Use of The Risk Assessment and Prediction Tool to Predict Same-day Discharge After Primary Hip and Knee Arthroplasty.

INTRODUCTION: The Risk Assessment and Prediction Tool (RAPT) is a preoperative screening tool developed to predict discharge disposition after total hip arthroplasty (THA) and total knee arthroplasty (TKA), but its predictive value for same-day discharge (SDD) has not been investigated. The aims of this study were (1) to assess RAPT's ability to predict SDD after primary THA and TKA and (2) to determine a cutoff RAPT score that may recognize patients appropriate for SDD. METHODS: Data were retrospectively collected from patients undergoing primary THA and TKA at a single tertiary care center between February 2020 and May 2021. A receiver operating characteristic curve was generated to choose a cutoff value to screen for SDD. Logistic regression analysis was done to identify factors including age, BMI, or RAPT score that may be associated with SDD. RESULTS: Three hundred sixty-one patients with preoperative RAPT scores were included in the analysis of whom 147 (42.6%) underwent SDD. A cutoff of ≥9 was identified for TKA and ≥11 for THA. RAPT had a predictive accuracy of only 66.7% for SDD, whereas the discharge plan documented in the preoperative note was 91.7% accurate. DISCUSSION: Although there is a positive association between RAPT and SDD, it is not a useful screening tool given its low predictive accuracy.

Is There an Implicit Racial Bias in the Case Order of Elective Total Joint Arthroplasty?

INTRODUCTION: Identifying ways to improve equitable access to healthcare is of the utmost important. In this study, we analyzed whether patient race was negatively associated with surgical start times for total joint arthroplasties (TJA). METHODS: The surgical case order and start times of all primary TJAs performed at a large academic medical center between May 2014 and May 2018 were retrospectively reviewed. Patients were included if > 21, had a documented self-reported race, and were operated on by an arthroplasty fellowship-trained surgeon. Operations were categorized as first-start, early (7:00 AM-11:00 AM), mid-day (11:00 AM-3:00 PM), or late (after 3:00 PM). Multivariable logistic regression (MLR) was performed, and odds ratios (OR) were calculated. RESULTS: This study identified 1663 TJAs-871 total knee (TKA) and 792 total hip arthroplasties (THA) who met inclusion criteria. Overall, there was no association between race and surgical start time. Upon sub-analysis by surgical type, this held true for TKA patients, but self-identifying Hispanic and non-Hispanic Black patients undergoing THA were more likely to have later surgical start times (ORs: 2.08 and 1.88; p < 0.05). DISCUSSION: Although there was no association between race and overall TJA surgical start times, patients with marginalized racial and ethnic identities were more likely to undergo elective THA later in the surgical day. Surgeons should be aware of potential implicit bias when determining case order to potentially prevent adverse outcomes due to staff fatigue or lack of proper resources later in the day.

Patient-reported outcomes measurement information system instruments in knee arthroplasty patients: a systematic review of the literature.

BACKGROUND: The purpose of this study is to provide a systematic review of the literature pertaining to Patient-Reported Outcome Measurement Information System (PROMIS) validation and utilization as an outcomes metric in total knee arthroplasty (TKA) patients. This is the first systematic review on PROMIS use in total knee arthroplasty patients. METHODS: A systematic search of the Pubmed/MEDLINE and Embase databases was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Study characteristics, patient demographics, psychometric properties (Pearson and Spearman correlation) with legacy patient-reported outcome measurement (PROM) instruments, floor and ceiling effects, responsiveness, and minimum clinically important difference (MCID) and PROMIS outcomes were recorded and analyzed. RESULTS: Fifteen studies investigating PROMIS in 11,140 patients were included. The weighted-average Pearson correlation coefficient comparing PROMIS domains with legacy patient-reported outcome measurements in total knee arthroplasty patients was 0.62 [standard error (SE) = 0.06] and the weighted-average Spearman correlation comparing PROMIS domains with legacy patient-reported outcome measurements in total knee arthroplasty patients was 0.59 (SE = 0.06), demonstrating moderate-to-strong correlation and validity. There were no differences in weighted average floor [0.03% (SE = 3.1) versus 0% (SE = 0.1) versus 0.01% (SE = 1.1); p = 0.25] or ceiling effects [0.01% (SE = 0.7) versus 0.02% (SE = 1.4) versus 0.04% (SE = 3.5); p = 0.36] between PROMIS and legacy instruments. The weighted average for percentage of patients achieving MCID was 59.1% for global physical health (GPH), 26.0% for global mental health (GMH), 52.7% for physical function (PF), 67.2% for pain interference (PI), and 37.2% for depression. CONCLUSION: Notably, PROMIS global physical health, physical function, and pain interference were found to be significantly responsive, with PROMIS pain interference most effectively capturing clinical improvement as evidenced by the achievement of MCID.

