Efficacy of revision surgery for the dislocating total hip arthroplasty: report from a large community registry.

BACKGROUND: Historically, achieving stability for the unstable total hip arthroplasty (THA) with revision surgery has been achieved inconsistently. Most of what we know about this topic comes from reports of high-volume surgeons' results; the degree to which these results are achieved in the community is largely unknown, but insofar as most joint replacements are done by community surgeons, the issue is important. QUESTIONS/PURPOSES: We used a community joint registry to determine: (1) the frequency of repeat revision after surgery to treat the unstable THA; (2) what surgical approaches to this problem are in common use in the community now; (3) are there differences in repeat revision frequency that vary by approach used; and (4) has the frequency of repeat revision decreased over time as surgical technique and implant options have evolved? METHODS: We reviewed 6801 primary THAs performed in our community joint registry over the last 20 years. One hundred eighteen patients (1.7%) with a mean age of 67 years were revised within the registry for instability/dislocation. Failure was defined as a return to the operating room for rerevision surgery for instability. Minimum followup was 2 years (average, 9.4 years; range, 2-20 years) with six patients having incomplete followup. The frequency of rerevisions was calculated and compared using Pearson's chi-square test. Cumulative rerevision rates were calculated using the Kaplan-Meier method and types of revision procedures were compared using the log-rank test. RESULTS: The initial revision procedure was successful in 108 patients (92%); 10 patients underwent repeat surgery for recurrent dislocation after their initial revision surgery. The most frequently performed procedure was revision of the head and liner only (35 of 118 [30%]); constrained devices were used in 19% (22 of 118) of the procedures. There was no difference in the cumulative rerevision rates for instability or dislocation by type of revision procedure performed. Six of 22 constrained liners were rerevised for varying indications. There was no difference in frequency of repeat revision for instability between those patients revised for THAs performed before 2003 and those managed more recently. CONCLUSIONS: Revision surgery for unstable THA is successfully managed in the community with a variety of surgical interventions. Identifying the reason for dislocation and addressing the source remain paramount. Constrained liners should be used with caution; although typically used in the most problematic settings, rerevision for a variety of failure modes remains troublesome. LEVEL OF EVIDENCE: Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

In-vivo alignment comparing patient specific instrumentation with both conventional and computer assisted surgery (CAS) instrumentation in total knee arthroplasty.

Patient specific instrumentation (PSI) was developed to increase total knee arthroplasty (TKA) accuracy and efficiency. The study purpose was to compare immediate post-operative mechanical alignment, achieved using PSI, with conventional and computer assisted surgery (CAS) instruments in high volume TKA practices. This prospective, multicenter, non-randomized study accrued 66 TKA patients using PSI. A computed tomography (CT) based algorithm was used to develop the surgical plan. Sixty-two percent were females, 99% were diagnosed with osteoarthritis, average age at surgery was 66 years, and 33 was the average body mass index. A historical control group was utilized that underwent TKA using conventional instruments (n=86) or CAS (n=81), by the same set of surgeons. Postoperative mechanical alignment was comparable across the groups. Operative time mean and variance were significant.

Early Clinical and Economic Outcomes for the VELYS Robotic-Assisted Solution Compared with Manual Instrumentation for Total Knee Arthroplasty.

