Arthrodesis using Iliac Crest autograft in revision surgery of the first metatarsophalangeal joint total arthroplasty for the treatment of Hallux Rigidus: a retrospective study.

PURPOSE: The treatments for hallux rigidus (HR) encompass a wide spectrum, including conservative methods and surgical approaches such as arthroplasty and arthrodesis. This study aims to evaluate the outcomes of revision with arthrodesis following the failure of the first metatarsophalangeal joint total arthroplasty (MTPJ1TA). MATERIALS AND METHODS: Patients who had surgery at two advanced orthopedic centers between January 1, 2020, and January 1, 2024, were reviewed. Those with at least 6 months of postoperative follow-up were assessed for demographics (gender, age, side), reoperation rates, complications, Visual Analogue Scale (VAS) scores, Foot and Ankle Disability Index (FADI) scores, and American Orthopaedic Foot and Ankle Society Hallux Metatarsophalangeal and Interphalangeal Scale (AOFAS-HMI) scores. Radiological evaluations included hallux valgus angle (HVA), intermetatarsal angle (IMA), dorsiflexion angle (DFA), and first ray length (FRL) in anteroposterior and lateral views. RESULTS: Of 27 patients, 4 were male (15%) and 23 female (85%), with an average age of 56.18 ± 7.49 years (range 41-72). Arthrodesis was performed in 26 patients, with one requiring reoperation due to implant failure. Average VAS scores were 7.14 preoperatively and 3.55 postoperatively (p < 0.05). Average FADI scores were 50.51 preoperatively and 71.51 postoperatively (p < 0.05). Average AOFAS-HMI scores were 51.22 preoperatively and 70.59 postoperatively (p < 0.05). Average HVA was 19.7° preoperatively and 6.29° postoperatively (p < 0.05). Average IMA was 10.66° preoperatively and 11.37° postoperatively (p = 0.406). Average DFA was 34.14° preoperatively and 22.33° postoperatively (p < 0.05). Average anteroposterior FRL was 10.17 cm preoperatively and 10.77 cm postoperatively (p < 0.05). Average lateral FRL was 10.12 cm preoperatively and 10.42 cm postoperatively (p < 0.05). None of the patients in the study exhibited postoperative donor site complications or transfer metatarsalgia, while a 100% rate of bone union was observed. CONCLUSION: We think that revision of MTPJ1TA with arthrodesis is a safe treatment option. Additionally, the use of an iliac crest autograft can be a viable option to restore bone stock and create a biological environment conducive to fusion. This study evaluates revision surgery with arthrodesis in the largest patient group with failed MTPJ1TA, highlighting its significance in the field. However, further studies are needed to determine the ideal surgical procedure.

Feasibility of using diamond-like carbon films in total joint replacements: a review.

Diamond-like Carbon (DLC) has been used as a coating material of choice for a variety of technological applications owing to its favorable bio-tribo-thermo-mechanical characteristics. Here, the possibility of bringing DLC into orthopedic joint implants is examined. With ever increasing number of patients suffering from osteoarthritis as well as with the ingress of the osteoarthritic joints' malaise into younger and more active demographics, there is a pressing need to augment the performance and integrity of conventional total joint replacements (TJRs). Contemporary joint replacement devices use metal-on-polymer articulations to restore function to worn, damaged or diseased cartilage. The wear of polymeric components has been addressed using crosslinking and antioxidants; however, in the context of the metallic components, complications pertaining to corrosion and metal ion release inside the body still persist. Through this review article, we explore the use of DLC coatings on metallic bearing surfaces and elucidate why this technology might be a viable solution for ongoing electrochemical challenges in orthopedics. The different characteristics of DLC coatings and their feasibility in TJRs are examined through assessment of tribo-material characterization methods. A holistic characterization of the coating-substrate interface and the wear performance of such systems are discussed. As with all biomaterials used in TJRs, we need mindful consideration of potential in-vivo challenges. We present a few caveats for DLC coatings including delamination, hydrophobicity, and other conflicting as well as outdating findings in the literature. We recommend prudently exploring DLC films as potential coatings on metallic TJR components to solve the problems pertaining to wear, metal ion release, and corrosion. Ultimately, we advise bringing DLC into clinical use only after addressing all challenges and concerns outlined in this article.

