Midterm Clinical and Radiographic Outcomes of the Calcaneal Z-Osteotomy for the Correction of Cavovarus Foot.

Background: The Malerba calcaneal Z-osteotomy is an operative procedure to treat the hindfoot varus component of adult cavovarus deformity. Basic science studies support the corrective ability of this osteotomy. However, there have been no published midterm clinical and radiographic results. The purpose of this article is to describe the radiographic and clinical improvement in a series of patients treated with this osteotomy. Methods: A retrospective chart review identified 14 feet in 12 patients from January 2013 to August 2018 who met minimal follow-up criteria. Preoperative visual analog scale (VAS) scores, Foot Function Index (FFI) scores, and American Orthopaedic Foot & Ankle Society (AOFAS) scores were compared with postoperative scores. Preoperative Meary angle, calcaneal pitch, and hindfoot alignment were also compared with postoperative measurements. Complications and radiographic union were recorded. Results: At a mean of 80 months, VAS, FFI, and AOFAS scores improved from 7.86 to 1.64, 57.78% to 18.11%, and 39.57 to 80.71, respectively (all P < .001). At a mean of 15 months, Meary angle, calcaneal pitch, and hindfoot alignment improved from 11.14 to 6.64 degrees (P < .001), 30.93 to 27.43 degrees (P = .005), and 19.83 degrees varus to 8.50 degrees varus (P < .001). There was 1 nonunion and 1 postoperative sural nerve neuralgia, but both patients ultimately did well clinically. There were no instances of postoperative tarsal tunnel syndrome. All patients stated that they would have the procedure done again. Conclusion: The calcaneal Z-osteotomy is an effective method to treat adult hindfoot cavovarus deformity. All patients had good clinical outcomes with minimal complications. Level of Evidence: Level IV, case series.

Bilateral Achilles Tendon Ruptures in the NFL.

Background: Achilles tendon ruptures (ATR) can have devastating results for athletes in the National Football League (NFL). While many studies have examined the effects of an ipsilateral ATR, there are no reports on the impact of bilateral ATRs on NFL athlete performance. Methods: Publicly available online injury data for NFL athletes who sustained bilateral ATRs between the start of the 2007 season and the start of the 2021 season were queried using online news and sports analysis web sources. Results: After applying inclusion and exclusion criteria, 5 NFL athletes were identified. The findings demonstrated a significant difference in age at the time of each rupture (27.8 vs 30.4 years, P < .01) along with a decreasing trend in the number of Pro Bowl nominations following successive ATRs (P = .027). There were no differences reported for the duration and number of games missed during either rehabilitation period following an ATR. Upon analyzing defensive NFL athletes, forced fumbles was the only performance metric that significantly changed across successive ATRs. Conclusion: Overall, bilateral ATRs can adversely impact an NFL player's performance and further research should be performed to continue analyzing the effects of bilateral ATRs on these athletes.Level of Evidence: 4.

Vitamin D Deficiency and Outcomes After Ankle Fusion: A Short Report.

BACKGROUND: Vitamin D deficiency has been postulated as a cause for impaired bone healing and remodeling. The purpose of this study was to assess the potential association between low vitamin D levels and reoperation for nonunion following ankle fusion surgery. METHODS: All adult patients (aged ≥18 years) who underwent ankle fusion procedures at a tertiary referral center from January 2010 to January 2019 with available vitamin D levels within 12 months preoperatively were retrospectively reviewed (n = 47). Patients were categorized as vitamin D deficient (<30 ng/mL) vs normal (31-80 ng/mL). The primary outcome was the incidence of reoperation secondary to nonunion. Secondary outcomes included incidence of reoperation not related to nonunion and the need for repeat reoperation. RESULTS: The average level in the vitamin D-deficient group (n = 17; 36.2%) was 16.9 vs 46.4 ng/mL in the normal group (n = 30; 63.8%). All recorded reoperations for nonunion occurred exclusively in the vitamin D-deficient cohort (4/17 [23.5%]; P = .013). There were similar reoperation rates for causes other than nonunion (2/17 [11.8%] vs 4/30 [13.3%]; P > .99) and repeat reoperation rates (3/17 [17.6%] vs 1/30 [3.3%]; P = .128) among vitamin D-deficient vs normal patients. CONCLUSION: Vitamin D deficiency may be associated with an increased risk of reoperation for nonunion after ankle fusion.

