Patient-Reported Outcomes of Total Hip Arthroplasty at an Ambulatory Surgery Center Versus a Hospital-Based Center.

INTRODUCTION: The utilization of ambulatory surgery centers (ASCs) and same-day discharge (SDD) from hospital-based centers (HBCs) after total hip arthroplasty (THA) continues to increase. There remains a paucity of literature directly comparing patient-reported outcomes by surgery site. We sought to compare outcomes between patients undergoing THA at an ASC versus HBC while controlling for medical comorbidities. METHODS: Patients undergoing primary THA with SDD (postoperative day 0) from a single HBC (1,015 patients) or stand-alone ASC (170 patients) from December 2020 to 2021 were identified. Patient demographics, comorbidities, and 90-day complications were collected. Hip Osteoarthritis Outcome Score (HOOS JR), VR-12, and procedural satisfaction scores were collected preoperatively and at 3, 6, and 12 months. Patients were matched by age and American Society of Anesthesiologists (ASA). Chi-squared analysis was conducted to compare categorical variables, and a Wilcoxon rank-sum test was used for continuous variables. Linear regression models were conducted considering age, sex, and presence of comorbidities. RESULTS: Patients undergoing THA at an ASC had markedly higher VR-12 Physical Component Scores at all time points and improved VR-12 Mental Component Scores at preoperative visit and 6 months. These patients had increased procedural satisfaction at 3 months, although there was no difference at 1 year. No notable difference was observed in 90-day complication rates between groups. After matching by age and ASA, each group had 170 patients. In the matched analysis, preoperative HOOS JR scores were markedly lower in the HBC group. However, there was no notable difference in HOOS JR scores, change in HOOS JR scores, and procedural satisfaction, at any postoperative time point. CONCLUSIONS: No notable difference was observed in patient-reported outcomes at any time point for SDD after THA performed at an ASC or an HBC when controlling for age and comorbidities. This study suggests noninferiority of stand-alone ASCs for outpatient THA, regarding patient satisfaction and patient-reported outcomes.

Alignment is only part of the equation: High variability in soft tissue distractibility in the varus knee undergoing primary TKA.

PURPOSE: The purpose of this study is to evaluate the in vivo medial and lateral joint laxities across various total knee arthroplasty (TKA) alignment categories correlated to (1) hip-knee-ankle angle, (2) proximal tibial angle and (3) distal femoral angle in a consecutive group of patients undergoing robotic-assisted TKA. METHODS: Using ligament tensions acquired during 805 robotic-assisted TKA with a dynamic ligament tensor under a load of 70-90 N, the relationship between medial and lateral collateral ligament laxity and overall limb alignment was established. Only knees with neutral or mechanical varus alignment were included and divided into five groups: neutral (0°-3°), varus 3°-5°, varus 6°-9°, varus 10°-13° and varus ≥14°. Groups were further subdivided by the intraoperative medial proximal tibial angle (MPTA) and lateral distal femoral angle (LDFA). The distraction of the medial and lateral sides was compared across the various alignments using an analysis of variance. RESULTS: The ability to distract the medial collateral ligament in extension and flexion was proportional to the degree of varus deformity, increasing from 4.0 ± 2.3 mm in the neutral group to 8.7 ± 3.2 mm in the varus ≥14° group (p < 0.0001). On the lateral side, the distraction of the lateral collateral ligament decreased in both extension (2.2 ± 2.4 vs. 1.2 ± 2.7, p < 0.0001) and flexion (2.8 ± 2.8 to 1.7 ± 3.0, p < 0.0001) with increasing native varus deformity. MPTA and LDFA had similar effects, where increasing MPTA varus and LDFA valgus increased medial distractibility in extension and flexion. There was significant variability of the stretch of the ligaments within and across all alignment categories, in which the standard deviation of the groups ranged from 2.0 to 3.0 mm. CONCLUSION: This study demonstrates increased medial ligament distractibility with increasing varus deformity. However, there was significant variability in ligamentous laxity within various limb alignment categories suggesting the anatomy and soft tissue identity of the knee is complex and highly variable. TKAs seeking to be more anatomic will not only need to restore alignment but also native soft tissue tensions. LEVEL OF EVIDENCE: Level III, prognostic.

Development and Validation of a Risk Calculator for Intensive Care Unit Admission After Total Hip Arthroplasty.

