Midterm outcomes of total hip arthroplasty after internal hemipelvectomy and iliofemoral arthrodesis.

BACKGROUND AND OBJECTIVES: Recent studies have reported acceptable outcomes after arthrodesis takedown and conversion to total hip arthroplasty (THA); however, there are no reports on outcomes after oncologic resection, which are inherently complex and may portend poorer outcomes. The purpose of this study was to examine the surgical and functional outcomes of patients who underwent prior hemipelvectomy for tumor resection and were later converted to THA. METHODS: All patients who had prior iliofemoral arthrodesis after oncologic resection that were later converted to THA at a single institution were examined. Charts were reviewed for demographic information, operative information, functional outcomes, and complications/reoperations. RESULTS: All three patients in this study were males who underwent internal hemipelvectomies for chondrosarcoma. Patients were converted to THA at a mean of 26 years after arthrodesis. Mean follow-up after conversion to THA was 7.4 years. During this follow-up period, two of the three patients required revision surgery. At last follow-up, the mean Harris Hip Score was 81 and the mean Mayo Hip Score was 67, and all patients were ambulatory without significant pain. CONCLUSIONS: Overall, patients who undergo iliofemoral arthrodesis after oncologic hemipelvectomy and are later converted to THA can expect to have a reasonable outcome, despite a high rate of complications and revision surgery.

Can the ACS-NSQIP surgical risk calculator predict postoperative complications in patients undergoing sacral tumor resection for chordoma?

BACKGROUND AND OBJECTIVES: The ACS-NSQIP surgical risk calculator is an online tool that estimates the risk of postoperative complications. Sacrectomies for chordoma are associated with a high rate of complications. This study was to determine if the ACS-NSQIP calculator can predict postoperative complications following sacrectomy. METHODS: Sixty-five (42 male, 23 female) patients who underwent sacrectomy were analyzed using the Current Procedural Terminology (CPT) codes: 49215 (excision of presacral/sacral tumor), 63001 (laminectomy of sacral vertebrae), 63728 (laminectomy for biopsy/excision of sacral neoplasm) and 63307 (sacral vertebral corpectomy for intraspinal lesion). The predicted rates of complications were compared to the observed rates. RESULTS: Complications were noted in 44 (68%) patients. Of the risk factors available to input to the ACS-NSQIP calculator, tobacco use (OR, 20.4; P < .001) was predictive of complications. The predicted risk of complications based off the CPT codes were: 49215 (16%); 63011 (6%); 63278 (11%) and 63307 (15%). Based on ROC curves, the use of the ACS-NSQIP score were poor predictors of complications (49215, AUC 0.65); (63011, AUC 0.66); (63307, AUC 0.67); (63278, AUC 0.64). CONCLUSION: The ACS-NSQIP calculator was a poor predictor of complications and was marginally better than a coin flip in its ability to predict complications following sacrectomy for chordoma.

Advancing patient age is associated with worse outcomes in low- and intermediate-grade primary chondrosarcoma of the pelvis.

BACKGROUND: Conventional primary pelvic chondrosarcoma often presents as a low- or intermediate-grade tumor in older patients. Although this is the most common variant of pelvic chondrosarcoma, studies examining treatment outcomes are lacking. The purpose of this study was to evaluate patients with these tumors to determine their outcomes of treatment. METHODS: Seventy-three patients (grade I [n = 19, 26%] and grade II [n = 54, 74%]) were reviewed including 55 (75%) males and 18 (25%) females, with a mean age of 51 (range, 17-81) years and follow-up of 9 ± 5 years. RESULTS: The 10-year disease-specific survival was 71%. Grade II disease (hazard ratio [HR], 6.74; P = .04) and age ≥50 years (HR, 3.97; P = .02) was associated with death due to disease. The 10-year local recurrence- and metastatic-free survival were 79% and 72%. Of the patients with a local recurrence (n = 11), 7 (64%) recurred at a higher histological grade. Patient age ≥50 years was associated with local recurrence (HR, 10.03; P = .02) and metastatic disease (HR, 4.20; P = .02). CONCLUSION: Advancing patient age was an independent risk factor for worse survival and disease recurrence. Tumors often recurred locally at a higher grade and as such wide local excision remains the treatment of choice for these tumors.

