What’s New in Adult Reconstructive Knee Surgery

In the current Guest Editorial, we evaluate and summarize the most relevant findings from recent, meaningful, peer-reviewed publications in different research areas. Articles at various Levels of Evidence were included, but increased attention was paid to Level-I and award-winning reports. Economics Considerable debate continues with regard to the economics of reconstructive knee surgery. An updated Medicare projection revealed that, by 2040, the annual number of revision total knee arthroplasties (TKAs) performed would be 115,147, whereas, by 2060, it would be 286,740. These values are important for understanding the future health-care resource utilization involving revision TKA, which is only expected to increase1. A secondary analysis of a randomized clinical trial (RCT) evaluating health-care resource utilization up to 12 months after primary TKA, among dissatisfied and satisfied patients, showed that patients dissatisfied with their return to function incurred a mean cost of $19,007.70, compared with $13,523.83 for satisfied patients (p = 0.07). Although the cost difference was not significant, its magnitude deserves attention2. Data from the New Zealand Joint Registry indicated that patients undergoing TKA have a mortality rate 8% higher than that of the general population3. Assessing mortality after primary TKA is relevant for future economic analyses. Osteoarthritis of the Knee Various nonoperative treatments for knee osteoarthritis were evaluated in the last year. An RCT comparing the efficacy of a single intra-articular injection of platelet-rich plasma combined with 2 different hyaluronans (platelet-rich plasma and hyaluronan #1 compared with platelet-rich plasma and hyaluronan #2) for the treatment of Kellgren-Lawrence grade-2 knee osteoarthritis showed significant improvements in pain reduction (change in visual analog scale [VAS] pain score from baseline to 6 months after the injections) for both groups4, whereas a systematic review and meta-analysis evaluating the efficacy of intra-articular platelet-rich plasma combined with mesenchymal stem cells also revealed that such a combination significantly reduces knee pain5. However, none of these studies included a placebo control group. A noninferiority RCT evaluating the efficacy of intra-articular triamcinolone acetonide (10 compared with 40 mg) for knee osteoarthritis revealed that both groups achieved significant pain reduction from baseline to 12 weeks after the injection, but there were no significant differences between the 2 groups6. In a systematic review and meta-analysis of RCTs, Pereira et al.7 found that viscosupplementation was associated with a reduction in pain intensity when compared with placebo. However, the observed difference was less than the minimal clinically important difference (MCID). Viscosupplementation was associated with an increased risk of serious adverse events compared with placebo. The placebo effect should not be overlooked in investigations involving knee injections for osteoarthritis treatment, and safety should also be evaluated. Finally, an RCT assigning patients with knee osteoarthritis and overweight or obesity to either a diet and exercise intervention or an attention control group (social interaction, evidence-based health, and nutrition education) for 18 months showed that diet and exercise led to a significant decrease in knee pain, although it was of uncertain clinical relevance due to the small magnitude of the pain reduction8. Unicompartmental Knee Arthroplasty (UKA) UKA Compared with TKA The debate between UKA and TKA for unicompartmental knee osteoarthritis treatment is not over. An RCT comparing the 2-minute walk test (2MWT) and the Timed Up-and-Go (TUG) test results between UKA and TKA performed for isolated medial knee osteoarthritis showed that the mean 2MWT distance after UKA was significantly longer than that after TKA at 6 weeks and 3 and 6 months postoperatively. The TUG test time after UKA was also significantly shorter at 6 weeks and 3 months postoperatively. However, the performance-based tests results at 1 and 2 years were similar9. When compared with TKA, morbidly obese patients (body mass index [BMI] ≥40 kg/m2) undergoing UKA had significantly fewer 90-day complications, readmissions, and periprosthetic joint infections (PJIs), in addition to shorter length of stay and lower health-care utilization in the short term. Nevertheless, patients undergoing UKA exhibited higher odds of mechanical loosening10. In a prospective, matched-cohort study comparing patient-reported outcome measures and satisfaction between medial UKA and TKA, patients who underwent UKA were significantly more likely to consider the knee as a forgotten joint (according to the