Understanding Patient Perspectives Regarding Remote Monitoring Devices Following Total Joint Replacement.

Background: Advances in smart technology have expanded into the field of orthopedic surgery to deliver enhanced patient care. Smart technology has also raised important issues regarding protected patient information. The purpose of this study is to determine patient preferences regarding smart technology in their postarthroplasty care. Methods: Patient surveys were administered in the office setting of 2 adult reconstructive orthopedic surgeons during a 4-week period. Surveys queried patient demographics, twelve yes/no questions, five continuous agree/disagree statements, and a single free-text question. Logistic regression and statistical significance testing were performed. Results: Of the study patients, 83.6% were willing to wear a device. Women were more likely to consent to a monitoring device and have activity data collected than men (P < .05). Younger patients were more likely to consent to a device and have data collected than octogenarians. Nearly 90% of respondents indicated peace of mind with data being constantly tracked. However, 64% of respondents had hesitations about a surgically implanted device that was independent of a previous arthroplasty surgery (P < .05). Conclusions: Patients are comfortable with smart technology being involved in their postoperative care, especially younger patients and women. Older individuals, possibly with less experience using smart technology in their lives, were not as willing to wear smart devices or have their data collected. Nearly two-thirds of patients had hesitations about surgically implanted smart devices. Further investigation is needed to understand hesitations concerning smart implants as the orthopedic community enters an era of commercially available smart implants in total joint arthroplasty.

Optimizing Total Knee Arthroplasty With ROSA® Robotic Technology.

A new robotic platform (ROSA® Knee system, Zimmer Biomet, Warsaw, Indiana) for total knee arthroplasty (TKA) has been created to increase precision of bony resections and knee balancing while maintaining surgeon autonomy. Our aim is to discuss: (1) the background of robotic technology in orthopedics, (2) current literature and potential benefits of the ROSA® Knee system, and the (3) optimal surgical technique for this specific robotic TKA platform. Early literature regarding this robotic system is promising as studies have shown precision of its bony resections, accuracy of overall limb alignment, and low early revision rates. There is a need for continued research on clinical outcomes using this platform, and the intention is to provide a review with insight into the potential advantages of robotics and the ideal surgical technique for successful use of this system.

The Effectiveness of Closed-Incision Negative-Pressure Therapy Versus Silver-Impregnated Dressings in Mitigating Surgical Site Complications in High-Risk Patients After Revision Knee Arthroplasty: The PROMISES Randomized Controlled Trial.

BACKGROUND: Revision total knee arthroplasty (rTKA) is associated with significant risk of wound-related morbidity. The present study aimed to evaluate the 1) efficacy of closed-incision negative-pressure therapy (ciNPT) vs silver-impregnated antimicrobial dressing (AMD) in mitigating postoperative surgical site complications (SSCs), 2) the effect of ciNPT vs AMD on certain postoperative health utilization parameters, and on 3) patient-reported outcomes (PROs) improvement at 90-day postoperative follow-up. METHODS: This multicenter randomized controlled trial was conducted between December 2017 and August 2019. Patients ≥22 years, at high risk for SSC, and receiving rTKA with full exchange and reimplantation of new prosthetic components or open reduction and internal fixation of periprosthetic fractures were screened for inclusion. Eligible patients were randomized to receive a commercially available ciNPT system or a silver-impregnated AMD (n = 147, each) for minimum of 5-day duration. Primary outcome was the 90-day incidence of SSCs with stratification in accordance with revision type (aseptic/septic). Secondary outcomes were the 90-day health care utilization parameters (readmission, reoperation, dressing changes, and visits) and PROs. RESULTS: Of 294 patients randomized (age: 64.9 ± 9.0 years, female: 59.6%), 242 (82.0%) patients completed the study (ciNPT: n = 124; AMD: n = 118). The incidence of 90-day SSCs was lower for the ciNPT cohort (ciNPT: 3.4% vs AMD: 14.3%; odds ratio (OR): 0.22, 95% confidence interval (0.08, 0.59); P = .0013). Readmission rates (3.4% vs 10.2%, OR: 0.30(0.11, 0.86); P = .0208) and mean dressing changes (1.1 ± 0.3 vs 1.3 ± 1.0; P = .0003) were lower with ciNPT. The differences in reoperation rates, number of visits, and PRO improvement between both arms were not statistically significant (P > .05). CONCLUSION: ciNPT is effective in reducing the 90-day postoperative SSCs, readmission, and number of dressing changes after rTKA. Recommending routine implementation would require true-cost analyses.

Rank-Based Similarity Search: Reducing the Dimensional Dependence.