Association between patient age and the risk of mortality following local recurrence of a sacral chordoma.

BACKGROUND: Local recurrence (LR) of sacral chordoma is a difficult problem and the mortality risk associated with LR remains poorly described. The purpose of this study was to evaluate the risk of mortality in patients with LR and determine if patient age is associated with mortality. METHODS: A total of 218 patients (144 male, 69 female; mean age 59 ± 15 years) with sacrococcygeal chordomas were reviewed. Cumulative incidence functions and competing risks for death due to disease and nondisease mortality were employed to analyze mortality trends following LR. RESULTS: The 10-year overall survival (OS) was 55%. Patients with LR had 44% 10-year OS, similar to patients without (59%; P = .38). The 10-year OS between those less than 55 compared with ≥55 years were similar (69% vs 48%; P = .52). The 10-year death due to disease was worse in patients with LR compared with those without (44% vs 84%; P < .001). In patients without LR, patients ≥55 years were 1.6-fold more likely to experience death due to other causes. CONCLUSIONS: Patients with an LR are more likely to die due to disease. Advanced patient age was associated with higher all-cause mortality following resection of sacral chordoma. LR of chordoma was associated with increased disease-specific mortality, regardless of age.

Low dose radiotherapy is associated with local complications but not disease control in sacral chordoma.

BACKGROUND: We reviewed the disease control and complications of the treatment of sacrococcygeal chordoma from four tertiary cancer centers with emphasis on the effects of radiotherapy in surgically treated patients. METHODS: A total of 193 patients with primary sacrococcygeal chordoma from 1990 to 2015 were reviewed. There were 124 males, with a mean age of 59 ± 15 years and a mean follow-up of 7 ± 4 years. Eighty-nine patients received radiotherapy with a mean total dose of 61.8 ± 10.9 Gy. RESULTS: The 10-year disease-free and disease-specific survival was 58% and 72%, respectively. Radiation was not associated with local recurrence (hazard ratio [HR], 1.13; 95% confidence interval [CI], 0.59-2.17; P = 0.71), metastases (HR, 0.93; 95% CI, 0.45-1.91; P = 0.85) or disease-specific survival (HR, 0.96; 95% CI, 0.46-2.00; P = 0.91). Higher doses (≥70 Gy; HR, 0.52; 95% CI, 0.20-1.32; P = 0.17) may be associated with reduced local recurrence. Radiotherapy was associated with wound complications (HR, 2.76; 95% CI, 1.64-4.82;, P < 0.001) and sacral stress fractures (HR, 4.73; 95% CI, 1.88-14.38; P < 0.001). CONCLUSIONS: In this multicenter review, radiotherapy was not associated with tumor outcome but associated with complications. The routine use of radiotherapy with en-bloc resection of sacrococcygeal chordomas should be reconsidered in favor of a selective, individualized approach with a radiation dose of ≥70 Gy.

How Often Do Acetabular Erosions Occur After Bipolar Hip Endoprostheses in Patients With Malignant Tumors and Are Erosions Associated With Outcomes Scores?

