United States Experience With a Femoral Neck Retaining Total Hip Arthroplasty Stem: A Retrospective Study With Control Comparison From the Literature.

BACKGROUND: Femoral neck retaining prostheses have gained popularity in Europe, but the United States has not seen the same trends occurring. Previous reports demonstrate high survivorship for these implants, but to our knowledge, there are no reports examining US data. METHODS: After institutional review board approval, 824 primary total hip arthroplasties utilizing a femoral neck-retaining prosthesis were examined for femoral component survivorship rates. European studies were systematically reviewed to determine survivorship rates. The data were used to formulate a Kaplan-Meier survivorship curve and compare US data to that of the European studies. RESULTS: European studies demonstrated survivorship rates for all causes of 97.7 and 99.0% for aseptic loosening at an average of 6 years (range, 4.5 to 10). The current study demonstrated an all-cause 94% Kaplan-Meier survivorship estimate at 5 years and when aseptic loosening only was considered, survivorship increased to 99.4% at 5 years and 98.4% at 11 years. CONCLUSION: This femoral neck-retaining prosthesis demonstrated excellent survivorship that is comparable to the rates seen in European studies as well as the rates of standard and mid-stem prostheses in the United States.

Spinal Versus General Anesthesia for Outpatient Total Hip and Knee Arthroplasty in the Ambulatory Surgery Center: A Matched-Cohort Study.

BACKGROUND: Spinal anesthesia is the predominant regimen in outpatient total joint arthroplasty (TJA), but induction often is unsuccessful, unobtainable, or against patient preference. We compared outcomes of same-day discharge (SDD) TJA with spinal versus general anesthesia in a free-standing ambulatory surgery center (ASC). METHODS: We took 105 general anesthesia TJA and one-to-one nearest-neighbor matched them to 105 spinal anesthesia TJA over 7 years at 1 ASC. The rate of successful SDD, minutes to discharge, postoperative pain and nausea, and 90-day complications were compared. Postanesthesia care unit outcomes were additionally stratified by spinal anesthetic (mepivacaine versus bupivacaine). RESULTS: All spinal anesthetic patients underwent SDD compared with 103 (98%) general anesthetic patients (P = .498). Mepivacaine spinal anesthesia patients spent the fewest minutes in postanesthesia care unit prior to discharge from the facility (206), followed by general anesthesia (227), and bupivacaine spinal anesthesia (291; P < .001). General anesthesia patients had the highest levels of pain at 1 hour (5.2 versus 1.5 versus 1.5) and 2 hours (3.2 versus 2.0 versus 1.3) postoperatively, and rates of nausea (48 versus 22 versus 28%) compared with mepivacaine and bupivacaine spinal anesthesia, respectively. The 90-day complications (6 versus 7), admissions (1 versus 3), and reoperations (5 versus 2) were similar among spinal and general anesthesia, respectively (P ≥ .445). CONCLUSIONS: Both spinal and general anesthesia led to reliable SDD with similar 90-day complication rates. General anesthesia facilitated faster discharge from the ASC compared with bupivacaine spinal anesthesia but led to higher levels of pain and incidence of nausea postoperatively. LEVEL OF EVIDENCE: Level 3, Retrospective Cohort Comparison.

Hip Arthroplasty Femoral Stem Designs and Their Association With Early Postoperative Periprosthetic Femoral Fractures.

BACKGROUND: Periprosthetic femoral fractures (PFFs) in total hip arthroplasty (THA), especially those in contact with the diaphyseal stem, carry high morbidity. This study evaluated how stem design influences the risk of early Vancouver B PFF or other PFF requiring operative intervention after THA. METHODS: A multicenter, retrospective study of 3,433 primary cementless THAs performed from 2014 to 2021 included 2,302 single-taper (micro M/L [n = 1,169]; M/L [n = 1,133]) and 1,131 double-taper (fit-and-fill [n = 420]; compaction-collared [n = 711]) stems. Mean follow-up was 2.2 years (range, 0.3 to 6.5 years). Primary outcomes were Vancouver B and surgically treated postoperative PFFs among differing femoral stems. Secondary outcomes included rates of intraoperative and postoperative Vancouver A and C PFFs. RESULTS: Forty five postoperative PFFs (1.3%) occurred within 8.8 weeks (median), 25 of which were Vancouver B (0.7%) and 20 total PFFs that required operative intervention (0.6%). Compaction-collared stems had a decreased risk of Vancouver B (hazard ratio 0.18, 95% confidence interval: 0.03-0.97 P = .044) and any surgically treated PFF (hazard ratio 0.10, 95% confidence interval: 0.01-0.95; P = .037). Intraoperative PFFs were most common with fit-and-fill stems (3.6%, P < .001) and Vancouver A with compaction-collared stems (1.8%, P < .001). The cohort with PFF had a higher Charlson comorbidity index (P = .004), more women (P = .001), more Dorr A or C femora (P = .013), and more posterior or lateral surgical approaches compared to those without PFF (P ≤ .001). CONCLUSION: After controlling for confounding variables, compaction-collared stems had a significantly lower risk of postoperative Vancouver B and PFF requiring operative treatment than single-taper and double-taper stems.

