Primary Total Knee Arthroplasty Research Articles

Revision Total Knee Arthroplasty Achieves Minimal Clinically Important Difference Faster Than Primary Total Knee Arthroplasty

BackgroundRevision total knee arthroplasty (rTKA) remains underexplored regarding patient-reported outcome measures (PROMs), particularly in terms of time to reach minimal clinically important difference (MCID). This study addresses this gap by comparing the time to achieve MCID between primary TKA (pTKA) and rTKA patients, providing valuable insights into their recovery trajectories. MethodsA total of 8,266 TKAs (7,618 pTKA and 648 rTKA) were retrospectively studied in a multi-institutional arthroplasty registry. Patients who completed the patient-reported outcomes measurement information system (PROMIS) global physical, PROMIS physical function short form 10a (PF-10a), and knee injury and osteoarthritis outcome score physical function short form (KOOS-PS) questionnaires were identified by Current Procedural Terminology codes. Survival curves with and without interval censoring were utilized to evaluate the time to achieve MCID. ResultsComparing the time to achieve MCID, rTKAs were significantly faster than pTKA for PROMIS global physical (3.5 versus 3.7 months, P = 0.004) and KOOS-PS (3.3 versus 4.2 months, P < 0.001), but similar for PROMIS PF-10a (4.4 versus 4.8 months, P = 0.057). Interval censoring also showed similar trends with earlier times to achieve MCID for rTKAs for PROMIS global physical (0.6 to 0.61 versus 0.97 to 0.97 months, P = 0.009) and KOOS-PS (0.97 to 0.97 versus 1.47 to 1.47 months, P < 0.001), but not for PROMIS PF-10a (2.43 to 2.54 versus 1.90 to 1.91 months, P = 0.92). ConclusionsThe present study revealed that the time to achieve MCID was faster in patients undergoing rTKA compared to those undergoing pTKA. These findings allow surgeons to reassure preoperative rTKA patients that their recovery to a MCID postoperatively may be quicker than expected, especially when compared to their initial recovery after primary TKA. Level of EvidenceLevel III.

Tourniquet Use and Local Tissue Concentrations of Cefazolin During Total Knee Arthroplasty

Prophylactic administration of antibiotics before skin incision is an important component in the prevention of periprosthetic joint infection in arthroplasty surgery. For antibiotics to be effective, the local tissue concentration (LTC) must exceed the minimum inhibitory concentration of typical infecting organisms; however, the LTC of cefazolin during arthroplasty is poorly understood. To compare the systemic concentration of cefazolin in serum with the LTC in fat, synovium, and bone during primary total knee arthroplasty (TKA) while assessing the effect of tourniquet inflation. This prospective randomized clinical trial was conducted from March 1, 2022, to June 30, 2023, in patients undergoing TKA at a single academic center. Total knee arthroplasty with or without a limb tourniquet. Systemic blood and local tissues from the surgical site (fat, synovium, and bone) were harvested at regular intervals during the surgery. The primary outcome was the LTC of cefazolin, quantified using the liquid chromatography-tandem mass spectrometry technique. A total of 59 patients were included in the study, with 29 in the tourniquet group (mean [SD] age, 69.3 [9.6] years; 23 [79.3%] female) and 30 in the no tourniquet group (mean [SD] age, 69.9 [9.7] years; 21 [70.0%] female). In patients undergoing TKA without a tourniquet, the mean concentration of cefazolin in serum was 71.9 μg/mL (95% CI, 66.4-77.5 μg/mL), whereas the mean LTCs were 13.9 μg/g (95% CI, 12.1-15.7 μg/g) in fat, 27.7 μg/g (95% CI, 24.3-31.0 μg/g) in synovium, and 17.7 μg/g (95% CI, 14.8-20.5 μg/g) in bone. For patients undergoing TKA with a tourniquet, the mean concentration of cefazolin in serum was 72.0 μg/mL (95% CI, 66.3-77.7 μg/mL), and the mean LTCs were 9.9 μg/g (95% CI, 8.7-11.1 μg/g) in fat, 21.8 μg/g (95% CI, 18.7-25.0 μg/g) in synovium, and 13.0 μg/g (95% CI, 10.8-15.2 μg/g) in bone. The use of a tourniquet resulted in significantly lower mean LTCs by 60 minutes after cefazolin infusion (10.8 μg/g [95% CI, 9.1-12.4 μg/g] vs 16.9 μg/g [95% CI, 14.1-19.6 μg/g], P = .001 in fat; 18.9 μg/g [95% CI, 14.1-23.6 μg/g] vs 25.8 μg/g [95% CI, 21.4-30.3 μg/g], P = .03 in synovium; and 11.8 μg/g [95% CI, 9.3-14.2 μg/g] vs 19.4 μg/g [95% CI, 14.5-24.4 μg/g], P = .007 in bone). In this randomized clinical trial, the concentration of cefazolin was lower in local tissues (fat, synovium, and bone) than in systemic blood, and the use of a limb tourniquet further significantly reduced these concentrations. Although the current prophylactic dosing regimen for cefazolin provides sufficient serum concentrations, the levels in the periarticular tissue during TKA may be insufficient to prevent periprosthetic joint infection. ClinicalTrials.gov Identifier: NCT05604157.

