Predicting Instability Risk Following Hemiarthroplasty for Femoral Neck Hip Fractures in Geriatric Patients.

BACKGROUND: Although a rare complication, dislocation following hemiarthroplasty (HA) for a femoral neck hip fracture is associated with increased mortality, readmission, and possible revision surgery. To date many of the specific risk factors have been difficult to demonstrate. Patient factors, surgical factors, as well as morphological factors need to be assessed. Therefore, the purpose of this study was to elucidate the risk factors for dislocation of HA following femoral neck hip fractures in the geriatric population. METHODS: This was a retrospective review of 270 patients who had hip fractures. Medical records between the years 2016 and 2022 informed binomial regression predictive models. The discriminative ability of variables in the final model and acetabular anteversion to predict dislocation was assessed with area under the curve (AUC) estimates. RESULTS: Center edge angle (odds ratio 1.23), abduction angle (odds ratio 1.17), and depth width ratio (2.96e-11) were significant predictors of dislocation (P = .003, .028, and <.001, respectively). Center edge angle and depth width ratio (<44.1 ° and .298), respectively, were cut scores for risk. Dementia had a high discriminative of ability, as did men (AUC = 0.617, 0.558, respectively). Acetabular anteversion was not predictive of dislocation (P = .259) and theorized anteversion safe zones had poor discriminative ability with AUCs of 0.510 and 0.503, respectively. CONCLUSIONS: Morphological factors related to hip dysplasia and a shallow acetabulum, which can be assessed with a radiograph alone, were found to be predictors of instability following HA in the elderly. Hemiarthroplasty implant design and manufacturer, and also acetabular version did not contribute to instability risk.

Lower extremity kinematic and kinetic factors associated with bat speed at ball contact during the baseball swing.

The purpose of this study was to determine which biomechanical variables measured during the baseball swing are associated with linear bat speed at ball contact (bat speed). Twenty collegiate baseball players hit a baseball from a tee into a net. Kinematics were recorded with a motion capture system sampling at 500 Hz and kinetics were measured by force plates under each foot sampling at 1000 Hz. Associations between bat speed, individual joint and segment kinematics, joint moments and ground reaction forces (GRF) were assessed using Pearson correlations and stepwise linear regression. Average bat speed was 30 ± 2 m/s. Lead foot peak vertical (159 ± 29% BW, r = 0.622, P = 0.001), posterior (-57 ± 12% BW, r = -0.574, P = 0.008) and resultant (170 ± 30% BW, r = 0.662, P = 0.001) GRF were all correlated with bat speed. No combination of factors strengthened the relationship to bat speed beyond these individual variables. These results illustrate the role of the lead leg in generating and transferring ground reaction forces through the kinetic chain in order to accelerate the bat. Training to improve bat speed should include both general lower extremity strengthening exercises and sport-specific hitting drills to improve lower extremity force production following lead foot contact.

Resolution of Possible Neurosarcoidosis With Early Initiation of Glucocorticoids in the Acute Inpatient Setting: A Case Report.

Neurosarcoidosis is an autoimmune disorder of unknown etiology. We report a case of a 27-year-old African American male presenting with fever, vomiting, and seizure. Initially, bacterial meningitis was suspected, and empiric antibiotics with dexamethasone were started. Workup revealed negative cultures, leptomeningeal enhancement, and cavitary lung nodules with hilar lymphadenopathy on imaging and elevated angiotensin-converting enzyme levels on cerebrospinal fluid (CSF) analysis. Neurosarcoidosis was then suspected, and a lung biopsy was performed. The results were inconclusive, but the patient's condition improved. He was discharged on prednisone. Our case demonstrates the diagnostic difficulty of neurosarcoidosis while displaying the importance of early initiation of glucocorticoids in the acute inpatient setting.