Fretting and Tribocorrosion of Modular Dual Mobility Liners: Role of Design, Microstructure, and Malseating.

BACKGROUND: Modular dual mobility (DM) bearings have a junction between a cobalt chrome alloy (CoCrMo) liner and titanium shell, and the risk of tribocorrosion at this interface remains a concern. The purpose of this study was to determine whether liner malseating and liner designs are associated with taper tribocorrosion. METHODS: We evaluated 28 retrieved modular DM implants with a mean in situ duration of 14.6 months (range, 1 to 83). There were two manufacturers included (12 and 16 liners, respectively). Liners were considered malseated if a distinct divergence between the liner and shell was present on postoperative radiographs. Tribocorrosion was analyzed qualitatively with the modified Goldberg Score (mGS) and quantitatively with an optical coordinate-measuring machine. An acetabular shell per manufacturer was sectioned for metallographic analysis. RESULTS: There were six implants (22%) that had severe grade 4 corrosion, six (22%) had moderate grade 3, 11 (41%) had mild grade 2, and five (18.5%) had grade 1 or no visible corrosion. The average volumetric material loss at the taper was 0.086 ± 0.19 mm3. There were seven liners (25%) that had radiographic evidence of malseating, and all were of a single design (P = 0.01). The two liner designs were fundamentally different from one another with respect to the CoCrMo alloy type, taper surface finish, and shape deviations. Malseating was an independent risk factor for increased volumetric material loss (P = 0.017). CONCLUSION: Dual mobility tribocorrosion with quantifiable material loss occurred more commonly in malseated liners. Specific design characteristics may make liners more prone to malseating, and the interplay between seating mechanics, liner characteristics, and patient factors likely contributes to the shell/liner tribocorrosion environment.

The Ideal Timing of Bilateral Total Knee Arthroplasty: Simultaneous Versus Staged.

Objectives: The ideal timing for patients undergoing bilateral total knee arthroplasty (TKA) remains unknown. The purpose of this study was to compare 90-day outcomes between unilateral, simultaneous bilateral, and staged bilateral TKA. Methods: The PearlDiver database was used to retrospectively identify 231,119 patients undergoing primary TKA during 2015-2020, of which 67,956 (29.4%) were bilateral. Bilateral TKA patients were divided into cohorts of simultaneous bilateral TKA and staged bilateral TKA at 1-14 days, 15-30 days, 31-90 days, and 91-365 days. Each bilateral TKA cohort underwent one-to-one matching with unilateral TKA patients based on age, gender, year, Elixhauser Comorbidity Index (ECI), and a history of obesity, diabetes, and tobacco use. Ninety-day outcomes were compared between matched groups via univariate and multivariate analysis. In staged bilateral TKA groups, outcomes were collected beginning after the second TKA. Results: Compared to unilateral TKA, simultaneous bilateral TKA was associated with higher rates of venous thromboembolism (VTE; odds ratio [OR] 1.28, 95% confidence interval [CI] 1.07-1.54, p=0.007), acute kidney injury (AKI; OR 1.47, CI 1.17-1.84, p=0.001), blood transfusion (OR 6.81, CI 5.43-8.65, p<0.001), and any complication (OR 1.63, CI 1.49-1.78, p<0.001). Staged bilateral TKA at any time interval studied was associated with a similar or decreased risk of individual complications, emergency department visits, readmissions, reoperations, and any complication relative to unilateral TKA. Conclusion: Simultaneous bilateral TKA is associated with an increased risk of adverse events compared to unilateral TKA. However, bilateral TKA staged at a short interval appears safe in appropriately selected patients.

Dual-Mobility versus Large Femoral Heads in Revision Total Hip Arthroplasty: Interim Analysis of a Randomized Controlled Trial.

BACKGROUND: This multicenter randomized controlled trial evaluated if dual-mobility bearings (DM) lower the risk of dislocation compared to large femoral heads (≥36 mm) for patients undergoing revision total hip arthroplasty (THA) via a posterior approach. METHODS: A total of 146 patients were randomized to a DM (n = 76; 46 mm median effective head size, range 36 to 59 mm) or a large femoral head (n = 70; twenty-five 36 mm heads [35.7%], forty-one 40 mm heads [58.6%], and four 44 mm heads [5.7%]). There were 71 single-component revisions (48.6%), 39 both-component revisions (26.7%), 24 reimplantations of THA after 2-stage revision (16.4%), seven isolated head and liner exchanges (4.8%), four conversions of hemiarthroplasty (2.7%), and 1 revision of a hip resurfacing (0.7%). Power analysis determined that 161 patients were required in each group to lower the dislocation rate from 8.4 to 2.2% (power = 0.8, alpha = 0.05). RESULTS: At a mean of 18.2 months (range, 1.4 to 48.2), there were three dislocations in the large femoral head group compared to two in the DM cohort (4.3 versus 2.6%; P = .67). One patient in the large head group and none in the DM group were successfully treated with closed reduction without subsequent revision. CONCLUSION: Interim analysis of this randomized controlled trial found no difference in the risk of dislocation between DM and large femoral heads in revision THA, although the rate of dislocation was lower than anticipated and continued follow-up is needed.

