Fat Pad Impingement Research Articles

MRI features of some uncommon causes of painful knee

Aim of the workThe purpose of this study is to describe the MRI features of some uncommon causes of knee pain. Materials and methodsThis is a retrospective study. We reviewed our database including the last 1000 knee MRI examinations done within the period from January 2012 till June 2013. This revision revealed 12 cases with reported variable uncommon diagnoses explaining knee pain. Unenhanced MRI of the knee was performed and included sagittal T1, T2, T2∗ and proton density fat suppression (PDFS), axial T2 and coronal PDFS. Some cases had complementary CT assessment. ResultsThe selected 12 cases included the following; three cases of supero-lateral Hoffa’s pad of fat edema expressing edema signal at the superolateral aspect of the Hoffa’s pad of fat. Three cases with fabella syndrome with chondral and subchondral edema signal at the posterior aspect of the lateral femoral condyle. Two cases with symptomatic bipartite patella showing marrow edema around the patellar synostosis. One case with proximal tibio-fibular synostosis evident on MRI as bony fusion. Two cases with quadriceps (suprapatellar) fat-pad impingement syndrome manifested as edema signal within the supra-patellar fat-pad and lastly one case with lipoma arborescence seen as frond like projections with fat signal protruding into the supra-patellar bursa. ConclusionMRI is a useful tool in evaluation of some uncommon causes of painful knee.

English

INTRODUCTION: Albert Hoffa in 1904 described the condition. Hoffas fat pad disease is commonly encountered in athletes after the second decade. Most common pathology is impingement of fat pad between patella and femoral condyles. CASE PRESENTATION: We report a case of hoffa's fat pad disease of the right knee in a ten year boy. He presented with pain and swelling in the right knee since seven months, diagnosis confirmed with MRI. Symptoms not reduced with conservative treatment and surgical excision performed. Histopathology confirmed hoffa's fat pad disease. Patient was relieved of symptoms 2 weeks post surgery and able to perform activities of daily living. CONCLUSION: Hoffa's fat pad disease is rare in children and MRI is diagnostic. It is INTRODUCTION: Albert Hoffa, German surgeon in 1904 described the condition. Hoffa's disease is associated with chronic anterior knee pain, beneath the patella 1 . Most of the patients present in the fifth decade 2 . Hoffa's fat pad disease is also encountered in athletes after second decade. The youngest patient reported in the literature is eighteen years. We present a ten year old boy suffering from the disease, probably due to cross leg sitting, sports and running. Most common pathology is impingement of fat pad between patellofemoral and tibiofemoral joints.

Is There an Association Between Superolateral Hoffa Fat Pad Edema on MRI and Clinical Evidence of Fat Pad Impingement?

Patients with symptomatic Hoffa fat pad impingement often exhibit fat pad edema on MRI. We studied two patient groups to determine the association between MRI fat pad edema and clinical symptoms of Hoffa fat pad impingement. We studied 34 consecutive patients with an MRI diagnosis of fat pad edema and no injury in the prior year (group 1) and 47 consecutive patients with a knee MRI examination and no injury in the prior year (group 2). Two sports medicine physicians reviewed the clinical records to confirm or exclude symptomatic fat pad impingement. Two musculoskeletal radiologists independently scored 12 Hoffa fat pad locations for the presence of edema, noting the epicenter. Seventeen of the 34 patients in group 1 had clinical symptoms of fat pad impingement, with all 34 having fat pad edema. There was no association between clinical fat pad impingement and fat pad edema in any specific location (p > 0.183), but patients with fat pad impingement had a greater number of regions of edema (p = 0.005, 0.026 for two observers). In group 2, all four patients with clinical fat pad impingement had MRI fat pad edema, but 38 of the 43 patients without clinical impingement had MRI fat edema; 11 of the 38 had edema centered in the superolateral fat pad. Edema is present on MRI in the superolateral region of Hoffa fat pad in patients with clinical fat pad impingement. However, such edema can also be present in patients without symptoms of fat pad impingement.