Robotic-assisted total knee arthroplasty (TKA) has been developed to improve functional outcomes after TKA by increasing surgical precision of bone cuts and soft tissue balancing, thereby reducing outliers. The DePuy Synthes VELYS robotic-assisted solution (VRAS) is one of the latest entrants in the robotic TKA market. Currently, there is limited evidence investigating early patient and economic outcomes associated with the use of VRAS. The Premier Healthcare Database was analyzed to identify patients undergoing manual TKA with any implant system compared with a cohort of robotic-assisted TKAs using VRAS between September 1, 2021 and February 28, 2023. The primary outcome was all-cause and knee-related all-setting revisits within 90-day post-TKA. Secondary outcomes included number of inpatient revisits (readmission), operating room time, discharge status, and hospital costs. Baseline covariate differences between the two cohorts were balanced using fine stratification methodology and analyzed using generalized linear models. The cohorts included 866 VRAS and 128,643 manual TKAs that had 90-day follow-up data. The rates of both all-cause and knee-related all-setting follow-up visits (revisits) were significantly lower in the VRAS TKA cohort compared with the manual TKA cohort (13.86 vs. 17.19%; mean difference [MD]: -3.34 [95% confidence interval: -5.65 to -1.03] and 2.66 vs. 4.81%; MD: -2.15 [-3.23 to -1.08], respectively, p-value < 0.01) at 90-day follow-up. The incidence of knee-related inpatient readmission was also significantly lower (53%) for VRAS compared with manual TKA. There was no significant difference between total cost of care at 90-day follow-up between VRAS and manual TKA cases. On average, the operating room time was higher for VRAS compared with manual TKA (138 vs. 134 minutes). In addition, the discharge status and revision rates were similar between the cohorts. The use of VRAS for TKA is associated with lower follow-up visits and knee-related readmission rates in the first 90-day postoperatively. The total hospital cost was similar for both VRAS and manual TKA cohort while not accounting for the purchase of the robot.

Systematic review and meta-analysis of economic and healthcare resource utilization outcomes for robotic versus manual total knee arthroplasty.

The introduction of robotics in orthopedic surgery has led to improved precision and standardization in total knee arthroplasty (TKA). Clinical benefits of robotic versus manual TKA have been well established; however, evidence for economic and healthcare resource utilization outcomes (HRU) is lacking. The primary objective of this study was to compare economic and HRU outcomes for robotic and manual TKA. The secondary objective was to explore comparative robotic and manual TKA pain and opioid consumption outcomes. Multi-database literature searches were performed to identify studies comparing robotic and manual TKA from 2016 to 2022 and meta-analyses were conducted. This review included 50 studies with meta-analyses conducted on 35. Compared with manual TKA, robotic TKA was associated with a: 14% reduction in hospital length of stay (P = 0.022); 74% greater likelihood to be discharged to home (P < 0.001); and 17% lower likelihood to experience a 90-day readmission (P = 0.043). Robotic TKA was associated with longer mean operating times (incision to closure definition: 9.27 min longer, P = 0.030; general operating time definition: 18.05 min longer, P = 0.006). No differences were observed for total procedure cost and 90-day emergency room visits. Most studies reported similar outcomes for robotic and manual TKA regarding pain and opioid use. Coupled with the clinical benefits of robotic TKA, the economic impact of using robotics may contribute to hospitals' quality improvement and financial sustainability. Further research and more randomized controlled trials are needed to effectively quantify the benefits of robotic relative to manual TKA.

Resource utilization and costs for robotic-assisted and manual total knee arthroplasty - a premier healthcare database study.

INTRODUCTION: The impact of robotic-assisted total knee arthroplasty (rTKA) vs. traditional, manual TKA (mTKA) on hospital costs is not well documented and is analyzed herein. RESEARCH DESIGN AND METHODS: Patients in the Premier billing Healthcare Database undergoing elective rTKA or mTKA ("index') in the in- or outpatient setting for knee osteoarthritis between Oct 1st, 2015, to September 30th, 2021, were identified. Variables included patient demographics and comorbidities and hospital characteristics. Matched rTKA vs. mTKA cohorts were created using direct (on provider characteristics, age, gender, race and Elixhauser index) and propensity score matching (fixation type, comorbidities). Index and 90-day inflation-adjusted costs and healthcare utilization (HCU) were analyzed for both cohorts, using generalized linear models. RESULTS: 16,714 rTKA patients were matched to 51,199 mTKA patients. Average 90-day hospital cost reached $17,932 and were equivalent for both cohorts (rTKA vs. mTKA: $132 (95% confidence interval; -$19 to $284). There was a 2.7% (95%CI: 2.2%-3.3%) increase in home or home health discharge, and a 0.4% (95%CI: 0%-0.8%) decrease in 90-day hospital knee related re-visit in the rTKA vs. mTKA group. CONCLUSIONS: Cost-neutrality of rTKA vs. mTKA was observed, with a potential for lowered immediate post-operative HCU in the rTKA vs. mTKA cohorts.

