ObjectiveTo investigate the mid-term effectiveness of debridement with prosthesis retention for periprosthetic joint infection (PJI) after total hip arthroplasty (THA) and total knee arthroplasty (TKA), and analyze the influence factors that affected the effectiveness.MethodsA clinical data of 45 cases with PJI after THA (16 cases) and TKA (29 cases) that were treated with debridement with prosthesis retention between January 2011 and January 2015 were collected and analyzed. There were 19 males and 26 females with a mean age of 58.4 years (range, 23-78 years). PJI occurred after primary joint arthroplasty in 40 cases and after revision in 5 cases. The mean time interval between the performance of infection symptoms and the arthroplasty or revision was 15.5 months (range, 0.5-72.0 months). The time interval between the performance of infection symptoms and debridment was 35 days (range, 3-270 days). There were early postoperative infections in 13 cases, acute hematogenous infections in 24 cases, and late chronic infections in 8 cases. X-ray films showed that the location of prosthesis was good. The results of bacilli culture showed that 28 cases were positive and 17 were negative. Twelve cases had sinuses. Length of stay, Hospital for Special Surgery (HSS) score, and Harris score were recorded to evaluate risk factors by using a multivariate logistic regression.ResultsThe mean length of stay was 22.6 days (range, 5-79 days). All patients were followed up 24-74 months (mean, 52 months). There were 33 cases that retained the prosthesis without further evidence of infection with the success rate was 73.3%. There were significant differences in Harris score and HSS score between pre- and post-operation (P<0.05). The univariate analysis results showed that the failure of debridement with prosthesis retention had a significant correlation with sinus developing and duration of infection symptoms more than 14 days (P<0.05). Multivariate logistic regression analysis results showed that sinus developing was an independent risk factor of failure (P<0.05).ConclusionDebridement with prosthesis retention plays an important role in treating PJI after THA and TKA. These patients with sinus performing and duration of infection symptoms more than 14 days have higher risk to develop infection again.
Objective To study the imaging features of the hip joint by measuring the imaging parameters of spine, pelvis, and hip joint before and after total hip arthroplasty (THA) in patients with ankylosing spondylitis (AS) undergoing THA so as to provide reference for selection of operation methods and prosthesis. Methods Between January and July 2015, 38 patients (56 hips) with AS underwent primary THA as AS group, and 36 patients (45 hips) with osteonecrosis of the femoral head underwent THA as control group. There was no significant difference in side (χ2=1.14,P=0.95). The acetabular abduction angle (ABA), acetabular anteversion angle (AVA), center collum diaphyseal (CCD), offset, height from rotation center to lesser trochanter (HRCLT), femoral intertrochanteric distance (FID) were measured by CT three-dimensional morphology. The canal flare index (CFI), cortical thickness index (CTI), pelvic incidence (PI), sacral slope (SS), and pelvic tilt (PT) were measured by X-ray film before operation. The AVA, ABA, and the filling ratio were measured on the postoperative X-ray film. Results There was no significant difference in preoperative AVA and ABA and postoperative ABA between 2 groups (P>0.05), but significant difference was found in postoperative AVA (t=6.71,P=0.00). The mean PI, SS, and PT in AS group were 48.37° (range, 41-58°), 5.64°(range, 2-11°), and 12.85° (range, 5-26°), respectively. There was significant difference in CCD, CFI, and CTI between 2 groups (t=3.63,P=0.04;t=5.12,P=0.02;t=3.91,P=0.04), but offset, HRCLT, and FID all showed no significant difference (t=0.41,P=0.36;t=0.33,P=0.56;t=0.59,P=0.12). On the basis of the Noble classification, medullary cavity of the femur was rated as chimney type, ordinary type, and champagne flute type in 32, 18, and 6 hips of AS group, and in 4, 28, and 13 hips of control group respectively. Filling ratio of distal segment in AS group was significantly lower than that in control group (t=5.64,P=0.02), but there was no significant difference in the filling ratio of middle and proximal segments between 2 groups (t=0.29,P=0.61;t=0.55,P=0.13). Conclusion Compared with patients having osteonecrosis of the femeral head, there is no significant difference in preoperative AVA and ABA, but postoperative AVA significantly increase in patients with AS. Because AS patients have mainly chimney type medullary cavity of the femur, the filling ratio of middle and distal segment is lower when tapered stems are used, and the filling ratio of anatomic stems is higher.