Cost-effectiveness of closed-incision negative pressure therapy in primary total joint arthroplasty: a break-even analysis.

OBJECTIVE: Surgical site complications (SSCs) are the leading cause of unplanned emergency department visits and readmissions following total joint arthroplasty (TJA). The use of closed-incision negative pressure therapy (ciNPT) has shown promise in reducing SSC occurrence. However, no study has evaluated the cost-effectiveness of ciNPT in primary TJA. The purpose of this study was to calculate the break-even absolute risk reduction (ARR) of SSCs, the break-even treatment cost of SSCs, and the break-even cost-of-use for ciNPT, based on existing literature to assess the cost-effectiveness of ciNPT in primary TJA. METHOD: Relevant values for ARR, infection treatment cost and intervention cost were obtained via literature review. A break-even analysis was conducted to investigate the cost-effectiveness of ciNPT use in primary TJA, as well as to derive the ARR, infection treatment cost (Ct) and intervention protocol cost (Cp) values at which ciNPT use becomes cost-effective. RESULTS: The values derived from the literature review were as follows: Cp=$160.76 USD; Ct=$5348.78 USD; ARR=0.0375. The break-even ARR was calculated to be 3.0%, the break-even Cp was calculated to be $200.58 USD, and the break-even Ct was calculated to be $4286.93 USD. The ARR of ciNPT use was greater than the calculated break-even ARR. CONCLUSION: This analysis demonstrated that ciNPT use in primary TJA was cost-effective. By examining the difference between the calculated break-even Cp and the Cp reported in the literature, the cost saved per patient treated with ciNPT can be calculated to be $39.82 USD.

Preoperative optimization of modifiable risk factors is associated with decreased superficial surgical site infections after total joint arthroplasty: a prospective case-control study.

BACKGROUND AND PURPOSE: The aim of our study was to investigate change in modifiable risk factors following preoperative optimization and whether risk of superficial surgical site infection (SSI) after total joint arthroplasty (TJA) could be reduced. METHODS: This is a prospective study of implementation of a preoperative optimization pathway for patients waiting for primary TJA. Information regarding the intervention arm was collected from January 2019 to January 2021, first at decision for operation and then at preoperative assessment 1 week prior to operation. The control arm was included between August 2018 and September 2020 after receiving conventional preoperative preparation and information gathered at preoperative assessment. Follow up occurred 6 weeks postoperatively for both groups. The primary outcome was postoperative superficial SSI. RESULTS: The optimization effort resulted in improvement of weight, anemia, HbA1c, vitamin D, and patient engagement. At preoperative assessment the baseline characteristics of the 2 groups were similar except that the intervention group had substantially more comorbidities. Regarding superficial SSI, association was found with BMI ≥ 30 and HbA1c ≥ 42 mmol/mol in the control group but not in the intervention group. When corrected for differences in ASA classification (reflecting comorbidities), age, and sex, being in the intervention group was associated with lower odds of occurrence of superficial SSI compared with the control group (OR 0.64, 95% confidence interval 0.42-0.97). CONCLUSION: We showed that preoperative optimization in a structured cooperation between hospital and primary care was associated with a reduced risk of superficial SSI.

Orthopaedic Nurse Navigators and Total Joint Arthroplasty Preoperative Optimization: Payer Status and Medication Management-Part Six of the Movement Is Life Special ONJ Series.

This article is the sixth in the Movement is Life series and focuses on insurance coverage and medication management in the perioperative period, 2 tangentially related variables that affect patient outcomes. Our aim is to use current practices and literature to develop recommendations for nurse navigators' execution of preoperative optimization protocols related to payer status and medication management. Discussions with nurse navigators and a literature search were used to gather information and develop recommendations specific to optimizing payer status and medication management. Nurse navigators connected patients to resources and provided education regarding financial concerns and medications, and findings from the literature discussed insurance status among TJA patients. Nurse navigators can contribute to payer status and medication management optimization by providing patient education and resource referrals. In addition, we recommend conducting repeated medication reconciliation and developing awareness of financial resources and perioperative medication management guidelines.

Effective shape of ball-and-socket prosthesis in restoring range of thumb motion for total thumb carpometacarpal joint arthroplasty: three-dimensional motion analysis.

