Venous thromboembolism (VTE) is a serious complication after total hip and knee arthroplasty. There is still no consensus regarding the best mode of thromboprophylaxis after lower limb arthroplasty. The aim of this study was to ascertain the efficacy, safety profile and rate of adverse thromboembolic events of aspirin as extended out of hospital pharmacological anticoagulation for elective primary total hip and knee arthroplasty patients and whether these rates were comparable with published data for low molecular weight heparin (LMWH). Data was extracted from a prospective hospital acquired thromboembolism (HAT) database. The period of study was from 1st Jan 2013-31st Dec 2016 and a total of 6078 patients were treated with aspirin as extended thromboprophylaxis after primary total hip and knee arthroplasty. The primary outcome measure of deep vein thrombosis and pulmonary embolism within 90 days postoperatively was 1.11%. The secondary outcome rates of wound infection, bleeding complications, readmission rate and mortality were comparable to published results after LMWH use. The results of this study clearly show that Aspirin, as part of a multimodal thromboprophylactic regime, is an effective and safe regime in preventing VTE with respect to risk of DVT or PE when compared to LMWH. It is a cheaper alternative to LMWH and has associated potential cost savings.
Our aim was to compare the biomechanical strength modified side-to-side repair with modified pulvertaft technique keeping overlap length, anchor points, type of suture, suture throw and amount of suture similar. In our study, we have used turkey tendons. Two investigators performed 34 repairs during one summer month. All mechanical testing was carried out using the tensile load testing machine. Variables measured were maximum load, load to first failure, modulus, load at break, mode of failure, site of failure, tensile strain, and tensile stress. The statistical comparison was carried by Levene's test and T test for means. The mean maximum load tolerated by modified side-to-side repair was 50.3N(S.D13.7) and that by modified pulvertaft 46.96N(S.D: 16.4), overall it was 48.29 N (S.D: 14.57). The tensile stress at maximum load for modified pulvertaft and modified side-to-side repair was 4.2MPa(S.D: 3.1) and 4.7 MPa (S.D: 3.8) respectively {Overall 4.3MPa(S.D: 3.5)}. The tensile stress at yield was 4.01 MPa (S.D: 3.1) and 5.5 MPa (S.D: 3.7) respectively for modified pulvertaft and modified side-to-side repair {overall 4.44 MPa (S.D: 3.45)}. The tensile strain at maximum load respectively for side-to-side and modified pulvertaft repair was 7.87%(S.D: 33.3) and 7.84%(S.D: 34.02) respectively. We found no statistical difference between 2 repairs in terms of strength, load to first failure, and maximum load to failure. The suture cut through was the commonest mode of failure. Our study uniquely compares two techniques under standard conditions, and contrary to existing evidence found no difference.
Creating cement keyholes (i.e. drilling simple holes in cancellous bone to allow cement filling) is a practice used in multiple scenarios in orthopaedic surgery to ensure improved fixation between the bone-cement interface and as such between bone and prosthesis. It is most commonly used in hip arthroplasty to secure fixation of the cup to the acetabulum by drilling keyholes in acetabulum. However very little research has been conducted into what the dimensions of such cement keyholes should be. The following laboratory based research was performed to provide insight into the optimum dimensions of cement keyholes. The investigator designed a novel arrangement to enable testing of keyholes. Beechwood block models were then made to this design testing keyholes of varying diameters and depths. These were cemented with acrylic bone cement and then loaded to failure. A finite system analysis was also performed. Results show that stresses are concentrated at the base of the keyhole. As such increasing diameter of keyhole infers greater strength, but there is no relationship between depth and strength. This has been further confirmed with finite element analysis. We suggest the width of cement keyholes bears more importance than the depth and propose drilling wide but shallow keyholes.