The use of a tibial stem in primary total knee arthroplasty for patients with a frontal deformity of more than ten degrees reduces the rate of postoperative pain.

The use of a tibial stem for large deformities (> 10°) would reduce the incidence of pain. The aim of this study was to compare the effect of tibial stem on postoperative pain and aseptic loosening at the tibia in patients with a preoperative deformity > 10° in the frontal plane at 2years follow-up. This was a retrospective single-center case-control study. Ninety-eight patients with deformities greater than 10° in the frontal plane and a BMI > 30kg/m2 who had undergone posterior-stabilized (PS) total knee arthroplasty (TKA) with a tibial stem were matched using a propensity score to 98 patients who had undergone PS TKA without a tibial stem. The primary endpoint was the pain rate at 2years. The secondary endpoints were the rate of aseptic loosening of the tibia at 2years post-operatively. A significant difference was found in the rate of postoperative pain at 2years. It was higher in the group without tibial stem compared with the group with tibial stem (41.8% vs 17.3%, p = 0.0003). In the group without tibial stem, 24.4% of pain was mild, 61% moderate and no severe pain. In the tibial stem group, 47.1% of pain was mild, 41.2% moderate and no severe pain. A radiolucent line (RLL) was present at 2years in 26.5% of prostheses in the without tibial stem group and in 9.2% of prostheses in the tibial stem group (p = 0.002). There was no difference between the two groups in terms of aseptic loosening. The use of a tibial stem in primary TKA in patients with frontal deformities greater than 10° reduces postoperative pain and the presence of radiolucent lines.

Risk factors for failure of manipulation under anesthesia after total knee arthroplasty.

Manipulation under anesthesia (MUA) is a well-established treatment for stiffness after total knee arthroplasty (TKA). Risk factors for failure of MUA remain largely unknown. The primary aim of this study was to identify risk factors for failure of MUA after TKA. We performed a retrospective cohort study including 470 patients who underwent MUA after primary TKA with minimum 2year follow-up. Patients were grouped into success (n = 412) or failure (n = 58) cohorts; failure was defined as flexion < 90° at most recent follow-up or revision for stiffness. The increase in flexion post-MUA for the cohort was calculated. Several clinical, patient, and surgical factors were analyzed using univariate, followed by multivariable logistic regression models to identify independent risk factors associated with failure. The mean increase in flexion was 42° (range 0-115). BMI 30-35 (p = 0.01, odds ratio (OR) 2.42; 95% CI 1.25-4.68) and poorer pre-MUA flexion (p < 0.01, OR 1.43; 95% CI 1.23-1.67) were risk factors for failure. When considering revision for stiffness only, BMI 30-35 (p = 0.01, OR 3.27; 95% CI 1.41-7.61), lower pre-MUA flexion (p < 0.01, OR 1.43; 95% CI 1.18-1.75), and history of prior knee surgery (p = 0.04, OR 2.31; 95% CI 1.06-5.04) were predictors of failure. Time to MUA (p = 0.48), thromboprophylaxis (p = 0.44), pre-operative opioid use (p = 0.34), depression/anxiety (p = 1.0), and several other factors analyzed were not associated with failure. In this large cohort, elevated BMI and lower pre-MUA flexion were risk factors for failure of MUA. History of prior knee surgery was an additional predictor of requiring revision for stiffness.

Readmissions at 30 Days and 1 Year for Implant-Associated Complications Following Primary Total Hip and Knee Arthroplasty: A Population-Based Study of 34,392 Patients Across Austria

