Periprosthetic infection is a serious complication after total hip arthroplasty (THA). Two stage procedure using antibiotic-impregnated cement spacer is one of the treatments for late chronic infection after THA. We investigated the effects of two stage procedure on the infection control and the recurrence of infection after revision THA. We retrospectively reviewed a consecutive series of 10 cases of a periprosthetic infection after hip arthroplasty, including 3 THA and 7 bipolar hemiarthroplasty (BHA). They were treated with two stage procedure using antibiotic-impregnated cement spacer from 2004 to 2009. There were 4 women and 6 men with an average age of 68.4 years. The pathogens were methicilin-resistant Staphylococcus aureus (MRSA) in 3 cases, coagulase-negative Staphylococcus (CNS) in 2 cases, Enterococcus in 2 cases, Streptococcus in 2 cases, and unknown in 1 case. After removal of the prosthesis, extensive debridement was performed to remove infected tissues and residual cement. After irrigation with iodine solution, antibiotic-impregnated cement spacer was inserted with proximal cement fixation to prevent dislocation and fracture of the cement spacer. The antibiotics that were impregnated in the cement spacer were VCM in 8 cases, MEPM in 1 case, and CAZ in 1 case. Intravenous antibiotics were administrated for 3 weeks after this first stage surgery, and then oral antibiotics were administrated until C-reactive protein (CRP) rates became negative. After confirming the culture of joint fluid contained no pathogens, second stage revision surgery was performed. The average follow-up period after revision THA was 2.3 years. We investigated the period from first stage surgery to the day when CRP became negative, and to the day of second stage surgery. The incidence of recurrence of infection after revision THA was investigated.Introduction
Materials and Methods
In previous congress of ISTA in Hawaii, we reported the results about accuracy of the cup center position in our image-free navigation system. In the new version of our navigation system, leg elongation and offset change as well as cup center position can be navigated. In this study, we therefore investigated the accuracy of cup center position, leg elongation and offset change. Twenty four THA operations were performed with using the image-free OrthoPilot THA3.1 dysplasia navigation system (B. Braun Aesculap, Tuttlingen, Germany) between August 2009 and December 2009 by three experienced surgeons. In this system, cup center height was shown as the distance from tear drop, and cup medialization was shown as horizontal distance from inner wall of acetabulum. Leg elongation and offset change were navigated by comparing the two reference points in femur between registration before neck resection and that after inserting the trial implant. After operation, the cup angles were measured on CT image, and cup center position, leg elongation and offset change were measured on plain radiography. We compared these values that indicated by the navigation system to those measured on the CT image and the plain radiography. The average cup inclination was 37.5 ± 7.0 degree and anteversion was 22.2 ± 4.7 degree. The average absolute difference between navigation and measured angles were 5.2 ± 4.0 degree in inclination, 5.9 ± 4.0 degree in anteversion. The difference of cup height was 5.8 ± 3.9 mm, cup medialization was 3.8 ± 2.7 mm, leg elongation was 4.3±3.3mm, and offset was 5.4±4.1mm, respectively. By using this new version navigation system, we can plan the cup center position and navigate it within smaller error of vertical and horizontal direction than the previous system. Moreover, leg elongation and offset change can be satisfactory navigated during operation. However surgeon's skill and learning curve might have influence the accuracy. We have to continue to evaluate this system and make effort to further improvement.
