Factors Associated With COVID-19 Vaccine Hesitancy in Rheumatology Outpatients in New York City.

OBJECTIVE: The aim of this study was to measure COVID-19 vaccine hesitancy among rheumatology outpatients from an early COVID-19 "hotspot" during the initial period of vaccine availability. METHODS: In March 2021, a Web-based survey was sent to 7505 adults seen at a Rheumatology Division in New York City. We evaluated characteristics associated with 3 categories of COVID-19 vaccination status: declined, undecided, and willing/already received. We used multinomial logistic regression models to calculate relative risk ratios assessing predictors of vaccination status. RESULTS: Among 2384 (32%) respondents (80% female, 87% White, 59% with systemic rheumatic disease), 2240 (94.0%) were willing/already received COVID-19 vaccination, 88 (3.7%) were undecided, and 56 (2.3%) declined. Compared with those willing/already vaccinated, those declining or undecided were younger, more likely identified as Black or Hispanic/Latinx, and had lower household income and educational attainment. Immunosuppressive medication use did not differ among groups. After multivariable adjustment, every 1-year increase in age was associated with a 0.96 lower relative risk of declining or being undecided versus willing/already vaccinated. Respondents identifying as Black versus White had a higher relative risk ratio of being undecided (4.29 [95% confidence interval, 1.96-9.36]), as did those identifying as Hispanic/Latinx versus non-Hispanic/non-Latinx (2.81 [95% confidence interval, 1.29-6.09]). Those declining vaccination were least likely to believe in general vaccine importance or the safety and efficacy of the COVID-19 vaccine. CONCLUSIONS: Among rheumatology patients in New York City with and without systemic rheumatic disease, COVID-19 vaccine uptake was high after its initial availability. Sociodemographic but not medication-related factors were associated with vaccine hesitancy; these findings can inform future rheumatology vaccination programs.

Deep-learning-reconstructed high-resolution 3D cervical spine MRI for foraminal stenosis evaluation.

OBJECTIVE: To compare standard-of-care two-dimensional MRI acquisitions of the cervical spine with those from a single three-dimensional MRI acquisition, reconstructed using a deep-learning-based reconstruction algorithm. We hypothesized that the improved image quality provided by deep-learning-based reconstruction would result in improved inter-rater agreement for cervical spine foraminal stenosis compared to conventional two-dimensional acquisitions. MATERIALS AND METHODS: Forty-one patients underwent routine cervical spine MRI with a conventional protocol comprising two-dimensional T2-weighted fast spin echo scans (2 axial planes, 1 sagittal plane), and an isotropic-resolution three-dimensional T2-weighted fast spin echo scan reconstructed over a 4-h time window with a deep-learning-based reconstruction algorithm. Three radiologists retrospectively assessed images for the degree to which motion artifact limited clinical assessment, and foraminal and central stenosis at each level. Inter-rater agreement was analyzed with weighted Fleiss's kappa (k) and comparisons between two-dimensional and three-dimensional sequences were performed with Wilcoxon signed-rank test. RESULTS: Inter-rater agreement for foraminal stenosis was "substantial" for two-dimensional sequences (k = 0.76) and "excellent" for the three-dimensional sequence (k = 0.81). Agreement was "excellent" for both sequences (k = 0.85 and 0.83) for central stenosis. The three-dimensional sequence had less perceptible motion artifact (p ≤ 0.001-0.036). Mean total scan time was 10.8 min for the two-dimensional sequences, and 7.3 min for the three-dimensional sequence. CONCLUSION: Three-dimensional MRI reconstructed with a deep-learning-based algorithm provided "excellent" inter-observer agreement for foraminal and central stenosis, which was at least equivalent to standard-of-care two-dimensional imaging. Three-dimensional MRI with deep-learning-based reconstruction was less prone to motion artifact, with overall scan time savings.

Coach Education Improves Adherence to Anterior Cruciate Ligament Injury Prevention Programs: A Cluster-Randomized Controlled Trial.

