Extrusion of the medial meniscus is a potential predisposing factor for post-arthroscopy osteonecrosis of the knee

Jun Yamaguchi,Jun Onodera,Norimasa Iwasaki,Tomonori Yagi,Koji Yabuuchi,Kazunori Yasuda,Daisuke Ueda,Takuma Kaibara,Mitsuru Saito,Eiji Kondo

doi:10.1186/s12891-021-04730-7

Abstract

BackgroundPost-arthroscopic osteonecrosis of the knee (PAONK) is a rare condition. No studies have analyzed the relationship between the meniscus extrusion and PAONK. The purpose of this retrospective study is to test a hypothesis that the degree of the medial meniscus (MM) extrusion might be significantly greater in the knees with PAONK than in the matched control knees both before and after the meniscectomy.MethodsTen knees with PAONK were detected out of a total of 876 knees which had undergone arthroscopic partial meniscectomy of the MM. Ten matched control knees were randomly selected out of the remaining 866 knees without PAONK. The clinical data of these 20 patients were retrospectively collected from the medical records. To evaluate the location of the menisci on the joint line, Extrusion width and Inner width were defined on a coronal section of magnetic resonance imaging (MRI). The intra- and inter-rater reliability was evaluated by calculating the intra- and inter-class coefficients. Statistical comparisons between the 2 groups were made using the 3 non-parametric tests.ResultsBefore the meniscectomy, the Extrusion width of the MM (mean 4.7 ± 1.4 mm) was significantly greater than that (3.0 ± 1.3 mm) in the Control group (P = 0.0195). In the MRI taken in a range from 3 to 50 weeks after the meniscectomy, the Extrusion width of the MM (5.9 ± 1.1 mm) in the PAONK group was significantly greater than that (3.4 ± 1.4 mm) in the Control group (P = 0.0009), and the Inner width of the MM (0.6 ± 1.7 mm) in the PAONK group was significantly less than that (3.9 ± 1.0 mm) in the Control group (P = 0.0001).ConclusionA significant relationship was found between the degree of the MM extrusion and the onset of PAONK. This study suggested that the extrusion of the MM is a potential predisposing factor for PAONK.

Highlights

Post-arthroscopic osteonecrosis of the knee (PAONK) is a rare condition
The major requirement in diagnosing PAONK is to confirm that any evidence of any evidence of bone marrow edema (BME) or osteonecrosis was absent in the magnetic resonance imaging (MRI) taken immediately before the meniscectomy [2]
PAONK was diagnosed with MRI examinations using the following criteria [2, 20]: (1) The patient complained of serious knee pain within 12 months after arthroscopic meniscectomy

Summary

Introduction

Post-arthroscopic osteonecrosis of the knee (PAONK) is a rare condition. No studies have analyzed the relationship between the meniscus extrusion and PAONK. PAONK is a rare condition so that the incidence has been reported to be 0.2–1.5% of the knees which underwent arthroscopic surgery [5, 6]. There is a high probability that a significant relationship exists between the meniscal extrusion and the onset of PAONK. The present study was conducted to analyze the relationship between the meniscal extrusion and the onset of PAONK. Out of 876 knees which had undergone arthroscopic partial meniscectomy of the medial meniscus (MM), 10 knees with PAONK were detected (PAONK group). From the remaining 866 knees, in which PAONK did not occur after partial meniscectomy, the authors randomly selected 10 matched control knees. The meniscus location on the joint line in the PAONK group was compared with that in the Control groups

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