BACKGROUND: Bipolar endoprosthetic replacement is an option for reconstruction of the proximal femur to restore a functional extremity and salvage the limb. However, because these patients are young, there is a theoretical risk for long-term degenerative changes of the acetabulum. Currently, there is a paucity of data concerning the proportion of patients who experience degenerative acetabulum changes after reconstruction and whether these changes are associated with Musculoskeletal Tumor Society (MSTS) scores. QUESTIONS/PURPOSES: (1) What proportion of patients develop acetabular cartilage degeneration after bipolar hemiarthroplasty for malignant tumor-related reconstructions? (2) What is the survivorship free from revision for acetabular wear, erosions, or progressive arthritis? (3) Is there an association between the presence of acetabular erosions and lower MSTS scores? METHODS: Between 2000 and 2015, 148 patients underwent endoprosthetic reconstruction of the proximal femur with a bipolar hemiarthroplasty for a malignant tumor and were potentially eligible for this retrospective study. Minimum followup was 1 year except for those who died or were revised earlier; of the 148, no patients were lost to followup before that time who were not known to have died; mean followup on the remainder was 79 months (range, 12-220 months), and the mean time to death after surgery for those who died was 28 months (range, 0-196 months). Over the course of the study, 93 (63%) patients died. The mean (± SD) patient age was 57 ± 17 years, and 55% (81 of 148) of the patients were men. We used magnification-corrected supine AP plain radiographs of the hip to evaluate degenerative acetabulum changes, and we used the 1993 MSTS score to assess function through chart review and a longitudinally maintained institutional database. We used a competing-risks survivorship estimator rather than Kaplan-Meier because of the high proportion of patients who had died during the surveillance period. RESULTS: Nineteen patients (13%) developed cartilage erosion > 2 mm in the acetabulum, with two also developing protrusio after proximal femoral replacement with a bipolar endoprosthesis. Three additional patients also developed signs of protrusio. The mean acetabular wear after bipolar replacement was 1.2 mm. Patients with longer followup (p = 0.001) were at higher risk for developing acetabular wear. Six patients underwent conversion to THA to treat hip pain. At 10 years the cumulative incidence for conversion to THA for acetabular wear is 5% (95% confidence interval [CI], 0%-11%), whereas the cumulative incidence of death was 70% (95% CI, 61%-79%). There was no difference in mean MSTS scores between patients who developed > 2 mm of acetabular erosion (65% ± 25%) and those who did not (67% ± 20%; p = 0.77). CONCLUSIONS: Wear was uncommon among patients with malignant hip tumors treated with bipolar endoprostheses, but the followup here was short, and some patients indeed developed wear and underwent wear-related revisions to THA. Patients expected to survive more than a few years should have periodic radiographic surveillance and should be followed for a longer period to get a better sense for whether the problem worsens with time, as we expect it may, among patients who survive for longer periods. LEVEL OF EVIDENCE: Level III, therapeutic study.

Low frequency propagation through random polydisperse assemblies of cylindrical or spherical poroelastic obstacles.

The effective wavenumbers, moduli, and mass densities are found for polydisperse assemblies of poroelastic obstacles (considering fluid flow and solid deformation in the porous medium). The obstacles are infinite length cylinders and spheres. To achieve this, recent formulas for the effective wavenumbers, given by Linton and Martin [SIAM J. Appl. Math. 66(5), 1649-1668 (2006)] and Norris and Conoir [J. Acoust. Soc. Am. 129(1), 104-113 (2011)] in the dilute monodisperse case (obstacles of identical sizes in a fluid matrix), have been modified. Given the uncertainty in predicting the distribution in size of the obstacles, three quite different probability density functions are studied and compared: uniform, Schulz, and lognormal. Specifically, the Rayleigh approximation (low frequency regime) is considered, in which the wavelengths can be assumed very large compared to the size of the obstacles. Within this limit, simplified formulas are provided for the concentrations depending on the parameter characterizing the size dispersion.

Proximal Femoral Allograft-Prosthetic Composites: Do They Really Restore Bone? A Retrospective Review of Revision Allograft-Prosthetic Composites.