PURPOSE: Total joint arthroplasty (TJA) has often been used to treat thumb carpometacarpal (CMC) osteoarthritis (OA). However, guidelines for the CMC prosthesis shape remain unclear. This study aimed to identify the effective shape of a ball-and-socket prosthesis in restoring the range of thumb motion after TJA. METHODS: The participants were 10 healthy young adult men (22-32 years; 26.8 ± 3.57 [mean ± SD]). CT scans were performed in eight static limb positions during abduction and flexion. We defined three design variables (offset R, height H, and neck rotation angle Φ) as the variables that determine the basic shape of the ball-and-socket prosthesis. The ideal values of these design variables were examined based on the results of a 3D motion analysis, which evaluated the change in the posture of the first metacarpal (r, h, and φ corresponding to R, H, and Φ, respectively) relative to the center of rotation (COR) during abduction and flexion. We also simulated the effect of these design variables on the range of thumb motion after TJA using 3D CAD. RESULTS: We found that the values of r and h averaged over all limb positions were 6.92 ± 1.60 mm and 51.02 ± 1.67 mm, respectively, showing that these values remained constant regardless of limb position. In contrast, φ changed significantly. The simulation results indicated that Φ affected the range of thumb motion after TJA, and Φ = 0° relatively reproduced all limb positions compared to other values. CONCLUSION: Our results suggested that the desirable values of R and H were the average of r and h over several limb positions and that Φ = 0° was effective in restoring the range of thumb motion after TJA. Our results will provide surgeons with new guidelines for selecting a prosthesis.

Metatarsophalangeal Arthroplasty in Hallux Rigidus.

First metatarsophalangeal joint (MTPJ) arthroplasty provides hallux rigidus patients with pain relief and preserved motion, offering an alternative to arthrodesis. Recent advancements in implant technology and surgical techniques have broadened treatment options. Although good outcomes have been documented in the literature, concerns persist regarding increased complications, uncertain long-term efficacy, and challenges in managing failed arthroplasties. Addressing bone loss resulting from the procedure further complicates salvage procedures. Larger cohorts and extended studies are necessary to establish efficacy of first MTPJ arthroplasty. Decisions must weigh the trade-offs between pain relief and potential complications, requiring thorough patient-surgeon discussions.

Surgical Management of Failed First Metatarsophalangeal Joint Arthroplasty.

This article describes the etiology, clinical presentation, surgical management, and outcomes for treatment of the failed first metatarsophalangeal (MTP) joint arthroplasty. Failure following implant arthroplasty typically creates large osseous deficits and surgical management can be difficult. Salvage arthrodesis provides reliable joint stability while maintaining hallux length. Outcomes following conversion of a failed MTP joint arthroplasty to MTP joint arthrodesis have demonstrated consistent pain relief and high satisfaction: however, high rates of complication and nonunion have been reported. Bone graft may be necessary to fill large voids in the joint. Other revision options for failed arthroplasty have been described, but outcomes remain inconsistent and varied. Ultimately, conversion to MTP joint arthrodesis is the recommended intervention for treatment of the failed MTP arthroplasty implant, providing sufficient stability and pain relief.

The effect of a split-dose intravenous dexamethasone and a single high-dose on postoperative blood glucose after total joint arthroplasty: a randomized double-blind placebo-controlled trial.

BACKGROUND: In patients undergoing total joint arthroplasty (TJA), the administration of dexamethasone may contribute to perioperative blood glucose (BG) disturbances, potentially resulting in complications, even in patients without diabetes. This study aimed to demonstrate the impact of different administration regimens of dexamethasone in postoperative BG levels. METHODS: In this randomized, controlled, double-blind trial, 136 patients without diabetes scheduled for TJA were randomly assigned to three groups: two perioperative saline injections (Group A, placebo); a single preoperative injection of 20 mg dexamethasone and a postoperative saline injection (Group B), and two perioperative injections of 10 mg dexamethasone (Group C). Primary outcomes were the postoperative fasting blood glucose (FBG) levels. Secondary outcome parameters were the postoperative postprandial blood glucose (PBG) levels. Postoperative complications within 90 days were also recorded. Risk factors for FBG ≥ 140 mg/dl and PBG ≥ 180 mg/dl were investigated. RESULTS: Compared to Group A, there were transient increases in FBG and PBG on postoperative days (PODs) 0 and 1 in Groups B and C. Statistical differences in FBG and PBG among the three groups were nearly absent from POD 1 onward. Both dexamethasone regimens did not increase the risk for postoperative FBG ≥ 140 mg/dl or PBG ≥ 180 mg/dl. Elevated preoperative HbA1c levels may increase the risk of postoperative FBG ≥ 140 mg/dl or PBG ≥ 180 mg/dl, respectively. CONCLUSION: Perioperative intravenous high-dose dexamethasone to patients without diabetes has transient effects on increasing BG levels after TJA. However, no differences were found between the split-dose and single high-dose regimens. The elevated preoperative HbA1c, but not the dexamethasone regimens were the risk factor for FBG ≥ 140 mg/dl and PBG ≥ 180 mg/dl. TRIAL REGISTRATION: Chinese Clinical Trail Registry, ChiCTR2300069473. Registered 17 March 2023, https://www.chictr.org.cn/showproj.html?proj=186760 .

