Anterior variable angle locking neutralisation plate superiority over traditional tension band wiring for treating transverse patella fractures.

Purpose: This paper investigates the biomechanical benefits of using hybrid constructs that combine cannulated screws with tension band wiring (TBW) cerclage compared to cannulated screws with anterior Variable Angle locking neutralisation plates (VA LNP). These enhancements can bear heavier loads and maintain the repaired patella's integrity, in contrast to traditional methods. Method: Eighteen fresh-frozen human cadaver patellae were carefully fractured transversely at their midpoints using a saw. They were then divided into two groups of nine for subsequent utilisation. Fixation methods included Cannulated Screw Fixation added with either TBW or VA LNP Fixation Technique. Cyclic loading simulations (500 cycles) were conducted to mimic knee motion, tracking fracture displacement with Optotrak. After that, the constructs were secured over a servo-hydraulic testing machine to determine the load-to-failure on axial mode. Results: The average fracture displacement for the anterior neutralisation plate group was 0.09 ± 0.12 mm, compared to 0.77 ± 0.54 mm for the tension band wiring with cannulated screw group after 500 cyclic loading. This result is statistically significant (p = 0.004). The anterior neutralisation plate group exhibited a mean load-to-failure of 1359 ± 21.53 N, whereas the tension band wiring group showed 780.1 ± 22.62 N, resulting in a significant difference between the groups (p = 0.007). Conclusion: This research highlights the superior biomechanical advantage of VA LNP over TBW for treating simple transverse patella fractures with two cannulated screws. It also highlights how the TBW is still a valuable option considering the load-to-failure limit. Level of Evidence: Not Applicable.

Comparative study of locking neutralization plate construct versus tension band wiring with a cannulated screw for patella fractures: experimental and finite element analysis.

Transverse patella fractures, accounting for approximately 1% of Orthopedic injuries, pose intricate challenges due to their vital role in knee mechanics. This study aimed to compare the biomechanical performance of a construct, integrating cannulated screws and an anterior locking neutralization plate, with the conventional tension band wiring technique for treating these fractures. Experimental testing and Finite Element Analysis were employed to evaluate the constructs and gain profound insights into their mechanical behavior. Sixteen cadaveric knees were prepared, and transverse patella fractures were induced at the midpoints using a saw. The plate construct and tension band wire fixation were randomly assigned to the specimens. A cyclic test evaluated the implants' durability and stability, simulating knee movement during extension and flexion. Tensile testing assessed the implants' maximum failure force after cyclic testing, while Finite Element Analysis provided detailed insights into stress distribution and deformation patterns. Statistical analysis was exclusively performed for the experimental data. Results showed the plate enhanced stability with significantly lower deformation (0.09 ± 0.12 mm) compared to wire fixation (0.77 ± 0.54 mm) after 500 cycles (p = 0.004). In tensile testing, the construct also demonstrated higher failure resistance (1359 ± 21.53 N) than wire fixation (780.1 ± 22.62N) (p = 0.007). Finite Element Analysis highlighted distinct stress patterns, validating the construct's superiority. This research presents a promising treatment approach for transverse patella fractures with potential clinical impact and future research prospects. This study presents a promising advancement in addressing the intricate challenges of transverse patella fractures, with implications for refining clinical practice. The construct's improved stability and resistance to failure offer potential benefits in postoperative management and patient outcomes.

Cluster-Randomized Trial of Opiate-Sparing Analgesia after Discharge from Elective Hip Surgery.

