The relationship between preoperative opioid use and adverse events following total shoulder arthroplasty.

Introduction: Few studies have analyzed the effect of preoperative opioid use on postoperative outcomes after total shoulder arthroplasty (TSA). Methods: Patients undergoing TSA were identified in the Pearldiver Humana Claims Dataset and stratified by level of preoperative opioid use. Primary outcomes were 90-day complications, readmissions, and revision surgery. Chi-square test and ANOVA were used to evaluate categorical and continuous variables respectively. A multivariable logistic regression analysis and a sub analysis excluding fracture as a primary diagnosis were completed. Results: 18,791 patients underwent aTSA and rTSA including 9933 opioid naïve patients, 3016 sporadic opioid users and 5842 persistent opioid users. Significant differences were found in complications (6.0% vs 6.1% vs 9.1%, p < .001), readmission (7.6% vs 8.2% vs 12.6%, p < .001), and revision procedures (1.1% vs 1.1% vs 2.3%, p < .001) which remained significant after excluding fractures. After adjusting for comorbidity burden, persistent opioid use was associated with increased likelihood of complications (OR 1.4, 1.2-1.6), readmission (OR 1.6, 1.5-1.8) and revision procedures (OR 1.9, 1.5-2.4). This association remained after excluding fractures. Conclusion: Persistent preoperative opioid use is associated with increased risk of early postoperative complications, readmission, and revision surgery for patients undergoing shoulder arthroplasty.

Horizontal Cleavage Meniscus Tears: Biomechanics, Indications, Techniques, and Outcomes.

¼ Accounting for up to 24% of all meniscus tears, horizontal cleavage tears (HCTs) are a common pathology orthopaedic practitioners should be comfortable managing.¼ Historically, HCTs were treated with partial meniscectomy; however, recent studies have demonstrated that these procedures have an adverse biomechanical effect, while HCT repairs restore the knee's natural biomechanics.¼ Indications for the surgical repair of HCTs remain disputed, but surgery is generally considered for young, active patients and older patients without significant concomitant osteoarthritis.¼ Early clinical findings surrounding HCT repair are promising. They suggest that this treatment adequately restores meniscus mechanics, leads to good knee functional outcomes, and results in a high likelihood of return to preinjury activity levels.

Influence of Staphylococcus epidermidis on Collagen Crimp Patterns of Soft Tissue Allograft.

BACKGROUND: Postoperative infections, commonly from Staphylococcus epidermidis, may result in anterior cruciate ligament graft failure and necessitate revision surgery. In biomechanical studies, S. epidermidis has been shown to establish biofilms on tendons and reduce graft strength. PURPOSE/HYPOTHESIS: The goal of this study was to determine the effect of bacterial bioburden on the collagen structure of tendon. It was hypothesized that an increase in S. epidermidis biofilm would compromise tendon crimp, a pattern necessary for mechanical integrity, of soft tissue allografts. STUDY DESIGN: Controlled laboratory study. METHODS: Cultures of S. epidermidis were used to inoculate tibialis anterior cadaveric tendons. Conditions assessed included 5 × 105 colony-forming units or concentrated spent media from culture (no living bacteria). Incubation times of 30 minutes, 3 hours, 6 hours, and 24 hours were utilized. Second-harmonic generation imaging allowed for visualization of collagen autofluorescence. Crimp lengths were determined using ImageJ and compared based on incubation time. RESULTS: Incubation time positively correlated with increasing S. epidermidis bioburden. Both fine and coarse crimp patterns lengthened with increasing incubation time. Significant coarse crimp changes were observed after only 30-minute incubations (P < .029), whereas significant fine crimp lengthening occurred after 6 hours (P < .0001). No changes in crimp length were identified after incubation in media lacking living bacteria. CONCLUSION: The results of this study demonstrate that exposure to S. epidermidis negatively affects collagen crimp structure. Structural alterations at the collagen fiber level occur within 30 minutes of exposure to media containing S. epidermidis. CLINICAL RELEVANCE: Our study highlights the need for antimicrobial precautions to prevent graft colonization and maximize graft mechanical strength.

