The impact of operative approach and intraoperative imaging on leg length discrepancy and acetabular component angle in total hip arthroplasty: a retrospective cohort study.

PURPOSE: Operative approach in total hip arthroplasty (THA) has long been a topic of debate with each approach having unique benefits and disadvantages. One purported benefit of an anterior approach to THA is that it allows for intraoperative positioning using fluoroscopy rather than manual positioning. Proper positioning allows for improved outcomes including leg length discrepancy and acetabular component angle. This study aims to examine if operative approach and use of imaging in intraoperative positioning impact LLD and cup angle post-operatively. METHODS: A total of 300 hips were enrolled in the study with 100 hips per approach (anterior with fluoroscopy, lateral, and posterior). Retrospective chart review was conducted to assess patient demographics and radiographic analysis used to determine LLD and acetabular cup angle. RESULTS: Of the three groups, those receiving anterior approach THAs were on average older than those in the posterior group. Analysis comparing the LLD and acetabular angle across the three groups showed no statistically significant difference in LLD (p=0.091); this was also reflected when comparing hips that received fluoroscopy with those that did not (p=0.91). For acetabular angle, while no difference existed when comparing hips that received imaging versus those that did not, statistically significant differences were observed when comparing the three intraoperative approaches (p<0.0001). CONCLUSIONS: Neither intraoperative approach nor the use of intraoperative imaging in THA has a statistically significant effect on LLD post-operatively. However, approach did impact the acetabular cup angle across all three distinct approaches.

Impact of the coronavirus disease 2019 pandemic on equity of access to hip and knee replacements: a population-level study.

PURPOSE: The COVID-19 pandemic had innumerable impacts on healthcare delivery. In Canada, this included limitations on inpatient capacity, which resulted in an increased focus on outpatient surgery for non-emergent cases such as joint replacements. The objective of this study was to assess whether the pandemic and the shift towards outpatient surgery had an impact on access to joint replacement for marginalized patients. METHODS: Data from Ontario's administrative healthcare databases were obtained for all patients undergoing an elective hip or knee replacement between January 1, 2018 and August 31, 2021. All surgeries performed before March 15, 2020 were classified as "pre-COVID," while all procedures performed after that date were classified as "post-COVID." The Ontario Marginalization Index domains were used to analyze proportion of marginalized patients undergoing surgery pre- and post-COVID. RESULTS: A total of 102,743 patients were included-42,812 hip replacements and 59,931 knee replacements. There was a significant shift towards outpatient surgery during the post-COVID period (1.1% of all cases pre-COVID to 13.2% post-COVID, p < 0.001). In the post-COVID cohort, there were significantly fewer patients from some marginalized groups, as well as fewer patients with certain co-morbidities, such as congestive heart failure and chronic obstructive pulmonary disease. CONCLUSION: The most important finding of this population-level database study is that, compared to before the COVID-19 pandemic, there has been a change in the profile of patients undergoing hip and knee replacements in Ontario, specifically across a range of indicators. Fewer marginalized patients are undergoing joint replacement surgery since the COVID-19 pandemic. Further monitoring of access to joint replacement surgery is required in order to ensure that surgery is provided to those who are most in need.

Licensed and Liable. Insurance, Road Regulations, and Driving After Hip and Knee Arthroplasty Surgery.

BACKGROUND: There is a reliance on surgeons to provide advice to patients regarding safe return to driving following hip or knee arthroplasty. Concerns arise that misinformation may place the surgeon in a position of potential legal implication. The purpose of this article is to inform surgeons of their role in accordance with advice from insurance companies and transport regulatory bodies. METHODS: We sought the stipulations from 5 of the top 10 insurance companies in the United States, Canada, Australia, and the United Kingdom and the transport regulatory body of each country with regards to guidelines on driving after arthroplasty surgery. RESULTS: The transport regulatory bodies of the countries evaluated do not provide explicit recommendations regarding return to driving after hip or knee arthroplasty and place the responsibility of determining fitness to drive on the treating doctor. Insurance company policies do not contain specifics pertaining to driving after surgery and in most cases defer to the treating doctor to make this decision. Guidelines are available in Canada and America with suggested timeframes on return to driving following arthroplasty surgery. CONCLUSION: Advice regarding return to driving following hip or knee arthroplasty should be individualized for each patient; ultimately the patient must feel safe to drive knowing that they have a legal responsibility to remain in control of the vehicle at all times. It is recommended that surgeons document any discussion regarding return to driving and should not feel that they are contravening any prescriptive regulation by allowing driving when appropriate.

The International Initiative to Measure Perceived Risk in Arthroplasty: The Results From a Multinational Survey.

