Machine Learning Models Based on a National-Scale Cohort Identify Patients at High Risk for Prolonged Lengths of Stay Following Primary Total Hip Arthroplasty.

BACKGROUND: Existing machine learning models that predicted prolonged lengths of stay (LOS) following primary total hip arthroplasty (THA) were limited by the small training volume and exclusion of important patient factors. This study aimed to develop machine learning models using a national-scale data set and examine their performance in predicting prolonged LOS following THA. METHODS: A total of 246,265 THAs were analyzed from a large database. Prolonged LOS was defined as exceeding the 75th percentile of all LOSs in the cohort. Candidate predictors of prolonged LOS were selected by recursive feature elimination and used to construct four machine learning models-artificial neural network, random forest, histogram-based gradient boosting, and k-nearest neighbor. The model performance was assessed by discrimination, calibration, and utility. RESULTS: All models exhibited excellent performance in discrimination (area under the receiver operating characteristic curve [AUC] = 0.72 to 0.74) and calibration (slope: 0.83 to 1.18, intercept: -0.01 to 0.11, Brier score: 0.185 to 0.192) during both training and testing sessions. The artificial neural network was the best performer with an AUC of 0.73, calibration slope of 0.99, calibration intercept of -0.01, and Brier score of 0.185. All models showed great utility by producing higher net benefits than the default treatment strategies in the decision curve analyses. Age, laboratory tests, and surgical variables were the strongest predictors of prolonged LOS. CONCLUSION: The excellent prediction performance of machine learning models demonstrated their capacity to identify patients prone to prolonged LOS. Many factors contributing to prolonged LOS can be optimized to minimize hospital stay for high-risk patients.

Machine learning models accurately predict recurrent infection following revision total knee arthroplasty for periprosthetic joint infection.

PURPOSE: This study aimed to develop and validate machine-learning models for the prediction of recurrent infection in patients following revision total knee arthroplasty for periprosthetic joint infection. METHODS: A total of 618 consecutive patients underwent revision total knee arthroplasty for periprosthetic joint infection. The patient cohort included 165 patients with confirmed recurrent periprosthetic joint infection (PJI). Potential risk factors including patient demographics and surgical characteristics served as input to three machine-learning models which were developed to predict recurrent periprosthetic joint. The machine-learning models were assessed by discrimination, calibration and decision curve analysis. RESULTS: The factors most significantly associated with recurrent PJI in patients following revision total knee arthroplasty for PJI included irrigation and debridement with/without modular component exchange (p < 0.001), > 4 prior open surgeries (p < 0.001), metastatic disease (p < 0.001), drug abuse (p < 0.001), HIV/AIDS (p < 0.01), presence of Enterococcus species (p < 0.01) and obesity (p < 0.01). The machine-learning models all achieved excellent performance across discrimination (AUC range 0.81-0.84). CONCLUSION: This study developed three machine-learning models for the prediction of recurrent infections in patients following revision total knee arthroplasty for periprosthetic joint infection. The strongest predictors were previous irrigation and debridement with or without modular component exchange and prior open surgeries. The study findings show excellent model performance, highlighting the potential of these computational tools in quantifying increased risks of recurrent PJI to optimize patient outcomes. LEVEL OF EVIDENCE: IV.

The Natural History of Radiolucencies Following Uncemented Total Knee Arthroplasty at 9 Years.

