Comparison of traditional PS versus kinematically designs in primary total knee arthroplasty
Purpose: Kinematically designed total knee arthroplasty (TKA) aims to restore normal kinematics by replicating the function of both cruciate ligaments. Traditional posterior-stabilized (PS) TKA designs, on the other hand, simplify knee kinematics and may improve TKA cost-effectiveness. The purpose of this study was to compare outcomes of patients who underwent primary TKA using either a traditional PS or kinematically designed TKA. Methods: This retrospective study examined all patients who underwent primary TKA using either a kinematically or a traditional PS designed TKA implant, with a minimum follow-up of 2 years. Patient demographics, complications, readmissions, revision rates and causes, range of motion (ROM) and patient reported outcomes (KOOS, JR) were compared between groups. Kaplan"“Meier survivorship analysis was performed to estimate freedom from revision, and multivariate regression was performed to control for confounding variables. Results: A total of 396 TKAs [173 (43.7%) with a kinematic design, 223 (56.3%) with a traditional design] with a mean follow-up of 3.48 ± 1.51 years underwent analysis. Revision rates did not differ between groups (9.8% vs. 6.7%, p = 0.418). In Kaplan"“Meier analysis at 2-year follow-up, freedom from all-cause revision (96.4% vs. 93.1%, p = 0.139) were similar between groups. The two cohorts had no significant difference in aseptic loosening at 2 years (99.6% vs. 97.1, p = 0.050) and at latest follow up (92.7% vs. 96.4%, p = 0.279). KOOS, JR scores and post-operative ROM were similar between groups. Conclusion: This study demonstrated similar mid-term outcomes following the use of both a kinematically designed and a traditionally designed implant in primary TKA patients. Level of evidence: Retrospective study"”III.
Effect of Marital Status on Outcomes Following Total Joint Arthroplasty
INTRODUCTION/BACKGROUND:The purpose of this study is to investigate whether the specific socioeconomic factor such as marital status has any effect on clinical outcomes and patient-reported outcome measures (PROMs) after primary total hip (THA) and knee (TKA) arthroplasty. MATERIALS AND METHODS/METHODS:We retrospectively reviewed patients who underwent primary THA or TKA from January 2019 to August 2019 who answered all PROM questionnaires. Both THA and TKA patients were separated into two groups based on their marital status at the time of surgery (married vs. non-married). Demographics, clinical data, and PROMs (FJS-12, HOOS, JR, KOOS, JR, and VR-12 PCS&MCS) were collected at various time-periods. Demographic differences were assessed using chi-square and independent sample t tests. Clinical data and mean PROMs were compared using multilinear regressions while accounting for demographic differences. RESULTS:This study included 389 patients who underwent primary THA and 193 that underwent primary TKA. In the THA cohort, 256 (66%) patients were married and 133 (34%) were non-married. In the TKA cohort, there were 117 (61%) married patients and 76 (39%) non-married patients. Length of stay was significantly shorter for married patients in both the THA (1.30 vs. 1.64; pâ€‰=â€‰0.002) and TKA (1.89 vs. 2.36; pâ€‰=â€‰0.024) cohorts. Surgical-time, all-cause emergency department visits, discharge disposition, and 90-day all-cause adverse events (readmissions/revisions) did not statistically differ between both cohorts. Both HOOS, JR and KOOS, JR score improvements from baseline to 1-year did not statistically differ for the THA and TKA cohorts, respectively. Although VR-12 PCS (pâ€‰=â€‰0.012) and MCS (pâ€‰=â€‰0.004) score improvement from baseline to 1-year statistically differed for the THA cohort, they did not for the TKA cohort. CONCLUSION/CONCLUSIONS:Total joint arthroplasty may yield similar clinical benefits in all patients irrespective of their marital status. Although some PROMs statistically differed among married and non-married patients, the differences are likely not clinically significant. Surgeons should continue to assess levels of psychosocial support in their patients prior to undergoing TJA to optimize outcomes. LEVEL OF EVIDENCE/METHODS:III, Retrospective Cohort Study.