BACKGROUND: Large bone deficiencies are a challenging problem, historically treated with an allograft-prosthetic composite (APC) or megaprosthesis. There were several advantages of the APC compared with early megaprostheses, including the theoretical benefit of restoring bone stock. To our knowledge, there are no studies that have evaluated this claim. Our purpose was to review our institution's experience with APCs of the proximal femur that underwent revision for an aseptic cause and determine if the allograft bone was retained or removed during the revision procedure. METHODS: We identified 203 proximal femoral allograft prosthetic composites placed from 1988 through 2014. Twenty-seven of these patients underwent a revision because of an aseptic cause. Three categories were devised to classify the amount of allograft retention: type A, complete allograft retention; type B, partial retention; and type C, no allograft retention. RESULTS: The mean time from the initial APC to revision surgery was 5 years. The most common indication for revision included failure of the allograft (loosening or fracture). At the time of revision, there were 3 type A cases (11%), 4 type B cases (15%), and 20 type C cases (74%). Three of the 4 type B cases used the retained allograft as a strut graft around a newly inserted megaprosthesis. CONCLUSION: The results of this study are contradictory to previous literature that suggests APCs restore bone stock. In this series, the allograft was retained in only a small percentage of cases when the APC was revised for an aseptic cause. LEVEL OF EVIDENCE: IV.

Adamantinoma of bone: Long-term follow-up of 46 consecutive patients.

BACKGROUND: Adamantinomas are rare bone tumors, commonly affecting the tibia. Due to the rare nature of disease, previous studies are small or from multiple centers. The purpose of this study is to investigate outcomes of patients with adamantinoma treated in a single institution. METHODS: Forty-six histological confirmed adamantinomas of the extremities were reviewed at our institution between 1939 and 2012. Follow-up data included clinical and radiographical information focusing on complications, local recurrence, metastasis, and overall survival after the treatment. The mean follow-up was 16 years (range 2-42 years). RESULTS: The most common location was the tibia (n = 31). Patients commonly presented with pain and swelling. The mean age was 24 years (7-79 years). Thirty-seven patients were treated with limb salvage. The 39% of patients required a reoperation. The 10-year disease specific- and recurrence free survival was 92% and 72%, with three patients having a recurrence over 15 years postoperative. Older (> 20 years) patients and males were at increased risk of local recurrence (P < 0.05). CONCLUSION: Treatment of adamantinoma of the long bone consists of limb-salvage surgery. Male patients should be cautioned on their increased risk of disease recurrence, and advocate for continued surveillance of patients even greater than 15-years postoperatively due to late tumor recurrence.

Routine antenatal ultrasound in low- and middle-income countries: first look - a cluster randomised trial.

OBJECTIVE: Ultrasound is widely regarded as an important adjunct to antenatal care (ANC) to guide practice and reduce perinatal mortality. We assessed the impact of ANC ultrasound use at health centres in resource-limited countries. DESIGN: Cluster randomised trial. SETTING: Clusters within five countries (Democratic Republic of Congo, Guatemala, Kenya, Pakistan, and Zambia) METHODS: Clusters were randomised to standard ANC or standard care plus two ultrasounds and referral for complications. The study trained providers in intervention clusters to perform basic obstetric ultrasounds. MAIN OUTCOME MEASURES: The primary outcome was a composite of maternal mortality, maternal near-miss mortality, stillbirth, and neonatal mortality. RESULTS: During the 24-month trial, 28 intervention and 28 control clusters had 24 263 and 23 160 births, respectively; 78% in the intervention clusters received at least one study ultrasound; 60% received two. The prevalence of conditions noted including twins, placenta previa, and abnormal lie was within expected ranges. 9% were referred for an ultrasound-diagnosed condition, and 71% attended the referral. The ANC (RR 1.0 95% CI 1.00, 1.01) and hospital delivery rates for complicated pregnancies (RR 1.03 95% CI 0.89, 1.20) did not differ between intervention and control clusters nor did the composite outcome (RR 1.09 95% CI 0.97, 1.23) or its individual components. CONCLUSIONS: Despite availability of ultrasound at ANC in the intervention clusters, neither ANC nor hospital delivery for complicated pregnancies increased. The composite outcome and the individual components were not reduced. TWEETABLE ABSTRACT: Antenatal care ultrasound did not improve a composite outcome that included maternal, fetal, and neonatal mortality.

