Total Hip Arthroplasty Using Large-Diameter Metal-On-Metal Articulation in Patients With Neuromuscular Weakness

The purpose of this prospective study was to evaluate the clinical and functional outcomes of THA using large-diameter metal-on-metal articulation in patients with neuromuscular weakness. Nineteen consecutive patients (19 hips) with neuromuscular weakness and displaced femoral neck fractures were enrolled. Functional improvement and recovery, radiological evaluation of THA and surgical morbidity were assessed. Mean Harris hip and WOMAC scores at final follow-up were 81.0 and 42.9, respectively. At final follow-up, no dislocation, metal hypersensitivity, or osteolysis was observed and no patient required revision of THA. The findings of this study indicate that the functional results of THA using large-diameter metal-on-metal articulation in patients with neuromuscular weakness can produce satisfactory outcomes with early functional recovery and a low dislocation rate.     

Plain Radiographs Fail to Reflect Femoral Offset in Total Hip Arthroplasty

Successful biomechanical reconstruction is a major goal in total hip arthroplasty (THA). We measured leg length (LL), global (GO) and femoral offset (FO) change on anteroposterior pelvis radiographs and on three-dimensional computed-tomography (3D-CT) with fiducial landmarks after cementless THA on 18 hips of cadaveric specimens. Measurements on radiographs were performed twice by four examiners and showed high interobserver (mean CCC ≥ 0.79) and intraobserver agreements (mean ICC ≥ 0.88). Mean differences between radiographic and 3D-CT measurements were 1.0 (SD 2.0) mm for LL, 0.6 (SD 3.6) mm for GO and 1.4 (SD 5.2) mm for FO. 1% of radiographic LL-, 15% of GO- and 35% of FO measurements were outside a tolerance limit of 5 mm. Radiographs seem acceptable for measuring LL/GO change but fail to reflect FO change in THA.     

Can Total Knee Arthroplasty Be Safely Performed Among Nonagenarians? An Evaluation of Morbidity and Mortality Within a Total Joint Replacement Registry

As the nonagenarian patient population continues to grow, more patients aged 90 and over will become candidates for total knee arthroplasty (TKA). This study evaluated the patient characteristics and incidence of postoperative morbidity and mortality of 216 nonagenarian TKA patients among 81,835 primary TKA patients followed by a total joint replacement registry. Nonagenarians had a greater number of comorbidities preoperatively, experienced a higher rate of deep vein thrombosis and 30 day mortality, and had a longer hospital length of stay. However, nonagenarians did not have an increased risk of infection nor pulmonary embolism and postoperative mortality was within expected rates for individuals 90 years and older. Higher readmission rates, however, highlight the benefits of close follow up during a prolonged postoperative period.     

Comparison of Intravenous versus Topical Tranexamic Acid in Total Knee Arthroplasty: A Prospective Randomized Study

The purpose of this study was to compare the efficacy of topical Tranexamic Acid (TXA) versus Intravenous (IV) Tranexamic Acid for reduction of blood loss following primary total knee arthroplasty (TKA). This prospective randomized study involved 89 patients comparing topical administration of 2.0 g TXA, versus IV administration of 10 mg/kg. There were no differences between the two groups with regard to patient demographics or perioperative function. The primary outcome measure, perioperative change in hemoglobin level, showed a decrease of 3.06 ± 1.02 in the IV group and 3.42 ± 1.07 in the topical group (P = 0.108). There were no statistical differences between the groups in preoperative hemoglobin level, lowest postoperative hemoglobin level, or total drain output. One patient in the topical group required blood transfusion (P = 0.342). Based on our study, topical Tranexamic Acid has similar efficacy to IV Tranexamic Acid for TKA patients.     

Outcomes of Total Hip Arthroplasty in Spastic Patients

Patients with spasticity and hip arthritis can present challenges to treatment. This investigation evaluated the effectiveness and safety of THA in patients with upper motor neuron disease. Twenty-seven consecutive patients with history of cerebral palsy (CP) or acquired spasticity (AS) underwent 30 THAs for treatment of hip arthritis. They were followed for an average 2.5 years (range 2.1–12.1). Patients with CP were more likely to require hip adductor release and hip flexor lengthening at the time of THA. Statistically significant improvements were made in Harris Hip Scores, pain scores, range of motion, ambulatory status, and the use ambulatory-assistive devices. There were no dislocations in this group. Patients with spasticity can benefit from THA in terms of pain relief and improved mobility with relatively low complications.     

Evaluation of the 3-Dimensional,Weight-Bearing Orientation of the Normal Adult Knee

The purpose of this study was to use 3-dimensional, weight-bearing images corrected for rotation to establish normative data of limb alignment and joint line orientation in asymptomatic, adult knees. One hundred adults (200 lower extremities) were recruited to receive weight-bearing, simultaneous biplanar imaging of both lower extremities. Multiple radiographic parameters were measured from 3D images, corrected for limb rotation. 70.0% of knees were in neutral, 19.5% in varus, and 10.5% in valgus overall alignment. Only 31 % of knees possessed both a neutral mechanical axis and the absence of joint line obliquity. There was substantial agreement between the 2D and 3D images for overall mechanical alignment (κ = 0.77), but only a moderate agreement for joint line obliquity (κ = 0.58). A substantial portion of asymptomatic adults possess either a varus or valgus mechanical alignment and joint line obliquity.     

A Nomogram to Predict Major Complications After Hip and Knee Arthroplasty

We aimed to develop a nomogram for risk stratification of major postoperative complications in hip and knee arthroplasty based on preoperative and intraoperative variables, and assessed whether this tool would have better predictive performance compared to the Surgical Apgar Score (SAS). Logistic regression analysis was performed to develop a nomogram. Discrimination and calibration were assessed. Net reclassification improvement (NRI) was used to compare to the SAS. All variables were found to be statistically significant predictors of post-operative complications except race and lowest heart rate. The concordance index was 0.76 with good calibration. Compared to the SAS, the NRI was 71.5% overall. We developed a clinical prediction tool, the Morbidity and Mortality Acute Predictor for arthroplasty (arthro-MAP) that might be useful for postoperative risk stratification.     

Gap Balancing Sacrifices Joint-Line Maintenance to Improve Gap Symmetry: A Randomized Controlled Trial Comparing Gap Balancing and Measured Resection

A total knee arthroplasty can be completed using two techniques; measured resection or gap balancing. A prospective blinded randomized controlled trial was completed with 103 patients randomized to measured resection (n=52) or gap balancing (n=51). Primary outcome measure was femoral component rotation. Secondary outcome measures were joint-line change, gap symmetry and function and quality-of-life outcomes. Gap balancing resulted in a significantly raised joint-line compared to measured resection. Gap symmetry was significantly better using gap balancing. Functional outcomes and quality-of-life were not significantly different at 24 months. Using computer navigation, gap balancing significantly raises the joint-line in order to improve gap symmetry. This does not result in a clinical difference in function or quality of life at 24 months.     

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.