Bilateral Temporomandibular Joint Reconstruction With Custom Alloplastic Implants for Pediatric Ankylosis.

For pediatric patients with refractory temporomandibular joint (TMJ) ankylosis, reconstruction with autologous techniques such as costochondral grafts or distraction osteogenesis has long been considered the gold standard. Many surgeons believed the use of alloplastic joint replacement to be contraindicated in pediatric patients due to concerns for growth restriction and the limited lifespan of the implants. However, recent data has supported TMJ prostheses in skeletally immature patients. This study aims to present a case series of pediatric patients undergoing bilateral TMJ reconstruction with custom-made implants and evaluate their postoperative results. A retrospective chart review was performed of all consecutive pediatric patients undergoing bilateral alloplastic TMJ reconstruction for refractory ankylosis. All patients underwent bilateral TMJ release and total joint replacement with custom-made implants. Preoperative and postoperative cephalometric and volumetric airway data was obtained using cone-beam computed tomography. Three patients, aged 8 to 17, underwent bilateral TMJ replacement with custom-made implants. There were no postoperative complications, and no implants required explantation or replacement. Postoperatively, all patients had increases in maximal interincisal opening, which was stable over months/years of follow-up. The patients also subjectively reported improved speech and mastication; 1 patient had significant improvements in sleep apnea symptoms. Volumetric airway analysis revealed an average airway size increase of 25.6%. Alloplastic TMJ reconstruction is a safe, effective solution for refractory ankylosis in pediatric patients and represents a promising new frontier in craniofacial surgery. Continued long-term evaluation will provide further evidence of the utility of this procedure.

An analysis of the effect of the COVID-19-induced joint replacement deficit in England, Wales, and Northern Ireland suggests recovery will be protracted.

Aims: The COVID-19 pandemic has disrupted the provision of arthroplasty services in England, Wales, and Northern Ireland. This study aimed to quantify the backlog, analyze national trends, and predict time to recovery. Methods: We performed an analysis of the mandatory prospective national registry of all independent and publicly funded hip, knee, shoulder, elbow, and ankle replacements in England, Wales, and Northern Ireland between January 2019 and December 2022 inclusive, totalling 729,642 operations. The deficit was calculated per year compared to a continuation of 2019 volume. Total deficit of cases between 2020 to 2022 was expressed as a percentage of 2019 volume. Sub-analyses were performed based on procedure type, country, and unit sector. Results: Between January 2020 and December 2022, there was a deficit of 158,994 joint replacements. This is equivalent to over two-thirds of a year of normal expected operating activity (71.6%). There were 104,724 (-47.1%) fewer performed in 2020, 41,928 (-18.9%) fewer performed in 2021, and 12,342 (-5.6%) fewer performed in 2022, respectively, than in 2019. Independent-sector procedures increased to make it the predominant arthroplasty provider (53% in 2022). NHS activity was 73.2% of 2019 levels, while independent activity increased to 126.8%. Wales (-136.3%) and Northern Ireland (-121.3%) recorded deficits of more than a year's worth of procedures, substantially more than England (-66.7%). It would take until 2031 to eliminate this deficit with an immediate expansion of capacity over 2019 levels by 10%. Conclusion: The arthroplasty deficit following the COVID-19 pandemic is now equivalent to over two-thirds of a year of normal operating activity, and continues to increase. Patients awaiting different types of arthroplasty, in each country, have been affected disproportionately. A rapid and significant expansion in services is required to address the deficit, and will still take many years to rectify.

