Joint perception and patient perceived satisfaction after total hip and knee arthroplasty in the American population.

BACKGROUND: Total hip (THA) and knee arthroplasty (TKA) are two of the most successful procedures in orthopedics. Current evaluation trends focus on patient-reported outcomes. We sought to compare the changing WOMAC scores from various time points from pre-operative to 1-year follow-up between separate THA and TKA cohorts. In addition, we compared THA and TKA patients' joint perception, satisfaction, and function via a questionnaire. METHODS: One hundred elective THA (n = 50) and TKA (n = 50) patients at one institution were randomly selected and contacted between 2 and 4 years after the index surgery. A questionnaire assessed joint perception, satisfaction and function of their total joint. Clinical function scores utilizing the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) from the pre-operative, 3-month and 1-year post-arthroplasty visits were compared between groups. RESULTS: 78% of the THA group perceived their replaced joint as "native" vs 32% of TKA patients. 54% of THA patients (vs 16% of TKA patients) reported uninhibited function of their total joint. 24% of TKA patients noted to be least satisfied with their total joint compared to 2% in the THA group. Both groups demonstrated significant improvement in WOMAC scores after surgery, but the mean 3-month (12.4 (THA) vs 19.3 (TKA)) and 1-year (6.5 (THA) vs 14.1 (TKA)) follow-up WOMAC scores were significantly better in the THA group. CONCLUSION: Evaluation of a patient's joint perception is a valuable tool that should be used to assess function in conjunction with validated clinical functional scores. Our data suggest further improvements in total knee implant design and implantation strategies are necessary.

Polyethylene Wear in Knee Arthroplasty.

Polyethylene (PE) wear and osteolysis are common causes for late revisions of knee arthroplasties. Several implant and surgical factors have been implicated in contributing to the development of wear, such as type of bearing surface used, inaccurate articular geometry, and poor knee kinematics. In addition, patient-related factors, such as younger age and higher activity levels, may also contribute to wear. Our purpose was to evaluate and compare the effect of these variables on wear rates following knee arthroplasty. Recently, technological advancements have been aimed at reducing the incidence of wear by improving the PE manufacturing process, creating implants that minimize contact stresses, and refining our surgical techniques. Furthermore, the development of newer highly cross-linked PEs (HXLPEs) and the introduction of additives, such as vitamin E, to the PEs may improve overall implant survivorship. As a result, with the advent of newer implant and PE designs, wear is no longer the most common cause of early failure, though it remains an important factor in limiting long-term implant survivorship. However, there are a few clinical studies evaluating the long-term outcomes of newer HXLPEs and implant designs, with further evaluations necessary to determine the best implant-PE combination for improved knee arthroplasty survivorship.

Prevention and management of venous thromboembolic disease following lower extremity total joint arthroplasty.

Venous thromboembolic disease (VTED) is a devastating complication following lower extremity total joint arthroplasty. Various guidelines have been proposed for VTED prevention, the most prevalent being the American Academy of Orthopaedic Surgeons (AAOS) and the American College of Chest Physicians (ACCP). Although there were disagreements in the previous guidelines, there has recently been concordance with the two organizations. Additionally, there are various new pharmacological agents and mechanical devices being utilized and developed for VTED prevention. Therefore, in this review we aim to: (1) evaluate the current ACCP and AAOS guidelines, (2) discuss new chemoprophylactic agents currently available, (3) report briefly on mechanical compression devices to prevent VTED in patients undergoing lower extremity total joint arthroplasty.

Placing femoral intramedullary nails in severely bowed femurs.

The authors describe a novel technique of anterograde femoral intramedullary nail fixation for hip fracture using the starting guide pin as a blocking screw. This cost-effective technique uses fluoroscopic radiography to ensure the guidewire is within the posterior aspect of the femur on a lateral view, thereby minimizing the risk of anterior cortical femoral fractures.

Percutaneous column fixation and total hip arthroplasty for the treatment of acute acetabular fracture in the elderly.