Safety and short-term outcomes of anatomic vs. reverse total shoulder arthroplasty in an ambulatory surgery center.

BACKGROUND: A scarcity of literature exists comparing outcomes of outpatient anatomic (aTSA) and reverse total shoulder arthroplasty (rTSA). This study was performed to compare early outcomes between the 2 procedures in a freestanding ambulatory surgery center (ASC) and to determine if the addition of preoperative interscalene nerve block (ISNB) with periarticular liposomal bupivacaine injection (PAI) in the postanesthesia care unit (PACU) would improve outcomes over PAI alone. METHODS: Medical charts of all patients undergoing outpatient primary aTSA or rTSA at 2 ASCs from 2012 to 2020 were reviewed. A total of 198 patients were ultimately identified (117 aTSA and 81 rTSA) to make up this retrospective cohort study. Patient demographics, PACU outcomes, complications, readmissions, reoperations, calls to the office, and unplanned clinic visit rates were compared between procedures. PACU outcomes were compared between those receiving ISNB with PAI and those receiving PAI alone. RESULTS: Patients undergoing rTSA were older (61.1 vs. 55.7 years, P < .001) and more likely to have American Society of Anesthesiologists (ASA) class 3 (51.9% vs. 41.0%, P = .050) compared to patients having aTSA. No patient required an overnight stay. Time in the PACU before discharge (89.1 vs. 95.6 minutes, P = .231) and pain scores at discharge (3.0 vs. 3.0, P = .815) were similar for aTSA and rTSA, respectively. One intraoperative complication occurred in the aTSA group (posterior humeral circumflex artery injury) and 1 in the rTSA group (calcar fracture) (P = .793). Ninety-day postoperative total complication (7.7% vs. 7.4%), shoulder-related complication (6.0% vs. 6.2%), medical-related complication (1.7% vs. 1.2%), admission (0.8% vs. 2.5%), reoperation (2.6% vs. 1.2%), and unplanned clinic visit (6.0% vs. 6.1%) rates were similar between aTSA and rTSA, respectively (P ≥ .361 for all comparisons). At 1 year, there were 8 reoperations and 15 complications in the aTSA group compared with 1 reoperation and 8 complications in the rTSA group (P = .091 and P = .818, respectively). Patients who had ISNB spent less time in PACU (75 vs. 97 minutes, P < .001), had less pain at discharge (0.2 vs. 3.9, P < .001), and consumed less oral morphine equivalents in the PACU (1.2 vs. 16.6 mg, P < .001). CONCLUSION: Early postoperative outcomes and complication rates were similar between the 2 groups, and all patients were successfully discharged home the day of surgery. The addition of preoperative ISNB led to more efficient discharge from the ASC with less pain in the PACU.

Mepivacaine vs Bupivacaine Spinal Anesthesia in Total Hip Arthroplasty at an Ambulatory Surgery Center.