BACKGROUND: There is an inherent moral imperative to avoid complications from arthroplasty. Doing so at ideal cost is also associated with surgeon reputation, and, increasingly in health care delivery systems that measure and competitively score outcomes, reimbursement to the surgeons and their hospitals. As a result, patients who are perceived to be in higher risk comorbidity groups, such as the obese and diabetics, as well as those challenged by socioeconomic factors may face barriers to access elective arthroplasty. METHODS: In this initiative, surveys were sent to surgeons in 8 different countries, each adapted for their own unique payment, remuneration, and punitive models. The questions in the surveys pertained to surgeons' perception of risk regarding medical and socioeconomic factors in patients indicated for total hip or knee arthroplasty. This paper primarily reports on the results from Canada, Ireland, and the United Kingdom. RESULTS: The health care systems varied between a universal/state funded health care system (Canada) to those that were almost exclusively private (India). Some health care systems have "bundled" payment with retention of fees for postoperative complications requiring readmission/reoperation and including some with public publication of outcome data (United States and the United Kingdom), whereas others had none (Canada). There were some major discrepancies across different countries regarding the perceived risk of diabetic patients, who have variable Hemoglobin A1c cut-offs, if any used. However, overall the perception of risk for age, body mass index, age, sex, socioeconomic, and social situations remained surprisingly consistent throughout the health care systems. Any limitations set were primarily driven by surgeon decision making and not external demands. CONCLUSION: Surgeons will understandably try and optimize the health status of patients who have reversible risks as shown by best available evidence. The evidence is of variable quality, and, especially for irreversible social risk factors, limited due to concerns over cost and quality outcomes that can be influenced by experience-driven perceptions of risk. The results show that perceptions of risk do have such influence on access across many health care delivery environments. The authors recommend better risk-adjustment models for medical and socioeconomic risk factors with possible stratification/exclusions regarding reimbursement adjustments and reporting to help reverse disparities of access to arthroplasty.

The influence of the COVID-19 pandemic on total hip and knee arthroplasty in Ontario: a population-level analysis.

BACKGROUND: The effects of the COVID-19 pandemic on elective orthopedic surgery have yet to be reported at the population level in Canada. We sought to detail the effect of the pandemic on patients who underwent total hip arthroplasty (THA) and total knee arthroplasty (TKA), and on surgeons with respect to surgical volume, wait times and health care quality. METHOD: We compared patient length of hospital stay, revisions, readmissions and emergency department presentations between pre-pandemic (April 2019 to February 2020) and postpandemic (April 2020 to February 2021) cohorts of patients who underwent inpatient THAs or TKAs. Wait times for THA and TKA in Ontario were similarly collected. RESULTS: Case volumes for THA and TKA decreased by 30% during the pandemic. There were significantly fewer medically complex cases during this time period (p < 0.001). Length of hospital stay was reduced from 2.2 to 1.8 days (p < 0.001). Patients were less likely to visit the emergency department within 30 days of surgery (p < 0.001). Patients who underwent TKA were also more likely to be discharged directly home (p = 0.025). There was no difference in rate of revision surgery or readmission within 30 days. The proportion of patients meeting the standard benchmark wait time in Ontario was significantly lower (p < 0.001). The corresponding wait time to treatment increased significantly (p < 0.001). CONCLUSION: The effects of the COVID-19 pandemic on elective THA and TKA case volumes and wait times was significant. Patients having surgery during the pandemic were less medically complex, had shorter length of hospital stays and had significantly less health care utilization.

Risk of Total Hip Arthroplasty After Acetabular Fracture Fixation: The Importance of Age.

BACKGROUND: Geriatric patients are the most rapidly growing cohort of patients sustaining acetabular fractures (AFs). The purpose of this study was to examine the risk of a secondary total hip arthroplasty (THA) in older patients (>60 year old) with a prior AF open reduction internal fixation (ORIF) compared with younger patients (<60 year old) with an AF ORIF on a large population level. METHODS: Using administrative health care data from 1996 to 2010 inclusive of all 202 hospitals in Ontario, Canada, all adult patients with an AF ORIF and a minimum of two year follow-up were identified and included. The risk of THA was examined using a Cox proportional hazards model adjusting for patient risk factors. Secondary outcomes included surgical complications and all-cause mortality. RESULTS: A total of 1725 patients had an AF ORIF; 1452 (84.2%, mean age of 38.3 ± 12.1 years) aged <60 years ("younger") and 273 (15.8%, mean age of 69.9 ± 7.8 years) > 60 years ("older"). The mean (SD) follow-up time for all patients was 6.9 (4.2) years. In older patients, 19.4% (53 of 273) went on to receive a secondary THA with a median time to event of 3.9 years, compared with 12.9% (187 of 1452) in the younger patient cohort with a median time of 6.9 years (HR 1.7, 95% CI: 1.2-2.3). As expected, older patients had a higher 90-day mortality rate compared with younger patients (7.7% vs. 0.7%, respectively; HR 9.2, 95% CI: 4.3-19.9; P < .001). CONCLUSION: Older patients with an AF ORIF are at a significantly higher risk for a secondary THA than younger patients with an AF ORIF.

Temporal Trends and Predictors of Thirty-Day Readmissions and Emergency Department Visits Following Total Knee Arthroplasty in Ontario Between 2003 and 2016.