Cementless Total Knee Arthroplasty is Associated With Early Aseptic Loosening in a Large National Database.

BACKGROUND: Despite excellent longevity demonstrated in institutional studies, outcomes after cementless total knee arthroplasty (TKA) on a population level remain unknown. This study compares 2-year outcomes between cemented and cementless TKA using a large national database. METHODS: A large national database was used to identify 294,485 patients undergoing primary TKA from January 2015 to December 2018. Patients who had osteoporosis or inflammatory arthritis were excluded. Cementless and cemented TKA patients were matched one-to-one based on age, Elixhauser Comorbidity Index, sex, and year yielding matched cohorts of 10,580 patients. Outcomes at 90 days, 1 year, and 2 years postoperatively were compared between groups, and Kaplan-Meier analysis was used to evaluate implant survival rates. RESULTS: At 1 year postoperatively, cementless TKA was associated with an increased rate of any reoperation (odds ratio [OR] 1.47, 95% confidence interval [CI] 1.12-1.92, P = .005) compared to cemented TKA. At 2 years postoperatively, there was an increased risk of revision for aseptic loosening (OR 2.34, CI 1.47-3.85, P < .001) and any reoperation (OR 1.29, CI 1.04-1.59, P = .019) after cementless TKA. Two-year revision rates for infection, fracture, and patella resurfacing were similar between cohorts. CONCLUSION: In this large national database, cementless fixation is an independent risk factor for aseptic loosening requiring revision and any reoperation within 2 years after primary TKA.

Short-Term Indwelling Foley Catheters Do Not Reduce the Risk of Postoperative Urinary Retention in Uncomplicated Primary THA and TKA: A Randomized Controlled Trial.

BACKGROUND: The purpose of this randomized controlled trial was to determine whether a short-term Foley catheter (inserted in the operating room and removed upon arrival to the orthopaedic floor) would reduce the risk of postoperative urinary retention (POUR) in patients undergoing primary total hip (THA) and total knee arthroplasty (TKA). METHODS: Three hundred and eighty-eight patients undergoing inpatient primary TKA (n = 228) or THA (n = 160) with spinal anesthesia were randomized to receive a short-term Foley catheter (n = 194) or no Foley (n = 194). There were 143 male and 245 female patients. The primary outcome was POUR, defined as requiring ≥2 straight catheterizations or the placement of an indwelling urinary catheter when indicated by retention of ≥450 mL on bladder scans. Secondary outcomes included urinary tract infections (UTIs) within 3 weeks and the need for ≥1 straight catheterization. A power analysis determined that 194 patients per group were required to detect a 7% minimal clinically important difference in POUR rates at 80% power and alpha of 0.05. Intention-to-treat and as-treated analyses were performed (2 patients received the non-allocated treatment). Outcomes were compared between the groups using univariate and multivariate analyses, with alpha < 0.05. RESULTS: Nine patients developed POUR: 4 in the short-term Foley group and 5 in the control group (2.1% versus 2.6%; p = 1.00). Of those who developed POUR, 8 were male and 1 was female (88.9% versus 11.1%; p = 0.002). Twenty-four patients required ≥1 straight catheterization: 10 in the Foley group and 14 in the control group (5.2% versus 7.2%; p = 0.40). Four patients developed UTIs: 3 in the Foley group and 1 in the control group (1.5% versus 0.5%; p = 0.62) on intention-to-treat analysis, and 4 in the Foley group and none in the control group (2.1% versus 0.0%; p = 0.12) on as-treated analysis. CONCLUSIONS: The use of a short-term Foley catheter inserted in the operating room and removed on arrival to the orthopaedic floor does not decrease the rate of POUR. LEVEL OF EVIDENCE: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Contralateral Total Hip Arthroplasty Staged Within Six Weeks Increases the Risk of Adverse Events Compared to Unilateral Surgery.