Forgotten Joint Score [FJS]) and exhibited improved satisfaction11. In a matched comparison study applying the FJS and the Knee Society score, Brilliant et al.12 found that, at 5 years postoperatively, patients who had undergone medial UKA had less joint awareness and higher function than patients who had undergone TKA. Implant survivorship was not significantly different. UKA remains a valuable option to treat medial knee osteoarthritis. Clinical Results and Outcomes The indications and implant types for UKA remain under investigation. In a retrospective study, the impact of mechanical alignment and alignment correction on patient-reported outcome measures after robotic medial UKA was evaluated at a mean follow-up of 2.4 years. Although not significant, patients who had >8° postoperative varus experienced a 20% lower MCID achievement rate for the Knee Injury and Osteoarthritis Outcome Score for Joint Replacement compared with patients who had ≤8° of varus13. At a mean follow-up of 5 years, a retrospective study of 2,305 patients assessed the impact of proximal tibial varus alignment on implant survivorship after medial UKA. The all-cause revision rate was not significantly different (p = 0.492) between patients with preoperative medial proximal tibial angles of <80° (5.8%) and ≥80° (4.9%)14. Data from 366 patients who underwent robotic medial UKA were analyzed in a prospective, multicenter study to determine the 10-year implant survivorship and satisfaction among patients without revision. Survivorship was 91.7%, and the proportion of patients who were either very satisfied or satisfied with the operatively treated knee was 91%15. In a long-term population-based cohort study of 2,015 patients, cemented fixed-bearing UKAs or mobile-bearing UKAs performed without cement exhibited better implant survivorship compared with cemented mobile-bearing designs at a mean follow-up of 8 years16. In a Norwegian Arthroplasty Register report (7,549 Oxford UKAs), investigators found a higher risk of revision for periprosthetic fracture (hazard ratio [HR], 15; p < 0.001) and for infection within 1 year (HR, 3.0; p = 0.001) with use of the uncemented Oxford Partial twin-peg femoral component design compared with the cemented Oxford Partial design. The cemented implant used in the new Oxford Partial UKA appears to be a better option than its uncemented counterpart17. Primary TKA Perioperative Care Extensive debate continues with regard to tourniquets. An award-winning RCT evaluated tourniquet effects on early recovery after TKA, utilizing a smartphone application with a wrist-based activity monitor, and revealed that tourniquet use did not have a detrimental effect on pain, opioid consumption, function, or physical therapy performance within 90 days after the surgical procedure18. Another RCT showed no differences with regard to blood loss, thigh and knee pain, edema, and complications between patients who underwent the procedure without a tourniquet and those patients who had optimized use of it19. With regard to quadriceps muscle strength and volume recovery after TKA, a trial comparing perioperative essential amino acid supplementation with placebo showed that the supplementation significantly improved the rectus femoris muscle area and quadriceps muscle strength at 2 years after TKA, although clinical outcomes such as knee pain, 6-meter walk, daily living activities, and range of motion were not significantly different20. A separate RCT comparing vitamin D3 supplementation before TKA with placebo did not demonstrate significant improvements in function, the TUG test, or complications up to 6 weeks after the surgical procedure21. The role of cryotherapy after TKA was evaluated in a systematic review of RCTs, which showed a significant decrease in opioid consumption during the first postoperative week in cryotherapy groups; however, swelling and knee range of motion did not appear to improve with this treatment modality22. In an award-winning study, Shaw et al. evaluated the use of oral dexamethasone compared with placebo capsules up to 4 days after TKA and found a significant decrease in postoperative VAS pain when using oral dexamethasone but no significant differences with regard to opioid use, nausea, vomiting, 90-day complications, ability to walk with or without assistance, or early patient-reported outcome measures23. Bleeding Control and Thromboprophylaxis A trial evaluating blood loss and thromboprophylaxis after TKA randomized patients to either an intermittent pneumatic compression device or enoxaparin. No patient had a symptomatic venous thromboembolism. Nevertheless, patients using an intermittent pneumatic compression device had a significantly smaller increase in postoperative leg and ankle circumference (edema) and reduced