What’s New in Adult Reconstructive Knee Surgery

Over the past year, areas of investigation in total knee arthroplasty (TKA) and unicompartmental knee arthroplasty (UKA) such as bleeding control, thromboprophylaxis, pain management, technology-assisted surgery, and infection received major attention. We have included selected studies, many at the highest Levels of Evidence, in an attempt to summarize the most relevant recent findings. Economics of Added Technology Ahmed et al.1 evaluated the adoption of computer-assisted knee arthroplasty between the first quarter of 2010 and the third quarter of 2017 in the states of New York and Florida, making use of 2 statewide administrative databases (the Statewide Planning and Research Cooperative System in New York and the Florida Administrative Data in Florida). The proportion of computer-assisted knee arthroplasty increased from 4.89% to 9.45% in New York, and from 4.03% to 5.73% in Florida. In New York, that represented a 93.3% growth in utilization. One of the reasons preventing the widespread adoption of these new technologies is their increased costs. In a Markov model, Rajan et al.2 ascertained the cost-effectiveness of robotic-assisted TKA compared with conventional TKA. Robotic-assisted TKA produced 13.55 quality-adjusted life-years (QALYs) compared with 13.29 QALYs for conventional TKA. Because of its higher QALYs, robotic-assisted TKA remains cost-effective despite being associated with higher costs as long as annualized revision rates stay <1.6%. The cost-utility of patient-specific instrumentation for TKA compared with the standard of care among patients with a body mass index (BMI) of >30 kg/m2 was evaluated; patient-specific instrumentation was more costly and less effective3. A secondary analysis of a randomized clinical trial (RCT) comparing closed-incision, negative-pressure therapy with the standard of care after revision TKA revealed that the total per-patient costs for surgical-site management were $1,047 for closed-incision, negative-pressure therapy and $2,036 for the standard of care4. Knee Osteoarthritis Genetic markers seem to play a role in advanced knee osteoarthritis. Utilizing clinical and genomic data, investigators showed that age and BMI contributed more to the risk of developing end-stage disease than genetic factors. However, 7 genetic loci were significantly associated with end-stage osteoarthritis. The effects of genetic factors were greater in patients who were <60 years of age5. The use of hyaluronic acid and platelet-rich plasma remains controversial. Among Medicare patients, hyaluronic acid utilization increased from 1,090,503 patients in 2012 to 1,209,489 patients in 2018 (p = 0.04), and total costs related to hyaluronic acid services increased from $290.10 million to $325.02 million (p < 0.01)6. In patients with hemophilic knee arthritis, a trial compared the effects of platelet-rich plasma injections with those of placebo on outcomes over a 24-month follow-up. There were no clinically important differences in the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, the visual analog scale (VAS) for pain, the Hemophilia Joint Health Score, and the Short-Form 36 (SF-36) at any point in time7. UKA UKA Compared with TKA The best surgical treatment option for advanced single-compartment knee osteoarthritis is still debated. In an RCT, patient-reported outcome measures (PROMs) and opioid consumption were not significantly different between both procedures at the 6-week follow-up. However, UKAs had significantly better range of motion and shorter operative time and length of stay8. A matched comparison between cementless UKA and TKA showed that, at 6 months postoperatively, UKAs had a significantly greater proportion of excellent Oxford Knee Scores and a lower proportion of poor scores9. Two RCTs compared robotic arm-assisted bi-UKA (1 UKA for the medial compartment and 1 UKA for the lateral compartment of the same knee) with conventional TKA. Banger et al.10 showed that the percentage of patients achieving normal sagittal gait patterns was not significantly different between both groups. Blyth et al.11 compared clinical outcomes and PROMs between robotic-arm-assisted bi-UKA and conventional TKA at 6 weeks and 1 year postoperatively and showed no significant differences at any point in time regardless of the outcome measure. For isolated patellofemoral osteoarthritis, an RCT comparing patellofemoral arthroplasty with TKA at 6 years postoperatively found no significant differences in revision rates12. However, the possibility of higher revision rates in the long term using patellofemoral arthroplasty warrants further investigation. Clinical