Exploring the Feasibility and Usability of Smartphones for Monitoring Physical Activity in Orthopedic Patients: Prospective Observational Study.

BACKGROUND: Smartphones are often equipped with inertial sensors that measure individuals' physical activity (PA). However, their role in remote monitoring of the patients' PAs in telemedicine needs to be adequately explored. OBJECTIVE: This study aimed to explore the correlation between a participant's actual daily step counts and the daily step counts reported by their smartphone. In addition, we inquired about the usability of smartphones for collecting PA data. METHODS: This prospective observational study was conducted among patients undergoing lower limb orthopedic surgery and a group of nonpatients as control. The data from the patients were collected from 2 weeks before surgery until 4 weeks after the surgery, whereas the data collection period for the nonpatients was 2 weeks. The participant's daily step count was recorded by PA trackers worn 24/7. In addition, a smartphone app collected the number of daily steps registered by the participants' smartphones. We compared the cross-correlation between the daily steps time series obtained from the smartphones and PA trackers in different groups of participants. We also used mixed modeling to estimate the total number of steps, using smartphone step counts and the characteristics of the patients as independent variables. The System Usability Scale was used to evaluate the participants' experience with the smartphone app and the PA tracker. RESULTS: Overall, 1067 days of data were collected from 21 patients (n=11, 52% female patients) and 10 nonpatients (n=6, 60% female patients). The median cross-correlation coefficient on the same day was 0.70 (IQR 0.53-0.83). The correlation in the nonpatient group was slightly higher than that in the patient group (median 0.74, IQR 0.60-0.90 and median 0.69, IQR 0.52-0.81, respectively). The likelihood ratio tests on the models fitted by mixed effects methods demonstrated that the smartphone step count was positively correlated with the PA tracker's total number of steps (χ21=34.7, P<.001). In addition, the median usability score for the smartphone app was 78 (IQR 73-88) compared with median 73 (IQR 68-80) for the PA tracker. CONCLUSIONS: Considering the ubiquity, convenience, and practicality of smartphones, the high correlation between the smartphones and the total daily step count time series highlights the potential usefulness of smartphones in detecting changes in the number of steps in remote monitoring of a patient's PA.

The Use of Proximal Femur Replacement for the Management of Oncologic Lesions in the Proximal Femur: A Review.

With improved chemotherapeutic treatment, patients with primary or metastatic bone tumor have improved prognoses and longer life expectancies; therefore, durable limb-salvage constructs are critical. For tumors of the proximal femur, endoprosthetic replacement is an option for treatment in primary and metastatic disease, with the goals being tumor and pain control, earlier mobilization, shorter recovery period, and, in primary tumors, cure. This study provides a summary of current concepts in the treatment of oncologic lesions in the proximal femur with endoprostheses. Discussion of the inherent complications of these constructs is presented as well as the risks and treatment of reconstruction failure.

Remote optimization of an ultracold atoms experiment by experts and citizen scientists.

We introduce a remote interface to control and optimize the experimental production of Bose-Einstein condensates (BECs) and find improved solutions using two distinct implementations. First, a team of theoreticians used a remote version of their dressed chopped random basis optimization algorithm (RedCRAB), and second, a gamified interface allowed 600 citizen scientists from around the world to participate in real-time optimization. Quantitative studies of player search behavior demonstrated that they collectively engage in a combination of local and global searches. This form of multiagent adaptive search prevents premature convergence by the explorative behavior of low-performing players while high-performing players locally refine their solutions. In addition, many successful citizen science games have relied on a problem representation that directly engaged the visual or experiential intuition of the players. Here we demonstrate that citizen scientists can also be successful in an entirely abstract problem visualization. This is encouraging because a much wider range of challenges could potentially be opened to gamification in the future.

Distal Femoral Replacement for Acute Distal Femoral Fractures in Elderly Patients.