blood loss24. The effect of aspirin compared with enoxaparin on symptomatic venous thromboembolism within 90 days after TKA and total hip arthroplasty was evaluated in the CRISTAL trial, which revealed a lower symptomatic venous thromboembolism rate in the enoxaparin group. However, most differences with regard to venous thromboembolism events represented differences in below-the-knee deep venous thrombosis rates, which are not as clinically important as above-the-knee deep venous thrombosis or pulmonary embolism25. Anesthesia and Pain Management The effectiveness and safety of multiple anesthesia modalities were the subject of new reports. A systematic review and direct meta-analysis showed that femoral nerve and adductor canal blocks reduced postoperative pain and opioid consumption, although femoral nerve blocks were associated with quadriceps weakness. No significant difference with regard to pain and opioid consumption was observed between adductor canal blocks and local peri-articular anesthetic infiltration26. By the same token, an RCT found no benefit of adductor canal blocks compared with anterior peri-articular anesthetic infiltration with regard to cumulative morphine consumption at 48 hours after primary TKA; of note, both groups received posterior peri-articular anesthetic infiltration with a local anesthetic27. Chatmaitri et al.28 found that the addition of an infiltration between the popliteal artery and capsule of the knee (iPACK block) in patients already receiving adductor canal blocks and peri-articular anesthetic infiltration does not appear to reduce pain or opioid consumption after TKA. Likewise, over the first 48 hours postoperatively, continuous catheter-based adductor canal blocks did not appear to improve resting pain severity or cumulative opioid consumption when compared with single-shot adductor canal blocks according to Hussain et al.29. A separate trial comparing liposomal bupivacaine with ropivacaine in adductor canal blocks before primary TKA showed that patients receiving liposomal bupivacaine had lower pain levels, shorter hospital lengths of stay, and lower inpatient opioid consumption. Both groups received an iPACK block using ropivacaine30. In a separate study of patients receiving ultrasonic-guided adductor canal and iPACK blocks, combined dexamethasone and ropivacaine yielded a significantly longer time to the first administration of rescue analgesic drugs compared with ropivacaine alone31. In another investigation, 100 patients were randomized to receive a peri-articular anesthetic infiltration with either a conventional cocktail containing ropivacaine, epinephrine, and dexamethasone or a modified cocktail that comprised the same mixture plus 2.5 mg/mL of magnesium sulfate and 15 mg/mL of sodium bicarbonate. The use of the modified cocktail significantly decreased morphine consumption (4.2 compared with 14.6 mg; p < 0.001) in the first 24 hours after the surgical procedure and the overall total morphine use (9.8 compared with 19.6 mg; p < 0.001)32. The efficacy of opioids in preemptive multimodal analgesia for pain control after TKA was evaluated in a double-blinded study that randomized 100 patients to receive 400-mg celecoxib, 150-mg pregabalin, and 10-mg extended-release oxycodone hydrochloride, or 400-mg celecoxib, 150-mg pregabalin, and placebo. The addition of oxycodone did not result in significant differences with regard to postoperative morphine consumption as rescue analgesia, time to the first rescue analgesia, VAS pain, knee range of motion, ambulation distance, complication rates, or time until hospital discharge33. Finally, the addition of topical cannabidiol after TKA as a supplement to multimodal analgesia did not appear to provide additional benefits in terms of pain, sleep scores, or opioid consumption34. Implant Design The search for better TKA designs endures. An RCT comparing 3 commonly used patellar implant designs (inlay, onlay round, and onlay oval) found no significant differences in terms of Kujala score changes from preoperatively to 2 years postoperatively or implant survivorship35. Allergies to implant materials may well be responsible for unexplained poor results after TKA. In an RCT, a novel multilayer hypoallergenic coating for implants used in TKA was compared with the implants used in standard TKA (both implants consisted of a cobalt, chromium, and molybdenum alloy). However, there were no differences with regard to cumulative 10-year implant survivorship (98% for both) or a relevant increase in metal-ion serum levels36. A Level-I study compared 99 patients who underwent a posterior-stabilized TKA with 101 patients who received a cruciate-substituting, medial-stabilized device implanted with kinematic alignment. At 2 years postoperatively, the