BACKGROUND: The ideal timing for bilateral total hip arthroplasty (THA) remains controversial. This study compared 90-day outcomes after simultaneous bilateral THA and contralateral surgery in staged bilateral THA to a matched cohort of unilateral procedures. METHODS: Patients undergoing primary, elective THA during 2015 to 2020 were reviewed in a national database. Of the 273,281 patients identified, 39,905 (14.6%) were bilateral. Patients were divided into cohorts of unilateral THA, simultaneous bilateral THA, and staged bilateral THA at 1 to 14 days, 15 to 42 days, 43 to 90 days, and 91 to 365 days. Bilateral THA cohorts were matched with unilateral THA patients based on demographics and comorbidities. Ninety-day outcomes after the second THA were compared between matched groups. RESULTS: Simultaneous bilateral THA resulted in higher rates of transfusion (odds ratio [OR] 4.43, 95% confidence interval 2.31-2.63, P < .001), readmission (OR 2.60, 2.01-3.39, P < .001), and any complication (OR 1.86, 1.55-2.24, P < .001) compared to unilateral THA. Contralateral THA staged at 1 to 14 days increased the risk of readmission (OR 1.83, 1.49-2.24, P < .001) and any complication (OR 1.45, 1.26-1.66, P < .001) relative to unilateral THA. Contralateral THA staged at 15 to 42 days increased the risk of periprosthetic joint infection (OR 3.15, 1.98-5.19, P < .001), readmission (OR 1.92, 1.55-2.39, P < .001), and any complication (OR 1.70, 1.46-1.97, P < .001). Contralateral THA staged beyond 42 days resulted in similar or decreased rates of adverse events relative to unilateral THA. CONCLUSIONS: Bilateral THA should be staged a minimum of 6 weeks apart in appropriately selected patients to avoid an increased risk of adverse events after the second THA compared to unilateral THA.

Vitamin D3 Supplementation Prior to Total Knee Arthroplasty: A Randomized Controlled Trial.

BACKGROUND: The purpose of this randomized controlled trial was to determine if a one-time dose of vitamin D3 prior to total knee arthroplasty improves function and patient-reported outcomes, while decreasing complications. METHODS: One hundred seven patients undergoing primary total knee arthroplasty were randomized to receive 50,000 international units vitamin D3 (57 patients) or placebo (50 patients) on the morning of surgery. Power analysis determined 45 patients were required in each cohort to detect a minimal clinically important difference of 6 points in the functional component of the 2011 version of the Knee Society Score (KSS), assuming an alpha of 0.05 and power of 80%. KSS and a Timed Up and Go Test (TUGT) were measured preoperatively and at 3 and 6 weeks postoperatively. RESULTS: There was no difference in improvement of KSS at 3 weeks (+4.8 points vitamin D3 versus +3.0 points placebo; P = .6) or 6 weeks (+14.5 points vitamin D3 versus +12.4 points placebo; P = .5) from baseline. There was no difference in change in TUGT at 3 weeks (+1.2 seconds vitamin D3 versus +0.6 seconds placebo; P = .6) or 6 weeks (-0.3 seconds vitamin D3 versus -0.9 seconds placebo; P = .6) from baseline. There were 4 complications in the placebo cohort within the first 90 days postoperatively and 5 complications in the vitamin D3 cohort (P = 1.0). CONCLUSION: Supplementation with 50,000 international units vitamin D3 on the day of surgery failed to demonstrate statistical significant differences in functional KSS, TUGT times, or complications in the early postoperative period compared to placebo. LEVEL OF EVIDENCE: Level I, therapeutic study.

Distal Femoral Replacement for Fractures Allows for Early Mobilization with Low Complication Rates: A Multicenter Review.

Periprosthetic fractures around a total knee arthroplasty (TKA), comminuted and intra-articular femur fractures, or fracture nonunions in osteoporotic bone represent technically challenging problems. This is particularly true when the fracture involves a loose femoral component or the pattern results in suboptimal fixation potential. These clinical indications often arise in an older and comorbid patient population in whom a principal goal of treatment includes allowing for early mobilization. Limited data indicate that arthroplasty via distal femoral replacement (DFR) is a reasonable alternative to open reduction and internal fixation, allowing for early ambulation with low complication rates. We performed a retrospective review of trauma and arthroplasty surgeries at three tertiary referral institutions. Adult patients treated for the above with a DFR were included. Patients with active infection, open and/or high-energy injuries and revisions unrelated to fracture were excluded. Patient demographics, treatment details, and outcomes were assessed. Between 2002 and 2017, 90 DFR's were performed for the above indications with a mean follow-up of 24 months. Postoperatively, 80 patients (88%) were allowed to weight bear as tolerated, and at final follow-up, 9 patients (10%) remained dependent on a wheelchair. The average arc of motion at final follow-up was 95 degrees. There were seven (8%) implant-related complications requiring secondary surgeries: two infections, one with associated component loosening; one fracture of the hinge mechanism and one femoral component failure in conjunction with a patellofemoral dislocation (both requiring revision); one case of patellofemoral arthrosis in a patient with an unresurfaced patella; one periprosthetic fracture with associated wound dehiscence; and one case of arthrofibrosis. In each of these cases, only modular components of the DFR were exchanged. All nonmodular components cemented into the femur or tibia were retained. DFR provides a viable reconstruction option in the treatment of acute distal femur fractures, periprosthetic femur fractures, and fracture nonunions. We noted that in an elderly patient population with high comorbidities, the complication and secondary surgery rates remained relatively low, while allowing for immediate weight bearing.