BACKGROUND: Mepivacaine spinal anesthetic may facilitate more rapid postoperative recovery in joint arthroplasty than bupivacaine. This study compared recovery, pain, and complications between the 2 anesthetics in anterior-approach total hip arthroplasty (THA) at a free-standing ambulatory surgery center (ASC). METHODS: This retrospective cohort study of 282 consecutive patients with mean age 55.7 ± 8.8 years and body mass index 30.6 ± 5.3 who underwent THA at an ASC from November 2018 to July 2020 compares mepivacaine (n = 141) vs bupivacaine (n = 141) spinal anesthesia, a transition made in March 2019. The main outcomes were length of stay in the postoperative unit (post acute care unit) prior to same-day discharge (SDD), time to controlled void, and ambulation. Secondarily, postoperative pain scores (0-10) with morphine equivalents were required and any postoperative complications were compared. RESULTS: Mepivacaine decreased mean post acute care unit stay (4.0 vs 5.7 hours, P < .001), time to void (3.1 vs 4.9 hours, P < .001), and ambulation (3.2 vs 4.5 hours, P < .001). No patients needed urinary catheterization or overnight stay. Two patients in the bupivacaine group had transient neurologic symptoms, consisting of foot drop and spinal headache, compared to none with mepivacaine (P = .498). Mepivacaine patients had increased postoperative pain at 2 hours (1.7 vs 0.9, P < .001), at discharge (1.1 vs 0.5, P = .004), and morphine equivalent doses received (7.8 vs 3.7 mg, P < .001). CONCLUSION: Mepivacaine spinal anesthesia for anterior-approach THA safely facilitated more rapid SDD from the ASC through decreased times to controlled void and ambulation with only minor increase in pain when compared to bupivacaine. LEVEL OF EVIDENCE: Level III - Retrospective comparative cohort study.

Fixed-Bearing Medial Unicompartmental Knee Arthroplasty in Patients Younger Than 55 Years of Age at 4-19 Years of Follow-Up: A Concise Follow-Up of a Previous Report.

BACKGROUND: Unicompartmental knee arthroplasty (UKA) is an effective alternative to total knee arthroplasty (TKA) in isolated unicompartmental disease; however, mid-term to long-term results in young patients are unknown. The purpose of this study is to determine the mid-term outcomes of fixed-bearing medial UKA in patients less than 55 years of age. METHODS: Seventy-seven fixed-bearing medial UKAs in patients less than 55 years of age (mean 49.9, range 38-55) from a previously published report were retrospectively reviewed at a mean follow-up of 11.2 years (range 4.1-19.2). RESULTS: Eleven knees were converted to TKA (14.3%) at 0.7-13.8 years postoperatively. The indications for revision included 7 for unexplained pain (9.1%), 2 for grade 4 arthritic progression (1 isolated lateral and 1 lateral and patellofemoral compartments; 2.6%), 1 for polyethylene wear (1.3%), and 1 for femoral component loosening (1.3%). Predicted survivorship free from component revision was 90.4% (95% confidence interval 86.9-93.9) at 10 years and 75.1% (95% confidence interval 66.2-84.0) at 19 years. The mean Knee Society Score improved from a mean of 51.9-88.6 points (P < .001). Of the 52 knees with 4-year minimum radiographs, 3 (5.8%) developed isolated grade 4 patellofemoral arthritis that was asymptomatic, and no knees had evidence of component loosening or osteolysis. CONCLUSION: Fixed-bearing medial UKA is a durable option for young patients with unicompartmental arthritis, with good clinical outcomes at mid-term follow-up. Unexplained pain was the most common reason for revision to TKA.

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.

Dilute Betadine Lavage Reduces the Risk of Acute Postoperative Periprosthetic Joint Infection in Aseptic Revision Total Knee and Hip Arthroplasty: A Randomized Controlled Trial.

BACKGROUND: The purpose of this randomized, controlled trial is to determine whether dilute betadine lavage compared to normal saline lavage reduces the rate of acute postoperative periprosthetic joint infection (PJI) in aseptic revision total knee (TKA) and hip arthroplasty (THA). METHODS: A total of 478 patients undergoing aseptic revision TKA and THA were randomized to receive a 3-minute dilute betadine lavage (0.35%) or normal saline lavage before surgical wound closure. Fifteen patients were excluded following randomization (3.1%) and six were lost to follow-up (1.3%), leaving 457 patients available for study. Of them, 234 patients (153 knees, 81 hips) received normal saline lavage and 223 (144 knees, 79 hips) received dilute betadine lavage. The primary outcome was PJI within 90 days of surgery with a secondary assessment of 90-day wound complications. A priori power analysis determined that 285 patients per group were needed to detect a reduction in the rate of PJI from 5% to 1% with 80% power and alpha of 0.05. RESULTS: There were eight infections in the saline group and 1 in the betadine group (3.4% vs 0.4%, P = .038). There was no difference in wound complications between groups (1.3% vs 0%, P = .248). There were no differences in any baseline demographics or type of revision procedure between groups, suggesting appropriate randomization. CONCLUSION: Dilute betadine lavage before surgical wound closure in aseptic revision TKA and THA appears to be a simple, safe, and effective measure to reduce the risk of acute postoperative PJI. LEVEL OF EVIDENCE: Level I.