BACKGROUND: Surgeons have traditionally relied on opiates after hip replacement, despite a growing epidemic of abuse. This study assessed the efficacy of multimodal analgesia and impact of conservative opiate prescribing after discharge from hip surgery. STUDY DESIGN: In this cluster-randomized trial, 235 patients undergoing hip replacement (5 surgeons) received 1 of 3 discharge pain regimens: scheduled-dose multimodal analgesia with a minimal opiate supply (group A), scheduled-dose multimodal analgesia with a traditional opiate supply (group B), or a traditional pro re nata (as needed) opiate regimen alone (group C). Each of the surgeons comprised a distinct cluster and alternated in a randomized sequence between interventions. The multimodal regimen comprised fixed-schedule doses of acetaminophen, meloxicam, and gabapentin. Primary outcomes were daily visual analogue scale pain and opiate use for 30 days. Secondary outcomes included satisfaction, sleep quality, opiate-related symptoms, hip function, and adverse events. The primary intent-to-treat analysis was performed using linear mixed models. RESULTS: Daily pain was significantly lower in group A (coefficient [Coeff] -0.81; p = 0.003) and group B (Coeff -0.61; p = 0.021) relative to group C. Although daily opiate use in group A (Coeff -0.77; p < 0.001) and group B (Coeff -0.30; p = 0.04) was lower than group C, opiate use for group A was also lower than group B (Coeff -0.46; p = 0.002). Duration of opiate use was significantly shorter for group A (1.14 weeks) and group B (1.39 weeks) compared with group C (2.57 weeks). There were fewer opiate-related symptoms, most commonly fatigue, in group A compared with C, but groups B and C were not significantly different. Both multimodal regimens improved satisfaction and sleep, and there were no differences in hip function or adverse events. CONCLUSIONS: Multimodal analgesia with minimal opiates improved pain control while significantly decreasing opiate use and opiate-related adverse effects. It is time to rethink our reliance on opiates after elective operations.

Total Hip Arthroplasty Through the Direct Anterior Approach Using a Bikini Incision Can Be Safely Performed in Obese Patients.

BACKGROUND: Direct anterior approach (DAA) total hip arthroplasty can be performed through a traditional vertical incision or a horizontal (bikini) incision. The purpose of this study is to compare the 2 approaches, performed by a single surgeon past the learning curve, in terms of (1) overall wound complications and (2) patient-reported esthetics at the 6-month follow-up. METHODS: A case-control retrospective study was conducted. Eighty-six bikini DAA patients were matched 3:1 to 230 conventional DAA patients for gender, age, body mass index (BMI), and American Society of Anesthesiologists score. Outcomes evaluated included wound complications, acute periprosthetic joint infection, transfusion, length of surgery, and dysesthesia. A subgroup analysis was also performed on obese patients, BMI greater than 30 kg/m2. Furthermore, the patients rated cosmesis of the incision at 6 months using a Patient Scar Assessment Scale and the Vancouver Scar Assessment Scale. RESULTS: Bikini patients had lower rates of delayed wound healing compared to conventional incision (2.3% vs 6.1%, P = .087). This difference was statistically significant (0% vs 16.6%, P < .05) in obese patients. There was no difference in terms of incision cosmesis between the 2 incision types. CONCLUSION: Our study demonstrates that the DAA total hip arthroplasty can be performed safely through an alternative horizontal bikini incision with complication rates equivalent to conventional incision DAA and to those in other approaches when performed by surgeons in a high volume, efficient hip replacement institution. In patients whose BMI is >30, a potential benefit of the horizontal incision may be lower wound complications. This study design should be performed at other institutions and ideally at a multi-institution level to evaluate if results can be corroborated. Our opinion is that the horizontal bikini incision should be utilized but only after mastery of the DAA approach using the conventional vertical incision.

Mechanical Complications Following Total Hip Arthroplasty Based on Surgical Approach: A Large, Single-Institution Cohort Study.