Long-Term Outcome of Hip Arthroplasty in the Setting of Synovial Chondromatosis.

BACKGROUND: Synovial chondromatosis (SC) is a rare disease involving cartilaginous metaplasia of synovial tissue. Treatment via synovectomy and loose body removal alone results in elevated recurrence rates, with up to 1 in 5 patients requiring conversion to a hip arthroplasty. The purpose of this study is to investigate outcomes of hip arthroplasty in the setting of SC, focusing on (1) disease-specific survival, (2) implant survivorship and complications, and (3) clinical outcomes. METHODS: We identified 26 patients with histologically confirmed SC who underwent hip arthroplasty between 1970 and 2015. Mean follow-up and patient age were 10 years (range 2-35) and 55 years (range 26-82), respectively. At the time of arthroplasty, 21 (81%) patients had "active" disease and underwent synovectomy. No constrained acetabular components were used. Six patients (23%) had a preoperative flexion contracture. RESULTS: The 15-year disease-free survival was 89%. Recurrence occurred in 3 patients at a mean of 0.8 years (range 0.03-1.2) postoperatively. Thirteen patients (50%) sustained a complication [most commonly aseptic loosening (n = 3, 12%)] and 7 required revision surgery. The 10-year and 15-year revision-free survival was 82% and 64%, respectively. Mean Harris Hip Score improved significantly from 50 (range 23-85) preoperatively to 82 (range 44-100) postoperatively (P < .001). CONCLUSION: Arthroplasty with simultaneous synovectomy provides reliable pain relief and excellent disease-specific survival at long-term follow-up; however, revision and complication rates were high.

Long-Term Outcome of Hip Arthroplasty in the Setting of Pigmented Villonodular Synovitis.

BACKGROUND: Pigmented villonodular synovitis (PVNS) is a rare, benign, painful proliferation of the synovium previously treated successfully with total hip arthroplasty (THA). Published results come from small series; therefore, the purpose of this study is to investigate the outcomes of THA in the setting of PVNS. METHODS: We identified 25 patients with histologically confirmed, diffuse PVNS who underwent THA between 1971 and 2013. Mean follow-up and age was 10 years and 39 years. Before arthroplasty, 16 patients (64%) had at least 1 surgical procedure (mean, 1; range, 1-3) to treat PVNS. Twenty (80%) patients had "active" disease and underwent synovectomy. No constrained acetabular components were used. RESULTS: The 10-year disease free-survival was 100%. Recurrence occurred in 1 patient at 24 years postoperatively. Nineteen patients (76%) sustained a complication (most commonly component loosening (n = 12 [48%]), and 16 required revision surgery. The 10-year revision-free survival was 66% for conventional polyethylene implants and 100% for highly cross-linked polyethylene devices. Mean Harris Hip Score improved significantly from 48 (range, 23-69) preoperatively to 78 (range, 47-96) postoperatively (P < .001). CONCLUSION: THA in the setting of PVNS improves patient function with a low rate of local recurrence. Complication and revision rates are high in this series likely owing to the young and active patient population and the use of conventional polyethylene. Modern bearings theoretically reduce the risk of revision.

How Does the Level of Nerve Root Resection in En Bloc Sacrectomy Influence Patient-Reported Outcomes?