Results and Outcomes At a minimum follow-up of 10 years, a large population database study demonstrated that UKA survivorship was >80%, and mechanical loosening was responsible for 83.4% of revisions. Failure risk factors were younger age, diabetes, male sex, and cementless fixation13. In a retrospective study of lateral UKA, survivorship rates in patients ≥60 years of age were 98% at 5 years and 96% at 10 years. The survivorship end point was conversion to TKA14. Another study evaluating patients who underwent UKA showed that patients who had undergone a surgical procedure recently had a significant reduction in complications compared with patients who had undergone a surgical procedure between 2005 and 2015. Outpatient UKA compared with inpatient UKA was associated with a lower risk of complications15. A recent award-winning investigation showed that UKAs (medial and lateral) performed with an intact anterior cruciate ligament (ACL) did not have significantly better PROMs than UKAs performed with a deficient ACL, and survivorship was not significantly different at 10 years16. Finally, a trial evaluating whether virtual reality improves the surgical competence of trainees when performing UKA (on a Sawbones model) compared with the manufacturer’s technique guide and surgical video showed no significant differences between both groups in surgical times or performance17. Primary TKA Perioperative Care An RCT evaluated patients who received 8 days of postoperative semirigid extension-locked knee bracing compared with those who did not, and found that patients who received the brace showed better knee range of motion, articular function according to the Knee Society Score (KSS), and acute postoperative pain, with reduced opioid consumption within the first month after a primary unilateral TKA18. A prospective study found that preoperative carbohydrate consumption did not improve immediate postoperative nausea and vomiting, and preoperative fluid consumption did not increase the risk of adverse outcomes19. Future studies with larger sample sizes are needed to understand the effectiveness of these strategies in improving outcomes. Bleeding Control and Thromboprophylaxis Tranexamic acid (TXA) is commonly used as either a single dose or multiple doses. In a recent study, Shah et al. suggested that TXA for 3 days after TKA is more effective than a single-day use to reduce blood loss without increasing complications20. In another report, Magill et al. found that the administration of 1 g of intravenous TXA perioperatively and 4 oral 1-g doses over 24 hours postoperatively significantly reduced blood loss by 40% beyond that achieved with no TXA21. Another study showed that sequential administration of oral TXA for up to 5 days after intravenous TXA did not decrease the hemoglobin drop after TKA22. Similar results with regard to the utility of single-dose intravenous TXA have been substantiated in simultaneous bilateral TKA to minimize excessive blood loss and reduce transfusions23. In the current economic landscape, administering multiple doses of TXA needs to show a substantial clinical benefit in order to consider such strategies, even using the oral route. Tourniquet usage has garnered much attention in efforts to reduce blood loss, yet conflicting evidence on its use exists and its utilization remains largely surgeon preference24,25. Zak et al.26 found that tourniquet use did not affect pain scores, opioid consumption, or length of stay. Similar findings were also reported by Smith et al.27, who concluded that there were no substantial benefits with the use of short tourniquet time (instead of long tourniquet time) in primary TKA with regard to opioid consumption, patient-reported pain, KSS, length of stay, and postoperative hemoglobin levels. Anesthesia and Pain Management A randomized study comparing liposomal bupivacaine and ropivacaine in adductor canal blocks, both in addition to an interspace between the popliteal artery and capsule of the posterior knee (iPACK) block using ropivacaine, showed that the liposomal bupivacaine group had significantly shorter length of stay, decreased inpatient opioid usage, and increased improvement in WOMAC scores after TKA28. However, another RCT showed no supporting evidence for the use of liposomal bupivacaine in adductor canal blocks for pain relief following TKA when compared with ropivacaine29. Overall, studies evaluating combinations of nerve blocks seem to support improved benefits with this practice30,31. A double-blinded RCT showed that intraosseous morphine combined with a standard antibiotic solution decreased postoperative pain and pain medication use in TKA32. Another