We used our database of primary total hip arthroplasties to identify those patients who had acetabular fractures fixed with percutaneous screws under the same anesthesia as for the arthroplasty procedure. There were 19 patients with the average follow-up of 22 months. Fourteen patients sustained the fracture secondary to a low-energy trauma, while the remaining patients were involved in a high-energy trauma accident. The mean survival time was calculated to be 2.5 ± 0.6 years for the low-energy group and 4 ± 1.4 years for the high-energy group. We believe that this unique treatment of acetabular fractures has a role in carefully selected patients and provides the necessary reduction and immediate stability of the fracture needed to ensure adequate fit for the acetabular cup in the subsequent THA.

Decreased ratios of lateral to medial patellofemoral forces and pressures after lateral retinacular release and gender knees in total knee arthroplasty.

PURPOSE: To demonstrate that lateral to medial patellofemoral force and pressure ratios could be a surrogate marker of retinacular tension and patellar tracking. METHODS: The patellofemoral forces of six knees from three fresh-frozen half-body female cadavers were evaluated with a capacitive sensor under simulated operative conditions in six staged clinical scenarios: native knees, knee arthroplasty without patellar resurfacing, resurfaced knee and patella, resurfaced knee and patella with lateral release, gender-specific knee arthroplasty with patella resurfacing, and gender-specific knee arthroplasty with lateral release. Maximum force and peak pressure were simultaneously recorded during three to four ranges of motion. Average values were compared between lateral and medial patellofemoral compartments as an objective measure of patellar tracking for the different settings. RESULTS: Significant differences in lateral and medial force and pressure differentials were seen in most scenarios despite clinically normal patellar tracking. Lateral to medial ratios of maximum force and peak pressure significantly increased after TKA (2.9, 2.1) and after patella resurfacing (2.8, 2.6) compared to the native knee (1.6, 1.8). Addition of a lateral release in resurfaced knees decreased the ratio of lateral to medial patellofemoral forces and pressures as did gender knee arthroplasty (1.5 and 1.1, 2 and 1.3, respectively). Pressure and force values most closely resembled the native knee in the resurfaced knee/resurfaced patella with lateral release and in the gender knee arthroplasty scenarios. CONCLUSIONS: Use of lateral to medial patellofemoral force ratios as a surrogate objective marker for patellar tracking was validated in this study by decreasing ratios observed after lateral release in TKA and with gender-specific implants.

Use of blocking screws in intramedullary fixation of subtrochanteric fractures.

Intramedullary fixation is the mainstay of treatment for femur fractures in the adult trauma population. With subtrochanteric fractures, accurate reduction and stable fixation become technically challenging. Adjuvant blocking screws in the proximal fragment can effectively be used to prevent varus and apex anterior malalignment when intramedullary nails are used in these fractures. Blocking screws decrease the canal volume, thereby allowing the intramedullary device to control the proximal segment. This aids in improving alignment between the proximal and distal fragments during reduction. We review the cases of six patients with proximal femur fractures who were treated with intramedullary nailing in conjunction with the placement of blocking screws.

Informed consent: is it always necessary?

Informed consent plays a pivotal role in human clinical research. It serves as a marker for the subject's comprehension of all the pertinent elements of the study. It is also a pledge by the investigator that during the trial, the rights and safety of the subject will be protected. Informed consent attempts to ensure that ethical behaviour will be upheld throughout the study. However, obtaining informed consent from certain vulnerable populations is a challenge, and thus warrants improvement. While informed consent is mandated for almost all clinical trial involving human subjects, there are situations of emergency research and trials with minimal risk that call for a waiver of the consent.

Genome sequence survey identifies unique sequences and key virulence genes with unusual rates of amino Acid substitution in bovine Staphylococcus aureus.

Staphylococcus aureus is a major cause of mastitis in bovine and other ruminant species. We here present the results of a comparative genomic analysis between a bovine mastitis-associated clone, RF122, and the recently sequenced human-associated clones, Mu50 and N315, of Staphylococcus aureus. A shotgun sequence survey of approximately 10% of the RF122 genome identified numerous unique sequences and those with elevated rates of nonsynonymous substitution. Taken together, these analyses show that there are notable differences in the genomes of bovine mastitis-associated and human clones of S. aureus and provide a framework for the identification of specific factors associated with host specificity in this major human and animal pathogen.