Mid-Term Performance of the First Mass-Produced Three-Dimensional Printed Cementless Tibia in the United States as Reported in the American Joint Replacement Registry.

BACKGROUND: Cementless tibial components have shown improvements in clinical performance compared to predicate designs, though evidence supporting mid-term performance and fixation is scarce. The purpose of this study is to determine the mid-term survivorships, revision rates, and reasons why 3-dimensional printed cementless tibial baseplates (3DTKAs) failed compared to other cementless as well as cemented tibial baseplates reported from the American Joint Replacement Registry (AJRR) data. METHODS: All primary total knee arthroplasty (TKA) cases performed in patients 65 years of age or older within the AJRR from January 2, 2012 through June 30, 2020 were queried. A total of 28,631 3DTKAs were identified from 428 institutions. These were compared to all other "aggregated cementless tibia" (n = 7,577) and "aggregated cemented tibia" (n = 550,133) cases. Centers for Medicare & Medicaid Services data over the same time period were merged with AJRR data to determine survivorship and patient-timed incident revision rates per 1,000 years. Failure reasons were tracked during this study period. RESULTS: At 60 months, Kaplan-Meier implant survivorship was 98.9% (CI 98.7-99.0), 98.3% (CI 97.9-98.6), and 98.4% (CI 98.4-98.5) in the 3DTKA, aggregate cementless, and cemented knee cohorts, respectively (P < .0001). Patient-timed incident revision rates were 3.11 (CI 2.75-3.53), 3.99 (CI 3.34-4.76), and 3.35 (CI 3.28-3.42) for those cohorts, which corresponds to a revision rate of 0.31%, 0.40%, and 0.34% per year. CONCLUSION: In this analysis, 3DTKA had favorable survivorship and lower revision rates compared to aggregate cementless and cemented TKAs implanted from the same national database during the same time period.

Radiographic and clinical analysis of a Porous-coated metaphyseal cone for revision total Knee arthroplasty.

BACKGROUND: The aim of this study was to evaluate the radiographic and clinical outcomes of a recently introduced metaphyseal cone system for revision TKA. METHODS: 73 revision TKAs in 72 patients were retrospectively reviewed. All patients had a minimum of 2-year clinical follow-up (mean 34.1 months; range 24.0 to 50.3 months). 114 Metaphyseal cones (64 tibial and 50 femoral) of a single manufacturer were implanted. The most common indications for revision were aseptic loosening (56.9%), second stage reimplantation for periprosthetic joint infection (PJI; 26.4%), and instability (12.5%). All femoral and tibial stems were press-fit cementless stems. RESULTS: Ten of 72 patients underwent re-revision: six for infection (8.3%), two for instability (2.8%), one (1.4%) for patellar tendon rupture and one (1.4%) for femoral component loosening (a cone was not utilized at index revision). Two patients had loose cones (one with an isolated tibial cone and one with both femoral and tibial cones) associated with loose implants but declined re-revision. Aseptic survivorship of our patient cohort free from any re-revision surgery was 95.9% at 2 years (95% CI 87.4-98.7%) and 96.5% of cones demonstrated radiographic evidence of osseointegration. At 2-years, the Knee Society Score (KSS) improved from a mean of 17.2 points preoperatively to 57.8 points (p <.0001). CONCLUSIONS: Porous-coated metaphyseal cones from this manufacturer demonstrate excellent aseptic survivorship and radiographic evidence of osseointegration similar to prior designs when used with cementless stems.

Malseating of modular dual mobility liners.