Choices, Compromises, and Controversies in Total Knee Arthroplasty.

Although condylar total knee arthroplasty (TKA) has been performed for almost 40 years, many choices, compromises, and controversies remain. In the effort to provide optimal care and beneficial, enduring treatment for an expanding population of patients with debilitating arthritis of the knee and who are using ever-diminishing provider and financial resources, orthopaedic surgeons must carefully examine the available evidence to determine best practices. First, there is debate as to who should be a candidate for TKA. Beyond the established criteria of disease severity, should all patients who can benefit from TKA undergo the procedure, or should surgeons develop exclusion criteria based on complication risk? Current concepts for identifying and managing modifiable risk factors should be considered. Second, there is debate regarding the choice of TKA versus partial knee arthroplasty to manage unicompartmental arthritis. Third, surgeons continue to debate the ideal implant design for primary condylar TKA, whether to proceed with an anatomic approach of preserving one or both cruciate ligaments or a functional approach of resecting and substituting for the cruciate ligaments in various ways.

Development and Validation of an Evidence-Based Algorithm for Diagnosing Periprosthetic Joint Infection.

BACKGROUND: The guidelines for diagnosis of periprosthetic joint infection (PJI) introduced by the American Academy of Orthopaedic Surgeons served the orthopedic community well. However, they have never been validated and do not account for newer diagnostic modalities. Our aim was to update current guidelines and develop an evidence-based and validated diagnostic algorithm. METHODS: This multi-institutional study examined total joint arthroplasty patients from 3 institutions. Patients fulfilling major criteria for infection as defined by Musculoskeletal Infection Society were considered infected (n = 684). Patients undergoing aseptic revision for a noninfective indication and did not show evidence of PJI or undergo reoperation within 2 years served as a noninfected control group (n = 820). The algorithm was validated on a separate cohort of 422 cases. RESULTS: The first step in evaluating PJI should include a physical examination, followed by serum C-reactive protein, erythrocyte sedimentation rate, and D-dimer. If at least one of these tests are elevated, or if high clinical suspicion exists, joint aspiration should be performed, sending the fluid for a white blood cell count, leukocyte esterase, polymorphonuclear percentage, and culture. Alpha defensin did not show added benefit as a routine diagnostic test. In inconclusive cases, intraoperative findings including gross purulence, histology, and next-generation sequencing or a single positive culture can aid in making the diagnosis. The proposed algorithm demonstrated a high sensitivity (96.9%) and specificity (99.5%). CONCLUSION: This validated, evidence-based algorithm for diagnosing PJI should guide clinicians in the workup of patients undergoing revision arthroplasty and improve clinical practice. It also has the potential to reduce cost.

Primary Total Hip Arthroplasty in Patients Less Than 50 Years of Age at a Mean of 16 Years: Highly Crosslinked Polyethylene Significantly Reduces the Risk of Revision.