BACKGROUND: Total knee arthroplasty (TKA) is the second most common surgery performed in Canada. Understanding and improving quality metrics associated with such high-volume procedures is of utmost importance to maximize value within the healthcare system, which is a balance between cost and quality. Although rates and predictors of hospital readmission and emergency department (ED) visits following TKA have previously been described in privatized healthcare settings, few studies have evaluated trends in length of stay (LOS), hospital readmissions, and ED visits following TKA in a universal single-payer system. METHODS: Using data from a provincially held and validated registry, the Institute for Clinical and Evaluative Sciences, we undertook a review of all 205,152 TKAs performed in the province of Ontario, Canada, between 2003 and 2016. We determined temporal trends in utilization, LOS, readmissions, and ED visits and evaluated patient and provider predictors of hospital readmissions and ED visits using multivariate logistic regression modeling. We also grouped and described the most common reasons for readmission and ED visits based on the available International Classification of Diseases, Ninth Revision and Tenth Revision coding information. RESULTS: LOS decreased significantly over the study period (P < .0001), from a median of 5 days (10th percentile 3 days, 90th percentile 8 days) in 2003 to a median of 3 days (10th percentile 2 days, 90th percentile 4 days) in 2016. All-cause 30-day readmissions did not change significantly over the study period, but the rate of ED visits increased significantly over time. Predictors of 30-day readmission following TKA included older age, male gender, lower income quartile, not having a postoperative visit with a primary care physician (PCP), increased comorbidities, longer LOS, urgent or revision surgery, admission to a teaching hospital, and discharge to an inpatient rehabilitation facility. Variables that predicted increased odds of an ED visit included older age, male gender, lower income quartile, not having a postop visit with a PCP, increasing comorbidities, year of surgery, longer LOS, and revision surgery. Admission to a teaching hospital and discharge to an inpatient rehabilitation facility showed a trend toward increased odds of an ED visit. CONCLUSIONS: We identified a significant increase in ED visits following TKA in Ontario between 2003 and 2016, with no corresponding increase in hospital readmissions despite a significant temporal trend toward shorter LOS. Predictors of ED visits and readmissions were similar, including male gender, lower income, higher comorbidities, and lacking a PCP visit postoperatively. Increased rates of ED visits following TKA in Ontario represent a quality problem, as they are associated with increased cost to the public healthcare system without any substantial benefit. Interventions aimed at redirecting patients from the ED for minor postoperative concerns should be investigated, as this is likely to improve care by reducing costs, improving efficiency, and enhancing patient experience.

A Large-Scale Fifteen-Year Minimum Survivorship of a Cementless Triple Tapered Femoral Stem.

BACKGROUND: This study reports the long-term outcomes of a metaphyseal fit-and-fill cementless femoral component in total hip arthroplasty (THA) with a follow-up of 15-19 years. METHODS: We conducted a retrospective review of 376 consecutive THAs (345 patients), using a triple tapered stem performed between 2000 and 2003 with a view to assessing survivorship and radiological and functional outcomes. Images were assessed for initial alignment, terminal osteolysis, or subsidence, while clinical outcomes were assessed using the St Michael's Hip Score. RESULTS: Forty-five (11.9%) hips were lost to follow-up, 20 (5.31%) had died before our 15-year cutoff follow-up, and 4 (1.06%) had declined follow-up early on, leaving 307 hips (81.64%, 276 patients) available for both clinical and radiological follow-up at a minimum of 15 years (range 15-19). The mean age at the time of operation was 49.6 years (range 19-71) and the cohort included 131 (42.67%) male and 145 (47.23%) female patients. Seven stems (2.28%) were revised: 4 due to periprosthetic fractures, 2 for periprosthetic joint infection, and 1 for adverse reaction to metal debris at the trunnion. The St Michael's Hip Score improved from 14.2 (range 9-23) preoperatively to 22.3 (range 13 to 25) at the last documented follow-up (P = .000). Kaplan-Meier survivorship with stem revision for any reason as the end point was 97.70%. Worst-case scenario Kaplan-Meier survivorship, where all lost to follow-up are considered as failures, was 85.3%. No stem was revised for aseptic loosening. CONCLUSION: This triple tapered stem in THA shows excellent survivorship beyond a minimum of 15 years.

The early- to medium-term results of a hemispherical, porous coated acetabular shell with multiple different bearing combinations are excellent with the exception of metal-on-metal.