OBJECTIVES: To evaluate outcomes and complications using cemented modular distal femoral replacement in elderly patients with distal femoral fractures. DESIGN: Retrospective chart review, case series. SETTING: A Level 1 and Level 2 trauma center, both tertiary referral hospitals. PATIENTS/PARTICIPANTS: Eighteen patients older than 60 years (average age 77 years) who had cemented distal femoral replacement for distal femoral fractures (comminuted, intraarticular, osteoporotic, arthritic) between 2005 and 2013. Patients with previous knee surgery were excluded. INTERVENTION: Cemented modular distal femoral replacement. MAIN OUTCOME MEASURES: Implant status, complications, Knee Society Score, Musculoskeletal Tumor Society score, and Western Ontario and McMaster Osteoarthritis Index. RESULTS: All patients were extremely or very satisfied with their outcomes. For patients with functional outcome data, Knee Society Score averaged 85.7 with a functional score of 35, Musculoskeletal Tumor Society score averaged 19.2, and Western Ontario and McMaster Osteoarthritis Index score averaged 23.1 at an average follow-up of 2.3 years. Range of motion was 1-99 degrees. Implant-related complications occurred in 2 patients (11%); one required revision to total femoral replacement because of periprosthetic fracture and the other had a deep infection that required exchange of the components. No patient had aseptic loosening or patellar maltracking. There were no perioperative deaths or late amputations. CONCLUSIONS: Cemented modular distal femoral replacement is a viable treatment option in elderly patients that permits immediate full weight-bearing, with most patients returning to preoperative functional status. LEVEL OF EVIDENCE: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Reconstruction and control of a time-dependent two-electron wave packet.

The concerted motion of two or more bound electrons governs atomic and molecular non-equilibrium processes including chemical reactions, and hence there is much interest in developing a detailed understanding of such electron dynamics in the quantum regime. However, there is no exact solution for the quantum three-body problem, and as a result even the minimal system of two active electrons and a nucleus is analytically intractable. This makes experimental measurements of the dynamics of two bound and correlated electrons, as found in the helium atom, an attractive prospect. However, although the motion of single active electrons and holes has been observed with attosecond time resolution, comparable experiments on two-electron motion have so far remained out of reach. Here we show that a correlated two-electron wave packet can be reconstructed from a 1.2-femtosecond quantum beat among low-lying doubly excited states in helium. The beat appears in attosecond transient-absorption spectra measured with unprecedentedly high spectral resolution and in the presence of an intensity-tunable visible laser field. We tune the coupling between the two low-lying quantum states by adjusting the visible laser intensity, and use the Fano resonance as a phase-sensitive quantum interferometer to achieve coherent control of the two correlated electrons. Given the excellent agreement with large-scale quantum-mechanical calculations for the helium atom, we anticipate that multidimensional spectroscopy experiments of the type we report here will provide benchmark data for testing fundamental few-body quantum dynamics theory in more complex systems. They might also provide a route to the site-specific measurement and control of metastable electronic transition states that are at the heart of fundamental chemical reactions.

Blastomycosis: Case report of an isolated lesion in the distal fibula.

Blastomycosis (Blastomyces dermatitidis) is a fungal infection that occurs primarily in the lungs, but 15% to 60% of patients with systemic blastomycosis have skeletal involvement. Because the symptoms and radiographic appearance of bony lesions are variable, diagnosis and treatment may be delayed if fungal infections are not included in the differential diagnosis for a patient with a lytic bone lesion. We present the case of a man in his late 30s with no local or systemic signs of infection in whom biopsy-curettage of a painful ankle lesion identified budding yeast consistent with North American blastomycosis. After treatment with itraconazole, the patient was symptom-free and had returned to his previous activities without pain or difficulty.

High harmonic generation via continuum wave-packet interference.

High-order harmonic generation (HHG) is investigated theoretically in the over-the-barrier ionization regime revealing the strong signature of interference between two separately ionized and separately propagating free wave packets of a single electron. The interference leads to the emission of coherent light at a photon energy corresponding to the kinetic-energy difference of the two recolliding electron quantum paths, thus complementary to the well-known classical three-step picture of HHG. As will be shown by time-frequency analysis of the emitted radiation, the process entirely dominates the coherent HHG emission after the atomic ground state has been depleted by a strong field. Moreover, it can be isolated from the continuum-bound harmonics via phase matching.

Is humeral segmental defect replacement device a stronger construct than locked IM nailing?