OBJECTIVE: To determine the effect of an educational workshop on adherence to neuromuscular training (NMT) among high-school coaches. DESIGN: Cluster-randomized controlled trial. SETTING: High school. PARTICIPANTS: A total of 21 teams in 8 high schools (unit of randomization) were randomized to the intervention or control group. Twelve boys' and 9 girls' teams in a variety of sports were enrolled. INTERVENTION: Coaches in the intervention group participated in a 60-minute education workshop to teach effective implementation of a NMT program and also received print materials. Coaches in the control group received the same print materials. MAIN OUTCOME MEASURES: Eight data collectors were trained to observe each team's practice/game 2 to 3 times a week. They completed a study questionnaire to identify the NMT exercise and whether the coach (1) delivered exercise instructions and (2) provided alignment cues (both yes/no). RESULTS: A total of 399 practices/games were observed over 2 seasons. A greater proportion of coaches in the intervention group provided alignment cues to correct improper technique compared with the control group {difference = 0.04 [95% confidence interval (CI), 0.01-0.07], P = 0.006}. There was a similar proportion of coaches in the intervention and control groups who provided exercise instructions [difference = 0.01 (95% CI, -0.02 to 0.04), P = 0.44]. More coaches in the intervention group completed a full NMT program [OR = 4.62 (1.22, 17.50), P = 0.02]. CONCLUSIONS: Coach education can improve adherence to a NMT program and delivery of alignment cues. Coaches should receive in-person training on NMT and how to deliver alignment cues to their athletes while performing the exercises.

What Factors Are Associated with Patient-reported Outcome Measure Questionnaire Completion for an Electronic Shoulder Arthroplasty Registry?

BACKGROUND: There has been an increase in the use of electronic systems to collect patient-reported outcome measures. There is limited data on the added value of electronic reporting on increasing patient response proportions and little knowledge of which patients are more likely to respond. QUESTIONS/PURPOSES: (1) What proportion of patients completed patient-reported outcome questionnaires at baseline and at 1 year and 2 years of follow-up after shoulder arthroplasty, and what methods did they use to complete these questionnaires (either automated or manual data collection)? (2) What factors were associated with questionnaire completion? METHODS: Our shoulder arthroplasty registry from a high-volume, tertiary care center implemented an electronic platform to collect patient-reported outcomes. A total of 2128 patients underwent shoulder arthroplasty between 2016 and 2019. Patients without an email address on file were excluded; 90% (1907 of 2128) of patients were included in the study. The population was 50% women (954 of 1907) with a mean age of 67 ± 9 years. A query was performed to determine whether patients completed questionnaires by either automated or manual data collection at baseline and 1 year and 2 years of follow-up after shoulder arthroplasty. In a logistic regression analysis, patient factors (such as demographics, education, and living arrangements) were evaluated for their association with whether patients completed these questionnaires. RESULTS: The proportion of questionnaire completion at baseline, 1 year, and 2 years were 72% (1369 of 1907), 47% (456 of 972), and 33% (128 of 393), respectively. Of the patients who completed their questionnaires, 63% (868 of 1369) did so through automated emails at baseline, 84% (381 of 456) did so at 1 year, and 81% (103 of 128) did so at 2 years. The remainder completed their questionnaires through manual data collection with a research assistant: 37% (501 of 1369) at baseline, 16% (75 of 456) at 1 year, and 19% (25 of 128) at 2 years. After controlling for potentially confounding variables like patient demographics, college education, and living arrangements, women were less likely to complete baseline questionnaires than men (odds ratio 0.78 [95% confidence interval 0.62 to 0.99]; p = 0.04), and white patients (OR 1.6 [95% CI 1.05 to 2.44]; p = 0.03) were more likely than nonwhite patients to have complete baseline questionnaires. At 2 years of follow-up, patients with a college education (OR 2.06 [95% CI 1.14 to 3.71]; p = 0.02), those who lived alone (OR 2.11 [95% CI 1.13 to 3.94]; p = 0.02), and those who had higher baseline Shoulder Activity Scale scores (OR 1.05 [95% CI 1.00 to 1.11]; p = 0.04) were more likely to have complete questionnaires than those without a college education, those who lived with other people, and those with lower SAS scores, respectively. CONCLUSION: The challenges of adopting an online platform include low follow-up proportions and the need for manual assistance by a research assistant to increase patient completion of questionnaires. CLINICAL RELEVANCE: The knowledge of which patient characteristics are associated with a higher likelihood of completing questionnaires has implications for targeted follow-up or representative sampling of the population in a registry. Populations that are less likely to respond may require more effort to reach to prevent exacerbating health outcome disparities. Random sampling with upweighting of hard-to-reach populations may also provide a solution to achieve a representative population of patients undergoing shoulder arthroplasty.