Knee Society pain/motion score was 88 in the posterior-stabilized group and 96.16 in the medial-stabilized group (p < 0.0001), whereas the mean FJS was 58.3 in the posterior-stabilized group and 68.29 in the medial-stabilized group (p = 0.017). No significant differences were observed in Knee Society function scores or revision rates37. In a separate report also comparing posterior-stabilized and medial-stabilized implants, the medial-stabilized group exhibited significantly less total anterior-posterior displacement (mean, 3.6 compared with 16.5 mm; p < 0.0001). All patients in the medial-stabilized group returned to sports activities according to the FJS38. A trial compared mobile-bearing and fixed-bearing TKA designs and showed that there were no significant differences with regard to the FJS, overall crepitus rates, range of motion, Knee Society score, Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), or radiographic outcomes39. The James A. Rand Young Investigator’s Award winner, an American Joint Replacement Registry (AJRR) analysis, also compared mobile-bearing and fixed-bearing designs and revealed that mobile-bearing TKAs had an increased risk of all-cause revision (HR, 1.36; p < 0.0001)40. A separate analysis of AJRR data revealed that, when compared with minimally stabilized implants (cruciate-retaining, anterior-stabilized, and pivot-bearing designs), posterior-stabilized implants had a significantly higher risk of all-cause revision (HR, 1.25; p < 0.0001) and revision for infection (HR, 1.18; p = 0.02)41. A bicruciate-retaining TKA design exhibits a different kinematic pattern in early flexion and late extension compared with a posterior cruciate-retaining TKA design, according to a recent report42. Significantly higher tibial migration was observed in the bicruciate-retaining group; as a result, longer follow-up of the newer bicruciate-retaining TKA design is warranted. An award-winning RCT demonstrated that hybrid (cemented baseplate with uncemented pegs) monoblock and cementless monoblock tibial designs have excellent implant survivorship (96%) at a mean follow-up of 10 years. However, the traditional modular cemented tibial design group showed significantly more revisions (p = 0.003) for aseptic tibial loosening (7%) than the hybrid or cementless tibia groups (0% for the other 2 groups)43. Surgical Technique The effectiveness of various surgical techniques in TKA were the focus of multiple investigations. In an RCT of patients who did not undergo patellar resurfacing, patellar rim denervation using electrocautery did not appear to provide clinically relevant benefits with regard to anterior knee pain compared with no denervation44. With regard to patellar resurfacing, a systematic review and meta-analysis of RCTs revealed that resurfacing reduced anterior knee pain and revision risk compared with no resurfacing45. A prospective study showed that 75% of patients reported thigh pain on postoperative day 1 regardless of tourniquet or intramedullary guide use during the surgical procedure, but, at 2 weeks postoperatively, tourniquet use appeared to increase the odds of a quadriceps strain46. Another RCT demonstrated that the placement or length of the surgical incision did not significantly affect the rate of postoperative numbness. At the 1-year follow-up, most patients had recovered any loss of sensation47. Technology-Assisted TKA Compared with standard freehand balancing, the use of a sensor-guided balancing device did not appear to provide additional benefits with regard to VAS pain scores, length of stay, range of motion, or patient-reported outcome measures, but its use was associated with longer operative time48. Only femoral coronal alignment was significantly different (p = 0.003) in a study comparing handheld accelerometer-based navigation (89.4°) with conventional instruments (87.7°)49. The inflammatory response of patients treated with robotic-arm-assisted TKA compared with those treated with TKA using conventional instruments was evaluated in an RCT that showed significantly lower levels of interleukin 6 and 8 (from intra-articular drain fluid at 6 hours postoperatively) in the robotic TKA group. VAS pain scores were also significantly lower in this group on postoperative days 1, 2, and 750. A systematic review and cross-sectional study of RCTs compared the long-term survivorship of computer-navigated TKA and TKA with conventional instruments using the concept of the reverse fragility index (RFI), which quantifies the strength of a study’s neutral results by calculating the minimum number of events required to flip results from nonsignificant to significant. Investigators found that, at the p < 0.05 threshold, a median of just 4 events would be needed to flip results. They proposed that the