Outcomes of the First 1,000 Total Hip and Total Knee Arthroplasties at a Same-day Surgery Center Using a Rapid-recovery Protocol.

BACKGROUND: Outpatient (<24 hour stay) total joint arthroplasty (TJA) has emerged as an alternative to traditional inpatient TJA. Patient-reported outcomes in the past have revealed favorable comparisons with inpatient controls. However, a higher outpatient TJA readmission rate has been reported. The goal of our study is to report outcomes, readmissions, and unplanned access to care data on the first 1,000 TJAs performed at a de novo ambulatory surgery center (ASC). METHODS: From March 2014 to May 2016, a consecutive series of 1,000 primary, total hip, and total knee arthroplasties (TKAs) were performed at a same-day surgical center. All patients were ≤66 years old, met the ASC inclusion criteria, and received preoperative training. All patients were discharged <24 hours after surgery to postoperative care suites. Oxford scores, visual analog scale for pain, patient satisfaction, ambulation, complication, and adverse events data were collected. RESULTS: A consecutive series of 543 TKAs and 457 total hip arthroplasties (THAs) were performed. Mean age was 57.2 years (range 28 to 66 years). The TKA patients consisted of 55.2% women, whereas THA patients consisted of 45.3% women. Overall infection rate was 0.8%. Hospital readmission rate was 1.5%, and early/unplanned access to care was 11.7%. Oxford Knee and Oxford Hip scores showed 15.7 and 21.1 point improvements, respectively, whereas pain scores improved 71% for TKA and 81% for THA at 6 months postoperatively (P < 0.01). CONCLUSIONS: Our immediate and short-term complications, readmissions, and outcomes for all patients compared favorably with published inpatient data. This study provides baseline data for quality metrics and functional outcomes for ASC-based total joint procedures.

Risk of revision following total hip arthroplasty: metal-on-conventional polyethylene compared with metal-on-highly cross-linked polyethylene bearing surfaces: international results from six registries.

The results of randomized controlled trials and systematic reviews have suggested reduced radiographic wear in highly cross-linked polyethylene compared with conventional polyethylene in primary total hip arthroplasty. However, longer-term clinical results have not been thoroughly examined, to our knowledge. The purpose of this study was to compare the risk of revision for metal-on-conventional and metal-on-highly cross-linked total hip arthroplasty bearing surfaces with use of a distributed data network of six national and regional registries (Kaiser Permanente, HealthEast, the Emilia-Romagna region in Italy, the Catalan region in Spain, Norway, and Australia). Inclusion criteria were osteoarthritis as the primary diagnosis, cementless implant fixation, and a patient age of forty-five to sixty-four years. These criteria resulted in a sample of 16,571 primary total hip arthroplasties. Multivariate meta-analysis was performed with use of linear mixed models, with survival probability as the unit of analysis. The results of a fixed-effects model suggested that there was insufficient evidence of a difference in risk of revision between bearing surfaces (hazard ratio, 1.20 [95% confidence interval, 0.80 to 1.79]; p = 0.384). Highly cross-linked polyethylene does not appear to have a reduced risk of revision in this subgroup of total hip arthroplasty patients. Arthroplasties involving highly cross-linked polyethylene do not appear to have an increased risk of revision in this subgroup of total hip arthroplasty patients.

Effect of femoral head size on metal-on-HXLPE hip arthroplasty outcome in a combined analysis of six national and regional registries.

