The management of solitary tumours of Hoffa's fat pad

Ancient Schwannoma Along the Patellar Tendon: Unveiling a Rare Clinical Phenomenon With Literature Review

Ancient schwannoma, a rare subtype of schwannoma, a benign tumor originating from nerve sheaths, can arise from various nerves, except for the optic, olfactory, spinal, and autonomic nervous systems. Schwannomas are typically characterized by the presence of neoplastic Schwann cells and tend to develop eccentrically. Malignant transformations of schwannomas are exceptionally uncommon. In this case report, a 42-year-old male presented with a painful lump on the front of his left knee. The lump was described as an extra-articular swelling below the kneecap, situated over the patellar tendon. Initially, ultrasonography (USG) indicated the presence of a slow-flow vascular malformation in the infrapatellar region of the left knee. However, subsequent magnetic resonance imaging (MRI) revealed a well-defined mass in the subcutaneous plane below the knee, with minimal septations, leading to an initial suspicion of a large sebaceous cyst. Further investigation through histopathological analysis confirmed the diagnosis of an extra-articular schwannoma. This finding highlights the importance of thorough examination and diagnostic techniques in differentiating between various types of soft tissue masses. Schwannomas, although uncommon in certain locations, should be considered in the differential diagnosis of painful lumps, even in atypical anatomical sites such as the knee.

Ewing sarcoma of Hoffa fat pad in the knee: a case report and review of the literature on primary intraarticular sarcomas and Hoffa fat pad masses

Primary intraarticular sarcomas are rare. We describe a unique case of intraarticular Ewing sarcoma arising in Hoffa fat pad of knee in a woman. The patient was treated successfully with chemotherapy and left knee arthroplasty; however, the tumor recurred after 3 years.We review the literature on primary intraarticular sarcomas and Hoffa fat pad masses in the knee.

A Giant Ganglion Cyst Arising from Lateral Hoffa's Fat Pad of the Knee

Introduction

The ganglion cysts are benign fluid-filled sacs, which often arise from a tendon sheath or a joint capsule. Their origin from the fat pad of the knee is rare. Several studies have described intra-articular ganglion cysts in detail; however, extra-articular soft-tissue ganglion cysts have been reported sparingly. We report a rare case of giant ganglion cyst arising from lateral Hoffa’s fat pad (HFP).

Case Report

A 59-year-old male patient presented with a 3-year history of swelling of the left knee, with occasional pain. There was no history of trauma or any constitutional symptoms. There was an apparent swelling (10 cm ×5 cm in size) around the anterolateral aspect of the knee joint. A magnetic resonance imaging (MRI) scan revealed a multilobular, complex cystic lesion of the lateral HFP. Surgical excision of the cyst was done, and histopathological examination confirmed the diagnosis of the ganglion cyst.

Conclusion

Cysts and cystic-appearing lesions around the knee are not uncommon, but a ganglion cyst arising from HFP is rare. The presence of multipotent cells in the HFP may be responsible for producing a variety of cyst and cyst-like tumors around the anterior aspect of the knee joint. An MRI is the best imaging modality for the diagnosis of these cysts and cysts-like lesions around the knee. We recommend that the smaller intra-articular lesions can be resected arthroscopically, but larger lesions, with extraarticular extension, are best treated by open resection to avoid incomplete excision and recurrence.

Endoscopic Resection of Localized Pigmented Villonodular Synovitis in the Hoffa Fat Pad

Pathologies within the fat pad can have either intrinsic or extrinsic causes. Most of them are the consequences of trauma and degeneration, but inflammatory and neoplastic diseases can arise in the fat pad. Pigmented villonodular synovitis is the most common space-occupying lesion of the Hoffa fat pad, followed by ganglion. The purpose of this Technical Note is to describe the details of endoscopic resection of localized pigmented villonodular synovitis in the Hoffa fat pad. Hopefully, this can allow complete resection of the lesion with minimal surgical trauma and scar tissue formation.

