Survivorship and Outcomes of Two-Stage Revision for Infected Total Hip Arthroplasty at a Mean of 7 Year Follow-Up.

PURPOSE: Periprosthetic joint infection (PJI) continues to be one of the leading causes of failure following total hip arthroplasty (THA). The objectives of the study were to: 1) determine the minimum 2-year infection-free survivorship of two-stage revision THA; 2) determine the causative organisms for repeat two-stage revision THA; and 3) characterize the results of failed two-stage revisions and evaluate patient-reported outcome measures (PROMs). METHODS: A retrospective chart review was completed for patients who underwent two-stage revision THA for PJI. Prospective data was collected on each patient, including demographics, causative organisms, complications, and type of reoperation. The PROMs, including Harris Hip Score (HHS), 12-item Short-Form Health Survey (SF-12), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores were obtained prior to two-stage revision THA surgery and annually as part of standard clinical and radiographic follow-up. RESULTS: A total of 328 patients who underwent a two-stage revision THA for a PJI were included in the study (mean age 67 years (range, 28 to 90), mean BMI of 30.6 (range, 15 to 57). The overall infection-free survivorship for two-stage revision THA was 73.8% at a minimum of 2 years (range, 2 to 20). Overall, 194 (59.1%) patients who had successful infection eradication underwent a two-revision THA only. The most common single organisms infected were Staphylococcus aureus (12.5%) and Staphylococcus epidermidis (11%). Higher reoperation rates were found in cases with MRSA and polymicrobial infections. All PROMs showed statistical improvement from pre-operatively to the latest follow-up appointment. CONCLUSIONS: Two-stage revision THA is associated with a good success rate in the treatment of PJIs at mid- to long-term follow-up. Polymicrobial and MRSA infections are poor prognostic factors, making the eradication of infection more difficult. The management of periprosthetic joint infections continues to be one of the most important orthopaedic challenges to treat.

Minimum 15-Year Survival of a Biconvex Inlay Patellar Component in Primary Total Knee Arthroplasty: An Analysis of 2,530 Total Knee Arthroplasties From a Single Institution.

BACKGROUND: Routine patellar resurfacing during primary total knee arthroplasty (TKA) remains controversial. To our knowledge, there are no studies reporting the long-term performance of a cemented biconvex all-polyethylene inlay component implanted at the time of primary TKA. The purpose of this study was to examine the 15-year survivorship and long-term clinical outcomes of this biconvex inlay patella used at our institution. METHODS: We retrospectively reviewed our prospectively collected institutional database and identified 2,530 patients who underwent cemented TKA with a single prosthetic design (from 1996 to 2007) where the patella was resurfaced using this cemented biconvex inlay patella. The mean age at surgery was 68 years (range, 29 to 93). The mean body mass index was 33.0 (range, 16.4 to 76.3), with 61.9% women. At the time of analysis, the mean time from surgery was 20.4 years (range, 15 to 26). We used Kaplan-Meier analysis to calculate survivorship at 15 years. We analyzed clinical outcomes using 3 patient-reported outcome measures collected prospectively. RESULTS: The 15-year survivorship with revision surgery for all causes as the end point was 97.1% (95% confidence interval 96.1 to 98.1%). The 15-year survivorship with revision surgery for a patella-related complication as the end point was 99.7% (95% confidence interval 99.4 to 1.0). At the final follow-up, patients showed significant improvement in scores for the Knee Society Clinical Rating System (P < .001), Western Ontario and McMaster University Osteoarthritis Index (P < .001), and Veterans Rand 12-Item Health Survey physical component (P < .001). CONCLUSIONS: Routine patellar resurfacing using a biconvex inlay patellar component has excellent survivorship and a low rate of complications at 15 years post-TKA.

Minimum 2-Year Outcomes of a Modern Monoblock Titanium Fluted Tapered Revision Stem for Complex Primary and Revision Total Hip Arthroplasty.