Intramedullary (IM) nailing is currently the most common method for treating patients with impending pathologic humeral fractures; however, this treatment is associated with known complications primarily owing to violation of the rotator cuff during insertion. A better option is needed. To determine if a humeral segmental replacement prosthesis would provide a stronger construct compared with an IM nail in this setting, we compared the mechanical properties of these two devices in a cadaver model simulating an impending pathologic fracture. In each of nine matched pairs of fresh human humeri one was randomly selected to undergo a 50% lateral middiaphyseal defect simulating an impending pathologic fracture and subsequent fixation with an IM nail and bone cement. The contralateral humerus underwent fixation using a humeral segmental defect prosthesis. We determined T-scores using DEXA. Each specimen subsequently was tested in torsion to failure. Peak torque and peak rotation at failure were greater for the prosthesis specimens whereas torsional stiffness was greater for the IM nail specimens. We found a linear relationship between peak torque and T-score for each device with the slopes of the lines suggesting the construct with the prosthesis can withstand greater forces than the IM nail and the differences between devices were greater in weaker bones.

Argon beam coagulation as adjuvant treatment after curettage of aneurysmal bone cysts: a preliminary study.

UNLABELLED: The optimal treatment of aneurysmal bone cysts remains an area of debate. Curettage, with or without adjuvant therapy, has been advocated for tumors in most locations. To evaluate argon beam coagulation as adjuvant therapy to curettage, we retrospectively analyzed the complication and recurrence rates in 40 consecutive patients with a diagnosis of aneurysmal bone cyst. For our analysis of recurrence, we excluded six of the 40 patients who were lost to followup or had less than 18 months followup; five patients treated with resection also were excluded. Of the remaining 29 patients, 17 were treated with curettage and argon beam coagulation and 12 were treated with curettage with or without phenol. None of the 17 patients treated with curettage and argon beam coagulation had a recurrence, whereas four patients treated without argon beam coagulation had recurrences. There were no differences between patients treated with or without argon beam coagulation regarding frequencies of intraoperative complications, neurovascular injury, or bone graft incorporation. Argon beam coagulation seems to offer favorable control rates when compared with curettage with or without phenol. No complications have been experienced thus far with its use. LEVEL OF EVIDENCE: Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Low temperature 65Cu NMR spectroscopy of the Cu+ site in azurin.

(65)Cu central-transition NMR spectroscopy of the blue copper protein azurin in the reduced Cu(I) state, conducted at 18.8 T and 10 K, gave a strongly second order quadrupole perturbed spectrum, which yielded a (65)Cu quadrupole coupling constant of +/-71.2 +/- 1 MHz, corresponding to an electric field gradient of +/-1.49 atomic units at the copper site, and an asymmetry parameter of approximately 0.2. Quantum chemical calculations employing second order Møller-Plesset perturbation theory and large basis sets successfully reproduced these experimental results. Sensitivity and relaxation times were quite favorable, suggesting that NMR may be a useful probe of the electronic state of copper sites in proteins.

Histologic evaluation of the depth of necrosis produced by argon beam coagulation: implications for use as adjuvant treatment of bone tumors.

Argon beam coagulation (ABC) has been advocated as adjuvant treatment after curettage of aggressive benign bone tumors. This study was done to evaluate the depth of necrosis in cancellous bone treated with ABC. A 6-month-old pig was sacrificed and 20 1.5-cm cortical windows were created in the metaphyseal areas of the humeri, femora, and tibiae, exposing the underlying cancellous bone. The defects were randomly assigned to four groups: A, control; B, ABC at 50 W; C, 100 W; and D, 150 W. Histologic evaluation determined the depth of necrosis at each setting: A, 0.1 +/- 0.1 mm; B, 1.0 +/- 0.5 mm; C, 2.9 +/- 1.0 mm; and D, 4.2 +/- 0.7 mm. There were statistically significant differences between each of the experimental groups and the control (p < .0001), between groups B and C (p < .0001), and groups C and D (p = .0002).

Outpatient reduction mammaplasty: an eleven-year experience.

