Total knee arthroplasty survivorship and outcomes in young patients: a review of the literature and 40-year update to a longitudinal study.

INTRODUCTION: Growing numbers of younger patients are electing to undergo total knee arthroplasty (TKA) for end-stage osteoarthritis. The purpose of this study was to compare established literature regarding TKA outcomes in patients under age 55, to data from an ongoing longitudinal young patient cohort curated by our study group. Further, we aimed to provide a novel update on survivorship at 40 years post-TKA from our longitudinal cohort. METHODS: A literature search was conducted using the electronic databases PubMed, Embase, and Cochrane Library, using terms related to TKA, patients under age 55, and osteoarthritis. Demographic and outcome data were extracted from all studies that met the inclusion criteria. Data were divided into the "longitudinal study (LS) group," and the "literature review (LR) group" based on the patient population of the study from which it came. RESULTS: After screening, 10 studies met the inclusion criteria; 6 studies comprised the LR group, and 4 studies comprised the LS group. 2613 TKAs were performed among the LR group, and 114 TKAs were longitudinally followed in the LS group. The mean patient ages of the LR and LS groups were 46.1 and 51, respectively. Mean follow-up was 10.1 years for the LR group. Mean postoperative range of motion was 113.6° and 114.5° for the LR and LS groups, respectively. All-cause survivorship reported at 10 years or less ranged from 90.6% to 99.0%. The LS cohort studies reported survivorship ranges of 70.1-70.6% and 52.1-65.3% at 30 and 40 years, respectively. CONCLUSIONS: Young TKA patients demonstrated improved functionality at each follow-up time point assessed. Survivorship decreased with increasing lengths of follow-up, ultimately ranging from 52.1-65.3% at 40 years post-TKA. The paucity of literature on long-term TKA outcomes in this patient population reinforces the necessity of further research on this topic.

An Artificial Intelligence Chatbot is an Accurate and Useful Online Patient Resource Prior to Total Knee Arthroplasty.

BACKGROUND: Online information is a useful resource for patients seeking advice on their orthopaedic care. While traditional websites provide responses to specific frequently asked questions (FAQs), sophisticated artificial intelligence tools may be able to provide the same information to patients in a more accessible manner. Chat Generative Pretrained Transformer (ChatGPT) is a powerful artificial intelligence chatbot that has been shown to effectively draw on its large reserves of information in a conversational context with a user. The purpose of this study was to assess the accuracy and reliability of ChatGPT-generated responses to FAQs regarding total knee arthroplasty. METHODS: We distributed a survey that challenged arthroplasty surgeons to identify which of the 2 responses to FAQs on our institution's website was human-written and which was generated by ChatGPT. All questions were total knee arthroplasty-related. The second portion of the survey investigated the potential to further leverage ChatGPT to assist with translation and accessibility as a means to better meet the needs of our diverse patient population. RESULTS: Surgeons correctly identified the ChatGPT-generated responses 4 out of 10 times on average (range: 0 to 7). No consensus was reached on any of the responses to the FAQs. Additionally, over 90% of our surgeons strongly encouraged the use of ChatGPT to more effectively accommodate the diverse patient populations that seek information from our hospital's online resources. CONCLUSIONS: ChatGPT provided accurate, reliable answers to our website's FAQs. Surgeons also agreed that ChatGPT's ability to provide targeted, language-specific responses to FAQs would be of benefit to our diverse patient population.

The Financial Burden of Aspirin versus Oral Factor Xa Inhibitors for Thromboprophylaxis Following Total Knee Arthroplasty.

BACKGROUND: Aspirin and oral factor Xa inhibitor thromboprophylaxis regimens are associated with similarly low rates of venous thromboembolism following total knee arthroplasty (TKA). However, the rate of prosthetic joint infection (PJI) is lower with aspirin use. This study aimed to compare the cost differential between aspirin and factor Xa inhibitor thromboprophylaxis with respect to PJI management. METHODS: We used previously published rates of PJI following aspirin and factor Xa inhibitor thromboprophylaxis in primary TKA patients at a single, large institution. Prices for individual drugs were obtained from our hospital's pharmacy service. The cost of PJI included that of 2-stage septic revision, with or without the cost of 1-year follow-up. National data were obtained to determine annual projected TKA volume. RESULTS: The per-patient costs associated with a 28-day course of aspirin versus factor Xa inhibitor thromboprophylaxis were $17.36 and $3,784.20, respectively. Including cost of follow-up, per-patient costs for a 28-day course of aspirin versus factor Xa inhibitors increased to $73,358.76 and $77,125.60, respectively. The weighted average per-patient costs for a 28-day course were $237.38 and $4,370.93, respectively. The annual cost difference could amount to over $14.1 billion in the United States by 2040. CONCLUSIONS: The per-patient cost associated with factor Xa inhibitor thromboprophylaxis is as much as 1,980.6% higher than that of an aspirin regimen due to increased costs of primary treatment, differential PJI rates, and high costs of management. In an era of value-based care, the use of aspirin is associated with major cost advantages.