BACKGROUND: The purpose of this study was to develop and validate a risk stratification calculator to determine the risk of a patient requiring intensive care unit (ICU) admission following primary and revision total hip arthroplasty (THA). METHODS: Using a database of 12,342 THA procedures, with 132 ICU admissions, from 2005 to 2017, we developed models of ICU admission risk based on previously identified preoperative factors including age, heart disease, neurologic disease, renal disease, unilateral versus bilateral surgery, preoperative hemoglobin, blood glucose, and smoking status. Prior to developing the calculator, a set of logistic regressions were analyzed to determine weight and scoring for each variable. Once developed, we validated the risk calculator using a second independent institution. RESULTS: A separate risk calculator was developed for primary and revision THA. The area under the curve (AUC) for primary THA was 0.808 (95% confidence interval 0.740 to 0.876) and revision THA was AUC 0.795 (confidence interval 0.740 to 0.850). As an example, the primary THA risk calculator had a Total Points scale of 220, with 50 points associated with a 0.1% chance of ICU admission and 205 points associated with a 95% chance of ICU admission. Validation with an external cohort demonstrated satisfactory AUCs, sensitivities, and specificities for both primary THA (AUC 0.794, sensitivity 0.750, and specificity 0.722) and revision THA (AUC 0.703, sensitivity 0.704, and specificity 0.671) CONCLUSION: The externally validated risk calculators developed in this study can accurately predict ICU admission following primary and revision THA based on a number of readily available preoperative factors.

Increased Cup Anteversion May Not Prevent Posterior Dislocation in Patients With Abnormal Spinopelvic Characteristics in Total Hip Arthroplasty.

Background: The aims of this study were to (1) assess the degree of variation in acetabular component placement and combined anteversion in a large cohort of dislocating total hip arthroplasties; (2) assess the spinopelvic characteristics of the cohort; and (3) examine the association between cup anteversion and reported direction of instability. Methods: A commercial database of 245 dislocating total hip arthroplasties referred for postoperative computed tomography and functional radiographic imaging and analysis were reviewed. Spinopelvic parameters and cup and stem positions were measured in the supine, standing, flex-seated, and anterior pelvic plane (APP) positions. Spinopelvic characteristics were stratified by high, neutral, and low cup anteversion using thresholds of >35° and <15° anteversion in standing, respectively. Results: In the dislocation cohort, 62%, 45%, and 42% of cups were within the safe zone in supine, standing, and the APP, respectively (P < .001). Patients with high vs neutral or low cup anteversion had significantly stiffer spines, more posterior pelvic tilt in standing, greater changes in pelvic tilt, and higher sagittal imbalance. Of the 45 patients with high cup anteversion and reported instability direction, 60% and 40% were reported to have posterior and anterior instability, respectively, with no differences in spinopelvic characteristics. Conclusions: In this dislocating cohort, there is a decreased percentage of cups within the safe zone in the APP and standing position compared to the supine reference. In addition, we found that patients having poor spinopelvic characteristics and high cup anteversion can still dislocate, suggesting that adjusting cup anteversion alone may not be sufficient for preventing instability.

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.

No Benefit to Sensor-guided Balancing Compared With Freehand Balancing in TKA: A Randomized Controlled Trial.

