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Background: Recent work suggests that having aortic valve surgery in the morning increases risk for cardiac-related complications. This study therefore explored whether mortality and cardiac complications, specifically low cardiac output syndrome, differ for morning and afternoon cardiac surgeries.Methods: The study included adults who had aortic and/or mitral valve repair/replacement and/or coronary artery bypass grafting from 2011 to 2018. The components of the in-hospital composite outcome were in-hospital mortality and low cardiac output syndrome, defined by requirement for at least two inotropic agents at 24 to 48 h postoperatively or need for mechanical circulatory support. Patients who had aortic cross-clamping between 8 and 11 am (morning surgery) versus between 2 and 5 pm (afternoon surgery) were compared on the incidence of the composite outcome.Results: Among 9,734 qualifying operations, 0.4% (29 of 6,859) died after morning, and 0.7% (20 of 2,875) died after afternoon surgery. The composite of in-hospital mortality and low cardiac output syndrome occurred in 2.8% (195 of 6,859) of morning patients and 3.4% (97 of 2,875) of afternoon patients: morning versus afternoon confounder-adjusted odds ratio, 0.96 (95% CI, 0.75 to 1.24; P = 0.770). There was no evidence of interaction between morning versus afternoon and surgery type (P = 0.965), and operation time was statistically nonsignificant for surgery subgroups.Conclusions: Patients having aortic valve surgery, mitral valve surgery, and/or coronary artery bypass grafting with aortic cross-clamping in the morning and afternoon did not have significantly different outcomes. No evidence was found to suggest that morning or afternoon surgical timing alters postoperative risk.Editor’s Perspective: [ABSTRACT FROM AUTHOR]

Introduction: Despite knowledge of cardiorespiratory fitness (CRF) training responders and nonresponders, it is not well understood how the exercise intensity prescription affects the incidence of response. The purpose of this study was to determine CRF training responsiveness based on cohort-specific technical error after 12 wk of standardized or individually prescribed exercise and the use of a verification protocol to confirm maximal oxygen uptake (V˙O2max). Methods: Sedentary adult participants (9 men, 30 women; 48.2 ± 12.2 yr) completed exercise training on 3 d·wk−1 for 12 wk, with exercise intensity prescribed based on standardized methods using heart rate reserve or an individualized approach using ventilatory thresholds. A verification protocol was used at baseline and 12 wk to confirm the identification of a true V˙O2max and subsequent relative percent changes to quantify CRF training responsiveness. A cohort-specific technical error (4.7%) was used as a threshold to identify incidence of response. Results: Relative V˙O2max significantly increased (P < 0.05) from 24.3 ± 4.6 to 26.0 ± 4.2 and 29.2 ± 7.5 to 32.8 ± 8.6 mL·kg−1·min−1 for the standardized and individualized groups, respectively. Absolute V˙O2max significantly increased (P < 0.05) from 2.0 ± 0.6 to 2.2 ± 0.6 and 2.4 ± 0.8 to 2.6 ± 0.9 L·min−1 for the standardized and individualized groups, respectively. A significant difference in responsiveness was found between the individualized and standardized groups with 100% and 60% of participants categorized as responders, respectively. Conclusions: A threshold model for exercise intensity prescription had a greater effect on the incidence of CRF training response compared with a standardized approach using heart rate reserve. The use of thresholds for intensity markers accounts for individual metabolic characteristics and should be considered as a viable and practical method to prescribe exercise intensity. [ABSTRACT FROM AUTHOR]

The article offers information about respiratory compensation point (RCP) and deoxygenation break point (deoxy-BP) in Lactate Steady State. Topics discussed include separation of sustainable and nonsustainable exercise intensities; talks about association of RCP and deoxy-BP parameters with work and metabolic rates of human body; and focuses on mechanistic link between RCP and deoxy-BP.