AIMS: Prior studies have identified that malseating of a modular dual mobility liner can occur, with previous reported incidences between 5.8% and 16.4%. The aim of this study was to determine the incidence of malseating in dual mobility implants at our institution, assess for risk factors for liner malseating, and investigate whether liner malseating has any impact on clinical outcomes after surgery. METHODS: We retrospectively reviewed the radiographs of 239 primary and revision total hip arthroplasties with a modular dual mobility liner. Two independent reviewers assessed radiographs for each patient twice for evidence of malseating, with a third observer acting as a tiebreaker. Univariate analysis was conducted to determine risk factors for malseating with Youden's index used to identify cut-off points. Cohen's kappa test was used to measure interobserver and intraobserver reliability. RESULTS: In all, 12 liners (5.0%), including eight Stryker (6.8%) and four Zimmer Biomet (3.3%), had radiological evidence of malseating. Interobserver reliability was found to be 0.453 (95% confidence interval (CI) 0.26 to 0.64), suggesting weak inter-rater agreement, with strong agreement being greater than 0.8. We found component size of 50 mm or less to be associated with liner malseating on univariate analysis (p = 0.031). Patients with malseated liners appeared to have no associated clinical consequences, and none required revision surgery at a mean of 14 months (1.4 to 99.2) postoperatively. CONCLUSION: The incidence of liner malseating was 5.0%, which is similar to other reports. Component size of 50 mm or smaller was identified as a risk factor for malseating. Surgeons should be aware that malseating can occur and implant design changes or changes in instrumentation should be considered to lower the risk of malseating. Although further follow-up is needed, it remains to be seen if malseating is associated with any clinical consequences. Cite this article: Bone Jt Open 2021;2(10):858-864.

Early outcomes of a modern cemented total knee arthroplasty : is tibial loosening a concern?

AIMS: Recent total knee arthroplasty (TKA) designs have featured more anatomical morphologies and shorter tibial keels. However, several reports have raised concerns about the impact of these modifications on implant longevity. The aim of this study was to report the early performance of a modern, cemented TKA design. METHODS: All patients who received a primary, cemented TKA between 2012 and 2017 with a minimum two-year follow-up were included. The implant investigated features an asymmetrical tibial baseplate and shortened keel. Patient demographic details, Knee Society Scores (KSS), component alignment, and the presence of radiolucent lines at final follow-up were recorded. Kaplan-Meier analyses were performed to estimate survivorship. RESULTS: A total of 720 of 754 primary TKAs (95.5%) were included with a mean follow-up of 3.9 years (SD 1.3); 562 (78.1%) were cruciate-retaining and 158 (21.9%) were posterior-stabilized. A total of 11 (1.5%) required reoperation for periprosthetic joint infection and seven (1.0%) for aseptic tibial loosening (five cruciate-retaining, two posterior-stabilized). Loosening occurred at a mean of 3.3 years (0.9 to 6.5). There were no cases of loosening in the 33 patients who received a 14 mm × 30 mm tibial stem extension. All-cause survivorship was 96.6% at three years (95% confidence interval (CI) 95.3% to 98.0%) and 96.2% at five years (95% CI 94.8% to 97.7%). Survivorship with revision for aseptic loosening was 99.6% at three years (95% CI 99.1% to 100.0%) and 99.1% at five years (95% CI 98.4% to 99.9%). Tibial components were in significantly more varus in those with aseptic loosening (mean 3.4° (SD 3.7°) vs 1.3° (SD 2.0°); p = 0.015). There were no other differences in demographic, radiological, or surgical characteristics between revised and non-revised TKAs for aseptic loosening (p = 0.293 to 1.00). Mean KSS improved significantly from 57.3 (SD 9.5) preoperatively to 92.6 (SD 8.9) at the final follow-up (p < 0.001). CONCLUSION: This is the largest series to date of this design of implant. At short-term follow-up, the rate of aseptic tibial loosening is not overly concerning. Further observation is required to determine if there will be an abnormal rate of loosening at mid- to long-term follow-up. Cite this article: Bone Joint J 2021;103-B(6 Supple A):51-58.

The Effectiveness of Closed-Incision Negative-Pressure Therapy Versus Silver-Impregnated Dressings in Mitigating Surgical Site Complications in High-Risk Patients After Revision Knee Arthroplasty: The PROMISES Randomized Controlled Trial.

