Hypermobile Anterior Horn of the Lateral Meniscus: A Case Report and Literature Review

Abstract

Hypermobile meniscus is known as one of the causes of knee pain and locking or limitation of the range of motion during knee flexion, even when there is no evidence of meniscus tear on magnetic resonance imaging (MRI). Most such cases show excessive hypermobility of the posterior part of the lateral meniscus. This case report presented a rare case of a hypermobile anterior horn of the lateral meniscus. An 18-year-old woman visited our hospital for left knee pain without trauma. Her physical examination showed a limited range of motion and tenderness in the lateral joint space. However, her MRI did not show any abnormalities. After conservative treatment failed, we performed arthroscopic surgery. The arthroscopic evaluation showed no meniscus and no other intraarticular injury. However, the anterior horn of the lateral meniscus was easily translated beyond the lateral condyle by using a probe. Thus, hypermobile anterior horn of the lateral meniscus was diagnosed. The meniscus was stabilized by the outside-in technique. Immediately after surgery, the catching symptom and pain were alleviated. After three-and-a-half months, she returned to work. The Lysholm score improved from 55, preoperatively, to 100, 1-year postoperatively. In conclusion, careful arthroscopic evaluation is essential for the diagnosis of a hypermobile anterior horn of the lateral meniscus. Arthroscopic meniscus stabilization provides a good outcome for hypermobile meniscus.

Hypermobile lateral meniscus: A systematic review of current treatment options

“…As presented in Figure 1, the process of study selection started with the identification of 213 possibly relevant articles from three distinct databases (52 studies from PubMed, 70 from Scopus, 29 from Web of Science, 62 from Embase), in addition to 10 studies retrieved from the manual search of the included studies' references. In the next step, after removing the duplicate records, 93 articles underwent initial screening based on their title and abstract, of which 58 studies were excluded and the rest of the studies were evaluated for full‐text eligibility, which led to the exclusion of 15 other articles for the following reasons: five technical notes [10, 39, 44, 46, 50], eight articles for having a study population other than interest (LM tear, Wrisberg type of LM or injury in other PLC structures) [6, 9, 13–15, 27, 30, 32], one study for not mentioning the treatment [45], and one study [54] for having the same population with an included article by Zheng et al [53]. Eventually, 20 studies were included for the qualitative synthesis [3, 8, 11, 12, 17, 19, 22, 24, 29, 31, 33–35, 40–43, 49, 53].…”

Guidelines on the Diagnosis and Treatment of Lateral Meniscal Lesions: A Consensus Statement by the Chinese Society of Sports Medicine

“…In addition, hypermobility of the anterior horn causes anterior knee pain even without MRI evidence of a meniscal tear. 154 Therefore, a comprehensive sports activity history should be taken in combination with physical examination, including Beighton score 154 and MRI, during the clinical workup.…”

Permanent Subluxation of the Lateral Meniscus in a 10-year-old Boy: A Case Report with Short Literature Review

“…There are very few case series or cases reported in literature attributing atraumatic knee locking to non-discoid lateral meniscus pathology [ 1 , 7 , 10 ]. The pathoanatomic features in our case painted a picture of congenital or developmental malformation rather than a tear.…”

“…The posterior part of the lateral meniscus is the culprit in most of the cases due to disruption of the popliteo-meniscal fascicles near the popliteal tendon [ 3 - 6 ]. A solitary case of hypermobile lateral meniscus due to the anterior horn has also been reported [ 7 ]. In contrast, the MRI of our patient showed a displaced bucket handle lateral meniscus tear resembling the flipped meniscus sign described by Haramati et al [ 11 ].…”

“…Patients with hypermobility present with knee pain with or without locking, and the characteristic feature is an intact meniscus with abnormal mobility when probed [ 3 ]. The posterior segment of the lateral meniscus is the culprit in most cases, although a solitary case attributing hypermobility to the anterior segment has been reported [ 3 - 7 ].…”