Background: The elbow is highly susceptible to contracture, which affects up to 50% of patients who experience elbow trauma. Previously, we developed a rat model to study elbow contracture that exhibited features similar to the human condition, including persistently decreased ROM and increased capsule thickness/adhesions. However, elbow ROM was not quantitatively evaluated over time throughout contracture development and subsequent mobilization of the joint.Questions/purposes: The purposes of this study were (1) to quantify the time-dependent mechanics of contracture, including comparison of contracture after immobilization and free mobilization; and (2) to determine what changes occur in capsule and joint surface morphology that may support the altered joint mechanics.Methods: A total of 96 male Long-Evans rats were randomized into control and injury (unilateral soft tissue injury/immobilization) groups. Flexion-extension and pronation-supination joint mechanics (n = 8/group) were evaluated after 3, 7, 21, or 42 days of immobilization (IM) or after 42 days of IM with either 21 or 42 days of free mobilization (63 or 84 FM, respectively). After measuring joint mechanics, a subset of these limbs (n = 3/group) was prepared for histologic analysis and blinded sections were scored to evaluate capsule and joint surface morphology. Joint mechanics and capsule histology at 42 IM and 84 FM were reported previously but are included to demonstrate the full timeline of elbow contracture.Results: In flexion-extension, injured limb ROM was decreased compared with control (103° ± 11°) by 21 IM (70° ± 13°) (p = 0.001). Despite an increase in injured limb ROM from 42 IM (55° ± 14°) to 63 FM (83° ± 10°) (p < 0.001), injured limb ROM was still decreased compared with control (103° ± 11°) (p = 0.002). Interestingly, ROM recovery plateaued because there was no difference between injured limbs at 63 (83° ± 10°) and 84 FM (73° ± 19°) (p > 0.999). In pronation-supination, increased injured limb ROM occurred until 7 IM (202° ± 32°) compared with control (155° ± 22°) (p = 0.001), representative of joint instability. However, injured limb ROM decreased from 21 (182° ± 25°) to 42 IM (123° ± 47°) (p = 0.001), but was not different compared with control (155° ± 22°) (p = 0.108). Histologic evaluation showed morphologic changes in the anterior capsule (increased adhesions, myofibroblasts, thickness) and nonopposing joint surfaces (surface irregularities with tissue overgrowth, reduced matrix), but these changes did not increase with time.Conclusions: Overall, flexion-extension and pronation-supination exhibited distinct time-dependent patterns during contracture development and joint mobilization. Histologic evaluation showed tissue changes, but did not fully explain the patterns in contracture mechanics. Future work will use this rat model to evaluate the periarticular soft tissues of the elbow to isolate tissue-specific contributions to contracture to ultimately develop strategies for tissue-targeted treatments.Clinical Relevance: A rat model of posttraumatic elbow contracture quantitatively described contracture development/progression and reiterates the need for rehabilitation strategies that consider both flexion-extension and pronation-supination elbow motion. [ABSTRACT FROM AUTHOR]

Purpose: The purpose of this study was to investigate the role of the group III/IV muscle afferents in the bioenergetics of exercising skeletal muscle beyond constraining the magnitude of metabolic perturbation. Methods: Eight healthy men performed intermittent isometric knee-extensor exercise to task failure at ~58% maximal voluntary contraction under control conditions (CTRL) and with lumbar intrathecal fentanyl to attenuate group III/IV leg muscle afferents (FENT). Intramuscular concentrations of phosphocreatine (PCr), inorganic phosphate (Pi), diprotonated phosphate (H2PO4-), adenosine triphosphate (ATP), and pH were determined using phosphorous magnetic resonance spectroscopy (31P-MRS). Results: The magnitude of metabolic perturbation was significantly greater in FENT compared with CTRL for [Pi] (37.8 ± 16.8 vs 28.6 ± 8.6 mM), [H2PO4 - (24.3 ± 12.2 vs 17.9 ± 7.1 mM), and [ATP] (75.8% ± 17.5% vs 81.9% ± 15.8% of baseline), whereas there was no significant difference in [PCr] (4.5 ± 2.4 vs 4.4 ± 2.3 mM) or pH (6.51 ± 0.10 vs 6.54 ± 0.14). The rate of perturbation in [PCr], [Pi], [H2PO4 -, and pH was significantly faster in FENT compared with CTRL. Oxidative ATP synthesis was not significantly different between conditions. However, anaerobic ATP synthesis, through augmented creatine kinase and glycolysis reactions, was significantly greater in FENT than in CTRL, resulting in a significantly greater ATP cost of contraction (0.049 ± 0.016 vs 0.038 ± 0.010 mM⋅min-1⋅N-1). Conclusion: Group III/IV muscle afferents not only constrain the magnitude of perturbation in intramuscular Pi, H2PO4-, and ATP during small muscle mass exercise but also seem to play a role in maintaining efficient skeletal muscle contractile function in men. [ABSTRACT FROM AUTHOR]

Introduction: Common materials used for prosthetic liners and sockets have poor thermal properties, thus insulating the residual limb resulting in thermal discomfort and increased perspiration. The purpose of this work is to compare the temperature increase and amount of perspiration between traditional silicone liners and the SmartTemp liner, which incorporates phase change material to improve the thermal properties and mitigate perspiration. Materials and Methods: Sixteen individuals with transtibial amputations participated in a double-blind, randomized clinical trial. Participants were asked to cycle on a stationary bike for 25 minutes followed by a 10-minute rest period. This activity was completed once for each treatment with a 1-hour rest period between treatments. Temperature and perspiration data were collected as outcomes, and a paired 1-way Student t-test was used to compare the data. Results: The SmartTemp liner resulted in significantly reduced mean skin temperature and perspiration during the activity and postactivity periods when compared with the placebo liner. Conclusions: Use of the SmartTemp liner can positively impact the internal socket conditions. Reducing temperature and moisture within the socket can improve comfort and suspension, and reduce the risk of skin injury for persons with amputation who use a prosthesis. [ABSTRACT FROM AUTHOR]

