Despite proven advantages, pulsatile lavage seems to be used infrequently during preparation in cemented total knee arthroplasty. This remains irritating, as the technique has been suggested to improve radiological survival in cemented TKA, where aseptic loosening of the tibial component represents the main reason for revision. Furthermore, there may be a potential improvement of fixation strength for the tibial tray achieved by increased cement penetration. In this study, the influence of pulsed lavage on mechanical stability of the tibial component and bone cement penetration was analyzed in a cadaveric setting. Six pairs of cadaveric, proximal tibia specimen underwent computed tomography (CT) for assessment of bone mineral density (BMD) and exclusion of osseous lesions. Following surgical preparation, in one side of a pair, the tibial surface was irrigated using 1800ml normal saline and pulsatile lavage, while in the other side syringe lavage using the identical amount of fluid was applied. After careful drying, bone cement was hand-pressurized on the bone surface, tibial components were inserted and impacted in an identical way. After curing of cement, specimen underwent a postimplantation CT analysis). Cement distrubution was then assessed using a three-dimenionsional visualization software. Trabecular bone, cement and implant were segmented based on an automatic thresholding algorithm, which had been validated in a previous study. This allowed to determine median cement penetration for the entire cemented area. Furthermore, fixation strength of the tibial trays was determined by a vertical pull-out test using a servohydraulic material testing machine. Testing was performed under displacement control at a rate of 0,5mm/sec until implant failure. Data was described by median and range. Results were compared by a Wilcoxon matched pairs signed rank test with a type 1 error probability of 5 %. Median pull-out forces in the pulsed lavage group were 1275N (range 864–1391) and 568N (range 243–683) in the syringe lavage group (p=0.031). Cement penetration was likewise increased (p=0.031) in the pulsed lavage group (1.32mm; range 0.86–1.94), when compared to the syringe irrigated group (0.79mm; range 0.51–1.66). Failure occurred in the pulsatile lavage group at the implant-cement interface and in the syringe lavage group at the bone-cement interface, which indicates the weakness of the latter. Altogether, improved mechanical stability of the tibial implant and likewise increased bone cement interdigitation could be demonstrated in the current study, when pulsed lavage is implemented. Enhanced fixation strength was suggested being a key to improved survival of the implant. If this is the case, pulsatile lavage should be considered being a mandatory preparation step when cementing tibial components in TKA

Background. A number of studies have reported on the early failure of the Oxford unicompartmental knee arthroplasty. However, less evidence is available regarding the outcome following revision of failed unicompartmental knee prostheses to total knee arthroplasty. The aims of this study were to determine the time to failure for the Oxford unicompartmental knee arthroplasty and to assess the short-term outcome following revision surgery. Methods. Details of consecutive patients undergoing revision of an Oxford unicompartmental knee arthroplasty to a total knee arthroplasty at our centre between January 2000 and December 2009 were collected prospectively. Data was collected on patient demographics, indication for revision surgery, and time to revision from the index procedure. Clinical and radiological outcome following revision arthroplasty was also assessed. Results. During the study period 22 (4.5%) of 494 Oxford unicompartmental knee arthroplasties were revised to a total knee arthroplasty. Mean age at the time of revision surgery was 61.8 yr and 13 (59%) patients were male. Mean time to revision surgery from the primary procedure was 3.0 yr (range 0.6–6.2 yr). The commonest reasons for revision were aseptic loosening of the femoral (n=9) or tibial component (n=2), and undiagnosed (n=5) or patellofemoral pain (n=2). All patients were revised to a cemented total knee arthroplasty with most not requiring bone grafts. During follow-up (range 0.5–4.5 yr) no further surgery was performed in the 22 patients. In addition, there were no major postoperative complications and no evidence of radiological failure. Discussion. The present study demonstrates most failures of the Oxford unicompartmental knee arthroplasty occur within three to four years following the index procedure and are due to aseptic component loosening. These findings are consistent with other published reports regarding the early failure of this particular prosthesis. The short-term outcome following revision surgery appears to be good, however longer follow-up periods are required to determine if these good results continue

Background. There are few studies of total knee replacements with cemented tibia and uncemented femur (hybrid). Previous studies have not shown any difference in revision rate between different fixation methods, but these studies had few hybrid prostheses. This study evaluates the results of hybrid knee replacements based on data from the Norwegian Arthroplasty Register (NAR). Patients and Methods. Primary total knee replacements without patella resurfacing, reported to the NAR during the years 1999–2009, were evaluated. Hinged-, posterior stabilized- and tumor prostheses were excluded. LCS- and Profix prostheses with conforming plus bearing were included. With the risk for revision at any cause as the primary end-point, 2945 hybrid knee replacements (HKR) were evaluated against 20838 cemented knee replacements (CKR). Kaplan-Meier survival analysis and Cox regression analysis with adjustment for age, sex and preoperative diagnosis were used. Results. Kaplan-Meier estimated survival at 8 years was 94.0% (95% CI: 93.6–94.4) in the CKR group and 97.0% (95% CI: 96.0–98.0) in the HKR group. The HKR group was made op of three brands of prosthesis, LCS, LCS-complete and Profix. Profix was the only brand with a statistically significant difference between cemented and hybrid fixation. Kaplan-Meier estimated survival at 8 years was 97.7% (95% CI: 96.7–98.7) in hybrid Profix group (HPG) and 95.5% (95% CI: 94.7–96.3) in the cemented Profix group (CPG). The adjusted Cox regression analysis showed a statistically significantly lower risk for revision in the HPG group (relative risk=0.44, 95% CI: 0.39–0.59, p<0.001). Mean operating time was 15 minutes longer in the CKR group. Conclusion. Survivorship at 8 years of the hybrid primary total knee replacements was the same or superior compared to cemented total knee replacements depending on prosthesis brand Hybrid fixation seems to be a safe alternative to cemented fixation in total knee replacement surgery

