Ossification of the discoid meniscus: A case report

Abstract

Discoid OssificationMagnetic resonance imaging a b s t r a c t Meniscal ossification, or bone formation within the substance of the meniscus, is a rare entity. Magnetic resonance imaging allows the unequivocal diagnosis of a meniscal ossification. We aimed to present a case of discoid meniscal ossification, which is quite rare, with the emphasis on imaging findings.Copyright © 2014, Delhi Orthopaedic Association. All rights reserved. IntroductionMeniscal ossification is mature lameller and cancellous bone containing fatty bone marrow surrounded by hyaline cartilage within the substance of meniscus. 1e3 Discoid meniscal ossification is exceedingly rare. Imaging is required to confirm the diagnosis and to assess the meniscal integrity. Standard radiographs and magnetic resonance imaging (MRI) have been reported useful in the diagnosis of meniscal ossification. 4 We aimed to present a case of discoid meniscal ossification with the emphasis on imaging findings. Case reportA 42-year-old women presented with pain in the left knee joint lasting for nine months. The pain was intermitten in nature. There was no history of recent trauma or any other relevant past history. Physical examination showed a moderately painful swollen joint without any restriction of movement. Upon admission, no pathological findings were found at the patellofemoral joint or periarticular ligamentous structures on the physical examination. The plain radiographs obtained a wedge-shaped, like the meniscus, bony fragment at the lateral side of the knee joint (Fig. 1). MR imaging of this knee was performed to evaluate the ossific density. A well-defined lesion which was seen in the discoid lateral meniscus was isointense to the bone marrow on all pulse sequences, with a complete hypointense rim (Fig. 2aed). The lesion size was 36*30*6.5 mm. This was reported as a meniscal ossification. The articular cartilage was also normal. Mild synovial effusion was detected. In addition, a simple cyst of the proximal fibula was detected. Available online at www.sciencedirect.com ScienceDirect j o urna l h om epag e: www.elsevier.com /locate/jcot j o u r n a l o f c l i n i c a l o r t h o p a e d i c s a n d t r a u m a 5 ( 2 0 1 4 ) 2 7 0 e2 7 3http://dx

Systemic versus local adipokine expression differs in a combined obesity and osteoarthritis mouse model

“…Interestingly, ossification of menisci was observed in some animals, which was comparably described in case reports in patients 48 – 51 . The molecular mechanisms involved in ossicle formation are not well known.…”

Understanding the Implications of the Meniscal Ossicle: Patient Presentation, Treatment, and Outcomes

“…As has been previously suggested in the literature, the vast majority of patients who were identified as having a meniscal ossicle presented with knee pain localizing to the joint compartment containing the ossicle. 7,9,11 This is likely due to the finding in this study that the ossicle is closely associated with a mensicus root tear. Meniscus root tears are particularly detrimental in that the ability to maintain hoop strain, when the tibiofemoral joint is loaded, is impaired.…”

“…[4][5][6] and currently the most popular theory of origin is that the ossicle is the result of a prior single or repetitive traumatic event. 3,9 Numerous case reports have been published on this topic, while a limited number of studies have been performed with the largest being a case series by Mohankumar et al in which they assessed 65 knee MRI examinations and described the location of the ossicle within the meniscus as well as associated imaging findings of the knee. 3 To our knowledge, this article is the first case series to describe the clinical presentation, management, and outcomes of patients identified with a meniscal ossicle.…”

“…8 In humans, the current prevailing theory is that of posttraumatic origin. 3,9 Prior studies have described meniscotibial avulsion from the root of the meniscus following trauma to the knee. 10,11 Other studies have described cartilaginous ossification caused by metaplasia of fibrous cartilage following the irregular neovascularization of connective tissue as a result of trauma.…”

“…This theorized traumatic etiology, either repetitive microtrauma or an acute injury, subsequently reverts the connective tissue to the embryonic state, which is more vulnerable to calcareous deposition and ossification. 2,3,7,9,12 Currently, there is limited information regarding the meniscal ossicle, and much of the available literature consists of case reports. In a study assessing 65 knee MR examinations with meniscal ossicles, Mohankumar et al showed that the vast majority of ossicles (89%) were located in the medial meniscus and that 95% of the ossicles they identified were located in the posterior horn or root of the meniscus.…”