Schwannoma: A Rare Hoffa's Fat Pad Tumor

Hoffa's fat pad can be affected by a variety of tumors. Schwannomas are benign and typically solitary neoplasms of the peripheral nerve sheath; they are made up of the neoplastic Schwann cells and are usually located eccentrically. Malignant schwannomas are extremely uncommon. Here we report a case of an intra-articular schwannoma of the knee. A 54-year-old man presented with a painful lump in the medial aspect of the knee. Magnetic resonance imaging revealed a well-circumscribed intra-articular mass, which was later diagnosed as an intra-articular schwannoma based on biopsy findings.

Ultrasonographic Morphological Changes in the Prefemoral Fat Pad Associated with Knee Osteoarthritis

Background

In normal knees, quadriceps contraction changes the shape of the prefemoral fat pad (PFP). However, in persons with knee osteoarthritis (OA), the functional or morphological changes of the PFP are unclear. This study aimed to clarify the morphological changes in the PFP in individuals with knee OA through ultrasonography.

Materials and Methods

Participants were divided into the OA (36 knees; mean age, 74 years), elderly (31 knees; mean age, 70 years), and young (26 knees; mean age, 21 years) groups. The anteroposterior (AP) length of the PFP before and during isometric quadriceps contraction at 0°, 30°, 60°, and 90° knee flexion was measured ultrasonographically. The difference between the maximum and minimum length values, change in length, was also measured. These parameters were compared among the three groups. In the OA group, correlations between the parameters and clinical features (knee pain; visual analog scale, knee range of motion [ROM], Kellgren and Lawrence (K/L) grade, and intercondylar distance) were examined by Spearman and Pearson's correlation coefficient tests.

Results

The AP lengths of the PFP before contraction were significantly lower in the OA group than in elderly group and young group at 30° (6.9 ± 2.5 vs. 12.0 ± 3.6 or 11.1 ± 2.7 mm, respectively; in order P = 0.014, P = 0.006) and 60° (6.5 ± 2.0 vs. 9.7 ± 2.5 or 9.1 ± 2.7 mm, respectively; both P < 0.001). The AP lengths of the PFP during contraction were significantly lower in the OA group than in elderly group and young group at 0° (6.7 ± 2.3 vs. 8.8 ± 3.7 or 9.1 ± 1.6 mm, respectively; both P < 0.001), 30° (7.9 ± 2.6 vs. 12.9 ± 3.7 or 13.0 ± 2.6 mm, respectively; both P < 0.001), and 60° (7.1 ± 2.5 vs. 13.5 ± 2.6 or 13.6 ± 3.0 mm, respectively; both P < 0.001). The change in length before maximum isometric quadriceps contraction was significantly lower in the knee OA group than in both elderly and young groups (3.3 ± 1.9 vs. 8.4 ± 2.5 or 6.8 ± 3.0 mm, respectively; both P < 0.001). The change in length during contraction was also significantly lower in the knee OA group than in both the elderly and young groups (3.9 ± 2.3 vs. 8.7 ± 2.3 or 8.9 ± 2.0 mm, respectively; both P < 0.001). In the OA group, change in length during contraction was significantly associated with knee pain (r = -0.476, P = 0.007), knee ROM (r = 0.388, P = 0.019), and Kellgren and Lawrence grade (r = -0.357, P = 0.045).

Conclusions

In knee OA, movement of PFP was decreased more than healthy participants. In the knee OA group, the decrease of the morphological change of the PFP showed the relationship between VAS score, knee extension ROM, intercondylar distance (ICD), and K/L grade. An evaluation to the PFP may be required in individuals with knee OA.

A Case of Infrapatellar Fat Pad Ganglion of the Knee

Introduction:

A ganglion cyst can induce symptoms around the knee and should be considered as an intra-articular mass in differential diagnosis.

Case Presentation:

A 22-year-old female presented with a persistent medial knee joint pain in her left knee for 2 years. There was soft tissue swelling on the anteromedial aspect of the infrapatellar region on her left knee. Lachman and McMurray tests were negative. MRI showed a multilobular cyst in the infrapatellar fat pad with T1 low intensity and T2 STIR high intensity. The cyst was not attached to either meniscus. ACL and PCL looked normal.

During surgery, the cyst was found to arise from the intra-patellar fat pad and was not attached to the menisci or synovium. The cyst was completely resected.

Histological findings showed a multilobular cyst with a glassy fibrous tissue wall and clear jelly-like consistency, confirming the diagnosis of a ganglion. The patient recovered asymptomatically and has been without recurrence 7 years postoperatively.

