Relationship Between Mechanical Axis-Derived and Anatomic Landmark-Derived Femoral Rotation in TKA: A Three-Dimensional CT Study

We sought to determine the relationship between the mechanical axis-derived and the anatomic landmark-derived femoral rotational axes using three dimensional computed tomographic images of 20 lower extremities. The mechanical axis-derived femoral rotational axis was created on the distal articular surface of the femur using coronal mechanical limb axis and the reconstructed images of the femur. Then, we measured the angular difference between mechanical axis-derived and anatomic landmark-derived femoral rotational axes. The mechanical axis-derived femoral rotational axis was externally rotated with a mean of 2.2° (range, 0 to 4.7°; SD, 1.0) compared with the surgical epicondylar axis. Our findings should be considered to obtain a proper femoral rotational axis in total knee arthroplasty.     

Zirconia Phase Transformation,Metal Transfer,and Surface Roughness in Retrieved Ceramic Composite Femoral Heads in Total Hip Arthroplasty

Ceramic femoral heads have had promising results as a bearing surface in total hip arthroplasty. Our objective was to evaluate a series of retrieved alumina-zirconia composite ceramic femoral heads for evidence of the tetragonal to monoclinic zirconia phase transformation, metal transfer and articular surface roughness. Raman spectra showed evidence of the zirconia phase transformation in all retrieved specimens, with distinct monoclinic peaks at 183, 335, 383, and 479 cm^− 1. All components displayed metal transfer. An increase in the zirconia phase transformation was seen with increasing time in vivo. No correlation between extent of zirconia phase transformation and the surface roughness was found. These short-term results suggest that the use of an alumina-zirconia composite ceramic is a viable option for femoral heads in THA.     

The Effect of Chronic Kidney Disease on Total Hip Arthroplasty

Patients with chronic kidney disease (CKD) undergoing total hip arthroplasty (THA) were evaluated for risk of revision, surgical site infection (SSI), thromboembolic events, mortality and readmission. 20,720 primary TKA cases were included (smaller sample for readmission evaluation, N = 9322). The prevalence of CKD among THA patients was 6.1% (N = 1269). After adjustment for age, gender, race, general health, and diabetes, CKD patients were at 1.4 (95% confidence interval 1.1–1.8) increased risk of readmission within 90 days. The adjusted risks for revision (overall, aseptic, and septic), SSI (deep and superficial), deep vein thrombosis, pulmonary embolism, and mortality (30-day, 90-day, ever) were not significantly different between patients with CKD and those without CKD. However, increased risk for 90-day readmission underscores that CKD patients are a fundamentally different population of patients.     

Are There Identifiable Risk Factors and Causes Associated with Unplanned Readmissions Following Total Knee Arthroplasty?

We conducted a retrospective review of 3218 primary total knee arthroplasties (TKA) performed over two years at an urban academic hospital network using clinical and administrative data. Increased length of stay (LOS) was associated with readmission (P < 0.001). Readmission was not associated with age (P = 0.100), gender (P = 0.608), body mass index (P = 0.329), or staged bilateral procedures (P = 0.420). The most common readmitting diagnoses were post-operative infection (22.5%), hematoma (10.1%), pulmonary embolus (7.9%) and deep vein thrombosis (5.6%). Of readmissions, 53.9% were for surgical reasons and 46.1% were for medical reasons. Certain interventions described in previous literature may be more successful in minimizing unplanned readmissions by focusing on patients with extended LOS, elevated infection risk and low socioeconomic status.     

Utility of Noninvasive Transcutaneous Measurement of Postoperative Hemoglobin in Total Joint Arthroplasty Patients

This study prospectively evaluated the clinical utility of a noninvasive transcutaneous device for postoperative hemoglobin measurement in 100 total hip and knee arthroplasty patients. A protocol to measure hemoglobin noninvasively, prior to venipuncture, successfully avoided venipuncture in 73% of patients. In the remaining 27 patients, there were a total of 48 venipunctures performed during the postoperative hospitalization period due to reasons including transcutaneous hemoglobin measurement less than or equal to 9 g/dL (19), inability to obtain a transcutaneous hemoglobin measurement (8), clinical signs of anemia (3), and noncompliance with the study protocol (18). Such screening protocols may provide a convenient and cost-effective alternative to routine venipuncture for identifying patients at risk for blood transfusion after elective joint arthroplasty.     