Machine Learning Model Developed to Aid in Patient Selection for Outpatient Total Joint Arthroplasty.

BACKGROUND: Patient selection for outpatient total joint arthroplasty (TJA) is important for optimizing patient outcomes. This study develops machine learning models that may aid in patient selection for outpatient TJA based on medical comorbidities and demographic factors. METHODS: This study queried elective total knee arthroplasty (TKA) and total hip arthroplasty (THA) cases during 2010-2018 in the American College of Surgeons National Surgical Quality Improvement Program. Artificial neural network models predicted same-day discharge and length of stay (LOS) fewer than 2 days (short LOS). Multiple linear and logistic regression analyses were used to identify variables significantly associated with predicted outcomes. RESULTS: A total of 284,731 TKA cases and 153,053 THA cases met inclusion criteria. For TKA, prediction of short LOS had an area under the receiver operating characteristic curve (AUC) of 0.767 and accuracy of 84.1%; prediction of same-day discharge had an AUC of 0.802 and accuracy of 89.2%. For THA, prediction of short LOS had an AUC of 0.757 and accuracy of 70.6%; prediction of same-day discharge had an AUC of 0.814 and accuracy of 78.8%. CONCLUSION: This study developed machine learning models for aiding patient selection for outpatient TJA, through accurately predicting short LOS or outpatient vs inpatient cases. As outpatient TJA expands, it will be important to optimize preoperative patient selection and effectively screen surgical candidates from a broader patient population. Incorporating models such as these into electronic medical records could aid in decision-making and resource planning in real time.

Intraoperative Scrub Nurse Handoffs Are Associated with Increased Operative Times for Lower Extremity Orthopaedic Sports Procedures.

PURPOSE: The purpose of this study was to evaluate the effect of intraoperative scrub nurse handoffs on surgical times for arthroscopically-assisted anterior cruciate ligament (ACL) reconstructions and hip arthroscopies. METHODS: A retrospective chart review was done at a major, urban academic medical center for all patients who underwent arthroscopically-assisted ACL reconstructions and hip arthroscopies for femoroacetabular impingement syndrome between May 2014 and May 2020. All ACL reconstructions were performed by 1 of 6 sports medicine fellowship-trained surgeons, and all hip arthroscopies were performed by a single surgeon. Operative times, number of scrub nurse handoffs, surgeon, patient demographics, and procedure-specific information were recorded. The association between patient characteristics and the number of handoffs, as well as the association between patient characteristics and operative times, stratified by scrub nurse handoffs, were calculated. A multivariable linear regression was performed to assess the association between intra-operative handoffs and operative times. RESULTS: Eight hundred twenty ACL reconstructions and 269 hip arthroscopies were identified. Multivariable linear regression demonstrated increasing intraoperative scrub nurse handoffs were associated with increased operative times for all patients. For ACL reconstructions, when including all possible covariates, 1 scrub nurse handoff increased operative times by 21.1 minutes (95% confidence interval [CI]: 15.36 to 26.89; P < .001), and 2+ handoffs increased operative times by 34.2 minutes (95% CI: 26.28 to 42.15; P < .001). For hip arthroscopies, 1 scrub nurse handoff increased operative times by 7.0 minutes (95% CI: 0.31 to 13.74; P = .04). CONCLUSION: Although a causal link cannot be made, intraoperative scrub nurse handoffs were associated with statistically significant increase in operative times for both ACL reconstructions and hip arthroscopies. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

Intraoperative Scrub Nurse Handoffs Are Associated With Increased Operative Times for Total Joint Arthroplasty Patients.