Conclusion:

Differential diagnoses of an infrapatellar swelling are a meniscal cyst, synovial cyst, or ganglion. Most cases of cysts around the knee generate from fluid collection through meniscal tears. A ganglion cyst is a synovium-lined structure and is common around the wrist joint, but rare in the knee joint. A ganglion cyst in the knee joint often arises from ACL or PCL, but rarely arises from the infrapatellar fat pad. A ganglion cyst is one of the differential diagnoses of parameniscal cysts around the knee. We recommended an open resection with arthroscopic examination.

Hoffa's fat pad tumours like: results of the arthroscopic resection

We performed a retrospective cohort study to increase awareness in orthopaedic community of this rare but interesting disease which is often misdiagnosed as meniscal pathology and to analyze present results of arthroscopic resection in seven patients. we retrospectively reviewed records from 2008-2012 and identified 7 patients with symptomatic Hoffa's fat pad impingement. The diagnosis was made by clinical exam, MRI imaging and verified arthroscopically. Of the 7 patients 2 were excluded due to receiving open resection. The remaining five underwent arthroscopic resection. Lysholm and American knee society scores were obtained pre and post operative and at final follow up. There was a significant improvement in their symptoms and function after the surgery at an average follow-up of 14 months. The one poor result was because of paresthesia over the distribution of the infrapatellar branch of the saphenous nerve after open resection. tumours like of the fat pad should be treated by arthroscopic resection because of less residual pain and less complication was found using arthroscopy. In case of high volume of tumours only open excision can provide complete excision.

The surgical treatment of anterior knee pain due to infrapatellar fat pad pathology: A systematic review

BACKGROUND

Anterior knee pain (AKP) encompasses a range of pathologies. As a result, there are a number of therapeutic options used to treat AKP. The non-operative treatments have been analysed in a number of randomised controlled trials and systematic reviews. There is however a scarcity of such publications covering the surgical management of AKP. There are no systematic reviews that have investigated surgical interventions for AKP due to pathology of the infrapatellar fat pad (IFP). The aims of this study were to review the literature systematically, to establish which surgical procedures have been used to treat IFP disease and to determine their efficacy.

METHODS

The review was conducted in accordance with the PRISMA reporting guidelines. A search of the literature was performed on 1st January 2014 using multiple databases including CENTRAL, MEDLINE, EMBASE, PubMed, and Google Scholar. The quality of the studies was assessed using Oxford Evidence-Based Medicine Levels of Evidence guidelines and the GRADE approach.

RESULTS

Twenty-four eligible studies were found and included. The critical appraisal identified that the current evidence-base has low methodology quality. The clinical findings indicated that there is a positive trend towards the surgical management of IFP disease for AKP symptoms. Excision of IFP tumours and resection of the IFP in Hoffa's disease can lead to improvements in symptoms and function.

CONCLUSIONS

Truly robust evidence to support the surgical management of IFP pathology requires randomised controlled trials; however the expenses involved to design such trials means that they are unlikely to be undertaken for this uncommon disorder. Consequently well-designed and well-reported case series need to be undertaken to improve our current understanding that includes recording quantitative measures such as range of knee motion, VAS Pain scores and a validated scoring system.

Treatment of pigmented villonodular synovitis of the knee

PURPOSE

We aimed to determine the rate of local recurrence, the rate of postoperative complications, and the functional outcome at final follow-up of surgical and nonsurgical treatment approaches for pigmented villonodular synovitis (PVNS) of the knee.

METHODS

Medline, Embase, and the Cochrane Library were systematically searched for studies that reported the results of treatment for any type of PVNS between January 1, 1950, and August 1, 2013. Two authors extracted the data independently using predefined data fields including study quality indicators.