Background: Although disturbed flow is thought to play a central role in the development of advanced coronary atherosclerotic plaques, no causal relationship has been established. We evaluated whether inducing disturbed flow would cause the development of advanced coronary plaques, including thin cap fibroatheroma.Methods and Results: D374Y-PCSK9 hypercholesterolemic minipigs (n=5) were instrumented with an intracoronary shear-modifying stent (SMS). Frequency-domain optical coherence tomography was obtained at baseline, immediately poststent, 19 weeks, and 34 weeks, and used to compute shear stress metrics of disturbed flow. At 34 weeks, plaque type was assessed within serially collected histological sections and coregistered to the distribution of each shear metric. The SMS caused a flow-limiting stenosis, and blood flow exiting the SMS caused regions of increased shear stress on the outer curvature and large regions of low and multidirectional shear stress on the inner curvature of the vessel. As a result, plaque burden was ≈3-fold higher downstream of the SMS than both upstream of the SMS and in the control artery (P<0.001). Advanced plaques were also primarily observed downstream of the SMS, in locations initially exposed to both low (P<0.002) and multidirectional (P<0.002) shear stress. Thin cap fibroatheroma regions demonstrated significantly lower shear stress that persisted over the duration of the study in comparison with other plaque types (P<0.005).Conclusions: These data support a causal role for lowered and multidirectional shear stress in the initiation of advanced coronary atherosclerotic plaques. Persistently lowered shear stress appears to be the principal flow disturbance needed for the formation of thin cap fibroatheroma. [ABSTRACT FROM AUTHOR]

PURPOSE:To compare the acute physiological responses of low-load resistance exercise (RE) with blood flow restriction (LL-BFR) to traditional high-load RE without BFR (HL-RE) in individuals with multiple sclerosis (MS). METHODS: Fifteen participants (men: n = 4; women: n = 11) with a confirmed diagnosis of relapsing-remitting MS randomly completed the following RE conditions: 1) LL-BFR, consisting of 4 sets (30-15-15-15) of bilateral leg press (LP) and knee extension (KE), at 20% of their 1RM, and with 50% of BFR and 2) HL-RE, consisting of 4 sets (10-10-10-10) of the same exercises at 70% of 1RM without BFR. There was a 1-min rest period between sets and 5 min between exercises. Lactate [La-] was measured at rest, 5 min post-, and 60 min post-exercise; muscle thickness (MT) for the 50% portion of the thigh was measured via ultrasound at rest, immediately post-, 30 min, and 60 min post-exercise; and the myoelectric activity of the vastus medialis (VM) and vastus lateralis (VL) muscles of both legs was measured using superficial electromyography (EMG) during each trial. Repeated measures analyses of variance with Bonferroni post hoc were used to detect significant differences between conditions within each time point. RESULTS: Although both trials significantly (p < 0.001) increased [La-] 5 min post-exercise, HL-RE resulted in significantly greater [La-] compared to LL-BFR (3.72 ± 1.41 vs. 2.20 ± 0.67 mmol/L, p < 0.001), however, both returned to resting levels 60 min post-exercise. There were no significant differences between HL-RE and LL-BFR for MT (cm) at any time point for either the right or left leg (p = 0.64 and p = 0.98). Additionally, MT was significantly (p ≤ 0.03) greater than resting (right: 3.43 ± 0.71, left: 3.43 ± 0.61) immediately post- (3.76 ± 0.68) and 30 min post-exercise (3.58 ± 0.73) for the right leg and immediately post (3.81 ± 0.66) for the left leg. HL-RE induced significantly (p < 0.001) greater EMG values than BFR-RE for the VM and VL muscles of both legs during the LP and KE exercises. CONCLUSIONS: HL-RE seems to induce greater acute physiological responses than BFR-RE for the measured parameters. Nonetheless, BFR-RE was well tolerated by the subjects and elicited significant increases in all the physiological parameters measured, which indicates that it may serve as a potential training strategy for MS patients. [ABSTRACT FROM AUTHOR]

Exposure to a microgravity environment decreases the maximal rate of O2 uptake (...O2max) in healthy individuals returning to a gravitational environment. The magnitude of this decrease in ...O2max is, in part, dependent on the duration of microgravity exposure, such that long exposure may result in up to a 38% decrease in ...O2max. This review identifies the components within the O2 transport pathway that determine the decrease in postmicrogravity ...O2max and highlights the potential contributing physiological mechanisms. A retrospective analysis revealed that the decline in ...O2max is initially mediated by a decrease in convective and diffusive O2 transport that occurs as the duration of microgravity exposure is extended. Mechanistically, the attenuation of O2 transport is the combined result of a deconditioning across multiple organ systems including decreases in total blood volume, red blood cell mass, cardiac function and mass, vascular function, skeletal muscle mass, and, potentially, capillary hemodynamics, which become evident during exercise upon re-exposure to the head-to-foot gravitational forces of upright posture on Earth. In summary, ...O2max is determined by the integration of central and peripheral O2 transport mechanisms, which, if not maintained during microgravity, will have a substantial long-term detrimental impact on space mission performance and astronaut health. [ABSTRACT FROM AUTHOR]