Patellofemoral Arthroplasty Surgical Technique: Lateral or Medial Parapatellar Approach.

BACKGROUND: Patellofemoral arthroplasty (PFA) is an emerging treatment for patients with isolated patellofemoral compartment osteoarthritis. The medial parapatellar approach is the standard arthrotomy but has been shown in total knee arthroplasty to damage the patellar blood supply and increase postoperative patellar instability. The lateral parapatellar approach is an alternative that may reduce the risk of these outcomes. The purpose of this study is to compare the radiographic measures of patellar tracking and patient-reported outcomes of the medial and lateral parapatellar approaches in PFA. METHODS: Between 2012 and 2019, a retrospective review was performed of 136 knees undergoing PFA at a single institution. Patients were separated by preoperative congruence angle and then surgical approach into 3 cohorts. Preoperative and postoperative patellar tilt and congruence angle were measured. Preoperative and minimum 6-month postoperative patient-reported outcomes scores were collected. RESULTS: There were no significant differences in the mean postoperative congruence angle and postoperative patient-reported outcomes among the 3 cohorts. Mean postoperative patellar tilt was normalized only in the abnormal congruence angle/lateral approach group to 2.80° (standard error, 1.85). CONCLUSION: Congruence angle was improved regardless of surgical approach. Patellar tilt was normalized only for the lateral approach in patients with abnormal preoperative congruence angle. There were no significant differences in preoperative and postoperative scores between groups except for preoperative 12-item Short Form Mental Health Survey scores. This study supports that the lateral approach offers improved postoperative patellar tilt compared to a medial approach for PFA while achieving similar patient-reported outcomes.

Supply and demand: Will we have enough vascular surgeons by 2030?

The increase in prevalence of certain cardiovascular risk factors increases susceptibility to vascular disease, which may create demand for surgical intervention. In our study, data collected by the American Association of Medical Colleges Physician Specialty Databook of 2012, the United States Census Bureau, and other nationwide organizations were referenced to calculate future changes in vascular surgeon supply and prevalence of people at risk for vascular disease. In 2010, there were 2853 active vascular surgeons. By 2040, the workforce is expected to linearly rise to 3573. There will be an exponential rise in people with cardiovascular risk factors. Adding to concern, in 2030, an estimated 3333 vascular surgeons will be available for 180,000,000 people with at least one risk factor for peripheral arterial disease. The paucity of properly trained surgeons entering the workforce needs to be addressed before this shortage becomes a larger burden on healthcare providers and governmental spending.

Independent data collectors decrease bias in the measurement of adherence to anterior cruciate ligament injury prevention programs.

OBJECTIVES: Studies on adherence to neuromuscular training (NMT) for anterior cruciate ligament (ACL) injury prevention are frequently biased due to the use of self-reporting by coaches or the athletes themselves. Few NMT studies use data collectors (aside from the athletes or the individuals administering the NMT program) to decrease bias when assessing the adherence of coaches and sports teams. We hypothesized that the use of a data collector who is independent of the team to evaluate adherence to NMT programs would be reliable. METHODS: In a prior a cluster-randomized controlled trial evaluating adherence to NMT training trial, twelve boys' and nine girls' high school athletic teams in a variety of sports were enrolled. Eight data collectors (unaffiliated with the NMT program) were hired specifically to record adherence of the athletes to the NMT exercises at each team's warm-ups 2-3 times a week, prior to practices and games. In addition to the data collectors, a control group of independent observers made visits throughout the season to also record adherence (solely for the purpose of this study, alongside the data collectors and in the same fashion) in order to evaluate the data collectors' performance and determine inter-observer reliability. The inter-observer reliability between data collectors and independent observers was measured using the Kappa statistic. RESULTS: A total of 399 warm-ups for practices or games were observed by data collectors to obtain adherence data. Independent observers also measured adherence at 58 practices or games for inter-observer reliability. Exercise instruction and alignment cues for 29 different exercises were analysed. The Kappa values ranged from 0.63 to 1.0, indicating substantial to perfect agreement. The overall Kappa values of 0.89 and 0.90 for exercise instruction and alignment cues, respectively, indicated almost perfect agreement. CONCLUSION: The use of a data collector who is independent of the team to evaluate adherence to NMT programs (rather than athlete or coach self-reporting), was shown to be a reliable method for measurement of adherence in studies of NMT for injury prevention. Avoiding self-reporting in adherence research to NMT training may decrease bias. LEVEL OF EVIDENCE: I.