BACKGROUND: Surgeons typically remain scrubbed in for the duration of a surgical case, while scrub nurses are shift-workers who handoff mid-operation. These handoffs can intuitively create inefficiencies, but currently, no orthopedic research has studied the impact of these handoffs. This study analyzed the effect of intraoperative scrub nurse handoffs on operative times for total joint arthroplasties (TJAs). METHODS: A retrospective chart review was performed for primary total hip (THA) and total knee arthroplasties (TKA) performed between May 2014 and May 2018. Operative times, number of scrub nurse handoffs, surgeon, and patient information were collected. A multivariable linear regression was performed to assess the association between patient and surgeon characteristics, intraoperative handoffs, and operative times. RESULTS: A total of 1109 TKA and 1032 THA patients were identified. Multivariable linear regression demonstrated that for TKAs, 1 handoff was associated with a 3.89-minute longer operative time (P value = .02), and 2+ handoffs were associated with a 15.99-minute longer case (P value < .001). For THA patients, 1 handoff was associated with a 6.20-minute longer operative time (P value < .001), and 2+ handoffs were associated with an 18.52-minute longer case (P value < .001). CONCLUSIONS: Although causation cannot be established, when controlling for multiple confounders, intraoperative scrub nurse handoffs were associated with statistically significant increases in operative times for TJAs. Optimizing scrub nurse staffing models to decrease intraoperative handoffs could thus have practical ramifications on TJA patients.

State Medical Cannabis Laws Associated With Reduction in Opioid Prescriptions by Orthopaedic Surgeons in Medicare Part D Cohort.

INTRODUCTION: Opioid prescriptions and abuse remain a significant national concern. Cannabinoids offer a potentially attractive nonopioid analgesic option for orthopaedic patients, and 32 US states have passed medical cannabis laws (MCLs), legalizing patient access to cannabinoids. We examine the association between implementation of state cannabis laws and prescribing patterns for opioids by orthopaedic surgeons in Medicare Part D patients between 2013 and 2017. METHODS: Using the Medicare Part D Prescription Drug Event database, we measured annual aggregate daily doses of all opioid medications (excluding buprenorphine) prescribed by orthopaedic surgeons in each US state (and DC), in addition to total daily doses of opioid medications by generic name (hydrocodone, oxycodone, fentanyl, morphine, methadone, and "other opioids"). We used adjusted linear regression models to examine associations between state-specific cannabis regulations (state MCL, MCL type-dispensary or home cultivation, and recreational cannabis legalization) and annual total daily doses of opioid medications (all opioids and opioid types, separately). RESULTS: State MCLs were associated with a statistically significant reduction in aggregate opioid prescribing of 144,000 daily doses (19.7% reduction) annually (95% confidence interval [CI], -0.535 to -0.024 million; P < 0.01). States with MCLs allowing access to in-state dispensaries had a statistically significant reduction in total opioid prescriptions of 96,000 daily doses (13.1%) annually (95% CI, -0.165 to -0.026 million; P < 0.01). Specifically, MCLs were associated with a statistically significant reduction of 72,000 daily doses of hydrocodone annually (95% CI, -0.164 to -0.019 million; P < 0.01). No significant association between recreational marijuana legalization and opioid prescribing was found. CONCLUSION: Orthopaedic surgeons are among the highest prescribers of opioids, highlighting the importance of providing nonopioid analgesic alternatives in efforts to reduce opioid use in the patient cohort. This study is the first to examine the association between implementation of state cannabis laws and prescribing patterns for opioids by orthopaedic surgeons in Medicare Part D patients. LEVEL OF EVIDENCE: Population-based ecological study.

What Is the Learning Curve for New Technologies in Total Joint Arthroplasty? A Review.

PURPOSE OF REVIEW: The adaptation of new technology in joint replacement surgery is often associated with a learning curve, as performance tends to improve with experience. The purpose of this review is to define the learning curve and its relevance to joint replacement surgery in the setting of new technological advances, and to draw analogies with the learning curve of basic surgical training. RECENT FINDINGS: Assessing a surgeon's learning curve for a new technology is complicated and difficult. With every learning curve, the first patients subjected to the novel technology may be at higher risk for adverse events until the learning curve is overcome and a steady state is reached. While measures of performance can be clear and direct in some professions, learning curves with new technology in total joint arthroplasty have been difficult to quantify. Most attempts measure surgical learning curves via an evaluation of the surgical process or patient outcomes. There are published results of both process (i.e., operative time, accuracy of implant position) and outcome measures (i.e., complication rate, revision rate) utilized as proxy for performance during learning curves. We review the concept of the learning curve in joint replacement surgery, highlighting examples of learning curves with adaptation of new technologies, and conclude with a discussion of dilemmas and challenges.