Background—Exercise oscillatory ventilation (EOV) is a noninvasive parameter that potently predicts outcomes in systolic heart failure (HF). However, mechanistic insights into EOV have been limited by the absence of studies relating EOV to invasive hemodynamic measurements and blood gases performed during exercise. Methods and Results—Fifty-six patients with systolic HF (mean±SEM age, 59±2 years; left ventricular ejection fraction, 30±1%) and 19 age-matched control subjects were studied with incremental cardiopulmonary exercise testing. Fick cardiac outputs, filling pressures, and arterial blood gases were measured at 1-minute intervals during exercise. We detected EOV in 45% of HF (HF+EOV) patients and in none of the control subjects. The HF+EOV group did not differ from the HF patients without EOV (HF-EOV) in age, sex, body mass index, left ventricular ejection fraction, or origin of HF. Univariate predictors of the presence of EOV in HF, among measurements performed during exercise, included higher right atrial pressure and pulmonary capillary wedge pressure and lower cardiac index (CI) but not Paco2 or Pao2. Multivariate logistic regression identified that low exercise CI is the strongest predictor of EOV (odds ratio, 1.39 for each 1.0-L · min-1 · m-2 decrement in CI; 95% confidence interval, 1.14-1.70; P=0.001). Among HF patients with EOV, exercise CI was inversely related to EOV cycle length (R=-0.71) and amplitude (R=-0.60; both P<0.001). In 11 HF+EOV subjects treated with 12 weeks of sildenafil, EOV cycle length and amplitude decreased proportionately to increases in CI. Conclusion—Exercise oscillatory ventilation is closely related to reduced CI and elevated filling pressures during exercise and may be an important surrogate for exercise-induced hemodynamic impairment in HF patients. [ABSTRACT FROM AUTHOR]

Background: Heterotopic ossification (HO) is a concern for patients undergoing hip surgery, especially surface replacement arthroplasty (SRA) who tend to be younger, more active, and anticipate good motion. It is unclear, however, whether HO occurs more frequently after SRA than traditional total hip arthroplasty (THA) and whether aspirin influences the risk. Questions/purposes: We therefore determined the incidence of HO after hip resurfacing compared with THA and determined whether aspirin influenced the incidence or severity of HO. Methods: Retrospectively we compared three patient cohorts: SRA with aspirin (176 hips; 160 patients), SRA with warfarin (60 hips; 57 patients), and THA with warfarin (240 hips; 222 patients). All patients satisfied the same selection criteria and all surgeries were performed through the posterolateral approach using spinal anesthesia. HO was classified using the technique of Brooker et al. comparing the preoperative, immediate postoperative, and 6- to 12-month followup radiographs (minimum, 1 year; mean, 2.7 years). Results: In the SRA with aspirin group, HO was detected in four of 151 hips (2.6%; two Grade I; one Grade II; one Grade III); in the SRA with warfarin group, eight of 46 hips (17.4%) had HO with four hips (8.7%) having severe HO (Grade III). All 12 patients with HO in both SRA groups were male. The HO incidence and severity was less for the SRA patients treated with aspirin compared with those treated with warfarin. In the THA with warfarin control group, HO was detected in five of 189 hips (2.6%; two Grade I; three Grade II). The HO incidence and severity were the same between the THA with warfarin and the SRA with aspirin cohorts. Conclusions: The risk of HO is greater in SRA than in THA in patients treated with warfarin postoperatively; aspirin appears to decrease the incidence and severity of HO after hip resurfacing surgery to a similar level as total hip arthroplasty. Level of Evidence: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Background: Osteolysis is a major mode of hip implant failure. Previous literature has focused on the amount of polyethylene wear comparing highly crosslinked polyethylene (HXPLE) with conventional liners but has not clarified the relative incidence of osteolysis with these two liners. Questions/purposes: We determined (1) the incidence of osteolysis in HXLPE versus conventional polyethylene (CPE), (2) the ability to detect and evaluate the size of lytic lesions using radiographs compared with CT scans, (3) head penetration in hips without and with lysis, and (4) determined whether acetabular position, head size, and UCLA activity score contributed to lysis. Methods: We compared head penetration and osteolysis on plain radiographs and presence and volume of osteolysis on CT scans in 48 patients with HXLPE (mean, 46.5 years) and 50 patients with CPE (mean, 43.2 years). The minimum followup was 5 years (average, 7.2 years; range, 5.1-10.9 years), Results: Osteolysis was apparent on CT in a larger number of patients with CPE liners than HXLPE liners: 12 of 50 (24%) versus one of 48 (2%), respectively. We found no correlation between head penetration and volume of osteolytic lesions. Head penetration was greater in patients with osteolysis. Smaller head sizes were associated with greater wear and those with osteolysis had smaller head sizes; however, there was no difference in acetabular component position or UCLA activity in those with lysis compared with those without. Conclusions: HXLPE diminished the incidence of osteolysis, but the lack of correlation between penetration and volume of osteolysis suggests other factors other than wear contribute to the development of osteolysis. Level of Evidence: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Few data exist identifying the influence of age on midthigh muscle composition. Further understanding how muscle composition of the midthigh changes with aging may improve current exercise prescriptions. PURPOSE: To examine the influence of chronological age on midthigh composition in 142 women (49.1±17.7 years, 164.5±7.1 cm, 66.6±10.7 kg). METHODS: Midthigh peripheral quantitative computed tomography scans were completed at the 40% site of the right femur and were analyzed using BoneJ software. Muscle density (MuD), cross-sectional area (mCSA), and intramuscular fat area (IMAT) were derived from the scans. One-way ANOVA compared group means by decade 20-29 (n=28), 30-39 (n=21), 40-49 (n=22), 50-59 (n=25), 60-69 (n=29), ≥70 years (n=17), while Dunnett's test performed post-hoc pairwise comparisons with the youngest group. Spearman's correlations examined each parameters association with age. A significance level of p<0.05 was selected a priori. RESULTS: MuD and mCSA displayed significant negative associations with age (r=-0.58 and r=-0.67, respectively, both p<0.01), while IMAT displayed a significant positive association with age (r=0.17, p=0.04). Group differences were observed for MuD (p<0.01), mCSA (p<0.01), IMAT (p=0.029). Dunnett's test revealed that MuD was significantly greater in the 20-29 years group compared to both age groups ≥60 years (81.5±1.2mg/cm³ vs 79.1±2.2mg/cm³ and 78.2±2.9mg/cm³, respectively; both p<0.01), and mCSA was significantly greater in the 20-29 years group compared to each age group ≥50 years (104.4±15.4cm² vs 85.9±14.3cm², 78.8±12.4cm², and 72.3±14.5cm², respectively, all p<0.01). IMAT was significantly greater in ≥70 years group compared to the 20-29 years group (6.23±2.3cm² vs 4.3±1.8cm², p=0.04). Interestingly, MuD, a surrogate for muscle quality, displayed smaller age-related decreases than mCSA (MuD: -3.9% vs mCSA: -29.7%) between the 20-29 and ≥70 years group. CONCLUSIONS: The current observations reveal that increased age displayed significant associations with midthigh muscle composition (MuD, mCSA, IMAT). However, future research is needed to identify which muscle composition parameter(s) contribute most effectively to maintaining muscle strength and physical performance with advanced age. [ABSTRACT FROM AUTHOR]