BACKGROUND: Aseptic loosening remains a common cause of failure in total knee arthroplasty (TKA). There is an increased interest in using uncemented TKA to reduce this complication. Radiolucencies (RLs) following uncemented TKA can be concerning. We report on the 9-year history of RLs in patients with uncemented TKA. METHODS: Twenty-one patients (26 knees) were treated with a cruciate-retaining fully porous coated femur/tibia and cemented patella. At final follow-up, 17 patients (22 knees) were available for review. Average follow-up was 9.6 years, average age was 59.1, and average body mass index was 34.1. X-rays were taken at 6 weeks, 1 year, and at final follow-up. RLs were measured using the Knee Society scoring system and read by two separate surgeons. RESULTS: At 6 weeks, we identified RL in all patients on both the tibia and femur. The majority were beneath the tibial tray and femoral chamfer. At 1 year, 4 femurs and 4 tibias showed new RLs (<2 mm) in similar zones. Eighteen femurs and 18 tibias showed fewer or no change in RLs. At final follow-up, no new tibia or femur developed a new RL. In total, 9 of the 22 tibias and 17 of the 22 femurs had remaining RLs, all less than 2 mm and none were progressive or new. Knee Society Score averaged 92.5 (6 weeks), 95.1 (1 year), and 97.3 (final). CONCLUSION: RLs are common following uncemented TKA. Many resolve by 1 year. There does not appear to be any association between the presence of RLs and long-term follow-up function in this group of patients.

Will My Tibial Fracture Heal? Predicting Nonunion at the Time of Definitive Fixation Based on Commonly Available Variables.

BACKGROUND: Accurate prediction of tibial nonunions has eluded researchers. Reliably predicting tibial nonunions at the time of fixation could change management strategies and stimulate further research. QUESTIONS/PURPOSES: We asked (1) whether data from medical records, fracture characteristics, and radiographs obtained at the time of fixation would identify features predictive of tibial fracture nonunion; and (2) whether this information could be used to create a model to assess the chance of nonunion at the time of intramedullary (IM) nail fixation of the tibia. METHODS: We retrospectively reviewed all tibial shaft fractures treated at our center from 2007 to 2014. We conducted a literature review and collected data on 35 factors theorized to contribute to delayed bone healing. Patients were followed to fracture healing or surgery for nonunion. Patients with planned prophylactic nonunion surgery were excluded because their nonunions were anticipated and our focus was on unanticipated nonunions. Our cohort consisted of 382 patients treated with IM nails for tibial shaft fractures (nonunion, 56; healed, 326). Bivariate and multivariate regression techniques and stepwise modeling approaches examined the relationship between variables available at definitive fixation. Factors were included in our model if they were identified as having a modest to large effect size (odds ratio > 2) at the p < 0.05 level. RESULTS: A multiple variable logistic regression model was developed, including seven factors (p < 0.05; odds ratio > 2.0). With these factors, we created the Nonunion Risk Determination (NURD) score. The NURD score assigns 5 points for flaps, 4 points for compartment syndrome, 3 points for chronic condition(s), 2 points for open fractures, 1 point for male gender, and 1 point per grade of American Society of Anesthesiologists Physical Status and percent cortical contact. One point each is subtracted for spiral fractures and for low-energy injuries, which were found to be predictive of union. A NURD score of 0 to 5 had a 2% chance of nonunion; 6 to 8, 22%; 9 to 11, 42%; and > 12, 61%. CONCLUSIONS: The proposed nonunion prediction model (NURDS) seems to have potential to allow clinicians to better determine which patients have a higher risk of nonunion. Future work should be directed at prospectively validating and enhancing this model. LEVEL OF EVIDENCE: Level III, diagnostic study.

Four-Year Outcomes of Cementless Versus Cemented Fixation of a Newly Introduced Total Knee Arthroplasty Design.