BACKGROUND: HXLPE (highly cross-linked polyethylene) has greater wear resistance compared with UHMWPE (ultra-high molecular weight polyethylene), which may contribute to improving the outcomes of total hip arthroplasty with a large femoral head. However, no information is available regarding the effect of femoral head size on the survivorship of HXLPE hip prostheses. The aim of the present study was to provide evidence regarding whether femoral head size has an effect on the risk of revision when an HXLPE liner is used on a metal head. METHODS: A distributed health data network was developed by the ICOR (International Consortium of Orthopaedic Registries). Six national and regional registries are participating in this network: Kaiser Permanente, HealthEast, the Emilia-Romagna region in Italy, the Catalan region in Spain, Norway, and Australia. Data from each registry were standardized and provided at an aggregate level for each of the variables of interest. Patients with osteoarthritis who were forty-five to sixty-four years of age and had undergone uncemented total hip arthroplasty were included in the present study. Analyses were performed on the basis of individual patient profiles, utilizing the variables collected from each registry. The outcome of interest was the time to the first revision (for any reason). Survival probabilities and their standard errors were extracted from each registry for each unique combination of the covariates and were combined through multivariate meta-analysis utilizing linear mixed models to compare survivorship for <32-mm, 32-mm, and >32-mm femoral head sizes. RESULTS: A total of 14,372 total hip arthroplasties were included in the study. The five-year rate of revision surgery varied from 1.9% to 3.2% among registries. The risk of revision did not differ significantly between <32-mm and 32-mm head sizes (HR [hazard ratio] = 0.91, 95% CI [confidence interval] = 0.69 to 1.19) or between >32-mm and 32-mm sizes (HR = 1.05, 95% CI = 0.70 to 1.55). CONCLUSIONS: The results of our study provide relevant data to orthopaedic surgeons deciding on the use of a larger articulation in a metal-on-polyethylene bearing. A larger head diameter should not be considered a detriment to device survival when an HXLPE liner is used. However, efforts to force the use of a large-size implant appear unsupported, as similar survivorship was observed for all head diameter groups.

International comparative evaluation of knee replacement with fixed or mobile non-posterior-stabilized implants.

BACKGROUND: Mobile-bearing total knee prostheses were designed to reduce wear and improve implant survivorship following total knee arthroplasty. However, the benefit of mobile-bearing total knee arthroplasty remains unproven. Both mobile-bearing and fixed-bearing total knee arthroplasty implants are available in posterior-stabilized and non-posterior-stabilized designs. With the latter, the implant does not recreate the function of the posterior cruciate ligament (PCL) with a posterior-stabilizing cam mechanism. The purpose of the present study was to compare mobile-bearing, non-posterior-stabilized devices with fixed-bearing, non-posterior-stabilized devices used in total knee arthroplasty through a novel multinational study design. METHODS: Through the use of a distributed health data network, primary total knee arthroplasties performed for osteoarthritis from 2001 to 2010 were identified from six national and regional total joint arthroplasty registries. Multivariate meta-analysis was performed with use of linear mixed models, with the primary outcome of interest being revision for any reason. Survival probabilities and their standard errors were extracted from each registry for each unique combination of the covariates. RESULTS: A total of 319,616 patients (60% female) underwent non-posterior-stabilized total knee arthroplasty. A fixed-bearing, non-posterior-stabilized design was used in 258,190 (81%) of the knees and a mobile-bearing, non-posterior-stabilized design in 61,426 (19%) of the knees. Sixty-nine percent of the patients who received a fixed-bearing implant were over sixty-five years of age, compared with 63% of those who received a mobile-bearing implant. Mobile-bearing designs had a higher risk of revision, with a hazard ratio of 1.43 (95% confidence interval, 1.36 to 1.51; p < 0.001). CONCLUSIONS: Previous comparisons of mobile-bearing and fixed-bearing total knee arthroplasty outcomes have been inconclusive. The current study utilized an advanced, harmonized distributed analysis of six national and regional joint-replacement registries. To our knowledge, it is the largest analysis of mobile-bearing total knee arthroplasty to date. Mobile-bearing, non-posterior-stabilized designs presented a greater risk of failure than was found for fixed-bearing, non-posterior-stabilized designs. Caution should be used in the selection of the mobile-bearing non-posterior-stabilized design for total knee replacement.

