Innovative antimicrobial coating of titanium implants with iodine.
BACKGROUND
Postoperative infection associated with implants remains a serious complication in orthopedic surgery. Several biomaterial surface treatments have been proposed as a means of reducing the incidence of implant-associated infections. In this study, a clinical trial was performed using an iodine-supported titanium that suppresses the microbial activities.


METHODS
A total of 222 patients with postoperative infection or compromised status were treated using iodine-supported titanium implants. The mean age of the patients was 49.4 years (range 5-85 years). One hundred twenty-seven patients were male and 95 were female. In 158 patients, iodine-supported implants were used to prevent infection, such as compromised hosts and conditions, and in 64 patients to treat active infection. White blood cell (WBCs) and C-reactive protein (CRP) levels were measured pre- and postoperatively in all patients. To confirm whether iodine from the implant affected physiological functions, thyroid hormone levels in the blood were examined. Both examinations were conducted sequentially for a year. Radiological evaluations were performed regularly after the operation. The chronological changes of the iodine amount were evaluated using half pins removed after completion of external fixation.


RESULTS
The mean follow-up period was 18.4 months (range 3-44 months). Acute infection developed in three tumor cases among the 158 patients on preventive therapy. All three recovered without removal of the implants. Infection was cured in all 64 patients with infection. Median WBC levels were in the normal range, and median CRP levels returned to <0.5 within 4 weeks after surgery. Abnormalities of thyroid gland function were not detected. None of the patients experienced loosening of the implants. There were two patients with mechanical implant failure, which was treated by re-implantation. Excellent bone ingrowth and ongrowth were found around all hip and tumor prostheses. One year later, the amount of iodine on external fixation pins remained about 20-30%.


CONCLUSIONS
Iodine-supported titanium implants can be very effective for preventing and treating infections after orthopedic surgery. Cytotoxicity and adverse effects were not detected.
Department of Orthopaedic Surgery, Graduate School of Medical Science, Kanazawa University, Kanazawa, Japan. tsuchi@med.kanazawa-u.ac.jp
Hiroyuki
H
Tsuchiya
Toshiharu
T
Shirai
Hideji
H
Nishida
Hideki
H
Murakami
Tamon
T
Kabata
Norio
N
Yamamoto
Koji
K
Watanabe
Junsuke
J
Nakase
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000891:Anti-Infective Agents, Local / Q000008:administration & dosage*; D002648:Child; D002675:Child, Preschool; D020099:Coated Materials, Biocompatible; D005260:Female; D006801:Humans; D007455:Iodine / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D016459:Prosthesis-Related Infections / Q000517:prevention & control*; D014025:Titanium; D055815:Young Adult
D000891:Anti-Infective Agents, Local; D020099:Coated Materials, Biocompatible; D007455:Iodine; D014025:Titanium