2015 ISAKOS Biennial Congress ePoster #1614

Postoperative Deformation of the Discoid Lateral Meniscus After Partial Meniscectomy With Repair

Tomohiko Matsuo, MD, PhD, Hirakata, Osaka JAPAN
Kazutaka Kinugasa, MD, PhD, Sakai, Osaka JAPAN
Kenji Yoneda, MD, Osaka JAPAN
Masayuki Hamada, MD, Sakai, Osaka JAPAN

Hoshigaoka Medical Center, Hirakata, Osaka, JAPAN

FDA Status Not Applicable

Summary: The discoid lateral meniscus exhibited size reduction and extrusion from 2 weeks to 6 months after partial meniscectomy with repair.

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Abstract:

Introduction

Recent studies have shown that a symptomatic discoid lateral meniscus (DLM) with peripheral tear was successfully treated with partial meniscectomy with repair. However, whether the function of load transmission of the postoperative meniscus is maintained or not is unclear. The purpose of this study was to investigate the morphology of DLM after partial meniscectomy with repair using magnetic resonance imaging (MRI) in order to evaluate the remaining function of the meniscus.

Methods

Seven patients with symptomatic DLM with peripheral tear participated in this study. There were 4 males and 3 females. Their age ranged from 10 to 17 years, with a median of 12 years. We obtained informed consent from all subjects, and appropriate institutional review board for human subject research approved this study.
All of 7 patients underwent partial meniscectomy with repair. MRI examination was performed before weight bearing (2 weeks after surgery) and at resumption of sports (6 months after surgery) using 1.5-Tesla MR scanner. First, the widths of anterior and posterior segments were measured in the sagittal slice, and that of middle segment was in the coronal slice. Second, the distance between anterior (posterior) edge of DLM and that of tibia was measured in the sagittal slice, and the distance between lateral edge of DLM and that of tibia was in the coronal slice. Positive values indicated that DLM existed inside of the tibial plateau, whereas negative values denoted the extrusion of DLM. The Wilcoxon signed rank test was used and differences were considered significant at P < 0.05.

Results

Six months after surgery, all patients had no pain, exhibited a full range of motion, and were able to return to their previous sporting activities. Widths of anterior, middle, and posterior segments significantly decreased from 2 weeks (12.7 ± 2.7 mm, 11.2 ± 4.0 mm, and 10.9 ± 2.4 mm) to 6 months (10.5 ± 3.1 mm, 6.7 ± 3.6 mm, and 8.8 ± 2.4 mm) after surgery. Distances of anterior and middle segments significantly decreased from 2 weeks (8.4 ± 4.2 mm and 1.1 ± 1.3 mm) to 6 months (4.3 ± 2.1 mm and -1.3 ± 1.3 mm) after surgery, indicating anterior and lateral shift. On the other hand, the distance of posterior segment showed no significant change.

Discussion

The most important finding of this study was that DLM exhibited size reduction and extrusion from 2 weeks to 6 months after partial meniscectomy with repair. The reason of this finding was probably that the remaining DLM could not effectively resist the hoop stress generated by weight bearing. Even if clinical results are good, the function of load transmission may not be maintained appropriately. Therefore, longer follow-up should be needed to evaluate the risk of late osteoarthritis.