BACKGROUND: Aseptic loosening continues to be a major cause of failure of total knee arthroplasty (TKA). Although cemented fixation remains the gold standard, there is renewed interest in cementless fixation as a means of decreasing this risk via biologic fixation. The purpose of this study was to evaluate the clinical outcomes of cemented and cementless versions of a newly introduced TKA design at an average of 4 years postoperatively. MATERIALS AND METHODS: This was a retrospective case-control study of 100 primary TKAs comparing cementless vs cemented TKAs using the same cruciate-retaining implant design (ATTUNE Knee System; DePuy Synthes). Fifty patients undergoing cementless TKA with a mean age of 60.8 years (range, 48-71 years) and body mass index (BMI) of 31.6 kg/m2 (range, 23.7-41.9 kg/m2) were matched to 50 patients undergoing primary cemented TKA with a mean age of 62.7 years (range, 51-73 years) and BMI of 30.1 kg/m2 (range, 24.6-43.9 kg/m2). The mean follow-up was 4.2 years (range, 4.0-4.4 years) in the cementless group and 7.6 years (range, 7.5-7.7 years) in the cemented group. Complications, clinical outcomes using the Knee Society Score (KSS), and radiographic analyses were evaluated at final follow-up. Student's t tests were used for statistical analyses. RESULTS: There was no statistical difference in age, BMI, and preoperative KSS between the two groups (P=.12, P=.15, and P=.55, respectively). There were no complications or reoperations in either cohort. There were no statistical differences in range of motion and total KSS at final follow-up between the two groups. Final total KSS had a mean of 91.1 for the cementless group and 93.7 for the cemented group. There was no radiographic evidence of component subsidence or loosening in either cohort. CONCLUSION: When compared with its cemented counterpart, the newly introduced cementless TKA design had similar excellent clinical improvements and radiologic results at an average of 4 years of follow-up. [Orthopedics. 2024;47(3):161-166.].

Immediate weightbearing is safe after revision total hip arthroplasty for Vancouver B2/B3 periprosthetic femur fractures.

INTRODUCTION: Modular fluted, tapered stems provide a reliable treatment for Vancouver B2/B3 fractures. Historically, these patients had weightbearing restrictions postoperatively. Although full immediate postoperative weightbearing may provide benefits in this patient population, stem subsidence is a concern. QUESTIONS/PURPOSES: The objective of this study was to investigate the effect of post-operative weight-bearing status on stem subsidence in patients treated with modular tapered stems for Vancouver B2 and B3 periprosthetic fractures. We sought to answer two questions: (1) Does full immediate postoperative weightbearing after revision total hip arthroplasty for periprosthetic femur fracture lead to increased stem subsidence compared to protected weightbearing? (2) Is there a mortality difference between these two groups of patients with different weightbearing restrictions? METHODS: From 2009 to 2015 all patients who underwent revision for Vancouver B2/B3 fractures were made non-weightbearing (NWB) for six weeks postoperatively. After 2015, immediate weightbearing as tolerated (WBAT) was allowed postoperatively. We compared stem subsidence between immediate postoperative and final radiographs. Additionally, we performed a Kaplan-Meijer analysis with one-year mortality as an endpoint. RESULTS: The final cohort included forty-seven patients with an average follow-up of 254 days. The average stem subsidence was 1.0 mm (95 % CI, 0.5-1.5 mm) in the NWB cohort and 0.3 mm (95 % CI, 0-0.7 mm) in the WBAT cohort (P = 0.10). In our survivorship analysis, we noted no deaths in the WBAT cohort compared to 17 % mortality in the NWB cohort at the one-year timepoint. CONCLUSION: Allowing patients to weight bear immediately after revision does not increase stem subsidence. Further studies are needed to determine whether early weightbearing provides a mortality benefit.

The natural history of radiolucencies following cemented unicompartmental knee arthroplasty at 7 years.

INTRODUCTION: Radiolucent lines (RLLs) following unicompartmental knee arthroplasty (UKA) can be concerning as aseptic loosening remains a cause of failure in UKA. The aim of our study was to report on the history of RLLs surrounding the components in a cemented medial compartment fixed-bearing UKA as well as the long-term functional outcomes in this group of patients. MATERIAL AND METHODS: In this retrospective consecutive case-series, twenty-eight patients (37 knees) were treated with medial, fixed-bearing cemented unicompartmental knee arthroplasty. At average final follow-up of 7.1 years, 36 knees were available for review. Radiographs were taken at six weeks, one year, and final follow up. RLLs were measured using a novel modification to the Knee Society scoring (KSS) system. RESULTS: At six-weeks, we identified RLLs in 26 tibias and two femurs out of 37 total knees. At one-year, four additional tibias and both femurs showed some progression of their radiolucencies but were < 2 mm total. At final follow-up, 31 of the 36 tibias (86.1%) and five of the 36 femurs (13.9%) had any RLLs. On the tibial side, RLLs were most common in medial/lateral and anterior/posterior aspects of the tibial tray with few found centrally. On the femoral side, the posterior femoral cut accounted for the most RLLs of any zone at all time points. KSS averaged 93.8 at final follow-up and none of the patients required revision surgery. CONCLUSION: RLLs are common following cemented, fixed-bearing UKA. Many seem to progress slowly up to one year but not thereafter. There does not appear to be any association between the presence of these radiolucencies and long-term follow-up function in this group of patients.

