CASE REPORT

Severe bone defects and reduced mineralization caused by massive metallosis after total knee arthroplasty: histopathologic and bone morphometric findings

Authors

Isao Matsushita¹, Yuji Morita¹, Ryuichi Gejo¹ and Tomoatsu Kimura¹

1. Department of Orthopaedic Surgery, Faculty of Medicine, University of Toyama, 2630 Sugitani, Toyama 930-0194, Japan

Received:

01 May 2007

Accepted:

07 June 2007

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Abstract

We encountered a patient who developed metallosis after total knee arthroplasty (TKA), resulting in loosening of the implant, bone resorption, reduced bone formation, and fracture. The implant was replaced with a NexGen modular revision TKA system after autologous bone and hydroxyapatite granule grafting. Histopathologic examination showed accumulation of metallic debris and tartrate-resistant acid phosphatase-positive cells around the trabecular and cortical bone. Examination of hard tissue specimens showed a reduced bone volume (determined by bone histomorphometry) and an increase of all osteoid parameters, indicating disturbance of mineralization in addition to increased bone resorption.

Key words

Bone histomorphometry - Bone resorption - Metallosis - Mineralization - Total knee arthroplasty