BACKGROUND: The purpose of this study is to evaluate clinical and radiographic outcomes of patients less than 50 years of age undergoing primary total hip arthroplasty (THA) at a minimum of 10 years. METHODS: Three hundred nine consecutive THAs performed on 273 patients were reviewed. At a minimum of 10 years, 13 were deceased and 23 were lost to follow-up leaving 273 THAs in 237 patients who were followed for a mean of 16 years (range 10-19.9). The cohort consisted of 116 females (49%) and 121 males (51%), with a mean age of 42.3 years at the time of surgery (range 19-49). The majority of preoperative diagnoses included osteoarthritis in 149 (63%) and avascular necrosis in 55 (23%). Two hundred sixteen had highly crosslinked polyethylene (HXLPE) and 57 had non-HXLPE acetabular liners. The femoral stems were cementless in 98% (266/273) and the acetabular components were cementless in all cases. Femoral head composition was cobalt-chromium in all cases and the majority of sizes in the non-HXLPE cohort were 28 mm (52/57; 91%), while the HXLPE group primarily consisted of 28 mm (141/216; 65%) and 32 mm (74/216; 34%) heads. Analysis involved Kaplan-Meier survivorship with a log-rank test for equivalence, Fisher's exact test for pairwise comparisons, and a paired t-test for Harris Hip Score, with alpha = 0.05 being statistically significant. RESULTS: There were 6 revisions for wear in the non-HXLPE group (10.5%) compared to none in the HXLPE group (P < .001). Similarly, survivorship with revision for any reason as the endpoint at 16 years was significantly higher at 93.0% in the XLPE group (95% confidence interval 88.7-95.7) compared to 85.7% (95% confidence interval 73.5-92.6) in the non-HXLPE group (P = .023). Additional revisions in the HXLPE group included 6 for instability (2.8%), 5 secondary to infection (2.4%), and 3 stem failures (1.4%). Non-wear-related revisions in the non-HXLPE group included 5 due to instability (8.8%) and 3 due to stem failures (5.3%). The mean Harris Hip Scores for the entire cohort improved from a mean of 46.2 points preoperatively to 89.8 points at most recent follow-up (P < .001). CONCLUSION: The use of HXLPE has led to a significant reduction in the risk of failure in patients <50 years old, with over 93% survivorship at 16 years. Instability and infection, however, remain substantial causes of failure. LEVEL OF EVIDENCE: Therapeutic Level III.

External Validity of a New Prediction Model for Patient Satisfaction After Total Knee Arthroplasty.

BACKGROUND: The ability to identify patients at risk of dissatisfaction after total knee arthroplasty (TKA) remains elusive. This study's purpose was to determine the external validity of a recently published prediction model for patient satisfaction (PMPS) with the hypothesis that it would achieve similar predictive success in our study sample. METHODS: A 10-question PMPS statistically derived from 5 patient-reported outcome questionnaires was tested for external validity in this prospective cohort investigation. The PMPS incorporates gender, age, stiffness, noise, and pain catastrophizing, with a score of 20 or greater predictive of satisfaction. As in the original study, to determine satisfaction the 2011 Knee Society Score (KSS) satisfaction subscale was collected at 3 months postoperatively. Two hundred seventy-four patients were administered the PMPS preoperatively, and 145 patients completed the KSS at 3 months postoperatively (53.0% response rate; 59% female; age, 64.9; body mass index, 32.5). A Bland-Altman analysis to assess agreement was performed. RESULTS: One hundred thirty-three patients (91.7%) were satisfied and 12 (8.3%) were dissatisfied based on their postoperative KSS. The mean difference between the PMPS and KSS was 3.6 ± 8, but with a 95% prediction interval of -15.3 to 22.1 signifying almost no correlation. The PMPS did not predict any of the 12 dissatisfied patients postoperatively, and falsely predicted 5 patients to be dissatisfied of which 4 actually had a maximum postoperative KSS of 40. CONCLUSION: A previously published, internally validated 10-question PMPS was unable to predict satisfaction after TKA in our external study sample. This study emphasizes the difficulty of developing a simple, but robust questionnaire that consistently predicts patient satisfaction after TKA.

Utilizing the Time Trade-Off, Standard Gamble, and Willingness to Pay Utility Measures to Evaluate Health-Related Quality of Life Prior to Knee or Hip Arthroplasty.

BACKGROUND: Time trade-off, standard gamble, and willingness to pay assess the number of years, risk of death, and income a patient would give up for perfect health. These questions were used to evaluate the impact knee arthritis, hip arthritis, or failed total knee (TKA) or hip arthroplasty (THA) has on patients' health-related quality of life prior to surgery. METHODS: Three hundred sixty patients including 176 undergoing primary TKA, 127 undergoing primary THA, 31 undergoing revision TKA, and 26 undergoing revision THA were assessed. Time trade-off and standard gamble were converted to utility scores with 1.0 suggesting perfect health and 0 suggesting preference for death rather than living in current state. Willingness to pay is the percentage of yearly income that a patient would pay for perfect health. RESULTS: The mean time trade-off, standard gamble, and willingness to pay scores were 0.74, 0.83, and 0.32 without significant difference between procedures with the numbers available for study (P = .16, .31, and 0.41, respectively). Increasing body mass index was correlated with decreasing time trade-off scores (P = .014). CONCLUSION: Patients scheduled for primary or revision THA and TKA would accept an average 17% risk of death, lose 2.6 years of an additional 10-year life expectancy, and pay 32% of their income for perfect health. The time trade-off (0.74) was similar to patients with history of acute myocardial infarction (0.74) or minor stroke (0.72) and worse than those with chronic hepatitis C (0.83) or human immunodeficiency virus/acquired immunodeficiency syndrome infection (0.86). These data highlight the high value that patients place on adult reconstructive procedures.