BACKGROUND: The influence of surgical approach on risk of early postoperative mechanical complications after total hip arthroplasty (THA) continues to be a focus of debate. We performed the first single-institution study on risk of early operative and nonoperative mechanical complications after THA based on approach, with the hypothesis that there would be no clinically significant difference with modern surgical methods. METHODS: A retrospective study was conducted on 16,186 consecutive THA performed from 2010 to 2016. Revision or conversion THA and cases performed for hip fracture, with recalled prostheses, or during a surgeon's learning period were excluded. THAs were performed using direct anterior (DA; n = 5465), direct lateral (DL; n = 8561), or posterolateral approach with soft tissue repair (PL; n = 2160). All mechanical complications within the first 2 years were identified. The primary analysis was a time to event Cox regression, accounting for both patient and surgeon characteristics. RESULTS: Compared with the DL approach, risk of mechanical complications was higher for both DA and PL. Adjusted risk of instability within 2 years was 0.17%, 0.74%, and 1.74% for DL, DA, and PL, respectively. While occurring at similar rates with the PL and DL approaches, the risk of periprosthetic fracture and loosening increased with DA. Consequently, femoral failure, including fracture or loosening, occurred more frequently for DA, with an adjusted incidence of 1.20% vs 0.58% and 0.47%, with DL and PL. CONCLUSION: Even with soft tissue repair, instability continues to occur with increased frequency with the PL approach. While reducing dislocation, a higher risk of femoral failure with DA must also be considered. Nevertheless, the DL approach appears to confer the lowest overall risk of mechanical complications.

2018 John N. Insall Award: Recovery of Knee Flexion With Unsupervised Home Exercise Is Not Inferior to Outpatient Physical Therapy After TKA: A Randomized Trial.

BACKGROUND: Concerns about the cost and convenience of postsurgical physical therapy (PT) have sparked interest in unsupervised, home-based rehabilitation. However, the effectiveness of unsupervised home exercise after primary TKA has not been previously evaluated. QUESTIONS/PURPOSES: (1) Can unsupervised home exercise after surgery provide noninferior recovery of passive knee flexion compared with formal outpatient PT? (2) Does a web-based platform for home-based exercise provide an advantage compared with a printed PT manual? METHODS: We conducted a randomized, noninferiority trial involving 290 patients (20% of the 1464 eligible patients who could be contacted) who underwent primary TKA from March 2016 to April 2018. We included patients > 18 years old who were undergoing primary, unilateral TKA and provided written consent. We excluded patients with preoperative knee flexion < 90°, patients considering surgical intervention in a hip or the contralateral knee, patients discharged to an extended care facility, and revision or conversion TKA. We randomized patients to one of three groups: outpatient PT, unsupervised home exercise using a web-based platform (web PT), or unsupervised home exercise using a printed paper manual (paper PT). We also implemented a "delayed recovery intervention" within the home exercise program, in which patients were obliged to begin outpatient PT if knee flexion was < 70° at 2 weeks or < 90° at 4 weeks. The primary outcome was change in knee flexion from preoperative baseline after 4 to 6 weeks and 6 months. Secondary outcomes included Knee Injury and Osteoarthritis Outcome Score (KOOS), time back to activities of daily living, and time off narcotics. All analyses were intention to treat, and the noninferiority margin was 5% with maximum flexion as the outcome of interest for this parameter. RESULTS: Adjusted differences in change in passive flexion for web PT +3° (95% confidence interval [CI], -1.2° to 6.4°) and paper PT +5° (95% CI, 0.99°-8.6°) were not inferior to outpatient PT based on a predefined 5° margin. Change in knee flexion from baseline was 0° for outpatient PT, -2° for web PT, and -1° for paper PT after 4 to 6 weeks and 8°, 8°, and 12° for the three groups, respectively, after 6 months. Additionally, there was no difference in the change in KOOS from baseline at 4 to 6 weeks or 6 months postoperatively as well as time back to work, driving, and walking without an assistive device. CONCLUSIONS: Unsupervised home exercise is an effective rehabilitation strategy after primary TKA and was noninferior to formal outpatient PT in selected patients. It is worthwhile to reconsider the current practice of automatically designating patients for outpatient PT after primary TKA, because appropriately selected patients with adequate clinical support can achieve similar results at home. LEVEL OF EVIDENCE: Level I, therapeutic study.

Increased Postoperative Glucose Variability Is Associated with Adverse Outcomes Following Total Joint Arthroplasty.

