Anterior Mobility of the Posterior Horn of the Lateral Meniscus Is Associated With Abnormal Magnetic Resonance Imaging Findings of Anteroinferior Popliteomeniscal Fascicle and Posterosuperior Popliteomeniscal Fascicle as Well as a Clinical History of Catching or Locking Symptoms

Abstract

PurposeWhen symptoms caused by hypermobility of the posterior horn of the lateral meniscus (PHLM) emerge, it is difficult to know which restraints should be treated. To identify predictors of anterior mobility of the PHLM among patient demographics (age, sex), clinical characteristics (a history of catching or locking symptoms [CLS], body mass index, alignment of limb), and magnetic resonance imaging (MRI) findings of four restraints (anteroinferior popliteomeniscal fascicle [aiPMF], posterosuperior popliteomeniscal fascicle [psPMF], posteroinferior popliteomeniscal fascicle [piPMF], meniscofibular ligament [MFibL]). MethodsBetween October 2010 and December 2014 patients who underwent arthroscopic measurement of mobility of the PHLM were identified. The Sakai classification was used to classify aiPMF and psPMF on MRI into the following three types: type A, the fascicle was depicted with obvious continuity and with a low-intensity band; type B, depicted with continuity but with an ambiguous intensity structure; and type C, depicted with discontinuity or not visible. Magnetic resonance images of the piPMF and MFibL were evaluated as presence or absence. The mobility of the PHLM was measured arthroscopically at traction forces of 10 and 20 N. ResultsA total of 73 patients (47 men, mean age 41.8 ± 19.3 years) were included. Multivariate regression analyses revealed aiPMF type C and psPMF types B and C to be independent factors associated with mobility at both traction forces, and CLS was an independent factor at a traction force of 20 N. Compared with that of type A, the increased mobility of aiPMF type C was 5.0 mm (P = .019) and 5.6 mm (P = .011) at 10 and 20 N, respectively, the increased mobility of psPMF type B was 2.5 mm (P = .007) and 3.5 mm (P = .0003), respectively, and the increased mobility of psPMF type C was 3.3 mm (P = .021) and 3.6 mm (P = .014), respectively. The increased mobility associated with CLS was 3.5 mm at 20 N (P = .022). ConclusionsAnterior displacement of the PHLM induced by an external traction force at 90-degree flexion of the knee joint was associated with abnormal MRI findings of anteroinferior popliteomeniscal fascicle and posterosuperior popliteomeniscal fascicle, and a history of catching or locking symptoms. Clinical RelevanceUnderstanding signs and symptoms and associated pathology in patients with symptomatic anterior mobility of the posterior horn of the lateral meniscus may help guide best treatment.