Physical Therapy on Postoperative Day Zero Following Total Knee Arthroplasty: A Randomized, Controlled Trial of 394 Patients.

BACKGROUND: Surgeons have increasingly emphasized early mobilization as a way to facilitate discharge following total knee arthroplasty (TKA). The purpose of this study was to determine whether starting formal physical therapy (PT) the afternoon of postoperative day (POD) 0, instead of starting PT the morning of POD 1, could shorten hospital length of stay (LOS). METHODS: Patients undergoing elective TKA with a planned minimum 1-night hospital stay were randomized to start formal PT the afternoon following surgery or the morning of POD 1. LOS in hours was the primary outcome. An a priori sample size calculation suggested that 394 patients were required to show a 4-hour difference between groups. RESULTS: Out of 394 patients enrolled and randomized, 378 (95.9%) completed the study. The observed difference in hospital LOS was not large enough to be of clinical significance (intention-to-treat analysis: median of 32.0 hours for POD 0 PT vs 31.0 hours for POD 1 PT, P = .65; as-treated analysis: median of 31.0 hours for POD 0 PT vs 32.0 hours for POD 1 PT, P = .12). Similarly, the observed differences in satisfaction with inpatient PT (10.0 vs 10.0, P = .77), patient-reported readiness for discharge at time of discharge (10.0 vs 10.0, P = .97), and POD 0 pain (3.3 vs 4.0, P = .79) were not large enough to be of clinical significance. CONCLUSION: While PT on the day of surgery has been suggested as one method to facilitate discharge following TKA, this randomized trial did not demonstrate clinically meaningful differences in hospital LOS or patient satisfaction when PT is initiated on the day of surgery vs on the morning after surgery.

Prospective Validation of a Demographically Based Primary Total Knee Arthroplasty Size Calculator.

BACKGROUND: Preoperative planning for total knee arthroplasty (TKA) is essential for streamlining operating room efficiency and reducing costs. Digital templating and patient-specific instrumentation have shown some value in TKA but require additional costs and resources. The purpose of this study was to validate a previously published algorithm that uses only demographic variables to accurately predict TKA tibial and femoral component sizes. METHODS: Four hundred seventy-four consecutive patients undergoing elective primary TKA were prospectively enrolled. Four surgeons were included, three of which were unaffiliated with the retrospective cohort study. Patient sex, height, and weight were entered into our published Arthroplasty Size Prediction mobile application. Accuracy of the algorithm was compared with the actual sizes of the implanted femoral and tibial components from 5 different implant systems. Multivariate regression analysis was used to identify independent risk factors for inaccurate outliers for our model. RESULTS: When assessing accuracy to within ±1 size, the accuracies of tibial and femoral components were 87% (412/474) and 76% (360/474). When assessing accuracy to within ±2 sizes of predicted, the tibial accuracy was 97% (461/474), and the femoral accuracy was 95% (450/474). Risk factors for the actual components falling outside of 2 predicted sizes include weight less than 70 kg (odds ratio = 2.47, 95% confidence interval [1.21-5.06], P = .01) and use of an implant system with <2.5 mm incremental changes between femoral sizes (odds ratio = 5.50, 95% confidence interval [3.33-9.11], P < .001). CONCLUSIONS: This prospective series of patients validates a simple algorithm to predict component sizing for TKA with high accuracy based on demographic variables alone. Surgeons can use this algorithm to simplify the preoperative planning process by reducing unnecessary trays, trials, and implant storage, particularly in the community or outpatient setting where resources are limited. Further assessment of components with less than 2.5-mm differences between femoral sizes is required in the future to make this algorithm more applicable worldwide.