BACKGROUND: In the last 15 years, reduction mammaplasty has been increasingly performed on an outpatient basis. Despite this evolution, few outcome studies have been published regarding outpatient breast reduction surgery. OBJECTIVE: The authors documented clinical outcomes of reduction mammaplasty performed in an outpatient setting over an 11-year period and compared these results with published normative values in the plastic surgery literature. METHODS: A retrospective review was undertaken of 884 reduction mammaplasties in 444 patients at a single outpatient surgical center performed by the senior author (W.G.S.) from 1995 through 2006. In all cases, a laser-assisted, inferior pedicle, Wise pattern, reduction mammaplasty was performed. In addition to demographic and surgical data, complication frequency and type were recorded. Complication data were further stratified into minor and major categories. Potential minor complications included seroma, hematoma, soft tissue infection, dog-ears requiring revision, and small incisional breakdowns or delayed healing of less than 2 cm. Potential major complications included large incisional breakdowns or delayed healing of greater than 2 cm, nipple/areolar necrosis, need for blood transfusion, deep vein thrombosis, pulmonary embolus, myocardial infarction, and death. RESULTS: The mean patient age was 38 years (range, 16 to 73 years). Mean body-mass index was 27 (range 17 to 47). The reported preoperative brassiere cup sizes ranged from a 34 C to a 38 K, with a DD being the most common size. The mean preoperative sternal notch-to-nipple distance was 29 cm (range 22 to 54 cm). Forty patients smoked (9%). Mean clinical follow-up was 13 months. Mean total resection weight of breast tissue was 1228 g (range 100 to 5295 g). Mean operative time for reduction mammaplasty was 115 minutes (range 50 to 195 minutes). Nineteen percent of patients underwent multiple procedures, including abdominoplasty, lipoplasty, and facial procedures, with a mean operative time of 132 minutes (range 75 to 345 minutes). The overall complication rate was 14%, with 70 minor complications occurring in 62 patients. Specific minor complications included one seroma, four hematomas, eight soft tissue infections, two of which required a short course of intravenous antibiotics, one patient with dog-ears requiring surgical revision, and 56 small incisional wound breakdowns (< 2 cm). The small incisional breakdowns, which represented the largest group of complications, were further subdivided into 44 minor T-zone wounds, 3 nipple-areolar complex wounds, and 9 wounds of the vertical and horizontal incisions. Three major complications (0.67%) were recorded. Two patients had development of partial nipple/areolar necrosis. A third patient required anticoagulation for a pulmonary embolus diagnosed 10 days after surgery. Statistical analysis of the complication data revealed one significant relationship. Patients with a body mass index above the mean had a 21% complication rate as compared with a 12% rate for those below the mean. Of note, there was no increase in complication rate in the context of multiple procedures. CONCLUSIONS: This retrospective series is the largest to date involving outpatient reduction mammaplasty. Complication data derived from this series are comparable to previously published studies and thus support the safety and efficacy of outpatient reduction mammaplasty performed in an accredited facility.

Residue ionization in LpxC directly observed by 67Zn NMR spectroscopy.

The pH dependence of the solid-state (67)Zn NMR lineshapes has been measured for both the wild type (WT) and the H265A mutant of Aquifex aeolicus LpxC, each in the absence of substrate (resting state). The (67)Zn NMR spectrum of WT LpxC at pH 6 (prepared at 0 degrees C) contains two overlapping quadrupole lineshapes with C q values of 10 and 12.9 MHz, while the spectrum measured for the sample prepared at a pH near 9 (at 0 degrees C) is dominated by the appearance of a third species with a C q of 14.3 MHz. These findings are consistent with the two p K a values previously observed by the bell-shaped dependence of the LpxC-catalyzed reaction. On the basis of comparison of the experimental results with predictions from quantum mechanical/molecular mechanical (QM/MM) modeling, we suggest that p K a1 (low pH) represents the ionization of Glu78 and p K a2 (high pH) reflects the ionization of another active site residue located near the zinc ion, such as His265. These results are also consistent with water being bound to the Zn (2+) ion throughout this pH range. The (67)Zn NMR spectra of the H265A mutant appear to be pH independent, with a C q of 9.55 MHz being sufficient to describe both low- and high-pH data. The QM/MM models of the H265A mutant suggest that over this pH range water is bound to the zinc ion while Glu78 is protonated.

Progressive valgus deformity after curettage of benign lesions of the proximal tibia.