The association of infrapatellar fat pad oedema with patellar maltracking: a case–control study

To look for any association between oedema in the superolateral portion of the infrapatellar fat pad and patellar maltracking. We compared two groups of knee MRI with regard to five patellar maltracking parameters. The first group included 100 knees with evidence of oedema in the superolateral aspect of the infrapatellar fat pad (the study group). The second group included another 100 knee MRI that had a normal infrapatellar fat pad (the control group). The five patellar maltracking parameters assessed were the trochlear depth, tibial tuberosity-trochlear groove distance (TTTG), patellar translation, patellofemoral angle (PFA) and the Insall-Salvati index. There was a statistically significant difference in the Insall-Salvati index, patellar translation and PFA between the two groups (p value of <0.001, <0.001 and 0.004 respectively, Student's t test). There was a higher prevalence of patella alta, lateral patellar displacement (LPD) and lateral patellar tilt in the study group (p value of <0.001, <0.001 and 0.011 respectively, Fisher's exact test). Sixty out of 100 knees in the study group had at least one abnormal patellar maltracking parameter in comparison to 16 out of 100 knees in the control group (p < 0.001, Fisher's exact test). Oedema in the superolateral portion of Hoffa's fat pad, the MRI feature of fat pad impingement, is associated with patellar maltracking.

Posttraumatic dislodgement of the infrapatellar fat pad: An unusual type of superolateral impingement

The authors report a rare case of dislodgement of the infrapatellar fat pad induced by traumatic hyperflexion. Because of the unusual clinical presentation, open excision was performed to exclude a possible tumoral etiology. This entity seems to be an acute form of superolateral fat pad impingement.

Hoffa’s fat pad impingement treated arthroscopically: related findings on preoperative MRI in a case series of 62 patients

The morphology of painful impingement of the infrapatellar fat pad (Hoffa's disease), which is characterized by inflammation, swelling, hypertrophy, fibrosis, and/or calcifications, has been well described. The purpose of this study was to investigate whether corresponding characteristic MRI findings could be assessed in patients with infrapatellar fat pad impingement. This study includes 62 patients with secondary symptomatic Hoffa's fat pad impingement. In these patients, the fat pad was partially resected until no impingement could be determined at full knee movement. Within a maximum of 3 months before arthroscopic surgery, patients had standardized MR imaging using a 1.5 Tesla unit with the following sequences: sagittal T1-TSE, coronal STIR-TSE, transversal fat-suppressed PD-TSE, and sagittal fat-suppressed PD-TSE (Siemens Magnetom Avanto syngo MR B 15). In this case series, the preoperative MRI appearance of the fat pad was evaluated and compared with a cohort of 255 patients without fat pad impingement but with various knee disorders at arthroscopy as well as the same standardized MRI protocol. In patients with Hoffa's fat pad impingement, morphologic changes such as localized edema of the superior and/or posterior part of the fat pad, a deep fluid-filled infrapatellar bursa, non-visualization of vertical and/or horizontal clefts, fibrosis, and calcifications were noted on MR imaging with remarkable frequency. Besides a significant enlargement of the fat pad, each of these MRI findings was significantly associated with impingement of Hoffa's fat pad (P < 0.05). Besides a moderate kappa score for the detection of intrahoffatic calcifications and vertical clefts, kappa values for each finding showed good inter-observer agreement. Results of logistic regression revealed that edema of Hoffa's fat pad was one of the most important diagnostic MRI criteria for the diagnosis of Hoffa's fat pad impingement. MR imaging allows identification of several changes that may be related to a symptomatic impingement of Hoffa's fat pad. In patients who are suspected of having infrapatellar fat pad impingement, such MRI findings should be considered and distinguished from other causes of anterior knee pain.