PURPOSE: This study prospectively reports survivorship and radiographic and clinical outcomes following primary elective total hip arthroplasty (THA) using a novel single hemispherical, porous-coated acetabular cup with five different bearing combinations and a minimum of five year follow-up. METHODS: Continuing post-market release monitoring of this cup, we prospectively enrolled 108 patients (121 THA) between 2009 and 2015. We followed this cohort by examining survivorship, in addition to clinical and radiological outcomes for metal-on-metal (MoM) compared with non-MoM bearing combinations (ceramic-on-ceramic, oxinium-on-polyethylene, ceramic-on-metal, and metal-on-polyethylene). RESULTS: All 108 (121 hips) patients were followed up. Average age at time of surgery was 45.1 years (range 19 to 71 years) of which 42.1% were males. A total of seven (5.8%) cups were revised, all of which were MoM. No osteolysis was observed in any of the patients at the latest visit with a mean follow-up of 9.1 ± 1.7 years (range 4.4-10.7 years). With MoM excluded, survivorship of the cup at five  years is 97.8%. Survivorship for MoM implants was 90.0%. Validated hip scores showed significant improvements for all bearing types and no significant difference between groups at latest follow-up (p = 0.614). There was no cup migration with any bearing surface. CONCLUSION: This cup showed excellent survivorship at five year follow-up, except for patients receiving a MoM articulation. While there were concerns over the early survivorship of this cup, our cohort and joint registry data confirm excellent outcomes.

Effect of Parkinson's Disease on Hemiarthroplasty Outcomes After Femoral Neck Fractures.

BACKGROUND: The purpose of this study was to evaluate the outcomes following hemiarthroplasty (HA) for femoral neck fractures (FNFs) in patients with Parkinson's disease (PD) compared with patients without PD. METHODS: This was a retrospective review utilizing the Nationwide Readmissions Database, a national database incorporating inpatient hospitalization information. Using the Nationwide Readmissions Database, patients who underwent HA for FNF between 2010-2014 were identified. International Classification of Diseases, 9th Revision, codes were used to find a subset of patients with PD. Primary outcomes of interest included death, hospital readmission, periprosthetic fracture, postoperative dislocation, any revision surgery, and revision surgery for instability, fracture, or infection. RESULTS: There were a total of 7721 (4%) patients with PD. There was no difference in the risk of death or any postoperative complications during index hospitalization for these patients. However, PD patients had an increased risk of hospital readmission (odds ratio [OR] = 1.13, 95% confidence interval [CI]: 1.02-1.26) and postoperative dislocation (OR = 2.10, 95% CI: 1.58-2.80) within 90 days of surgery. PD patients also had an increased risk of revision surgery for instability (OR = 2.20, 95% CI: 1.48-3.28), despite no difference in the risk of any revision surgery, revision surgery for fracture, or revision surgery for infection. CONCLUSION: In this retrospective cohort study, PD patients who underwent a HA for FNF had a greater risk of postoperative dislocation and revision surgery for instability within 90 days. These findings are not only important to consider when managing these at-risk patients but also stress the need to allocate operative and postoperative resources to prevent and treat instability. LEVEL OF EVIDENCE: 3 (Retrospective cohort study).

Patient-Reported Outcome Measures of Total Knee Arthroplasties for Post-Traumatic Arthritis versus Osteoarthritis: A Short-Term (5- to 10-year) Retrospective Matched Cohort Study.

BACKGROUND: The objective of the study was to compare the patient-reported outcome measures (PROM) of patients with post-traumatic arthritis (PTA) versus patients with osteoarthritis (OA) undergoing total knee arthroplasty (TKA) and compare the rates of revision among these two groups. METHODS: Using a prospectively held institutional registry, we retrospectively reviewed patients ≥60 years of age who underwent unilateral TKA between May 2007 and February 2012. Patients with previous or concomitant diagnosis of inflammatory arthropathy or an initial open fracture were excluded. PTA patients were matched 1:5 with OA patients undergoing TKA. Validated PROMs were recorded at baseline before index TKA and the last follow-up. Reason and time to revision surgery was reported, and survivorship was compared using Kaplan-Meier curves. RESULTS: Seventy-five PTA patients were matched to 375 OA patients. There was no difference between these groups with respect to age (67.7 ± 5.6 vs 67.8 ± 5.5 years; P = .876), body mass index (28.6 ± 5.4 vs 28.7 ± 5.3 kg/m2; P = .948), sex (65.3% vs 65.3% females; P = .999), Charlson Comorbidity Index (21.3% vs 21.3% Index 1-2, P = .999), and time to follow-up (93.0 ± 13.4 vs 88.2 ± 13.7 months; P = .999). No statistically significant difference was found in PROMs at baseline and the last follow-up (P > .05), the rate or time to revision surgery between the two groups (P-value = .635; log-rank test). CONCLUSION: Unlike previous studies, TKA for PTA does not pose lower PROMs or higher revision rates when compared to TKA for OA. These results could help provide surgeons with a frame of reference in terms of expectations for patients with PTA undergoing TKA.

Age-Related Functional Decline Following Total Knee Arthroplasty: Risk Adjustment is Mandatory.