study revealed that continuous nefopam administration for 24 hours after TKA produced considerable analgesic effects for the first 6 hours and a notable reduction in morphine use at 48 hours postoperatively33. Duloxetine may also improve analgesia after TKA34. Patients who received it needed fewer opioids to reach similar pain scores, reported higher satisfaction with pain management, and stated that pain was less likely to interfere with their activities of daily living compared with patients who received a placebo. Although there is much optimism regarding all of these methods, it is important to consider that great variability exists in baseline pain tolerance from one patient to another. Implant Design Cemented versus cementless designs in TKA have been debated for some time. Mohammad et al.35 showed that both designs had 10-year implant survival rates of >95%; however, cementless TKAs had slightly higher revision rates (absolute difference, 0.5%) and reoperation rates (absolute difference, 1.3%). Another topic that lacks consensus is the appropriate level of constraint in primary TKA. A prospective randomized study sought to uncover whether posterior-stabilized implants are superior to more congruent, cruciate-substituting, medial-stabilized implants and found that patients who received medial-stabilized prostheses reported better PROMs at 1 and 2 years36. The maximum flexion at 2 years was 132° in the medial-stabilized group and 124° in the posterior-stabilized group (p < 0.0001). Another study compared medial congruent and cruciate-retaining tibial designs using radiostereometric analysis and found that both designs had similar migratory patterns for femoral and tibial components at the 2-year follow-up37. The contribution of metal allergy or hypersensitivity reaction to residual symptoms and early failure in TKA remains controversial. A recent award-winning study that measured metal ions in the knee following TKA with standard cobalt-chromium components as well as with nickel-free oxidized zirconium femoral and titanium tibial components showed that notable levels of chromium and nickel ions were generated during TKA performed with standard instrumentation. Cutting blocks and saw blades were the major source of these metal ions. The authors concluded that the use of hypoallergenic implants does not mitigate metal debris generation, specifically nickel38. Surgical Technique Aseptic tibial loosening remains a major reason for TKA revision. In an award-winning cadaveric study, Martin et al. randomized, in a side-to-side fashion, cemented tibial components into 2 groups: (1) the component was held without motion after impaction and complete cement polymerization, and (2) the contralateral knee component was subjected to a gentle range of motion and stability assessment 7 minutes after mixing the cement. The mean pull-out strength was 4,473 N for the motion cohort and 5,462 N for the no-motion cohort (p = 0.001). Based on these findings, the authors currently allow polymerization of the tibial tray before cementing the femoral component to minimize implant motion39. Surgical-site complications also remain an important reason for reoperations. In an RCT comparing knotless barbed sutures with standard sutures in the knee, Sah revealed that wound drainage and time-to-closure values were significantly lower with barbed sutures40. In a separate prospective study comparing 2-octylcyanoacrylate topical adhesive with subcuticular suture for skin closure in the same patient, Choi et al. revealed faster suture times using the adhesive, with no differences in complications or cosmesis at 6 months postoperatively41. Tapasvi et al. compared the anterior-posterior axis line (APAL) with the transepicondylar axis line (TEAL) for setting femoral component rotation in posterior-stabilized TKAs performed with cemented components and the measured resection technique. The mean femoral external rotation relative to the posterior condylar axis line was 3.0° using APAL and 3.3° using TEAL (p = 0.46), with no significant differences in knee flexion or Oxford Knee Scores at a minimum follow-up of 2 years42. In a multicenter RCT, Hampton et al. compared radiographic and clinical outcomes of TKAs performed utilizing either patient-specific instrumentation or standard cutting block techniques and found no significant differences in alignment or outcome measures at 5 years postoperatively43. In a radiostereometric analysis, Broberg et al. found no significant differences with regard to implant migration when utilizing either gap-balancing or measured resection techniques in bicruciate-stabilized TKAs. Both techniques seemed to be similarly