BACKGROUND: Modular titanium fluted tapered (TFT) stems have demonstrated excellent clinical success for femoral revision total hip arthroplasty (THA) surgery. This study reports the short-term outcomes of a novel modern monoblock TFT stem used for revision and complex primary THA with a minimum of 2 years of follow-up. METHODS: We identified 126 patients who received a single monoblock TFT stem: 26 patients for complex THA (failed fracture fixation) and 100 patients for revision THA. The reasons for revision THA included 40 for previous periprosthetic joint infection, 42 for aseptic loosening, 9 for trunnionosis, and 9 for periprosthetic fractures. The Paprosky grading for femoral bone loss at the time of surgery and the measured subsidence of femoral stems at 3-month follow-up were determined. We evaluated the number and indications for reoperations. RESULTS: The mean time from surgery was 3.9 years (range, 2.0 to 6.9). A paired t-test analysis showed significant improvement from preoperative versus postoperative clinical outcome scores (P < .001) for Harris Hip Score (38.76 ± 15.24 versus 83.42 ± 15.38), Western Ontario and McMaster Universities Arthritis Index (45.6 ± 19.0 versus 69.9 ± 21.3), Veterans RAND 12 Item Health Survey Physical component (31.7 ± 8.1 versus 37.8 ± 11.3), and Veterans RAND 12 Item Health Survey Mental component (48.2 ± 12.2 versus 51.6 ± 12.5). The Paprosky grading for femoral bone loss was Grade 1 (3.9%), Grade 2 (35.7%), Grade 3A (47.6%), Grade 3B (11.1%), and Grade 4 (1.6%) cases. There were 18 reoperations (14.7%), with 13 for periprosthetic joint infection (7 treated with implant retention and 6 treated with a 2-stage revision), 4 for instability, and 1 for acetabular aseptic loosening. There were no aseptic failures of the stem. CONCLUSIONS: This novel modern monoblock TFT stem provided reliable femoral fixation and has increasingly supplanted the use of modular TFT stems for complex primary and revision surgery in our institution.

Predictors of Undergoing Revision Within 5 Years of Total Knee Arthroplasty: A Population-Based Study.

BACKGROUND: The objective of this study was to identify the rate and risk factors for revision total knee arthroplasty (TKA) within the first 5 years postoperative. Our secondary objective was to identify the rate of additional surgical procedures and death. METHODS: We conducted a retrospective cohort study among patients in Ontario, Canada who underwent an elective, primary TKA between April 1, 2007, and March 31, 2014, for osteoarthritis. We excluded patients under 40 years and who had undergone a TKA within the previous 15 years. Our final study cohort included 94,193 patients. We reported the proportion of the study cohort who experienced revision surgery within 2 and 5 years of the primary TKA; secondary surgery within 5 years. We conducted Cochran-Armitage tests for trends to assess changes in the proportion of patients who experienced each of the study outcomes, and multivariable logistic regressions to evaluate predictors of a revision TKA. RESULTS: There were 3,112 (3.3%) patients who had a revision within 5 years, and 1,866 (2.0%) within 2 years of their primary TKA. 3,316 (3.5%) had a secondary surgery (0.6% patellar resurfacing; 1.6% manipulation; 1.3% synovectomy; 0.5% washout; 0.9% debridement). Lower age, men, lower income, higher comorbidity score, depression, previous arthroscopy, lower surgeon volume, and general anesthesia were all significant positive predictors of revision. CONCLUSIONS: In our study cohort, 2.0% of patients had a revision TKA within 2 years, and 3.3% within 5 years of their primary TKA. Preoperative identification of risk factors may reduce the future prevalence of revision TKAs.

Minimum 5-Year Clinical Outcomes and Survivorship for a Single Revision Total Knee Arthroplasty System Using Hybrid Fixation and Press-Fit Stems.

BACKGROUND: Hybrid fixation, utilizing diaphyseal press-fit stems and cement fixation in the tibial and femoral metaphyseal areas, has long been a strategy for revision total knee arthroplasty (rTKA). The purpose of this study was to evaluate the clinical outcomes and survivorships of hybrid fixation using a single rTKA revision system with a minimum of 5 years follow-up. METHODS: We reviewed our prospectively collected database to identify 281 patients who underwent rTKA using a single revision system with hybrid fixation and press-fit stems between July 2006 and August 2016. We reviewed the clinical outcome scores, including the Knee Society Score, Western Ontario and McMaster Universities Osteoarthritis index, and Veterans RAND 12 Item Health Survey. We also evaluated the 5 and 10-year survivorships and the indications for reoperations. The cohort had a mean age of 70 years (range, 45.2 to 92.0) and a mean body mass index of 33.4 (range, 17.3 to 55.8). The mean time from rTKA surgery was 11.1 years (range, 5.3 to 15.5). RESULTS: Paired t-test analyses showed significant improvements from preoperative versus postoperative clinical outcome scores (P < .001) for Knee Society Score, Western Ontario and McMaster Universities Osteoarthritis, and Veterans RAND 12 Item Health Survey Physical component. Prosthetic joint infections after index rTKA were the most common failure mode with 29 patients requiring reoperations. Rerevision due to aseptic loosening was uncommon (6 patients) with a cumulative survival rate of 95.2% at 5 years and 94.2% at 10 years. CONCLUSION: The use of this single rTKA system utilizing press fit stems combined with hybrid fixation provided significant improvements in the clinical outcomes and excellent survivorships at 5 and 10 years.