BACKGROUND: Patient-reported outcome measures (PROMs) are being used increasingly to determine the success of total knee arthroplasty (TKA). Our goal is to investigate whether advanced age is associated with lower PROM scores. METHODS: We used our hospital's TKA registry to examine the relationship between age and PROMs in all patients 50-90 years of age who underwent unilateral or simultaneous bilateral primary TKA between 2007 and 2011 with a primary diagnosis of osteoarthritis. All 5 domains of the Knee Injury and Arthritis Outcomes Score (KOOS) and the Lower Extremity Activity Scale (LEAS) at baseline, 2 years, and 5 years were collected. The association between age and PROM score was assessed by piecewise linear regression using generalized estimating equations, adjusting for demographics, comorbidity, and baseline score. RESULTS: Significant nonlinear relationships among age, KOOS subdomains, and LEAS were found. The placement of the age spline knot was at 70 years for KOOS Symptom and 68 years for KOOS Pain, KOOS Activities of Daily Living (ADL), and LEAS. The KOOS Symptom domain showed a significant worsening between 2-year and 5-year follow-up (P < .05) as patients got older. CONCLUSION: We found an age-related decline in KOOS Pain, KOOS Symptom, KOOS ADL, and LEAS scores. The best fitting spline knots were at 68 (KOOS Pain, KOOS ADL, and LEAS) and 70 years (KOOS Symptoms), respectively. This demonstrates that there is a critical age at which functional decline begins regardless of the quality of the TKA surgery. Our findings will help surgeons accurately guide patient expectations after TKA based on age. LEVEL OF EVIDENCE: Level II, prognostic study.

The Ideal Total Hip Replacement Bearing Surface in the Young Patient: A Prospective Randomized Trial Comparing Alumina Ceramic-On-Ceramic With Ceramic-On-Conventional Polyethylene: 15-Year Follow-Up.

BACKGROUND: The optimum bearing surface for total hip arthroplasty remains debatable. We have previously published our outcome at 10 years and this represents the 15-year follow-up. METHODS: A total of 58 hips (in 57 patients with a mean age of 42 years) were randomized to receive either ceramic-on-ceramic (CoC) or ceramic-on-polyethylene (CoP) total hip arthroplasty. We prospectively followed for survivorship, functional outcomes (using the Harris Hip Score and the St Michael's Hip Score [SMH]), and radiological outcomes. RESULTS: At a minimum of 15 years, 3 patients had died, but not been revised. Seven were lost to follow-up. Five cases from the CoP group were revised (4 for polyethylene wear and osteolysis). Four from the CoC were revised; one each for head fracture, instability, infection, and trunnionosis. Both groups showed statistically significant improvements in Harris Hip Score scores and SMH functional scores, with no difference between the 2 bearings. For the CoP group, there was an improvement from 15.6 to 21.5 in the SMH and from 48.8 to 88.7 (P > .05); and for CoC, this improvement was 15.8 to 23.5 and 50.3 to 94.6 (P > .05), respectively. Mean wear rate of the polyethylene was 0.092 mm/y and for the CoC was 0.018 mm/y. Two patients in the CoC group had evidence of acetabular osteolysis vs 3 in the CoP. Six patients had femoral osteolysis in the CoC group and 12 in the CoP group. CONCLUSION: Survivorship and function of the 2 bearing groups remains comparable; while the polyethylene wear and osteolysis may represent issues in the future.

The effect of patient, provider and surgical factors on survivorship of high tibial osteotomy to total knee arthroplasty: a population-based study.

PURPOSE: The aim of this study was to identify the survivorship of high tibial osteotomy (HTO) to total knee arthroplasty (TKA) on a population level, and identify the patient, provider and surgical factors that influenced eventual TKA. METHODS: Administrative records from physician billings and hospital admissions were used to identify all adults in Ontario, Canada, who underwent an HTO from 1994 to 2010. The primary outcome was time to TKA, which was estimated using Kaplan-Meier (KM) survival analysis. A Cox proportional hazards model examined the risk associated with patient factors (age, sex, income and co-morbidity score), provider factors (hospital status, surgeon volume and surgeon year in practice) and surgical factors (concurrent ligament reconstruction or bone grafting; and previous chondral or meniscal surgery). RESULTS: A total of 2671 patients who underwent HTO met inclusion. The median age was 46 years (interquartile range 39-53 years), and 62 % were male. The KM survivorship of HTO to TKA at 10 years was 0.67 ± 0.01. Older age [HR 1.05 (95 % CI 1.04, 1.06), p < 0.001; 5 % increased risk for each year over age 46], female sex [HR 1.35 (95 % CI 1.17, 1.55), p < 0.001], higher comorbidity score [HR 1.58 (95 % CI 1.12, 2.22), p = 0.009] and a prior history of arthroscopy/meniscectomy [HR 1.24 (95 % CI 1.08, 1.43), p = 0.002] increased the risk of eventual TKA. However, HTO with concurrent ligament reconstruction was associated with lower [HR 0.62 (95 % CI 0.43, 0.88), p = 0.008] risk of eventual TKA. CONCLUSION: In this population, two-thirds of patients were able to avoid a TKA for 10 years after HTO. Specific factors such as older age, female sex, higher comorbidity and prior meniscectomy lowered survival rates. An understanding of patient risk factors for conversion to TKA may help guide surgeons in their selection of patients who will benefit most from HTO. LEVEL OF EVIDENCE: Retrospective cohort study, III.

Calcium efflux activity of plasma membrane Ca2+ ATPase-4 (PMCA4) mediates cell cycle progression in vascular smooth muscle cells.

