A Trabecular Metal Modular Acetabular System (Zimmer, Warsaw, Indiana, USA) is a peripheral rim expansion (elliptical) cup, i.e. a non-hemispherical cup. Radiologically a non-hemispherical cup may be deferent from other conventional hemispherical cups. We reviewed radiological findings of a Trabecular Metal Modular Acetabular System chronologically. Twenty six patients with osteoarthritis underwent primary total hip arthroplasty (THA) using a Trabecular Metal Modular Acetabular System from 2011 to April 2013. Twenty five patients (follow-up rate: 96.2%) 31 hips could be followed-up over a year were registered. In common, the diameter of every femoral head was 32 mm. We planned the acetabular cup inclination angle to be 45-degree, the cup coverage with host-bone (cup-CE angle) to be over 10-degree, and high hip center was allowed up to 20mm. In case of the cup-CE angle under 10-degree, an acetabular cup was placed medially using Dorr's medial protrusio technique. We established the medial protrusion angle indicating the degree of medial protrusion of an acetabular cup over the pelvic internal wall. The medial protrusion angle was defined by the center point of THA (C) and the 2 cross-points (X1, X2) which the outline of an acetabular cup crosses the Kohler's line (Figure 1). The cup anteversion angle was measured by the method of Lewinnek, and the cup fixation was evaluated according to the Tompkin's classification.Purpose
Methods
Total knee arthroplasty (TKA) has been proven to be the most effective treatment for patients with severe or “end-stage” joint disease. Although infection is not a frequent complication of total knee arthroplasty, it is certainly one of the most dreaded. The purpose of this study was to identify related factors associated with septic arthritis. 2202 primary total knee arthroplasties were done in 1257 patients between 1995 and 2006. Of these knee arthroplasties, 2022 knees in 1146 patients were available for follow-up. Revision arthroplasty procedures and infected knees were excluded. 252 knees in 147 males, 1770 knees in 999 females were done. Their mean age at the time of primary TKA was 70.6 (range, 26–91) years. The mean follow-up period post primary TKA was 48 (range, 3–145) months. The medical records were reviewed to extract the following information: age, gender, body mass index, preoperative CRP, preoperative ESR, preoperative TP, duration of surgery, operative blood loss, total blood loss, duration of surgical drain, duration of antibiotic prophylaxis, primary diagnoses, smoking, diabetes mellitus, steroid or DMARDs therapy, previous operation around the knee joint, previous arthroscopic surgery, previous except arthroscopic surgery, previous operation of high tibial osteotomy (HTO) or open reduction internal fixation (ORIF), residue of internal fixation material, bone graft, patella replacement, and bone cement. Proportions were compared using the chi-square or two-tailed Fisher’s exact test, as appropriate. Continuous variables were compared by the student’s t-test. Logistic regression analysis (stepwise) of selected variables from univariate analysis was performed to identify factors independently associated with the development of infection following total knee arthroplasty. During the study period, 17 infected knee arthroplasties in 17 patients were identified. The infections occurred in 8 males and 9 females, with a medial age of 69.5 years. The results of univariate analysis indicating those variables statistically associated with infection are : gender (p <
0.0001), smoking (p = 0.02), previous operation around the knee joint (p = 0.001), previous except arthroscopic surgery(p <
0.0001), previous operation of ORIF (p <
0.0001), residue of internal fixation material (p <
0.0001). Logistic regression analysis indicated that the four predictors of infection following total knee arthroplasty were gender (odds ratio [OR], 0.2; 95% confidence interval [CI95], 0.1 to 0.6; P=0.005), previous operation of ORIF (OR, 7.9; CI95, 1.1 to 57.1; P=0.041), residue of internal fixation material (OR, 26.0; CI95, 4.5 to 151.0; P<
0.001), body mass index (OR, 1.2; CI95, 1.0 to 1.3; P=0.007). We conclude that the risk factors of infection after TKA were previous operation of ORIF, gender, residue of internal fixation, and body mass index.