safe and effective with this particular implant design44. In posterior-stabilized TKAs, an RCT compared patellar crepitus rates between inlay and onlay patellar resurfacing techniques up to 2 years postoperatively. Patellar crepitus occurred significantly more frequently in the onlay group45. Finally, a trial comparing normal-curing bone cement with slow-curing cement showed that, at 10 years, PROMs were similar between both cement groups, with no component revisions46. Technology-Assisted TKA New technologies assisting in TKA are gaining popularity among surgeons. In a registry study of 34,908 procedures, Kirwan et al. compared 30 and 90-day mortality rates after bilateral-simultaneous TKA performed with conventional instrumentation or technology-assisted instrumentation. The authors hypothesized that the use of technology-assisted instrumentation avoiding intramedullary involvement would decrease mortality. The odds ratio for 30-day mortality for technology-assisted compared with conventional bilateral-simultaneous TKA after adjusting for age, sex, and procedure year was 0.26 (p = 0.02), a significant reduction in mortality47. In a single-blinded RCT comparing conventional TKA with electromagnetic computer-navigated TKA, Clark et al. found no significant differences in PROMs at the 5-year follow-up48. A separate report comparing freehand balancing with sensor-guided balancing at a minimum follow-up of 2 years showed no significant differences in knee range of motion, length of stay, opioid consumption, VAS pain scores, surgical complications, or PROMs. However, operative time was significantly longer in the sensor-guided group49. A multicenter RCT, also comparing sensor balancing with manual balancing, found no significant differences in PROMs between both cohorts at the 2-year follow-up despite improved quantitative soft-tissue balance in the sensor group50. Although the clinical benefit of sensor-guided balancing remains questionable, it is important to note that these studies did not standardize the type of alignment and other surgical variables that could affect PROMs. Clinical Results and Outcomes Many patients who undergo TKA are obese. Dowsey et al.51 sought to determine whether patients with a BMI of ≥35 kg/m2 and end-stage osteoarthritis achieved better outcomes by undergoing bariatric surgery before TKA and found that weight loss following bariatric surgery reduced the risk of complications. Furthermore, significantly fewer patients required TKA following weight loss. PROMs are commonly used, but, to support care, it is necessary to understand the magnitude of change that has clinical relevance. Soh et al.52 reported that minimal clinically important changes for the Knee injury Osteoarthritis Outcome Score (KOOS)-12 ranged from 17.5 to 21.8 points using the mean change method, from 15.6 to 21.9 points using the receiver operating characteristic method, and from 14.3 to 16.5 points using predictive modeling at the 6-month follow-up. Another study found that, although PROMs in patients who underwent TKA improved significantly and to a clinically important extent from preoperatively to the 4-month to the 1-year follow-up, improvements from the 1-year to a minimum of 2 years of follow-up were small and did not reach the minimum clinically important difference for nearly all of the patient-reported outcomes evaluated. The authors concluded that PROMs are as clinically reliable and meaningful at 1 year as they are at 2 years53. Most health-care centers limit same-day joint replacement to healthier patients and specific surgeons. Reddy et al.54 reported that same-day discharge did not increase the risk of emergency department visits, unplanned readmissions, or complications compared with an inpatient stay for patients with an American Society of Anesthesiologists classification of ≥3. Singh et al.55 showed that patients who underwent same-day discharge were less likely to visit the emergency department within 90 days postoperatively compared with patients with an inpatient stay. Controversy still exists with regard to the safety of simultaneous bilateral TKA compared with 2 TKAs staged months apart. The findings of Johnson et al.56 suggested that bilateral TKA staged at a 1-week interval is safe, allows faster total recovery time, and has a comparable complication rate as delayed staged TKA (a second TKA within 1 year). However, prospective randomized studies are needed to confirm such findings. Some surgeons selectively resurface the patella on a case-by-case basis of perceived risks compared with benefits. Limberg et al.57 found that the 20-year survivorship without any aseptic patellar complication of