A radiologic determination of the different screw cutting patterns in cut and uncut orthopedic cortical screws using a novel imaging technique.

OBJECTIVE: We hypothesize that cut screws will deform in a manner that increases the core and outer diameters of the screw hole compared to uncut controls, and effects will be more pronounced in titanium screws. MATERIALS AND METHODS: We used biomechanical polyurethane foam blocks to simulate cortical bone. We organized four groups of stainless steel and titanium cut and uncut screws. Blocks were fitted with a jig to ensure perpendicular screw insertion. We imaged the blocks using digital mammography and measured them using PACS software. Power analysis determined a power of 0.95 and an alpha error of 0.05. RESULTS: Highly statistically significant differences in core diameter were found after cutting stainless steel and titanium screws. Cutting stainless steel screws increased core diameter by 0.30 mm (95% CI, 0.16 to 0.45; p < .001). Titanium screws' core diameter increased by 0.45 mm (95% CI, 0.30 to 0.61; p < .001). No significant differences were found in the outer diameters of stainless steel and titanium screws after cutting. CONCLUSION: Titanium and stainless steel screw tracts demonstrated screw core diameter and screw thread pattern deformation after cutting. Titanium screws demonstrated more significant effects.

A history of shoulder instability is more common in young patients undergoing total shoulder arthroplasty.

BACKGROUND: Previous studies have shown an association between shoulder instability and the development of glenohumeral arthritis leading to total shoulder arthroplasty (TSA). The primary goal of this study was to evaluate if a history of shoulder instability was more common in patients aged <50 years undergoing TSA. The secondary objective was to determine if a history of prior surgical stabilization is more common in patients aged <50 years undergoing TSA. METHODS: Using the military health system data repository (MDR) and the Military Analysis and Reporting Tool (M2), we identified 489 patients undergoing primary TSA from October 1, 2013, to May 1, 2020, within the Military Health System (MHS). Patients aged <50 years were matched 1:2 with patients aged ≥50 years based on sex, race, and military status, with the final study population comprising 240 patients who underwent primary TSA during the study period. Electronic medical records were examined, and factors showing univariate association (P < .2) were included in a binary logistic regression analysis to determine associations between demographic or clinical factors and TSA prior to age 50 years. RESULTS: The groups differed significantly in shoulder arthritis subtype, with the older group having significantly more primary osteoarthritis (78% vs. 51%, P < .001). The younger group had significantly more patients with a history of shoulder instability (48% vs. 12%, P < .001), prior ipsilateral shoulder surgery of any type (74% vs. 34%, P < .001), and prior ipsilateral shoulder stabilization surgery (31% vs. 5%, P < .001). In the resultant logistic regression model, a history of shoulder instability (OR 5.0, P < .001) and a history of any prior ipsilateral shoulder surgery (OR 3.5, P < .001) were associated with TSA prior to the age of 50 years. CONCLUSIONS: Shoulder instability is a risk factor for TSA before age 50 years. It is unclear how surgical stabilization influences the development of secondary glenohumeral arthritis in shoulder instability. Patients should be counseled that recurrent instability could lead to earlier TSA, regardless of whether surgical stabilization is performed.

Detection of Traumatic Ankle Arthrotomies: Computed Tomography Scan Versus Saline Load Test.

OBJECTIVE: Periarticular wounds present a common diagnostic dilemma for emergency providers and orthopedic surgeons because traumatic arthrotomies (TA) often necessitate different management from superficial soft tissue wounds. Historically, TA have been diagnosed with the saline load test (SLT). Computed tomography (CT) scan has been studied as an alternative to SLT in diagnosing TA in several joints, but there are limited data specifically pertaining to the ankle. This study aimed to compare the ability of a CT scan to identify an ankle TA versus a traditional SLT. The hypothesis was that there would be no significant difference between a CT scan and SLT in diagnosing ankle TA in a cadaveric model. METHODS: This cadaveric study used 10 thawed fresh-frozen cadaveric ankles. A baseline CT scan was performed to ensure no intra-articular air existed before simulated TA. After the baseline CT, a 1 cm TA was created in the anterolateral arthroscopy portal site location. The ankles then underwent a postarthrotomy CT scan to evaluate for the presence of intra-articular air. After the CT scan, a 30 mL SLT was performed using the anteromedial portal site location. RESULTS: After arthrotomy, intra-articular air was visualized in 7 of 10 cadavers in the postarthrotomy CT scan. All the ankles had fluid extravasation during the SLT with <10 mL of saline. The sensitivity of the SLT for TA was 100% versus 70% for the CT scan. CONCLUSIONS: The SLT was more sensitive in diagnosing 1-cm ankle TA than a CT scan in a cadaveric model.

Olanzapine treatment of adolescent rats alters adult reward behaviour and nucleus accumbens function.

Antipsychotic drugs are increasingly used in children and adolescents to treat a variety of psychiatric disorders. However, little is known about the long-term effects of early life antipsychotic drug (APD) treatment. Most APDs are potent antagonists or partial agonists of dopamine (DA) D2 receptors; atypical APDs also have multiple serotonergic activities. DA and serotonin regulate many neurodevelopmental processes. Thus, early life APD treatment can, potentially, perturb these processes, causing long-term behavioural and neurobiological sequelae. We treated adolescent, male rats with olanzapine (Ola) on post-natal days 28-49, under dosing conditions that approximate those employed therapeutically in humans. As adults, they exhibited enhanced conditioned place preference for amphetamine, as compared to vehicle-treated rats. In the nucleus accumbens core, DA D1 receptor binding was reduced, D2 binding was increased and DA release evoked by electrical stimulation of the ventral tegmental area was reduced. Thus, adolescent Ola treatment enduringly alters a key behavioural response to rewarding stimuli and modifies DAergic neurotransmission in the nucleus accumbens. The persistence of these changes suggests that even limited periods of early life Ola treatment may induce enduring changes in other reward-related behaviours and in behavioural and neurobiological responses to therapeutic and illicit psychotropic drugs. These results underscore the importance of improved understanding of the enduring sequelae of paediatric APD treatment as a basis for weighing the benefits and risks of adolescent APD therapy, especially prophylactic treatment in high-risk, asymptomatic patients.