BACKGROUND: Soft tissue balancing in TKA has traditionally relied on surgeons' subjective tactile feedback. Although sensor-guided balancing devices have been proposed to provide more objective feedback, it is unclear whether their use improves patient outcomes. QUESTIONS/PURPOSES: We conducted a randomized controlled trial (RCT) comparing freehand balancing with the use of a sensor-guided balancing device and evaluated (1) knee ROM, (2) patient-reported outcome measures (PROMs) (SF-12, WOMAC, and Knee Society Functional Scores [KSFS]), and (3) various surgical and hospital parameters (such as operative time, length of stay [LOS], and surgical complications) at a minimum of 2 years of follow-up. METHODS: A total of 152 patients scheduled for primary TKA were recruited and provided informed consent to participate in this this study. Of these, 22 patients were excluded preoperatively, intraoperatively, or postoperatively due to patient request, surgery cancellation, anatomical exclusion criteria determined during surgery, technical issues with the sensor device, or loss to follow-up. After the minimum 2-year follow-up was accounted for, there were 63 sensor-guided and 67 freehand patients, for a total of 130 patients undergoing primary TKA for osteoarthritis. The procedures were performed by one of three fellowship-trained arthroplasty surgeons (RPS, HJC, JAG) and were randomized to either soft tissue balancing via a freehand technique or with a sensor-guided balancing device at one institution from December 2017 to December 2018. There was no difference in the mean age (72 ± 8 years versus 70 ± 9 years, mean difference 2; p = 0.11), BMI (30 ± 6 kg/m 2 versus 29 ± 6 kg/m 2 , mean difference 1; p = 0.83), gender (79% women versus 70% women; p = 0.22), and American Society of Anesthesiology score (2 ± 1 versus 2 ± 1, mean difference 0; p = 0.92) between the sensor-guided and freehand groups, respectively. For both groups, soft tissue balancing was performed after all bony cuts were completed and trial components inserted, with the primary difference in technique being the ability to quantify the intercompartmental balance using the trial tibial insert embedded with a wireless sensor in the sensor-guided cohort. Implant manufacturers were not standardized. Primary outcomes were knee ROM and PROMs at 3 months, 1 year, and 2 years. Secondary outcomes included pain level evaluated by the VAS, opioid consumption, inpatient physical therapy performance, LOS, discharge disposition, surgical complications, and reoperations. RESULTS: There was no difference in the mean knee ROM at 3 months, 1 year, and 2 years postoperatively between the sensor-guided cohort (113° ± 11°, 119° ± 13°, and 116° ± 12°, respectively) and the freehand cohort (116° ± 13° [p = 0.36], 117° ± 13° [p = 0.41], and 117° ± 12° [p = 0.87], respectively). There was no difference in SF-12 physical, SF-12 mental, WOMAC pain, WOMAC stiffness, WOMAC function, and KSFS scores between the cohorts at 3 months, 1 year, and 2 years postoperatively. The mean operative time in the sensor-guided cohort was longer than that in the freehand cohort (107 ± 0.02 versus 84 ± 0.04 minutes, mean difference = 23 minutes; p = 0.008), but there were no differences in LOS, physical therapy performance, VAS pain scores, opioid consumption, discharge disposition, surgical complications, or percentages of patients in each group who underwent reoperation. CONCLUSION: This RCT demonstrated that at 2 years postoperatively, the use of a sensor-balancing device for soft tissue balancing in TKA did not confer any additional benefit in terms of knee ROM, PROMs, and clinical outcomes. Given the significantly increased operative time and costs associated with the use of a sensor-balancing device, we recommend against its routine use in clinical practice by experienced surgeons. LEVEL OF EVIDENCE: Level I, therapeutic study.

Preoperative Anemia Is Associated With 30-Day Morbidity in Total Knee Arthroplasty.

Given the heightened focus on decreasing length of stay and readmissions following total joint arthroplasty, meticulous preoperative optimization has become increasingly important. The goal of this study was to evaluate the association between preoperative anemia and postoperative morbidity and mortality at 30 days. We used the National Surgical Quality Improvement Program database to identify patients who underwent primary total knee arthroplasty (TKA) between 2006 and 2016. Cohorts were defined based on preoperative hemoglobin and were evaluated for 30-day complications as well as 30-day readmission and non-home discharge. The survey of the National Surgical Quality Improvement Program database yielded 198,233 patients who underwent TKA between 2006 and 2016. Preoperative anemia was found to be a risk factor for all complications (4.73% vs 3.22%, P<.001) as well as non-home discharge (37.0% vs 24.2%, P<.001) and unplanned readmission (4.99% vs 3.14%, P<.001) using both bivariate analysis and multivariate analysis. Meticulous optimization of patients at risk for complications is critical in the era of bundled care and increased focus on rapid transition from inpatient to outpatient care. Preoperative anemia was associated with the total postoperative complication rate at 30 days following TKA as well as non-home discharge and unplanned readmission. Surgeons should attempt to identify patients with preoperative anemia and correct underlying low blood levels to help minimize the rate of postoperative complications. [Orthopedics. 2022;45(2):e86-e90.].

Short-Term Outcomes Are Comparable between Robotic-Arm Assisted and Traditional Total Knee Arthroplasty.

