Administration of Low-dose Hyperbaric Bupivacaine for Spinal Anesthesia in the Setting of Outpatient Arthroplasty.

INTRODUCTION: With the rise of ambulatory surgery centers (ASCs), rapid motor and sensory recovery after anesthesia is crucial. The purpose of this study was to evaluate the safety and efficacy of low-dose single-shot hyperbaric bupivacaine for spinal anesthesia (SA) for patients undergoing outpatient arthroplasty. METHODS: Data were reviewed from a single ASC from 2018 to 2020 for two arthroplasty-trained surgeons for all patients with primary arthroplasties that had administration of low-dose hyperbaric bupivacaine. Data collected from the ASC records were then further evaluated for total spinal block time, length of blockade, time to discharge criteria, visual analog scale (VAS) scores, and time to discharge. RESULTS: Two hundred twenty-seven patients undergoing 244 primary arthroplasties received SA with low-dose hyperbaric bupivacaine. The volume of 0.75% bupivacaine varied: 115 patients received 0.8 mL (6 mg), 111 patients received 1.0 mL (7.5 mg), and 17 patients received 1.2 mL (9 mg). Total SA time averaged 144 minutes with a mean of 30 minutes from post anesthesia care unit arrival to motor recovery. The mean time from post anesthesia care unit arrival to discharge criteria was 89 minutes. The average VAS at discharge was 1.44; the average VAS on POD1 was 3.0. No episodes of urinary retention and no reports of transient neurologic symptoms were noted in the study population. CONCLUSION: Low-dose, single-shot hyperbaric bupivacaine SA is an effective option in the ASC for arthroplasty, providing a fast return of motor function, facilitating rapid discharge, and is safe with a relatively low-risk profile.

A Cautionary Tale: Malaligned Incentives in Total Hip and Knee Arthroplasty Payment Model Reforms Threaten Promising Innovation and Access to Care.

Over the past several years, there have been notable changes and controversies involving Medicare reimbursement for total hip (THA) and total knee arthroplasty (TKA). We have seen the development and implementation of experimental bundled payment model pilot programs goals of improving quality and decreasing overall costs of care during the last decade. Many orthopaedic surgeons have embraced these programs and have demonstrated the ability to succeed in these new models by implementing strategies, such as preservice optimization, to shift care away from inpatient or postdischarge settings and reduce postoperative complications. However, these achievements have been met with continual reductions in surgeon reimbursement rates, lower bundle payment target pricings, modest increases in hospital reimbursement rates, and inappropriate valuations of THA and TKA Common Procedural Terminology (CPT) codes. These challenges have led to an organized advocacy movement and spurred research involving the methods by which improvements have been made throughout the entire episode of arthroplasty care. Collectively, these efforts have recently led to a novel application of CPT codes recognized by payers to potentially capture presurgical optimization work. In this paper, we present an overview of contemporary payment models, summarize notable events involved in the review of THA and TKA CPT codes, review recent changes to THA and TKA reimbursement, and discuss future challenges faced by arthroplasty surgeons that threaten access to high-quality THA and TKA care.

Total Hip Arthroplasty Learning Curves Based on Approach for New Fellowship-trained Surgeons.

INTRODUCTION: There is concern that the direct anterior (DA) approach is associated with a steeper learning curve than the posterolateral (PL) approach in total hip arthroplasty (THA). The purpose of this study was to investigate if the learning curve is similar for newly trained arthroplasty fellowship-trained surgeons using the DA and PL approaches. METHODS: The first 100 primary THA cases of six DA and PL fellowship-trained arthroplasty surgeons were identified and divided into 50 case cohorts. Demographics, indications for surgery, and 90-day Hip Society standardized complications were collected. Variables were analyzed using independent sample t tests, chi-square tests, or Fisher exact tests. RESULTS: In total, there were 600 patients, and no notable differences were observed in revision surgeries, surgical complications, and total complications between the DA and PL groups. Both groups had lower revision surgery rates, surgical complications, and total complications during their second 50 cases. Higher revision surgeries, and surgical and total complication rates were observed among all surgeons during the first 50 cases. DISCUSSION AND CONCLUSION: No differences were observed in the learning curve when comparing the DA and PL approach. With proper training, early-career surgeons can safely perform THA with similar complication rates regardless of the approach.