BACKGROUND: Increased glucose variability during hospitalization has been associated with a longer length of stay in the hospital and a higher mortality rate following non-orthopaedic surgical procedures. Our aim was to investigate the association between glucose variability and postoperative complications following total joint arthroplasty. METHODS: We analyzed data on 21,487 patients who had undergone total hip arthroplasty (THA) or total knee arthroplasty (TKA) at a single center from 2001 to 2017. Patients with a minimum of 2 postoperative glucose values per day or >3 values overall were included in the study. Glucose variability was assessed using a coefficient of variation. Adverse outcomes included an increased length of stay in the hospital, 90-day mortality, reoperations, periprosthetic joint infection, and surgical site infection. Periprosthetic joint infection was defined using the Musculoskeletal Infection Society criteria. RESULTS: The final cohort included 2,360 patients who had undergone THA and 2,698 who had undergone TKA; 1,007 (19.9%) had diabetes. Higher glycemic variability was associated with an increased length of stay, 90-day mortality, periprosthetic joint infection, and surgical site infection. Adjusted analysis indicated that for every 10-percentage-point increase in the coefficient of variation, the length of stay increased by 6.1% (95% confidence interval [CI], 5.1% to 7.2%; p < 0.001), the risk of mortality increased by 26% (odds ratio [OR] = 1.26, 95% CI = 0.98 to 1.61; p = 0.07), and the risks of periprosthetic joint infection and surgical site infection increased by 20% (OR = 1.20, 95% CI = 1.02 to 1.41; p = 0.03) and 14% (OR = 1.14, 95% CI = 1.00 to 1.31; p = 0.06), respectively. These associations were independent of the year of surgery, age, body mass index, Elixhauser comorbidity index, diagnosis of diabetes, in-hospital use of insulin or steroids, and mean glucose values during hospitalization. CONCLUSIONS: Higher glucose variability in the postoperative period is associated with increased rates of surgical site and periprosthetic joint infections and may be a useful predictor of the risk of mortality following THA and TKA. Efforts should be made to control the glucose variability in the early postoperative period, and future studies should examine the role of continuous glucose monitoring in a subset of patients with high glucose fluctuations. LEVEL OF EVIDENCE: Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

All Patients Should Be Screened for Diabetes Before Total Joint Arthroplasty.

BACKGROUND: Diabetes is highly prevalent in patients with osteoarthritis before total joint arthroplasty and presents a higher risk of adverse postoperative outcomes. However, the rate of diabetes in this population and optimal screening strategies remain unknown. METHODS: We prospectively screened patients undergoing elective total joint arthroplasty for diabetes using glycated hemoglobin (HbA1c) and fasting blood glucose (FBG) levels. Screening was conducted within 2 time periods between 2012 and 2017. The prevalence of diabetes was assessed using a previous diagnosis of diabetes or, in the absence of diagnosis, by measuring if HbA1c ≥ 6.5% or FBG ≥ 126 mg/dL. Prediabetes was defined as 5.7% ≤ HbA1c ≤ 6.4% or 100 mg/dL ≤ FBG ≤ 125 mg/dL. Occurrence of a 90-day periprosthetic joint infection and wound complications was noted. RESULTS: A total of 1461 patients were included in the study. The prevalence of diabetes was 20.6%; 178 patients (59.1%) had diagnosed diabetes, and 123 patients (40.9%) had undiagnosed diabetes. Prediabetes was identified in 559 patients (38.3%), resulting in a combined total of 860 (58.9%) patients with diabetes and prediabetes. Total diabetic rates were significantly higher in patients aged >65 years, of nonwhite ethnicity, and undergoing total knee arthroplasty. No significant differences in periprosthetic joint infection and wound complications were observed while comparing patients with diagnosed and undiagnosed diabetes. CONCLUSION: A significant proportion of patients with undiagnosed diabetes and prediabetes were identified. Preadmission testing provides an opportunity to identify and address this condition, potentially reducing short-term arthroplasty-related complications and avoiding long-term systemic diabetic complications. We strongly recommend universal glycemic screening to all elective arthroplasty patients.