The James A. Rand Young Investigator's Award: Large Opioid Prescriptions Are Unnecessary After Total Joint Arthroplasty: A Randomized Controlled Trial.

BACKGROUND: The purpose of this randomized controlled trial is to determine whether the quantity of opioid pills prescribed at discharge is associated with the number of opioid pills consumed or unused by patients after primary hip and knee arthroplasty within 30 days after discharge. METHODS: A total of 304 opioid-naïve patients were randomized to receive either 30 or 90 5-mg oxycodone immediate-release (OxyIR) pills at discharge. Daily opioid consumption, number of unused pills, and pain scores were calculated for 30 days with a patient-completed medication diary. Statistical analysis involved t-test, rank-sum, chi-squared tests, and multiple linear regression with alpha = 0.05. RESULTS: Of the 304 patients randomized, 161 patients were randomized to receive 30 pills and 143 to receive 90. In the first 30 days after discharge, the median number of unused pills was 15 in the 30 group vs 73 in the 90 group (P < .001). Within 90 days of discharge, 26.7% of the 30 group and 10.5% of the 90 group requested a refill (P < .001), leading to a mean of 777.1 ± 414.2 morphine equivalents vs 1089.7 ± 536.4 prescribed (P < .0001). There was no difference between groups in mean morphine equivalents consumed. Regression analysis demonstrated that being prescribed 90 OxyIR pills was independently associated with taking more OxyIR pills (P = .028). There was no difference in pain scores within the first 30 days and in patient-reported outcome scores at 6 weeks postoperatively. CONCLUSION: Prescribing fewer OxyIR pills is associated with a significant reduction in unused opioid pills and decreased opioid consumption with no increase in pain scores and no difference in patient-reported outcomes. LEVEL OF EVIDENCE: Level I. Randomized controlled trial.

Total Knee Arthroplasty in Patients Less Than 50 Years of Age: Results at a Mean of 13 Years.

BACKGROUND: Patients between 45 and 54 years old will be the fastest-growing cohort seeking total knee arthroplasty (TKA) over the next 15 years. The purpose of this investigation is to determine the clinical outcomes of TKA in patients less than 50 years old at a minimum of 10 years. We hypothesized that this patient population would have a high rate of survivorship that is similar to that of older patients. METHODS: We reviewed 298 consecutive TKAs on 242 patients at a minimum of 10 years postoperatively. Twenty patients died and 30 TKAs were lost to follow-up leaving 248 TKAs in 202 patients (91 male, 111 female) with a mean age of 45.7 years (range, 26-49) at the time of surgery. Patient-reported outcomes, survivorship, causes of reoperation, and initial postoperative radiographic parameters were collected. RESULTS: At a mean of 13.0 years, there were 9 revisions for tibial loosening (3.6%), 8 for deep infection (3.2%), 7 for polyethylene wear (2.8%), and 3 for failed ingrowth of a cementless femoral component (1.2%). Kaplan-Meier analysis demonstrated 92.0% survivorship with failures defined as aseptic component revision and 83.9% survivorship for all-cause reoperation at 13 years. Patients with tibial alignment of 4° or more of varus or 10° or more of posterior slope were found to have increased rate of failure. CONCLUSION: While overall durability was good in this young patient population, tibial fixation and deep infection were relatively common causes of failure. In addition, increased tibial varus and slope were found to increase the rate of failure. Furthermore, the nearly 3% risk of revision for wear suggests that the use of more wear-resistant bearing surfaces may reduce the risk of failure in this patient population.

Diagnosing Taper Corrosion: When Is It the Taper and When Is It Something Else?

There has been an increasing use of modularity at the head-neck junction in total hip arthroplasty to more closely mimic the native anatomy, allowing for optimal leg length and stability. Corrosion at this junction in metal-on-polyethylene bearings can lead to an adverse local tissue reaction (ALTR). This increasingly prevalent condition should be considered in the differential diagnosis of hip pain and difficulty ambulating. A recent symposium by the American Academy of Hip and Knee Surgeons described the diagnosis, etiology, management, and prevention of taper corrosion. This article describes the history, physical, plain and advanced imaging findings, laboratory tests, and other diagnoses that should be taken into consideration when diagnosing taper corrosion. The presence of ALTR due to taper corrosion can mimic other diagnoses such as periprosthetic joint infection, instability, or aseptic loosening. Serum metal levels have been found to be the most effective screening tool for identifying corrosion, but other common causes of hip pain and difficulty ambulating should always be ruled out with the use of radiographs and common laboratory techniques before diagnosing ALTR due to corrosion.