This paper introduces a data structure for k-NN search, the Rank Cover Tree (RCT), whose pruning tests rely solely on the comparison of similarity values; other properties of the underlying space, such as the triangle inequality, are not employed. Objects are selected according to their ranks with respect to the query object, allowing much tighter control on the overall execution costs. A formal theoretical analysis shows that with very high probability, the RCT returns a correct query result in time that depends very competitively on a measure of the intrinsic dimensionality of the data set. The experimental results for the RCT show that non-metric pruning strategies for similarity search can be practical even when the representational dimension of the data is extremely high. They also show that the RCT is capable of meeting or exceeding the level of performance of state-of-the-art methods that make use of metric pruning or other selection tests involving numerical constraints on distance values.

Blood loss and transfusion rates following patellofemoral arthroplasty.

Patellofemoral arthroplasty (PFA) is a viable treatment option of the patient with isolated patellofemoral arthritis. Some of the purported advantages of PFA compared with total knee arthroplasty (TKA) include less invasive approach, less bone resection and tissue destruction, decreased operative time, shorter rehabilitation, better knee kinematics, and decreased blood loss. This study compared the blood loss associated with PFA with that of a cohort of patients with TKA. A proposed benefit of partial knee arthroplasty is less blood loss. Patellofemoral replacement seems not to have this benefit and blood loss prevention initiatives similar to those of TKA should be maintained.

Water-tight knee arthrotomy closure: comparison of a novel single bidirectional barbed self-retaining running suture versus conventional interrupted sutures.

Standard medial parapatellar arthrotomies of 10 cadaveric knees were closed with either conventional interrupted absorbable sutures (control group, mean of 19.4 sutures) or a single running knotless bidirectional barbed absorbable suture (experimental group). Water-tightness of the arthrotomy closure was compared by simulating a tense hemarthrosis and measuring arthrotomy leakage over 3 minutes. Mean total leakage was 356 mL and 89 mL in the control and experimental groups, respectively (p = 0.027). Using 8 of the 10 knees (4 closed with control sutures, 4 closed with an experimental suture), a tense hemarthrosis was again created, and iatrogenic suture rupture was performed: a proximal suture was cut at 1 minute; a distal suture was cut at 2 minutes. The impact of suture rupture was compared by measuring total arthrotomy leakage over 3 minutes. Mean total leakage was 601 mL and 174 mL in the control and experimental groups, respectively (p = 0.3). In summary, using a cadaveric model, arthrotomies closed with a single bidirectional barbed running suture were statistically significantly more water-tight than those closed using a standard interrupted technique. The sample size was insufficient to determine whether the two closure techniques differed in leakage volume after suture rupture.

Novel oscillatory mechanisms in the cholinergic control of Guinea pig sino-atrial node discharge.

UNLABELLED: Oscillatory Mechanisms in Sinus Node Cholinergic Control. INTRODUCTION: The role of the oscillatory after-potential V(os) and pre-potential ThV(os) in cholinergic control of discharge was studied in sino-atrial node (SAN). METHODS AND RESULTS: A microelectrode technique was used in isolated guinea-pig SAN superfused in vitro in high [K(+) ](o) to visualize V(os) and ThV(os) . The cholinergic agonist carbachol (CCh) decreased the amplitude and slope of V(os) and ThV(os) at a time when there was no increase in maximum diastolic potential. The slowing in SAN rate was due to slower and smaller ThV(os) that missed intermittently the threshold and occurred gradually later in diastole, but not to a decrease in the intrinsic rate of ThV(os) . Eventually, quiescence followed. Larger CCh concentrations quickly induced a hyperpolarization that altogether prevented the occurrence of oscillatory potentials. During CCh washout, ThV(os) reappeared and consistently reinitiated discharge. Lower [Ca(2+) ](o) also decreased slopes and amplitude of V(os) and ThV(os) , thereby slowing and stopping SAN discharge, as CCh did. Overdrive temporarily offset the negative chronotropic effects of CCh and of low [Ca(2+) ](o.) Cesium (a blocker of hyperpolarization-activated current I(f) ) did not abolish CCh inhibitory effects on oscillatory potentials. CONCLUSIONS: The cholinergic agonist CCh: (1) slows SAN discharge by decreasing the amplitude of V(os) and ThV(os) , but not the rate of ThV(os) ; (2) can cause hyperpolarization that altogether suppresses the oscillatory potentials; (3) is mimicked in its effects by low [Ca(2+) ](o) ; (4) is antagonized by procedures that increase cellular calcium; and (5) modifies the oscillatory potentials independently of I(f) .