No Difference in Subsidence Between Modern Monoblock and Modular Titanium Fluted Tapered Femoral Stems.

BACKGROUND: Subsidence remains a concern when utilizing tapered fluted titanium (TFT) femoral stems and may lead to leg length discrepancy, impingement, instability, and failure to obtain osseointegration. This study aims to compare stem subsidence across 3 modern TFT stems. Our secondary aim was to investigate the influence of bicortical contact or "scratch fit" on subsidence, as well as the role of intraoperative imaging in maximizing bicortical contact and preventing stem subsidence. METHODS: A retrospective review of 271 hip arthroplasties utilizing modern TFT stems at a single institution was performed. Three stem designs were included in the analysis: 1 monoblock TFT stem (n = 91) and 2 modular TFT stems (n = 90; n = 90). Patient demographics, Paprosky femoral bone loss classification, bicortical contact, utilization of intraoperative imaging, and stem subsidence (comparison of initial postoperative radiograph to the latest follow-up radiograph-minimum 3 months) were recorded. RESULTS: There was no statistically significant difference in overall subsidence (P = .191) or the incidence of subsidence >5 millimeters between stems (P = .126). Subgroup analysis based on femoral bone loss grading showed no difference in subsidence between stems. Increased bicortical contact was associated with reduced subsidence (P = .004). Intraoperative imaging was used in 46.5% (126 of 271) of cases; this was not correlated with bicortical contact (P = .673) or subsidence (P = .521). CONCLUSION: All 3 modern TFT stems were highly successful and associated with low rates of subsidence, regardless of modular or monoblock design. Surgeons should select the stem that they feel is most clinically appropriate.

The Prevalence and Outcomes of Unexpected Positive Intraoperative Cultures in Presumed Aseptic Revision Knee Arthroplasty.

BACKGROUND: The prevalence and outcomes of unexpected positive intraoperative cultures (UPC) in presumed aseptic revision total knee arthroplasty (TKA) are unclear. The purpose of this study was to determine the prevalence of UPC and infection-free implant survival in this patient population. Secondly, we aimed to compare the infection-free implant survival between cohorts based on number of UPCs and antibiotic treatment. METHODS: We reviewed our institutional database from 2006 to 2019 for all TKA revisions (n = 1795) to identify all presumed aseptic TKA revisions with intraoperative culture(s). After exclusions, 775 revisions were eligible and those with UPC were included in the Kaplan-Meier analysis to determine infection-free implant survival for the cohorts. RESULTS: The prevalence of UPC was 9.8%. The 2- and 5-year infection-free survival was 97.4% and 95.3%, respectively. The 5-year infection-free survival from the same microorganism as the UPC was 98.7%. Infection-free survival was similar for the 1 versus ≥2 UPC cohorts (P = .416), however was poorer for the cohort treated with antibiotics (P = .021). Only one of 3 subsequent PJI-related implant failures was caused by the same microorganism (polymicrobial) as the UPC. There were no subsequent infections in patients with a single UPC not treated with antibiotics. CONCLUSIONS: The prevalence of UPC was 9.8% and the infection-free implant survival is excellent. Infection-free survivorship from PJI caused by the same UPC microorganism is outstanding. Comparisons between cohorts must be interpreted with caution due to study limitations. A single UPC in patents without other signs of infection does not require antibiotic treatment. LEVEL OF EVIDENCE: IV.

Effect of Osteochondroplasty on Time to Reoperation After Arthroscopic Management of Femoroacetabular Impingement: Analysis of a Randomized Controlled Trial.