Prior Instability is Strongly Associated With Dislocation After Isolated Head and Liner Exchange
BACKGROUND:Isolated head and liner exchange is an appealing alternative to a more extensive revision total hip arthroplasty in patients who have well-fixed components. Despite efforts to increase femoral offset and restore soft tissue tensioning, limited component revision may be associated with higher rates of postoperative instability. METHODS:(range, 18.2-46.7). The most common indications for surgery included acetabular liner wear in 86 hips (41%), instability in 40 hips (19%), and infection in 36 hips (17%). RESULTS:increase, 95% CI 0.80-0.99, PÂ = .046). CONCLUSION/CONCLUSIONS:In a large cohort of patients who had isolated head and liner exchange, patients who had prior instability had 7-fold elevated odds of postoperative dislocation. This risk remains significant after controlling for cup positioning outside the Lewinnek safe zone, liner type, head size, neck length, soft tissue compromise, neuromuscular disease, and dual mobility constructs. LEVEL OF EVIDENCE/METHODS:III, retrospective cohort study.
The Impact of Machine Learning on Total Joint Arthroplasty Patient Outcomes: A Systemic Review
BACKGROUND:Supervised machine learning techniques have been increasingly applied to predict patient outcomes after hip and knee arthroplasty procedures. The purpose of this study was to systematically review the applications of supervised machine learning techniques to predict patient outcomes after primary total hip and knee arthroplasty. METHODS:A comprehensive literature search using the electronic databases MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials, and Cochrane Database of Systematic Reviews was conducted in July of 2021. The inclusion criteria were studies that utilized supervised machine learning techniques to predict patient outcomes after primary total hip or knee arthroplasty. RESULTS:Search criteria yielded n = 30 relevant studies. Topics of study included patient complications (n = 6), readmissions (n = 1), revision (n = 2), patient-reported outcome measures (n = 4), patient satisfaction (n = 4), inpatient status and length of stay (LOS) (n = 9), opioid usage (n = 3), and patient function (n = 1). Studies involved TKA (n = 12), THA (n = 11), or a combination (n = 7). Less than 35% of predictive outcomes had an area under the receiver operating characteristic curve (AUC) in the excellent or outstanding range. Additionally, only 9 of the studies found improvement over logistic regression, and only 9 studies were externally validated. CONCLUSION/CONCLUSIONS:Supervised machine learning algorithms are powerful tools that have been increasingly applied to predict patient outcomes after total hip and knee arthroplasty. However, these algorithms should be evaluated in the context of prognostic accuracy, comparison to traditional statistical techniques for outcome prediction, and application to populations outside the training set. While machine learning algorithms have been received with considerable interest, they should be critically assessed and validated prior to clinical adoption.
The impact of posterior-stabilized vs. constrained polyethylene liners in revision total knee arthroplasty
AIM/OBJECTIVE:Posterior stabilized (PS) and varus valgus constrained (VVC) knee polyethylene liners have been shown to confer excellent long-term functional results following revision total knee arthroplasty (rTKA). The purpose of this study was to compare outcomes of patients who underwent rTKA using either a PS or VVC liner. METHODS:A retrospective comparative study of 314 rTKA with either PS or VVC liner and a minimum follow-up time of two years was conducted. Patient demographics, complications, readmissions, and re-revision etiology and rates were compared between groups. Kaplan-Meier survivorship analysis was performed to estimate freedom from all-cause revision. RESULTS:Hospital LOS (3.41â€‰Â±â€‰2.49 vs. 3.34â€‰Â±â€‰1.93Â days, pâ€‰=â€‰0.793) and discharge disposition (pâ€‰=â€‰0.418) did not significantly differ between groups. At a mean follow-up of 3.55â€‰Â±â€‰1.60Â years, the proportion of patients undergoing re-revision did not significantly differ (19.1% vs. 18.7%, pâ€‰=â€‰0.929). In subgroup analysis of re-revision causes, the VVC cohort had superior survival from re-revision due to instability compared to the PS cohort (97.8% vs. 89.4%, pâ€‰=â€‰0.003). Freedom from re-revision due to aseptic loosening did not significantly differ between groups (85.2% vs. 78.8%, pâ€‰=â€‰0.436). Improvements in range of motion (ROM) from preoperative to latest follow-up were similar as well. CONCLUSIONS:PS and VVC liners confer similar survivorship, complication rates, and overall knee ROM in rTKA. VVC liners were not associated with increased postoperative aseptic loosening and demonstrated superior freedom from re-revision due to instability. Future studies with longer follow-up are warranted to better determine significant differences in clinical outcomes between the two bearing options. LEVEL III EVIDENCE/METHODS:Retrospective Cohort Study.