Traumatic Patellar Injury - Soccer

HISTORY: A 16 year-old soccer player presented with right knee pain after a direct kick to the patella by an opponent during a game. Since the injury, which occurred three weeks prior to presentation, he was unable to completely extend his right knee. Pain on presentation was aching and rated a 7/10 in intensity. The pain was worse with kneeling, stair ambulation, walking, and running. He also noted some right knee buckling. He continued playing soccer with this pain for the last three weeks and wanted to continue to play. PHYSICAL EXAMINATON: Right knee examination was notable for tenderness over the inferolateral aspect of the patella and the superior aspect of the patellar tendon. The patient was unable to fully actively extend his knee. He did have full passive knee extension and was able to hold the knee in this position. There was significant pain over the inferior pole of the patella with eccentric lowering of the extended knee. Typical pain was provoked with lateral patellar glide. Further testing of the right knee was unremarkable. DIFFERENTIAL DIAGNOSIS: Patellar fracture/contusion Fat pad impingement syndrome Patellar tendinopathy or tendon tear Quadriceps tendon tear TEST AND RESULTS: Right Knee X-Ray: -Vertical fracture of the lateral 1/4th of the patella that is not displaced. It appears to be an old abnormality. MRI Right Knee without Contrast: -Prominence of the lateral aspect of the patella consistent with a synchrondrosis suggesting either a bipartite patella with superimposed injury/bone contusion or reactive edema from patellofemoral tracking abnormality. -Patella alta and partial lateral subluxation of the patella. FINAL/WORKING DIAGNOSIS: Type II Bipartite Patella with superimposed contusion, likely from lateral subluxation of the patella TREATMENT AND OUTCOMES: 1. No return to play initially. 2. Knee immobilizer for 18 days (until he achieved full painless active knee extension). 3. Initiation of physical therapy at 5 weeks post-injury that focused on closed kinetic chain strengthening in functional planes. 4. Gradual increase in running and cutting with trainer and physical therapist at 5 weeks post-injury. 5. Returned to play in 7 weeks post-injury with minimal discomfort. Patient continued strengthening of lower extremities to address patellofemoral tracking.

Impingement of Infrapatellar Fat Pad (Hoffa’s Disease): Results of High-Portal Arthroscopic Resection

We performed a retrospective cohort study with prospective data collection to assess clinical and functional outcomes of painful impingement of the infrapatellar fat pad (Hoffa's disease) treated with high-portal arthroscopic resection. Hoffa's disease as an isolated lesion was confirmed by arthroscopy in 34 patients with recalcitrant anterior knee pain. The visualization portals were made high in the soft spot above the level of the lower pole of the patella. Patients were treated by resection of the affected part of the fat pad and assessed via the Lysholm knee and Tegner activity level scales preoperatively and at 3 months and at 1 year postoperatively, as well as at the conclusion of this study. The mean age of the patients was 38 years (range, 19 to 62 years). The mean duration of symptoms before surgery was 10 months (range, 1 to 22 months). Twelve patients had one or more previous failed arthroscopies at other centers. The mean follow-up period was 68 months (range, 49 to 95 months). The mean improvement in Lysholm score was 44.76, 55.58, and 53.97 at 3 months, at 1 year, and at the latest follow-up, respectively. On the basis of the Tegner activity level, all but 4 patients returned to their preinjury status. A statistically significant negative correlation was found between duration of symptoms and gain in Lysholm score after surgery (Pearson r = -0.58). Three types of lesion were identified. After resection, patients with acute lesions (type 1) had a quicker return to their previous level of activity according to the Tegner scale as compared with patients with chronic lesions (types 2 and 3) (P = .05 and .03, respectively). Patients with Hoffa's disease without any other concomitant pathology can expect resolution or long-term improvement in their symptoms and function after arthroscopic resection. Level IV, therapeutic case series.