What Demographic and Clinical Factors Are Associated with In-hospital Mortality in Patients with Necrotizing Fasciitis?

BACKGROUND: Necrotizing fasciitis is a rare infection with rapid deterioration and a high mortality rate. Factors associated with in-hospital mortality have not been thoroughly evaluated. Although predictive models identifying the diagnosis of necrotizing fasciitis have been described (such as the Laboratory Risk Indicator for Necrotizing Fasciitis [LRINEC]), their use in predicting mortality is limited. QUESTIONS/PURPOSES: (1) What demographic factors are associated with in-hospital mortality in patients with necrotizing fasciitis? (2) What clinical factors are associated with in-hospital mortality? (3) What laboratory values are associated with in-hospital mortality? (4) Is the LRINEC score useful in predicting mortality? METHODS: We retrospectively studied all patients with necrotizing fasciitis at our tertiary care institution during a 10-year period. In all, 134 patients were identified; after filtering out patients with missing data (seven) and those without histologically confirmed necrotizing fasciitis (12), 115 patients remained. These patients were treated with early-initiation antibiotic therapy and aggressive surgical intervention once the diagnosis was suspected. Demographic data, clinical features, laboratory results, and treatment variables were identified. The median age was 56 years and 42% of patients were female. Of the 115 patients analyzed, 15% (17) died in the hospital. Univariate and receiver operating characteristic analyses were performed due to the low number of mortality events seen in this cohort. RESULTS: The demographic factors associated with in-hospital mortality were older age (median: 64 years for nonsurvivors [interquartile range (IQR) 57-79] versus 55 years for survivors [IQR 45-63]; p = 0.002), coronary artery disease (odds ratio 4.56 [95% confidence interval (CI) 1.51 to 14]; p = 0.008), chronic kidney disease (OR 4.92 [95% CI 1.62 to 15]; p = 0.006), and transfer from an outside hospital (OR 3.47 [95% CI 1.19 to 10]; p = 0.02). The presenting clinical characteristics associated with in-hospital mortality were positive initial blood culture results (OR 4.76 [95% CI 1.59 to 15]; p = 0.01), lactic acidosis (OR 4.33 [95% CI 1.42 to 16]; p = 0.02), and multiple organ dysfunction syndrome (OR 6.37 [95% CI 2.05 to 20]; p = 0.002). Laboratory values at initial presentation that were associated with in-hospital mortality were platelet count (difference of medians -136 [95% CI -203 to -70]; p < 0.001), serum pH (difference of medians -0.13 [95% CI -0.21 to -0.03]; p = 0.02), serum lactate (difference of medians 0.90 [95% CI 0.40 to 4.80]; p < 0.001), serum creatinine (difference of medians 1.93 [95% CI 0.65 to 3.44]; p < 0.001), partial thromboplastin time (difference of medians 8.30 [95% CI 1.85 to 13]; p = 0.03), and international normalized ratio (difference of medians 0.1 [95% CI 0.0 to 0.5]; p = 0.004). The LRINEC score was a poor predictor of mortality with an area under the receiver operating characteristics curve of 0.56 [95% CI 0.45-0.67]. CONCLUSIONS: Factors aiding clinical recognition of necrotizing fasciitis are not consistently helpful in predicting mortality of this infection. Identifying patients with potentially compromised organ function should lead to aggressive and expedited measures for diagnosis and treatment. Future multicenter studies with larger populations and a standardized algorithm of treatment triggered by high clinical suspicion can be used to validate these findings to better help prognosticate this potentially fatal diagnosis.Level of Evidence Level III, therapeutic study.

Are We Treating Similar Patients? Hospital Volume and the Difference in Patient Populations for Total Knee Arthroplasty.

