Aims

We report the natural course of Baker’s cysts following total knee arthroplasty (TKA) at short- and mid-term follow-up.

We conducted a meta-analysis, including randomised controlled trials (RCTs) and cohort studies, to examine the effect of patient-specific instruments (PSI) on radiological outcomes after total knee replacement (TKR) including: mechanical axis alignment and malalignment of the femoral and tibial components in the coronal, sagittal and axial planes, at a threshold of > 3º from neutral. Relative risks (RR) for malalignment were determined for all studies and for RCTs and cohort studies separately.

Of 325 studies initially identified, 16 met the eligibility criteria, including eight RCTs and eight cohort studies. There was no significant difference in the likelihood of mechanical axis malalignment with PSI versus conventional TKR across all studies (RR = 0.84, p = 0.304), in the RCTs (RR = 1.14, p = 0.445) or in the cohort studies (RR = 0.70, p = 0.289). The results for the alignment of the tibial component were significantly worse using PSI TKR than conventional TKR in the coronal and sagittal planes (RR = 1.75, p = 0.028; and RR = 1.34, p = 0.019, respectively, on pooled analysis). PSI TKR showed a significant advantage over conventional TKR for alignment of the femoral component in the coronal plane (RR = 0.65, p = 0.028 on pooled analysis), but not in the sagittal plane (RR = 1.12, p = 0.437). Axial alignment of the tibial (p = 0.460) and femoral components (p = 0.127) was not significantly different.

We conclude that PSI does not improve the accuracy of alignment of the components in TKR compared with conventional instrumentation.

Cite this article: Bone Joint J 2014; 96-B:1052–61.

Background

Thromboembolic disease is a common complication of total hip replacement (THR). The administration of postoperative anticoagulants is therefore highly recommended. The purpose of this study was to compare rivaroxaban with fondaparinux with regards to their safety and effectiveness for the prevention of venous thromboembolic events (VTE) after THR.

Purpose of the study: Conventional techniques for implantation of a TKA allow a neutral mechanical axis (HKA 180±3) in 70 to 86% of patients. The purpose of this work was to evaluate the contribution of intraoperative radiologic assistance for this objective.

Material and methods: We conducted a prospective randomised study in a single-operator consecutive series of cemented TKA, model TC-SB, excluding revisions and frontal deviations > 25. The series included 65 women and 39 men, mean age 73 years. All operations were performed on a radiolucent table. An extramedullary guide was used for the tibial cut and an intramedullary guide for the femoral cup. Patient randomisation was done after the cuts. According to the randomisation, the orientation of the cuts in the frontal plane was measured radiographically using a fluoroscope and an aiming plate situated on the hip, then the ankle. Secondary cuts were made if the angular deviation was greater than 1°. The position of the TKA assisted by the fluoroscope (group R+, n=52) and that of the non-assisted TKA (group R-, n=52) was assessed on the digitalised goniometry.

Results: Mean operative time was 70 minutes in group R+ and 59 minutes in group R-. In group R+, the mean mechanical alignment was 3.9 varus preoperatively and 0.13 valgus postoperatively (5 valgus to 3 varus) with 91% in the ±3 range. In group R-, the mean mechanical alignment was 6.7 varus preoperatively and 0.06 varus postoperatively (6 varus to 5 valgus) with 80% of the cases in the ±3 range. The standard deviation was 2 in group R+ and 2.7 in group R-, with no significant difference.

Discussion: The accuracy of the implantation obtained with the conventional instrumentation for the TC-SB prosthesis is among the best reported in the literature. Intraoperative radiological assistance enabled a tighter spread of the results around the mechanical alignment. The technique was simple to use and precise. The mean duration of exposure to the fluoroscope was 3 s (PDS 3 – 35 gray cm²).

Conclusion: We reserve this assistance in priority for patients with major bone deformities or medullary obstacles.

Purpose of the study: The risk of homologous blood transfusion for primary total knee arthroplasty (TKA) varies between centres from 4 to 72%. Measurement of mean blood loss for patients undergoing primary total hip or knee arthroplasty led us to adopt a global blood-sparing protocol.

Material and methods: This was a prospective observational study involving 90 TKA (TC-SB) implanted by one surgeon in 56 women and 33 men, mean age 74 years, ASA 3 for 29%, mean BMI=31. Programmed autologous transfusion and blood recovery were not applied. Alpha epoeitine (EPO was administered in the preoperative period in accordance with the predicted serum haemoglobin at discharge. Tranexamic acid (TA) was injected intravenously during the operation.

