Can Preoperative Factors Be Used to Determine Optimal Implant Design for Total Knee Arthroplasty?

INTRODUCTION: Although studies have demonstrated similar outcomes between ultracongruent (UC) and traditional bearings, debate exists regarding the optimum bearing surface. We sought to determine whether preoperative factors may predict use of a UC bearing when compared to a standard cruciate retaining (CR) group. MATERIALS AND METHODS: The study cohort consisted of 117 patients who underwent primary total knee arthroplasty (TKA). The implants utilized were either the CR or UC polyethylene components of the Zimmer Persona® Total Knee System. Patient demographics and comorbidities were documented. Intraoperative variables and postoperative outcomes were recorded. We calculated change in tibial slope and femoral condylar offset from pre- to post-surgery and computed the percentage of patients for whom an increase in tibial slope or femoral condylar offset was determined. All dependent variables were compared between patients who received the UC component and those with a CR component using either independent samples t-tests or chi-square test of independence. RESULTS: Thirty-nine patients received a UC insert and 78 patients received a CR insert. Mean length of stay (p=0.017), estimated blood loss (p=0.021), and tourniquet time (p=0.032) were greater for the UC group. Intraoperative implant variables were not different between the groups. However, the proportion of patients for whom tibial slope increased postoperatively was greater for the UC group compared to the CR group (p=0.018). CONCLUSION: Our results showed that no preoperative medical comorbidities or demographic factors predicted use of the UC bearing; however, postoperative tibial slope was increased for a greater number of patients who received the UC implant.

The Repair of an Acute Pathological Subtrochanteric Femur Fracture Using an Adult 3.5-mm Proximal Humerus Locking Plate in an Adolescent Patient: A Case Report.

CASE: We report a novel case of the successful repair of a pathological fracture of a 14-year-old boy's proximal femur using open reduction and internal fixation with an adult 3.5-mm proximal humerus locking plate. CONCLUSION: Successful repair of a pediatric pathologic femur fracture due to an aneurysmal bone cyst may be achieved using an adult proximal humerus locking plate in select patients.

Catastrophic Failure of a MiniHip Femoral Stem: A Case Report.

CASE: The patient is a 63-year-old man who previously underwent a right total hip arthroplasty with the Corin MiniHip femoral stem. Within the first few months postoperatively, he had a fall that resulted in subsidence of his femoral prosthesis and subsequent revision shortly thereafter with a 10-mm skirted cobalt chrome femoral head. Eight years after the index procedure, the patient heard a crack and then collapsed while putting on bicycle shorts. Workup demonstrated a fracture of the stem at the base of the neck of the implant. Femoral stem revision with a diaphyseal engaging, modular implant, and dual mobility hip construct was performed. CONCLUSION: Atraumatic catastrophic failure of the femoral stem implant may be associated with long skirted femoral heads that create excessive bending moments on the stem and revision surgery.

A locking compression plate versus the gold-standard non-locking plate with lag screw for first metatarsophalangeal fusion: A biomechanical comparison.

INTRODUCTION: The treatment of end-stage first metatarso-phalangeal joint (MTP) arthritis has been arthrodesis. A dorsal non-locking plate with a lag screw has been the standard traditional fixation method. This study compares the biomechanical strength of a locking compression plate (LCP) with and without internal compression versus this known gold standard. METHODS: In group 1, six matched pairs of cadaver great toes were used to compare the standard non-locking dorsal plate and 3.5mm lag screw to an anatomic locking compression plate in which a lag screw was utilized rather than the internal compression features of the plate. In group 2, another six matched pairs of cadaver great toes were used to compare the gold standard to the locking compression plate, utilizing the plate's internal compression feature instead of a lag screw. A material testing system (MTS) machine applied loads to the MTP joints and measured displacement and stiffness of the constructs. The stiffness of the constructs (Young's modulus) was calculated from the force-displacement curves, and the displacement was measured. RESULTS: The locking compression plate group that used the compression features of the plate, without the lag screw, had less joint displacement and higher stiffness than control (p<0.05). The same plating construct in which a lag screw was used rather than internal compression of the plate was found to be stiffer than the control (p<0.05), but displacement was not statistically significant. DISCUSSION: The results suggest that a locking compression plate alone provides the stiffest construct for a first MTP joint fusion.

Contemporary trends in evidence-based treatment for acute myocardial infarction.

BACKGROUND: Guidelines for the management of patients with acute myocardial infarction recommend the routine use of 4 effective cardiac medications: angiotensin-converting enzyme inhibitors, aspirin, beta-blockers, and lipid-lowering agents. Limited data are available, however, about the contemporary and changing use of these therapies, particularly from a population-based perspective. The study describes differences in the use of these medications during hospitalization for acute myocardial infarction according to age, gender, and period of hospitalization. METHODS: The study population consisted of 6334 women and men treated at 11 hospitals in the Worcester, Mass, metropolitan area for acute myocardial infarction in 6 annual periods between 1995 and 2005. RESULTS: Increases in the use of all 4 cardiac medications during hospitalization for acute myocardial infarction were noted between 1995 and 2005 for all men and in those of different age strata: less than 65 years (4%-47%); 65 to 74 years (4%-46%); 75 to 84 years (2%-48%); and more than 85 years (0%-23%). Increases in the use of all 4 cardiac medications also were observed in all women and in those of all ages over time (2%-42%); 65 to 74 years (8%-47%); 75 to 84 years (1%-44%); and more than 85 years (1%-44%). CONCLUSION: The present results suggest marked increases over time in the use of evidence-based therapies in patients hospitalized with acute myocardial infarction. Educational efforts to augment the use of these effective cardiac therapies, as well as attempts to identify suboptimally treated groups, remain warranted.