BACKGROUND: Early findings of superior total knee arthroplasty (TKA) outcomes at high volume centers have been thought to have led to distinct referral patterns. However, the effect of these selective referral processes has not been well assessed. Therefore, this study compared the characteristics of primary TKA patients at high, intermediate, and low volume hospitals. METHODS: A total of 12,541 primary TKA patients were stratified into risk groups based on age (>65 years), body mass index (>40), and Charlson Comorbidity Index (≥4). Hospitals were classified as low, intermediate, or high volume based on mean annual TKA volumes (<250, 250-499, and >500). Multivariate logistic regression models evaluated the relationship between baseline patient characteristics and hospital volume. RESULTS: There was a greater percentage of high risk patients at high volume (19%, n = 853) compared to those at intermediate (16%, n = 899) or low volume (17%, n = 444) hospitals (P < .001). Patients with a body mass index >40 were more likely to be treated at high compared to intermediate (odds ratio [OR] 1.4, 95% confidence interval [CI] 1.2-1.6, P < .001) and low volume centers (OR 1.4, 95% CI 1.2-1.7, P < .001). Patients with Charlson Comorbidity Index scores ≥4 were also more likely be treated at high compared to intermediate (OR 1.5, 95% CI 1.3-1.6, P < .001) or low (OR 1.2, 95% CI 1.0-1.4, P = .002) volume centers. CONCLUSION: This study found that TKA patients at high volume centers have significantly different baseline characteristics compared to those at lower volume centers. This study highlights the importance of considering hospital volume status and the associated disparity in the preoperative risk of patients when comparing primary TKA outcomes between centers.

Remote Patient Monitoring Using Mobile Health for Total Knee Arthroplasty: Validation of a Wearable and Machine Learning-Based Surveillance Platform.

BACKGROUND: Recent technologic advances capable of measuring outcomes after total knee arthroplasty (TKA) are critical in quantifying value-based care. Traditionally accomplished through office assessments and surveys with variable follow-up, this strategy lacks continuous and complete data. The primary objective of this study was to validate the feasibility of a remote patient monitoring (RPM) system in terms of the frequency of data interruptions and patient acceptance. Second, we report pilot data for (1) mobility; (2) knee range of motion, (3) patient-reported outcome measures (PROMs); (4) opioid use; and (5) home exercise program (HEP) compliance. METHODS: A pilot cohort of 25 patients undergoing primary TKA for osteoarthritis was enrolled. Patients downloaded the RPM mobile application preoperatively to collect baseline activity and PROMs data, and the wearable knee sleeve was paired to the smartphone during admission. The following was collected up to 3 months postoperatively: mobility (step count), range of motion, PROMs, opioid consumption, and HEP compliance. Validation was determined by acquisition of continuous data and patient tolerance at semistructured interviews 3 months after operation. RESULTS: Of the 25 enrolled patients, 100% had uninterrupted passive data collection. Of the 22 available for follow-up interviews, all found the system motivating and engaging. Mean mobility returned to baseline within 6 weeks and exceeded preoperative baseline by 30% at 3 months. Mean knee flexion achieved was 119°, which did not differ from clinic measurements (P = .31). Mean KOOS improvement was 39.3 after 3 months (range: 3-60). Opioid use typically stopped by postoperative day 5. HEP compliance was 62% (range: 0%-99%). CONCLUSIONS: In this pilot study, we established the ability to remotely acquire continuous data for patients undergoing TKA, who found the application to be engaging. RPM offers the newfound ability to more completely evaluate the patients undergoing TKA in terms of mobility and rehabilitation compliance. Study with more patients is required to establish clinical significance.

Postoperative Infection in Cementless and Cemented Total Knee Arthroplasty: A Propensity Score Matched Analysis.

The ongoing debate on fixation in total knee arthroplasty (TKA) has become increasingly relevant with its increased use in a younger patient population and the advent of novel cementless prostheses. Recent literature suggests modern cementless implants are comparable to their cemented counterparts in terms of survivorship and functional outcomes. What has not been well-assessed is whether the two modalities differ with respect to infection rates which was the purpose of this study. Specifically, a propensity score matched study population was used to compare: (1) overall infection; (2) prosthetic joint infection (PJI); and (3) surgical site infection (SSI) rates between cementless and cemented TKAs. Using a large institutional database, 3,180 consecutive primary TKAs were identified. Cementless and cemented TKA patients were propensity score matched by age (p = 0.069), sex (p = 0.395), body mass index (BMI; p = 0.308), and Charlson's comorbidity index (CCI) score (p = 0.616) in a 1:1 ratio. Univariate analysis was performed to compare 2-year overall infection rates. Infections were further analyzed separately as PJIs (deep joint infections requiring surgery) and SSIs (skin/superficial wound infections). Multivariate logistic regression was performed to evaluate infection incidences after adjusting for procedure-related factors (i.e., operative time, hospital volume, and surgeon volume). There were no significant differences between the matched cohorts in terms of overall infection rates (3.8 vs. 2.3%, p = 0.722), as well as when PJI (p = 1.000) and SSI (p = 1.000) rates were analyzed separately. Multivariate analysis revealed no significant differences in overall postoperative infection rates (p = 0.285), PJI rates (p = 0.446), or SSI rates (p = 0.453) even after adjusting for procedure-related factors. There is increasing literature investigating various outcomes demonstrating the comparable efficacies of cementless versus cemented TKAs. To the best of the author's knowledge, this was the first matched case-control study to directly compare their post-operative infection rates. The findings from this study show that post-operative infection rates were similar between fixation modalities even after accounting for a range of patient- and procedure-related factors.