Range of motion and stability in total hip arthroplasty with 28-, 32-, 38-, and 44-mm femoral head sizes.

The purpose of this study was to evaluate, via experimental models, the effect of larger head sizes for total hip arthroplasty on the type of impingement, range of motion (ROM), and joint stability. Testing was conducted using an anatomic full-size hip model (anatomic goniometer) and a novel anatomic dislocation simulator with 28-, 32-, 38-, and 44-mm diameter femoral heads within a 61-mm acetabular shell. Femoral heads >32-mm provided greater ROM and virtually complete elimination of component-to-component impingement. A significant increase in both flexion before dislocation and displacement between the femoral head and acetabulum to produce dislocation occurred with femoral heads >32-mm in diameter. These data indicate that larger femoral heads offer potential in providing greater hip ROM and joint stability.

Effect of radiation, heat, and aging on in vitro wear resistance of polyethylene.

Radiation cross-linking increases the wear resistance of polyethylene used in total hip replacement. Radiation also generates residual free radicals, which are detrimental to long-term properties of polyethylene. Two approaches are used to stabilize the residual free radicals and terminally sterilize the components. One is postirradiation annealing with gas sterilization and the other is postirradiation melting with gamma sterilization in nitrogen. The hypothesis of the current study is that postirradiation annealing followed by gamma sterilization in nitrogen will result in more free radicals in polyethylene than gamma sterilization either in air or in nitrogen alone. To test this hypothesis, concentration of residual free radicals was quantified in polyethylene that was annealed and gamma sterilized in nitrogen and control polyethylenes gamma sterilized in air versus in nitrogen. Three crosslinked polyethylenes that were melted and gas sterilized also were included in the study. The effects of residual free radicals were studied by accelerated aging. Oxidation levels and weight loss in bidirectional pin-on-disk tests were determined before and after aging. Polyethylene that was subjected to postirradiation annealing and gamma sterilization resulted in 58% more residual free radicals than control polyethylenes. Weight loss of the annealed polyethylene increased by 16-fold on accelerated aging and had three times higher oxidation levels than that measured in control polyethylenes after aging. In contrast, polyethylenes that were stabilized with postirradiation melting and terminally gas sterilized showed no detectable residual free radicals. Accelerated aging did not affect the weight loss and oxidation levels of melted polyethylenes.

Analysis of unicompartmental knee arthroplasty in a community-based implant registry.

Using a unique community implant and explant registry, long-term survival of unicompartmental knee arthroplasty was examined and compared with total knee arthroplasty (TKA) survival. All patients with unicompartmental knee arthroplasties done since September 1, 1991 were followed up prospectively to January 31, 2002 to assess survival and reason for revision. Five hundred sixteen unicompartmental knee arthroplasties of nine different designs were done by 23 surgeons. During this period, 39 of the 516 unicompartmental knee arthroplasties were revised. The major revision reasons for unicompartmental knee arthroplasties were progression of arthritis in the uninvolved compartments (51.3%), aseptic loosening (25.6%), and PE wear (20.5%). Kaplan-Meier survival analysis with revision as the end point revealed survival of 92.6% (range, 90.0%-95.2%) at 5 years for these unicompartmental knee arthroplasties and 88.6% (range, 85.0%-92.2%) at 10 years, compared with 94.8% (range, 93.5%-96.0%) at 10 years for primary TKAs. This community registry experience may more accurately reflect the results obtained in community practice, with different surgeons, varying indications, and numerous designs. The current study showed that revision of unicompartmental knee arthroplasties is done most commonly for progression of arthritis in the contralateral compartment, and at a higher rate than revision of primary cemented TKA.