RESULTS

Sixty studies (1,019 patients) met the inclusion criteria. Thirty-five presented data on the treatment of localized pigmented villonodular synovitis (LPVNS), 40 on diffuse pigmented villonodular synovitis (DPVNS), 1 on extra-articular LPVNS, and 7 on DPVNS with extra-articular involvement. Many therapeutic options were reported. Depending on these options, DPVNS recurred in 8% to 70% of the series and LPVNS recurred in 0% to 8% of the series. For LPVNS, the 2 most-reported options were open localized synovectomy and arthroscopic local synovectomy. Between these 2 courses of treatment, no difference was found in terms of local recurrence (8.7% for open synovectomy and 6.9% for arthroscopic synovectomy) and postoperative complications (<1% for open synovectomy and 0% for arthroscopic synovectomy). For DPVNS, the 2 most-reported options were open total synovectomy and arthroscopic total synovectomy. Between these 2 courses of treatment, no difference was found in terms of local recurrence (22.6% for open synovectomy and 16.1% for arthroscopic synovectomy). However, we found a lower rate of reported complications between open synovectomy (19.3%) and arthroscopic synovectomy (0%). Internal irradiation or external beam radiation as an adjuvant treatment to surgical synovectomy seemed to decrease the rate of local recurrence in DPVNS cases with a high risk of recurrence. Finally, we found a great heterogeneity in the way the functional results were reported, and no valid conclusion could be made based on the data we extracted.

CONCLUSIONS

We found no difference in local recurrence rates after open or arthroscopic surgery for either LPVNS or DPVNS. However, a lower rate of postoperative complications was reported after arthroscopic surgery for DPVNS.

LEVEL OF EVIDENCE

Level IV, systematic review of Level IV therapeutic studies.

Arthroscopic resection of fat pad lesions and infrapatellar contractures

The infrapatellar fat pad (IFP), also known as Hoffa's fat pad, may be a common site of pain in the knee because of its susceptibility to injury and its vast innervation and vascular supply. Patients who have trauma to the IFP may undergo a process of hemorrhage, inflammation, and fibrosis that may become painful. Patients with Hoffa's disease in whom conservative treatment with medications, physical therapy, and injections has failed may receive significant pain relief and benefit from undergoing arthroscopic subtotal removal of the IFP. We describe a safe and effective way to perform this procedure allowing excellent visualization through the use of a superolateral viewing portal.

Hoffa's fat pad tumours: what do we know about them?

PURPOSE

We report on a group of patients with tumours in the Hoffa's fat pad (HFP), their clinical presentation, histological type and treatment, including two synovial sarcomas with their clinical follow-up, which have not been described previously in the literature.

METHODS

We performed a retrospective review of our prospectively collected database of 25 cases of HFP tumours with at least six months follow-up.

RESULTS

The gender, age at presentation (over and under 16 years of age), clinical features, history of trauma, treatment chosen, and complications were recorded. The mean age of the patients was 32 years (three to 47). Six patients were under 16 years old. Pain was the most common symptom, present in 92% (n = 23/25). The final diagnoses included 23 (92%) benign tumours and two (8%) malignant tumours. The most common benign tumour was pigmented villonodular synovitis (PVNS) (48% n = 12). The two malignant tumours were synovial sarcomas and both presented in patients under 16 years old.

CONCLUSIONS

Hoffa's fat pad tumours are an uncommon and rarely diagnosed group of lesions that can be misinterpreted as any knee pathology. Although the majority of HFP tumours are benign, malignant tumours should be considered in the differential diagnosis for the paediatric population.

MR imaging of anterior knee pain: a pictorial essay

Anterior knee pathology is a frequent cause of joint pain and limitation of function and mobility among patients presenting to an orthopaedic department. Proper recognition and treatment of pathologic conditions depend on the knowledge of normal anatomy and of the various abnormalities, which affect this area of the knee and may present with anterior knee pain. A broad array of benign and malignant processes may be manifested as anterior knee discomfort, and this common clinical entity is among the most frequent indications for MR imaging of the lower extremities. Clinical history and physical examination are also of paramount importance. The disorders can be categorized and differentiated primarily according to their location. Traumatic or non-traumatic disorders of the patella, patellar retinacula, quadriceps and patellar tendons and supra or infrapatellar fat pad can be the source of symptoms. This article includes a comprehensive pictorial essay of the characteristic MR features of common and uncommon disorders causing anterior knee pain. For accurate assessment of the aforementioned clinical problem, a radiologist should be able to identify typical MR imaging patterns that contribute in establishing the correct diagnosis and thus tailoring the appropriate therapy. Level of evidence IV.