Bilateral Extensor Mechanism Allograft Reconstruction in Native Knees: A Case Report.

CASE: A 66-year-old man presented with chronic bilateral extensor mechanism dysfunction and profound patella baja after failed revision surgery for bilateral quadriceps tendon ruptures. Staged bilateral reconstruction with complete extensor mechanism allograft resulted in excellent two-year satisfaction and clinical outcomes. CONCLUSION: Complete extensor mechanism reconstruction can be a successful treatment for chronic quadriceps tendon rupture with profound patella baja.

Poor Patient Follow-up After Metal-on-Metal Total Hip Arthroplasty.

Routine follow-up approximately every 2 to 5 years after total hip arthroplasty (THA) is a common practice. However, although patients are informed of the importance of follow-up, our mean follow-up rate for patients after standard non-metal-on-metal (MOM) THA is only 19%. The US Food and Drug Administration has released several statements on the importance of follow-up every 2 years after MOM THA. With the potential risks of MOM THA apparently widely known, we report on our ability to obtain timely follow-up at 2 separate centers. Two separate centers performed 570 MOM THA procedures between 2002 and 2010. An attempt was made to reach every patient by either telephone or letter to obtain ion levels, radiographs, and examinations. Repeat telephone calls and/or letters to those not reached were made annually. Patients were told of the unique importance of follow-up at each contact. Of the patients, 43% had not been seen within the past 5 years, and only 26% had been seen within the past 2 years. Only 61% had their first measurement of ion levels, and only 30% of patients had a second set of measurement of ion levels. A total of 48 revisions occurred in this group, and 36 patients died. Despite the apparent widespread dissemination of information regarding the potential risks of MOM THA and concerted efforts to contact patients for follow-up, we have been able to achieve a follow-up rate of only 26%. This rate is only marginally better than the mean follow-up for non-MOM THA in our practices. The implications of this poor follow-up are unknown. [Orthopedics. 2022;45(4):e196-e200.].

Open Ankle Fractures: What Predicts Infection? A Multicenter Study.

OBJECTIVE: To identify the patient, injury, and treatment factors associated with an acute infection during the treatment of open ankle fractures in a large multicenter retrospective review. To evaluate the effect of infectious complications on the rates of nonunion, malunion, and loss of reduction. DESIGN: Multicenter retrospective review. SETTING: Sixteen trauma centers. PATIENTS: One thousand and 3 consecutive skeletally mature patients (514 men and 489 women) with open ankle fractures. MAIN OUTCOME MEASURES: Fracture-related infection (FRI) in open ankle fractures. RESULTS: The charts of 1003 consecutive patients were reviewed, and 712 patients (357 women and 355 men) had at least 12 weeks of clinical follow-up. Their average age was 50 years (range 16-96), and average BMI was 31; they sustained OTA/AO types 44A (12%), 44B (58%), and 44C (30%) open ankle fractures. The rate FRI rate was 15%. A multivariable regression analysis identified male sex, diabetes, smoking, immunosuppressant use, time to wound closure, and wound location as independent risk factors for infection. There were 77 cases of malunion, nonunion, loss of reduction, and/or implant failure; FRI was associated with higher rates of these complications (P = 0.01). CONCLUSIONS: Several patient, injury, and surgical factors were associated with FRI in the treatment of open ankle fractures. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Topical Vancomycin Powder Decreases the Proportion of Staphylococcus aureus Found in Culture of Surgical Site Infections in Operatively Treated Fractures.