Republication of "A Biomechanical Comparison of Limited Open Versus Krackow Repair for Achilles Tendon Rupture".

Background: Soft tissue complications after Achilles tendon repair has led to increased interest in less invasive techniques. Various limited open techniques have gained popularity as an alternative to open operative repair. The purpose of this study was to biomechanically compare an open Krackow and limited open repair for Achilles tendon rupture. We hypothesized that there would be no statistical difference in load to failure, work to failure, and initial linear stiffness. Methods: A simulated Achilles tendon rupture was created 4 cm proximal to its insertion in 18 fresh-frozen cadaveric below-knee lower limbs. Specimens were randomized to open or limited open PARS Achilles Jig System repair. Repairs were loaded to failure at a rate of 25.4 mm/s to reflect loading during normal ankle range of motion. Load to failure, work to failure, and initial linear stiffness were compared between the 2 repair types. Results: The average load to failure (353.8 ± 88.8 N vs 313.3 ± 99.9 N; P = .38) and work to failure (6.4 ± 2.3 J vs 6.3 ± 3.5 J; P = .904) were not statistically different for Krackow and PARS repair, respectively. Mean initial linear stiffness of the Krackow repair (17.8 ± 5.4 N/mm) was significantly greater than PARS repair (11.8 ± 2.5 N/mm) (P = .011). Conclusion: No significant difference in repair strength was seen, but higher initial linear stiffness for Krackow repair suggests superior resistance to gap formation, which may occur during postoperative rehabilitation. With equal repair strength, but less soft tissue devitalization, the PARS may be a favorable option for patients with risk factors for soft tissue complications.

The Relationship Between Preoperative Opioid Use and Adverse Events Following Total Knee Arthroplasty.

This study aims to compare perioperative events following total knee arthroplasty (TKA) amongst various degrees of preoperative opioid use. In total, 84,569 patients undergoing TKA were identified from a Humana Claims Dataset, and stratified by their preoperative opioid use based on number of prescriptions filled within 6 months of surgery (naïve 0 [50,561]; sporadic 1 [12,411]; chronic 2 or greater [21,687]). Outcomes of interest included Center for Medicare and Medicaid Services (CMS)-reportable complications, need for postoperative supplemental oxygen, 90-day readmission, and hospital length of stay. Complication rates (9.8% vs 8.9% vs 12.6%; p < 0.01), need for supplemental oxygen (3.0% vs 3.1% vs 5.3%; p = 0.03), mean length of stay (2.1 vs 2.8 vs 3.5; p < 0.01), and 90-day readmission (9.7% vs 10.8% vs 16.4%; p < 0.01) significantly differed amongst groups. On logistic regression, only the chronic opioid use group was associated with significantly increased likelihood of complications, need for supplemental oxygen, and readmission. (Journal of Surgical Orthopaedic Advances 31(2):100-103, 2022).

Risk Factors for Prolonged Opioid Use After Open Treatment of Distal Radius Fractures.

BACKGROUND: The objective of this study was to evaluate factors associated with postoperative opioid use after open treatment of distal radius fractures. METHODS: The Humana insurance claims database was queried for open treatment of distal radius fractures by Current Procedural Terminology codes. The search was further refined to identify patients who filled an opioid prescription within 6 weeks after their surgery. The study's outcomes were: (1) limited postoperative opioid use, defined as filling a prescription once in the 6-week to 6-month period after surgery; and (2) persistent postoperative opioid use, defined as filling a prescription more than once in the 6-week to 6-month period after surgery. Logistic regression models were performed to identify factors associated with limited and persistent postoperative opioid use. Subgroup analyses were performed among opioid-naïve patients and those with open fractures. RESULTS: This study identified 9141 of 19 220 total patients with limited and persistent opioid use. Significant risk factors included nonhome discharge, inpatient surgical setting, long-term pain, tobacco abuse, and age less than 65 years. Of note, both preoperative opioid use within 1 month before surgery (odds ratio [OR], 2.6; 95% confidence interval [CI], 2.2-2.9) and preoperative opioid use between 1 and 6 months before surgery (OR, 4.0; 95% CI, 3.7-4.4) were significantly associated with persistent postoperative opioid use. CONCLUSIONS: This study has identified numerous risk factors associated with postoperative opioid use after open treatment of distal radius fractures. Understanding these risk factors is the first step toward reducing postoperative opioid use.