Diagnosis of Streptococcus canis periprosthetic joint infection: the utility of next-generation sequencing.

A 62-year-old man who had undergone a primary knee arthroplasty 3 years earlier, presented to the emergency department with an infected prosthesis. He underwent prosthesis resection. All cultures failed to identify the infecting organism. Analysis of the intraoperative samples by next-generation sequencing revealed Streptococcus canis (an organism that resides in the oral cavity of dogs). It was later discovered that the patient had sustained a dog scratch injury several days earlier. The patient reports that his dog had licked the scratch. Treatment was delivered based on the sensitivity of S. canis, and the patient has since undergone reimplantation arthroplasty.

Diagnosis of Periprosthetic Joint Infection: The Potential of Next-Generation Sequencing.

BACKGROUND: Next-generation sequencing is a well-established technique for sequencing of DNA and has recently gained attention in many fields of medicine. Our aim was to evaluate the accuracy of next-generation sequencing in identifying the causative organism(s) in patients with periprosthetic joint infection. METHODS: In this prospective study, samples were collected from 65 revision arthroplasties (39 knees and 26 hips) and 17 primary arthroplasties (9 hips and 8 knees). Synovial fluid, deep tissue, and swabs were obtained at the time of the surgical procedure and were shipped to the laboratory for next-generation sequencing. Deep-tissue specimens were also sent to the institutional laboratory for culture. Sensitivity and specificity were calculated for next-generation sequencing, using the Musculoskeletal Infection Society (MSIS) definition of periprosthetic joint infection as the standard. RESULTS: In 28 revisions, the cases were considered to be infected; cultures were positive in 17 cases (60.7% [95% confidence interval (CI), 40.6% to 78.5%]), and next-generation sequencing was positive in 25 cases (89.3% [95% CI, 71.8% to 97.7%]), with concordance between next-generation sequencing and culture in 15 cases. Among the 11 cases of culture-negative periprosthetic joint infection, next-generation sequencing was able to identify an organism in 9 cases (81.8% [95% CI, 48.2% to 97.7%]). Next-generation sequencing identified microbes in 9 (25.0% [95% CI, 12.1% to 42.2%]) of 36 aseptic revisions with negative cultures and in 6 (35.3% [95% CI, 14.2% to 61.7%]) of 17 primary total joint arthroplasties. Next-generation sequencing detected several organisms in most positive samples. However, in the majority of patients who were infected, 1 or 2 organisms were dominant. CONCLUSIONS: Next-generation sequencing may be a useful adjunct in identification of the causative organism(s) in culture-negative periprosthetic joint infection. Our findings suggest that some cases of monomicrobial periprosthetic joint infection may have additional organisms that escape detection when culture is used. Further study is required to determine the clinical implications of isolated organisms in samples from patients who are not thought to be infected. LEVEL OF EVIDENCE: Diagnostic Level I. See Instructions for Authors for a complete description of levels of evidence.

Weighing in on Body Mass Index and Infection After Total Joint Arthroplasty: Is There Evidence for a Body Mass Index Threshold?