Postoperative pain management.

Although the long-term results following traditional total joint arthroplasty are excellent, postoperative pain management has been suboptimal. Under-treatment of pain is a focus of growing concern to the orthopedic community. Poorly controlled postoperative pain leads to undesirable outcomes, including immobility, stiffness, myocardial ischemia, atelectasis, pneumonia, deep venous thrombosis, anxiety, depression, and chronic pain. Over the past decade, the attempt to minimize postoperative complications, combined with the move toward minimally invasive surgery and early postoperative mobilization, has made pain management a critical aspect of joint replacement surgery. Effective protocols are currently available; all include a multimodal approach. Debate continues regarding the ideal approach; however, reliance on narcotic analgesia alone is suboptimal.

Essential role of diastolic oscillatory potentials in adrenergic control of guinea pig sino-atrial node discharge.

BACKGROUND: The diastolic oscillatory after-potential Vos and pre-potential ThVos play an essential role in the pacemaker mechanism of sino-atrial node (SAN). The aim of this study was to investigate whether these oscillatory potentials are also involved in adrenergic control of SAN discharge. METHODS: Vos and ThVos were visualized by superfusing guinea pig SAN in high [K+]o. The actions of adrenergic agonists on oscillatory potentials were studied by means of a microelectrode technique. Statistical significance was determined by means of Student's paired t-test. RESULTS: In non-spontaneous SAN, norepinephrine (NE) decreased the resting potential into a voltage range ("oscillatory zone") where increasingly larger ThVos appeared and initiated spontaneous discharge. In slowly discharging SAN, NE gradually increased the rate by increasing the amplitude and slope of earlier-occurring ThVos and of Vos until these oscillations fused with initial diastolic depolarization (DD1). In the presence of NE, sudden fast rhythms were initiated by large Vos that entered a more negative oscillatory zone and initiated a large ThVos. Recovery from NE exposure involved the converse changes. The beta-adrenergic agonist isoproterenol had similar actions. Increasing calcium load by decreasing high [K+]o, by fast drive or by recovery in Tyrode solution led to growth of Vos and ThVos which abruptly fused when a fast sudden rhythm was induced. Low [Ca2+]o antagonized the adrenergic actions. Cesium (a blocker of If) induced spontaneous discharge in quiescent SAN through ThVos. In spontaneous SAN, Cs+increased Vos and ThVos, thereby increasing the rate. Cs+ did not hinder the positive chronotropic action of NE. Barium increased the rate, as Cs+ did. CONCLUSION: Adrenergic agonists: (i) initiate SAN discharge by decreasing the resting potential and inducing ThVos; (ii) gradually accelerate SAN rate by predominantly increasing size and slope of earlier and more negative ThVos; (iii) can induce sudden fast rhythms through the abrupt fusion of large Vos with large ThVos; (iv) increase Vos and ThVosby increasing cellular calcium; and (v) do not modify the oscillatory potentials by means of the hyperpolarization-activated current If. The results provide evidence for novel mechanisms by which the SAN dominant pacemaker activity is initiated and enhanced by adrenergic agonists.

Unanswered questions, unmet needs in venous thromboprophylaxis.

Although significant progress has been made over the past 25 years in preventing thromboembolic disease in patients undergoing total hip and total knee arthroplasty, important questions remain unanswered. Few would debate the need to seek a balance between maximal antithrombotic efficacy and minimal bleeding in choosing a thromboprophylactic strategy, but there is less agreement as to how efficacy should be defined, and whether efficacy and safety (however each is defined) are intrinsic to the thromboprophylactic agent chosen or depend as well on exogenous factors, ranging from the timing of drug administration to surgical technique. Differences between recent guidelines from the American Academy of Orthopaedic Surgeons (AAOS) and the American College of Chest Physicians (ACCP) illustrate these unanswered questions. The AAOS guidelines focus solely on preventing symptomatic pulmonary embolism and ignores the importance of other acute and chronic manifestations of venous thromboembolic disease. The ACCP, on the other hand, does consider these other manifestations of venous thromboembolic disease, and thus reaches very different conclusions about what constitutes effective thromboprophylaxis. Despite these questions and uncertainties, there are fundamental truths: (1) venous thromboembolism (VTE) is a known and serious complication of total joint arthroplasty, and (2) evidence-based thromboprophylaxis works. Gaps between guideline-recommended and actual orthopedic practice must be reduced.

Magnetic resonance imaging of acute "wiiitis" of the upper extremity.