Microstructure and electrochemical behavior of contemporary Ti6Al4V implant alloys.

Ti6Al4V is the most common titanium alloy within the biomaterial field. While material standards for different variations of this alloy exist, there are only minimal requirements with respect to its microstructure which is directly related to the alloy's properties. Thus, a better understanding of the Ti6Al4V microstructure of common contemporary implant components and its effect on the electrochemical behavior is needed; including additively manufactured (AM) devices. Therefore, this study aimed at characterizing the microstructures of conventional and AM total joint replacement components, and to identify the effect of microstructure on the electrochemical behavior. Thus, 22 components from conventional (surgically retrieved cast and wrought implants) and AM implants (not previously implanted) were analysed to characterize microstructure by means of electron backscatter diffraction (EBSD) and energy dispersive X-Ray spectroscopy (EDS), and tested to determine its electrochemical behavior (potentiodynamic polarization and EIS). The microstructure of the conventional implants varied broadly but could be categorized into four groups as to their grain size and shape: fine equiaxed, coarse equiaxed, bimodal, and lamellar. The AM components exhibited a fifth category: lath-type. The AM components had a network of ß-phase along the α-phase grain boundaries, prior ß-grains, and manufacturing voids. Finally, the electrochemical study showed that the equiaxed coarse grains and lath-type grains (AM components) had inferior electrochemical behavior, whereas cast alloys had superior electrochemical behaviour; fine-grained wrought alloys likely provide the best compromise between electrochemical and mechanical properties.

Implementation of a Dedicated Orthopaedic Trauma Room in Hip and Femur Fracture Care: A 17-Year Analysis.

OBJECTIVE: To examine the effects of implementing a dedicated orthopaedic trauma room (DOTR) on hip and femur fracture care. DESIGN: A retrospective cohort study. Setting: Level 1 trauma center. Patients: 2928 patients with femoral neck, pertrochanteric, and femoral shaft and distal femur (FSDF) fractures. INTERVENTION: Implementation of a DOTR. MAIN OUTCOME MEASURES: Hospital length of stay (LOS), emergency department (ED) LOS, intensive care unit (ICU) LOS, and time to operating room (TTOR). RESULTS: Implementation of a DOTR resulted in significant improvement in TTOR for all patient groups ( P < 0.05). We found shorter TTOR for pertrochanteric ( P < 0.001), femoral neck ( P = 0.039), and FSDF groups ( P = 0.046). Total hospital LOS was shorter for patients with pertrochanteric ( P < 0.001) and femoral neck fractures ( P = 0.044). Patients with pertrochanteric hip fractures demonstrated shorter ICU LOS ( P < 0.001). No LOS improvements were observed among patients in the FSDF group. ED LOS was significantly longer in all patient groups ( P < 0.001). CONCLUSIONS: Implementation of a DOTR was associated with shorter TTOR, shorter hospital and ICU LOS, and longer ED LOS. There was a greater number of patients transferred into the investigating institution and fewer patients transferred out. These data support the utility of a DOTR as it relates to an improvement in hospital stay-related outcomes in patients with fractures of the hip and femur. Our results suggest that a DOTR in a Level I trauma hospital is associated with improvement in patient care. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Treatment of Medial Collateral Ligament Injury During Total Knee Arthroplasty With Internal Suture Brace Augmentation: A Cadaveric and Biomechanical Study.

Intraoperative medial collateral ligament (MCL) injury during total knee arthroplasty (TKA) is a serious complication. External bracing and/or conversion to a constrained implant has previously been studied. The technique of using an internal high-strength suture brace to augment an MCL repair has been evaluated in the nonarthroplasty patient and could provide an alternate solution. The goal of this study was to determine whether MCL repair with internal suture bracing restores stability of the implanted knee joint. A robotic simulator completed laxity testing on 5 cadaveric knee specimens in 4 sequential phases: (1) intact knee, (2) after implantation with TKA, (3) after sectioning of the MCL, and (4) after MCL repair with suture brace augmentation. Laxity was compared between the different test phases throughout range of motion. Subsequently, the internal brace was tested to failure under valgus load. The MCL repair with internal bracing was effective at restoring laxity in varus-valgus, internal-external, and medial-lateral degrees of freedom through midflexion, with limited support at deeper flexion angles and in anterior-posterior laxity. Rotational laxity was not significantly different than intact knee laxity. Generally, medial-lateral translations were less and anterior-posterior translations were greater and were significantly different at 30° to 45° and 90°, respectively. The mean failure moment was 46.4±9.1 Nm, with the primary mode of failure being MCL repair. Primary MCL repair with internal bracing using a high-strength suture augment showed the potential to provide adequate stability and strength to correct MCL incompetence in TKA without the use of an external knee brace or constrained implants. [Orthopedics. 2022;45(5):e269-e275.].