Triceps Rupture and Repair in a Healthy, Young Woman following Rock Climbing.

Triceps tendon rupture in females is rare. In this case report, we present a young adult female patient with a distal triceps tendon rupture from bouldering treated with open surgical repair technique using a modified bone tunnel and suture anchor fixation technique. The diagnosis and technique for repair and postoperative rehabilitation are described. A review of the current literature of biomechanical and clinical outcomes of various repair techniques is also presented.

Risk of Infection in Thumb Carpometacarpal Surgery After Corticosteroid Injection.

PURPOSE: The purpose of this study was to determine whether patients who had an intra-articular corticosteroid injection into the thumb carpometacarpal (CMC) joint for the treatment of arthritis within the 3 months before CMC joint arthroplasty or arthrodesis were at increased risk for wound complication/infection and/or repeat surgery for wound complication/infection in comparison with patients who did not receive an injection within 6 months or who received an injection between 3 and 6 months before surgery. METHODS: We identified 5,046 patients in the Humana claims database who underwent surgery for CMC joint arthritis. The patients were stratified into 3 groups: (1) no thumb injection within 6 months of CMC joint surgery, (2) thumb injection between 3 and 6 months before CMC joint surgery, and (3) thumb injection within 3 months before CMC joint surgery. The primary outcome was wound complication/infection within 90 days after surgery. The secondary outcome was repeat surgery for wound complication/infection within 90 days after surgery. Multivariable logistic regression was performed to assess the associations between the timing of injection and wound complication/infection and repeat surgery for wound complication/infection. RESULTS: The rates of wound complication/infection within 90 days after surgery were similar among the 3 study groups. However, patients who received an intra-articular corticosteroid injection within 3 months before surgery had a 2.2 times greater likelihood of repeat surgery for a wound complication/infection compared with patients who did not have an injection within 6 months before surgery. CONCLUSIONS: Patients who receive an intra-articular corticosteroid injection within the 3 months before surgery for CMC joint arthritis may be at increased risk of repeat surgery to treat a wound complication/infection in the 90-day postoperative period. TYPE OF STUDY/LEVEL OF EVIDENCE: Prognostic II.

Suture Tape Augmentation Has No Effect on Anterior Tibial Translation, Gap Formation, or Load to Failure of Anterior Cruciate Ligament Repair: A Biomechanical Pilot Study.

PURPOSE: The purpose of our pilot study was to assess the effect of augmenting anterior cruciate ligament (ACL) repair with suture tape on biomechanical parameters including anterior tibial translation, gap formation, and load to failure. METHODS: Ten fresh-frozen nonpaired cadaveric knees were dissected, and baseline anterior-posterior stability of both ACL-intact and -deficient knees was obtained. The specimens were randomized to undergo ACL repair either with or without suture tape reinforcement, and anterior tibial translation, as well as gap formation, was measured after cyclic loading. Finally, all specimens were subjected to a single pullout force to determine maximum load to failure. We performed t test analysis to compare means between groups, and significance was defined as P < .05. RESULTS: On t test analysis, no statistically significant difference was found regarding anterior tibial translation between the ACL-intact group and either repair group or between the repair group without suture tape augmentation and the repair group with suture tape augmentation. No significant difference in gap formation was detected between the repair groups with and without suture tape augmentation at 100 cycles (1.25 mm vs 1.02 mm, P = .6), 250 cycles (2.87 mm vs 2.12 mm, P = .3), and 500 cycles (4.5 mm vs 4.55 mm, P = .5). The average load to failure of the repairs without suture tape augmentation was not significantly different from that of the repairs with suture tape augmentation (725.9 N vs 725.7 N, P = .99). CONCLUSIONS: In this pilot study, we did not identify a difference between ACL repairs with and without suture tape augmentation regarding anterior tibial translation, gap formation, or maximum load to failure. CLINICAL RELEVANCE: Treatment of ACL tears with primary ACL repair is a highly debated topic, and studies such as this study to further our understanding of the biomechanical properties of augmented ACL repairs are important for surgeons when deciding the best treatments for their patients.