We explored the role played by plasma membrane calcium ATPase-4 (PMCA4) and its alternative splice variants in the cell cycle of vascular smooth muscle cells (VSMC). A novel variant (PMCA4e) was discovered. Quantitative real-time-PCR-quantified PMCA4 splice variant proportions differed in specific organs. The PMCA4a:4b ratio in uninjured carotid arteries (∼1:1) was significantly reduced by wire denudation injury (to ∼1:3) by modulation of alternative splicing, as confirmed by novel antibodies against PMCA4a/e and PMCA4b. Laser capture microdissection localized this shift to the media and adventitia. Primary carotid VSMC from PMCA4 knock-out (P4KO) mice showed impaired [(3)H]thymidine incorporation and G1 phase arrest as compared with wild type (P4WT). Electroporation of expression constructs encoding PMCA4a, PMCA4b, and a PMCA4b mutant lacking PDZ binding rescued this phenotype of P4KO cells, whereas a mutant with only 10% of normal Ca(2+) efflux activity could not. Microarray of early G1-synchronized VSMC showed 39-fold higher Rgs16 (NFAT (nuclear factor of activated T-cells) target; MAPK inhibitor) and 69-fold higher Decorin (G1 arrest marker) expression in P4KO versus P4WT. Validation by Western blot also revealed decreased levels of Cyclin D1 and NFATc3 in P4KO. Microarrays of P4KO VSMC rescued by PMCA4a or PMCA4b expression showed reversal of perturbed Rgs16, Decorin, and NFATc3 expression levels. However, PMCA4a rescue caused a 44-fold reduction in AP-2ß, a known anti-proliferative transcription factor, whereas PMCA4b rescue resulted in a 50-fold reduction in p15 (Cyclin D1/Cdk4 inhibitor). We conclude that Ca(2+) efflux activity of PMCA4 underlies G1 progression in VSMC and that PMCA4a and PMCA4b differentially regulate specific downstream mediators.

Antibiotic Prophylaxis to Prevent Surgical Site Infections in Children: A Prospective Cohort Study.

OBJECTIVE: To investigate the association between antibiotic prophylaxis (AP) and surgical-site infection in pediatric patients. BACKGROUND: Surgical-site infections (SSIs) are a major cause of postoperative morbidity and mortality. Despite numerous studies in adults, benefit of AP in preventing SSIs in children is uncertain. METHODS: Patients aged 0 to 21 years who underwent surgical procedures at a pediatric acute care hospital from April 1, 2009, to December 31, 2010, were assessed. Antibiotic prophylaxis indication and administration according to an evidence-based guideline were recorded. Complete compliance was defined as AP given, when indicated, within 60 minutes before incision. Surgical-site infections were identified using the Centers for Disease Control and Prevention criteria and documented in the medical records using the International Classification of Diseases, Tenth Revision. Multiple logistic regressions adjusting for age, sex, American Society of Anesthesiologists status, wound classification, admission status, surgical discipline, and surgical duration evaluated association of AP compliance and SSI. RESULTS: Of 5309 patients for whom antibiotics were indicated, 3901 (73.5%) with complete compliance had an infection rate of 3.0%, whereas 1408 (26.5%) who were not compliant had an infection rate of 4.3% (adjusted relative risk: 0.7; 95% confidence interval: 0.5-0.9; P = 0.02). Of 4156 patients for whom antibiotics were not indicated, the 895 (21.5%) who received antibiotics had an infection rate of 1.7% compared with 0.7% in the 3261 (78.5%) who did not receive antibiotics (adjusted relative risk: 1.6; 95% confidence interval: 0.8-3.1; P = 0.18). CONCLUSIONS: In pediatric surgery, complete compliance with AP was associated with 30% decreased risk of SSI.

The sizing of hamstring grafts for anterior cruciate reconstruction: intra- and inter-observer reliability.

PURPOSE: The objective of this study was to establish the intra- and inter-observer reliability of hamstring graft measurement using cylindrical sizing tubes. METHODS: Hamstring tendons (gracilis and semitendinosus) were harvested from ten cadavers by a single surgeon and whip stitched together to create ten 4-strand hamstring grafts. Ten sports medicine surgeons and fellows sized each graft independently using either hollow cylindrical sizers or block sizers in 0.5-mm increments­the sizing technique used was applied consistently to each graft. Surgeons moved sequentially from graft to graft and measured each hamstring graft twice. Surgeons were asked to state the measured proximal (femoral) and distal (tibial) diameter of each graft, as well as the diameter of the tibial and femoral tunnels that they would drill if performing an anterior cruciate ligament (ACL) reconstruction using that graft. Reliability was established using intra-class correlation coefficients. RESULTS: Overall, both the inter-observer and intra-observer agreement were >0.9, demonstrating excellent reliability. The inter-observer reliability for drill sizes was also excellent (>0.9). Excellent correlation was seen between cylindrical sizing, and drill sizes (>0.9). CONCLUSIONS: Sizing of hamstring grafts by multiple surgeons demonstrated excellent intra-observer and intra-observer reliability, potentially validating clinical studies exploring ACL reconstruction outcomes by hamstring graft diameter when standard techniques are used. LEVEL OF EVIDENCE: III.