Comparison of a Smartphone App to Manual Knee Range of Motion Measurements.

Background: Digital technology has emerged as a useful tool for preoperative and postoperative patient engagement and for remote patient monitoring. Smartphones are equipped with motion-sensing technology, and apps can be designed which use these features to create a simple method for measuring range of motion. The purpose of this study was to determine the accuracy of digital technology in assessing knee range of motion using a smartphone app, compared to traditional goniometric measurements in an office setting. Methods: Fifty-three (53) patients in a clinical practice were enrolled between October 2019 and March 2020. Three separate measurements were taken during the patient encounter: (1) the surgeon, (2) the app, and (3) the physical therapist. Intraclass correlations were computed to assess the agreement between (1) the surgeon and app and (2) that between the physical therapist and surgeon. Results: When measuring flexion, the correlation between either the surgeon or therapist with the app was good, whereas the comparison between the surgeon and therapist was moderate. All extension measurement comparisons, between the app, surgeon, and therapist, showed moderate correlation. Limits of agreements showed that 80% of the difference between surgeon and app is within 10 degrees for extension and 11 degrees for flexion. Body mass index did not affect the accuracy of the measurements. Conclusion: Digital app measurements were comparable to measurements made by either a surgeon or physical therapist with a manual goniometer in the clinical setting and may be beneficial for measuring and monitoring patients' range of motion remotely.

John N. Insall Award: MARCQI's Pain-Control Optimization Pathway (POP): Impact of Registry Data and Education on Opioid Utilization.

BACKGROUND: In 2019, the Michigan Arthroplasty Registry Collaborative Quality Initiative (MARCQI) recommended an evidence-based opioid pain pathway to participating physicians and hospitals for patients undergoing total joint arthroplasty (TJA). The purpose of this study was to determine if the education could influence and have lasting effects on the prescribing patterns for TJA patients. METHODS: Using the MARCQI database, the number of oral morphine equivalents (OMEs) prescribed at discharge were collected from January 2018 through December 2019 for all primary arthroplasty procedures. Periods compared included before and after July 2018 Michigan opioid laws as well as before and after the March 2019 MARCQI recommendations. The data compared total hip arthroplasty (THA) and total knee arthroplasty (TKA) patients, opioid-naive vs opioid-tolerant patients, individual surgeons, and MARCQI sites. RESULTS: The data included 84,998 TJAs: 22,774 opioid-naive THAs, 9124 opioid-tolerant THAs, 40,882 opioid-naive TKAs, and 12,218 opioid-tolerant TKAs. In all the groups and at all time periods there were a significant decrease in prescriptions (P < .001). Individual surgeons and participating sites also demonstrated decreased OMEs on discharge after the recommendations. Between the first and last months of collection, this represented an overall decrease of opioid OMEs for THA by 47.1% for opioid-naive patients and 53.4% for opioid-tolerant patients. For TKA patients, the OME decrease was 48.3% for opioid-naive patients, and 48.4% for opioid-tolerant patients. CONCLUSION: The MARCQI pain control optimization pathway (POP) program has been successful in drastically reducing opioid prescribing with lasting effects, which has substantially limited the overall opioid prescription burden for patients undergoing arthroplasty.

Quantifying Patient Engagement in Total Joint Arthroplasty Using Digital Application-Based Technology.

