Objective To investigate the method and effectiveness of vacuum seal ing drainage (VSD) combined with debridement for treatment of deep infection after hip or knee replacement. Methods Between September 2006 and May 2010, 13 cases of deep infection after joint replacement surgery were treated, including 5 males and 8 females with an average ageof 62.5 years (range, 56-78 years). Infection occurred at 7 days to 1 year and 2 months (median, 14 days) after joint replacement surgery. The time from infection to admission was 8 days to 4 years and 6 months (median, 21 days). Purulent secretion with or without blood were observed in all patients; sinus formed in 5 cases; and unhealing of incision or drainage opening disunion were observed in 8 cases. The size of skin defect at secretion drainage or sinus opening site was 5 mm × 3 mm to 36 mm × 6 mm; the depth of drainage tunnel or sinus was 21-60 mm. The histopathological examination in 11 patients showed acute infection or chronic infection with acute onset in 10 cases, and tuberculosis in 1 case. In 6 cases of secretion culture, Staphylococcus aureus was isolated from 5 cases. After thorough debridement, wound irrigation was performed during the day and VSD during the night in 10 cases. VSD was merely performed in 3 cases. Results In 1 case after revision total hip arthroplasty, the wound bled profusely with VSD, then VSD stopped and associated with compression bandage, VSD proceeded again 3 days later with no heavy bleeding. All the patient were followed up 1 year to 4 years and 5 months (mean, 2 years and 11 months). Infection were controlled 7-75 days (mean, 43 days) after VSD in 10 cases. In these cases, prosthesis were reserved, no recurrent infection was observed, wound were healed, limb function were reserved. VSD was refused in 1 case because of hypersensitive of the pain at the vacuum site, infection control was failed and amputation at the thigh was proceeded. The effect was not evident in 1 case with tuberculosis infection, then the prosthesis was removed and arthrodesis was proceeded followed by complete union. In 1 case, infection was cured with VSD, recurrent infection happened after 9 months, antibiotic-impregnated cement spacer was used at end, and no recurrence was observed 1 year and 4 months later. Conclusion VSD combined with debridement can drainage deep infection sufficiently, promote wound healing, reduce recurrent infection rate, maximize the possibil ity of prosthesis preservation.
Objective To develop a kind of biological artificial knee joint prosthesis with stereo mesh surface for rabbit, to observe its function after being implanted into rabbit knee joint and to evaluate its biomechanical property.Methods Thirty adult New Zealand rabbits were randomized into experimental and control groups (n=15), total left knee arthroplasty was performed in both groups, no patella replacement was performed. Biological artificial knee joint prosthesis with stereo mesh surface was self-designed. The adjacent 4/5 surface of femur and tibia stem of the prosthesis was covered by stainlesssteel stereo mesh, the inner surface of femur condyles and tibia plateau was welded with two layers of stainless steel stereo mesh, then the prosthesis underwent biological fixation in the experimental group. Meanwhile, prosthesis having smooth marrow internal stem, femoral condyle and tibial plateau internal surface and sharing the same shape and size with the experimental group were prepared and fixed with bone cement in the control group. The postoperative general condition of animal was observed. At 1, 3 and 6 months after operation, the rabbits were killed for gross observation, X-ray examination was conducted to observe the fixation condition of prosthesis and heal ing condition, the range of motion (ROM) of knee joints was tested, biomechanics test was carried out and the maximum shear strength of prosthesis bone interface was calculated. Results In each group, there was 1 rabbit died and new one was added during the second experiment. The others survived till the end of the experiment and crawled normally 7 days after operation. For the excellent and good rate concerning the recovery of ROM of the knee joint at 1, 3 and 6 months after operation, the experimental group was 60%, 80% and 80%, respectively, and the control group was 60%, 80% and 60%, respectively, indicating there were no significant differences between two groups (P gt; 0.05). For the experimental group, the gross observation showed large quantities of bone reconstruction, X-ray films indicated the prosthesis fitted well, with sol id fixation and without dislocation and lossening；while for the control group, the gross observation showed no bone reconstruction, X-ray films displayed the location of prosthesis was good, with sol id fixation and without dislocation and loosening. Radiolucent zone around the femur prosthesis and stress shileding occured 6 months after operation. For the maximum shear strength, the experimental group was less than the control group at 1 month after operation; and it was higher than the control group at 3 and 6 months after operation, indicating there were significant differences betweentwo groups (P lt; 0.01). Conclusion The fixation strength of the biological artificial knee joint prosthesis with stereo meshsurface is better than that of the bone cement prosthesis in rabbits at 3 and 6 months after operation.