Inhibitory effect of cephalothin on matrix metalloproteinase activity around loose hip prostheses.

The inhibitory effects of drugs on matrix metalloproteinase (MMP) activity in tissues around sites of loose total hip arthroplasty (THA) prostheses were studied. For activity measurements, a DNP-S (dinitrophenyl-Pro-Gln-Gly-Ile-Ala-Gly-Gln-D-Arg) peptide degradation assay was performed by means of high-performance liquid chromatography. Neutral salt tissue extracts revealed significantly elevated MMP activity in THA samples compared with that in noninflamed synovial tissue from the knee joint. This elevation was markedly inhibited by cephalothin, but not by doxycycline, tetracycline, or gentamicin. These results indicate that cephalothin can inhibit MMP activity in reactive periprosthetic tissue and thus reduce, by a nonantimicrobial mechanism, the tissue destruction associated with the loosening of THA implants.