A Case of Spontaneous Osteonecrosis of the Knee with Early and Simultaneous Involvement of the Medial Femoral Condyle and Medial Tibial Plateau.

Shinya Fujita,Shuji Nakagawa,Kuniaki Honjo,Toshikazu Kubo,Yuji Arai

doi:10.1155/2016/2574975

Shinya Fujita, Shuji Nakagawa + Show 3 more

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https://doi.org/10.1155/2016/2574975

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Abstract

Spontaneous osteonecrosis of the knee (SPONK) usually involves a single condyle, most often the medial femoral condyle (MFC). Involvement of the medial tibial plateau (MTP) is less common, occurring in about 2% of knees with SPONK. Early onset SPONK on the ipsilateral side of the medial compartment is very rare, with, to our knowledge, only four cases reported to date. We describe a very rare case of SPONK with early simultaneous development in the MFC and MTP. Serial plain radiographs and magnetic resonance imaging showed that SPONK in both condyles followed a similar progressive course. The pathological findings in these lesions were similar to those observed in subchondral insufficiency fractures.

Highlights

Osteonecrosis of the knee can be categorized as primary spontaneous osteonecrosis of the knee (SPONK) [1] or secondary osteonecrosis of the knee associated with a variety of risk factors including use of steroids or alcohol [2, 3]
Secondary osteonecrosis is usually observed in younger patients and involves multiple condyles, whereas SPONK usually develops suddenly in the medial femoral condyle (MFC) of patients aged >55 years [4]
The etiology of SPONK remains unclear, it may be due to vascular injury and/or antecedent trauma [8,9,10,11,12], a recent report suggested that SPONK may result from subchondral insufficiency fractures [10]

Summary

Introduction

Osteonecrosis of the knee can be categorized as primary spontaneous osteonecrosis of the knee (SPONK) [1] or secondary osteonecrosis of the knee associated with a variety of risk factors including use of steroids or alcohol [2, 3]. Secondary osteonecrosis is usually observed in younger patients and involves multiple condyles, whereas SPONK usually develops suddenly in the medial femoral condyle (MFC) of patients aged >55 years [4]. Involvement of the MTP is observed in only 2% of knees with SPONK [6, 7], whereas early concomitant involvement of the MFC and the adjacent MTP is very rare. Magnetic resonance imaging (MRI) can detect early changes in the subchondral area and assist in the diagnosis of SPONK. This report describes a very rare case of SPONK simultaneously involving the MFC and the MTP and associated with subchondral insufficiency fractures. This condition was diagnosed on MRI soon after symptom onset

Case Report

Discussion

Findings

Conclusion