The accuracy of component positioning during revision total hip arthroplasty using 3D optical computer-assisted navigation
INTRODUCTION/BACKGROUND:Despite the excellent outcomes associated with primary total hip arthroplasty (THA), implant failure and revision continue to burden the healthcare system. The use of computer-assisted navigation (CAN) offers the potential for more accurate placement of hip components during surgery. While intraoperative CAN systems have been shown to improve outcomes in primary THA, their use in the context of revision total hip arthroplasty (rTHA) has not been elucidated. We sought to investigate the validity of using CAN during rTHA. METHODS:A retrospective analysis was performed at an academic medical institution identifying all patients who underwent rTHA using CAN from 2016-2019. Patients were 1:1 matched with patients undergoing rTHA without CAN (control) based on demographic data. Cup anteversion, inclination, change in leg length discrepancy (Î”LLD) and change in femoral offset between pre- and post-operative plain weight-bearing radiographic images were measured and compared between both groups. A safety target zone of 15-25Â° for anteversion and 30-50Â° for inclination was used as a reference for precision analysis of cup position. RESULTS:Eighty-four patients were included: 42 CAN cases and 42 control cases. CAN cases displayed a lower Î”LLD (5.74â€‰Â±â€‰7.0Â mm vs 9.13â€‰Â±â€‰7.9Â mm, pâ€‰=â€‰0.04) and greater anteversion (23.4â€‰Â±â€‰8.53Â° vs 19.76â€‰Â±â€‰8.36Â°, pâ€‰=â€‰0.0468). There was no statistical difference between the proportion of CAN or control cases that fell within the target safe zone (40% vs 20.9%, pâ€‰=â€‰ 0.06). Femoral offset was similar in CAN and control cases (7.63â€‰Â±â€‰5.84Â mm vs 7.14â€‰Â±â€‰4.8Â mm, pâ€‰= 0.68). CONCLUSION/CONCLUSIONS:Our findings suggest that the use of CAN may improve accuracy in cup placement compared to conventional methodology, but our numbers are underpowered to show a statistical difference. However, with a Î”LLD ofâ€‰~â€‰3.4Â mm, CAN may be useful in facilitating the successful restoration of pre-operative leg length following rTHA. Therefore, CAN may be a helpful tool for orthopedic surgeons to assist in cup placement and LLD during complex revision cases.
Discontinued Use of Outpatient Portable Intermittent Pneumatic Compression Devices May Be Safe for Venous Thromboembolism Prophylaxis in Primary Total Knee Arthroplasty Using Low-Dose Aspirin
Venous thromboembolism (VTE) is a rare, but serious complication following total knee arthroplasty (TKA). Current VTE guidelines recommend pharmacologic agents with or without intermittent pneumatic compression devices (IPCDs). At our institution, both 81-mg aspirin (ASA) twice a day (BID) and portable IPCDs were previously prescribed to TKA patients at standard risk for VTE, but the IPCDs were discontinued and patients were treated with ASA alone going forward. The aim of this study is to determine if discontinued use of outpatient IPCDs is safe and does not increase the rate of VTE or any other related complications in patients following TKA. A retrospective review of 2,219 consecutive TKA cases was conducted, identifying patients with VTE, bleeding complications, infection, and mortality within 90 days postoperatively. Patients were divided into two cohorts. Patients in cohort one received outpatient IPCDs for a period of 14 days (control), while those in cohort two did not (ASA alone). All study patients received inpatient IPCDs and were maintained on 81-mg ASA BID for 28 days. A posthoc power analysis was performed using a noninferiority margin of 0.25 (Î±â€‰=â€‰0.05; powerâ€‰=â€‰80%), which showed that our sample size was fully powered for noninferiority for our reported deep vein thrombosis (DVT) rates, but not for pulmonary embolism (PE) rates. A total of 867 controls and 1,352 patients treated with ASA alone were identified. Only two control patients were diagnosed with a PE (0.23%), while one patient in the ASA alone group had DVT (0.07%). There was no statistical difference between these rates (pâ€‰=â€‰0.33). Furthermore, no differences were found in bleeding complications (pâ€‰=â€‰0.12), infection (pâ€‰=â€‰0.97), or 90-day mortality rates (pâ€‰=â€‰0.42) between both groups. The discontinued use of outpatient portable IPCDs is noninferior to outpatient IPCD use for DVT prophylaxis. Our findings suggest that this protocol change may be safe and does not increase the rate of VTE in standard risk patients undergoing TKA while using 81-mg ASA BID.