cemented all-polyethylene patellar components was 93% and the risk factors for any aseptic patellar complications were male sex, age of <65 years, BMI of ≥30 kg/m2, and a patellar component being implanted before 2000. Remote Care Management Digital and remote models are beginning to be used in recovery and rehabilitation after TKA. The findings from a multicenter RCT have suggested that postoperative outcomes, including rates of manipulation under anesthesia, range of motion, and PROMs, are not different when comparing patients who received a smartwatch paired with a mobile application plus self-directed physical therapy and patients who underwent traditional formal physical therapy following primary TKA58. Web-based platforms used to enhance patient education and communication are being explored to improve patient engagement and satisfaction and to potentially reduce cost. In a recent RCT, Visperas et al. found no significant differences in satisfaction and health-care utilization with the addition of a web-based, interactive, patient-and-provider software platform to the standard of care59. The authors concluded that this platform is useful to reinforce patient education and communication and should be utilized as an element of virtual care rather than supplementing in-office follow-up. Revision TKA Implant Design and Surgical Technique Fixation in revision TKA can be challenging. To enlarge the area of the osseous interface and decrease forces on weakened bone, components with stems are often used, and these can be fully cemented or press-fit. Mills et al.60, using radiostereometric analysis, compared the long-term stability of revision total knee replacements with either fully cemented or press-fitted stems (hybrid fixation). Their findings showed good long-term fixation with no difference in micromotion and PROMs (at the 10-year follow-up) between fully cemented and hybrid fixation of stems in patients with Anderson Orthopaedic Research Institute type-I or II bone defects. However, this study included only 20 patients, thus rendering results statistically underpowered. Furthermore, metaphyseal porous cones or sleeves can also be used to manage bone loss. Risk Factors and Complications Multiple factors affect the risk of revision or complications after TKA. A recent registry report with a mean follow-up of 2.8 years showed that obese patients had a significantly higher risk of all-cause revision and revision for infection than non-obese patients61. Another registry study showed that poor knee-specific and generic PROMs at 6 months were associated with early revision. Every unit increase (worsening) in postoperative knee pain was significantly associated with a 31% increase in the likelihood of revision62. A different investigation compared minimally stabilized implants (cruciate-retaining, anterior-stabilized, pivot-bearing designs) with posterior-stabilized implants in terms of revision risk after TKA. There was a significant increase in the risk of all-cause revision and revision for infection with the use of posterior-stabilized implants63. In a large database study, Shen et al. revealed that patients who underwent early aseptic revision TKA, within 90 days postoperatively, had an increased risk of re-revision within 2 years and a higher risk of periprosthetic joint infection (PJI). Among all causes of early aseptic revision, pain was associated with higher odds of re-revision64. In a separate report, postoperative pain was associated with an increased risk of manipulation under anesthesia65. Tourniquet use in revision TKA for aseptic causes remains a poorly explored research area. Singh et al. showed that patients who did not have a tourniquet inflated had a larger hemoglobin decrease and greater estimated blood loss and were more likely to require a subsequent reoperation compared with patients who did have a tourniquet inflated66. Infection Prevention is better than treatment. Bhattacharjee et al.67 showed that a corticosteroid injection within 4 weeks before primary TKA may be associated with an increased risk of infection. No significant differences in risk were observed in injection timeframes beyond 4 weeks. Parkinson et al.68 revealed that intraosseous antibiotic administration entailed a significantly lower risk of PJI when compared with intravenous antibiotics. Although further investigation is needed to validate this practice, the results are encouraging. An award-winning study of 3,855 consecutive primary THAs and TKAs showed that extended oral antibiotic prophylaxis for 7 days resulted in a significant reduction in infections among patients with poor host factors69. PJI diagnosis remains