BACKGROUND: Progressive valgus deformity after proximal tibial metaphyseal fractures in pediatric patients has been well described, although the pathophysiology is not clear. We performed a retrospective study to evaluate the occurrence of progressive tibia valga after curettage of benign bone lesions of the tibia. METHODS: During a 6-year period, we performed curettage and bone grafting of benign bone lesions of the tibia in 20 patients aged 16 years and younger. Radiographs and clinical notes were reviewed. The diagnosis, age, sex, location of lesion, surgical approach, physeal arrest, limb-length discrepancy, deformity, and treatment were documented. RESULTS: Four patients subsequently developed progressive tibia valga (mean, 12 degrees; range, 7-21 degrees). Progressive valgus deformity occurred in 4 of 5 patients younger than 10 years old who had curettage of lesions of the proximal tibial metaphysis. Deformity did not occur in any of the 13 patients older than 10 years (range, 13-16 years) or in any of the 8 patients who had curettage of the distal tibia (age range, 6-14 years). In patients who developed tibia valga, the deformity progressed during the first 6 to 17 months postoperatively and then stabilized. One patient required corrective osteotomy at age 12 years for a symptomatic 21-degree deformity 3 years after curettage. The other 3 patients with tibia valga remained asymptomatic and demonstrated partial correction of their deformities, currently ranging from 3 to 7 degrees with a mean follow-up of 31 months (range, 19-47 months). CONCLUSIONS: Progressive tibia valga seem to be relatively common in patients younger than 10 years who have had curettage of the proximal tibial metaphysis. This potential sequela should be discussed thoroughly with the patient's parents before proceeding with surgery, and patients should be followed and evaluated for this postoperatively.

A QM/MM approach to interpreting 67Zn solid-state NMR data in zinc proteins.

We present here a (67)Zn solid-state NMR investigation of Zn(2+) substituted rubredoxin. The sample has been prepared as both a dry powder and a frozen solution to determine the effects of static disorder on the NMR line shape. Low-temperature experiments have been performed at multiple fields to determine the relative contributions to the NMR line shape from the electric field gradient and the anisotropic shielding tensors. Finally we present the theoretical interpretation of the experimental results utilizing a combined quantum mechanical molecular mechanics (QM/MM) approach. Theory predicts a sizable contribution from anisotropic shielding as compared with previously examined model systems. This is in good agreement with the experimental data.

Errors in the MRI evaluation of musculoskeletal tumors and tumorlike lesions.

Interpretation of an MRI of a suspected musculoskeletal neoplasm can be extremely difficult. Fifty-six MRIs originally evaluated by outside radiologists were independently evaluated by an expert panel consisting of three specialized musculoskeletal radiologists. The outside reports were then graded based upon accuracy and completeness of the differential diagnosis. We compared the expert opinions with those of the outside radiologists. According to the expert panel, only 30 of the 56 (54%) outside reports listed the most likely diagnosis as such and only 35 (63%) listed it at all. A complete appropriate differential diagnosis was listed in only 22 (39%) of the outside reports. Furthermore, 18 (32%) of the outside reports listed diagnoses judged to be extremely unlikely by the experts. In a subset of 15 patients with images that the expert panel had judged diagnostic of specific entities, only nine of the outside reports listed the correct diagnosis as such and only 10 listed it at all. Furthermore, 11 (73%) of the outside reports listed extremely unlikely possibilities for these diagnostic images. We found a substantial difference between the expert and the outside opinions.

Reconstruction of noncontained proximal tibial defects with divergent screws and cement.

Postoperative fracture is a well described complication following curettage and cementation of aggressive benign bone tumors. We asked whether: (1) the addition of diverging screws that engage the opposite cortex increase the strength and rigidity of the construct in the proximal tibia compared with (a) cement alone and (b) would cement with intramedullary Steinmann pins; and (2) the modes of failure be different for those constructs. The average load to failure for tibias reconstructed with cement augmented with diverging screws (6321 +/- 681 N) was higher than for tibias reconstructed with cement alone (2343 +/- 222 N). The average load to failure for tibias reconstructed with cement augmented with diverging screws (6885 +/- 445 N) was higher than for tibias reconstructed with cement and intramedullary Steinmann pins (5218 +/- 941 N). Furthermore, constructs with cement augmented with diverging screws were less likely to fail by an intraarticular fracture than other types of constructs. Our data support the use of diverging screws that engage the opposite cortex to augment the strength of the construct when using acrylic cement to fill noncontained defects after curettage of the proximal tibia. This more stable, stronger construct might allow earlier mobilization and rehabilitation after curettage, with a decreased risk of fracture.

Imaging of bone sarcomas.

Identification, staging, and treatment of bone sarcomas rely on both clinical and imaging evaluations. Although conventional radiography remains the primary imaging modality for characterizing bone tumors, bone scintigraphy, computed tomography, magnetic resonance imaging, and positron emission tomography can each add information for staging and treatment planning.