A Controlled Trial of the Effects of Neuromuscular Training on Physical Performance in Male and Female High School Athletes.

BACKGROUND: Neuromuscular training (NMT) has demonstrated efficacy as an intervention to decrease the risk of anterior cruciate ligament injuries and improve sports performance. The effect of this training on the mechanisms that contribute to improved physical performance has not been well defined. HYPOTHESIS: Athletes in the NMT group will have better mechanisms of fundamental movements and agility tests that may contribute to improved sports performance. STUDY DESIGN: Prospective cohort study. LEVEL OF EVIDENCE: Level 2. METHODS: Eight high school teams (111 athletes, 53% male, mean age 16 years) participated, with half performing NMT. Physical performance was measured using the dorsaVi ViPerform system, a US Food and Drug Administration-cleared wireless sensor system. Agility was assessed using a timed 3-cone test. Independent sample t tests were used to compare differences between the intervention and control groups. RESULTS: Matched pre- and postseason data were collected from 74 athletes after excluding athletes with injury and those lost to follow-up. Significant improvements were observed in the NMT group for loading/landing speed ratios during a single-leg hop test (right lower extremity = -0.19 [-0.37, 0.03], P = 0.03 and left lower extremity = -0.27 [-0.50, -0.03], P = 0.03). The control group had lower ground reaction forces compared with the NMT group (P < 0.02), while significant improvements were found in the NMT group for initial peak acceleration (P < 0.02) and cadence (P = 0.01) during a straight-line acceleration/deceleration test. For the 3-cone agility test, the postseason time decreased compared with preseason in the NMT group, whereas the time for the control group increased (-0.37 s vs 0.14 s, P < 0.00). CONCLUSION: The results demonstrate that NMT administered by sports medicine clinicians can significantly improve some physical performance of fundamental movements in high school athletes. CLINICAL RELEVANCE: Coaches should be trained to effectively deliver NMT in order to improve sports performance.

The Effects of Arthroscopic Labral Repair on Patient-Reported Outcomes in the Setting of Periacetabular Osteotomy.

BACKGROUND: It is currently unknown whether the addition of arthroscopic labral repair in the setting of periacetabular osteotomy (PAO) provides any clinical benefit. PURPOSE/HYPOTHESIS: The purpose of this study was to compare outcomes of patients who underwent arthroscopic labral repair concomitantly with PAO versus patients who underwent PAO alone. We hypothesized that there would be no difference in patient-reported outcome measures (PROMs) between the cohorts. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Patients undergoing PAO from a single-center prospective hip preservation registry were eligible for this study if they completed pre- and postoperative PROMs (minimum, 1 year). PROMs were collected at 1 year, 2 years, and latest follow-up at 6.05 years for PAO group and 4.2 years for scope/PAO group. The study group consisted of 53 patients who underwent arthroscopic labral repair at the time of their PAO, and the comparison group consisted of 170 patients who underwent PAO alone. A subset of the PAO group who had radiologic evidence of a detached labral tear (n = 33) was also compared with the rest of the PAO-alone group. PROMs were compared at every time point for both groups as well as the subset of patients who underwent PAO alone despite a labral tear. RESULTS: The mean follow-up of all patients was 2 years (range, 1-6 years). Overall, 85.2% of the PAO group and 85.7% of the scope/PAO group met the minimal clinically important difference for either the modified Harris Hip Score (mHHS) or the International Hip Outcome Tool (iHOT-33) at the most recent follow-up. There was no difference in improvement between groups (mHHS, P = .670; iHOT-33, P = .944). Patients who had a radiologically diagnosed detached labral tear and underwent PAO alone had no difference in outcomes when compared with the rest of the PAO cohort (mHHS, P = .981; iHOT-33, P = .909). CONCLUSION: There was no significant benefit measured by PROMs at follow-up for concomitant arthroscopic labral repair in the setting of PAO.

The use of image analysis software increases the accuracy of the periacetabular osteotomy fragment placement.

