP hyperintensity was associated with worsening BMLs in the medial PFJ (RR: 1.4 (1.0-1.9)). In general, there was no relation between SHFP hyperintensity and TFJ outcomes. Hoffa-synovitis was associated both cross-sectionally and longitudinally with structural damage, regardless of definition, in all compartments. SHFP hyperintensity may be a local marker of PFJ structural damage.

Relationship of Trochlear Morphology and Patellofemoral Joint Alignment to Superolateral Hoffa Fat Pad Edema on MR Images in Individuals with or at Risk for Osteoarthritis of the Knee: The MOST Study.

Purpose To determine the relationship of patellofemoral joint alignment and trochlear morphology to superolateral Hoffa fat pad (SHFP) edema on magnetic resonance (MR) images in older adults with or at risk for osteoarthritis of the knee. Materials and Methods Institutional review board approval and written informed consent were obtained from all subjects. The Multicenter Osteoarthritis Study is a prospective cohort study of older adults with or at risk for osteoarthritis of the knee. Subjects were recruited from Birmingham, Alabama, and Iowa City, Iowa. In this cross-sectional study, patellofemoral joint alignment (bisect offset, patellar tilt angle, and Insall-Salvati ratio), trochlear morphology (sulcus angle, lateral and medial trochlear inclination, and trochlear angle) and SHFP edema were assessed on MR images of the knee. Measures of alignment and morphology were divided into quartiles, and SHFP was determined to be present or absent. Separate logistic regression models were used to determine the relationship of each measure of alignment and morphology to the presence of SHFP edema, with adjustments for age, sex, and body mass index. Results SHFP edema was present in 152 (13.4%) of the 1134 knees that were included. When compared with knees with measurements in the lowest quartile, knees with measurements in the highest quartile for trochlear angle, bisect offset, and Insall-Salvati ratios were 1.6 (95% confidence interval [CI]: 1.0, 2.6), 2.3 (95% CI: 1.3, 4.0), and 8.9 (95% CI: 4.7, 16.9) times more likely to show SHFP edema, respectively. No relationship was found between other measures and SHFP edema. Conclusion A more anterior trochlear facet, a more laterally displaced patella, and knees with patella alta were significantly associated with SHFP edema on MR images in subjects with or at risk for osteoarthritis of the knee. © RSNA, 2017.

Association between lateral patellar osteoarthrosis and knee morphology and alignment in young adults

To assess whether patellar and trochlea morphology and patellar alignment are associated with lateral patellar osteoarthrosis/chondrosis (OAC) in young adults. Magnetic resonance imaging (MRI) images of 183 subjects (81 cases, 102 controls) aged 21-35 years of age were evaluated. Quantitative measurements of patella and trochlea morphology and patellar alignment were obtained. Axial and sagittal MRI images were reviewed to grade the severity of focal cartilage defects along the lateral facet of the patella. Controls had knees without any abnormalities and were compared to cases with mild and severe lateral patellar OAC. Multivariable logistic regression was used to assess associations between measurements and lateral patellar OAC adjusting for body mass index. Cases were more likely to have higher Insall-Salvati ratios (OR=350; p<0.001), shorter ratios of the medial to lateral facets of the patella (OR=1.63×10-3; p<0.001), a shallower (angle closer to 180°) median eminence of the patella (OR=1.063; p=0.009), decreased trochlear cartilage overlap with the patellar cartilage (OR=0.086; p=0.023), and a less angulated lateral patellofemoral angle (OR=0.903; p=0.028), compared to controls. Cases were also more likely to have patellar tendinosis (OR=5.265; p=0.045) and oedema in the superolateral aspect of Hoffa's fat pad (OR=9.872; p<0.001). Patellar and trochlear morphology and patellar alignment are associated with lateral patellofemoral compartment OAC in young adults.