BACKGROUND: Revision total knee arthroplasty (rTKA) is associated with significant risk of wound-related morbidity. The present study aimed to evaluate the 1) efficacy of closed-incision negative-pressure therapy (ciNPT) vs silver-impregnated antimicrobial dressing (AMD) in mitigating postoperative surgical site complications (SSCs), 2) the effect of ciNPT vs AMD on certain postoperative health utilization parameters, and on 3) patient-reported outcomes (PROs) improvement at 90-day postoperative follow-up. METHODS: This multicenter randomized controlled trial was conducted between December 2017 and August 2019. Patients ≥22 years, at high risk for SSC, and receiving rTKA with full exchange and reimplantation of new prosthetic components or open reduction and internal fixation of periprosthetic fractures were screened for inclusion. Eligible patients were randomized to receive a commercially available ciNPT system or a silver-impregnated AMD (n = 147, each) for minimum of 5-day duration. Primary outcome was the 90-day incidence of SSCs with stratification in accordance with revision type (aseptic/septic). Secondary outcomes were the 90-day health care utilization parameters (readmission, reoperation, dressing changes, and visits) and PROs. RESULTS: Of 294 patients randomized (age: 64.9 ± 9.0 years, female: 59.6%), 242 (82.0%) patients completed the study (ciNPT: n = 124; AMD: n = 118). The incidence of 90-day SSCs was lower for the ciNPT cohort (ciNPT: 3.4% vs AMD: 14.3%; odds ratio (OR): 0.22, 95% confidence interval (0.08, 0.59); P = .0013). Readmission rates (3.4% vs 10.2%, OR: 0.30(0.11, 0.86); P = .0208) and mean dressing changes (1.1 ± 0.3 vs 1.3 ± 1.0; P = .0003) were lower with ciNPT. The differences in reoperation rates, number of visits, and PRO improvement between both arms were not statistically significant (P > .05). CONCLUSION: ciNPT is effective in reducing the 90-day postoperative SSCs, readmission, and number of dressing changes after rTKA. Recommending routine implementation would require true-cost analyses.

The Optimal Dosing Regimen for Tranexamic Acid in Revision Total Hip Arthroplasty: A Multicenter Randomized Clinical Trial.

BACKGROUND: The purpose of this multicenter, randomized trial was to determine the optimal dosing regimen of tranexamic acid (TXA) to minimize perioperative blood loss in revision total hip arthroplasty. METHODS: Six centers prospectively randomized 175 patients to 1 of 4 regimens: (1) 1-g intravenous (IV) TXA prior to incision (the single-dose IV group), (2) 1-g IV TXA prior to incision followed by 1-g IV TXA after arthrotomy wound closure (the double-dose IV group), (3) a combination of 1-g IV TXA prior to incision and 1-g intraoperative topical TXA (the combined IV and topical group), or (4) 3 doses totaling 1,950-mg oral TXA (the multidose oral group). Randomization was based on revision subgroups to ensure equivalent group distribution. An a priori power analysis (α = 0.05; ß = 0.80) determined that 40 patients per group were required to identify a >1-g/dL difference in postoperative hemoglobin reduction between groups. Per-protocol analysis involved an analysis of variance, Fisher exact tests, and two 1-sided t tests for equivalence. Demographic and surgical variables were equivalent between groups. RESULTS: No significant differences were found between TXA regimens when evaluating reduction in hemoglobin (3.4 g/dL for the single-dose IV group, 3.6 g/dL for the double-dose IV group, 3.5 g/dL for the combined IV and topical group, and 3.4 g/dL for the multidose oral group; p = 0.95), calculated blood loss (p = 0.90), or transfusion rates (14% for the single-dose IV group, 18% for the double-dose IV group, 17% for the combined group, and 17% for the multidose oral group; p = 0.96). Equivalence testing revealed that all possible pairings were statistically equivalent, assuming a >1-g/dL difference in hemoglobin reduction as clinically relevant. There was 1 venous thromboembolism, with no differences found between groups (p = 1.00). CONCLUSIONS: All 4 TXA groups tested had equivalent blood-sparing properties in the setting of revision total hip arthroplasty, with a single venous thromboembolism reported in this high-risk population. Based on the equivalence between groups, surgeons should utilize whichever of the 4 investigated regimens is best suited for their practice and hospital setting. Given the transfusion rate in revision total hip arthroplasty despite TXA utilization, further work is required in this area. LEVEL OF EVIDENCE: Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.

The Efficacy and Safety of Opioids in Total Joint Arthroplasty: Systematic Review and Direct Meta-Analysis.