Optimizing the Volume-Value Relationship in Laminectomy: An Evidence-Based Analysis of Outcomes and Economies of Scale.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The objective of the present study was to establish evidence-based volume thresholds for surgeons and hospitals predictive of enhanced value in the setting of laminectomy. SUMMARY OF BACKGROUND DATA: Previous studies have attempted to characterize the relationship between volume and value; however, none to the authors' knowledge has employed an evidence-based approach to identify thresholds yielding enhanced value. METHODS: In total, 67,758 patients from the New York Statewide Planning and Research Cooperative System database undergoing laminectomy in the period 2009 to 2015 were included. We used stratum-specific likelihood ratio analysis of receiver operating characteristic curves to establish volume thresholds predictive of increased length of stay (LOS) and cost for surgeons and hospitals. RESULTS: Analysis of LOS by surgeon volume produced strata at: <17 (low), 17 to 40 (medium), 41 to 71 (high), and >71 (very high). Analysis of cost by surgeon volume produced strata at: <17 (low), 17 to 33 (medium), 34 to 86 (high), and >86 (very high). Analysis of LOS by hospital volume produced strata at: <43 (very low), 43 to 96 (low), 97 to 147 (medium), 148 to 172 (high), and >172 (very high). Analysis of cost by hospital volume produced strata at: <43 (very low), 43 to 82 (low), 83 to 115 (medium), 116 to 169 (high), and >169 (very high). LOS and cost decreased significantly (P < 0.05) in progressively higher volume categories for both surgeons and hospitals. For LOS, medium-volume surgeons handle the largest proportion of laminectomies (36%), whereas very high-volume hospitals handle the largest proportion (48%). CONCLUSION: This study supports a direct volume-value relationship for surgeons and hospitals in the setting of laminectomy. These findings provide target-estimated thresholds for which hospitals and surgeons may receive meaningful return on investment in our increasingly value-based system. Further value-based optimization is possible in the finding that while the highest volume hospitals handle the largest proportion of laminectomies, the highest volume surgeons do not. LEVEL OF EVIDENCE: 3.

Predictors of Extended Length of Hospital Stay in Adolescent Idiopathic Scoliosis Patients Undergoing Posterior Segmental Instrumented Fusion: An Analysis of 407 Surgeries Performed at a Large Academic Center.

STUDY DESIGN: Retrospective cohort study. OBJECTIVE: The aims of this study were to (1) compare patient and procedure-specific characteristics among those who had short versus long hospital stays and (2) identify independent risk factors that may correlate with extended length of hospital stay (LOS) in patients with adolescent idiopathic scoliosis (AIS) who underwent posterior segmental instrumented fusion (PSIF). SUMMARY OF BACKGROUND DATA: Reducing the LOS and identifying risk factors associated with extended admission have become increasingly relevant to healthcare policy makers. There is currently limited research identifying risk factors that correlate with extended stay in patients undergoing PSIF for AIS. METHODS: A single-institution, longitudinally maintained database was queried to identify 407 patients who met specific inclusion and exclusion criteria. Based on the distribution and median LOS in the cohort (4 days), patients were divided into those who had long versus short LOS. In both groups, patient demographics, comorbidities, preoperative scoliosis curve measurements, surgery-related characteristics, and complications were analyzed. A univariate and multivariate regression analysis was then conducted to identify independent risk factors associated with extended LOS. RESULTS: Patients who had extended LOS tended to be women (84.6% vs. 75%, P = 0.01), had more levels fused (9 ±â€Š2 vs. 7 ±â€Š2 levels, P < 0.001), had more major postoperative complications (0.8% vs. 7.4%, P = 0.002), had more blood loss during surgery (723 ±â€Š548 vs. 488 ±â€Š341 cm, P < 0.001), and received less epidural analgesia for pain control (69% vs. 89%, P < 0.001). Except for higher thoracic kyphosis, long LOS patients did not have worse preoperative radiographic curve parameters. Multivariate logistic analysis identified female sex, having ≥9 ±â€Š2 levels of fusion, operative blood loss, major postoperative complications, lack of epidural analgesia, and higher thoracic kyphosis as independent risk factors correlating for extended LOS. CONCLUSION: Independent risk factors identified by this study may be used to recognize patients with AIS at risk of prolonged hospital stay. LEVEL OF EVIDENCE: 3.