Pharmacologic Thromboprophylaxis Other Than Aspirin Is Associated With Increased Risk for Procedural Intervention for Arthrofibrosis After Anterior Cruciate Ligament Reconstruction.

PURPOSE: To compare rates of procedural intervention for arthrofibrosis following anterior cruciate ligament reconstruction (ACLR) among patients who were not prescribed any pharmacologic thromboprophylaxis compared with patients who were prescribed aspirin and to patients who were prescribed other agents. METHODS: A search of a national insurance claims database was performed to identify all patients who underwent ACLR from 2007 to 2017 who were active within the database at a minimum of 6 months before and 18 months after their surgery. The primary outcome studied was a subsequent procedure for arthrofibrosis, manipulation under anesthesia, and lysis of adhesions (MUA/LOA). Patients who filled a prescription for aspirin, low-molecular weight heparin, direct factor Xa inhibitors, fondaparinux, and warfarin within 2 days after their surgery were included and those who filled a prescription within 3 months before surgery were excluded. Thromboprophylaxis status was defined as no thromboprophylaxis, aspirin, and any agent other than aspirin. Logistic regression analysis was performed to determine the association between prophylaxis status and MUA/LOA. RESULTS: Of the 14,081 patients in our final surgical population, 191 patients had MUA/LOA and 13,890 patients did not. In total, 499 patients were prescribed pharmacologic prophylaxis. Rates of MUA/LOA across groups were 1.3% in the group with no thromboprophylaxis, 1.9% in the group prescribed aspirin, and 4.3% in the group prescribed any agent other than aspirin. Only the group prescribed an agent other than aspirin was significantly associated with subsequent procedure for arthrofibrosis (odds ratio 2.6, 95% confidence interval 1.3-4.8, P = .004). CONCLUSIONS: Patients who were prescribed a pharmacologic agent other than aspirin had a 2.6 times greater likelihood of requiring a procedural intervention for arthrofibrosis following ACLR compared with patients who were not prescribed a thromboprophylaxis agent LEVEL OF EVIDENCE: III, Retrospective Cohort Study.

Is average club head speed a risk factor for lower back injuries in professional golfers? A retrospective case control study.

BACKGROUND: Our hypothesis was that higher average club head speed is correlated with lower back injuries in professional golfers. METHODS: This was a retrospective case control study of male professional golfers who suffered lower back injuries while playing golf. The injured group was composed of 14 Professional Golfers' Association (PGA) golfers who withdrew from a PGA tour event due to a back injury during the years 2017-2019. The case-control matching procedure was used to randomly match cases and controls with a 2:1 allocation ratio, respectively, based on age. Variables were chosen based on currently proposed risk factors. Data was statistically analyzed using SPSS 25. RESULTS: There were 14 PGA golfers who suffered lower back injuries during the years 2017-2019 who were included in this study. There was no significant difference in age, height, weight or BMI between the injured and control group. The injured group had a higher mean club head speed than the control group (P < 0.01). CONCLUSION: This study found that average club head speed was significantly higher in PGA golfers who suffered back injuries while golfing during a two-year period (2017-2019) when compared with age-matched controls.

Playing Rule Article Eight Decreases the Rate of Sport Related Concussion in NFL Players Over Two Seasons.

