A Special Tear Pattern of Anterior Horn of the Lateral Meniscus: Macerated Tear

Abstract

BackgroundWe describe a special, interesting phenomenon found in the anterior horn of the lateral meniscus (AHLM): most tear patterns in the AHLM are distinctive, with loose fibers in injured region and circumferential fiber bundles were separated. We name it as macerated tear. The goal of this study was to bring forward a new type of meniscal tear in the AHLM and investigate its clinical value.Materials and MethodsAHLM tears underwent arthroscopic surgery from January 2012 to December 2014 were included. Data regarding the integrity of AHLM were prospectively recorded in a data registry. Tear morphology and treatment received were subsequently extracted by 2 independent reviewers from operative notes and arthroscopic surgical photos.ResultsA total of 60 AHLM tears in 60 patients (mean age 27.1 years) were grouped into horizontal tears (n = 15, 25%), vertical tears (n = 14, 23%), complex tears (n = 6, 10%), and macerated tears (n = 25, 42%). There were 6 patients with AHLM cysts in macerated tear group and one patient in vertical tear group. 60 patients were performed arthroscopic meniscus repairs and were followed-up with averaged 18.7 months. Each group had significant postoperative improvement in Lysholm and IKDC scores (p < 0.05). However, the macerated tear group showed least functional recovery of Lysholm and IKDC scores compared to other groups (p < 0.05). In addition, there were no differences in postoperative range of motion, return to work, or return to sport/other baseline activities between the four groups (p > 0.05).ConclusionsThis study demonstrated that the macerated tear is common in the tear pattern of AHLM. However, feasibility of the treatment of this type of meniscal tear, especially the meniscus repairs still requires further study.

Clinical and Radiological Outcomes After Isolated Anterior Horn Repair of Medial and Lateral Meniscus at 24 Months’ Follow-up, With the Outside-In Technique

“…Anterior horn meniscal injury is a rare entity and only three case series with small samples have been previously published, focusing on lateral meniscus [ 8 , 18 , 22 ]. Choi et al used all-inside technique in seven young male footballers, with return to sport at six months after surgery.…”

“…Hagino et al reported great improvement in mean Lysholm score 12 months postoperatively, similar to our results in 8 young male footballers with anterior horn tears of the lateral meniscus, although treatment modality was not consistent (only two tears were repaired, the rest were partially excised) [ 8 ]. In the study by Zhen et al which focused on anterior horn tears of the lateral meniscus, patients with anterior horn tears were organized based on tear morphology [ 18 ]. The macerated tear type was present in the majority of patients (42%), the other three being horizontal tears, vertical tears or complex tears.…”

“…Moreover, another group was studied with preoperative anterior horn cysts, that showed even worse patient-reported outcomes. At the last follow-up (range 15-36 months), Lysholm and IKDC scores were 84.4 (range, 78-90 points) and 80.3 points (range 74-90 points), respectively, for patients with macerated type of tear [ 18 ]. Recently, it was reported that patients who underwent acute meniscal repair (<6 weeks from injury) demonstrated significantly higher improvements on the Tegner activity scale and Lysholm score compared with patients treated beyond six weeks from injury, regardless of the meniscal tear zone, at a minimum follow-up of two years.…”

“…Therefore, surgical repair of meniscal lesions is indicated whenever possible [ 24 ]. On the other hand, optimal treatment of the macerated, degenerative-like tears in the anterior horn remains unclear, due to poorer patient-reported outcomes and questionable mechanical integrity of meniscal repair [ 18 ]. Latest research does not support the previous hypothesis that younger age at the time of meniscal repair would result in fewer failures [ 11 ].…”

Traumatic avulsion of the anterior medial meniscus root combined with PCL injury: a case report

“…When the flexion angle is less than 30°, the anterior medial meniscus horn withstands a high shear strength and prevents the femur from antedisplacement [9,10]. PCL can prevent retrodisplacement of the tibia [11], meanwhile, the anterior medial meniscus horn can prevent antedisplacement of the femur [12], the two coordinately prevent the excessive motion of the knee joint. In our case, however, the PCL couldn't bear the tension caused by the excessive motion of the knee joint, and thus a high shear was exerted to the anterior medial meniscus horn, leading to traumatic avulsion of the AMMR complicated with PCL injury.…”