Validation of a New Web-Based System for Point-of-Care Implant Documentation in Total Knee Arthroplasty.

Implant documentation in total knee arthroplasty (TKA) must be both accurate and comprehensive. A new system enables surgeons to complete a secure, web-based operative report for each surgery. This study evaluated implant documentation using this system and hypothesized that it would be as reliable as the current standard. This was a retrospective study of all primary and revision TKA performed at a single academic institution from January 1, 2015 to March 31, 2015, by eight adult reconstruction surgeons who used the web-based system. Electronic medical records and implant logbooks were chosen as a composite standard reference for implant documentation. Cohen's kappa statistic and Pearson's correlation coefficients were used to determine agreement between the system and the standard reference. Mean kappa value for entire system was 0.916 ± 0.152 (p = 0.015) indicating "almost perfect" agreement (as per Landis and Koch's method) with standard reference. Pearson's correlation coefficient was 0.926 ± 0.147 (p = 0.021) further corroborating this excellent agreement. There was "substantial" or "fair" agreement for items pertaining to cement and augments. Overall, sensitivity was 0.98 (95% confidence interval: 0.71-0.98) and specificity 0.93 (95% confidence interval: 0.53-0.98) indicating that the system was very effective at documenting whether or not an implant was placed. The system exhibited significantly greater sensitivity than specificity (p = 0.027). This study demonstrated excellent performance of this novel system in point-of-care TKA implant documentation. Further research is needed to validate its use in arthroplasty of other joints and its potential for documentation of biomedical device implantation in other fields such as cardiothoracic surgery and gastroenterology.

The Diagnostic Utility of Synovial Fluid Markers in Periprosthetic Joint Infection: A Systematic Review and Meta-analysis.

INTRODUCTION: This study is a systematic review of all reported synovial fluid markers for the diagnosis of periprosthetic joint infection and a meta-analysis of the most frequently reported markers to identify those of greatest diagnostic utility. METHODS: A search of six databases was conducted to identify all studies evaluating the utility of synovial fluid markers in the diagnosis of periprosthetic joint infection. Two observers assessed methodologic quality and extracted data independently. A meta-analysis of the most frequently reported markers was performed. RESULTS: Twenty-three studies were included in the meta-analysis. The most common markers (and their respective area under the curve) were interleukin-17 (0.974), leukocyte esterase (0.968), α-defensin (0.958), interleukin-6 (0.956), interleukin-1ß (0.948), and C-reactive protein (0.927). Among these markers, α-defensin had the highest diagnostic odds ratio but did not achieve statistically significant superiority. CONCLUSION: The most frequently studied synovial fluid markers for the diagnosis of periprosthetic joint infection are C-reactive protein, leukocyte esterase, interleukin-6, interleukin-1ß, α-defensin, and interleukin-17, all of which have high diagnostic utility. LEVEL OF EVIDENCE: Level II.

The Use of Transcutaneous Electrical Nerve Stimulation After Total Knee Arthroplasty: A Prospective Randomized Controlled Trial.