OBJECTIVES: The objectives of this study were to determine if rule article 8 significantly reduced (1) the rate of concussions sustained by NFL players during regular season games, (2) the average games missed secondary to concussion injury, and (3) the number of players placed on the injury reserve for sport-related concussions (SRC). METHODS: This study was a retrospective review of all NFL players who were placed on the publically available injury reports for a concussion from the 2016-2017 to 2019-2020 regular seasons. Player's date of injury was cross-referenced with an absence of statistics from the respective games for which they were ruled out to ensure accuracy. With article 8 taking effect starting with the 2018-2019 season, players were assigned to a pre- or postrule cohort based on date of injury for purposes of injury rate comparison. Injury rates were calculated per 1000 athletic exposures (AE). Relative risk (RR) with 95% confidence intervals (CI) compared injury rates between the two cohorts. Average number of games missed and number of players placed on injury reserve (IR) per year were also calculated. Continuous variables were statistically compared using two-tailed t-test, while categorical variables were compared using Chi-squared test. Statistical significance was set at P ≤ 0.05. RESULTS: There was a 40% decrease in the SRC rate when comparing the post- to the pre-article-8 cohort (3.3 vs 5.5/1000 AEs, respectively; RR 0.60; 95% CI 0.50-0.73). There was no significant difference in average games missed per concussion or percentage of players placed on the IR due to SRC between the two cohorts. CONCLUSIONS: The rate of SRC over the past two NFL seasons following the enactment of playing rule article 8 has significantly decreased when compared with the two seasons prior. The average games missed per concussion and the number of players placed on the IR due to SRC has not significantly changed under playing rule article 8.

Complication rates following hip arthroscopy in the ambulatory surgical center.

There has been an increase in the number of hip arthroscopy procedures performed in the outpatient setting. The purpose of this study was to query a national database to compare post-operative adverse events between hip arthroscopy procedures performed in hospital based outpatient departments (HOPD) versus ASC's. The Humana Claims Database was queried for all patients undergoing hip arthroscopy performed between 2007 and 2016, using the PearlDiver supercomputer. The study population was divided into two cohorts based on the surgical setting, ASC or HOPD. Complications of interest occurring within 90 days after surgery included Center for Medicare and Medicaid Services (CMS)-reportable complications, readmission, and return to the operating room. Visits to the emergency department after 7 days of surgery was also studied. Univariate comparisons between ASC and HOPD groups were drawn with chi-square tests for categorical variables and t-tests for continuous variables. Logistic regression models were created to determine the association between surgical setting and primary outcomes. Rates of 90-day CMS-reportable complications (2.95% vs 2.17%%; p = 0.193), 90-day readmission (4.95% vs 4.25%; p = 0.370) and return to the operating room within 90 days (0.07% vs 0.2%; p = 0.286) were not significantly different between groups. Rate of visits to the emergency department within 7 days was not statistically different between groups (2.57% vs 3.03%; p = 0.458). With the ASC group as reference, no statistically significant association between an outcome and surgical setting was detected after adjusting for confounding factors including comorbidity burden. These findings provide reassurance to providers who perform these procedures in either surgical setting.

National trends, 90-day readmission and subsequent knee surgery following multi-ligament knee reconstruction.

INTRODUCTION/BACKGROUND: Given the uncommon nature of the multi-ligament injured knee, a better understanding of its outcomes may be achieved by contemporary evaluation of a national administrative database. We aim to identify risk factors for 90-day major complications, 90-day readmissions, and subsequent knee surgery after a multi-ligament knee reconstruction. METHODS: The Humana Claims Database was queried for all patients undergoing a multi-ligament knee reconstruction procedure from 2007 to 2016 using International Classification of Diseases (ICD)-9 procedure codes and Current Procedural Terminology (CPT) codes. Outcomes of interest included Center of Medicaid and Medicare Services (CMS)- reportable 90-day complications, 90-day readmission and subsequent ligament reconstruction or total knee arthroplasty. Predictive factors studied included demographics (ie. age, sex, tobacco use) comorbidity burden and operative factors (ie. surgical setting, diagnosis of knee dislocation, concomitant meniscal repair or meniscectomy). RESULTS: 588 multi-ligament knee reconstruction procedures were identified. The 90-day readmission rate 8.3%. The rate of subsequent ligament surgery was 7.1%. On multivariate regression analysis, a diagnosis of knee dislocation was associated with a four times greater likelihood of readmission and a two and a half greater likelihood of subsequent ligament surgery. Concomitant meniscectomy was associated with higher likelihood of subsequent total knee arthroplasty (9.1, 1.4-67.0) and outpatient setting of surgery compared to inpatient hospital setting was associated with reduced likelihood of readmission. CONCLUSION: While uncommon, the patient population undergoing multi-ligament knee surgery is relatively diverse. Understanding common factors predisposing this population to adverse events following surgery may assist in improved outcomes.