Background: A subset of patients with femoroacetabular impingement (FAI) fail arthroscopic management. It is not clear which patients will fail surgical management; however, several surgical and patient factors, such as type of procedure and age, are thought to be important predictors. Purpose: This time-to-event analysis with a 27-month follow-up analysis compared the effect of (1) arthroscopic osteochondroplasty with or without labral repair versus (2) arthroscopic lavage with or without labral repair on the time to reoperation in adults aged 18 to 50 years with FAI. Study Design: Randomized controlled trial; Level of evidence, 1. Methods: Eligible participants had been randomized in a previous study trial to a treatment of arthroscopic osteochondroplasty or arthroscopic lavage with or without labral repair. Using the comprehensive data set from the Multinational Femoroacetabular Impingement Randomized controlled Trial, all reoperations until 27 months after surgery were identified. The analysis was conducted using a Cox proportional hazards model, with percentage of patients with a reoperation evaluated in a time-to-event analysis as the outcome. The independent variable was the procedure, with age and impingement subtype explored as potential covariates. The effects from the Cox model were expressed as the hazard ratio (HR). All tests were 2-sided, with an alpha level of .05. Results: A total of 108 patients in the osteochondroplasty group and 106 patients in the lavage group were included. The mean age of the patients included in the study was 36 ± 8.5 years. Overall, 27 incident reoperations were identified within the 27-month follow-up, with an incidence rate of 6 per 100 person-years. Within the osteochondroplasty group, 8 incident reoperations were identified (incidence rate, 3.4 per 100 person-years), while within the lavage group, 19 incident reoperations were identified (incidence rate, 8.7 per 100 person-years). The hazard of reoperation for patients undergoing osteochondroplasty was 40% of that of patients undergoing lavage (HR, 0.40 [95% CI, 0.17-0.91] P = .029). Conclusion: This study demonstrated that for adults between the ages of 18 and 50 years with FAI, arthroscopic osteochondroplasty was associated with a 2.5-fold decrease in the hazard of reoperation at any point in time compared with arthroscopic lavage. Registration: NCT01623843 (ClinicalTrials.gov identifier).

Unit Sales Trends of Hip Arthroplasty Procedures Performed in Ontario in 2020.

BACKGROUND: In March 2020, an emergency was declared in the province of Ontario owing to the COVID-19 pandemic. From March 19 to May 26, all elective total hip arthroplasty (THA) and total knee arthroplasty (TKA) procedures were deferred. The purpose of this study was to review the unit sales data of THA and TKA procedures in Ontario over this time period to identify any trends in surgical activity. METHODS: Unit sales data for all THA and TKA procedures performed in Ontario between January 2019 and December 2020 were reviewed. All orthopedic companies contributed to the data set. Femoral stems were considered an indicator of THA procedures, while primary femurs were considered an indicator of TKA procedures. Data were analyzed to determine trends in THA and TKA procedures during the deferral period and the relative change in THA and TKA activity following resumption. RESULTS: There was a 53% reduction in THA activity between March and May of 2020 when compared to the same interval in 2019. From June to September of 2019, THA sales activity was 87.3% that of TKA. From June to September of 2020, THA sales activity was 122.8% that of TKA. CONCLUSION: Provincial directives aimed at controlling the outbreak of COVID-19 contributed to a substantial reduction in THA and TKA activity in 2020. Compared to 2019, there was a disproportionate increase in THA compared to TKA activity in 2020 following resumption of surgical services. These data have implications in recovery planning for the surgical backlog of THA in Ontario.

Survivorship of Metaphyseal Cones and Sleeves in Revision Total Knee Arthroplasty.

BACKGROUND: Bone loss remains an anticipated challenge in revision total knee arthroplasty (rTKA). Recent efforts to enhance rTKA fixation and stability have focused on metaphyseal implants, namely cones and sleeves. We sought to compare cone and sleeve implant survivorship in rTKA. METHODS: One hundred eighty patients who underwent rTKA with metaphyseal implants from 2005 to 2018 were retrospectively reviewed. A total of 83 cones (22 femoral, 62 tibial) and 121 sleeves (58 femoral, 63 tibial) were identified. The mean age at the time of surgery was 72 years (range 43-97). Intraoperative Anderson Orthopaedic Research Institute bone loss classifications included the following: type 2A (25), type 2B (98), and type 3 (81). Mean follow-up was 41 months. RESULTS: Revision-free survival for cones was 91.3% vs 92.2% for sleeves (P = .29). Twelve knees (4 cones, 8 sleeves) underwent irrigation, debridement, and polyethylene exchange with metaphyseal implant retention for acute postoperative periprosthetic joint infection (PJI). Development of chronic PJI warranted removal of 7 cones (8.4%), 6 of which were initially placed as part of a 2-stage revision TKA. Eight sleeves (6.6%) were removed for PJI, with all initially placed during a second stage reimplantation. In the absence of infection, survival was 100% and 99.1% for cones and sleeves, respectively. One sleeve was revised for periprosthetic fracture. CONCLUSION: Metaphyseal cones and sleeves offer equally durable survivorship in revision TKA. PJI was the most common mode of implant failure in this series. Importantly, no cases of cone or sleeve aseptic loosening were observed.

Outcomes of Stemmed versus Un-Stemmed Varus-Valgus Constrained Components in Primary Total Knee Arthroplasty.