BACKGROUND: For patients with sacral tumors, who are well enough for surgery, en bloc resection is the preferred treatment. Survival, postoperative complications, and recurrent rates have been described, but patient-reported outcomes often are not included in these studies. QUESTIONS/PURPOSES: The purposes of this study were (1) to compare patient-reported outcomes after en bloc sacrectomy, based on the level of sacral nerve root resection, in terms of mental health, physical health, bowel function, and sexual function; and (2) to assess differences in terms of mental health, physical health, and pain between patients with and without a colostomy. METHODS: A total of 74 patients, of whom 58 (78%) were diagnosed with chordoma, were surveyed between February 2012 and October 2014. This represented 48% of patients with sacral chordoma who were alive and who had been treated with a transverse sacral resection between June 2000 and August 2013 at three institutions with a minimum followup of 6 months (mean, 59 months; range, 6-255 months). We chose 6 months because we believe that neurologic deficits generally are stable by this point and that patients generally have recovered from the operation by this time. Patients were divided into five groups based on the most caudal nerve root spared: L5 (N = 10), S1 (N = 22), S2 (N = 17), S3 (N = 18), and S4 (N = 7). Only postoperative outcomes were collected using the National institute of Health's Patient Reported Measurement Information System (PROMIS) Global Health survey, PROMIS Pain Interference survey, PROMIS Pain Intensity survey, PROMIS Sexual Function survey, and the Modified Obstruction and Defecation Score survey. RESULTS: Differences between two adjacent levels were found in terms of mental health, physical health, and sexual function. Patients in whom the S2 nerve roots were spared had a lower mental health score (median = 44, interquartile range [IQR] = 41-51) than patients in whom the S3 nerve roots were spared (median = 53, IQR = 48-56, q = 0.049). Patients in whom the S2 nerve roots were spared had a slightly lower physical health score (median = 42, IQR = 40-51) than patients in whom the S3 nerve roots were spared (median = 47, IQR = 45-54, q = 0.043). Patients in whom the S1 roots were spared (median = 1.0, range = 1.0-1.0) had a lower orgasm score than patients in whom the S2 nerve roots were spared (median = 3, range = 2-5, q = 0.027). No differences in terms of mental health, physical health, or pain were found between the colostomy group and the no colostomy group. CONCLUSIONS: The combination of our findings can be used to further educate patients and discuss expectations. In an operative setting, these data can be considered when deciding to place a colostomy. LEVEL OF EVIDENCE: Level III, therapeutic study.

Durability of Hemiarthroplasty for Pathologic Proximal Femur Fractures.

BACKGROUND: The hip is a common location for metastatic tumors. Due to the high loads placed through the proximal femur, surgery is often indicated to provide pain relief and restore function. Historically, these lesions are reconstructed with a hemiarthroplasty; however, there are few reports on the outcome of these reconstructions. The purpose of this study is to evaluate the outcome of hemiarthroplasty for the treatment of proximal femur metastatic disease, with a specific focus on the rates of conversion to total hip arthroplasty (THA). METHODS: One hundred ninety-nine patients (102 women, 97 men) were treated using a hemiarthroplasty to reconstruct the proximal femur for metastatic disease between 1992 and 2014. Mean age and body mass index were 62 years and 27.4 kg/m2, respectively. The most common site of primary disease was the breast (n = 63). The most common location for the metastatic disease was the femoral neck (n = 148). Mean follow-up for surviving patients was 4 years. RESULTS: Over the course of the study, 2 (1%) patients underwent conversion to a THA due to groin pain and degenerative changes. In addition, complications occurred in 12% of patients, most commonly a deep venous thrombosis (n = 5). Following the procedure, mean Harris Hip Score and Musculoskeletal Tumor Society 1993 scores were 73 and 63%, respectively. CONCLUSION: Reconstruction of the proximal femur with a hemiarthroplasty endoprosthesis provides a majority of patients with a durable means of reconstruction, with a low rate of conversion to THA.

High Rate of Local Recurrence and Complications Following Total Knee Arthroplasty in the Setting of Synovial Chondromatosis.