Opioid Prescription Consumption Patterns After Total Joint Arthroplasty in Chronic Opioid Users Versus Opioid Naive Patients.

Although chronic preoperative opioid use has been linked to inferior total joint arthroplasty outcomes, little research exists on postoperative prescribing patterns for opioid-naive orthopaedic patients versus chronic opioid users. Method: The New York State Prescription Monitoring Program database, which tracks controlled prescriptions dispensed in-state over the preceding 12 months, was retrospectively queried for 386 patients who underwent primary, elective total hip or knee arthroplasty at a high-volume, urban medical center from May through December 2017. Seventy-four patients were excluded because they did not return prescription monitoring program results, leaving 312 patients. Prescribers, medications, dates prescribed and filled, and quantity dispensed were recorded 3 months preoperatively through 12 months postoperatively. We defined chronic users as ≥2 opioid prescriptions filled in 3 preoperative months and opioid-naive as <2 filled. Opioid use was compared univariately using 2-tailed Student t-tests. Results: Chronic opioid users (n = 49; 15.7%) filled an average of 13,006.64 morphine equivalent doses per patient in the 12-month postoperative period, while opioid-naive users (n = 263; 84.3%) filled an average of 854.48 morphine equivalent doses per patient (P < 0.01). Opioid use in the chronic-user group was significantly higher in each 6-week postoperative interval (P < 0.01). These trends remained significant when stratified by procedure. For opioid-naive patients, 74% of opioid prescriptions were prescribed by our orthopaedic department. For chronic users, only 21% of opioid prescriptions originated from our department. Chronic users were found to cyclically fill opioid prescriptions every 3 to 4 weeks postoperatively as far out as 12 months and were significantly more likely to fill nonopioid controlled substance prescriptions both preoperatively and postoperatively (P < 0.01). Discussion: Chronic opioid users undergoing arthroplasty filled significantly more opioid prescriptions than opioid-naive patients. Chronic users obtained prescriptions from myriad sources, only a minority of which originated from our orthopaedic department. In the current opioid epidemic, vigilance regarding opioid prescribing is critical.

Deeper Central Reaming May Enhance Initial Acetabular Shell Fixation.

BACKGROUND: The initial stability of press-fit acetabular components is partially determined by the reaming technique. Nonhemispherical (NHS) acetabular shells, which have a larger radius at the rim than the dome, often require larger reaming preparations than the same-sized hemispherical (HS) shells. Furthermore, deeper central reaming may provide a more stable press fit. Using a reproducible, in vitro protocol, we compared initial shell stability under different reaming techniques with HS and NHS acetabular components. METHODS: Cavities for 54-mm NHS and 56-mm HS acetabular components were premachined in 20-pcf Sawbones blocks. Acetabular cavities included diameters of 54, 55, "54+," and "55+". "+" indicates a cavity with a 2-mm smaller diameter that is 2-mm deeper. A 4750N statically applied force seated shells to a height that was comparable with shell height after an orthopaedic surgeon's manual impaction. Force required to dislodge shells was assessed via a straight torque-out with a linear load. RESULTS: Increased preparation depth (+) was associated with deeper shell seating in all groups. Deeper central reaming increased required lever-out force for all groups. Overall, HS and NHS implants prepared with 55 + preparation had the highest lever-out forces, although this was not significantly higher than those with 54+. CONCLUSIONS: In 20-pcf Sawbones, representing dense bone, overreaming depth by 1-mm improved initial seating measurements. In both HS and NHS acetabular shells, seating depth and required lever-out force were higher in the "+" category. It is unclear, however, whether a decreased diameter ream increased seating stability (55+ vs 54+). Clinically, this deeper central reaming technique may help initial acetabular stability.

Preemptive Analgesia With Oxycodone Is Associated With More Pain Following Total Joint Arthroplasty.