RFI should be routinely used in trials with nonsignificant results51. Outcomes The American Association of Hip and Knee Surgeons Clinical Research Award winner, a retrospective study of 1,093 primary TKAs and patient-reported outcome measures related to pain, function, activity level, and satisfaction, showed that improvements from 1 year to a minimum follow-up of 2 years were minimal and did not reach the MCID for most outcomes evaluated, calling into question the 2-year minimum follow-up usually required in peer-reviewed journals52. There are considerable inconsistencies among the MCIDs reported for patient-reported outcome measures in TKA, according to a recent systematic review of articles that calculated MCID values53. However, despite inconsistencies, the number of articles reporting MCIDs for patient-reported outcome measures appears to have improved over the last decade54. In any case, MCIDs should be reported whenever patient-reported outcome measures are evaluated. Revision TKA Implant Design The debate persists over the use of fully cemented stems compared with press-fit fixation stems. In an RCT of 32 patients, including 19 with long-term follow-up utilizing radiostereometric analysis of femoral and tibial components, Mills et al.55 showed that there were no significant differences in long-term micromotion between fully cemented and press-fit fixation stems. Both types of fixation yielded similar long-term stability. Infection The winners of the Mark Coventry Award, Fernández-Rodríguez et al.56, observed that the human knee has a distinct microbiome. After evaluating synovial fluid from normal knees, osteoarthritic knees, and knees that underwent septic or aseptic revisions, researchers found that native osteoarthritic knees had the highest number of species. Cutibacterium species (28.0%), Staphylococcus species (14.9%), and Paracoccus species (29.5%) prevailed in native non-osteoarthritic knees. The role of these interesting findings with regard to osteoarthritis and PJI etiologies deserves further investigation. Goh et al.57 assessed whether serum glucose variability increases the risk of complications after aseptic revision TKA, making use of the coefficient of variation. This coefficient was divided into 3 tertiles: low, moderate glycemic variability, and high glycemic variability. Unexpectedly, the investigators found that the associations (regressions) between the coefficient-of-variation tertiles and complication, PJI, mortality, and non-home discharge variables were not significant in revision TKA, although they argued that the relatively small sample size (n = 636) was responsible for these findings. Factors associated with the development of subsequent PJI among patients with ipsilateral hip and knee arthroplasties who initially experienced infection of 1 of the implants were addressed by Akkaya et al.58. Patients who developed ipsilateral metachronous PJI had significantly shorter stem-to-stem (tip-to-tip) distances (8 compared with 14 cm; p < 0.01) and empty (no foreign body such as cement) native bone distances (5 compared with 11 cm; p < 0.01), as well as an elevated risk of cement extrusion beyond its restrictor (70% compared with 5%; p < 0.01) compared with patients who did not develop infection. Abuzaiter et al.59 conducted a noninferiority RCT to determine whether topical vancomycin powder is a valuable option for preventing infections after TKA. When compared with a standard postoperative antibiotics group (n = 85), patients who received 1 g of vancomycin powder intraoperatively and no postoperative antibiotics (n = 80) exhibited a greater rate of postoperative PJI (3.75% compared with 0%; p = 0.03). Patients in both groups received standard preoperative intravenous antibiotics (cefazolin or vancomycin) before incision. With regard to a PJI diagnosis, Tarabichi et al.60 conducted a prospective study involving 502 patients undergoing revision hip or knee arthroplasty and assessed the diagnostic accuracy for PJI of plasma D-dimer, the serum erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and fibrinogen. In a knee subgroup analysis, the area under the curve (AUC) for the 4 biomarkers was 0.904 for plasma D-dimer, 0.856 for serum ESR, 0.891 for CRP, and 0.815 for fibrinogen. Plasma D-dimer exhibited the lowest positive predictive value (0.567) but had the highest negative predictive value (0.965). A negative D-dimer test result appears to be valuable to rule out infection. Machine Learning and Artificial Intelligence Machine learning and artificial intelligence technologies are gradually finding their way into diverse areas. A systematic review with regard to clinical applications of machine learning to PJI prevention revealed its value with respect to preoperative health optimization, surgical