BACKGROUND: Although morbid obesity is considered a modifiable risk factor for periprosthetic joint infection (PJI), there is no consensus regarding an appropriate threshold for body mass index (BMI) above which a high risk for infection may outweigh the benefits of surgery. QUESTIONS/PURPOSES: (1) Is there a BMI cutoff threshold that is associated with increased risk for PJI? (2) Is the risk of PJI increased in higher obesity classes? METHODS: A retrospective study was conducted of all primary THAs and TKAs performed at one institution between 2006 and 2015. Overall 19,226 patients were eligible to be included in the study; 1053 patients were excluded as a result of incomplete data, resulting in a final cohort of 18,173 patients (8757 TKAs and 9416 THAs). PJI was defined using the International Consensus Meeting criteria. To ensure accurate followup, and because there is evidence to support the association between obesity and early infection, we identified PJI within 90 days of the index surgery. This relationship was examined separately for BMI as a continuous variable and for each BMI category as defined by the Centers for Disease Control and Prevention (underweight ≤ 18.49 kg/m; normal 18.5-24.9 kg/m; overweight 25-29.9 kg/m; obese class I 30-34.9 kg/m; obese class II 35-39.9 kg/m; obese class III ≥ 40 kg/m). Analyses were performed with logistic regression, accounting for both patient and surgical risk factors. A BMI threshold was evaluated with a receiver operating characteristic (ROC) curve and the Youden index. RESULTS: The area under the ROC curve for BMI and risk of PJI within 90 days was only 0.58 (confidence interval [CI], 0.52-0.63) suggesting such a cutoff was not much better than random chance. Among the BMI classes, patients with class III obesity (≥ 40 kg/m) were the only ones showing a higher risk for PJI within 90 days (odds ratio [OR], 3.09 [1.46-6.54]; p = 0.003). The risk of developing PJI was not greater for overweight (OR, 0.72; 95% CI, 0.38-1.4), class I obese (OR, 1.06; 95% CI, 0.57-2.0), or class II obese (OR, 1.08; 95% CI, 0.52-2.2) patients. Underweight patients also demonstrated no increased risk for PJI (OR, 1.80; 95% CI, 0.23-13.9). CONCLUSIONS: The risk for infection increases gradually throughout the full range of BMI, but no threshold exists. Weight reduction before surgery may mitigate risk for infection for all patients with a BMI above normal. Of note, patients with a BMI > 40 kg/m carried a threefold higher risk for PJI and for these patients, the risks of surgery must be carefully weighed against its benefits. LEVEL OF EVIDENCE: Level III, therapeutic study.

Serum Fructosamine: A Simple and Inexpensive Test for Assessing Preoperative Glycemic Control.

BACKGROUND: Although the medical community acknowledges the importance of preoperative glycemic control, the literature is inconclusive and the proper metric for assessment of glycemic control remains unclear. Serum fructosamine reflects the mean glycemic control in a shorter time period compared with glycated hemoglobin (HbA1c). Our aim was to examine its role in predicting adverse outcomes following total joint arthroplasty. METHODS: Between 2012 and 2013, we screened all patients undergoing total joint arthroplasty preoperatively using serum HbA1c, fructosamine, and blood glucose levels. On the basis of the recommendations of the American Diabetes Association, 7% was chosen as the cutoff for HbA1c being indicative of poor glycemic control. This threshold correlated with a fructosamine level of 292 µmol/L. All patients were followed and total joint arthroplasty complications were evaluated. We were particularly interested in retrieving details on surgical-site infection (superficial and deep). Patients with fructosamine levels of ≥292 µmol/L were compared with those with fructosamine levels of <292 µmol/L. Complications were evaluated in a univariate analysis followed by a stepwise logistic regression analysis. RESULTS: A total of 829 patients undergoing primary total joint arthroplasty were included in the present study. There were 119 patients (14.4%) with a history of diabetes and 308 patients (37.2%) with HbA1c levels in the prediabetic range. Overall, 51 patients had fructosamine levels of ≥292 µmol/L. Twenty patients (39.2%) had a fructosamine level of ≥292 µmol/L but did not have an HbA1c level of ≥7%. Patients with fructosamine levels of ≥292 µmol/L had a significantly higher risk for deep infection (adjusted odds ratio [OR], 6.2 [95% confidence interval (CI), 1.6 to 24.0]; p = 0.009), readmission (adjusted OR, 3.0 [95% CI, 1.1 to 8.1]; p = 0.03), and reoperation (adjusted OR, 3.4 [95% CI, 1.2 to 9.2]; p = 0.02). In the current study with the given sample size, HbA1c levels of ≥7% failed to show any significant correlation with deep infection (p = 0.14), readmission (p = 1.0), or reoperation (p = 0.7). CONCLUSIONS: Serum fructosamine is a simple and inexpensive test that appears to be a good predictor of adverse outcome in patients with known diabetes and those with unrecognized diabetes or hyperglycemia. Our findings suggest that fructosamine can serve as an alternative to HbA1c in the setting of preoperative glycemic assessment. LEVEL OF EVIDENCE: Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Serum D-Dimer Test Is Promising for the Diagnosis of Periprosthetic Joint Infection and Timing of Reimplantation.