OBJECTIVES: To determine whether patients with operatively treated fractures and surgical site infection after use of topical vancomycin powder have a lower proportion of Staphylococcus aureus infections than patients who did not receive topical vancomycin powder. DESIGN: Retrospective cohort study. SETTING: Level I trauma center. PATIENTS: Treatment group: 10 of 133 patients (145 fractures) with surgical site infections who received intrawound vancomycin powder at the time of wound closure for fracture fixation. Control group: 175 patients who sustained deep surgical site infections during the same period but did not receive vancomycin powder. INTERVENTION: Vancomycin powder or no vancomycin powder. MAIN OUTCOME MEASUREMENT: Proportion of patients' cultures positive for S. aureus. RESULTS: The proportion of cultures positive for S. aureus was significantly lower in patients with surgical site infection who received vancomycin powder than in those who did not receive vancomycin powder (10% [1 of 10 patients in the treatment group] vs. 50% [87 of 175 patients in the control group]; P = 0.02). A trend was observed for a lower proportion of methicillin-resistant S. aureus (0% vs. 23%; P = 0.12). CONCLUSIONS: Vancomycin powder might alter the bacteriology of surgical site infections and decrease the proportion in culture of the most common organism typically present after fracture surgery infection. These findings suggest that the application of vancomycin powder might change the bacteriology of surgical site infections when they occur, regardless of the effect on overall infection rates. Although our bacteriology results are clinically and statistically significant, these findings must be confirmed in larger randomized controlled trials. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Average narcotic usage in a group of TKA patients following a modern TKA protocol.

INTRODUCTION: The optimal dosing of post-operative total knee arthroplasty (TKA) narcotics is unclear. We report on the average narcotic usage in a group of patients treated with an identical multimodal pain protocol following TKA. MATERIALS AND METHODS: 49 patients undergoing TKA participated in the survey. Patients with pre-op narcotic use, recent prior total joint arthroplasty or study refusal were excluded. All patients received a spinal anesthetic. No pre-surgery narcotics were given. All received an identical local infiltrative anesthetic combination along with a multimodal pain protocol. Patients were placed into an identical rapid rehab program. Narcotic usage during hospitalization was recorded in morphine equivalent doses (MED). Patients were given a journal to record their daily narcotic utilization. RESULTS: Pre-operative pain scores of the excluded groups had slightly higher but clinically insignificant differences compared to the study group. In the hospital, POD1 study group daily MED averaged 28 (range 0-110). POD2 had an average of 33.6 and POD 3 daily usages averaged 28.6 (range 0-100). By the end of week two, the average daily use was 19.2 and 24% patients were off all narcotics. By the end of week four, the average daily usage was 7.5 and 63% of patients were off all narcotics. By 8 weeks, there were no patients still taking narcotics. KSS averaged 76.9 (range 51-97) at the 6 week visit, and 94.2 at the 3-month visit (range 72-100). SUMMARY: This study documents the average needs of an average TKA patient treated with modern pain protocols. The majority of these patients were off narcotics by week four.

Current surgical practice for septic arthritis of the knee in the United States.

For septic arthritis of the knee, we attempted to determine: the preferred surgical technique in the United-States (US), the believed "gold-standard" treatment among others. This was performed by an electronic-survey distributed to all academic orthopaedic faculty throughout the US. The preferred method was arthroscopy (69.8%). Arthroscopy is believed to be the gold-standard in 27.0%, arthrotomy in 29.4%, while 43.5% believe no gold-standard exists. In conclusion the majority of surgeons prefer arthroscopy when managing a native, septic knee in an adult patient. However, there is no national consensus on a gold-standard treatment or the role of synovectomy.

Vancomycin Powder Use in Fractures at High Risk of Surgical Site Infection.