BackgroundThe primary aim of this study was to assess 30-day and 1-year rates for unplanned readmission due to implant-associated complications following total hip (THA) or total knee arthroplasty (TKA) in Austria. Secondary endpoints were reasons for readmission and differences in revision risk depending on demographics and hospital size. MethodsData on patients receiving THA (n = 18,508) or TKA (n = 15,884) in orthopaedic and trauma units across Austria within a 1-year period (January 2021 to December 2021) were retrieved from a government-maintained database. The absolute and relative frequencies of unplanned readmissions were calculated. Risk factors for 30-day and 1-year readmission following THA or TKA due to implant-associated complications were investigated. ResultsThe 30-day and 1-year readmission rates for any implant-associated complication were 1.0% (339 of 34,392) and 3.0% (1,024 of 34,392), respectively. Relative to the overall readmission rate for any complication at 30 days (n = 1,952) and 1 year (n = 12,109), readmission rates for implant-associated complications were 17.4 and 8.5%, respectively. The 30-day readmission rates were higher in THA (1.2%) than TKA patients (0.8%; P = 0.001), while it was the opposite at 1 year (THA, 2.7%; TKA, 3.3%; P < 0.001). Mechanical complications (554 of 1,024) were the most common reason for 1-year readmission. Prolonged length of in-hospital stay independently associated with increased 1-year readmission risk in THA and TKA patients. Treatment at large-sized hospitals was associated with a higher 1-year readmission risk in TKA patients. ConclusionsThe 30-day and 1-year readmission rates for implant-associated complications following THA or TKA in Austria are lower than reported in other countries, with similar risk factors and reasons for readmission. Considering that almost 20% of unplanned hospital readmissions following total joint arthroplasty are attributable to implant-associated complications, optimization of in-hospital and postdischarge medical care for these patients is warranted.

Improvements in Noise Symptoms, Forgotten Joint Scores, and Functional Outcomes With Greater Time Following Total Knee Arthroplasty

BackgroundTotal knee arthroplasty (TKA) is an impactful procedure with goals that include pain reduction and improved function, with low levels of prosthesis awareness. The purpose of this study was to determine if patients reported prosthetic noise and noise-related symptoms diminished over the course of time after TKA. MethodsThis study was a single institutional, retrospective study of patients who underwent primary unilateral TKA from 2018 to 2021. The TKAs were performed by four high-volume, fellowship-trained arthroplasty surgeons. Patients had similar baseline characteristics. Patients completed a survey consisting of four Likert scale questions related to prosthetic noise generation, the Forgotten Joint Score, and the Knee Injury and Osteoarthritis Outcome Score-Joint Replacement. Data were compared between patients who had undergone TKA one to two years earlier (N = 305) and those who had TKA three to four years prior to evaluation (N = 177). ResultsAfter more time with TKA, patients had significantly lower reports of hearing noise (31.1 versus 43.6%; P = 0.009) and feeling prosthetic noise-related symptoms (28.2 versus 40.3%; P = 0.010). Furthermore, after more time from TKA, patients had significantly higher satisfaction regarding noise-generation (65.5 versus 50.2%; P = 0.012), postoperative Knee Injury and Osteoarthritis Outcome Score-Joint Replacement scores (80.9 versus 75.9; P = 0.005), and Forgotten Joint Scores (65.4 versus 53.8; P < 0.001). ConclusionsAs more time passes after TKA, patients observe less prosthetic noise generation and have lower levels of prosthesis awareness and greater satisfaction than those who had surgery more recently. It is unclear whether these differences represent real improvement or acclimation to noise over time.

Effect of intraoperative cold solution irrigation to reduce postoperative pain in knee osteoarthritis patients who underwent unilateral primary total knee arthroplasty: a double-blinded randomized controlled trial

PurposeTo compare the postoperative pain score, opioid consumption, and blood loss in knee osteoarthritis patients who underwent unilateral primary total knee arthroplasty with and without intraoperative cold solution irrigation.MethodIn total, 70 knee osteoarthritis patients were randomly included in the study and allocated into 2 groups. The first group was irrigated intraoperatively with a cold solution and the second group was irrigated intraoperatively with a room-temperature solution.ResultsThe cold solution group showed significantly lower pain scores (numerical rating scale, NRS) at 28 h postoperatively (p = 0.047). There were no significant differences in opioid consumption or blood loss between the groups.ConclusionsIntraoperative cold solution irrigation in unilateral primary total knee arthroplasty patients may provide the benefit of early postoperative pain reduction for up to 28 h but has no effect in terms of reducing opioid consumption or blood loss.Trial registrationThe trial was registered in the Thai Clinical Trials Registry (TCTR) Trial registration number ID: TCTR20200706001 on 06/07/2020.

Total Knee Arthroplasty in Patients with Cerebral Palsy: A Large Database Analysis.