BACKGROUND: Digital patient engagement has been suggested as a mean to increase patient activation and patient satisfaction after total joint arthroplasty. The purpose of this study was to assess patient engagement with application-based educational tools and to explore what content was most useful to patients in the perioperative period surrounding total hip arthroplasty (THA) and total knee arthroplasty (TKA), respectively. METHODS: Patients undergoing THA and TKA between October 2017 and January 2020 were enrolled to use an application-based digital technology. The App provides comprehensive patient education using a series of modules delivered at set intervals preoperatively and postoperatively. Patient engagement was defined as patients viewing at least one time the modules that were sent, or marking them as completed. Patient satisfaction was assessed using an in-application survey. RESULTS: Complete data were available on 207 patients of which 95 (46%) underwent THA and 112 (54%) underwent TKA. The average age was 60 years. 54% with patients invited to the program completed registration. An average compliance rate of 48% (41 modules engaged out of 83) was observed. Of all modules completed, the top three most popular categories included physical therapy/exercise videos, health literacy, and anxiety/stress/pain management. The least viewed category was nutrition planning and education. CONCLUSION: When presented educational material related to THA and TKA, patients had a high rate of compliance. Digital technology platforms provide a scalable, meaningful approach to engaging patients throughout the continuum of joint replacement care and may serve as a cost-effective adjunct to traditional methods.

Incidence of Pseudotumors in a Dual Modular Stem Construct With and Without Metal-on-Metal Bearing Surface.

BACKGROUND: The purpose of this study was to compare the incidence of pseudotumors in metal-on-metal (MoM) titanium modular neck hip arthroplasties to non-MoM modular neck hip arthroplasties. A secondary goal was to determine whether a correlation exists between elevated metal concentrations and pseudotumor incidence. METHODS: The data were collected and evaluated from 49 MoM joints and 26 non-MoM joints between the years 2012 and 2017. Hip ultrasonography was done after a minimum of 5 years postimplantation. Whole serum metal (titanium, cobalt, and chromium) concentrations were measured at the hip ultrasonography study. RESULTS: The average time elapsed between surgery and ultrasonography visit was 7.6 years. In the 49 patients with MoM joints, 22.4% (n = 11) had a pseudotumor. In the 26 patients with non-MoM joints, 9.1% of metal-on-polyethylene hips (n = 1) and 0% of ceramic-on-ceramic/polyethylene hips developed a pseudotumor. No significant statistical correlation was observed between serum metal concentrations and pseudotumor formation (P > 0.05). A significant correlation was observed of serum titanium concentration to pseudotumor size (P = 0.024). CONCLUSION: The incidence of pseudotumor formation in MoM total hip arthroplasties was more than five times the incidence associated with non-MoM bearings. The correlation between serum titanium concentration and pseudotumor size suggests that titanium levels may be a useful indicator for pseudotumor formation in patients with this particular titanium modular neck femoral implant. No notable correlation was observed between serum cobalt and chromium concentration and pseudotumor formation or size.

Conversion Total Knee Arthroplasty: Prior Fracture or Osteotomy Around the Knee Leads to Increased Resource Utilization.

BACKGROUND: Prior knee surgery before total knee arthroplasty (TKA) puts patients at higher risk of inferior outcomes and increased care cost. This study compares intraoperative and postoperative variables including procedure duration, components, length of stay, readmission, complications, and reoperations among patients undergoing conversion TKA. METHODS: Primary TKA from a single-surgeon database identified 130 patients with prior knee surgery to form a "conversion" cohort. One-to-one matching identified 130 patients of similar age, American Society of Anesthesiologists score, body mass index, and gender without prior knee surgery for comparison. Perioperative and 90-day postoperative variables were compared between patients with and without prior surgery, within the conversion group based on the type of prior surgery, and whether the prior surgery was bony or soft tissue. RESULTS: The conversion group had longer mean operative time (96.1 vs 90.0 minutes, P = .01), higher revision component utilization (8.5% vs 0.8%, P = .005), and higher calculated blood loss (1440 vs 1249 mL, P = .004). Thirty-eight patients with prior fracture or osteotomy were compared to the remaining 92 patients in the conversion group and showed longer operative time (107.1 vs 91.3 minutes, P < .001), higher 90-day readmissions (18.4% vs 3.3%, P = .003), more complications (23.7% vs 8.7%, P = .021), and greater utilization of revision components (26.3% vs 1.1%, P < .001). CONCLUSION: Patients undergoing conversion TKA required increased resource utilization, particularly patients with a prior osteotomy or fracture. Policymakers should consider these variables, as they did in conversion THA, in adding a code to account for increased case complexity and resource utilization.

COVID-19 Impact on Young Arthroplasty Surgeons.