A giant extrasynovial osteochondroma in the infrapatellar fat pad: end stage Hoffa’s disease

The infrapatellar fat pad of Hoffa is commonly injured but rarely discussed in the orthopaedic literature. Hoffa's disease is the extension of various traumatic events due to impingement and inflammation of the infrapatellar fat pad and known as a vague reason for anterior knee pain. Inflammation is foreground during acute phase of the disease while impingement due to fibrosis and scar tissue of infrapatellar fat pad plays a major role in the chronic phase. The osteochondroma of the infrapatellar fat pad secondary to the Hoffa's disease can be more problematic. Although, the fibrocartilaginous transformation and osteochondral metaplasia of infrapatellar fat pad was pointed out frequently in the literature, the published papers seem far from clarifying the relation between chronic impingement and formation of osteochondroma. We present a case of a giant ossifying chondroma in the infrapatellar fat pad that resulted from chronic Hoffa's disease. Complete open resection was performed successfully after arthroscopic examination. The infrapatellar fat pad contains the entire progenitor cells for the development of an osteochondroma and chronic impingement may have promoter affect on this issue, thus, an osteochondroma may occur at the end-stage Hoffa's disease.

Prefemoral fat pad: impingement and a mass-like protrusion on the lateral femoral condyle causing mechanical symptoms

We describe a case of prefemoral fat pad impingement between the anterior aspect of the distal femur and the patella undersurface, and a mass-like fatty tissue protrusion on the lateral femoral condyle that caused mechanical symptoms.

Fat-pad impingement after total knee arthroplasty with the LCS A/P-Glide system.

Early follow-up (15.8 months;1-48) of 230 knee replacements with an LCS A/P Glide component indicated an increased occurrence of anterior knee pain due to a fat-pad impingement, necessitating early revision surgery. Unsatisfactory results were observed in 28 knees (12.2%). Thirteen knees (5.7%) were revised on finding the fat-pad impingement, and four knees (1.7%) were scheduled for later revision surgery; the remaining 11 subjects (4.8%) had revision surgery for a different reason. Twenty-six subjects (11.3%) complained about milder but typical symptoms of a fat-pad impingement, and 22 subjects (9.6%) had unspecific mild symptoms. 151 knees (65.7%) were free of pain and demonstrated an excellent result. The total revision rate of 10.4% (24 knees) is higher than described for other implant systems. However, the revision needed to treat the fat-pad impingement (5.7%) consisted of minor surgery only, such as exchange of the mobile bearing or reduction of the fat pad by arthroscopy. The femoral and tibial components were able to be left untouched. Resection of the Hoffa's fat pad is recommended when such an implant system is used, and possible impingement should be investigated intraoperatively before closure.

Arthroscopic resection of an extrasynovial ossifying chondroma of the infrapatellar fat pad: End-stage Hoffa's disease?

Hoffa's disease, an obscure cause of anterior knee pain resulting from impingement and inflammation of the infrapatellar fat pad, was first reported by Albert Hoffa in 1904. Since the initial description, the clinical and pathological processes with an acute-to-chronic progression have been defined. Despite reports of eventual fibrocartilaginous transformation and ossification of the fat pad, no relation has been described between chronic impingement and the development of ossifying chondroma. We present a case of a unilateral, ossifying chondroma in the infrapatellar fat pad that resulted from chronic impingement and repetitive microtrauma. This case shows the radiologic, histologic, and pathologic features of Hoffa's disease. Successful arthroscopic resection is presented. A possible relationship between impingement of the infrapatellar fat pad and the development of ossifying chondroma may exist.

外傷により膝痛を生じた膝蓋下脂肪体舌部かん入症の３症例

We experienced 3 cases of impingement of the infrapatellar fat pad in the patellofemoral joint after direct injury to the knee. The impingement was confirmed by arthroscopy.At extended position, the fat pad was impinged in the patellofemoral joint, however, at flexed position the impingement disappeared.At arthroscopy we used lateral suprapatellar pouch approach and saline was deflated from the knee joint for observation under biological condition. All cases received conservative therapy. Case 1 received casting with the knee in 30° flexion for 1 week. Case 2 received physical therapy as an in-patient. Case 3 received steroid injection to the infrapatellar fat pad and casting with the knee in 30° flexion for 1 week. In every case, symptom disappeared.