Cerebral palsy (CP) is a neurodevelopmental condition that can result in altered gait biomechanics, joint dysfunction, and imbalance. The complications associated with total knee arthroplasty (TKA) in patients with CP have not yet been well described. Therefore, our analysis sought to compare the 90-day and 2-year complications following TKA in patients with and without CP. The PearlDiver Mariner database was utilized to identify patients with CP undergoing primary TKA between 2010 and 2020. This cohort was matched 1:4 to a control cohort without neurodegenerative disorders based on age, sex, Elixhauser Comorbidity Index (ECI), tobacco use, obesity, and diabetes. A total of 3,257 patients (657 CP patients 2,600 controls) were included in our final analysis. A multivariable logistic regression analysis was utilized to determine the risk of CP on medical and surgical complications at 90 days and all-cause revision rates at 2 years. Patients with CP had an increased risk of acute kidney injury (odds ratio [OR]: 1.66; 95% confidence interval [CI]: 1.07-2.5; p = 0.019), pneumonia (OR: 5.63; 95% CI: 3.69-8.67; p < 0.001), urinary tract infection (OR: 5.01; 95% CI: 3.85-6.52; p < 0.001), and transfusion (OR: 2.21; 95% CI: 1.50-3.23; p < 0.001). CP patients additionally had a higher incidence of emergency department (ED) visits (OR: 5.24; 95% CI: 3.76-7.32; p < 0.001) and readmissions (OR: 5.24; 95% CI: 2.57-4.96; p < 0.001). There were no differences in rates of periprosthetic joint infection (PJI; OR: 1.23; 95% CI: 0.69-2.10; p = 0.463), surgical site infection (SSI; OR: 0.51; 95% CI: 0.12-1.46; p = 0.463), and reoperation (OR: 1.35; 95% CI: 0.71-2.43; p = 0.339) at 90 days postoperatively. The all-cause revision rates at 2 years were comparable (OR: 1.02; 95% CI: 0.67-1.51; p = 0.927). In this database review, we found that CP patients have a higher risk of medical complications in the acute postoperative period following TKA. The 90-day surgical complication and 2-year revision rates in CP patients were comparable to matched controls.

Patient-reported Physical and Mental Health Outcomes Following Lumbar Spinal Fusion versus Total Hip and Total Knee Replacement

BackgroundTotal hip and knee arthroplasty (THA/TKA) are reliable surgical procedures for alleviating pain and optimizing function. Spinal fusion has also been shown to be beneficial, however the comparative benefit of THA/TKA to lumbar spinal fusion is incompletely understood. MethodsThis study analyzed a single-center database of patients who underwent primary lumbar spinal fusion, elective primary TKA, or THA. PROMs included Veterans-Rand (VR12) Physical and mental component score (PCS/MCS) for TKA/THA and PROMIS (Patient-Reported Outcomes Measurement Information System) global mental and physical health (GPH/GMH) for spinal fusion. Results356 patients who underwent TKA, 290 underwent THA, and 125 underwent spinal fusion were included. Joint replacement patients were older, with higher body mass index in the TKA group. Spine patients had a lower improvement in physical health than the joint patients (TKA: 9.4 ± 11.2, THA: 15.2 ± 11.2, Spine: 6.2 ± 8.7, p<.001) and a lower proportion of patients reaching the minimal clinically important difference (MCID). Spine patients had higher GMH improvements compared to TKA patients (TKA: -1.1 ± 10.7, THA: 1.1 ± 11.9, Spine: 1.8 ± 8.4, p=.009) and the highest proportion of patients reaching the MCID. ConclusionSpinal fusion, total knee arthroplasty, and total hip arthroplasty all significantly improved PROMs at 1-year follow-up. At baseline, spinal fusion patients had better physical function scores and worse mental health scores compared to joint arthroplasty patients, while spinal fusion resulted in mean smaller gains in patient reported physical function and higher gains in patient reported mental health function compared to arthroplasty.

Feasibility of prehabilitation for patients awaiting total knee arthroplasty; a pilot study

ObjectiveTo examine the feasibility of conducting a preoperative home-based prehabilitation program for total knee arthroplasty patients at risk for delayed in-hospital recovery, and to explore the pre- and postoperative impact of this program. DesignA retrospective cohort study with matched controls, enabling subgroup analyses. SettingHome-based. SubjectsPatients awaiting primary unilateral total knee arthroplasty between 2019 and 2020, were compared with matched historic cases from 2016 to 2017. Matching criteria were scoring ≤17 points on the De Morton Mobility Index and >12.5 s on the timed-up-and-go test. InterventionSupervised home-based prehabilitation program versus no prehabilitation. OutcomesFeasibility, determined by recruitment rate, adherence, and safety of the program. Preoperative impact, assessed for the intervention group by differences in mean values for aerobic capacity, muscle strength and functional mobility between the first and last sessions. Postoperative impact was defined as the time needed to achieve in-hospital independence of physical function and was measured by the differences in mean values between the intervention and control groups. ResultsRecruitment rate was 71 %; adherence and drop-out rates were 88 % and 12 % respectively. No adverse events were reported. Preoperatively, the intervention group showed significant improvements in aerobic capacity on the 2-min walking test (84.29 m–98.06 m; p = 0.007) and 2-min step test (40.35 steps to 52.95 steps; p = 0.014), muscle strength on the 30 s chair stand test (7.3 stands to 10.1 stands; p = 0.002), and functional mobility as seen in the timed-up-and-go-test (19.52 s–15.85 s; p = 0.031). Postoperatively, the intervention group achieved in-hospital independence of physical function earlier (mean rank 16.11) than the control group (mean rank 24.89; p=<0.01). ConclusionsIt is feasible to conduct a prehabilitation program 4–6 weeks preoperatively, for high-risk patients awaiting total knee arthroplasty. Additionally, the program appears to have a positive impact on physical fitness both pre- and postoperatively.