Outcomes of infection following pediatric spinal fusion.

BACKGROUND: Removal of instrumentation is often recommended as part of treatment for spinal infections, but studies have reported eradication of infection even with instrumentation retention by using serial débridements and adjuvant antibiotic pharmacotherapy. We sought to determine the effect of instrumentation retention or removal on outcomes in children with spinal infections. METHODS: We retrospectively reviewed the cases of patients who experienced early (< 3 mo) or late (≥ 3 mo) infected spinal fusions. Patients were evaluated at least 2 years after eradication of the infection using the following protocol outcomes: follow-up Cobb angle, curve progression and nonunion rates. RESULTS: Our sample included 35 patients. The mean age at surgery was 15.1 ± 6.0 years, 65.7% were girls, and mean follow-up was 41.7 ± 26.9 months. The mean Cobb angle was 63.6° ± 14.5° preoperatively, 29.4° ± 16.5° immediately after surgery and 37.2° ± 19.6° at follow-up. Patients in the implant removal group (n = 21) were more likely than those in the implant retention group (n = 14) to have a lower ASA score (71.4% v. 28.6%, p = 0.03), fewer comorbidities (66.7% v. 21.4%, p = 0.03), late infections (81.0% v. 14.3%, p = 0.01) and deep infections (95.2% v. 64.3%, p = 0.03). Implants were retained in 12 of 16 (75.0%) patients with early infections and 2 of 19 (10.5%) with late infections. Patients with implant removal had a higher pseudarthrosis rate (38.1% v. 0%, p = 0.02) and a faster curve progression rate (5.8 ± 9.8° per year v. 0.2 ± 4.7° per year, p = 0.04). CONCLUSION: Implant retention should be considered, irrespective of the timing or depth of the infection.

CONTEXTE: Le retrait des implants est souvent recommandé lors du traitement des infections rachidiennes, mais des études ont démontré qu'il est possible d'éliminer les infections tout en maintenant les implants en place, en ayant recours à des débridements répétés et à une antibiothérapie adjuvante. Nous avons voulu mesurer l'effet de la préservation ou du retrait des implants sur les résultats chez les enfants souffrant d'infections rachidiennes. MÉTHODES: Nous avons passé en revue de manière rétrospective des cas de fusions rachidiennes infectées à un stade précoce (< 3 mois) ou tardif (≥ 3 mois). Les patients ont été évalués au moins 2 ans après l'éradication de l'infection à l'aide des paramètres suivants : angle de Cobb, progression de la courbure et taux de non fusion au moment du suivi. RÉSULTANTS: Notre échantillon comprenait 35 patients. L'âge moyen au moment de la chirurgie était de 15,1 ± 6,0 ans; 65,7 % étaient des filles et le suivi moyen s'est échelonné sur 41,7 ± 26,9 mois. L'angle de Cobb moyen était de 63,6 ° ± 14,5 ° en période préopératoire, de 29,4 ° ± 16,5 ° immédiatement après la chirurgie et de 37,2 ° ± 19,6 ° au moment du suivi. Les patients du groupe soumis au retrait de l'implant (n = 21) étaient plus susceptibles que les patients du groupe chez qui l'implant est demeuré en place (n = 14) de présenter un score ASA plus bas (71,4 % c. 28,6 %, p = 0,03) et un nombre moindre de comorbidités (66,7 % c. 21,4 %, p = 0,03), d'infections tardives (81,0 % c. 14,3 %, p = 0,01) et d'infections profondes (95,2 % c. 64,3 %, p = 0,03). Les implants sont demeurés en place chez 12 patients sur 16 (75,0 %) atteints d'infections précoces et chez 2 patients sur 19 (10,5 %) atteints d'infections tardives. Les patients chez qui l'implant a été retiré ont présenté un taux plus élevé de pseudarthrose (38,1 % c. 0 %, p = 0,02) et un taux de progression plus rapide de la courbure (5,8 ± 9,8 ° par année c. 0,2 ± 4,7 ° par année, p = 0,04). CONCLUSION: Il y a lieu d'envisager le maintien des implants, indépendamment du moment d'apparition de l'infection et de sa profondeur.

Outcomes of infection following pediatric spinal fusion.