Robotic-arm assisted total knee arthroplasty (rTKA) was developed to provide for increased accuracy of component placement compared with conventional manual TKA (mTKA). Whether or not rTKA is cost-effective in a bundled payment model has yet to be addressed. The purpose of this comparative study was to evaluate the short-term clinical outcomes of rTKA and mTKA. We retrospectively reviewed a series of 4,086 consecutive primary TKA performed by one of five surgeons across six different hospitals at our institution from January 2016 to December 2018. Outcomes for rTKA cases (n = 581) and mTKA cases (n = 3,505) were compared using unmatched multivariate analysis and a matched cohort. We analyzed 90-day outcomes, episode-of-care claims data, and short form (SF-12) outcome scores to 2 years postoperatively. In matched bivariate analysis, there was no difference in episode-of-care costs, postacute care costs, complications, 90-day readmission rates, emergency department/urgent care visits, reoperations, and mortality between rTKA and mTKA patients (p > 0.05). Matched patients undergoing rTKA did have a shorter hospital length of stay (1.46 vs. 1.80 days, p < 0.001) and decreased rates of discharge to rehabilitation facilities (5.5 vs. 14.8%, p < 0.001). SF-12 scores were clinically similar. Multivariate analysis demonstrated no differences in any 90-day outcome. We conclude that patients undergoing rTKA have comparable costs, 90-day outcomes, and clinically similar improvements in functional outcome scores compared with mTKA patients. Further study is needed to determine whether rTKA will result in improved implant survivorship and long-term functional outcomes (Level of evidence III).

Effect of femoral head material on head-to-trunnion impaction motion and taper.

The purpose of this study was to evaluate the effect of femoral head material on the impaction force, relative motion, and stability of the trunnion. There were three groups with different head materials (n = 5 per group)-CoCr Group: 36 mm CoCr heads, Ceramic Group: 36 mm ceramic heads, Ceramic + Sleeve Group: 36 mm ceramic heads with a titanium sleeve-that were all impacted twice and disengaged onto titanium alloy (Ti6al4V) trunnions in in vitro conditions. A high-speed camera system was utilized to characterize relative displacement behavior of the head-trunnion junction motion. The first impact force of Ceramic + Sleeve Group (14,241 SD, 935) was significantly lower than the first impact force in Ceramic Group (14,961 N, SD = 184). Ceramic + Sleeve Group had a lower magnitude bounce-back displacement following the first impact (17.7 µm, SD = 11), p < 0.05) compared to CoCr Group (298.8 µm, SD = 84) and Group 2 (196.5 µm, SD = 31). Ceramic + Sleeve Group sat further on the trunnion (cumulative final displacement, 366.8 µm, SD = 71, p < 0.001) compared to CoCr Group (142.5 µm, SD = 41.8) and Ceramic Group (183.8 µm, SD = 30). Ceramic + Sleeve Group demonstrated two distinct disengagement patterns-(a) the sleeve disengaged from the trunnion (pull-off force 6810 N), and (b) the femoral head disengaged from the sleeve (pull-off force 18,620 N), with large fluctuations in pull-off force. The presence of a titanium sleeve with a ceramic head resulted in significant differences in impaction force on the trunnion, motion and displacement, and unique mechanisms for disengagement. Further investigation is required to determine potential clinical impact.

What is the Level of Evidence Substantiating Commercial Payers' Coverage Policies for Total Joint Arthroplasty?

BACKGROUND: The prevalence of total joint arthroplasty (TJA) in the United States has drawn the attention of health care stakeholders. The payers have also used a variety of strategies to regulate the medical necessity of these procedures. The purpose of this study was to examine the level of evidence of the coverage policies being used by commercial payers in the United States. METHODS: The references of the coverage policies of four commercial insurance companies were reviewed for type of document, level of evidence, applicability to a TJA population, and success of nonoperative treatment in patients with severe degenerative joint disease. RESULTS: 282 documents were reviewed. 45.8% were primary journal articles, 14.2% were level I or II, 41.2% were applicable to patients who were candidates for TJA, and 9.9% discussed the success of nonoperative treatment in patients who would be candidates for TJA. CONCLUSION: Most of the references cited by commercial payers are of a lower level of scientific evidence and not applicable to patients considered to be candidates for TJA. This is relatively uniform across the reviewed payers. The dearth of high-quality literature cited by commercial payers reflects the lack of evidence and difficulty in conducting high level studies on the outcomes of nonoperative versus operative treatment for patients with severe, symptomatic osteoarthritis. Patients, surgeons, and payers would all benefit from such studies and we encourage professional societies to strive toward that end through multicenter collaboration.