challenging. In a multicenter study of patients undergoing hip and knee revision, a pathogen was identified in 65.9% of culture-negative patients when using next-generation sequencing. The majority of infections were polymicrobial70. Another award-winning study evaluated concordance (matching organisms) between preoperative synovial fluid culture and intraoperative cultures during revision TKA, and the concordance was only 76.4%; therefore, intraoperative cultures are still needed71. Synovial cell count before reimplantation seems to predict the outcome of PJI. In a separate report, Ascione et al. suggested that patients with a white blood-cell count of ≥934 cells/μL and polymorphonuclear percentage of ≥52% should not undergo reimplantation but should undergo a repeat debridement72. On a separate note, plasma D-dimer is not associated with the fate of reimplantation in 2-stage exchange arthroplasty73. With regard to PJI treatment, a randomized trial found that low-dose (500-mg) intraosseous regional administration of vancomycin achieved local tissue concentrations 5 to 15 times higher than the ones obtained by intravenous administration, despite the limited duration of tourniquet inflation (10 minutes after intraosseous regional administration)74. In a separate report, the intermediate-term (6-year) survivorship free from revision (because of PJI) of rotating-hinge knee prostheses for PJI by means of 1-stage exchange arthroplasty was 90%. Unfortunately, the all-cause revision rate was 25%75. PJI as a cause for revision in TKA was associated with an increased risk of venous thromboembolism. The odds of venous thromboembolism after revision for infection were twice those for aseptic revision, but fracture as an indication for revision was still associated with the highest risk76. Finally, a contemporary trial revealed that the placement of an antibiotic-impregnated cement spacer was an independent risk factor for acute kidney injury77. Special Considerations TKA in patients with high BMI takes longer, and these patients may be at greater risk for complications. Quayle et al.78 suggested that, although the issue of managing patients with high BMI is multifactorial, ensuring appropriate operating room scheduling and referring these patients with high BMI to specialist centers may be most beneficial. On a different topic, persistent sleep disturbance may negatively affect patients’ quality of life, pain, and postoperative recovery. Daily use of exogenous melatonin for 6 weeks did not demonstrate any noteworthy effect in mitigating decreases in sleep quality79. Lastly, an investigation found that cannabis use disorder in patients undergoing TKA is associated with longer hospital length of stay and higher rates of complications and care costs80. Evidence-Based Orthopaedics The editorial staff of JBJS reviewed a large number of recently published studies related to the musculoskeletal system that received a higher Level of Evidence grade. In addition to articles cited already in this update, 9 other articles relevant to adult reconstructive knee surgery are appended to this review after the standard bibliography, with a brief commentary about each article to help guide further evidence-based reading in this subspecialty area. Evidence-Based Medicine Haffar A, Khan IA, Abdelaal MS, Banerjee S, Sharkey PF, Lonner JH. Topical cannabidiol (CBD) after total knee arthroplasty does not decrease pain or opioid use: a prospective randomized double-blinded placebo-controlled trial. J Arthroplasty. 2022 Sep;37(9):1763-70. This randomized, double-blinded, placebo-controlled trial of 80 patients sought to analyze the analgesic benefits of topical cannabidiol (CBD) following primary TKA. Of the 80 patients included, 19 applied topical CBD, 21 applied essential oil, 21 applied CBD and essential oil, and 19 applied a placebo 3 times a day for 2 weeks postoperatively. The findings suggested that the local effects of topical CBD do not provide additional pain relief after TKA because the utilization of topical CBD in supplement to multimodal analgesia did not reduce pain or opioid consumption or improve sleep scores when compared with placebo, essential oils, or a combination of CBD and essential oils. The results of this study are difficult to interpret because of the lack of adequate statistical power. It is also unclear how limb size, musculature, and subcutaneous adipose volume may impact the absorption of CBD and its distribution to the relevant tissues. Lastly, only 1 concentration of topical CBD was analyzed in this study. Future research should account for varying concentrations of topical CBD to assess optimal efficacy. Hamilton WG, Gargiulo JM, Reynolds TR, Parks NL. Prospective randomized study using pharmacogenetics to customize postoperative pain medication following hip and knee arthroplasty. J Arthroplasty. 