Superior Capsule Reconstruction With Subacromial Allograft Spacer: Biomechanical Cadaveric Study of Subacromial Contact Pressure and Superior Humeral Head Translation.

PURPOSE: To investigate the biomechanical effects of superior capsule reconstruction with subacromial allograft spacer on superior humeral head translation and subacromial contact pressure. METHODS: Eight cadaveric shoulder specimens were tested in 4 conditions: (1) intact rotator cuff, (2) supraspinatus tear and superior capsule excision, (3) superior capsule reconstruction with human dermal allograft, and (4) superior capsule reconstruction with subacromial resurfacing using human dermal allograft. In each condition, specimens were tested at 0, 30, 60, and 90° of shoulder abduction in balanced and unbalanced loaded states for subacromial contact pressure and superior humeral head translation. Statistical comparisons were made using a repeated-measures analysis of variance test, followed by a Tukey post hoc test for pairwise comparisons. A P value <.05 was set as statistically significant. RESULTS: Superior humeral head translation and subacromial contact pressure were increased after irreparable rotator cuff tear (P = .001). There was no significant difference between superior capsule reconstruction and intact cuff in regard to superior humeral head translation and subacromial contact pressure at all abduction angles. Superior capsule reconstruction with subacromial resurfacing decreased superior humeral head translation relative to intact (0°, P = .004; 30°, P = .02; 60°, P = .08; 90°, P = .01), superior capsule reconstruction (0°, P = .001; 30°, P = .003; 60°, P = .019; 90°, P = .001), and cuff-deficient states (P = .001). Superior capsule reconstruction with subacromial resurfacing resulted in nonsignificant increases in subacromial contact pressure relative to intact cuff at 0 to 90° abduction angles. CONCLUSIONS: Superior capsule reconstruction with subacromial resurfacing using human dermal allograft results in decreased superior humeral head translation relative to superior capsule reconstruction with human dermal allograft only, while increasing subacromial contact pressure. CLINICAL RELEVANCE: Superior capsule reconstruction with subacromial resurfacing using human dermal allograft reduces superior humeral head translation while increasing subacromial contact pressure in a cadaveric model.

Orthopaedic Shoulder Surgery in the Ambulatory Surgical Center: Safety and Outcomes.

PURPOSE: To determine whether the risk of adverse events and readmission after non-arthroplasty shoulder surgery is influenced by the outpatient setting of surgical care and to identify risk factors associated with these adverse events. METHODS: The Humana Claims Database was queried for all patients undergoing arthroscopic shoulder surgery and related open procedures in the hospital-based outpatient department (HOPD) or ambulatory surgical center (ASC) setting, using the PearlDiver supercomputer. Arthroplasty procedures were excluded because they carry a risk profile different from that of other outpatient surgical procedures. Outcome variables included unanticipated admission after surgery, readmission, deep vein thrombosis, pulmonary embolism, and wound infection within 90 days of surgery. The ASC and HOPD cohorts were propensity score matched, and outcomes were compared between them. Finally, logistic regression models were created to identify risk factors associated with unplanned admission after surgery. RESULTS: A total of 84,658 patients met the inclusion criteria for the study: 28,730 in the ASC cohort and 56,819 in the HOPD cohort. The rates of all queried outcomes were greater in the HOPD cohort and achieved statistical significance. Sex, region, race, insurance status, comorbidity burden, anesthesia type, and procedural type were included in the regression analysis of unplanned admission. Factors associated with unplanned admission included increasing Charlson Comorbidity Index (odds ratio [OR], 1.16; 95% confidence interval [CI], 1.12-1.17; P < .001); HOPD service location (OR, 2.37; 95% CI, 2.18-2.58; P < .001); general anesthesia (OR, 1.34; 95% CI, 1.08-1.59; P = .008); male sex (OR, 2.58; 95% CI, 2.17-3.15; P = .007); and open surgery (OR, 2.35; 95% CI, 1.90-2.61; P < .001). CONCLUSIONS: The lower rates of perioperative morbidity in the ASC cohort suggest that proper patient selection is taking place and lends reassurance to surgeons who are practicing or are considering practicing in an ASC. Patients to whom some or all the risk factors for unplanned admission apply (male sex, higher comorbidity burden, open surgery) may be more suitable for HOPDs because admission from an ASC can be difficult and potentially unsafe. LEVEL OF EVIDENCE: Level III, comparative study.

