Expression of Cathepsin K by wear debris histiocytes in patients with total joint prostheses.

Abstract

Abstract:

Aim: To determine whether Cathepsin K, a cysteine protease and key in bone remodeling, is upregulated in wear debris histiocytes found in association with prosthetic joints and in lymph nodes draining those joints as compared to histiocytes found in a variety of other disorders of bone, joints, and lymph nodes.

Materials and Methods: Histopathologic samples from 12 patients with wear debris associated pathologies and 13 control samples were examined for Cathepsin K expression. Leica Bond immunostainer with an antibody from Cell Marque was used in immunohistochemistry staining. Immunohistochemistry Cathepsin K H-scores were divided into three categories: negative, focally positive and nonfocally positive (homogenously diffuse).

Results: Histiocytes from wear debris pathologies were all homogenously diffuse, while control samples were negative. Known-group hypothesis testing was calculated using the Mann-Whitney U test. There was a significant difference in H-scores between known groups, with a p-value of 0.000011.

Conclusion: We demonstrated of the overexpression of Cathepsin K by wear debris histiocytes in comparison to histiocytes found in other bone, joint, and lymph node pathologies. The significance of the finding in the pathogenesis of prosthetic joint failure is discussed.