2022 Jun;37(6S):S76-81. In this study, pharmacogenetic testing was performed for genetic variants on a panel of 16 genes, including CYP2D6, CYP2C9, OPRM1, and CYP1A2, using buccal swabs collected preoperatively from 107 patients. Patients were randomized to a control group or a custom group and were blinded to their group. The authors found that custom postoperative pain prescriptions based on pharmacogenetic testing allowed patients to achieve lower pain levels while reducing the consumption of pain medication. The results of this study raise awareness of the existence of a genetic predisposition to metabolize pain medications in a different manner. Therefore, surgeons should recognize that it is not unreasonable for patients to report different responses to pain medications. Alterations to customize pain protocols could have compelling effects if applied to a larger cohort. Thus, a more robust study is warranted. Huang CR, Pan S, Li Z, Ruan RX, Jin WY, Zhang XC, Pang Y, Guo KJ, Zheng X. Tourniquet use in primary total knee arthroplasty is associated with a hypercoagulable status: a prospective thromboelastography trial. Int Orthop. 2021 Dec;45(12):3091-100. Of the 154 patients included in this analysis, 79 patients were randomized into a tourniquet group and 75 patients were randomized into a no-tourniquet group. The investigators found that the tourniquet group had higher levels of fibrin degradation products and D-dimer in conventional coagulation tests as well as higher maximum amplitude and coagulation index in thromboelastography analyses. Additionally, the incidence of deep vein thrombosis in the tourniquet group was shown to be higher than that in the no-tourniquet group. The authors concluded that tourniquet use in routine TKA results in exacerbation of the early postoperative hypercoagulable status coupled with a higher incidence of below-the-knee asymptomatic deep vein thrombosis. Despite the decreased intraoperative blood loss with the utilization of tourniquets, the calculated total blood loss increased in this study. These findings should be interpreted in light of the limited sample size (n = 154); thus, a larger study is warranted to further validate the results. Jensen CB, Troelsen A, Petersen PB, JØrgensen CC, Kehlet H, Gromov K. Centre for Fast-Track Hip and Knee Replacement Collaborative Group. Influence of body mass index and age on day-of-surgery discharge, prolonged admission, and 90-day readmission after fast-track unicompartmental knee arthroplasty. Acta Orthop. 2021 Dec;92(6):722-7. This retrospective analysis included 3,897 patients who underwent UKA in 8 fast-track arthroplasty centers to investigate the effect of BMI and age on same-day discharge, prolonged admission, and 90-day readmission. Patients were divided into 5 BMI groups and 5 age groups. Same-day discharge was achieved in 26% of patients, with no significant differences between BMI groups, but it was less likely in patients who underwent UKA and were 71 to 80 years of age, and 90-day readmission was more likely in patients with a BMI of >35 kg/m2 and patients who were 71 to 80 years of age. We consider that these findings can be used as part of the shared decision-making process between surgeon and patient. Kampitak W, Tanavalee A, Ngarmukos S, Cholwattanakul C, Lertteerawattana L, Dowkrajang S. Effect of ultrasound-guided selective sensory nerve blockade of the knee on pain management compared with periarticular injection for patients undergoing total knee arthroplasty: a prospective randomized controlled trial. Knee. 2021 Dec;33:1-10. A comparison of the postoperative analgesic effect of selective sensory nerve blockade (SSNB) or periarticular infiltration (PAI) in combination with a multimodal analgesic regimen including continuous adductor canal block in 72 patients undergoing TKA was conducted. Patients were randomly assigned to either the SSNB group or the intraoperative PAI group. The results suggest that, despite not providing superior postoperative analgesia or improvement in immediate functional performance, SSNB may lower opioid consumption in the first 48-hour postoperative period compared with intraoperative PAI. These findings may have been affected by the use of a continuous adductor canal block, which may have caused the observed overall low pain score in the immediate postoperative period in both groups. Layson JT, Markel DC, Hughes RE, Chubb HD, Frisch NB. John N. Insall Award: MARCQI’s Pain-Control Optimization Pathway (POP): Impact of registry data and education on opioid utilization. J Arthroplasty. 