INTRODUCTION: Multimodal pain management is used after total knee arthroplasty (TKA) to reduce opioid intake. Transcutaneous electrical nerve stimulation (TENS) has generated much interest as a non-pharmacologic, patient-controlled therapy. The aims of this study were to evaluate the efficacy of TENS in reducing opioid intake and improving recovery after TKA. MATERIALS AND METHODS: This was a prospective, parallel-group, double-blinded, randomized trial of patients receiving femoral nerve catheter block with allocation to either active or placebo TENS device groups. All participants were 18-85 years and underwent unilateral, primary TKA at two academic hospitals. Device usage was monitored during inpatient and outpatient phases. Participants were requested to return at second, fourth, and sixth postoperative weeks for follow-up. The primary endpoint was opioid usage, as indicated by medication intake in equianalgesic equivalents to morphine. Secondary measures included: visual analogue scale (VAS) pain scores; functional assessments as measured from knee joint range of motion (ROM) and Timed Up and Go (TUG) test; and clinical outcomes as defined by modified Knee injury and Osteoarthritis Outcome Scores (KOOS) and the 12-item Short Form Survey Instrument (SF-12). RESULTS: Among 116 participants, overall withdrawal was 37.9% (44 patients) at similar rates in both study arms. After excluding for non-femoral nerve catheter (FNC) blocks (i.e., protocol deviations), there were 35 patients in the active group and 31 patients in the placebo group whose complete records were analyzed. There were no significant differences between groups in any of the clinical endpoints.

Temporal Relations of Unplanned Readmissions Following Total Knee Arthroplasty: A Study of Large State Inpatient Databases.

BACKGROUND: Centers for Medicare & Medicaid Services stipulate a 90-day global period for hospitals for unplanned readmissions after primary total knee arthroplasty (TKA). However, not all readmissions are directly attributable to index surgery, and reasons for readmissions vary during this time period. This study identifies causes and temporal relations of readmissions using large state inpatient databases. METHODS: State inpatient databases of New York and California were queried for all primary TKAs performed from 2005 to 2011 and frequencies of all causes of unplanned readmission were identified from 0 to 90 days after index surgery using the International Classification of Diseases, Ninth Revision, codes. Temporal differences in proportions of readmission diagnoses were tested using the Pearson chi-square test. RESULTS: The query identified 419,805 cases of primary TKA from 2005 to 2011. There were 26,924 readmissions during the 90-day recovery period, with 15,547 (57.7%) at 0-30 days, 6593 (24.5%) at 31-60 days, and 4784 (17.8%) at 61-90 days. Primary diagnoses at readmission that were identified to be directly attributable to surgery comprised 38.3% readmissions at 0-30 days, 24.0% at 31-60 days, and 16.3% at 60-90 days. Proportion of readmissions directly attributable to surgery decreased over the 90-day period after index surgery. CONCLUSION: From this analysis of 2 large state inpatient databases, primary diagnoses at readmission vary with time, and majority of these may not be directly attributable to index surgery or postoperative state up to 90 days. These findings suggest that the current 90-day global period policy for this procedure should be reformed to better reflect the profile of unplanned readmissions after TKA.

Administrative Databases Can Yield False Conclusions-An Example of Obesity in Total Joint Arthroplasty.

BACKGROUND: Research using large administrative databases has substantially increased in recent years. Accuracy with which comorbidities are represented in these databases has been questioned. The purpose of this study was to evaluate the extent of errors in obesity coding and its impact on arthroplasty research. METHODS: Eighteen thousand thirty primary total knee arthroplasties (TKAs) and 10,475 total hip arthroplasties (THAs) performed at a single healthcare system from 2004-2014 were included. Patients were classified as obese or nonobese using 2 methods: (1) body mass index (BMI) ≥30 kg/m2 and (2) international classification of disease, 9th edition codes. Length of stay, operative time, and 90-day complications were collected. Effect of obesity on various outcomes was analyzed separately for both BMI- and coding-based obesity. RESULTS: From 2004 to 2014, the prevalence of BMI-based obesity increased from 54% to 63% and 40% to 45% in TKA and THA, respectively. The prevalence of coding-based obesity increased from 15% to 28% and 8% to 17% in TKA and THA, respectively. Coding overestimated the growth of obesity in TKA and THA by 5.6 and 8.4 times, respectively. When obesity was defined by coding, obesity was falsely shown to be a significant risk factor for deep vein thrombosis (TKA), pulmonary embolism (THA), and longer hospital stay (TKA and THA). CONCLUSION: The growth in obesity observed in administrative databases may be an artifact because of improvements in coding over the years. Obesity defined by coding can overestimate the actual effect of obesity on complications after arthroplasty. Therefore, studies using large databases should be interpreted with caution, especially when variables prone to coding errors are involved.