BACKGROUND: Removal of instrumentation is often recommended as part of treatment for spinal infections, but studies have reported eradication of infection even with instrumentation retention by using serial débridements and adjuvant antibiotic pharmacotherapy. We sought to determine the effect of instrumentation retention or removal on outcomes in children with spinal infections. METHODS: We retrospectively reviewed the cases of patients who experienced early (< 3 mo) or late (≥ 3 mo) infected spinal fusions. Patients were evaluated at least 2 years after eradication of the infection using the following protocol outcomes: follow-up Cobb angle, curve progression and nonunion rates. RESULTS: Our sample included 35 patients. The mean age at surgery was 15.1 ± 6.0 years, 65.7% were girls, and mean follow-up was 41.7 ± 26.9 months. The mean Cobb angle was 63.6° ± 14.5° preoperatively, 29.4° ± 16.5° immediately after surgery and 37.2° ± 19.6° at follow-up. Patients in the implant removal group (n = 21) were more likely than those in the implant retention group (n = 14) to have a lower ASA score (71.4% v. 28.6%, p = 0.03), fewer comorbidities (66.7% v. 21.4%, p = 0.03), late infections (81.0% v. 14.3%, p = 0.01) and deep infections (95.2% v. 64.3%, p = 0.03). Implants were retained in 12 of 16 (75.0%) patients with early infections and 2 of 19 (10.5%) with late infections. Patients with implant removal had a higher pseudarthrosis rate (38.1% v. 0%, p = 0.02) and a faster curve progression rate (5.8 ± 9.8° per year v. 0.2 ± 4.7° per year, p = 0.04). CONCLUSION: Implant retention should be considered, irrespective of the timing or depth of the infection.

CONTEXTE: Le retrait des implants est souvent recommandé lors du traitement des infections rachidiennes, mais des études ont démontré qu'il est possible d'éliminer les infections tout en maintenant les implants en place, en ayant recours à des débridements répétés et à une antibiothérapie adjuvante. Nous avons voulu mesurer l'effet de la préservation ou du retrait des implants sur les résultats chez les enfants souffrant d'infections rachidiennes. MÉTHODES: Nous avons passé en revue de manière rétrospective des cas de fusions rachidiennes infectées à un stade précoce (< 3 mois) ou tardif (≥ 3 mois). Les patients ont été évalués au moins 2 ans après l'éradication de l'infection à l'aide des paramètres suivants : angle de Cobb, progression de la courbure et taux de non fusion au moment du suivi. RÉSULTANTS: Notre échantillon comprenait 35 patients. L'âge moyen au moment de la chirurgie était de 15,1 ± 6,0 ans; 65,7 % étaient des filles et le suivi moyen s'est échelonné sur 41,7 ± 26,9 mois. L'angle de Cobb moyen était de 63,6 ° ± 14,5 ° en période préopératoire, de 29,4 ° ± 16,5 ° immédiatement après la chirurgie et de 37,2 ° ± 19,6 ° au moment du suivi. Les patients du groupe soumis au retrait de l'implant (n = 21) étaient plus susceptibles que les patients du groupe chez qui l'implant est demeuré en place (n = 14) de présenter un score ASA plus bas (71,4 % c. 28,6 %, p = 0,03) et un nombre moindre de comorbidités (66,7 % c. 21,4 %, p = 0,03), d'infections tardives (81,0 % c. 14,3 %, p = 0,01) et d'infections profondes (95,2 % c. 64,3 %, p = 0,03). Les implants sont demeurés en place chez 12 patients sur 16 (75,0 %) atteints d'infections précoces et chez 2 patients sur 19 (10,5 %) atteints d'infections tardives. Les patients chez qui l'implant a été retiré ont présenté un taux plus élevé de pseudarthrose (38,1 % c. 0 %, p = 0,02) et un taux de progression plus rapide de la courbure (5,8 ± 9,8 ° par année c. 0,2 ± 4,7 ° par année, p = 0,04). CONCLUSION: Il y a lieu d'envisager le maintien des implants, indépendamment du moment d'apparition de l'infection et de sa profondeur.

Reoperations after tarsal coalition resection: a population-based study.

Few studies have evaluated the incidence of subsequent operations after tarsal coalition resection. Using administrative databases, we followed up a cohort of patients who had undergone tarsal coalition resection to determine the rates and possible risk factors for subsequent resection or arthrodesis. Patients (aged 8 years or older) who had been treated from July 1994 to August 2009 in Canada were identified and included. Those with nonidiopathic coalitions were excluded. The time-to-event data for the earliest subsequent procedure were fit to a Cox proportional hazards model that evaluated the patient, operative, and provider factors. Controlling for covariates, the hazard ratios were computed; however, the laterality of any subsequent operation could not be confirmed. A total of 304 patients underwent tarsal coalition resection at an average age of 24.2 ± 17.5 years. Of these 304 patients, 26 (8.6%) underwent subsequent resection and 16 (5.3%) mid- or hindfoot arthrodesis. Of all the factors, the need for future fusion was more likely only if the primary resection had been performed at an academic hospital or if the patient had undergone concomitant arthrodesis at primary resection of the coalition (hazard ratio 3.0, 95% confidence interval 1.1 to 8.5; and hazard ratio 9.7, 95% confidence interval 1.7 to 56.1, respectively). The incidence of reoperation after primary tarsal coalition resection was low in our cohort. More than 85% of our patients never required additional operative intervention an average of 9 years after the initial resection. Our data also suggest that primary treatment of tarsal coalition with resection and concomitant arthrodesis increases the risk of requiring a second fusion in the future.