Efficacy and Safety of Bone Wax Application at Different Time Points to Reduce Postoperative Blood Loss in Total Knee Arthroplasty: A Prospective Randomized Controlled Trial.

In addition to the surface hemorrhage of cancellous bone after large-area osteotomy, the intramedullary hemorrhage after the reamed knee joint is also a major cause of postoperative bleeding after total knee arthroplasty (TKA). This study evaluated the efficacy and safety of bone wax application at different time points of prone hemorrhage to reduce perioperative blood loss. From August 2023 to December 2023, 150 patients undergoing primary unilateral TKA were included in this prospective, randomized controlled trial, patients were randomly divided into three groups: group A, after autogenous osteotomy plug was used to fill the femoral medullary cavity, the residual space was sealed with bone wax and the exposed cancellous bone surface around the prosthesis was coated with bone wax after the prosthesis adhesion; group B, only the exposed cancellous bone surface around the prosthesis was coated with bone wax; and group C, no bone wax was used. The primary outcome was total perioperative blood loss. Secondary outcomes included occult blood loss, postoperative hemoglobin reduction, blood transfusion rate, lower limb diameter, and knee function, while length of hospital stay was recorded. Tertiary outcomes included the incidence of postoperative related adverse events. The total blood loss in group A (551.5 ± 224.5 mL) and group B (656.3 ± 267.7 mL) was significantly lower than that in group C (755.3 ± 248.3 ml, p < 0.001), and the total blood loss in group A was also lower than that in group B (p < 0.05). There were also significant differences in the reduction of hemoglobin level and hidden blood loss among the three groups (p < 0.05). However, there was no significant improvement in postoperative lower limb swelling, knee joint activity and hospitalization time; there was no significant difference in the incidence of complications such as thromboembolism. The use of bone wax in TKA can safely and effectively reduce perioperative blood loss and hemoglobin drop rate, and multiple use at time points during the operation when blood loss is prone to occur can produce more significant hemostatic effect.

Does previous total hip arthroplasty affect the outcomes of total knee arthroplasty? A one- and five-year follow-up registry study in a monocentric hospital

BackgroundOsteoarthritis in the lower extremities becomes more common as people age. In addition to conservative treatments, hip or knee arthroplasty is often needed. The aim of this study was to evaluate total knee arthroplasty (later TKA) in patients, comparing those who had previously undergone THA (later THA/TKA), with those who had not undergone such procedure. Pain, walking ability and functional capacity were assessed.MethodsPatients who underwent primary TKA between 1987 and 2017 at a single orthopaedic hospital was included in this study. The patients participated in clinical preoperative and postoperative examinations by an orthopaedic surgeon after one- and five- years. The final study group consisted of 418 patients who had undergone 502 knee arthroplasties. Of these 502 TKA cases, 462 had not undergone previous THA and 40 had undergone previous THA. To evaluate the patients’ physical function and walking ability, a structure form for knee arthroplasty based on the Hungerford score was used. The registry data from the Finnish National Institute of Health and Welfare was used. The data included TKA revision(s) and mortality events.ResultsAt the baseline and after one- and five- years primary TKA, no statistical differences were found in the total Hungerford score between TKA patients and THA/TKA patients. In both groups, the total score increased per surgery year. However, when analysing the relationship between the year of operation and the total score, no statistical differences were found between the groups (TKA and THA/TKA) at five years (p = 0.61). The only statistical difference found between the groups was in walking distance points after one year; THA/TKA patients (mean 83 [SD 17]) could walk remarkably shorter distances than TKA patients (91 [14]) one year after arthroplasty (p < 0.001).ConclusionsIn conclusion, walking distance improved more rapidly in TKA patients than in THA/TKA patients. However, patients who underwent more than one arthroplasty in their lower extremities managed their lives, activities, and pain almost as well as those who underwent only one knee arthroplasty.

In Vivo Intra-Articular Antibiotic Concentrations at 24 Hours After TKA Fall Below the Minimum Inhibitory Concentration for Most Bacteria: A Randomized Study of Commercially Available Bone Cement.