BACKGROUND: Preemptive multimodal analgesia (PMA) is a commonly used technique to control pain following total joint arthroplasty. PMA protocols use multiple analgesics immediately preoperatively to prevent central sensitization and amplification of pain during surgery. While benefits of some individual components of a PMA protocol have been established, there are little data to support inclusion or exclusion of opioids in this context. METHODS: This is a retrospective cohort study of 550 patients undergoing elective, primary total joint arthroplasty at a single institution using a standardized preoperative perioperative protocol. Two hundred seventy-five patients received oxycodone in addition to a standard multimodal preoperative analgesia regimen just before surgery and were compared to a matched cohort of 275 patients who received the standard regimen alone. Outcome measures included inpatient visual analog scale pain scores, inpatient opioid consumption, length of stay, and ambulation distance with physical therapy. RESULTS: Patients who received opioids in preoperative holding reported significantly greater visual analog scale pain scores on postoperative day 1 (3.7 vs 3.1; P = .01), when compared to those who did not. These patients also walked shorter distances on postoperative day 0 (59.5' vs 125.7'; P < .001) and consumed greater morphine equivalents per hospital day over the course of their hospital stay (52.2 vs 37.2 mg; P < .001). These differences remained significant when stratified by procedure, total knee arthroplasty or total hip arthroplasty. Differences in pain and function between groups were more pronounced in patients undergoing total hip arthroplasty than those undergoing total knee arthroplasty. CONCLUSION: Total joint patients who were given preemptive opioids immediately before surgery experienced more pain, consumed more postoperative opioids, and exhibited impaired early function as compared to those who were not given preemptive opioids. Orthopedic surgeons should reconsider routine use of preemptive opioids in this context.

Should Cannabinoids Be Added to Multimodal Pain Regimens After Total Hip and Knee Arthroplasty?

BACKGROUND: This study investigated the effects of dronabinol on pain, nausea, and length of stay following total joint arthroplasty (TJA). METHODS: We retrospectively compared 81 consecutive primary TJA patients who received 5 mg of dronabinol twice daily in addition to a standard multimodal pain regimen with a matched cohort of 162 TJA patients who received only the standard regimen. A single surgeon performed all surgeries. Patient demographics, length of stay, opioid morphine equivalents (MEs) consumed, reports of nausea/vomiting, discharge destination, distance walked in physical therapy, and visual analog scale pain scores were collected for both groups. Student's t-tests as well as chi-square or Mann-Whitney U-tests were used for statistical comparisons. RESULTS: There were no significant differences between the 2 groups for age, gender, body mass index, American Society of Anesthesiologists score, anesthesia type, visual analog scale scores, distance walked with physical therapy, discharge disposition, or episodes of nausea/vomiting. The mean length of stay in the dronabinol group was significantly shorter at 2.3 ± 0.9 days versus 3.0 ± 1.2 days in the control group (P = .02). In the context of a shorter stay, the dronabinol group consumed significantly fewer total MEs (252.5 ± 131.5 vs 313.3 ± 185.4 mg, P = .0088). Although the dronabinol group consumed fewer MEs per day and per length of stay on average, neither of these achieved statistical significance. No side effects of dronabinol were reported. CONCLUSION: These findings suggest that further investigation into the role of cannabinoid medications for non-opioid pain control in the post-arthroplasty patient may hold merit.

Risk factors for conversion surgery to total hip arthroplasty of a hemiarthroplasty performed for a femoral neck fracture.

INTRODUCTION: The purpose of this study was to determine risk factors for conversion to total hip arthroplasty (THA) in patients originally treated with hemiarthroplasty (HA) for displaced femoral neck fractures. METHODS: In this case-controlled study, we identified 54 patients who were treated with HA for femoral neck fracture (FNF) who subsequently underwent conversion to THA at our institution between 2003 and 2013. We randomly selected 142 control patients who underwent HA for a displaced FNF without conversion surgery during the same time period. We compared demographic data, implant parameters, and radiographic data between the groups to identify risk factors for conversion surgery. RESULTS: In the univariate analysis, younger age at index surgery (mean 75 vs. 80 years, p = 0.006), higher body mass index (26.1 vs. 23.7, p = 0.031), bipolar prosthesis (20% vs. 36%, p = 0.024), absence of dementia (6% vs. 23%, p = 0.01), increased leg length compared to contralateral limb (6.5 mm vs. 0.2 mm, p<0.001), and increased HA femoral head size compared to the contralateral femoral head (2.7 mm vs. 1.5 mm, p = 0.02) were associated with a significantly increased risk of conversion surgery. In the multivariate logistic regression, decreased age at index surgery, no dementia, use of a bipolar head, and increased leg length discrepancy (LLD) were associated with risk of conversion. CONCLUSIONS: Patient characteristics, including younger age, increased BMI, and absence of dementia can lead to increased risk for conversion of HA to THA. Intraoperative considerations of head size and increase in ipsilateral LLD may increase the risk of conversion surgery. These factors should be considered by surgeons who employ HA for displaced FNFs.