Increased Rates of Tibial Aseptic Loosening in Primary Cemented Total Knee Arthroplasty With a Short Native Tibial Stem Design.

BACKGROUND: Emerging evidence has suggested that both obesity and a short, native tibial stem (TS) design may be associated with early aseptic loosening in total knee arthroplasty. The use of short, fully cemented stem extensions may mitigate this risk. As such, we devised a multicenter study to confirm or negate these claims. METHODS: A search of our institutional research databases was done. A minimum 2-year time from index procedure was selected. Cohorts were created according to patient body mass index and the presence (stemmed tibia [ST]) or absence (nonstemmed tibia [NST]) of a short TS extension. Kaplan-Meier survival analyses for aseptic loosening and log-rank tests were done. RESULTS: A total of 1,350 patients were identified (ST = 500, NST = 850). The mean time to the final follow-up in cases without aseptic loosening for the ST cohort was 3.5 years (2.8-6.3) and 5.0 years (2.9-6.3) for the NST cohort (P < 0.001). Kaplan-Meier survival analysis at 6 years was superior for the ST cohort (100%, 98.5%; P = 0.025), and a trend toward superior 5-year survival was observed for body mass index <40 kg/m2 (99.1%, 93.2%; P = 0.066). The mean time to aseptic loosening was 2.4 years (0.9-4.5), with approximately 40% occurring within the first 2 years. CONCLUSIONS: Short, native TS design is associated with early aseptic loosening in primary cemented total knee arthroplasty. This can be mitigated through the use of an ST. More cost-effective solutions include (1) use of implants with longer native stem designs or (2) redesign of short TS implants.

Lack of small tibial component size availability for females in a highly utilized total knee arthroplasty system.

PURPOSE: Surgeons must rely on manufacturers to provide an appropriate distribution of total knee arthroplasty (TKA) sizes. There is a lack of literature regarding current appropriateness of tibial sizing schemes according to sex. As such, a study was devised assessing the adequacy of off-the-shelf tibial component size availability according to sex. METHODS: A search was conducted to identify all primary TKAs between July 2012 and June 2019 performed using a single implant. Baseline patient characteristics were collected (age, weight, height, BMI, and race). Two cohorts were created according to patient sex. Tibial sizes for each cohort were collected. Tibial component bar graph and histogram were created according to component sizes. Skewness and kurtosis were calculated for each distribution. Overhang was noted and measured radiographically. RESULTS: A total of 864 patients were identified, 38.7% males and 61.3% females. Most patients were Caucasian, and BMI was similar between cohorts. Tibial size distribution for males was as follows: 0.3% C, 4.8% D, 16.5% E, 40.1% F, 31.4% G, 6.9% H. Tibial size distribution for females was as follows: 30.8% C, 42.8% D, 23.0% E, 2.6% F, 0.8% G, 0.0% H. Histograms and normal curves demonstrated a fairly symmetric distribution of sizes for males (skewness = - 0.31, kurtosis = - 0.03). The distribution for females was positively skewed (skewness = 0.57, kurtosis = 0.12). Overall, overhang was noted in 16.6% of all size C tibias. CONCLUSIONS: The results of this study highlight an implant-specific discrepancy in size availability affecting female patients which could result in inferior outcomes. The authors urge manufacturers to critically assess current implant size distribution availability to ensure both genders are adequately, and equally represented. LEVEL OF EVIDENCE: IV.

Reduced Aseptic Loosening With Fully Cemented Short-Stemmed Tibial Components in Primary Cemented Total Knee Arthroplasty.

BACKGROUND: Recently, the use of short tibial stems in the obese population undergoing total knee arthroplasty (TKA) has been proposed. Thus, we designed a study to assess tibial component survivorship after primary TKA using a single implant both with and without a fully cemented stem extension performed by a single surgeon. METHODS: A search of our institutional research database was performed. A minimum 2-year follow-up was selected. Cohorts were created according to patient body mass index (BMI; >40 kg/m2 and <40 kg/m2) and the presence (stemmed tibia [ST]) or absence (non-stemmed tibia [NST]) of a short tibial stem extension. Kaplan-Meier survival analyses for aseptic loosening and log-rank tests were performed. RESULTS: A total of 236 patients were identified (ST = 162, NST = 74). Baseline patient characteristics were statistically similar between cohorts with the exception of BMI which was greater in the ST cohort (32.9 kg/m2, 30.6 kg/m2; P = .01). Kaplan-Meier survival analysis at 5 years was superior for the BMI < 40 kg/m2 cohort (98.9%, 93.1%; P = .045), the ST cohort (100%, 94.5%; P = .006), and the BMI > 40 kg/m2 with ST cohort at 4 years (71.4%, 100%; P = .008). CONCLUSION: Morbid obesity and a short native tibial stem design appear to be associated with aseptic loosening in primary TKA. This appears to be mitigated through the use of an ST. As such, the use of ST may be considered in at-risk patients. Alternatively, implants with longer native stem designs can be employed. Modern short-stemmed tibial components may need to be redesigned.