The use of antibiotic-loaded bone cement (ALBC) to help reduce the risk of infection after primary total knee arthroplasty (TKA) is controversial. There is a paucity of in vivo data on the elution characteristics of ALBC. We aimed to determine whether the antibiotic concentrations of 2 commercially available ALBCs met the minimum inhibitory concentration (MIC) and minimum biofilm eradication concentration (MBEC) for common infecting organisms. Forty-five patients undergoing TKA were randomized to receive 1 of the following: bone cement without antibiotic (the negative control; n = 5), a commercially available formulation containing 1 g of tobramycin (n = 20), or a commercially available formulation containing 0.5 g of gentamicin (n = 20). Intra-articular drains were placed, and fluid was collected at 4 and 24 hours postoperatively. An automated immunoassay measuring antibiotic concentration was performed, and the results were compared against published MIC and MBEC thresholds. The ALBC treatment groups were predominantly of White (65%) or Black (32.5%) race and were 57.5% female and 42.4% male. The mean age (and standard deviation) was 72.6 ± 7.2 years in the gentamicin group and 67.6 ± 7.4 years in the tobramycin group. The mean antibiotic concentration in the tobramycin group was 55.1 ± 37.7 μg/mL at 4 hours and 19.5 ± 13.0 μg/mL at 24 hours, and the mean concentration in the gentamicin group was 38.4 ± 25.4 μg/mL at 4 hours and 17.7 ± 15.4 μg/mL at 24 hours. Time and antibiotic concentration had a negative linear correlation coefficient (r = -0.501). Most of the reference MIC levels were reached at 4 hours. However, at 24 hours, a considerable percentage of patients had concentrations below the MIC for many common pathogens, including Staphylococcus epidermidis (gentamicin: 65% to 100% of patients; tobramycin: 50% to 85%), methicillin-sensitive Staphylococcus aureus (gentamicin: 5% to 90%; tobramycin: 5% to 50%), methicillin-resistant S . aureus (gentamicin: 5% to 65%; tobramycin: 50%), Streptococcus species (gentamicin: 10% to 100%), and Cutibacterium acnes (gentamicin: 10% to 65%; tobramycin: 100%). The aforementioned ranges reflect variation in the MIC among different strains of each organism. Gentamicin concentrations reached MBEC threshold values at 4 hours only for the least virulent strains of S . aureus and Escherichia coli. Tobramycin concentrations did not reach the MBEC threshold for any of the bacteria at either time point. The elution of antibiotics from commercially available ALBC decreased rapidly following TKA, and only at 4 hours postoperatively did the mean antibiotic concentrations exceed the MIC for most of the pathogens. Use of commercially available ALBC may not provide substantial antimicrobial coverage following TKA. Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Current Evidence Does Not Support the Use of Tibial Stem Extension in Total Knee Arthroplasty of Obese Patients: A Systematic Review

BackgroundObesity rates have been increasing globally, leading to a higher incidence of knee osteoarthritis and a surge in primary and revision total knee arthroplasty (TKA). The debate continues on the impact of obesity on TKA success, particularly regarding the use of stemmed tibial components in obese patients. This systematic review aimed to compare the effectiveness of stemmed tibial components versus standard keeled tibial components in obese patients undergoing TKA. MethodsA systematic review was conducted using databases including PubMed, Embase, Scopus, and Web of Science from inception to December 2023. The eligibility criteria were Participants: Patients who have obesity undergoing TKA; Intervention: stemmed TKA; Comparator: standard keeled tibial TKA; Outcomes: aseptic loosening, patient-reported outcome measures (PROMs), and overall revision. Data extraction and quality assessment were performed using the Newcastle-Ottawa Scale for cohort studies and the Cochrane risk-of-bias tool for randomized trials. ResultsThe search yielded 470 studies, with 10 studies (42,533 knees) meeting the inclusion criteria. These studies included 3 randomized controlled trials and 7 retrospective cohorts. The primary outcomes measured were aseptic loosening and overall revision rates, while secondary outcomes included PROMs. Results indicated mixed findings, with some studies suggesting improved outcomes with stemmed components in cases of aseptic loosening and mechanical failure, while others showed no significant difference. The PROMs did not show a significant difference between groups post-TKA. The certainty of the evidence was graded as “very low” using the Grading of Recommendations, Assessment, Development, and Evaluations framework. ConclusionsCurrent literature does not provide conclusive evidence to support the routine use of stemmed tibial components in TKA for obese patients. The decision to use stem extensions should not solely rely on the patient’s obesity status. Further high-quality studies are needed to clarify the role of stemmed components in TKA for this patient population. Level of EvidenceIII.

Dilution of humoral immunity: Results from a natural history study of healthy total knee arthroplasty patients.