Tranexamic acid increases early perioperative functional outcomes after total knee arthroplasty.

BACKGROUND: The purpose of this study was to investigate the influence of tranexamic acid (TXA) on functional outcomes in the immediate postoperative period after total knee arthroplasty (TKA). We hypothesized that the known benefits of TXA would confer measurable clinical improvements in physical therapy (PT) performance, decrease pain, and decrease hospital length of stay (LOS). METHODS: We retrospectively analyzed 560 TKA patients, including 280 consecutive patients whose surgery was performed before the initiation of a standardized TXA protocol and the first 280 patients who received TXA after protocol initiation. Outcome measurements included postoperative changes in hemoglobin and hematocrit, LOS, pain scores, destination of discharge, and steps ambulated with PT over 5 sessions. RESULTS: TXA administration resulted in less overall drops in hemoglobin (P < .001) and hematocrit levels (P < .001). Moreover, patients administered TXA ambulated more than their counterparts during every PT session, which was statistically significant during the second (P = .010), third (P = .011), and fourth (P = .024) sessions. On average, the TXA cohort ambulated 20% more per PT session than patients who did not receive TXA (P < .001). TXA administration did not influence pain levels during PT, hospital LOS, or discharge destination in this investigation. CONCLUSIONS: It is well known that TXA reduces postoperative anemia, but this study also demonstrates that it confers early perioperative functional benefits for TKA patients. Potential mechanisms for this benefit include reduced rates of postoperative anemia and reduced rates of hemarthroses.

Decreased risk of knee buckling with adductor canal block versus femoral nerve block in total knee arthroplasty: a retrospective cohort study.

BACKGROUND: Femoral nerve (FNB) and adductor canal blocks (ACB) are used in the setting of total knee arthroplasty (TKA), but neither has been demonstrated to be clearly superior. Although dynamometer studies have shown ACBs spare perioperative quadriceps function when compared to FNBs, ACBs have been widely adopted in orthopaedic surgery without significant evidence that they decrease the risk of perioperative falls. METHODS: All patients who received single-shot FNB (129 patients) or ACB (150 patients) at our institution for unilateral primary TKA from April 2014 to September 2015 were retrospectively reviewed for perioperative falls or near-falls during physical therapy and inpatient care. RESULTS: There were significantly more "near-falls" with documented episodes of knee buckling in the FNB group (17 vs 3, P = .0004). These patients' first buckling episode occurred at an average of 21.1 hours postoperatively (standard deviation 5.83, range 13.83-41.15). There were no significant differences in pain scores between the 2 groups at any of the time periods measured; however, patients in the FNB group consumed significantly fewer opioids on postoperative day 1 than the ACB group (59 morphine equivalents vs 73, P = .004). CONCLUSIONS: A significantly higher rate of near-falls with knee buckling during in-hospital physical therapy was discovered in the FNB group. With increasing numbers of TKAs being performed on a "fast-track" discharge model, these results must be seriously considered, particularly in patients planning to go home the same day, to reduce the risk of postoperative falls. These data support the recent clinical data trend favoring ACB over FNB in orthopaedic surgery.

Risk factors for conversion surgery to total hip arthroplasty of a hemiarthroplasty performed for a femoral neck fracture.