BACKGROUND: Opioids are frequently used to treat pain after total joint arthroplasty (TJA). The purpose of this study was to evaluate the efficacy and safety of opioids in primary TJA to support the combined clinical practice guidelines of the American Association of Hip and Knee Surgeons, American Academy of Orthopaedic Surgeons, Hip Society, Knee Society, and the American Society of Regional Anesthesia and Pain Management. METHODS: The MEDLINE, EMBASE, and Cochrane Central Register of controlled trials were searched for studies published before November 2018 on opioids in TJA. All included studies underwent qualitative and quantitative homogeneity testing followed by a systematic review and direct comparison meta-analysis to assess the efficacy and safety of opioids. RESULTS: Preoperative opioid use leads to increased opioid consumption and complications after TJA along with a higher risk of chronic opioid use and inferior patient-reported outcomes. Scheduled opioids administered preemptively, intraoperatively, or postoperatively reduce the need for additional opioids for breakthrough pain. Prescribing fewer opioid pills after discharge is associated with equivalent functional outcomes and decreased opioid consumption. Tramadol reduces postoperative opioid consumption but increases the risk of postoperative nausea, vomiting, dry mouth, and dizziness. CONCLUSION: Moderate evidence supports the use of opioids in TJA to reduce postoperative pain and opioid consumption. Opioids should be used cautiously as they may increase the risk of complications, such as respiratory depression and sedation, especially if combined with other central nervous system depressants or used in the elderly.

Saline lavage after a "dry tap".

AIMS: In patients with a "dry" aspiration during the investigation of prosthetic joint infection (PJI), saline lavage is commonly used to obtain a sample for analysis. The aim of this study was to investigate prospectively the impact of saline lavage on synovial fluid analysis in revision arthroplasty. METHODS: Patients undergoing revision hip (THA) or knee arthroplasty (TKA) for any septic or aseptic indication were enrolled. Intraoperatively, prior to arthrotomy, the maximum amount of fluid possible was aspirated to simulate a dry tap (pre-lavage) followed by the injection with 20 ml of normal saline and re-aspiration (post-lavage). Pre- and post-lavage synovial white blood cell (WBC) count, percent polymorphonuclear cells (%PMN), and cultures were compared. RESULTS: A total of 78 patients had data available for analysis; 17 underwent revision THA and 61 underwent revision TKA. A total of 16 patients met modified Musculoskeletal Infection Society (MSIS) criteria for PJI. Pre- and post-lavage %PMNs were similar in septic patients (87% vs 85%) and aseptic patients (35% vs 39%). Pre- and post-lavage synovial fluid WBC count were far more disparate in septic (53,553 vs 8,275 WBCs) and aseptic (1,103 vs 268 WBCs) cohorts. At a cutoff of 80% PMN, the post-lavage aspirate had a sensitivity of 75% and specificity of 95%. At a cutoff of 3,000 WBCs, the post-lavage aspirate had a sensitivity of 63% and specificity of 98%. As the post-lavage synovial WBC count increased, the difference between pre- and post-lavage %PMN decreased (mean difference of 5% PMN in WBC < 3,000 vs mean difference 2% PMN in WBC > 3,000, p = 0.013). Of ten positive pre-lavage fluid cultures, only six remained positive post-lavage. CONCLUSION: While saline lavage aspiration significantly lowered the synovial WBC count, the %PMN remained similar, particularly at WBC counts of > 3,000. These findings suggest that in patients with a dry-tap, the %PMN of a saline lavage aspiration has reasonable sensitivity (75%) for the detection of PJI. Cite this article: Bone Joint J 2020;102-B(6 Supple A):138-144.

Education Increases Disposal of Unused Opioids After Total Joint Arthroplasty: A Cluster-Randomized Controlled Trial.

BACKGROUND: Unused opioid pills are a danger to patients and their loved ones as they may be diverted for abuse or misuse. The purpose of this study was to determine the baseline rate of proper disposal of unused opioids among patients undergoing total joint arthroplasty and to determine how education impacts disposal rates. METHODS: In this study, 563 patients undergoing primary total joint arthroplasty (183 patients undergoing total hip arthroplasty, 293 patients undergoing total knee arthroplasty, and 87 patients undergoing unicompartmental knee arthroplasty) were cluster-randomized to groups that received no education, educational pamphlets, or educational pamphlets plus text messages. Patients were randomized by education class and were blinded to participation to avoid behavioral modifications. Patients were surveyed at 6 weeks postoperatively to determine if they disposed of their unused opioid pills using a U.S. Food and Drug Administration-recommended method, which was the primary outcome. Assuming a 15% difference in opioid disposal rates as clinically relevant, power analysis determined that 76 patients with unused opioids were required per group (228 total). An as-treated analysis was conducted with the Fisher exact text and analysis of variance with alpha = 0.05. RESULTS: A total of 539 patients (95.7%) completed the survey, and 342 patients (63.5%) had unused opioid pills at 6 weeks postoperatively: 89 patients in the no education group, 128 patients in the pamphlet group, and 125 patients in the pamphlet and text message group. Of these 342 patients, 9.0% of patients in the no education group, 32.8% of patients in the pamphlet group, and 38.4% of patients in the pamphlet and text message group properly disposed of their unused opioids (p = 0.001 for each educational intervention compared with no education). Unused opioid pills were kept by 82.0% of patients in the no education group, 64.1% of patients in the pamphlet group, and 54.4% of patients in the pamphlet and text message group (p < 0.001 for the no education group compared with either educational strategy group). Patients who underwent total hip arthroplasty were more likely to properly dispose of their unused opioids compared with those who underwent total knee arthroplasty (odds ratio, 2.1; p = 0.005). There were no demographic differences between groups, including inpatient opioid use, refills, and preoperative opioid use, other than sex (41.5% male patients in the no education group, 55.0% male patients in the pamphlet group, and 37.4% male patients in the pamphlet and text message group; p = 0.001), suggesting appropriate randomization. CONCLUSIONS: The rate of opioid disposal is very low after total joint arthroplasty. Education on opioid disposal more than triples opioid disposal rates compared with no education. To help to prevent diversion of unused opioid pills, all patients who undergo total joint arthroplasty should be educated on the proper disposal of unused opioids.

