Larger-diameter trunnions and bolt-reinforced taper junctions are associated with less tribocorrosion in reverse total shoulder arthroplasty.

BACKGROUND: Morse taper junction tribocorrosion is recognized as an important failure mode in total hip arthroplasty. Although taper junctions are used in almost all shoulder arthroplasty systems currently available in the United States, with large variation in design, limited literature has described comparable analyses of taper damage in these implants. In this study, taper junction damage in retrieved reverse total shoulder arthroplasty (RTSA) implants was assessed and analyzed. METHODS: Fifty-seven retrieved RTSAs with paired baseplate and glenosphere components with Morse taper junctions were identified via database query; 19 of these also included paired humeral stems and trays or spacers with taper junctions. Components were graded for standard damage modes and for fretting and corrosion with a modified Goldberg-Cusick classification system. Medical records and preoperative radiographs were reviewed. Comparative analyses were performed assessing the impact of various implant, radiographic, and patient factors on taper damage. RESULTS: Standard damage modes were commonly found at the evaluated trunnion junctions, with scratching and edge deformation damage on 76% and 46% of all components, respectively. Fretting and corrosion damage was also common, observed on 86% and 72% of baseplates, respectively, and 23% and 40% of glenospheres, respectively. Baseplates showed greater moderate to severe (grade ≥ 3) fretting (43%) and corrosion (27%) damage than matched glenospheres (fretting, 9%; corrosion, 13%). Humeral stems showed moderate to severe fretting and corrosion on 28% and 30% of implants, respectively; matched humeral trays or spacers showed both less fretting (14%) and less corrosion (17%). On subgroup analysis, large-tapered implants had significantly lower summed fretting and corrosion grades than small-tapered implants (P < .001 for both) on glenospheres; paired baseplate corrosion grades were also significantly lower (P = .031) on large-tapered implants. Factorial analysis showed that bolt reinforcement of the taper junction was also associated with less fretting and corrosion damage on both baseplates and glenospheres. Summed fretting and corrosion grades on glenospheres with trunnions (male) were significantly greater than on glenospheres with bores (female) (P < .001 for both). CONCLUSIONS: Damage to the taper junction is commonly found in retrieved RTSAs and can occur after only months of being implanted. In this study, tribocorrosion predominantly occurred on the taper surface of the baseplate (vs. glenosphere) and on the humeral stem (vs. tray or spacer), which may relate to the flexural rigidity difference between the titanium and cobalt-chrome components. Bolt reinforcement and the use of large-diameter trunnions led to less tribocorrosion of the taper junction. The findings of this study provide evidence for the improved design of RTSA prostheses to decrease tribocorrosion.

Factors Motivating Medical Students in Selecting a Career Specialty: Relevance for a Robust Orthopaedic Pipeline.

INTRODUCTION: Selection of a career specialty by medical students is a complex and individualized decision. Our goals were to understand the factors that influenced medical students in selecting their career specialty, identify the stage at which this decision was made, and understand the role of demographics, mentors, and curricula in this process. METHODS: Medical students from 10 institutions participated in a web-based survey. Results were stratified by sex, race/ethnicity, and level of interest in orthopaedic surgery. RESULTS: A total of 657 students responded to the survey. Specialty content (mean rating, 8.4/10) and quality of life/lifestyle/stress level (7.5/10) were the primary motivating factors in selecting a specialty. Interest in orthopaedic surgery was lower in women than in men (2.7 versus 3.9; P < 0.01) and was equivalent among race/ethnicity groups. Although 27% of students reported moderate or extensive medical school curriculum exposure to orthopaedics, this education did not sway them toward the specialty. CONCLUSIONS: Levels of interest in orthopaedics among medical students may be lower than generally assumed. Increasing the attractiveness of the specialty will require a multifaceted approach, including recognition of lifestyle factors, adjustments in the orthopaedic clerkship to make the specialty more appealing, mentorship by orthopaedic faculty, and conversion of high levels of interest in the specialty among minority medical students into successful residency applications. LEVEL OF EVIDENCE: IV.

Comparing the Incidence and Clinical Data for Simultaneous Bilateral Versus Unilateral Total Hip Arthroplasty in New York State Between 1990 and 2010.

A New York State database reported information on all total hip arthroplasty cases between 1990 and 2010 comparing unilateral (242,588 cases) to simultaneous bilateral (4538 cases) procedures. Our data showed that the population incidence of this surgery increased 120.2% over twenty years, yet the proportionate number of simultaneous cases has decreased. Simultaneous procedures were found to occur more commonly in younger patients with private insurance. In addition, bilateral procedures showed an increase in PE, DVT, length of stay, and discharge to rehab facilities; whereas mortality and blood transfusions compared to unilateral procedures showed no difference.

Revision total joint arthroplasty: the epidemiology of 63,140 cases in New York State.

Recent evidence suggests a substantial rise in the number of revision total joint arthroplasty (TJA) procedures performed. The New York State SPARCS inpatient database was utilized to identify revision total shoulder, knee, and hip arthroplasty procedures between 1993 and 2010. Yearly incidence and related epidemiology were analyzed. A total of 1,806 revision TSA, 26,080 revision TKA, and 35,254 revision THA cases were identified. The population-based incidence of these procedures increased 288%, 246%, and 44% respectively (P<0.001). Revision burden for hip arthroplasty decreased from 16.1% in 2001 to 11.5% in 2010 (P<0.001). The rates of revision TSAs and TKAs increased at a substantially faster rate than that of revision THAs. Revision burden for hip arthroplasty steadily has decreased since 2001.

Femoral neck fractures in New York State. Is the rate of THA increasing, and do race or payer influence decision making?

OBJECTIVES: To evaluate the treatment trends for femoral neck fractures in New York State over the past 10 years. METHODS: The Statewide Planning and Research Cooperative System database from the New York State Department of Health was used to identify patients who sustained femoral neck fractures from 2000 to 2010. Multivariate logistic regression analysis was performed with the dependent variable being total hip arthroplasty (THA) versus hemiarthroplasty (HA) and independent variables being age, sex, race, insurance type, and comorbidity index. RESULTS: From 2000 to 2010, there were 44,425 patients admitted to New York State hospitals with femoral neck fractures, of which 86% occurred in patients older than 70. Of the total, 73.5% were treated with HA, 19.5% with internal fixation (IF), and 7% with THA. The overall rate of treatment with THA increased slightly, but this was not statistically significant (P = 0.11), and it only increased for patients younger than 70 years. The rate of HA increased significantly from 69.9% to 75.4% (P < 0.001), and the rate of IF showed a statistically significant reduction from 21.9% to 16.8% (P < 0.001). Results of the multivariate logistic regression analysis showed that for every 10-year increase in age, there was a 31% reduction in treatment with THA compared with HA. White patients were just as likely to receive THA as non-whites, and patients with private insurance were 41% more likely to receive THA than self-pay and federally insured patients. CONCLUSIONS: The rate that THA is being performed as treatment of femoral neck fractures is increasing for patients younger than 70 years but decreasing for patients older than 80 years. The rate of IF is decreasing. Patients with private insurance were more likely to receive THA than patients with federal insurance. LEVEL OF EVIDENCE: Prognostic Level II. See Instructions for Authors for a complete description of levels of evidence.