The purpose of this study was to report on the use of image analysis technology to enhance accuracy of intra-operative imaging and evaluation of periacetabular osteotomy (PAO) correction. This was a retrospective study reporting on the first 25 cases of PAO performed with the use of an image analysis tool. This technology was used intra-operatively to assess the position of the supine coronal image in comparison to pre-operative standing images using a ratio of pelvic tilt (PT). Intra-operative PT, Tönnis angle, lateral center-edge angle (LCEA) and anterior wall index were compared to post-operative images. Post-operative radiographic parameters in the study group were compared with a control group of PAO cases performed prior to the implementation of the new software. The image analysis software was able to obtain intra-operative supine imaging that was equivalent to pre-operative standing imaging. When comparing the PAOs performed with the use of the software versus those without, the study group trended toward being more likely within the surgeon's defined target range of radiographic values, which was statistically significant for LCEA. This tool can be used to assure the surgeon that the intra-operative image being used for surgical decision-making is representative of the functional radiograph. PAOs performed with the use of this technology showed enhanced accuracy of surgical correction for the parameters within our defined target ranges. This may increase the ability of the surgeon to place the acetabular fragment more precisely within his or her goal parameters for acetabular reorientation correction.

Female Residents Give Themselves Lower Scores Than Male Colleagues and Faculty Evaluators on ACGME Milestones.

OBJECTIVE: Orthopedic surgery is one of the specialties with the lowest number of women residents and practicing surgeons. The gender discrepancy in orthopedic residency training may drive a competency bias. We asked whether female orthopedic surgery residents score themselves lower on the Accreditation Council for Graduate Medical Education (ACGME) Milestones than their male counterparts, and lower than their faculty evaluators. DESIGN: We conducted a retrospective review of ACGME Milestone data from faculty and residents over a 4-year period. The data were analyzed using a snapshot of PGY2 (n = 20 residents) and PGY4 (n = 19 residents) scores, and using a Generalized Estimation Equation (GEE) to account for additional data points from the same residents over the 4-year data collection period. SETTING: Assessment scores were compiled from a single orthopedic surgery residency at Oregon Health & Science University from 2014 to 2017. PARTICIPANTS: The residency program has 5 residents in each program year (PGY1 through PGY5); a total of 25 residents during each year of the study were included. RESULTS: On average, female residents scored themselves lower than both their male counterparts and their faculty mentors. Female PGY2 self-evaluation scores were lower than males in both patient care (p = 0.005) and medical knowledge (p < 0.001). When the GEE model was applied to 99 responses from 41 residents over a 4-year period, there were no gender-related differences in resident self-evaluation scores and in faculty scores of male and female residents, with the exception of meniscal tear. For this milestone, faculty rated female residents lower than males. Furthermore, the differences between faculty evaluation scores and resident self-evaluation scores were significantly lower for males than for females for 4 of the clinical domains, as well as the systems-based practice domains of cost and communication. CONCLUSIONS: Our results indicate female residents are at risk for a competency bias during training, as reflected by evaluations using the ACGME Milestones.

The impact of Charlson and Elixhauser comorbidities on patient outcomes following shoulder arthroplasty.

AIMS: To investigate the impact of the Charlson and Elixhauser comorbidity indices on patient-reported outcomes measures (PROMs) following shoulder arthroplasty. METHODS: Patients undergoing total shoulder arthroplasty (TSA), reverse shoulder arthroplasty (RSA), or hemiarthroplasty (HA) from 2016 to 2018 were identified, along with the Charlson and Elixhauser comorbidities listed as their secondary diagnoses in the electronic medical records. Patients were matched to our institution's registry to obtain their PROMs, including shoulder-specific (American Shoulder and Elbow Society (ASES) and Shoulder Activity Scale (SAS)) and general health scales (12-Item Short Form Survey (SF-12) and Patient-Reported Outcomes Measurement Information System-Pain Interference). Linear regression models adjusting for age and sex were used to evaluate the association between increasing number of comorbidities and PROM scores. A total of 1,817 shoulder arthroplasties were performed: 1,017 (56%) TSA, 726 (40%) RSA, and 74 (4%) HA. The mean age was 67 years (SD 10), and 936 (52%) of the patients were female. RESULTS: The most common comorbidities were obesity (1,256, 69%) and hypertension (990, 55%). Patients with more comorbidities had lower ASES and SAS scores at baseline (p < 0.001). Elixhauser comorbidities continued to negatively impact ASES and SAS scores at one year (p = 0.002) and two-year follow-up (p = 0.002). Patients with more comorbidities reported greater pain interference on PROMIS at baseline (p = 0.007), but not at two years. Higher number of Charlson comorbidities were associated with lower scores on the SF-12 mental component at baseline (p < 0.001) and two years (p = 0.020). Higher number of Elixhauser comorbidities were associated with lower SF-12 physical component scores at baseline (p < 0.001) and two years (p = 0.004). CONCLUSION: Higher number of comorbidities was associated with lower baseline scores and worse outcomes on both shoulder-specific and general health PROMs. The presence of specific comorbidities may be used during shared decision-making to manage expectations for patients undergoing shoulder arthroplasty. Cite this article: Bone Joint J 2021;103-B(5):964-970.