Background: L-2-hydroxyglutarate (L2HG) couples mitochondrial (Mito) and cytoplasmic energy metabolism in a model of cellular redox regulation. Under conditions of limited oxygen availability, mammalian cells generate L2HG to counteract the adverse effects of Mito reductive stress induced by hypoxia. L2HG is oxidized to α-ketoglutarate by L2HG dehydrogenase (L2HGDH) in a variety of mammalian tissues, including the heart. Myocardial ischemia/reperfusion injury (MIRI) is a consequence of coronary vascular disease and vascular procedures. Mito oxidative stress plays a critical role in MIRI. Here we hypothesized that L2HG protects against MIRI. Methods and Results: We induced accumulation of L2HG by heterozygous (HET) and homozygous (KO) deletion of L2HGDH gene in mice. The hearts isolated from HET, KO, and wild-type (WT) littermate mice were subjected to 30 min global thermal ischemia followed by 60 min reperfusion. Cardiac function and energy metabolism were simultaneously measured using a Langendorff heart perfusion model and 31P-NMR spectroscopy. We found that female HET and KO exhibited better recovery of cardiac function post-MIRI in consistent with better preservation of intracellular ATP and phosphocreatine (Table). Using HPLC, we measured compounds representative of cellular redox state (GSG, GSSG, NAD, NADH, NADP, NADPH, coenzyme A and ascorbate), cellular energy state (ATP, ADP, AMP, GTP, GDP, GMP, UTP, UDP, UMP, CTP, CDP, CMP, IMP, malonyl-CoA and acetyl-CoA), and nucleotide catabolism (adenosine, hypoxanthine, xanthine and inosine) in freeze-clamped hearts. We found that ratios of GSH/GSSG and ATP/ADP increased in HET and KO hearts (Table). Interestingly, the ratios of NADH/NAD and NADPH/NADP increased only in KO but not in HET hearts. Consistent with the increased ratio of ATP/AMP, hypoxanthine and xanthine decreased only in KO hearts but not in HET hearts (Table). Conclusion: The accumulation of L2HG in a genetic mouse model protects against MIRI though increasing cellular antioxidative capacity and preserving high energy phosphates. The underlying mechanism of these beneficial adaptive phenomena warrants further study. Targeting L2HG levels and L2HGDH expression may serve as new therapeutic strategies for MIRI protection. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Exercise intensity thresholds: identifying the boundaries of sustainable performance" is presented.

Purpose: The purpose was to evaluate tandem gait (TG), Balance Error Scoring System (BESS), and modified Balance Error Scoring System (mBESS) performance acutely after concussion in collegiate student-athletes. In addition, we sought to evaluate the psychometric properties of TG, including minimal detectable change (MDC), sensitivity, and specificity. Methods: Seventy-six National Collegiate Athletic Association student-athletes performed TG and BESS tests: 38 acutely after concussion and 38 controls. Participants were tested at baseline (time 1) and again acutely after concussion, or the following year for controls (time 2). Ten controls, tested simultaneously by two researchers, established a TG interrater minimal detectable change. A 2 × 2 mixed-design ANOVA compared each outcome variable. An receiver operating characteristic curve analysis was used to evaluate sensitivity, specificity, and area under the curve (AUC). Result: There was a significant interaction (F = 8.757, P = 0.004) for TG whereby the concussion group was slower after concussion (10.59 ± 1.53 vs 11.80 ± 2.67 s), whereas there was no difference for controls (10.13 ± 1.72 vs 9.93 ± 1.85 s). There was no significant interaction for BESS (F = 0.235, P = 0.630) or mBESS (F = 0.007, P = 0.935). TG had a sensitivity of 0.632, a specificity of 0.605, and an AUC of 0.704. BESS had a sensitivity of 0.447, a specificity of 0.500, and an AUC of 0.508. mBESS had a sensitivity of 0.474, a specificity of 0.632, and an AUC of 0.535. Conclusions: Participants completed TG significantly slower after concussion, whereas no change across time was detected for controls. In contrast, BESS and mBESS performances were similar at both testing times in both groups. Our AUC analysis was acceptable for TG, but a failure for both BESS and mBESS; thus, TG may be a useful alternative for clinicians conducting postconcussion postural control assessments. [ABSTRACT FROM AUTHOR]