Introduction. Tranexamic acid is an inhibitor of fibrinolysis that blocks the lysine-binding site of plasminogen to fibrin, and thereby decreases blood loss in patients undergoing surgery. Aims and objectives. A prospective, randomized, double-blind study was done on 100 patients undergoing primary cemented Unilateral Total Knee Arthroplasty to determine the effect of tranexamic acid on intra- and postoperative blood losses and on the transfusions requirements. Material and Methods. 100 patients undergoing unilateral cemented total knee Arthroplasty for osteoarthritis were enrolled for the study. All total knee replacement was done under combined spinal epidural anaesthesia with the use of tourniquet. 100 patients were randomized to tranexamic acid (15 mg/kg) given as a bolus intravenous injection or placebo (normal saline) given intravenously, 15 minutes before the release of tourniquiet. The blood loss (at removal of the drain 24 hours after the operation) and the number of blood transfusions required were recorded. The patients were screened for deep venous thrombosis with bilateral compression Ultrasonography using Colour Doppler imaging on the tenth postoperative day. The Hemoglobin level was measured preoperatively and on the 3rd postoperative day. The D-dimer levels were measured preoperatively and 24 hrs postoperatively. Results. Patients receiving tranexamic acid had a mean postoperative blood loss of 175 ml(range, 130–310ml) versus 330 ml (range, 210–460ml) (p value<0.05), and a total need for 3 blood transfusions versus 15. Only 3 out 50 patients in tranexamic acid group required blood transfusion whereas 12 out of 50 patients in the placebo group required transfusion. In the group receiving placebo the mean fall in hemoglobin was 2.1g/dl (range, 1.5–3.2) and in the group treated with tranexamic acid 1.3 g/dl (0.9–2) (p<0.05). At 24 hrs postoperatively, mean plasma D-dimer concentration in the Tranexamic group was half of that in the control group. No patient in either group had any evidence of deep vein thrombosis on bilateral compression Ultrasonography using Colour Doppler imaging done on the tenth postoperative day. Conclusion. Tranexamic acid 15 mg/kg given as a single bolus dose reduces blood loss, and transfusion requirements in unilateral primary cemented total kneearthroplasty without any increased risk of thrombus formation

Background. Improving quality and efficiency is a priority in health policy. Several studies have shown a correlation between high hospital volume and improved results of surgery. In Norway, orthopaedic surgeons operate a relatively low number of total knee replacements compared with other countries. The number of total knee replacements has, however, increased significantly over the past 10 years. Some studies have also shown an association between surgeon volume and outcomes after total knee arthroplasty (TKA). Purpose. We wanted to study a possible correlation between prosthesis survival and surgery volume of TKA, both with respect to hospital volume and surgeon volume. Materials and Methods. To examine the annual surgery volume per hospital we used registry data from the Norwegian Arthroplasty Register (NAR) for cemented TKA without patella component from 1994–2009. A questionnaire regarding surgeon volume in 2000 and 2009 was sent to all 58 operating hospitals in Norway, as this is not registered in the NAR. We received responses from 29 hospitals. Surgeon volume was defined by the percentage of surgeons at the hospital who operated 1–10 TKA over a year. Cox regression (without adjustment) was used to estimate proportions without revision and relative differences (RR). Analyses were also done for a subset of commonly used prostheses (AGC, LCS, LCS Complete, Duracon, NexGen, Profix), and for the prosthesis LCS and Profix separately. Results. Median annual hospital volume increased from 19 knees in 1995 to 83 in 2009. Prosthesis survival at 10 years was 92.5% (95% CI: 91.6–93.4) with 1–24 operations annually and 95.3% (93.7–96.8) with 100–149 operations. We found a lower risk of revision for hospitals with 25–49 (RR = 0.86, p = 0.06), 50–99 (RR = 0.81, p = 0.01, 100–149 (RR = 0.59, p<0.001 and 150 or more (RR = 0.48, p <.001) operations per year, compared to the hospitals with 1–24 operations. The analyses for subgroups of prosthesis brands provided similar results, except for the Profix prosthesis where there was no difference between hospital volumes. In 2000, 47% of the Norwegian hospitals had two thirds of the surgeons operating 1–10 TKA annually, but this was reduced to 24% in 2009. High annual surgeon volume gave the best results in our analyses. Conclusion. There has been an increase in the number of TKAs over time, in Norway as in other countries. Surgeon volume has also increased over time. Previously a high number of surgeons performed a low number of total knee arthroplasties, but this has been significantly reduced over the last 10 years. Survival curves from the NAR show a gradual improvement over time regarding the results of TKA. Our study indicated better results for TKA both at higher hospital volume and surgeon volume. Further analyses should investigate whether other factors may have an influence on this result

Although the use of constrained cemented arthroplasty to treat distal femoral fractures in elderly patients has some practical advantages over the use of techniques of fixation, concerns as to a high rate of loosening after implantation of these prostheses has raised doubts about their use. We evaluated the results of hinged total knee replacement in the treatment of 54 fractures in 52 patients with a mean age of 82 years (55 to 98), who were socially dependent and poorly mobile.

Within the first year after implantation 22 of the 54 patients had died, six had undergone a further operation and two required a revision of the prosthesis. The subsequent rate of further surgery and revision was low.

A constrained knee prosthesis offers a useful alternative treatment to internal fixation in selected elderly patients with these fractures, and has a high probability of surviving as long as the patient into whom it has been implanted.