INTRODUCTION: The purpose of this study was to determine risk factors for conversion to total hip arthroplasty (THA) in patients originally treated with hemiarthroplasty (HA) for displaced femoral neck fractures. METHODS: In this case-controlled study, we identified 54 patients who were treated with HA for femoral neck fracture (FNF) who subsequently underwent conversion to THA at our institution between 2003 and 2013. We randomly selected 142 control patients who underwent HA for a displaced FNF without conversion surgery during the same time period. We compared demographic data, implant parameters, and radiographic data between the groups to identify risk factors for conversion surgery. RESULTS: In the univariate analysis, younger age at index surgery (mean 75 vs. 80 years, p = 0.006), higher body mass index (26.1 vs. 23.7, p = 0.031), bipolar prosthesis (20% vs. 36%, p = 0.024), absence of dementia (6% vs. 23%, p = 0.01), increased leg length compared to contralateral limb (6.5 mm vs. 0.2 mm, p<0.001), and increased HA femoral head size compared to the contralateral femoral head (2.7 mm vs. 1.5 mm, p = 0.02) were associated with a significantly increased risk of conversion surgery. In the multivariate logistic regression, decreased age at index surgery, no dementia, use of a bipolar head, and increased leg length discrepancy (LLD) were associated with risk of conversion. CONCLUSIONS: Patient characteristics, including younger age, increased BMI, and absence of dementia can lead to increased risk for conversion of HA to THA. Intraoperative considerations of head size and increase in ipsilateral LLD may increase the risk of conversion surgery. These factors should be considered by surgeons who employ HA for displaced FNFs.

Creation of an Online Wiki Improves Post-Operative Surgical Protocol Adherence in Arthroplasty Patients.

BACKGROUND: Perioperative care pathways are tools used in high-volume clinical settings to standardize care, reduce variability, and improve outcomes. However, the mechanism by which the information is transmitted to other caregivers is often inconsistent and error-prone. At our institution, we developed an online, user-editable ("wiki") database to communicate post-operative protocols. The purpose of this study is to evaluate the hypothesis that implementation of the wiki would improve protocol adherence and reduce unintentional deviations inpatient care. METHODS: We conducted a retrospective review of patients who underwent primary lower extremity arthroplasty at our institution during three 6-month time periods including immediately before, 6 months after, and 2 years following introduction of the wiki. Adherence to defined perioperative care pathways (laboratory studies, post-operative imaging, perioperative antibiotics, and inpatient pain medications) was compared between the groups. RESULTS: After wiki implementation, adherence to protocols improved significantly for laboratory orders (P < .0001), imaging (P < .001), pain control regimen (P = .03), and overall protocol adherence (P < .001). Improvements were seen in some areas almost immediately, while others did not show improvements until 2 years after implementation. Costs associated with unnecessary testing were reduced by 82%. CONCLUSION: Development of an online wiki for tracking post-operative protocols improves care pathway adherence and reduces variability in care while lowering costs associated with unnecessary testing, although some benefits may not be immediately realized. Several practical barriers to implementing the wiki are also discussed, along with proposed solutions.

IgH class switching and translocations use a robust non-classical end-joining pathway.

Immunoglobulin variable region exons are assembled in developing B cells by V(D)J recombination. Once mature, these cells undergo class-switch recombination (CSR) when activated by antigen. CSR changes the heavy chain constant region exons (Ch) expressed with a given variable region exon from Cmu to a downstream Ch (for example, Cgamma, Cepsilon or Calpha), thereby switching expression from IgM to IgG, IgE or IgA. Both V(D)J recombination and CSR involve the introduction of DNA double-strand breaks and their repair by means of end joining. For CSR, double-strand breaks are introduced into switch regions that flank Cmu and a downstream Ch, followed by fusion of the broken switch regions. In mammalian cells, the 'classical' non-homologous end joining (C-NHEJ) pathway repairs both general DNA double-strand breaks and programmed double-strand breaks generated by V(D)J recombination. C-NHEJ, as observed during V(D)J recombination, joins ends that lack homology to form 'direct' joins, and also joins ends with several base-pair homologies to form microhomology joins. CSR joins also display direct and microhomology joins, and CSR has been suggested to use C-NHEJ. Xrcc4 and DNA ligase IV (Lig4), which cooperatively catalyse the ligation step of C-NHEJ, are the most specific C-NHEJ factors; they are absolutely required for V(D)J recombination and have no known functions other than C-NHEJ. Here we assess whether C-NHEJ is also critical for CSR by assaying CSR in Xrcc4- or Lig4-deficient mouse B cells. C-NHEJ indeed catalyses CSR joins, because C-NHEJ-deficient B cells had decreased CSR and substantial levels of IgH locus (immunoglobulin heavy chain, encoded by Igh) chromosomal breaks. However, an alternative end-joining pathway, which is markedly biased towards microhomology joins, supports CSR at unexpectedly robust levels in C-NHEJ-deficient B cells. In the absence of C-NHEJ, this alternative end-joining pathway also frequently joins Igh locus breaks to other chromosomes to generate translocations.