PURPOSE: The necessity of stemmed components when performing a varus-valgus constrained (VVC) primary total knee arthroplasty (TKA) is unclear. The purpose of this study is to compare the outcomes of primary VVC TKA with and without stems at a minimum of two years. METHODS: Patients in our prospectively collected database with primary VVC TKAs were identified. Patient demographics, prosthesis data, time in vivo, characteristics of revision, and radiographs and PROMs were compared between the stemmed and un-stemmed cohorts. RESULTS: Sixty-five patients with 69 primary VVC TKAs were identified; 17 were implanted with stems and 52 without stems. Five of the stemmed TKAs (5/17) required revision at 15.1 years, while only one of the un-stemmed TKA (1/52) required a revision at 21.6 years (p=0.003) for aseptic loosening. Of the 5 stemmed TKAs requiring revision, 3 were for aseptic loosening and 2 were for PPJI. The un-stemmed cohort had a significantly higher final total KSS (p=0.048). CONCLUSION: There was no increase in aseptic loosening or revision surgery in patients with non-stemmed primary VVC TKA compared to those with stemmed VVC TKA at mid-term follow-up. Utilizing non-stemmed TKA with VVC in appropriate cases is safe and may reduce cost, shorten operative time, and preserve bone-stock.

Iliopsoas Release: A Systematic Review of Clinical Efficacy and Associated Complications.

OBJECTIVE: To perform a systematic review of the findings of iliopsoas release as it relates to resolution of snapping, improvement of groin pain, and associated complications. DESIGN: Systematic review. DATA SOURCES: Four electronic databases PubMed/MEDLINE, EMBASE, CINAHL, and Web of Science were searched, identifying all literature pertaining to surgical treatment of a snapping hip/coxa saltans, iliopsoas impingement, or iliopsoas tendinitis. A total of 818 studies were identified. Two reviewers independently screened the titles, abstracts, and full-text articles for eligibility. ELIGIBILITY CRITERIA: All studies published in English that reported on iliopsoas release for snapping hip/coxa saltans, iliopsoas impingement, or iliopsoas tendinitis reporting outcomes or associated complications were eligible. RESULTS: A total of 48 articles were included in this review. Three surgical indications were identified for iliopsoas release, internal snapping hip, labral tear secondary to iliopsoas impingement, and iliopsoas tendinopathy after total hip arthroplasty. Arthroscopic techniques seemed to be superior to open techniques with regards to reoccurrence of snapping (5.1% vs 21.7%) and groin pain relief (89.1% vs 85.6%) with fewer complications (4.2% vs 21.1%) overall. CONCLUSIONS: Both open and arthroscopic iliopsoas releases have been shown to be successful treatment options regardless of the surgical indications identified in this review. Arthroscopic release demonstrated a decreased failure rate, fewer complications, and improved outcomes when compared with open procedures.

Midterm outcomes of total hip arthroplasty with a modular Birmingham head.

INTRODUCTION: Birmingham Hip Resurfacing (BHR) implants may be combined with a conventional femoral stem to create a modular metal-on-metal total hip arthroplasty (BHR MoM THA). There is little outcome data regarding this construct. This study examines midterm outcomes of BHR MoM THA compared to oxidised zirconium total hip arthroplasty (THA). METHODS: A retrospective institutional review identified all patients receiving BHR MoM THA between April 2005 and February 2011 and a matched control cohort of zirconium THA patients. Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Harris Hip Score (HHS), and SF-12 Health status scores were obtained. Revisions and complications were collected from clinical records. Radiographs were assessed for evidence of component malposition, loosening, osteolysis, or heterotopic ossification. RESULTS: 63 modular BHR MoM THA were identified in 61 patients (36 with BHR cups, 27 with R3 cups) and 63 zirconium THA in 58 matched controls. Mean follow-up was 58 months. 14 BHR MoM THA hips (22.2%) were revised (4 infections, 1 dislocation, 9 soft tissue reactions) compared to 3 (4.8%) zirconium THA (all infections). At latest follow-up, 18.4% of surviving BHR MoM THA hips were painful compared to 0.5% of zirconium THA controls (p < 0.001). WOMAC, HHS, and SF-12 did not differ significantly between surviving members of the 2 groups. DISCUSSION: BHR MoM THA demonstrated a high revision rate, largely for adverse local soft tissue reaction and pain. Among those not revised, many reported some residual pain despite similar quality of life measures to those who received zirconium THA.

Osteochondroplasty and Labral Repair for the Treatment of Young Adults With Femoroacetabular Impingement: A Randomized Controlled Trial.