Inpatient Versus Outpatient Hip and Knee Arthroplasty: Which Has Higher Patient Satisfaction?

BACKGROUND: More surgeons are offering patients the option of having adult reconstructive procedures performed as an outpatient at an ambulatory surgery center. However, it is unknown if these patients have higher or lower satisfaction with their care than patients having a traditional inpatient stay. The purpose of this study is to compare satisfaction between inpatients and outpatients undergoing hip or knee arthroplasty. METHODS: Portions of the Health Consumer Assessment of Healthcare Providers and Systems survey, the Friends and Family Test, and 8 additional questions were administered to 174 consecutive patients. There were 8 non-responders (95.4% response rate) leaving 102 who underwent inpatient and 64 who had outpatient surgery. Responses were stratified using the "boxes" scoring approach as recommended by Health Consumer Assessment of Healthcare Providers and Systems and analyzed with a chi-squared or Fischer's exact test where appropriate. Power analysis determined that 38 patients per group were needed to detect a 1-point difference in overall satisfaction between groups with 80% power and alpha of 0.05 considered significant. RESULTS: Outpatients responded with more top responses when asked about the staff's explanation of any medicines received (91.4% vs 77.5%, P = .026), the staff's assistance with their pain management (98.3% vs 88.0%, P = .022), the written health information they were given upon discharge (98.3% vs 90.1%, P = .05), and the courtesy and respect from the nurses (100.0% vs 92.2%, P = .022). Inpatients responded with more bottom responses when asked how prepared they felt for discharge home (8.9% vs 0.0%, P = .014). Top responses in overall satisfaction with the facility (87.1% vs 93.4%, P = .204) and overall experience (89.2% vs 95.2%, P = .177) were similar between inpatients and outpatients, respectively. Not surprisingly, inpatients were older (64.1 vs 59.2 years, P = .001), heavier (body mass index 32.7 vs 30.4, P = .035), and had higher Charlson comorbidity scores (2.6 vs 1.9, P = .002). CONCLUSION: Although satisfaction was high in both groups, when differences were present they favored outpatient surgery in the ambulatory surgery center.

The Alpha-Defensin Test for Diagnosing Periprosthetic Joint Infection in the Setting of an Adverse Local Tissue Reaction Secondary to a Failed Metal-on-Metal Bearing or Corrosion at the Head-Neck Junction.

BACKGROUND: In patients with adverse local tissue reaction (ALTR) secondary to a failed metal-on-metal (MoM) bearing or corrosion at the head-neck junction in a metal-on-polyethylene bearing, ruling in or out periprosthetic joint infection (PJI) can be challenging. Alpha-defensin has emerged as an accurate test for PJI. The purpose of this multicenter, retrospective study was to evaluate the accuracy of the alpha-defensin synovial fluid test in detecting PJI in patients with ALTR. METHODS: We reviewed medical records of 26 patients from 3 centers with ALTR that had an alpha-defensin test performed. Patients were assessed for PJI using the Musculoskeletal Infection Society criteria. Thirteen of these subjects had MoM total hip arthroplasty, 9 had ALTR secondary to head-neck corrosion, and 4 had MoM hip resurfacing. RESULTS: Only 1 of the 26 patients met Musculoskeletal Infection Society criteria for infection. However, 9 hips were alpha-defensin positive, including 1 true positive and 8 that were falsely positive (31%). All 8 of the false positives were also Synovasure positive, although 5 of 8 had an accompanying warning stating the results may be falsely positive due to a low synovial C-reactive protein value. CONCLUSION: Similar to synovial fluid white blood cell count, alpha-defensin testing is prone to false-positive results in the setting of ALTR. Therefore, we recommend an aggressive approach to ruling out PJI including routine aspiration of all hips with ALTR before revision surgery to integrate the synovial fluid blood cell count, differential, cultures and adjunctive tests like alpha-defensin to allow for accurate diagnosis preoperatively.