The incidence of prosthetic joint infection (PJI) following elective primary total knee arthroplasty (TKA) is very low but serious risk remains. To identify unknown risk factors, we completed a natural history study of IgG specific forStaphylococcus aureus antigens previously phenotyped as protective (anti-Atl) and pathogenic (anti-Isd). Twenty-five male and 25 female optimized patients 50-85 years of age and BMI 24-39 undergoing primary TKA were prospectively enrolled. Blood sampling was performed preoperatively, postoperative Day 1, and at 2, 6, and 12 weeks, to assess serum cytokine, anti-staphylococcal IgG levels and anti-tetanus toxoid IgG measured via custom Luminex assay. Clinical, demographic, and PROMIS-10 data were collected with outcomes to 2 years postop. All participants completed the study and 2-year follow-up. No patients were readmitted or noted to develop a surgical site infection or serious adverse event, and patient-reported outcomes were improved. Serology revealed a highly significant decrease in six out of eight antibody titers against specific S. aureus antigens on Day 1 (p < 0.0001), five of which normalized to preoperative levels within 2 weeks. These changes were commensurate with a decrease and recovery of anti-tetanus toxoid titers, and a 20% drop in hemoglobin 13.8 ± 1.7 at preop to 11.1 ± 1.8 mg/dL on Day 1 (p < 0.0001). After TKA, a significant decrease in humoral immunity commensurate with blood loss and hemodilution was recorded. This decrease in circulating anti-staphylococcal antibodies in the early postop period may represent a periprosthetic joint infection risk factor for patients.

Rising Costs and Diminishing Surgeon Reimbursement From Primary to Revision Total Hip and Knee Arthroplasty: An Analysis of Medicare Advantage and Commercial Insurance.

Revision total joint arthroplasty (rTJA) is a resource-intensive procedure addressing failed primary total joint hip (total hip arthroplasty [THA]) and knee arthroplasty (total knee arthroplasty [TKA]). Despite predictions of increased demand, reimbursement for rTJA has not kept pace with increasing costs and may be insufficient compared with primary procedures. The study aimed to highlight the diminishing surgeon reimbursement between primary and revision THA (rTHA) and TKA. This study is a retrospective analysis of billing data for primary and rTHA and TKA procedures from a single institution between 2019 and 2022. Insurance claims and charges data were provided by a local affiliate of a major national carrier which includes Medicare Advantage (MA) and commercial patients. Using insurance data, the study evaluates the total surgery costs for primary and rTHA and TKA and the individual charges that make up the total surgery cost. Nine hundred five patients insured by the same carrier, who underwent a primary or rTJA, were identified. Irrespective of MA or commercial insurance, the average surgery cost for a primary THA was $26,043, compared with $53,456 for rTHA. Surgeon reimbursement for primary THA was 20% ($5,323) of the total surgery cost. Despite the doubled surgery cost for rTHA, surgeon reimbursement was 10% ($5,257) of the total surgery cost. Primary TKA surgery costs were $24,489, while revision costs were $43,074. Surgeon reimbursement for primary TKA was 20% ($4,918) of the total surgery cost, while reimbursement for revision TKA was 13% ($5,560). MA reimbursement was markedly lower than commercial reimbursement for primary and revision cases. Despite the higher total costs for rTJA, surgeon reimbursement is disproportionately diminished. The findings highlight the lack of incentive for revision cases. Surgeon reimbursement from MA and commercially insured patients for rTJA remains inadequate. This may limit patient access-to-care, leading to suboptimal outcomes and increased healthcare utilization.

Biomechanical study of effect of tibial posteromedial defect depth and area on primary TKA implant stability

BackgroundMedial tibial defects are common in patients who underwent primary total knee arthroplasty for varus deformity. Previous clinical studies have categorized tibial defects according to the depth of the defects and recommended different ways of addressing them. This study aimed to perform a biomechanical FE analysis to investigate the role of depth and surface area of the medial tibial plateau defects in the stability of the tibial component in primary TKA implants. MethodForty posteromedial tibial defect models with eight different depths (including 2, 4, 6, 8, 11, 13, 16, and 18 mm) and five different surface areas (including 10, 20, 30, 40, and 50% medial surface involvement) were used to create the FE models. Loads were applied to ellipses on tibial tray with 70–30% mediolateral distribution. The resulting relative motion of the bone and implant was measured to evaluate the tibial tray instability. ResultsFor defects with less than 20% surface involvement, the amount of relative motion had a moderately increasing fashion; however, in more significant percentages of surface involvement of the medial tibial plateau, especially in 50%, the graphs revealed a nonlinear increasing pattern which means that the depth would affect the amount of relative motion only when defect area is large. ConclusionIn defects with less than 20% surface involvement approaches like graft and cement augmentation would suffice whereas it would be essential to consider a more appropriate method like stem or metal augments for defects with more than 20% of medial surface involvement as the instability increased nonlinearly.

Comparable bone penetration between antibiotic-loaded and plain bone cement in total knee arthroplasty.