Background: Prior investigations have recognized the presence of patient-perceived noise generation after total knee arthroplasty (TKA). However, questions remain regarding its overall frequency after both TKA and unicompartmental knee arthroplasty (UKA) as well as with respect to its association with demographic and prosthesis-related factors and its association with patient-reported outcomes.Questions/purposes: The purposes of this study were (1) to determine the frequency with which patients report noise coming from the knee after TKA or UKA; (2) to identify patient and prosthesis-related factors associated with noise generation; and (3) to ascertain whether noise coming from the knee is associated with residual symptoms after knee arthroplasty.Methods: A five-center survey study was designed to identify patient-perceived noise and to quantify the degree of residual symptoms and functional deficits in patients after TKA or UKA. Data were collected by an independent, third-party survey center, which administered questions about residual symptoms, function, and pre- and postoperative activity levels. Patients meeting prespecified inclusion criteria were specifically questioned regarding perceived noises from their knee within the last 30 days; those who reported hearing noises sometimes, often, or extremely often were categorized as positive. We retrospectively identified 2671 patients who underwent TKA and 744 patients who underwent UKA and who met inclusion criteria; the final survey population included 1580 patients who underwent TKA and 476 patients who underwent UKA (68% response rate). TKA implant types included cruciate-retaining (59%), posterior-stabilized (16%), rotating-platform (13%), gender-specific (7%), and high-flex (5%). Differences in baseline demographic variables were accounted for using multiple logistic regression statistical analyses. Chi square analyses were used to compare the frequency of residual symptoms in those patients with and without noise generation.Results: Overall, 27% (557 of 2056; 95% confidence interval [CI], 25-29) of all patients undergoing knee arthroplasty reported hearing grinding, popping, or clicking from their operative knee in the last 30 days. Men (odds ratio [OR], 1.3; 95% CI, 1.0-1.6; p = 0.02) and younger patients (χ2 [df = 7] = 67.3; p < 0.001) were more likely to report noise generation. After controlling for potential confounding variables, noise generation was more common after TKA (29%) than UKA (21%; OR, 1.5; 95% CI, 1.2-2.0; p < 0.001). Among TKA designs, the likelihood of noise generation was greater in posterior-stabilized (41%; OR, 2.5; 95% CI, 1.8-3.7; p < 0.001), rotating-platform (45%; OR, 2.8; 95% CI, 1.9-4.2; p < 0.001), and gender-specific (36%; OR, 2.0; 95% CI, 1.2-3.2; p = 0.007) designs than in cruciate-retaining (23%) knees. Patient-perceived noise generation was associated with residual symptoms, including difficulty getting in and out of a chair (38% versus 25%, p < 0.001), limp (39% versus 25%, p < 0.001), swelling (42% versus 24%, p < 0.001), and stiffness (40% versus 23%, p < 0.001) compared with those who did not report noise generation after TKA.Conclusions: Patients frequently perceive noises coming from the knee after arthroplasty, more so in TKA than UKA. Patients reporting noises from the knee were more likely to report functional limitations and the presence of a limp, swelling, and stiffness. Surgeons should inform patients preoperatively of this possibility, because unmet patient expectations are known to negatively impact patient satisfaction after surgery. Subsequent investigations should focus on determining if there is a causal relationship between noise generation and residual symptoms after knee arthroplasty.Level Of Evidence: Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