planning, early infection diagnosis, early antibiotic use, and prediction of clinical outcomes61. Mehta et al.62 compared 14 pathologist-scored histology features and computer vision-quantified cell density (147 patients with osteoarthritis and 60 patients with rheumatoid arthritis) in hematoxylin and eosin-stained images of synovial tissue samples from TKA explants. A trained random-forest model correctly classified those images as showing osteoarthritis or rheumatoid arthritis in 82% of samples. With regard to primary TKA, Chen et al.63 established the utility of machine learning for predicting non-home discharge after a surgical procedure, and machine learning models showed excellent predictive capabilities during internal and external validations. A machine learning algorithm was able to predict the worsening of the flexion range of motion after primary TKA. The random-forest model had the best accuracy, and variables of importance were joint-line change, postoperative femorotibial angle, and hemoglobin A1c64. Yeramosu et al.65 compared a multivariable logistic regression model and diverse machine learning techniques and found that 1 of the models (random forest) had an accuracy (AUC) of 0.810 for identifying candidates for same-day discharge after revision TKA. According to that model, the factors of importance for same-day discharge, in decreasing order, were operative time, anesthesia type, age, BMI, American Society of Anesthesiologists (ASA) class, race, diabetes, revision TKA type, sex, and smoking. With regard to discharge disposition following revision TKA, Buddhiraju et al.66 validated the non-home discharge prediction capabilities of machine learning models using various databases. Age, BMI, and surgical indication were the strongest predictors of non-home discharge. Jang et al.67 developed a deep learning algorithm to automatically delineate revision TKA zones and cone placements on anteroposterior radiographs in a standardized manner. The algorithm was validated by comparison with a trained surgeon, and it was able to define zones in 98% of images using anatomical landmarks. For the femur, cone identification accuracy was 98% and zonal cone placement accuracy was 96%, and, for the tibia, cone identification accuracy was 96% and zonal cone placement accuracy was 89%. Klemt et al.68 evaluated 3 learning algorithms to predict PJI after aseptic revision TKA. Their artificial neural network model outperformed others. The strongest predictors were a prior open procedure before revision TKA, drug abuse, obesity, and diabetes. 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 the 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 your further reading, in an evidence-based fashion, in this subspecialty area. Evidence-Based Orthopaedics Cooper HJ, Bongards C, Silverman RP. Cost-effectiveness of closed incision negative pressure therapy for surgical site management after revision total knee arthroplasty: secondary analysis of a randomized clinical trial. J Arthroplasty. 2022 Aug;37(8S):S790-5. In this RCT, the authors employed a health economic model and gauged expenses tied to 90-day surgical site complications after revision TKA to perform a cost-benefit analysis of closed-incision negative pressure therapy compared with the standard of care. The results showed that patients treated with closed-incision negative pressure therapy experienced fewer surgical site complications, requiring fewer operative and nonoperative interventions, compared with patients treated with the standard of care. Despite higher upfront dressing costs, closed-incision negative pressure therapy proved cost-effective, reducing postoperative surgical site management expenses by 49% overall, and by 79% in higher-risk patients. This valuable report shows that closed-incision negative-pressure therapy potentially benefits both patients and health-care systems by helping to reduce the economic burden associated with revision TKA. Cox ZC, Engstrom SM, Shinar AA, Polkowski GG, Mason JB, Martin JR. Is cement mantle thickness a primary cause of aseptic tibial loosening following primary total knee arthroplasty? Knee. 2023 Jan;40:305-12. This retrospective study evaluated the role of cement mantle thickness in aseptic tibial loosening after primary TKA. The investigators analyzed data from 216 patients who underwent revision TKA due to aseptic tibial loosening and assessed cement mantle thickness on preoperative radiographs and the interface that failed (implant-cement or cement-bone). Most patients (203 of 216) experienced radiographic failure at the implant-cement interface. Those patients who had a failed cement-bone interface had a significantly thinner cement mantle compared with patients who had a failed implant-cement interface. These findings suggest that strategies to prevent tibial implant loosening should focus on enhancing fixation at the implant-cement interface. This is an important study that sheds light on the mechanisms contributing to implant loosening and emphasizes the need for always optimizing cementing techniques. Dossett HG, Arthur JR, Makovicka JL, Mara KC, Bingham JS, Clarke HD, Spangehl MJ. A randomized controlled trial of kinematically and mechanically aligned total knee arthroplasties: long-term follow-up. J Arthroplasty. 