2022 Jun;37(6S):S19-26. The authors of this study aimed to determine if education could influence and have lasting effects on the prescribing patterns for patients who undergo total joint arthroplasty (TJA), using the Michigan Arthroplasty Registry Collaborative Quality Initiative (MARCQI) database. The data included 84,998 TJAs: 22,774 total hip arthroplasties (THAs) in opioid-naive patients, 9,124 THAs in opioid-tolerant patients, 40,882 TKAs in opioid-naive patients, and 12,218 TKAs in opioid-tolerant patients. It was found that the MARCQI pain control optimization pathway program was successful in reducing opioid prescribing, with lasting effects, and substantially limited the overall opioid prescription burden for patients undergoing joint replacement. Although the findings of this study are promising, there are inherent limitations to registry data that prevent definitive conclusions from being made. Additionally, this study did not address short-term or long-term clinical outcomes as they relate to changes in opioid prescribing. Lindsey MH, Mortensen S, Xu H, McNichol M, Abdeen A. The role of acupuncture in postoperative pain management of patients undergoing knee arthroplasty surgery: a systematic review and meta-analysis. JBJS Rev. 2021 Aug 20;9(8). This was a systematic review and meta-analysis that examined the effect of acupuncture on postoperative pain, opioid consumption, and nausea and vomiting after TKA. The authors concluded that acupuncture after TKA may decrease the incidence of postoperative nausea and vomiting; however, it did not decrease VAS pain scores in the 0 to 48-hour interval but did decrease VAS scores at >48 hours after TKA. The particular type of acupuncture may have an impact, as there was a reduced analgesic consumption with auricular acupuncture and traditional acupuncture when compared with electroacupuncture. The heterogeneity of the included studies prevented the meta-analysis of opioid use with acupuncture after TKA, but the systematic review demonstrated mixed results. One major limitation of this review was the lack of studies on the subject. Larger, high-quality RCTs are required to further validate these findings. McDonald C, Feeley I, Flynn S, Farrell A, Kelly M, Sheehan E. The addition of oral tranexamic acid to knee arthroplasty patients does not further improve blood loss: a double blinded randomized control trial. Acta Orthop Belg. 2022 Jun;88(2):335-41. This study sought to identify the efficacy and safety of combined perioperative intravenous and postoperative oral TXA on blood loss and hemoglobin drop compared with the administration of perioperative intravenous TXA alone in 50 randomized patients undergoing primary TKA. The first group received perioperative intravenous TXA and postoperative oral TXA (n = 26), and the second group received perioperative intravenous TXA plus 48 hours of additional oral placebo (n = 24). The authors found no significant difference between the 2 groups with regard to total blood loss and hemoglobin drop, concluding that the administration of oral TXA did not further improve blood loss compared with administration of perioperative intravenous TXA preoperatively as well as at wound closure. It is important to highlight that, although the authors reported a trend in decreased total blood loss, a larger patient cohort may be required to elucidate significant findings. Sepucha KR, Vo H, Chang Y, Dorrwachter JM, Dwyer M, Freiberg AA, Talmo CT, Bedair H. Shared decision-making is associated with better outcomes in patients with knee but not hip osteoarthritis: the DECIDE-OA randomized study. J Bone Joint Surg Am. 2022 Jan 5;104(1):62-9. This multicenter, randomized study examined whether patients who made high-quality, informed, patient-centered decisions had better health outcomes, higher satisfaction, and less decision regret compared with patients who made lower-quality decisions. The investigators utilized 2 decision aids for patients with hip and knee osteoarthritis at 2 time points: shortly after the initial surgical evaluation and about 6 months after treatment. They found that higher-quality decisions predicted small gains in health outcomes, greater satisfaction, and less regret for patients with knee osteoarthritis. Interestingly, this was not true for patients with hip osteoarthritis. We consider that the results of this study provide an impetus for future research to assess whether the relationship between informed, patient-centered decisions and health outcomes will vary over time and whether the results are generalizable to more diverse populations.