Predictive Risk Factors for 30-day Readmissions Following Primary Total Joint Arthroplasty and Modification of Patient Management

The Centers for Medicare and Medicaid have begun to publically publish statistics on readmissions following primary total hip (THA) and total knee arthroplasty (TKA). Our study retrospectively assesses 30-day readmissions rates following THA and TKA, performed by a single surgeon at a tertiary care medical center between 2007 and 2012. Results of a univariate analysis and logistic regression model indicated female gender, high ASA class, and increased operative time to be significantly associated with higher rates of readmission (OR 4.646, OR 1.257, and OR 5.323, respectively). Readmissions most often occurred within the first week of patient discharge. Surgical complications and gastrointestinal discomfort were the most common causes for readmission. Using readmission risk we can stratify patients into tiered critical care pathways to reduce readmissions.     

Combination of Intravenous and Topical Application of Tranexamic Acid in Primary Total Knee Arthroplasty: A Prospective Randomized Controlled Trial

This study was aimed to determine the efficacy and safety of combined intravenous (IV) and topical application of tranexamic acid (TXA) in unilateral total knee arthroplasty (TKA) compared with the IV-TXA. One hundred eight-four patients were enrolled. Participants received either 3 g of IV-TXA or 1.5 g topical TXA combined with 1.5 g IV-TXA. The results revealed that compared with the 3 g IV-TXA, adding 1.5 g topical TXA to 1.5 g IV-TXA in unilateral TKA can have the similar effectiveness in reducing transfusion rate and total blood loss without sacrificing safety. The most important is that by adding topical TXA, patients can gain a smaller maximum decline of hemoglobin (Hb), less drainage volume, less postoperative knee pain, less knee swelling, shorter length of hospital stays and higher short-term satisfaction.     

Risk Factors for Total Hip Arthroplasty Aseptic Revision

The purpose of this study was to evaluate patient, operative, implant, surgeon, and hospital factors associated with aseptic revision after primary THA in patients registered in a large US Total Joint Replacement Registry. A total of 35,960 THAs registered from 4/2001–12/2010 were evaluated. The 8-year survival rate was 96.7% (95% CI 96.4%–97.0%). Females had a higher risk of aseptic revision than males. Hispanic and Asian patients had a lower risk of revision than white patients. Ceramic-on-ceramic, ceramic-on-conventional polyethylene, and metal-on-conventional polyethylene bearing surfaces had a higher risk of revision than metal-on-highly cross-linked polyethylene. Body mass index, health status, diabetes, diagnosis, fixation, approach, bilateral procedures, head size, surgeon fellowship training, surgeon and hospital volume were not revision risk factors.     

Intra-Articular Bupivacaine Reduces Postoperative Pain and Meperidine Use After Total Hip Arthroplasty: A Randomized,Double-Blind Study

One hundred patients receiving unilateral total hip arthroplasty (THA) were randomized to receive an intra-articular injection of 300 mg bupivacaine or normal saline after completion of surgery. Pain scores of the bupivacaine group were significantly lower than those of the control group the first 12 hours postoperatively (all, P < 0.001). A significantly lower dose of meperidine was used in the study group than in the control group the first 24 hours postoperatively (median, 25 vs. 45 mg, P < 0.001). Nineteen patients in the study group required meperidine the first day after surgery, as compared to 45 patients in the control group. We conclude that intra-articular injection of bupivacaine after THA reduces pain and meperidine use in the first 12 hours after surgery.     

Outcomes and Complications Following Total Hip Arthroplasty in the Super-Obese Patient,BMI > 50

The results of total hip arthroplasty in 42 primary total hip arthroplasties in super-obese patients (BMI ≥ 50) were reviewed. The mean body mass index for the study group was 53.2 kg/m² (range 50–64). The mean preoperative Harris hip score improved from 35 to 74.8 postoperatively (P < 0.001). Twenty-four of the THAs had at least one complication. At least one major complication occurred in 11 of the THAs and at least one minor complication in 14 THAs When compared to matched 2:1 control group the super-obese patient had a significantly increased risk to experience a complication (HR 5.6 , CI = 2.8–11.0). Caution should be used when proceeding with primary total hip arthroplasty with a BMI greater than 50.