BACKGROUND: The current coronavirus crisis, COVID-19, has affected all orthopedic surgeons. Surgeons at early stages of their career are at risk of being affected differently than their more established counterparts. METHODS: We conducted an online survey for members of the Young Arthroplasty Group to determine what effects this had on their current practice. RESULTS: Nearly 40% of our surveyed group responded ranging from residents, fellows, and early career surgeons. All groups had been affected by the crisis, with different impacts on each subgroup. CONCLUSION: COVID-19 had significant impact on young surgeons affecting their compensation, redeployment, and career advancement. Available resources should be offered to this group, where available, to mitigate the impact of the crisis.

Veterans Undergoing Total Hip and Knee Arthroplasty: 30-day Outcomes as Compared to the General Population.

INTRODUCTION: The Veterans Affairs (VA) health system is vital to providing joint replacement care to our retired service members but has come under recent scrutiny. The purpose of this study was to compare the short-term outcomes after total hip arthroplasty (THA) and total knee arthroplasty (TKA) between the VA cohort and the general cohort. METHODS: We retrospectively reviewed 10.460 patients with primary THA and TKA from the Veterans Affairs Corporate Data Warehouse. As a control group, we queried the American College of Surgeons-National Surgical Quality Improvement Program database and identified 58,820 patients with primary THA and TKA over the same time period. We compared length of stay, mortality rates, 30-day complication rates, and 30-day readmissions. We performed a multivariate logistic regression analysis to identify the independent effect of the VA system on adverse outcomes. RESULTS: Veterans are more likely to be men (93% versus 41%, P < 0.001) and have increased rates of medical comorbidities (all P < 0.001). The rate of short-term complications (all P < 0.001) were all higher in the VA cohort. When controlling for demographics and medical comorbidities, VA patients were more likely to have a readmission (P < 0.001), prolonged length of stay > 4 days (P < 0.001), and experience a complication within 30 days (P < 0.001). DISCUSSION: Despite controlling for higher rates of medical comorbidities, VA patients undergoing primary THA and TKA had poorer short-term outcomes than the civilian cohort. Additional research is needed to ensure our veteran cohort is appropriately optimized and address the discrepancy with the outcomes of the civilian.

Comparison of Harris Hip Scores and Revision Rates in Metal-on-Metal Versus Non-Metal-on-Metal Total Hip Arthroplasty.

INTRODUCTION: This study compares functional outcome scores and revision rates between metal-on-metal (MoM) and non-MoM total hip arthroplasty patients. METHODS: A cohort of 75 patients who underwent implantation of the same dual modular hip arthroplasty between the years of 2004 and 2010 was enrolled. Patients were subsequently evaluated in 2015 to 2017 for joint revision history and functionality, as measured by the Harris hip score (HHS). Patients requiring a revision arthroplasty were not included in the HHS analysis. RESULTS: A total of 49 patients had MoM implants (65.3%), and 26 patients had non-MoM implants (34.8%). At a mean follow-up of 7.6 years, 10.2% (5/49) of MoM prostheses required revision, whereas 3.8% (1/26) of non-MoM prostheses required revision (P = 0.334). The mean HHS in the MoM cohort was 89.8, compared with 88.1 in the non-MoM cohort (P = 0.69). CONCLUSION: HHSs were not notably different between cohorts. The MoM cohort had three times as many revisions as the non-MoM cohort, but given the numbers available, this difference did not reach significance. Given the clinical importance of these revision data, further study is warranted to determine survivorship of the MoM versus non-MoM total hip arthroplasty at long-term follow-up.

Radiographic Predictors of Screw Cutout for Intertrochanteric Fractures Treated With Cephalomedullary Nails.

The objective of this study was to determine the predictive value of tip-apex distance (TAD) and Parker's ratio for screw cutout after treatment of intertrochanteric hip fractures with a long cephalomedullary nail. A total of 97 patients with AO/OTA 31-A1-A3 intertrochanteric fractures and a minimum follow-up of 8 weeks were included. Increased Parker's ratio on the anteroposterior radiograph (OR = 1.386, p < .003) and lateral radiograph (OR = 1.138, p < .028) was significantly associated with screw cutout. In a multivariable regression analysis, only the Parker's anteroposterior ratio was significantly associated with risk of screw cutout (OR = 1.393, p = .004), but TAD (OR = 0.977, p = .764) and Parker's lateral ratio (OR 1.032, p = .710) were not independent predictors of cutout. The study concluded that Parker's anteroposterior ratio is the most helpful measurement in predicting screw cutout. (Journal of Surgical Orthopaedic Advances 28(2):115-120, 2019).