Sensitivity, robustness, and reproducibility of U-shaped delamination test for evaluation of candidate ultra-high molecular weight polyethylene materials for joint replacements.

The delamination of ultra-high molecular weight polyethylene (UHMWPE) in artificial joints is a major cause limiting the long-term clinical results of arthroplasty. However, the conventional test method using simple reciprocation to evaluate the delamination resistance of UHMWPE materials has insufficient detection sensitivity. To reproduce delamination, the unconformity contact must be maintained throughout the test so that the maximum stress is generated below the surface. Therefore, a test method that applies a U-shaped motion comprising two long-linear and one short linear sliding motion was developed. The sensitivity, robustness, and reproducibility of the U-shaped delamination test were investigated and compared with the traditional test method. The traditional test method could reproduce delamination only in materials that had degraded considerably, whereas the U-shaped delamination test could reproduce delamination in a wide range of materials, demonstrating its superior sensitivity. Additionally, using a higher load helped accelerate the test without affecting the test results. The optimal length of the short linear sliding motion was confirmed to be 1 mm. Finally, the inter-laboratory reproducibility of the U-shaped delamination test was confirmed using the round-robin test. The U-shaped delamination test demonstrates high sensitivity, robustness, and reproducibility and contributes to the selection and development of UHMWPE materials and artificial joints with a lower risk of delamination.

How Does the New Australian EQ-5D-5L Value Set Impact Utility Scores? Analysis of Data from the Australian Orthopaedic Association National Joint Replacement Registry.

BACKGROUND: With advances in health state valuation methods, new value sets may be developed for some countries. Quantifying the impact of moving between existing and new value sets is critical for guiding decisions around utility score interpretation, reporting and comparison with published scores. OBJECTIVES: The aim of this study is to examine, using large-scale national registry data, how the new Australian EQ-5D-5L value set impacts utility scores for patients undergoing joint replacement. METHODS: Data from the Australian Orthopaedic Association National Joint Replacement Registry were used for this analysis. All primary total hip (THR), knee (TKR), and shoulder replacement (TSR) procedures between 2018 and 2022 with pre-operative and 6-month post-operative EQ-5D-5L data were included. Utility scores were generated using the 2013 and 2023 Australian value sets ('previous' and 'new' value sets, respectively) and analysed descriptively for each joint replacement cohort. Agreement between the two utility score sets was evaluated using concordance correlation coefficients and Bland-Altman plots. RESULTS: EQ-5D-5L data were available for 17,576 THR, 23,010 TKR, and 1667 TSR procedures. The new value set produced a lowest possible EQ-5D-5L utility score of -0.30 (compared with -0.68 previously) and fewer patients had 'worse-than-dead' quality of life (score < 0.00) before surgery. Mean pre-operative scores were 0.21 (THR), 0.19 (TKR), and 0.17 (TSR) units higher with the new value set, and mean post-operative scores were 0.11-0.14 units higher. The new value set resulted in smaller effect sizes for the THR (1.08 versus 1.23) and TKR cohorts (0.86 versus 0.92). There was moderate-to-good overall agreement (coefficients: 0.70-0.80), but concordance varied by time point. CONCLUSION: Although acceptable agreement was evident, the new Australian value set produces less extreme negative utility scores and markedly higher group-level scores. Transition to reporting new EQ-5D-5L utility scores will require accompanying explanation to signal measurement modifications rather than better quality of life.

Total joint arthroplasty for thumb carpometacarpal joint osteoarthritis: a systematic review and meta-analysis of randomized controlled trials.