Background: Patient-perceived noise from prostheses after total hip arthroplasty (THA) does occur, yet questions remain including the overall frequency of this finding, demographic and prosthesis-related factors, and the association of noise generation with patient-reported outcomes.Questions/purposes: The purposes of this study were (1) to determine the frequency with which patients report noise coming from the hip after THA; (2) to identify patient and prosthesis-related factors associated with noise generation; and (3) to ascertain if noise generation is associated with pain or functional impairment after THA.Methods: A five-center study was designed to quantify the degree of residual symptoms and functional deficits in patients undergoing THA. Three centers were academic practices, whereas two centers were private practices that provided training programs for orthopaedic residents and fellows. Each contributing surgeon was fellowship-trained and specialized in joint replacement. Inclusion criteria for this study were (1) men between 18 and 60 years old and women between 18 and 55 years old; (2) patients requiring primary hip surgery as a result of noninflammatory arthritis such as osteoarthritis, traumatic arthritis, or avascular necrosis; (3) a UCLA activity score of 6 or more before they were limited by pain; and (4) patients who had undergone a primary THA within 1 to 4 years before the start of the study and had a minimum of 1 year of clinical followup. Attempts were made to contact all identified patients meeting these inclusion criteria. Data were collected by an independent, third-party survey center blinded to the implant design and bearing surface used who administered questionnaires about residual symptoms, function, and pre- and postoperative activity levels using previously published survey instruments. Patients were specifically queried regarding perceived noise from their THA. We retrospectively identified 1242 eligible patients. Of the 1242 patients, 105 were found to have exclusions during the screening section of the questionnaire: postoperative infection (six THAs), fracture (two), dislocation (seven), or revision (17); limited activity level because of an operation on the opposite hip (34); and premorbid UCLA score of less than 6 (39). In addition, 128 individuals refused to participate, 156 were never available, 108 were not found as a result of a bad address/phone number, 48 were contacted but did not complete the interview, nine had died, and six had a language barrier. This left 682 of the 1137 eligible patients with completed surveys (60% response rate). The mean age was 50 ± 8 years at the time of surgery with 63% being men, and they were contacted at a mean of 3 ± 1 years postoperatively. Bearing surfaces (femoral head-acetabular liner) included 210 (31%) metal-on-metal, 144 (21%) ceramic-on-ceramic, 142 (21%) ceramic-on-polyethylene, 141 (21%) cobalt-chromium-on-polyethylene, and 44 (6%) oxidized zirconium-on-polyethylene. Differences in baseline demographic variables were accounted for using multiple logistic regression statistical analyses. Pearson's correlation coefficients were used to determine the association of noise generation with residual symptoms.Results: Overall, 9% (61 of 682; 95% confidence interval [CI], 7-11) of young patients undergoing primary THA reported noise generation. Females (12% [30 of 251 patients]) were noted to have an increased likelihood of reporting noise versus males (7% [30 of 431 patients]; odds ratio, 1.8; 95% CI, 1.1-3.1; p = 0.03). After controlling for potential confounding variables including female sex and length of followup, patients receiving a ceramic-on-ceramic or metal-on-metal bearing surface (14% [50 of 355]) reported an increased frequency of grinding, popping, and clicking in the 30 days before survey administration versus those receiving a polyethylene liner with a ceramic, oxidized zirconium, or cobalt-chromium femoral head (3% [10 of 327 patients]; odds ratio, 5.6; 95% CI, 2.7-11.5; p < 0.001). Noise generation was associated with increased pain (r = 0.23, p < 0.001) and stiffness (r = 0.22, p < 0.001) after THA.Conclusions: When interviewed by an independent third party, patients receiving a metal-on-metal or ceramic-on-ceramic bearing reported a higher frequency of noise generation versus patients receiving a polyethylene liner after THA. Young patients undergoing THA should be counseled that noise generation could be associated with increased pain after THA.Level Of Evidence: Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

Background: Custom cutting guides (CCGs; sometimes called patient-specific instrumentation [PSI]) in total knee arthroplasty (TKA) use preoperative three-dimensional imaging to fabricate cutting blocks specific to a patient's native anatomy.Questions/purposes: The purposes of this study were to determine if CCGs (1) improve clinical outcomes as measured by UCLA activity, SF-12, and Oxford knee scores; and (2) coronal mechanical alignment versus standard alignment guides.Methods: This was a retrospective cohort study of patients undergoing primary TKA using the same cruciate-retaining, cemented TKA system between January 2009 and April 2012. Patients were included if they were candidates for a unilateral, cruciate-retaining TKA and met other prespecified criteria; patients were allowed to self-select either an MRI-based CCG procedure or standard TKA. Ninety-seven of 120 (80.8%) patients in the standard and 104 of 124 (83.9%, p = 0.5) in the CCG cohort with a minimum of 1-year followup were available for analysis. The first 95 patients in the standard (mean followup, 3 years; range, 1-4 years) and CCG (mean followup, 2 years; range, 1-4 years) cohorts were compared. The alignment goal for all TKAs was a hip-knee-ankle (HKA) angle of 0°. UCLA, SF-12, and Oxford knee scores were collected preoperatively and at each patient's most recent followup visit. Postoperative, rotationally controlled coronal scout CT scans were used to measure HKA alignment. Independent-sample t-tests and chi-square tests were used for comparisons with a p value ≤ 0.05 considered significant.Results: At the most recent followup, no differences were present between the two cohorts for range of motion (114° ± 14° in CCG versus 115° ± 15° in standard, p = 0.7), UCLA (6 ± 2 in CCG versus 6 ± 2 in standard, p = 0.7), SF-12 physical (44 ± 12 in CCG versus 41 ± 12 in standard, p = 0.07), or Oxford knee scores (39 ± 9 in CCG versus 37 ± 10 in standard, p = 0.1). No differences were present for the incremental improvement in the UCLA (1 ± 4 in CCG versus 1 ± 3 in standard, p = 0.5), SF-12 physical (12 ± 20 in CCG versus 11 ± 21, p = 0.8), or Oxford knee scores (16 ± 9 in CCG versus 19 ± 10 in standard, p = 0.1) from preoperatively to postoperatively. There was no difference in the percentage of outliers for alignment (23% in standard versus 31% in CCG with HKA outside of 0° ± 3°; p = 0.2) between the two cohorts.Conclusions: At a mean followup of greater than 2 years, CCGs fail to demonstrate any advantages in validated knee outcome measure scores or coronal alignment as measured by CT scan versus the use of standard instrumentation in TKA. The clinical benefit of CCGs must be proven before continued implementation of this technology.Level Of Evidence: Level III, retrospective controlled study. [ABSTRACT FROM AUTHOR]