Trends in Complications and Outcomes in Patients Aged 65 Years and Younger Undergoing Total Knee Arthroplasty: Data From the American Joint Replacement Registry
INTRODUCTION/BACKGROUND:The purpose of this study was to identify common complications and the rates of readmission and revision in total knee arthroplasty (TKA) patients younger than 65 years. METHODS:Using the American Joint Replacement Registry, we conducted a retrospective review of all TKAs done in patients aged 18 to 65 years from 2012 to 2020. Demographic factors such as age, sex, Charlson Comorbidity Index (CCI), and preoperative Veterans RAND 12-Item Health Survey Physical Component Summary (VR-12 PCS) scores were collected. We excluded patients older than 65 years and revision, oncologic, and nonelective cases. Primary outcomes included cumulative revision rate, 90-day readmission rate, and reason for revision. Univariate analysis and the Kaplan-Meier method were used. RESULTS:Six thousand one hundred seventy-nine patients were included. The average age was 58.8 years (SD 5.5 years), 61% were female, 82% were White, and 88% had a CCI of 0 (1 = 8% and â‰¥2 = 4%). The mean follow-up was 42.51 months. Seventy-four patients (1.2%) underwent revision. Sixty-nine patients (1.1%) were readmitted within 90 days. No factors assessed increased revision rates. Revision-free survivorship was 98.7% (95% CI 98.4 to 99.0) and 98.6% (95% CI 98.2 to 99.0) at 5 and 8 years, respectively. Infection (15%), aseptic loosening (14%), and instability (12%) were the most common indications for revision. CONCLUSION/CONCLUSIONS:TKA done in young and presumed active patients has excellent survivorship. Long-term follow-up is needed to assess survival trends in this growing population.
The effects of tourniquet on cement penetration in total knee arthroplasty
PURPOSE/OBJECTIVE:Aseptic loosening is a common cause of implant failure following total knee arthroplasty (TKA). Cement penetration depth is a known factor that determines an implant's "strength" and plays an important role in preventing aseptic loosening. Tourniquet use is thought to facilitate cement penetration, but its use has mixed reviews. The aim of this study was to compare cement penetration depth between tourniquet and tourniquet-less TKA patients. METHODS:A multicenter retrospective review was conducted. Patients were randomized preoperatively to undergo TKA with or without the use of an intraoperative tourniquet. The variables collected were cement penetration measurements in millimeters (mm) within a 1-month post-operative period, length of stay (LOS), and baseline demographics. Measurements were taken by two independent raters and made in accordance to the zones described by the Knee Society Radiographic Evaluation System and methodology used in previous studies. RESULTS:A total of 357 TKA patients were studied. No demographic differences were found between tourniquet (nâ€‰=â€‰189) and tourniquet-less (nâ€‰=â€‰168) cohorts. However, the tourniquet cohort had statistically, but not clinically, greater average cement penetration depth [2.4â€‰Â±â€‰0.6Â mm (range 1.2-4.1Â mm) vs. 2.2â€‰Â±â€‰0.5Â mm (range 1.0-4.3Â mm, pâ€‰=â€‰0.01)]. Moreover, the tourniquet cohort had a significantly greater proportion of patients with an average penetration depth within the accepted zone of 2Â mm or greater (78.9% vs. 67.3%, pâ€‰=â€‰0.02). CONCLUSION/CONCLUSIONS:Tourniquet use does not affect average penetration depth but increases the likelihood of achieving optimal cement penetration depth. Further study is warranted to determine whether this increased likelihood of optimal cement penetration depth yields lower revision rates.
Outcomes of isolated head-liner exchange versus full acetabular component revision in aseptic revision total hip arthroplasty
INTRODUCTION/UNASSIGNED:Isolated head and liner exchange in aseptic revision total hip arthroplasty (rTHA) is an appealing option rather than full acetabular component revision; however, early outcome reports suggest high rates of complications requiring re-revision. This study seeks to compare the outcomes of these procedures. METHODS/UNASSIGNED:This retrospective study assessed 124 head and liner exchanges and 59 full acetabular cup revisions conducted at a single center between 2011 and 2019 with at least 2 years of follow-up. Baseline demographics did not vary by group. Mean follow-up was 3.7 (range 2.0-8.6) years. RESULTS/UNASSIGNED:0.22) were associated with failure within 2 years. CONCLUSIONS/UNASSIGNED:In this analysis, 2-year outcomes for isolated head and liner exchange were non-inferior to full acetabular component revision. A future randomised prospective study should be conducted to better assess the optimal approach to revision in an aseptic failed hip arthroplasty.