OBJECTIVES: To determine if the use of intrawound vancomycin powder reduces surgical-site infection after open reduction and internal fixation of bicondylar tibial plateau, tibial pilon, and calcaneus fractures. DESIGN: Retrospective analysis. SETTING: Level I trauma center. PATIENTS: All fractures operatively treated from January 2011 to February 2015 were reviewed; 583 high-risk fractures were included, of which 35 received topical vancomycin powder. A previously published prospectively collected cohort of 235 similar high-risk fractures treated at our center from 2007 through 2010 served as a second comparison group. INTERVENTION: Topical vancomycin powder at wound closure. MAIN OUTCOME MEASUREMENTS: Deep surgical-site infection. Analyses used both univariate comparison of all patients and 1:2 matching analysis using both nearest neighbor and propensity-based matching. RESULTS: Compared with a control group of fractures treated during the same time period without vancomycin powder, the infection rate with vancomycin powder was significantly lower [0% (0/35) vs. 10.6% (58/548), P = 0.04]. Compared with our previously published historical infection rate of 13% for these injuries, vancomycin powder was also associated with significantly decreased deep surgical-site infection (0% vs. 13%, P = 0.02). These results agreed with the matched analyses, which also showed lower infection in the vancomycin powder group (0% vs. 11%-16%, P ≤ 0.05). CONCLUSIONS: Vancomycin powder may play a role in lowering surgical-site infection rates after fracture fixation. A larger randomized controlled trial is needed to validate our findings. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Posterior Femoral Cam Decompression Through an Arthroscopic Anterior Approach With Pre-Bent Hip Burrs.

Hip arthroscopy has been increasingly used to treat labral tears and cam and pincer lesions found in femoroacetabular impingement. Although the classic impingement with cam deformity at the proximal femoral anterolateral quadrant is most common, there has been evidence of cam impingement extension to the anteromedial and posterior quadrants of the proximal femur. Posterior cam decompression carries a theoretical risk of vascular insult and subsequent osteonecrosis, which have led investigators to approach these posterior lesions through an open surgical correction. Recent improvements have led to the development of pre-bent burs that allow for bonier resection flexibility. Here, we report on an arthroscopic posterior cam decompression using the traditional anterior portals and curved hip burs via a figure-of-four positioning technique.

Modern full-component aseptic revision total knee arthroplasties have similar recoveries compared with primary total knee arthroplasty patients when applying an enhanced recovery anaesthetic and analgesic protocol.

AIMS: Enhanced perioperative protocols have significantly improved patient recovery following primary total knee arthroplasty (TKA). Little has been investigated the effectiveness of these protocols for revision TKA (RTKA). We report on a matched group of aseptic revision and primary TKA patients treated with an identical pain and rehabilitation programmes. METHODS: Overall, 40 aseptic full-component RTKA patients were matched (surgical date, age, sex, and body mass index (BMI)) to a group of primary cemented TKA patients. All RTKAs had new uncemented stemmed femoral and tibial components with metaphyseal sleeves. Both groups were treated with an identical postoperative pain protocol. Patients were followed for at least two years. Knee Society Scores (KSS) at six weeks and at final follow-up were recorded for both groups. RESULTS: There was no difference in mean length of stay between the primary TKA (1.2 days (0.83 to 2.08)) and RTKA patients (1.4 days (0.91 to 2.08). Mean oral morphine milligram (mg) equivalent dosing (MED) during the hospitalization was 42 mg/day for the primary TKA and 38 mg/day for the RTKA groups. There were two readmissions: gastrointestinal disturbance (RTKA) and urinary retention (primary TKA). There no were reoperations, wound problems, thromboembolic events or manipulations in either group. Mean overall KSS for the RTKA group was 87.3 (45 to 99) at six-week follow-up and 89.1 (52 to 100) at final follow-up (mean 3.9 years, (3.9 to 9.0)). Mean overall KSS for the primary group was 89.9 (71 to 100) at six-week follow-up and 93.42 (73 to 100) at final follow-up (mean 3.5 years (2.5 to 9.2)). CONCLUSION: An identical pain and rehabilitation protocol used for primary TKA patients can enable certain full-component aseptic RTKA patients to have a similar early functional outcome. Cite this article: Bone Joint J 2020;102-B(6 Supple A):96-100.