BACKGROUND AND PURPOSE: Thumb carpometacarpal (CMC) joint osteoarthritis (OA) is increasingly treated with total joint arthroplasty (TJA). We aimed to perform a systematic review and meta-analysis of the benefits and harms of the TJA for thumb CMC OA compared with other treatment strategies. PATIENTS AND METHODS: We performed a systematic search on MEDLINE and CENTRAL databases on August 2, 2023. We included randomized controlled trials investigating the effect of TJA in people with thumb CMC joint OA regardless of the stage or etiology of the disease or comparator. The outcomes were pooled with a random effect meta-analysis. RESULTS: We identified 4 studies randomizing 420 participants to TJA or trapeziectomy. At 3 months, TJA's benefits for pain may exceed the clinically important difference. However, after 1-year follow-up TJA does not improve pain compared with trapeziectomy (mean difference 0.53 points on a 0 to 10 scale; 95% confidence interval [CI] 0.26-0.81). Furthermore, it provides a transient benefit in hand function at 3 months (measured with Disabilities of Arm, Shoulder, and Hand questionnaire, scale 0-100, lower is better) compared with trapeziectomy with or without ligament reconstruction tendon interposition. The benefit in function diminished to a clinically unimportant level at 1-year follow-up (4.4 points better; CI 0.42-8.4). CONCLUSION: Transient benefit in hand function for TJA implies that it could be a preferable option over trapeziectomy for people who consider fast postoperative recovery important. However, current evidence fails to inform us if TJA carries long-term higher risks of revisions compared with trapeziectomy.

Bundled payments lead to quality improvements in hospitals' skilled nursing facility referral networks.

OBJECTIVES: To assess whether hospitals participating in Medicare's Bundled Payments for Care Improvement (BPCI) program for joint replacement changed their referral patterns to favor higher-quality skilled nursing facilities (SNFs). STUDY DESIGN: Retrospective observational study using 2009-2015 inpatient and outpatient claims from a 20% sample of Medicare beneficiaries undergoing joint replacement in US hospitals (N = 146,074) linked with data from Medicare's BPCI program and Nursing Home Compare. METHODS: We ran fixed effect regression models regressing BPCI participation on hospital-SNF referral patterns (number of SNF discharges, number of SNF partners, and SNF referral concentration) and SNF quality (facility inspection survey rating, patient outcome rating, staffing rating, and registered nurse staffing rating). RESULTS: We found that BPCI participation was associated with a decrease in the number of SNF referrals and no significant change in the number of SNF partners or concentration of SNF partners. BPCI participation was associated with discharge to SNFs with a higher patient outcome rating by 0.04 stars (95% CI, 0.04-0.26). BPCI participation was not associated with improvements in discharge to SNFs with a higher facility survey rating (95% CI, -0.03 to 0.11), staffing rating (95% CI, -0.07 to 0.04), or registered nurse staffing rating (95% CI, -0.09 to 0.02). CONCLUSIONS: BPCI participation was associated with lower volume of SNF referrals and small increases in the quality of SNFs to which patients were discharged, without narrowing hospital-SNF referral networks.

Nicotine Screening and Cessation Education Among Patients Awaiting Total Joint Arthroplasty: A Quality Improvement Project.

Orthopedic surgical patients who use nicotine are at a high risk for postoperative complications including infection, respiratory failure, cardiac arrest, and death. Periprosthetic joint infections may result from nicotine-induced immunosuppression and microvascular changes, increasing perioperative morbidity and mortality. These complications result in higher health care costs, increased length of stay, and loss of reimbursement due to readmissions. Four weeks of nicotine cessation prior to arthroplasty decreases these risks; however, perioperative teams may lack reliable nicotine screening and cessation education methods. This project identified inconsistencies in nicotine screening and cessation counseling in the preoperative setting, which contributed to surgery cancellations among patients who required to demonstrate nicotine cessation preoperatively. Standardization of preoperative nicotine screening and patient cessation education resources can improve the identification of orthopedic patients who use nicotine and provide concrete, proven methods of achieving nicotine cessation prior to elective primary arthroplasty. Investment from perioperative staff is essential to ensure success.

Orthopaedic Nurse Navigators and Total Joint Arthroplasty Preoperative Optimization: Mental Health and Housing Status-Part Five of the Movement Is Life Special ONJ Series.

Mental health and housing status have the potential to impact total joint arthroplasty (TJA) outcomes and are common TJA eligibility criteria that prevent patients from receiving surgery. Our aim was to formulate recommendations for how nurse navigators can assist patients with managing mental health and housing concerns. Through discussions with nurse navigators and a literature search across two databases, we gathered information regarding the optimization of mental health and housing status among TJA patients. We observed a lack of standardized protocols for addressing these concerns and literature supporting an increased focus on mental health and housing status, indicating the potential for greater nurse navigator involvement in developing and implementing protocols. We recommend nurse navigators use screening tools to identify mental health and housing concerns and offer the suggested resources to support patients in an effort to improve postoperative outcomes and decrease surgical risks.