Does Femoral Morphology Predict the Risk of Periprosthetic Fracture After Cementless Total Hip Arthroplasty?

BACKGROUND: Periprosthetic femur fracture remains a leading mode of early failure following cementless total hip arthroplasty (THA). The purpose of this study is to determine if a specific femoral morphology is associated with an increased risk of acute, periprosthetic fracture after cementless THA. METHODS: An institutional arthroplasty registry was used to identify 32 primary, cementless THAs revised for acute, postoperative periprosthetic fracture ("fracture" cohort) within 3 months of the index procedure. Patients were matched 1:2 to 64 THAs without fracture ("control" cohort) for age, body mass index, gender, and stem design. Preoperative radiographic measurements performed on anteroposterior pelvis and femur radiographs included the neck-shaft angle, endosteal width at 4 locations, and external cortical diameter at 2 locations. These measurements were used to calculate the morphological cortical index, canal flare index, canal calcar ratio, and canal bone ratio. Postoperative measurements included canal fill and stem alignment. Statistical analyses included clustered regressions, Fisher's exact test, and Student's t-test. RESULTS: The mean endosteal width at 10 cm distal to the lesser trochanter was greater in fracture patients, although not statistically significant (P = .1). However, this resulted in differences in the canal flare index (P = .03), canal calcar ratio (P = .03), and canal bone ratio (P = .03) between the 2 cohorts. These ratios indicate decreased meta-diaphyseal taper in fracture patients. Preoperative femoral neck-shaft angle was more varus in fracture patients (P = .04). CONCLUSION: Patients sustaining an acute, periprosthetic fracture with cementless femoral fixation after THA had thinner distal cortices and a decreased meta-diaphyseal taper.

Are Postoperative Hip Precautions Necessary After Primary Total Hip Arthroplasty Using a Posterior Approach? Preliminary Results of a Prospective Randomized Trial.

BACKGROUND: It is unclear whether posterior hip precautions after primary total hip arthroplasty (THA) reduce the incidence of early postoperative dislocation. METHODS: We performed a prospective randomized study to evaluate the effect of hip precautions on incidence of early dislocation after primary THA using a posterior approach. Between January 2016 and April 2019, 587 patients (594 hips) were consented and randomized into restricted or unrestricted groups. No significant demographic or surgical differences existed between groups. The restricted group was instructed to refrain from hip flexion >90°, adduction across midline, and internal rotation for 6 weeks. 98.5% (585 of 594) of hips were available for minimum 6-week follow-up (291 restricted and 294 unrestricted). Power analysis showed that 579 hips per group are needed to demonstrate an increase in dislocation rate from 0.5% to 2.5% with 80% power. RESULTS: At average follow-up of 15 weeks (range, 6-88), there were 5 dislocations (incidence, 0.85%). Three posterior dislocations occurred in the restricted group at a mean of 32 days (range, 17-47), and 2 posterior dislocations occurred in the unrestricted group at a mean of 112 days (range, 21-203), with no difference in dislocation rate between groups (1.03% vs 0.68%; odds ratio, 0.658; 95% confidence interval, 0.11-3.96; P = .647). At 6 weeks, unrestricted patients endorsed less difficulty with activities of daily living, earlier return to driving, and more time spent side sleeping (P < .05). CONCLUSION: Preliminary analysis suggests that removal of hip precautions after primary THA using a posterior approach was not associated with early dislocation and facilitated return to daily functions. Investigation to appropriate power is warranted.