Sifa Medical Journal

CASE REPORT
Year
: 2015  |  Volume : 2  |  Issue : 3  |  Page : 69--71

Ganglion cyst of the Hoffa's fat pad of the knee joint


Rahul R Bagul, Vivek Savaskar, Rohit Malhotra, Sachin Patel 
 Department of Orthopaedics, Padmashree Dr. Dnyandeo Yashwantrao Patil Medical College, Hospital and Research Centre, Dr. Dnyandeo Yashwantrao Patil Vidyapeeth, Pimpri, Pune, Maharashtra, India

Correspondence Address:
Dr. Rahul R Bagul
Department of Orthopaedics, Padmashree Dr. Dnyandeo Yashwantrao Patil Medical College, Hospital and Research Centre, Dr. Dnyandeo Yashwantrao Patil Vidyapeeth, Pimpri - 411 044, Pune, Maharashtra
India

Abstract

We report a rare case of ganglion cyst of Hoffa«SQ»s fat pad of knee joint. These lesions are asymptomatic in most cases and are often misdiagnosed as meniscal or ligamentous lesions of the knee joint. The final diagnosis was done with magnetic resonance imaging (MRI) of the knee joint, and the lesion was treated with surgery. It was not possible to resect the lesion through arthroscope, so open resection and complete excision of the cyst was done.



How to cite this article:
Bagul RR, Savaskar V, Malhotra R, Patel S. Ganglion cyst of the Hoffa's fat pad of the knee joint.Sifa Med J 2015;2:69-71


How to cite this URL:
Bagul RR, Savaskar V, Malhotra R, Patel S. Ganglion cyst of the Hoffa's fat pad of the knee joint. Sifa Med J [serial online] 2015 [cited 2020 Jun 6 ];2:69-71
Available from: http://www.imjsu.org/text.asp?2015/2/3/69/166867


Full Text

 Introduction



Ganglion cysts within the knee cavity are rare, and usually originate from the cruciate ligaments, the menisci, Hoffa's fat pad (HFP), [1] the popliteus tendon, and from osteochondral fractures or subchondral bone cysts. [2] A ganglion is a cystic swelling that is formed of myxoid matrix, which gives the ganglion a jelly-like consistency, and is lined with a pseudomembrane. Many of these lesions are incidental findings on magnetic resonance imaging (MRI) or arthroscopy, and usually are asymptomatic.

 Case Report



A 35-years-old female presented with increasing left knee pain since 12 months, which started after trauma to the knee. Immediately after trauma there was no swelling and the patient was able to walk. But she was disabled due to repeated attacks of knee pain. On clinical examination, there was a small infrapatellar cystic swelling in the anteromedial region, which increased during flexion of the knee and decreased with extension of the knee. There was no collateral and cruciate ligament laxity and McMurray's test was negative. There was no joint effusion and range of movements was terminally restricted and was painless in all directions. X-ray of left knee joint and hematological parameters were both normal. MRI showed well-defined lobulated lesion which was of low signal intensity in T1-weighted images and of high signal intensity in T2-weighted images arising from HFP, suggestive of ganglion cyst arising from it that was extending inside the knee joint [Figure 1] and [Figure 2]. Arthroscopic examination was done, but it was not possible to resect the lesion through arthroscope, so open resection and complete excision of the cyst was done. The mass was approached by an incision over the cystic mass medially to the patellar tendon. A multilobular mass of 6 cm was found inside the infrapatellar fat pad with a firm attachment to the capsule [Figure 3]. A very careful dissection of the whole mass along with a portion of the capsule was performed [Figure 4], and a substantial synovial defect was left. The defect was repaired, and the wound was closed in layers. A histological examination of the resected mass confirmed the diagnosis of ganglionic cyst. At 1-year follow up, the patient is completely asymptomatic with full painless range of movements.{Figure 1}{Figure 2}{Figure 3}{Figure 4}

 Discussion



A ganglion cyst may be seen in all joints with varying frequency depending on the location, but it is rare in the knee joint. [3],[4] The reported prevalence of ganglia in the knee joint are from 0.2 to 1% on knee MRI and 0.6% on knee arthroscopy. [5] Many cases of ganglia, ranging in size from 1.8 to 4.5 cm, have been reported, [6] and occasionally they are bilateral. Most of them are incidental findings and there are no symptoms. The first knee joint ganglion was described by Caan [7] in 1924, and there have been several references to ganglia around the knee since then. Brown and Dandy [8] reported 38 knee joint ganglia in 6,500 knee arthroscopies and half of the patients had no other abnormality. Ganglion cysts of the knee joint usually originate from lateral meniscus or anterior cruciate ligament or posterior cruciate ligament, but they rarely arise from HFP and only a few cases have been reported in the literature. [4],[9] The infrapatellar fat pad, known as HFP, is located posterior to the patellar ligament and adjoining capsule separating them from the synovium. The differential diagnoses of swelling in the infrapatellar fat pad region are lipoma, synovial cyst, meniscal cyst, and ganglion. Ganglion cysts do not have a fixed set of common symptoms, and their symptoms correlate with size and location within the knee joint. [10] The symptoms are; knee pain, clicks, stiffness, incomplete extension of the knee, pain at the extremes of motion, a palpable mass on knee flexion. Investigation includes X-ray knee joint to exclude pathologies such as a loose body or other bone abnormalities. MRI is the most sensitive, specific, accurate, and noninvasive method for diagnosing size and location of cystic masses. In addition, MRI also helps to exclude neoplastic lesions and to detect other intra-articular pathologies. [11] A variety of treatment modalities have been employed to treat ganglion cysts of HFP of the knee joint. Spontaneous reduction in size has been reported. [12] Excellent results with percutaneous aspiration using ultrasound and CT guidance have also been obtained. [13] Arthroscopic excision of intra-articular cysts [14],[15] has been reported, but the recurrence of ganglia after arthroscopic treatment has been reported. [16] In such cases, the recurrence risk is high and the patients should be followed-up more carefully. [17] When an open procedure has been decided, the preservation of an intact synovium should be the main consideration of the surgeon. Unfortunately, in our patient, the preservation of an intact synovium was not possible because the lesion was firmly attachment to the capsule. Our decision to carry on with an open excision of the ganglion cyst was for a complete resection of the cyst in order to decrease the recurrent rates and less on avoiding synovium invasion. The substantial defect of the synovium that was left after complete resection of the ganglion was repaired and the wound was closed in layers. At 1-year follow up, the patient is completely asymptomatic with full painless range of movements.

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