The effect of surgical setting on anterior cruciate ligament reconstruction outcomes.

Objective: Ambulatory surgical centers (ASC's) have emerged as an alternative to the traditional hospital- based outpatient department (HOPD). We aim to determine the effect of surgical setting on adverse events following anterior cruciate ligament reconstruction (ACLR).Methods: The Humana Claims Database was queried for all patients undergoing ACLR in the HOPD or ASC setting, using the PearlDiver supercomputer. To eliminate selection bias in our study, the HOPD and ASC cohorts were propensity score matched on baseline demographics, comorbidities, and operative factors. Comparisons between the matched cohorts were made using chi-square tests. Logistic regression models were created to determine the effect of surgical setting on adverse events.Results: A total of 13,647 patients were queried in our study, 5,298 of whom underwent surgery in an ASC and 8,349 of whom underwent surgery in an HOPD. Analysis of the post-matched cohort revealed no differences between cohorts for mechanical failure, nerve injury, pulmonary embolism, septic joint, wound infection, revision surgery and readmission. Rates of deep vein thrombosis (1.18% vs 1.84%; p = .03) were significantly lower in the ASC group. On logistic regression, ASC was associated with decreased risk for deep vein thrombosis (.87, .83-.93) and pulmonary embolism (.85, .78-.95).Conclusion: ACLR performed in ASC is associated with reduced risk of venous thromboembolism and no difference in surgical morbidity and readmissions versus ACLR performed in HOPD. Development of a standardized algorithm for patient selection in the ASC setting is needed to preserve acceptability of ASC-based ACLR in cost-savings and patient safety models.

Anatomic Considerations in the Lateral Transpsoas Interbody Fusion: The Impact of Age, Sex, BMI, and Scoliosis.

STUDY DESIGN: This is a retrospective case series. OBJECTIVE: Define the anatomic variations and the risk factors for such within the operative corridor of the transpsoas lateral interbody fusion. SUMMARY OF BACKGROUND DATA: The lateral interbody fusion approach has recently been associated with devastating complications such as injury to the lumbosacral plexus, surrounding vasculature, and bowel. A more comprehensive understanding of anatomic structures in relation to this approach using preoperative imaging would help surgeons identify high-risk patients potentially minimizing these complications. MATERIALS AND METHODS: Age-sex distributed, naive lumbar spine magnetic resonance imagings (n=180) were used to identify the corridor for the lateral lumbar interbody approach using axial images. Bilateral measurements were taken from L1-S1 to determine the locations of critical vascular, intraperitoneal, and muscular structures. In addition, a subcohort of scoliosis patients (n=39) with a Cobb angle >10 degrees were identified and compared. RESULTS: Right-sided vascular anatomy was significantly more variant than left (9.9% vs. 5.7%; P=0.001). There were 9 instances of "at-risk" vasculature on the right side compared with 0 on the left (P=0.004). Age increased vascular anatomy variance bilaterally, particularly in the more caudal levels (P≤0.001). A "rising-psoas sign" was observed in 26.1% of patients. Bowel was identified within the corridor in 30.5% of patients and correlated positively with body mass index (P<0.001). Scoliosis increased variant anatomy of left-sided vasculature at L2-3/L3-4. Nearly all variant anatomy in this group was found on the convex side of the curvature (94.2%). CONCLUSIONS: Given the risks and complications associated with this approach, careful planning must be taken with an understanding of vulnerable anatomic structures. Our analysis suggests that approaching the intervertebral space from the patient's left may reduce the risk of encountering critical vascular structures. Similarly, in the setting of scoliosis, an approach toward the concave side may have a more predictable course for surrounding anatomy. LEVEL OF EVIDENCE: Level 3-study.