Tourniquet use for extremity fractures has no adverse effect on number of ventilator days for patients who are treated with reamed femoral or tibial shaft nails.

INTRODUCTION: Concern exists regarding the pulmonary effects of using tourniquets for secondary extremity fractures in patients also undergoing intramedullary nail (IMN) fixation of femoral or tibial shaft fractures. Our hypothesis was that tourniquet use would be associated with increased ventilator days. METHODS: At a Level I trauma center, we conducted a retrospective review of 1966 patients with 2018 fractures (1070 femoral shaft and 948 tibial shaft) treated with IMN from December 2006 to September 2014. Medical record review and bivariate and multiple variable regression analyses were conducted, and the main outcome measurement was number of ventilator days. RESULTS: No statistically significant negative association was found between use of a tourniquet and number of ventilator days in the femoral or tibial fracture group. Use of tourniquets in the upper extremities showed a statistically significant decrease in amount of ventilator days in the femoral group (-2.2 days, p = 0.003) but no association in the tibial group (1.1 days, p = 0.36). Use of tourniquets concurrently in both upper and lower extremities of both femoral and tibial groups also had a protective effect (-6.8 days, p < 0.001 and -2.3 days, p = 0.009, respectively). Stratified and sensitivity analyses (to account for effects of mortality and missing data) showed consistently similar results. CONCLUSION: Tourniquet use for secondary extremity fractures, in patients also undergoing IMN fixation for femoral or tibial shaft fractures, was not associated with an increased number of ventilator days. A potential protective effect of tourniquet use was shown in patients with upper extremity fractures and in those with both upper and lower extremity fractures. LEVEL OF EVIDENCE: Therapeutic Level III (Retrospective cohort study).

A Calcar Collar Is Protective Against Early Torsional/Spiral Periprosthetic Femoral Fracture: A Paired Cadaveric Biomechanical Analysis.

BACKGROUND: Periprosthetic fracture is a leading reason for readmission following total hip arthroplasty. Most of these fractures occur during the early postoperative period before bone ingrowth. Before ingrowth occurs, the femoral component can rotate relative to the femoral canal, causing a spiral fracture pattern. We sought to evaluate, in a paired cadaver model, whether the torsional load to fracture was higher in collared stems. The hypothesis was that collared stems have greater load to fracture under axial and torsional loads compared with collarless stems. METHODS: Twenty-two cadaveric femora (11 matched pairs) with a mean age of 77 ± 10.2 years (range, 54 to 90 years) were harvested. Following dissection, the femora were evaluated with use of a dual x-ray absorptiometry scanner and T scores were recorded. We utilized a common stem that is available with the same intraosseous geometry with and without a collar. For each pair, 1 femur was implanted with a collared stem and the contralateral femur was implanted with a collarless stem with use of a standard broaching technique. A compressive 68-kg load was applied to simulate body weight during ambulation. A rotational displacement was then applied until fracture occurred. Peak torque prior to fracture was measured with use of a torque meter load cell and data acquisition software. RESULTS: The median torque to fracture was 65.4 Nm for collared stems and 43.1 Nm for uncollared stems (p = 0.0014, Wilcoxon signed-rank test). The median T score was -1.95 (range, -4.1 to -0.15). The median difference in torque to fracture was 29.18 Nm. As expected in each case, the mode of failure was a spiral fracture around the implant. CONCLUSIONS: Collared stems seemed to offer a protective effect in torsional loading in this biomechanical model comparing matched femora. CLINICAL RELEVANCE: These results may translate into a protective effect against early periprosthetic Vancouver B2 femoral fractures that occur before osseous integration has occurred.