Predictors of Staphylococcus aureus Colonization and Results after Decolonization.

Protocols for the screening and decolonization of Staphylococcus aureus prior to total joint arthroplasty (TJA) have become widely adopted. The goals of this study were to determine: (1) whether implementation of a screening protocol followed by decolonization with mupirocin/vancomycin and chlorhexidine reduces the risk of revision compared with no screening protocol (i.e., chlorhexidine alone) and (2) whether clinical criteria could reliably predict colonization with MSSA and/or MRSA. Electronic medical records of primary patients undergoing TJA that were screened (n = 3,927) and were not screened (n = 1,751) for Staphylococcus aureus at least 4 days prior to surgery, respectively, were retrospectively reviewed. All patients received chlorhexidine body wipes preoperatively. Patients carrying MSSA and MRSA were treated preoperatively with mupirocin and vancomycin, respectively, along with the standard preoperative antibiotics and chlorhexidine body wipes. Screened patients were 50% less likely to require revision due to prosthetic joint infection compared to those not screened (p = 0.04). Multivariate regression models were poorly accurate in predicting colonization with MSSA (AUC = 0.58) and MRSA (AUC = 0.62). These results support the routine screening and decolonization of S. aureus prior to TJA.

Role of negative pressure wound therapy in total hip and knee arthroplasty.

Negative-pressure wound therapy (NPWT) has been a successful modality of wound management which is in widespread use in several surgical fields. The main mechanisms of action thought to play a role in enhancing wound healing and preventing surgical site infection are macrodeformation and microdeformation of the wound bed, fluid removal, and stabilization of the wound environment. Due to the devastating consequences of infection in the setting of joint arthroplasty, there has been some interest in the use of NPWT following total hip arthroplasty and total knee arthroplasty. However, there is still a scarcity of data reporting on the use of NPWT within this field and most studies are limited by small sample sizes, high variability of clinical settings and end-points. There is little evidence to support the use of NPWT as an adjunctive treatment for surgical wound drainage, and for this reason surgical intervention should not be delayed when indicated. The prophylactic use of NPWT after arthroplasty in patients that are at high risk for postoperative wound drainage appears to have the strongest clinical evidence. Several clinical trials including single-use NPWT devices for this purpose are currently in progress and this may soon be incorporated in clinical guidelines as a mean to prevent periprosthetic joint infections.

Irrigation and Debridement Before a 2-Stage Revision Total Knee Arthroplasty Does Not Increase Risk of Failure.

BACKGROUND: Studies have suggested that the success of 2-stage revision total knee arthroplasty (rTKA) may be compromised by a prior failed irrigation and debridement (I&D). The purpose of this study was to use 2 large state inpatient databases to compare the 2-stage rTKA failure rates for those patients with and without a prior I&D. METHODS: This retrospective, longitudinal study used inpatient discharge data from the State Inpatient Database of 2 states (California and New York) from 2005 to 2011. A combination of International Classification of Diseases, Ninth Revision, diagnosis and procedure codes was used to identify rTKA patients and compare failure rates for rTKA patients with and without prior I&D. The primary outcome was failure of the staged revision, which was defined as subsequent surgery due to infection within 4 years of the 2-stage rTKA. RESULTS: Of the 750 patients who underwent 2-stage rTKA, 57 had undergone a prior I&D. In all, 126 patients failed rTKA. After 4 years, the estimated failure rate was 8.7% (95% confidence interval [CI], 1.9%-16.9%) in the group with prior I&D and 17.5% (95% CI, 14.7%-20.4%) in the group without prior I&D. After adjusting for sex, race, insurance, median household income, and comorbidities, the hazard ratio for the group with a failed I&D was 0.49 (P = .122; 95% CI, 0.20-1.20), which indicated a lower risk of failure compared to the group without prior I&D. CONCLUSION: These findings indicate that the failure rate of 2-stage rTKA is not increased by prior failed I&D.