BACKGROUND: Synovial chondromatosis is a rare, monoarticular arthropathy due to synovial metaplasia. There is a paucity of data examining the outcome of total knee arthroplasty (TKA) in the setting of synovial chondromatosis. The purpose of this study is to investigate the outcome and function in patients undergoing TKA for management of synovial chondromatosis. METHODS: Twenty patients who received TKA for synovial chondromatosis over a 25-year period were identified for analysis and followed for a mean of 7 years. There were 12 males and 8 females, with a mean age and body mass index of 63 years and 30.7 kg/m2. Seventeen patients had "active" disease at the time of surgery. RESULTS: The 5-year disease-free survival was 73%. Five patients sustained a recurrence that was treated with synovectomy and revision TKA (n = 2), observation (n = 2), and transfemoral amputation (n = 1) due to malignant degeneration to chondrosarcoma. One of the revision TKA patients underwent a transfemoral amputation 4 months later for recurrence. The overall rate of amputation was 10%. Nine patients (45%) sustained a complication, most commonly decreased knee motion (n = 7), leading to a revision TKA in 3 patients (15%). Mean preoperative knee range of motion was 73°, which improved to 97° postoperatively. The Knee Society Score and functional assessment improved from 35 and 42 preoperatively to 74 and 67 following TKA. CONCLUSION: TKA in the setting of synovial chondromatosis improves patient function and knee range of motion; however, there is a high rate of local recurrence and complications.

Direct Evidence of Solution-Mediated Superoxide Transport and Organic Radical Formation in Sodium-Oxygen Batteries.

Advanced large-scale electrochemical energy storage requires cost-effective battery systems with high energy densities. Aprotic sodium-oxygen (Na-O2) batteries offer advantages, being comprised of low-cost elements and possessing much lower charge overpotential and higher reversibility compared to their lithium-oxygen battery cousins. Although such differences have been explained by solution-mediated superoxide transport, the underlying nature of this mechanism is not fully understood. Water has been suggested to solubilize superoxide via formation of hydroperoxyl (HO2), but direct evidence of these HO2 radical species in cells has proven elusive. Here, we use ESR spectroscopy at 210 K to identify and quantify soluble HO2 radicals in the electrolyte-cold-trapped in situ to prolong their lifetime-in a Na-O2 cell. These investigations are coupled to parallel SEM studies that image crystalline sodium superoxide (NaO2) on the carbon cathode. The superoxide radicals were spin-trapped via reaction with 5,5-dimethyl-pyrroline N-oxide at different electrochemical stages, allowing monitoring of their production and consumption during cycling. Our results conclusively demonstrate that transport of superoxide from cathode to electrolyte leads to the nucleation and growth of NaO2, which follows classical mechanisms based on the variation of superoxide content in the electrolyte and its correlation with the crystallization of cubic NaO2. The changes in superoxide content upon charge show that charge proceeds through the reverse solution process. Furthermore, we identify the carbon-centered/oxygen-centered alkyl radicals arising from attack of these solubilized HO2 species on the diglyme solvent. This is the first direct evidence of such species, which are likely responsible for electrolyte degradation.

Estimating the Coherence of Noise in Quantum Control of a Solid-State Qubit.

To exploit a given physical system for quantum information processing, it is critical to understand the different types of noise affecting quantum control. Distinguishing coherent and incoherent errors is extremely useful as they can be reduced in different ways. Coherent errors are generally easier to reduce at the hardware level, e.g., by improving calibration, whereas some sources of incoherent errors, e.g., T_{2}^{*} processes, can be reduced by engineering robust pulses. In this work, we illustrate how purity benchmarking and randomized benchmarking can be used together to distinguish between coherent and incoherent errors and to quantify the reduction in both of them due to using optimal control pulses and accounting for the transfer function in an electron spin resonance system. We also prove that purity benchmarking provides bounds on the optimal fidelity and diamond norm that can be achieved by correcting the coherent errors through improving calibration.

Functional and oncologic outcome of cemented endoprosthesis for malignant proximal femoral tumors.

