Discoid lateral meniscus: importance, diagnosis, and treatment

Abstract

Discoid lateral meniscus (DLM) is a common anatomic variant in the knee typically presented in young populations, with a greater incidence in the Asian population than in other populations. As DLM is a congenital anomaly, the ultrastructural features and morphology differ from those of the normal meniscus, potentially leading to meniscal tears. Snapping and pain are common symptoms, with occasional limitations of extension, in patients with DLM. Examination of the contralateral knee is necessary as DLM affects both knees. While simple radiographs may provide indirect signs of a DLM, magnetic resonance imaging (MRI) is essential for diagnosis and treatment planning. Although DLM was traditionally classified into three categories, namely, complete, incomplete, and Wrisberg DLM, a recent MRI classification provides useful information for surgical planning because the MRI classification was based on the peripheral detachment in patients with DLM, as follows: no shift, anterocentral shift, posterocentral shift, and central shift. Asymptomatic patients require close follow-up without surgical treatment, while patients with symptoms often require surgery. Total or subtotal meniscectomy, which has been traditionally performed, leads to an increased risk of degenerative arthritis; thus, partial meniscectomy is currently considered the treatment of choice for DLM. In addition to partial meniscectomy, meniscal repair of peripheral detachment is recommended for stabilization in patients with DLM to preserve the function of the meniscus. Previous studies have reported that partial meniscectomy with or without meniscal repair is effective and shows superior clinical and radiological outcomes to those of total or subtotal meniscectomy during the short- to long-term follow-up. Our preferred principle for DLM treatment is reduction, followed by reshaping with reference to the midbody of the medial meniscus and repair as firm as possible.

Examination of refractory discoid lateral meniscus injury

“…Furthermore, the use of fibrin clot augmentation has been described in the literature, particularly in cases exhibiting concurrence of horizontal or transverse tear. 12 In this study, even if meniscal displacement was observed, localized peripheral longitudinal tears tended to be repairable, while those with peripheral tears covering the entire meniscus and those with severe defects or tears in the body of the meniscus tended to be difficult to repair. In terms of postoperative outcomes, in addition to subtotal meniscectomy, those with residual peripheral rim of 5 mm width or less and those that cannot maintain the hoop function of the meniscus have been reported to show predisposition to concurrent degenerative changes or OCD.…”

“…11 Therefore, when there is a considerable defect in the popliteal hiatus of the DLM and reduction with a probe is unachievable, subtotal menisectomy is considered as a viable option, albeit with reluctance. 12 In addition, those with displacement are prone to require subtotal meniscectomy than those without displacement, and among those with displacement, the central shift type has been reported to most commonly require subtotal menisctomy. 9 In this study, when the meniscal body was The Lysholm score improved from a mean of 65.4 points preoperatively to 95.2 points postoperatively in all cases.…”

Wide Variability of Pediatric Knee Arthroscopy Case Volume in Orthopaedic Surgery Residency

“…3 Expansion of this field is developing fast, thanks to advancements in arthroscopic technology, increasing surgeon comfortability, and growing knowledge of child joint pathology. 4 While knee arthroscopy is used in children and adolescents to treat intra-articular fractures, 5 osteochondritis dissecans, 6 discoid lateral meniscus, 7 and synovitis, 8 the most common indications include sport injuries of the meniscus and ACL. 9 The incidence of acute and overuse sport injuries in pediatric athletes is at an all-time high, given the rise in sport participation.…”

Multivariate ordered logistic regression analysis of the postoperative effect of symptomatic discoid lateral meniscus

“…The discoid meniscus has an abnormal shape and structure. The disintegration of the circular collagen fibre system in the discoid meniscus matrix may be responsible for the higher tear rate and higher degeneration of the discoid meniscus compared to the normal meniscus [ 1 ]. Clinically, compared with the discoid medial meniscus, discoid lateral meniscus (DLM) is the most common, with a high prevalence in Asian populations (16–20%) [ 2 , 3 ]; and bilateral DLM accounts for 79–97% [ 4 ].…”

“…Symptomatic DLM is characterized by pain, swelling, snapping, locking, knee instability and limited mobility [ 5 ], which is mainly diagnosed by magnetic resonance imaging (MRI) and treated by arthroscopic surgery [ 3 , 6 ]. Although the overall postoperative outcomes of symptomatic DLM are acceptable [ 1 , 5 , 7 , 8 ], the outcomes between individuals are still largely different, which may result from diversity in patient’s characteristics and treatments [ 6 ]. Currently, studies have reported the influencing factors of postoperative arthroscopy for symptomatic DLM, but the results are inconsistent possibly resulted from differences in sample size, studied factors, and knee function evaluation system, etc.…”