Are Frozen Sections and MSIS Criteria Reliable at the Time of Reimplantation of Two-stage Revision Arthroplasty?

BACKGROUND: Frozen section histology is widely used to aid in the diagnosis of periprosthetic joint infection at the second stage of revision arthroplasty, although there are limited data regarding its utility. Moreover, there is no definitive method to assess control of infection at the time of reimplantation. Because failure of a two-stage revision can have serious consequences, it is important to identify the cases that might fail and defer reimplantation if necessary. Thus, a reliable test providing information about the control of infection and risk of subsequent failure is necessary. QUESTIONS/PURPOSES: (1) At second-stage reimplantation surgery, what is the diagnostic accuracy of frozen sections as compared with the Musculoskeletal Infection Society (MSIS) as the gold standard? (2) What are the diagnostic accuracy parameters for the MSIS criteria and frozen sections in predicting failure of reimplantation? (3) Do positive MSIS criteria or frozen section at the time of reimplantation increase the risk of subsequent failure? METHODS: A total of 97 patients undergoing the second stage of revision total hip arthroplasty or total knee arthroplasty in 2013 for a diagnosis of periprosthetic joint infection (PJI) were considered eligible for the study. Of these, 11 had incomplete MSIS criteria and seven lacked 1-year followup, leaving 79 patients (38 knees and 41 hips) available for analysis. At the time of reimplantation, frozen section results were compared with modified MSIS criteria as the gold standard in detecting infection. Subsequently, success or failure of reimplantation was defined by (1) control of infection, as characterized by a healed wound without fistula, drainage, or pain; (2) no subsequent surgical intervention for infection after reimplantation surgery; and (3) no occurrence of PJI-related mortality; and diagnostic parameters in predicting treatment failure were calculated for both the modified MSIS criteria and frozen sections. RESULTS: At the time of second-stage reimplantation surgery, frozen section is useful in ruling in infection, where the specificity is 94% (95% confidence interval [CI], 89%-99%); however, there is less utility in ruling out infection, because sensitivity is only 50% (CI, 13%-88%). Both the MSIS criteria and frozen sections have high specificity for ruling in failure of reimplantation (MSIS criteria specificity: 96% [CI, 91%-100%]; frozen section: 95% [CI, 88%-100%]), but screening capabilities are limited (MSIS sensitivity: 26% [CI, 9%-44%]; frozen section: 22% [CI, 9%-29%]). Positive MSIS criteria at the time of reimplantation were a risk factor for subsequent failure (hazard ratio [HR], 5.22 [1.64-16.62], p = 0.005), whereas positive frozen section was not (HR, 1.16 [0.15-8.86], p = 0.883). CONCLUSIONS: On the basis of our results, both frozen section and MSIS are recommended at the time of the second stage of revision arthroplasty. Both frozen section and modified MSIS criteria had limited screening capabilities to identify failure, although both demonstrated high specificity. MSIS criteria should be evaluated at the second stage of revision arthroplasty because performing reimplantation in a joint that is positive for infection significantly increases the risk for subsequent failure. LEVEL OF EVIDENCE: Level III, diagnostic study.

Current concepts in total femoral replacement.

Total femoral replacement (TFR) is a salvage arthroplasty procedure used as an alternative to lower limb amputation. Since its initial description in the mid-20(th) century, this procedure has been used in a variety of oncologic and non-oncologic indications. The most compelling advantage of TFR is the achievement of immediate fixation which permits early mobilization. It is anticipated that TFR will be increasingly performed as the rate of revision arthroplasty rises worldwide. The existing literature is mainly composed of a rather heterogeneous mix of retrospective case series and a wide assortment of case reports. Numerous TFR prostheses are currently available and the surgeon must understand the unique implications of each implant design. Long-term functional outcomes are dependent on adherence to proper technique and an appropriate physical therapy program for postoperative rehabilitation. Revision TFR is mainly performed for periprosthetic infection and the severe femoral bone loss associated with aseptic revisions. Depending on the likelihood of attaining infection clearance, it may sometimes be advisable to proceed directly to hip disarticulation without attempting salvage of the TFR. Other reported complications of TFR include hip joint instability, limb length discrepancy, device failure, component loosening, patellar maltracking and delayed wound healing. Further research is needed to better characterize the long-term functional outcomes and complications associated with this complex procedure.