Nationwide Organism Susceptibility Patterns to Common Preoperative Prophylactic Antibiotics: What Are We Covering?

BACKGROUND: Many periprosthetic joint infections (PJIs) are caused by organisms not susceptible to first-generation cephalosporins. We sought to evaluate the national susceptibility patterns of organisms to cefazolin and, or oxacillin, clindamycin, and vancomycin using antibiogram data. METHODS: Publically available regional and state antibiograms were evaluated for antibiotic susceptibility patterns to commonly infecting gram-positive organisms. The number of isolates tested in each antibiogram and percent of strains susceptible to oxacillin, clindamycin, and vancomycin were recorded. Oxacillin is used as a surrogate to cefazolin in antibiograms. A comparison of antibiotic susceptibilities was performed. RESULTS: Seven state and 38 regional antibiograms were reviewed. Oxacillin was a sensitive antibiotic in 99.2 ± 4.8% of methicillin-sensitive Staphylococcus aureus (MSSA) isolates, 0 ± 0% of methicillin-resistant Staphylococcus aureus (MRSA) isolates, 44.5 ± 13.7% of coagulase-negative staphylococcus organism isolates (CNS), and 30.6 ± 10.5% of Staphylococcus epidermidis isolates. Clindamycin was a sensitive antibiotic in 75.8 ± 8.4% of MSSA isolates, 60.2 ± 13.2% of MRSA isolates, 60.3 ± 11.4% of CNS isolates, and 56.2 ± 6.5% of S epidermidis isolates. Vancomycin was a sensitive antibiotic in 99.9 ± 0.4% of MSSA isolates, 99.8 ± 0.4% of MRSA isolates, 99.8 ± 0.5% of CNS isolates, and 99.6 ± 0.7% of S epidermidis isolates. Clindamycin was significantly less sensitive in MSSA isolates as compared with oxacillin and vancomycin (P < .0001). Oxacillin was significantly less sensitive in CNS, S epidermidis, and MRSA isolates as compared with clindamycin and vancomycin (P < .0001). CONCLUSION: The national clindamycin susceptibility pattern is limited to MSSA and may not have an optimal susceptibility profile suitable for use as a prophylactic antibiotic. Cefazolin continues to have excellent coverage against MSSA.

Inpatient Versus Outpatient Arthroplasty: A Single-Surgeon, Matched Cohort Analysis of 90-Day Complications.

BACKGROUND: Although some prior work supports the safety of same-day arthroplasty performed in a hospital, concerns remain when these procedures are performed in a free-standing ambulatory surgery center. The purpose of this study is to compare 90-day complication rates between matched cohorts that underwent inpatient vs outpatient arthroplasty at an ambulatory surgery center. METHODS: A single-surgeon cohort of 243 consecutive patients who underwent outpatient arthroplasty was matched with 243 inpatients who had the same procedure. One-to-one nearest-neighbor matching with respect to gender, age, American Society of Anesthesiologists Score, and body mass index was utilized. The 486 primary arthroplasties included 178 unicondylar knees (36.6%), 146 total hips (30.0%), 92 total knees (18.9%), and 70 hip resurfacings (14.5%). Ninety-day outcomes including reoperation, readmission, unplanned clinic or emergency department visits, and major and minor complications were compared using a 2-sample proportions test. RESULTS: The 2 cohorts were similar in distribution of demographic variables, demonstrating successful matching. The inpatient and outpatient cohorts both had readmission rates of 2.1% (P = 1.0). With the number of subjects studied, there were no statistically significant differences in rates of major complications (2.1% vs 2.5%, P = 1.0), minor complications (7.0% vs 7.8%, P = .86), reoperations (0.4% vs 2.1%, P = .22), emergency department visits (1.6% vs 2.5%, P = .52), or unplanned clinic visits (3.3% vs 5.8%, P = .19). CONCLUSION: This study suggests that arthroplasty procedures can be performed safely in an ambulatory surgery center among appropriately selected patients without an increased risk of complications.