BACKGROUND: Femoroacetabular impingement (FAI) is a condition known to cause hip pain in young adults. PURPOSE: To evaluate the efficacy of the surgical correction of FAI via arthroscopic osteochondroplasty with or without labral repair compared with arthroscopic lavage of the hip joint with or without labral repair. STUDY DESIGN: Randomized controlled trial; Level of evidence, 1. METHODS: A total of 220 male and female participants aged 18 to 50 years with nonarthritic FAI suitable for surgical treatment were recruited for the trial at 10 clinical centers in Canada, Finland, and Denmark between October 2012 and November 2017, of whom 214 were included in the final analysis. In the osteochondroplasty group, cam- and/or pincer-type lesions were resected using fluoroscopic guidance. In the lavage group, the joint was washed out with 3 L of normal saline. Surgeons were instructed to repair the labrum in both groups if it was mechanically unstable once probed, showing visible displacement or chondrolabral separation. The primary outcome was patient-reported pain (using the 100-point visual analog scale [VAS]) at 12 months. Secondary outcomes included hip function (Hip Outcome Score [HOS] and International Hip Outcome Tool), physical and mental health (12-Item Short Form Health Survey), and health utility (EuroQol-5 Dimensions) at 12 months as well as any reoperations and other hip-related adverse events at 24 months. RESULTS: At 12 months, there was no difference in pain (VAS) between the groups (mean difference [MD], 0.11 [95% CI, -7.22 to 7.45]; P = .98). Also, 88.3% (189/214) of participants had a labral tear, of which 60.3% were repaired. For the secondary outcomes, there were no significant differences between treatment groups, with the exception of the HOS activities of daily living domain in which lavage showed significant improvement compared with osteochondroplasty (MD, -5.03 [95% CI, -10.40 to -0.03]; P = .049). By 24 months, there were significantly fewer reoperations reported in the osteochondroplasty group (8/105) than the lavage group (19/104) (odds ratio, 0.37 [95% CI, 0.15-0.89]; P = .026). The primary reasons for a reoperation included hip pain (15/27; 55.6%) and a reinjury of the labrum (11/27; 40.7%). CONCLUSION: Both the osteochondroplasty and the lavage groups with or without labral repair for FAI had significantly improved pain or function significantly at 1 year. By 2 years, the reoperation rate was significantly lower in the osteochondroplasty group. REGISTRATION: NCT01623843 (ClinicalTrials.gov identifier).

Clinical Outcomes and Midterm Survivorship of an Uncemented Primary Total Hip Arthroplasty System.

BACKGROUND: The rise in total hip arthroplasty (THA) has led to a concomitant increase in revision THAs. Tracking implant performance therefore remains a significant element of scientific inquiry to garner and maintain public trust in this procedure. There are few available reports of outcomes of a single manufacturer's total hip system outside registry data. METHODS: We performed a retrospective review of a prospectively generated database to evaluate outcomes of a single manufacturer's femoral stem and acetabular shell for THA. We report the functional outcomes, revision data, and survivorship for this total hip system. RESULTS: A total of 1942 primary THAs were implanted into 1672 patients. There were of 57 revisions. There were no cases of acetabular failure at 10-year follow-up. All functional outcome scores demonstrated significant improvements following THA. Kaplan-Meier survival analysis for all-cause revisions demonstrated 2-year implant survival of 97.6% (95% confidence interval [CI], 96.9-98.3), 5-year implant survival of 97.3% (95% CI, 96.5-98.1), and 10-year implant survival of 97.0% (95% CI, 96.0-98.0). When infection was excluded, implant survivorship improved to 99.2% (95% CI, 98.8-99.6) at 2 years, 98.9% (95% CI, 98.5-99.4) at 5 years, and 98.7% (95% CI, 98.1-99.4) at 10 years. CONCLUSION: This THA implant system comprising an uncemented press-fit acetabulum used alongside a triple-tapered femoral stem is an excellent option for THA. Implant survivorship at 2, 5, and 10 years is among the best reported for any total hip system in the world.

Indications, Survivorship, and Clinical Outcomes of a Rotating Hinge Total Knee and Distal Femoral Arthroplasty System.

BACKGROUND: Rotating hinge knee prostheses (with or without distal femoral replacement) are indicated in cases of unreconstructible bony or soft tissue compromise. Despite their versatility, these implants have demonstrated high rates of mechanical failure. We aimed to review clinical outcomes of a novel hinged knee arthroplasty system. METHODS: We reviewed all cases in a prospective database of hinged total knee arthroplasty (with and without distal femoral arthroplasty) involving a single manufacturer's implant system at a large tertiary-level academic health sciences center. We collected reasons for surgery, implant survivorship, reasons for revision, and clinical outcomes (Short Form 12, Western Ontario and McMaster Universities Osteoarthritis Index, and Knee Society Scores). RESULTS: Seventy-six cases of hinged knee implants using the knee system under investigation were performed (39 hinged total knee and 37 distal femoral replacements) between 2011 and 2018, inclusive. Indications for surgery varied, with second-stage reimplantation most common for rotating hinge and fracture most common for distal femoral arthroplasty. There were 6 revisions in the rotating hinge group (none for aseptic loosening) and 5 in the distal femoral arthroplasty group (1 for aseptic loosening). Average follow-up was 2.89 ± 2.09 years. Postoperative Short Form 12 (Physical Component), Western Ontario and McMaster Universities Osteoarthritis Index, and Knee Society Scores were 30.12 ± 10.17, 55.90 ± 21.51, and 115.62 ± 45.20, respectively. CONCLUSION: This novel hinged knee system is a highly durable option for complex and revision knee arthroplasty. Early failures tend to be secondary to infection. We observed only a single case of aseptic loosening. Although these early results are encouraging, ongoing follow-up is required to determine long-term prognosis in patients receiving this implant.