One of the main concerns around the use of antibiotic-loaded bone cement (ALBC) is the potential reduction in the mechanical properties of the cement when antibiotics are admixed. The purpose of this study was to determine whether there is a difference between plain cement and ALBC in terms of radiological intrusion into the bone in total knee arthroplasties (TKAs). Prospective randomized study of 80 consecutive patients who underwent TKA. Depending on the cement used, patients were divided into two groups by a computer-generated randomization programme: the cement without antibiotic (Group 1) or the ALBC (Group 2). Cement intrusion was measured in postoperative radiographs in eight different regions in the tibial component and six regions in the femoral component. The average cement intrusion was similar in both groups (p = nonsignificance [n.s.]). Group 1 (plain cement) had an average cement intrusion in the femur of 1.4 mm (±0.4) and 2.4 mm (±0.4) in the tibia. In Group 2 (ALBC), the average cement intrusion in the femur came to 1.6 (±0.5) and 2.4 mm (±0.5) in the tibia. In 80% of the patients, the cement intrusion in the tibia averaged a minimum of 2 mm, being similar in both groups (p = n.s.). There are no differences in bone intrusion when comparing plain cement to ALBC. Therefore, the use of ALBC in primary TKA may be indicated, achieving optimal bone penetration. Level I.

The Effect of Intravenous Tranexamic Acid on Perioperative Blood Loss, Transfusion Requirements, Verticalization, and Ambulation in Total Knee Arthroplasty: A Randomized Double-Blind Study.

Background and Objectives: Total knee arthroplasty (TKA) is sometimes associated with significant perioperative bleeding. The aim of this study was to determine the efficacy of tranexamic acid (TXA) in reducing perioperative blood loss in patients undergoing primary TKA. The secondary objectives were to assess the efficacy of TXA in reducing the need for blood transfusion in these patients and to determine its effect on verticalization and ambulation after TKA. Materials and Methods: This study included 96 patients who were randomly assigned to two groups, each containing 48 patients. The study group received intravenous TXA at two time points: immediately after the induction with doses of 15 mg/kg and 10 mg/kg 15 min before the release of the pneumatic tourniquet. The control group received an equivalent volume of 0.9% saline solution via the same route. Results: TXA markedly reduced (Z = -6.512, p < 0.001) the total perioperative blood loss from 892.56 ± 324.46 mL, median 800 mL, interquartile range (IQR) 530 mL in the control group, to 411.96 ± 172.74 mL, median 375 mL, IQR 200 mL, in the TXA group. In the TXA group, only 5 (10.4%) patients received a transfusion, while in the control group, 22 (45.83%) received it (χ2 = 15.536, p = 0.001). Patients in the study group stood (χ2 = 21.162, p < 0.001) and ambulated earlier postoperatively, compared to the control group (χ2 = 26.274, p < 0.001). Patients who received TXA had a better overall postoperative functional recovery. There was a statistically significant difference in all the above results. Conclusions: TXA is an effective drug for reducing the incidence of perioperative bleeding, decreasing transfusion rates, and indirectly improving postoperative functional recovery in patients undergoing primary TKA.

Tibial insert design significantly alters knee kinematics using a single cruciate-retaining total knee implant.

Patient dissatisfaction is not uncommon following primary total knee arthroplasty. One proposed method to alleviate this is by improving knee kinematics. Therefore, we aimed to answer the following research question: are there significant differences in knee kinematics based on the design of the tibial insert (cruciate-retaining (CR), ultra-congruent (UC), or medial congruent (MC))? Overall, 15 cadaveric knee joints were examined with a CR implant with three different tibial inserts (CR, UC, and MC) using an established knee joint simulator. The effects on coronal alignment, medial and lateral femoral roll back, femorotibial rotation, bony rotations (femur, tibia, and patella), and patellofemoral length ratios were determined. No statistically significant differences were found regarding coronal alignment (p = 0.087 to p = 0.832). The medial congruent insert demonstrated restricted femoral roll back (mean medial 37.57 mm; lateral 36.34 mm), while the CR insert demonstrated the greatest roll back (medial 42.21 mm; lateral 37.88 mm; p < 0.001, respectively). Femorotibial rotation was greatest with the CR insert with 2.45° (SD 4.75°), then the UC insert with 1.31° (SD 4.15°; p < 0.001), and lowest with the medial congruent insert with 0.8° (SD 4.24°; p < 0.001). The most pronounced patella shift, but lowest patellar rotation, was noted with the CR insert. The MC insert demonstrated the highest level of constraint of these inserts. Femoral roll back, femorotibial rotation, and single bony rotations were lowest with the MC insert. The patella showed less shifting with the MC insert, but there was significantly increased rotation. While the medial congruent insert was found to have highest constraint, it remains uncertain if this implant recreates native knee kinematics or if this will result in improved patient satisfaction.