Return to Sport After Bone-Patellar Tendon-Bone Autograft ACL Reconstruction in High School-Aged Athletes.

BACKGROUND: Anterior cruciate ligament (ACL) injuries are occurring with increasing frequency in the adolescent population. Outcomes after ACL reconstruction (ACLR) are inconsistently reported in homogeneous patient populations. PURPOSE/HYPOTHESIS: To evaluate outcomes after bone-patellar tendon-bone (BTB) autograft ACLR in competitive high school-aged athletes by examining return to sport (RTS), patient satisfaction, and reinjury rates. Our hypothesis was that RTS rates and satisfaction will be high and reinjury rates will be low. STUDY DESIGN: Case series; Level of evidence, 4. METHODS: An institutional ACL registry was utilized to identify competitive high school-aged athletes (14-18 years old) who underwent primary ACLR using BTB autograft with a minimum 2-year follow-up. A postoperative questionnaire was administered to determine rates and types of RTS, quality of sports performance, reinjury, and satisfaction. Uni- and multivariable analyses were used to identify demographic, sport-specific, and clinical factors related to RTS. RESULTS: A total of 53 patients were included (mean ± SD age at the time of surgery, 16.6 ± 1.34 years). Mean follow-up was 3.78 ± 0.70 years (range, 2.60-4.94 years). The overall ipsilateral ACL retear rate was 7.5% (n = 4). There were 10 subsequent ACL tears to the contralateral knee (19%). Forty-four (83%) patients successfully returned to at least their prior level of sport at a mean 10.5 ± 8.7 months (range, 3-48 months). Overall satisfaction was high, with 91% of patients very satisfied with the outcome. Higher confidence levels regarding performance of the reconstructed knee were associated with increased probability of RTS on multivariate analysis. CONCLUSION: BTB autograft ACLR results in high rates of RTS and satisfaction and low rates of subsequent ipsilateral ACL injuries in competitive high school-aged athletes. Patients with higher confidence in performance of the reconstructed knee are more likely to return to at least their prior level of sport.

Comparing Return to Sports After Patellofemoral and Knee Arthroplasty in an Age- and Sex-Matched Cohort.

BACKGROUND: Return to sports is an important outcome in ensuring patient satisfaction after knee-replacement surgery. However, few studies have directly compared unicompartmental knee arthroplasty (UKA), total knee arthroplasty (TKA), and patellofemoral arthroplasty (PFA). HYPOTHESIS: TKA will result in lower rates of return to sports than either UKA and PFA due to increased complexity and invasiveness. STUDY DESIGN: Cohort study; Level of evidence, 3. METHODS: Patients who underwent UKA, TKA, or PFA with 1 to 2 years of follow-up were sent a questionnaire regarding return to sports, satisfaction with return to sports, pain, the University of California, Los Angeles activity scale, and the High Activity Arthroplasty Score (HAAS). The patients who underwent either TKA or UKA were matched 2:1 with regard to age and sex to patients who underwent PFA. Differences were compared using analysis of variance, t tests, and chi-square tests. RESULTS: A total of 202 patients were eligible. After matching, the final cohort consisted of 23 PFA patients, 46 UKA patients, and 46 TKA patients. The majority of patients were female (87%), and the mean ± SD age was 56 ± 9.1 years. The UKA group had higher HAAS values than the TKA group pre- and postoperatively (9.9 vs 7.1 [P = .001] and 12.4 vs 9.5 [P < .001], respectively). Patients with UKA had higher rates of return to sports after surgery than those with TKA or PFA (UKA, 80.5%; TKA, 71.7%; PFA, 69.5%; P = 0.08). In addition, the UKA group had the highest satisfaction with this outcome. Improvement between pre- and postoperative scores was similar in all 3 groups. CONCLUSION: Patients who underwent UKA reported better activity scores and return-to-sports rates than patients who had TKA and PFA. No differences were found in improvement after surgery, suggesting that preoperative differences were reflected postoperatively. These findings inform shared decision making and can help to manage patient expectations after surgery.

beta2-Subunit-containing nicotinic acetylcholine receptors are involved in nicotine-induced increases in conditioned reinforcement but not progressive ratio responding for food in C57BL/6 mice.