The activPAL is an accelerometer-based monitor worn on the thigh that classifies daily activities into three categories (sitting/lying down, standing, and stepping). The monitor discriminates between sitting/lying and the upright position by detecting the inclination of the thigh. It detects stepping from the acceleration versus time wave form. However, a current limitation of the activPAL is that it does not discriminate between sitting and lying down. Purpose: This study aimed to determine whether placing a second activPAL monitor on the torso would allow the detection of seated versus lying postures. Methods: Fifteen healthy adults (18-55 yr of age) wore an activPAL on the right thigh and another activPAL over the right rib cage. Both monitors were synchronized and initialized to record data in 15-s epochs. Participants performed a semistructured routine of activities for 3 min each. Activities included lying down (while supine, prone, and on the side), sitting, standing, sweeping, treadmill walking at 3 mph, and treadmill running at 6 mph. The spatial orientation of the thigh and chest monitors was used to determine body posture, and the activPAL on the thigh was used to detect ambulation. Results: The use of two activPAL devices enabled four behaviors to be accurately classified. The percentages of observations that were classified accurately were as follows: lying down (100%), sitting (100%), standing/light activity in the upright position (90.8%), and stepping (100%). Conclusions: The current method allows researchers to obtain more detailed information on postural allocation compared with that in the use of a single activPAL on the thigh. [ABSTRACT FROM AUTHOR]

Background: Potential advantages suggested but not confirmed for surface replacement arthroplasty (SRA) over THA include lower frequency of limp, less thigh pain, less limb length discrepancy, and higher activity. Questions/purposes: We therefore determined whether patients having SRA had a limp, thigh pain, or limb length discrepancy less frequently or had activity levels higher than patients having THA. Methods: In a multicenter study, we surveyed 806 patients aged 18 to 60 years with a premorbid UCLA activity score of 6 or more who underwent hip arthroplasty for noninflammatory arthritis at one of five orthopaedic centers. Patients had either a cementless THA with an advanced bearing surface (n = 682) or an SRA (n = 124). The patients were demographically comparable. Specific telephone survey instruments were designed to assess limp, thigh pain, perception of limb length, and activity levels. Minimum followup was 1 year (mean, 2.3 years; range, 1.1–3.9 years). Results: When controlled for age, sex, and premorbid activity level, patients with SRA had a higher incidence of complete absence of any limp, lower incidence of thigh pain, lower incidence of perception of limb length discrepancy, greater ability to walk continuously for more than 60 minutes, higher percentage of patients who ran after surgery, greater distance run, and higher percentage of patients who returned to their most favored recreational activity. Conclusions: When interviewed by an independent third party, patients with SRA reported higher levels of function with fewer symptoms and less perception of limb length discrepancy compared to a similar cohort of young, active patients with THA. Level of Evidence: Level III, therapeutic study. See Instructions for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]

Periacetabular osteotomy (PAO) is an effective acetabular reorientation technique for treatment of symptomatic acetabular dysplasia. In hips with severe deformities, an adjunctive femoral osteotomy (PFO) may optimize correction, joint stability, and congruency. We analyzed the clinical and radiographic results of combined PAO/PFO in treating severe hip deformities. Second, we compared the clinical results of patients treated with PAO/PFO with patients treated with isolated PAO for lesser deformities. Twenty-five patients (28 hips) treated with PAO/PFO were reviewed and followed a minimum of 16 months (mean, 44 months). The matched PAO cohort included 25 patients (28 hips). For the PAO/PFO group, the average Harris hip score improved from 60.9 to 86.3. Eighty-nine percent of the patients demonstrated at least a 10-point improvement in the hip score and 75% had a Harris hip score over 80 points. Radiographic evaluation demonstrated consistent deformity correction. The PAO/PFO group had a lower average Harris hip score preoperatively, yet hip function after surgery was comparable between groups. These data indicate combined PAO/PFO is associated with improved hip function in most patients. These clinical results are comparable to those obtained with isolated PAO for lesser hip deformities. [ABSTRACT FROM AUTHOR]

Unlabelled: There are a number of options available to manage the patella when revising a failed total knee arthroplasty. If the previous patellar component is well-fixed, undamaged, not worn, and compatible with the femoral revision component, then it can be retained. When a patellar component necessitates revision and is removed with adequate remaining patellar bone stock, an onlay-type all-polyethylene cemented implant can be used. Management of the patella with severe bony deficiency remains controversial. Treatment options for the severely deficient patella include the use of a cemented all-polyethylene biconvex patellar prosthesis, patellar bone grafting and augmentation, patellar resection arthroplasty (patelloplasty), performing a gull-wing osteotomy, patellectomy, or the use of newer technology such as a tantalum (trabecular metal) patellar prosthesis. Severe patellar bone deficiency is a challenging situation because restoration of the extensor mechanism, proper patellar tracking, and satisfactory anatomic relationships with the femoral and tibial components are critical for an optimal clinical outcome.Level Of Evidence: Level IV, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence. [ABSTRACT FROM AUTHOR]