Implementing and Evaluating a Course-Based Undergraduate Research Experience (CURE) at a Hispanic-Serving Institution

We are examining the impact of a course-based undergraduate research experience (CURE) at a land-grant, Hispanic-serving institution in the southwestern United States. Students in our CURE completed one or two extended research projects over a single semester. Our CURE enrolled a high proportion of underrepresented minority students (70.3%), including 60.2% Hispanic students. One year after CURE completion, 31.5% of CURE students had graduated with a STEM degree, and 54.3% were enrolled in a STEM major. Pre- and postcourse surveys of indicators of persistence including scientific self-efficacy, scientific identity, valuing scientific community objectives, and intention to persist showed positive shifts. Impacts on STEM persistence have implications for the role of our CURE in diversifying the STEM pipeline, particularly for students historically underrepresented in STEM

Fracture of the neck of an uncemented femoral component unrelated to trunnion corrosion

This is the first report, to our knowledge, of a fracture, unrelated to trunnion corrosion, through the midneck of a well-fixed uncemented cobalt-chromium alloy femoral component that had been implanted via a total hip revision arthroplasty 25 years ago. Three years after a second revision for polyethylene wear, the patient noted an acute onset of pain in the left hip. There was no antecedent pain in the hip or thigh. Radiographs and intraoperative findings showed a well-fixed femoral component. Electron microscopic retrieval analysis showed intergranular material cracks. Revision of the femoral component was performed with an extended trochanteric osteotomy. This fracture of the femoral component neck was likely related to metal fabrication techniques, and surveillance of this component may be warranted. Keywords: Femoral component neck fracture, Total hip arthroplasty, Revision, Catastrophic failur

Catastrophic failure of tripolar constrained liners due to backside wear: a novel failure mode

Constrained acetabular liners have been developed for patients who are at high risk for dislocation or who are undergoing revision surgery for recurrent dislocations. We report on 2 cases of failure of tripolar constrained liners due to severe backside polyethylene wear after dissociation of the outer polyethylene liner without dislocation, a mode of failure not previously reported. The backside of the inserts suffered severe polyethylene deformation, wear, and scratching due to dissociation from the locking mechanism. In patients with tripolar constrained liners, radiographic evidence of eccentric wear should be considered as possible occult dissociation of the polyethylene liner within the shell. Conversion to a modular dual mobility liner appears to be a viable solution in this setting. Keywords: Revision total hip arthroplasty, Dislocation, Tripolar constrained liner, Modular dual mobilit

The effect of constraint on post damage in total knee arthroplasty: posterior stabilized vs posterior stabilized constrained inserts

Posterior stabilized constrained (PSC) inserts are intended to provide greater varus-valgus and rotational constraint than conventional PS inserts. We determined whether the added constraint resulted in more damage to the post in PSC compared to PS inserts. Retrieved PSC inserts were matched to retrieved PS inserts from the same manufacturer according to patient age, body mass index, and length of implantation. Surface damage was visually assessed, and 3-D surface deviation from pristine was measured. Damage scores for the PSC posts were significantly greater than those of the PS posts. Surface deviation was significantly greater in the posterior and medial post regions of the PSC inserts. Based on short-term follow-up, our results suggest that added constraint is accompanied by greater polyethylene surface damage

Fracture of the femoral adapter bolt and taper adapter in a modern rotating platform knee arthroplasty

A 58-year-old woman presented with onset of pain associated with a popping sound after a twisting motion 4 years after left total knee revision arthroplasty. She had a complex medical history, including a reported bone cement allergy, and presented to the hospital unable to bear weight. Plain radiographs revealed a broken femoral component, with the femoral metaphyseal sleeve separated from the distal articular component. During surgery, it was observed that the femoral adapter bolt and taper adapter had both fractured. Scanning electron microscopy of the fracture surfaces of the components confirmed that the implant had failed in fatigue, presumably due to high cyclic loads. Failure at this junction has not been described previously. In this type of knee design, we recommend supporting the distal articular component either with bone, augmentation, and/or bone cement to reduce the risk for this mode of failure. Keywords: Total knee arthroplasty, Revision, Implant failure, Modula

Fracture of an S-ROM stem at the sleeve-stem junction

Fracture of a well-ingrown femoral component is a rare and often challenging complication. Modular junctions and sleeve interfaces have been identified as one potential point of weakness with corrosion and fretting being contributing factors to ultimate femoral component fracture. Stem fractures at the sleeve interface were reported occasionally for the proximal ingrowth modular Emperion System (Smith and Nephew, Memphis, TN). However, this failure mechanism has been reported infrequently, often associated with corrosion at the modular junction, for the similarly designed S-ROM system (DePuy Orthopedics Inc., Warsaw, IN). We present the case of a 52-year-old patient, with a body weight of 84 kg (185 lbs) and a body mass index of 30.6 kg/m2, who suffered a fatigue fracture of a 14 × 09 × 130 mm S-ROM stem 42 months after implantation. The present study presents the results of the surface analysis, discusses possible failure mechanisms, provides treatment guidelines, and a review of the literature revealing 15 cases of failure at the level of the stem-sleeve junction. In particular, modifiable risk factors for potential stem failure, including stem diameter, stem offset, and the resulting cantilever bending forces on the proximal sleeve-stem junction, are discussed in detail. Keywords: Stem fracture, Removal technique, Breakage, Failure, Corrosio

Osteoarthritis Classification Scales: Interobserver Reliability and Arthroscopic Correlation

The MARS Group* Background: Osteoarthritis of the knee is commonly diagnosed and monitored with radiography. However, the reliability of radiographic classification systems for osteoarthritis and the correlation of these classifications with the actual degree of confirmed degeneration of the articular cartilage of the tibiofemoral joint have not been adequately studied. Methods: As the Multicenter ACL (anterior cruciate ligament) Revision Study (MARS) Group, we conducted a multicenter, prospective longitudinal cohort study of patients undergoing revision surgery after anterior cruciate ligament reconstruction. We followed 632 patients who underwent radiographic evaluation of the knee (an anteroposterior weight-bearing radiograph, a posteroanterior weight-bearing radiograph made with the knee in 45°of flexion [Rosenberg radiograph], or both) and arthroscopic evaluation of the articular surfaces. Three blinded examiners independently graded radiographic findings according to six commonly used systems-the Kellgren-Lawrence, International Knee Documentation Committee, Fairbank, Brandt et al., Ahlbäck, and Jäger-Wirth classifications. Interobserver reliability was assessed with use of the intraclass correlation coefficient. The association between radiographic classification and arthroscopic findings of tibiofemoral chondral disease was assessed with use of the Spearman correlation coefficient. Results: Overall, 45°posteroanterior flexion weight-bearing radiographs had higher interobserver reliability (intraclass correlation coefficient = 0.63; 95% confidence interval, 0.61 to 0.65) compared with anteroposterior radiographs (intraclass continue