We present the first reported case of acute "wiiitis", documented clinically and by imaging, of the upper extremity, caused by prolonged participation in a physically interactive virtual video-game. Unenhanced magnetic resonance imaging (MRI) demonstrated marked T2-weighted signal abnormality within several muscles of the shoulder and upper arm, without evidence of macroscopic partial- or full-thickness tearing of the muscle or of intramuscular hematoma.

On the mechanisms underlying diastolic voltage oscillations in the sinoatrial node.

AIM: The study of the mechanisms underlying the oscillatory afterpotential (V(os)) and prepotential (ThV(os)). BACKGROUND: It has been recently shown that V(os) and ThV(os) play an obligatory role in the dominant sinoatrial node (SAN) discharge. METHODS: Guinea pig isolated SAN was studied in vitro by means of a microelectrode technique. RESULTS: High [K(+)](o) and premature stimuli unmask V(os) superimposed on early diastolic depolarization and ThV(os) within a less negative voltage range ("oscillatory zone"). Subthreshold stimuli elicit ThV(os) in the oscillatory zone, but not at more negative values. Drive and caffeine shift the oscillatory zone in a negative direction. Low caffeine concentrations increase the size of V(os) and of ThV(os), rate, and force. High caffeine concentrations suppress V(os) but increase the size of ThV(os) and shift them to more negative values until they eventually miss the threshold. In quiescent SAN in high caffeine, a fast drive enhances ThV(os) size, thereby initiating a transient spontaneous rhythm ("overdrive excitation"). Adrenergic agonists potentiate caffeine-induced overdrive excitation through an increase in ThV(os). In high caffeine, the first twitch after quiescence is not larger, twitch relaxation is slower, V(os) is abolished, and the prolonged nonoscillatory afterdepolarization V(ex) is induced, consistent with an impairment of Ca2+ handling by the sarcoplasmic reticulum. The effects of caffeine in Tyrode's solution are accounted for by the caffeine-induced changes in the oscillatory potentials. Tetrodotoxin decreases force and size of both V(os) and ThV(os). CONCLUSIONS: The mechanism underlying V(os) is related to a diastolic release of Ca2+ from a Ca2+-overloaded sarcoplasmic reticulum, whereas that of ThV(os) appears to be related to ionic currents in the resting potential range that can initiate and sustain spontaneous discharge.

Obligatory role of diastolic voltage oscillations in sino-atrial node discharge.

The role of diastolic voltage oscillations in the initiation and maintenance of pacemaker discharge was studied in guinea pig-isolated sino-atrial (SA) node by means of a microelecrode technique. When [K(+)](o) is suitably increased, the maximum diastolic potential decreases and all action potentials (APs) assume the characteristics of dominant pacemakers (slow responses with U-shaped diastolic depolarization). Subsequently, as the slope and amplitude of diastolic depolarization (DD) decreases, the threshold is missed, unmasking the fused oscillatory potentials V(os) and ThV(os). As high [K(+)](o) perfusion continues, the oscillatory potentials become separated, V(os) following the AP and ThV(os) appearing later on, when DD enters a less negative voltage range (oscillatory zone). ThV(os) grow in amplitude and attain the threshold, thereby insuring a slow discharge. If [K(+)](o) is further increased, the smaller ThV(os) miss the threshold and SA node becomes quiescent. On reducing high [K(+)](o), ThV(os) re-appear, increase in size and initiate spontaneous discharge. As they occur progressively earlier during DD, ThV(os) eventually fuse with V(os): at that stage, DD appears to continue directly into the upstroke (U-shaped DD) and the oscillations are no longer seen. During recovery in Tyrode solution, size and slope of V(os) and of ThV(os) further increase and cause a faster discharge. When APs assume a subsidiary configuration, their DD (no longer U-shaped) abruptly terminates into the upstroke. In high [K(+)](o), increasing [Ca(2+)](o) or applying a fast drive increase the size and slope of V(os) and of ThV(os), which in turn restore or accelerate discharge. In contrast, low [Ca(2+)](o) abolishes V(os) and ThV(os) and causes SA node arrest. Low [Ni(2+)] (35.5 microM) increases the rate whereas high [Ni(2+)] (0.73 mM) stops the SA node. Ryanodine eliminates V(os) and ThV(os) and markedly slows or stops discharge. Thus, ThV(os) and V(os) are separate voltage oscillations that play an obligatory role in the initiation and maintenance of SA node discharge, V(os) by steepening early DD and ThV(os) by attaining the threshold in the dominant pacemaker range, either by gradually increasing during late DD at slow rates or by fusing with V(os) at fast rates. Both V(os) and ThV(os) are Ca(2+) dependent, but apparently in different ways.