Minimum 15-Year Results of a Dual-Offset Uncemented Femoral Stem in Total Hip Arthroplasty.

BACKGROUND: The aim of the present study is to assess the long-term clinical and radiological outcomes of a proximal porous-coated, dual-offset, tapered titanium alloy uncemented stem at a minimum of 15 years of follow-up. METHODS: We reviewed 210 total hip arthroplasties (in 193 patients) performed between 1996 and 1999 and followed prospectively in our database who received the Synergy stem. We report a Kaplan-Meier survival analysis as well as the Harris Hip Score, the Western Ontario and McMaster University Arthritis Index, and the Short Form Health Survey-12 scores. Radiographs were evaluated for evidence of subsidence, osteolysis, osteointegration, or loosening. RESULTS: The average follow-up was 16 years (range, 15-17.7 years). Kaplan-Meier survival analysis with revision of stem for aseptic mechanical loosening (1 stem) as the end point revealed a cumulative survival rate of 99.5% at 16 years. The Harris Hip Score, the Western Ontario and McMaster University Arthritis Index, and the Short Form Health Survey-12 physical scores were all significantly improved (P < .001) from the preoperative period to latest follow-up. Minor osteolysis was observed proximally in 14 hips (6.6%) with no osteolysis distal to the porous coating. CONCLUSION: To our knowledge, this study represents the largest series reporting the longest clinical follow-up of this third-generation, dual-offset, proximal ingrowth, tapered cementless stem. The Synergy stem design has achieved excellent clinical outcomes, predictable osteointegration, and outstanding survivorship of 99.5% at a minimum of 15 years follow-up, representing the standard for femoral stems at our institution.

Morbid Obesity in Revision Total Knee Arthroplasty: A Significant Risk Factor for Re-Operation.

BACKGROUND: The purpose of this study is to compare surgical and clinical outcomes between matched groups of morbidly obese (body mass index [BMI] >40 kg/m2) and non-morbidly obese (BMI <40 kg/m2) patients undergoing first-time revision total knee arthroplasty with a minimum 5-year follow-up. METHODS: Two groups of 87 patients (BMI >40 or <40 kg/m2) were matched 1:1 based on age at the time of revision, gender, and diagnosis for revision (aseptic or septic causes). RESULTS: The morbidly obese group had a significantly greater incidence of re-operation (34.5% [30/87] vs 16.1% [14/87], P = .005) and re-revision (27.6% [24/87] vs 12.6% [11/87], P = .014) with a significantly lower 10-year survivorship for re-operation (P = .05) and subsequent revision (P = .014). In particular, the aseptic sub-group had a greater incidence of re-operation (29.9% [20/67] vs 13.4% [9/67], P = .021) and re-revision (26.9% [18/67] vs 11.9% [8/67], P = .029). The non-morbidly obese group demonstrated higher final Western Ontario and McMaster Universities Index scores (63.1 ± 19.5 vs 55.5 ± 22.5, P = .030) and a greater change between pre-operative and final KSS (45.6 ± 44.3 vs 39.7 ± 48.4, P = .040) and SF-12 Mental component (3.6 ± 10.8 vs -1.4 ± 10.3, P = .013). CONCLUSION: Morbidly obese patients undergoing revision total knee arthroplasty have a greater risk of re-operation and re-revision while experiencing lower clinical outcome scores compared to non-morbidly obese patients. These patients should be informed of the higher potential for re-operation and the possibility of poor results.

Radiostereometric Analysis Permits In Vivo Measurement of Very Small Levels of Wear in TKA.