BACKGROUND: Despite the availability of a battery of tests, the diagnosis of periprosthetic joint infection (PJI) continues to be challenging. Serum D-dimer assessment is a widely available test that detects fibrinolytic activities that occur during infection. We hypothesized that patients with PJI may have a high level of circulating D-dimer and that the presence of a high level of serum D-dimer may be a sign of persistent infection in patients awaiting reimplantation. METHODS: This prospective study was initiated to enroll patients undergoing primary and revision arthroplasty. Our cohort consisted of 245 patients undergoing primary arthroplasty (n = 23), revision for aseptic failure (n = 86), revision for PJI (n = 57), or reimplantation (n = 29) or who had infection in a site other than a joint (n = 50). PJI was defined using the Musculoskeletal Infection Society criteria. In all patients, serum D-dimer level, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) level were measured preoperatively. RESULTS: The median D-dimer level was significantly higher (p < 0.0001) for the patients with PJI (1,110 ng/mL [range, 243 to 8,487 ng/mL]) than for the patients with aseptic failure (299 ng/mL [range, 106 to 2,571 ng/mL). Using the Youden index, 850 ng/mL was determined as the optimal threshold value for serum D-dimer for the diagnosis of PJI. Serum D-dimer outperformed both ESR and serum CRP, with a sensitivity of 89% and a specificity of 93%. ESR and CRP had a sensitivity of 73% and 79% and a specificity of 78% and 80%, respectively. The sensitivity and specificity of ESR and CRP combined was 84% (95% confidence interval [CI], 76% to 90%) and 47% (95% CI, 36% to 58%), respectively. CONCLUSIONS: It appears that serum D-dimer is a promising marker for the diagnosis of PJI. This test may also have a great utility for determining the optimal timing of reimplantation. LEVEL OF EVIDENCE: Diagnostic Level II. See Instructions for Authors for a complete description of levels of evidence.

Determining the Threshold for HbA1c as a Predictor for Adverse Outcomes After Total Joint Arthroplasty: A Multicenter, Retrospective Study.

BACKGROUND: Although HbA1c is commonly used for assessing glycemic control before surgery, there is no consensus regarding its role and the appropriate threshold in predicting adverse outcomes. This study was designed to evaluate the potential link between HbA1c and subsequent periprosthetic joint infection (PJI), with the intention of determining the optimal threshold for HbA1c. METHODS: This is a multicenter retrospective study, which identified 1645 diabetic patients who underwent primary total joint arthroplasty (1004 knees and 641 hips) between 2001 and 2015. All patients had an HbA1c measured within 3 months of surgery. The primary outcome of interest was a PJI at 1 year based on the Musculoskeletal Infection Society criteria. Secondary outcomes included orthopedic (wound and mechanical complications) and nonorthopedic complications (sepsis, thromboembolism, genitourinary, and cardiovascular complications). A regression analysis was performed to determine the independent influence of HbA1c for predicting PJI. RESULTS: Overall 22 cases of PJI occurred at 1 year (1.3%). HbA1c at a threshold of 7.7 was distinct for predicting PJI (area under the curve, 0.65; 95% confidence interval, 0.51-0.78). Using this threshold, PJI rates increased from 0.8% (11 of 1441) to 5.4% (11 of 204). In the stepwise logistic regression analysis, PJI remained the only variable associated with higher HbA1c (odds ratio, 1.5; confidence interval, 1.2-2.0; P = .0001). There was no association between high HbA1c levels and other complications assessed. CONCLUSION: High HbA1c levels are associated with an increased risk for PJI. A threshold of 7.7% seems to be more indicative of infection than the commonly used 7% and should perhaps be the goal in preoperative patient optimization.