BACKGROUND: Cemented endoprosthetic replacement is an option for reconstruction of the proximal femur to achieve limb salvage. Existing outcome studies combine benign and malignant conditions, or group endoprostheses from multiple areas into one cohort. We sought to examine a series of endoprosthetic replacements of the proximal femur for a malignant process. METHODS: We reviewed 204 patients who underwent an endoprosthesis for a malignant process of the proximal femur with at least 2-year follow-up. Mean age was 59 years, with 55% being male. The most common pathology was metastatic disease (n = 120, 59%). Mean follow-up was 7 years (2-22 years). Mean time to death was 2 years (range 2 weeks-18 years). A bipolar component was used in 93% of patients. RESULTS: 5-year survival was 8% in patients with metastatic disease and 54% for patients with primary disease. Local recurrence and metastatic disease developed in 5 and 19 patients with a primary sarcoma. Following the procedure the mean Harris Hip and Musculoskeletal Tumor Society Scores were 75 and 18. CONCLUSION: Patients typically succumb to their disease prior to implant failure; however, endoprosthetic replacement provides patients with an acceptable means of functional recovery with an acceptable complication profile. J. Surg. Oncol. 2016;114:501-506. © 2016 Wiley Periodicals, Inc.

The Chitranjan Ranawat Award: Running Subcuticular Closure Enables the Most Robust Perfusion After TKA: A Randomized Clinical Trial.

BACKGROUND: Maintaining robust perfusion is an important physiologic parameter in wound healing. The effect of different closure techniques on wound perfusion after total knee arthroplasty (TKA) has not been established previously and may have implications for wound healing. QUESTIONS/PURPOSES: We asked whether a running subcuticular, vertical mattress, or skin staple closure technique enables the most robust wound perfusion after TKA as measured by laser-assisted indocyanine green angiography (LA-ICGA) in patients without specific risk factors for wound healing complications. METHODS: Forty-five patients undergoing primary TKA without comorbidities known to impact wound healing and perfusion were prospectively randomized to receive superficial skin closure with one of the following techniques: (1) running subcuticular (3-0 monofilament); (2) vertical mattress (2-0 nylon); or (3) skin staples. Twenty procedures were performed by RTT, 15 by RJS, and 10 by FHS. All surgeons used an anterior skin incision over the medial third of the patella in combination with a median parapatellar arthrotomy. Perfusion was assessed with a LA-ICGA device and software system immediately after closure to quantify fluorescence. Twenty-seven points were assessed immediately after closure in the operating room in each patient (nine along the incision and nine pairs medial and lateral to the incision). Mean incision perfusion was determined from the nine points along the incision with higher values indicating greater blood flow. Mean perfusion impairment was determined by calculating the difference between the nine pairs of surrounding skin and the nine points along the incision with smaller values indicating less perfusion impairment. These parameters were compared with analysis of variance (ANOVA) and subsequent pairwise comparisons with an unadjusted analysis as well as a multivariate analysis that adjusted for age, sex, and body mass index. Patients were followed for a mean of 7 months after surgery (range, 3-12 months) for possible incision-related complications. No patents were lost to followup. RESULTS: Running subcuticular closure demonstrated the best overall perfusion. Mean incision perfusion in fluorescent units with SD was as follows: running subcuticular, 64 (16); vertical mattress, 32 (18); and staples, 19 (7) (ANOVA p < 0.001). The running subcuticular closure demonstrated the least impairment of perfusion among the closures compared. Mean perfusion impairment was as follows: running subcuticular, 21 (12); vertical mattress, 37 (24); and staples, 69 (27) (ANOVA p < 0.001). All Tukey-adjusted pairwise comparisons from both metrics likewise favored the subcuticular closure (p < 0.001) both before and after adjusting for age, sex, and body mass index. One patient in the vertical mattress cohort experienced a surgical site infection; no other wound-related complications were observed in this study. CONCLUSIONS: The method of closure can influence skin and soft tissue perfusion after TKA. Running subcuticular closure enables the most physiologic robust blood flow, which may improve wound healing. However, the clinical importance of these findings remains uncertain, because patients in this study were selected because they lacked risk factors for wound healing complications. Studies with this modality in specific patient populations at higher risk for wound complications will be necessary to quantify the clinical advantage of using running subcuticular closure. LEVEL OF EVIDENCE: Level I, therapeutic study.