Results: The mean operative time was 63 minutes, mean tourniquet time 51 minutes. During the perioperatively period, the mean 7-day blood loss was 566±254 ml red cells and 1560±643 total blood. Mean serum haemoglobin at discharge was 1.0 g/dl. Fourteen percent of patients had a postoperative serum haemoglobin less than 10 g/dl (lowest level 8.4 g/dl). One patient had a transfusion; this was a man in his nineties who was operated on without a tourniquet and without TA because of a poor arterial system. Nearly 86% of patients received TA with a significant (p< 0.05) decrease in bleeding compared with those who did not receive TA (365 ml total blood). EPO was delivered for 22% of patients (2.8 injections on average) to reached 14.2 g/dl the day before the operation.

Discussion: This overall strategy for blood sparing enabled us to reduce the risk of transfusion and limit costs. In this series, the prescription of EPO was not targeted to reach a set level preoperatively but was based on the predicted serum haemoglobin level at discharge. Thus seven patients with a preoperative haematocrit below 39 did not receive EPO. None of these patients were transfused. Their discharge haemoglobin was between 10.7 and 12.4g/dl. Use of TA should be included in the calculation of the predicted discharge haemoglobin level in order to better determine candidates for EPO injections.

Introduction: A prospective analysis of the total blood losses (TBL) and the rate of blood transfusions was conducted for the unilateral primary TKA performed at our clinic from January 2008 to March 2009. A transfusion-sparing strategy was used, based on the use of the tourniquet, the intraoperative injection of tranexamic acid and the preoperative administration of erythropoietin for patients with hemoglobin baseline level less than 13 gr/dl. The formula of Gross and the values of Gilcher were utilized to calculate TBL and to estimate the blood volume of the patient.

No autologous blood transfusion systems were employed. The postoperative program consisted of pain control and anticoagulants. Results were compared with a historical cohort of patients operated on with the aid of cell salvage.

Materials and Methods: One hundred – five patients (mean age, 73 years) were admitted to the study group and compared to an historic group including 44 patients (mean age, 70 years).

No significant differences were found between the study arms regarding BMI (31 kg/m2), ASA score and operating time (65 minutes).

Results: Mean TBL was 1560 ml versus 1821 ml in the historic group throughout the entire 8-day period. In the study group, TBL was significantly reduced in the patients who received tranexamic acid. In both groups, one patient received homologous blood transfusion. In the historic group, 41 of the 44 patients received autologous blood transfusion from reinfusion drains (mean volume 314 ml). Finally, the mean Hb at postoperative day 8 (POD 8) was 10,95 g/dl in the study group versus 10,35 gr/dl in the historic group (p< 0.01). Costs were superior in the study group in relation to the use of erythropoietin. No complications were related to the use of the blood –sparing pharmacologic agents.

Discussion: This study confirms that recent improvements in surgical and anesthetic procedure allow for performing routine unilateral TKA with a marginal rate of blood transfusion when the procedure is achieved by an experienced team using a blood-conserving strategy. The strengths of this study include the calculation of blood loss and the homogeneity between the study arms. However the reduction of TBL related to the use of tranexamic acid was not evaluated within the setting of a randomized clinical trial. Furthermore, the results were obtained in patients having a high BMI.

Conclusion: The blood transfusion sparing plan improved quality of care by reducing the risks of transfusion and maintaining a satisfactory Hb level at POD 8

Survival analysis is an important tool for assessing the outcome of total joint replacement. The Kaplan-Meier method is used to estimate the incidence of revision of a prosthesis over time, but does not account appropriately for competing events which preclude revision. In the presence of competing death, this method will lead to statistical bias and the curve will lose its interpretability. A valid comparison of survival results between studies using the method is impossible without accounting for different rates of competing events. An alternative and easily applicable approach, the cumulative incidence of competing risk, is proposed. Using three simulated data sets and realistic data from a cohort of 406 consecutive cementless total hip prostheses, followed up for a minimum of ten years, both approaches were compared and the magnitude of potential bias was highlighted. The Kaplan-Meier method overestimated the incidence of revision by almost 4% (60% relative difference) in the simulations and more than 1% (31.3% relative difference) in the realistic data set. The cumulative incidence of competing risk approach allows for appropriate accounting of competing risk and, as such, offers an improved ability to compare survival results across studies.