2023 Jun;38(6S):S209-14. This RCT investigated the long-term outcomes of kinematically and mechanically aligned TKAs. A total of 62 surviving patients who had undergone these procedures approximately 13 years earlier were followed. One group underwent a kinematically aligned TKA using patient-specific guides and the other group underwent a mechanically aligned TKA using conventional instruments. The investigators found that both alignment methods had comparable results in terms of reoperations, complications, and patient-reported outcome measures. The kinematically aligned group reported slightly higher satisfaction rates (96% compared with 82%), but this difference was not significant. Overall, the authors concluded that kinematically aligned TKAs showed excellent results over a 13-year period that were similar to those of mechanically aligned TKAs. According to this report, it seems that both techniques are safe and effective options. Dowsey MM, Brown WA, Cochrane A, Burton PR, Liew D, Choong PF. Effect of bariatric surgery on risk of complications after total knee arthroplasty: a randomized clinical trial. JAMA Netw Open. 2022 Apr 1;5(4):e226722. This RCT investigated the impact of bariatric surgery on TKA complications. The study involved 82 patients who underwent TKA due to osteoarthritis and had a BMI of ≥35 kg/m2. Patients were randomized into 2 groups: 1 undergoing bariatric surgery followed by TKA after a 20% reduction in baseline body weight for 1 year, and the other undergoing TKA along with general weight management advice. The bariatric surgery group experienced a significantly lower occurrence of complications as well as lower BMI compared with the TKA-only group. In conclusion, bariatric surgery prior to TKA in patients with advanced knee osteoarthritis and severe obesity decreased perioperative and postoperative complications when compared with TKA alone. This study highlights the potential benefits of addressing obesity through bariatric surgery before TKA as it can significantly reduce complications. Koster LA, Rassir R, Kaptein BL, Sierevelt IN, Schager M, Nelissen RGHH, Nolte PA. A randomized controlled trial comparing 2-year postoperative femoral and tibial migration of a new and an established cementless rotating platform total knee arthroplasty. Bone Joint J. 2023 Feb;105-B(2):148-57. This study of 61 TKA cases aimed to compare the migration of femoral and tibial components between 2 types of cementless rotating-platform TKA designs, Attune and Low Contact Stress (LCS) (both DePuy Synthes), 2 years after the surgical procedure. Radiostereometric analysis was used to evaluate the risk of aseptic loosening. Clinical and patient-reported outcome measures were also compared. The Attune femoral component exhibited significantly less migration than the LCS design, showing less subsidence, tilting, and (internal-external) rotation. Tibial component migration did not differ significantly between the 2 designs. At 2 years postoperatively, the rate of migration (femoral and tibial components) was minimal in both groups, suggesting stabilization. The Attune group reported less pain at rest during the entire follow-up period and better functional scores in certain measures. Overall, the authors concluded that the Attune design demonstrates favorable characteristics with regard to component migration and clinical outcomes. This report provides valuable information regarding both implants. The Attune design seems to have better results. Malaithong W, Tontisirin N, Seangrung R, Wongsak S, Cohen SP. Bipolar radiofrequency ablation of the superomedial (SM), superolateral (SL), and inferomedial (IM) genicular nerves for chronic osteoarthritis knee pain: a randomized double-blind placebo-controlled trial with 12-month follow-up. Reg Anesth Pain Med. 2022 Dec 21;48(4):151-60. This study aimed to assess the effectiveness of bipolar radiofrequency ablation as a treatment for knee osteoarthritis. There were 64 patients with knee osteoarthritis who had received substantial pain relief (>50%) from prognostic nerve blocks and were randomly assigned to 1 of 2 groups: (1) genicular nerve local anesthetic and corticosteroid injections with sham radiofrequency ablation, and (2) local anesthetic and corticosteroid