BACKGROUND: Revision of TKA as a result of polyethylene wear is decreasing, but long-term wear performance of polyethylene is still a topic of interest to surgeons and device manufacturers seeking to improve longevity. Measuring wear of modern, wear-resistant implants has been described using radiostereometric analysis (RSA). Performing in vivo measurements would establish whether implant retrieval studies are representative of wear in well-performing knees. QUESTIONS/PURPOSES: For a single knee implant system, we sought to determine (1) the linear wear rate using RSA; (2) the association between demographic factors and wear rate; and (3) the association between limb alignment and wear rate. METHODS: A total of 49 patients with a minimum followup of 10 years (median, 12 years; range, 10-20 years) were retrospectively selected. During the examined period, 4082 TKAs were performed of which 2085 were the implant examined in this study. There were 71 of these patients who met the criteria including an available full-leg radiograph postoperatively, and 34 of these patients returned for examination along with 15 additional from a separate RSA study that also met the criteria. All patients received a posterior-stabilized, cobalt-chromium-on-conventional polyethylene total knee implant from a single implant system, which was the most commonly used at our institution at the time. Patients underwent standing RSA examinations from 0° to 120° of flexion at a single time point without the use of marker beads. Linear wear rates (including creep) were measured based on intersections between the femoral component and tibial insert models. Associations between wear and patient age at surgery, sex, height, weight, body mass index, tibial insert size, and limb alignment were examined. RESULTS: Using the maximum linear wear rate from any flexion angle, the lateral rate was 0.047 mm/year (interquartile range [IQR], 0.034-0.066 mm/year) and the medial rate was 0.052 mm/year (IQR, 0.040-0.069 mm/year). Using the median of the linear wear rates across all flexion angles, the lateral rate was 0.027 mm/year (IQR, 0.017-0.046 mm/year) and the medial rate was 0.038 mm/year (IQR, 0.022-0.054 mm/year). This rate for males was 0.049 mm/year medially (IQR, 0.042-0.077 mm/year) and 0.032 mm/year laterally (IQR, 0.026-0.059 mm/year), and for females was 0.027 mm/year medially (0.016-0.039 mm/year) and 0.020 mm/year laterally (IQR, 0.013-0.032 mm/year). The wear rate for males was greater medially (difference = 0.022 mm/year, p < 0.001) and laterally (difference = 0.012 mm/year, p = 0.008). There were associations between greater wear and increasing height (ρ = 0.48, p < 0.001 medially and ρ = 0.30, p = 0.04 laterally), decreasing body mass index (ρ = -0.31, p = 0.03 medially), and greater implant size (ρ = 0.34, p = 0.02 medially). Increasingly varus leg alignment was associated with greater medial wear (ρ = 0.33, p = 0.02). CONCLUSIONS: Greater wear rates were associated with demographic factors and leg alignment. Further RSA wear studies of other modern implant systems would provide complementary information to retrieval studies and valuable data on wear resistance. CLINICAL RELEVANCE: Good wear resistance was demonstrated by well-performing implants in patients at long-term followup with wear magnitudes in agreement with reported values from retrieval studies.

The use of point-of-care ultrasound to diagnose patent foramen ovale in elective hip and knee arthroplasty patients and its association with postoperative delirium.

PURPOSE: Hip and knee arthroplasty surgeries are associated with embolism of materials such as air, cement, and fat. Patent foramen ovale (PFO) is a common congenital cardiac condition that has been reported to lead to paradoxical embolism. This observational study aimed to investigate if the presence of a PFO was associated with an increased risk of postoperative delirium in patients undergoing primary elective hip or knee arthroplasties. METHOD: This was a prospective cohort study at a tertiary teaching hospital. We enrolled patients undergoing primary elective hip or knee arthroplasty who did not have any risk factors for embolism or delirium. Bedside transthoracic echocardiography (TTE) with a bubble study was performed on all patients to detect the presence of PFO. The primary outcome was postoperative delirium as assessed by the standardized Confusion Assessment Method. Secondary outcomes included the ease of performing a TTE bubble study in the perioperative setting, the quality of the TTE images, length of stay, major cardiovascular and neurologic complications, and effects of anesthetic or analgesic management techniques on delirium. RESULTS: Two hundred two patients completed the study. The median [interquartile range] duration of stay was 2 [2-3] days. Only 16 patients (8%) had a positive bubble study. Postoperative delirium was observed in only one patient. Major adverse events were not seen. The inter-rater reliability for the TTE image quality scores was fair (kappa statistic = 0.22). CONCLUSION: Given the very low incidence of PFO and postoperative delirium in this study, we could not form any conclusions regarding the impact of a PFO on important outcomes including delirium or other major adverse events. No recommendation can be made regarding screening for PFO in patients scheduled for lower extremity arthroplasty surgery. TRIAL REGISTRATION: ClinicalTrials.gov (NCT02400892). Registered 27 March 2015.