Novel Application of Exhaled Carbon Monoxide Monitors: Smoking Cessation in Orthopaedic Trauma Patients.

OBJECTIVES: To determine whether an in-office exhaled carbon monoxide (CO) monitor can increase interest in smoking cessation among the orthopaedic trauma population. DESIGN: Prospective. SETTING: Level I trauma center. PATIENTS: One hundred twenty-four orthopaedic trauma patients. INTERVENTION: In-office measurement of exhaled CO. MAIN OUTCOME MEASURES: Stage of change, Likert scale score on willingness to quit today, patient's request for referral to a quitline, and increase in readiness to quit. RESULTS: The use of an exhaled CO monitor increased willingness to quit in 71% of participants still smoking and increased willingness to quit on average by 0.8 points on a 10-point Likert scale (P < 0.001). Fifteen percent of patients modified their stage of change toward quitting. Forty percent of patients after exhaled CO monitor requested referral to a quitline, compared with 4% presurvey (P < 0.001). Anecdotally, most participants were very interested in the monitoring device and its reading, expressing concern with the result. The value of exhaled CO was not associated with any measured outcomes. CONCLUSIONS: The use of an exhaled CO monitor increased willingness to quit smoking in 71% of patients, but the effect size was relatively small (0.8 points on a 10-point Likert scale). However, use of the CO monitor resulted in a large increase (40% vs. 4%) in referral to the national Quitline. Use of the Quitline typically increases the chance of smoking cessation by 10 times the baseline rate, suggesting that this finding might be clinically important. LEVEL OF EVIDENCE: Therapeutic Level II. See Instructions for Authors for a complete description of levels of evidence.

Postoperative Deep Vein Thrombosis, Pulmonary Embolism, and Myocardial Infarction: Complications After Therapeutic Anticoagulation in the Patient With Spine Trauma.

STUDY DESIGN: A retrospective review (2001-2014) was conducted using prospectively collected data at a level I trauma center. OBJECTIVE: We sought to determine the incidence and characteristics of complications occurring secondary to therapeutic anticoagulation in adult spine trauma patients. SUMMARY OF BACKGROUND DATA: Numerous studies have assessed prophylactic anticoagulation after spine surgery, but none has investigated the risks of therapeutic doses of anticoagulation for treatment of postoperative thromboembolic events. METHODS: Patients were included if they sustained a postoperative thromboembolic event (deep venous thrombosis, pulmonary embolism, or myocardial infarction). Patients were excluded if anticoagulation was subtherapeutic. Of 1712 patients, 62 who received therapeutic anticoagulation and 174 propensity-matched control patients who did not receive therapeutic anticoagulation were included in the study. RESULTS: Initial anticoagulation was obtained by heparin infusion (51%), low-molecular-weight heparin (LMWH, 46%), and warfarin (3%). Complications requiring unplanned reoperation occurred in 18% of anticoagulated patients and 10% of nonanticoagulated patients (P = 0.17). The reoperation rate after heparin infusion was 31% and after LMWH was 6.5% (P = 0.02). Epidural hematoma occurred in 3% and 1% of anticoagulated and nonanticoagulated patients, respectively. Multivariate logistic regression analysis of the two groups showed a trend toward increased risk of reoperation in the anticoagulation group. Analysis of the heparin infusion subgroup separate from the LMWH subgroup compared with the control group showed an increased risk of reoperation for any complication (odds ratio, 3.57; P = 0.01) and for bleeding complications (odds ratio, 43.1; P = 0.01). CONCLUSION: This is the first study to quantify complications secondary to postoperative therapeutic anticoagulation in spine patients. Postoperative spine trauma patients who underwent therapeutic anticoagulation experienced an unplanned reoperation rate of 18%, including a 3% incidence of spinal epidural hematoma. Therapeutic anticoagulation using heparin infusion seems to drive the overall rate of reoperation (31%) compared with LMWH. LEVEL OF EVIDENCE: 3.