with bipolar radiofrequency ablation. Both groups experienced significant VAS pain reduction at 12 months postoperatively (the primary end point), with no significant differences between them (p = 0.40). There were also no significant differences in WOMAC total, pain, stiffness, and function scores or Patient Global Improvement Index scores. The authors concluded that the efficacy of genicular nerve radiofrequency ablation was not demonstrated and suggested that more aggressive lesioning strategies targeting multiple nerves may be worth exploring in future investigations. This study suggests that bipolar radiofrequency ablation might not be an effective treatment for knee osteoarthritis, but further investigation is warranted. Mihalko WM, Johnson KC, Neiberg RH, Bahnson JL, Singhal K, Richey PA; Look AHEAD Research Group. The association of total knee arthroplasty with weight loss in the Look AHEAD (Action for Health in Diabetes) clinical trial. J Arthroplasty. 2023 Jun;38(6S):S81-87.e2. The study investigated the impact of TKA on weight loss in patients with obesity participating in a 10-year intensive lifestyle intervention or a diabetes support and education program; 4,624 participants were included in the final analysis. The intensive lifestyle intervention aimed to achieve a 7% weight loss through counseling. The analysis indicated that the intensive lifestyle intervention remained effective for maintaining or losing weight after TKA. Participants in the intensive lifestyle intervention group had a significantly higher percentage of weight loss compared with the diabetes support and education group, both before and after TKA. However, there was no significant difference in the percentage change in weight (from before to after TKA) between the intensive lifestyle intervention group and the diabetes support and education group. In conclusion, participants who had undergone a TKA could still adhere to weight loss goals and even lose more weight. Both intervention modalities appear to be equally effective for losing weight among patients who undergo TKA. Nagata N, Hiranaka T, Okamoto K, Fujishiro T, Tanaka T, Kensuke A, Kitazawa D, Kotoura K. Is simultaneous bilateral unicompartmental knee arthroplasty and total knee arthroplasty better than simultaneous bilateral total knee arthroplasty? Knee Surg Relat Res. 2023 Apr 27;35(1):12. This retrospective study aimed to assess the advantages of performing UKA on a single indicated side in patients undergoing simultaneous bilateral knee arthroplasty. The study compared 33 cases of simultaneous bilateral UKA and TKA with 99 cases of simultaneous bilateral TKA. The comparison involved factors such as blood CRP, albumin, and D-dimer, deep venous thrombosis incidence, range of motion, and clinical scores before and 1 year after the surgical procedure. Blood tests indicated that the UKA group had higher albumin levels on certain postoperative days and lower CRP and D-dimer levels on other postoperative days. The UKA group had significantly better postoperative flexion angles. Clinical scores did not differ significantly between the groups, but the UKA group exhibited a significantly lower incidence of deep venous thrombosis. This study suggested that when performing simultaneous bilateral knee arthroplasty, opting for UKA on 1 side and TKA on the other side (rather than 2 TKAs) could lead to better flexion angles, reduced surgical trauma, and lower deep venous thrombosis risk. When feasible, the use of UKA and TKA in patients undergoing simultaneous bilateral knee arthroplasty instead of bilateral TKA seems to be a better option. Zhou LB, Wang CC, Zhang LT, Wu T, Zhang GQ. Effectiveness of different antithrombotic agents in combination with tranexamic acid for venous thromboembolism prophylaxis and blood management after total knee replacement: a prospective randomized study. BMC Musculoskelet Disord. 2023 Jan 4;24(1):5. This study evaluated the effectiveness of different antithrombotic agents combined with tranexamic acid for venous thromboembolism prevention and blood management after TKA. A total of 180 patients undergoing a surgical procedure were divided into 3 groups receiving oral rivaroxaban, subcutaneous dalteparin sodium, or oral aspirin in conjunction with tranexamic acid. The aspirin group demonstrated superior outcomes, including lower post-treatment drainage volume, a lower transfusion rate, and fewer bleeding complications compared with the rivaroxaban and dalteparin sodium groups, whereas all 3 agents effectively prevented venous thromboembolism. This study emphasized the potential benefits of the aspirin-tranexamic acid combination in postoperative blood management and venous thromboembolism prophylaxis. Aspirin and tranexamic acid appear to be the best option.