RATIONALE: Nicotine administration potentiates conditioned reinforcement in rats, an effect that persists for weeks after chronic exposure. Little is known regarding the nicotinic receptor subtypes that may mediate this effect. OBJECTIVE: The purpose of this study was to determine whether beta2-subunit-containing nicotinic acetylcholine receptors (beta2*nAChRs) are necessary for lasting effects of nicotine on conditioned and primary reinforcement in mice. METHODS: Beta2 knockout (beta2KO) and wild-type (WT) mice received 14 days of nicotine exposure (NIC, 200 microg/ml in 2% saccharin) or saccharin alone (SAC) in their drinking water. Five days later, mice received paired presentations of a conditioned stimulus (CS) with water unconditioned stimulus (US) or explicitly unpaired presentations of the CS and US during Pavlovian discriminative approach training. Training was followed by two conditioned reinforcement tests. Mice were subsequently tested for food-reinforced responding in the absence of explicit cues followed by a progressive ratio test. RESULTS: During conditioned reinforcement testing, only mice in the paired condition showed increased responding in the CS-reinforced aperture over inactive apertures. WT-NIC mice showed enhanced conditioned reinforcement compared to WT-SAC animals. beta2KO-SAC mice showed elevated conditioned reinforcement compared to WT-SAC subjects, but beta2KO-NIC and beta2KO-SAC mice did not differ in responding with conditioned reinforcement. Prior nicotine exposure did not alter food-reinforced responding but resulted in elevated break points for food in both genotypes. CONCLUSION: These data show that nicotine exposure enhances conditioned reinforcement in mice and indicate that beta2*nAChRs are necessary for nicotine-dependent enhancement of incentive aspects of motivation but not motivation for primary reinforcement measured by progressive ratio responding.

Mixed inhibition of adenosine deaminase activity by 1,3-dinitrobenzene: a model for understanding cell-selective neurotoxicity in chemically-induced energy deprivation syndromes in brain.

Astrocytes are acutely sensitive to 1,3-dinitrobenzene (1,3-DNB) while adjacent neurons are relatively unaffected, consistent with other chemically-induced energy deprivation syndromes. Previous studies have investigated the role of astrocytes in protecting neurons from hypoxia and chemical injury via adenosine release. Adenosine is considered neuroprotective, but it is rapidly removed by extracellular deaminases such as adenosine deaminase (ADA). The present study tested the hypothesis that ADA is inhibited by 1,3-DNB as a substrate mimic, thereby preventing adenosine catabolism. ADA was inhibited by 1,3-DNB with an IC(50) of 284 µM, Hill slope, n = 4.8 ± 0.4. Native gel electrophoresis showed that 1,3-DNB did not denature ADA. Furthermore, adding Triton X-100 (0.01-0.05%, wt/vol), Nonidet P-40 (0.0015-0.0036%, wt/vol), or bovine serum albumin (0.05 mg/ml or changing [ADA] (0.2 and 2 nM) did not substantially alter the 1,3-DNB IC(50) value. Likewise, dynamic light scattering showed no particle formation over a (1,3-DNB) range of 149-1043 µM. Kinetics revealed mixed inhibition with 1,3-DNB binding to ADA (K(I) = 520 ± 100 µM, n = 1 ± 0.6) and the ADA-adenosine complex (K(IS) = 262 ± 7 µM, n = 6 ± 0.6, indicating positive cooperativity). In accord with the kinetics, docking predicted binding of 1,3-DNB to the active site and three peripheral sites. In addition, exposure of DI TNC-1 astrocytes to 10-500 µM 1,3-DNB produced concentration-dependent increases in extracellular adenosine at 24 h. Overall, the results demonstrate that 1,3-DNB is a mixed inhibitor of ADA and may thus lead to increases in extracellular adenosine. The finding may provide insights to guide future work on chemically-induced energy deprivation.