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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 2-stage revision THA, (2) determine the causative organisms for repeat 2-stage revision THA, and (3) characterize the results of failed 2-stage revisions and evaluate patient-reported outcome measures (PROMs). A retrospective chart review was completed for patients who underwent 2-stage revision THA for PJI. Prospective data were collected on each patient, including demographics, causative organisms, complications, and type of reoperation. The PROMs, including Harris Hip Score, 12-item Short-Form Health Survey, and Western Ontario and McMaster Universities Osteoarthritis Index scores were obtained prior to 2-stage revision THA surgery and annually as part of standard clinical and radiographic follow-up. A total of 328 patients who underwent a 2-stage revision THA for a PJI were included in the study (mean age 67 years [range, 28 to 90], mean body mass index of 30.6 [range, 15 to 57]). The overall infection-free survivorship for 2-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 2-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 methicillin-resistant Staphylococcus aureus and polymicrobial infections. All PROMs showed statistical improvement from preoperatively to the latest follow-up appointment. Two-stage revision THA is associated with a good success rate in the treatment of PJIs at mid-term to long-term follow-up. Polymicrobial and methicillin-resistant Staphylococcus aureus infections are poor prognostic factors, making the eradication of infection more difficult. The management of PJIs continues to be one of the most important orthopaedic challenges to treat. [ABSTRACT FROM AUTHOR]

The incidence of total joint arthroplasty is increasing, with added emphasis on shifting care toward outpatient surgery. This has demonstrated improvements in costs and care; however, safety must be prioritized. Published assessment tools highlight candidates for outpatient surgery; however, they often do not define patients who have a worse prognosis. Limited healthcare resources occasionally force patients to convert to outpatient surgery or risk cancellation, creating a dilemma for both patients and surgeons. We evaluated the short-term (90-day) outcomes of patients converted from planned inpatient admission to same-day discharge on day of surgery outpatients and sought to identify any groups at risk, who may not be appropriate for this conversion. We identified all patients undergoing planned inpatient total hip or knee arthroplasty at a tertiary academic medical center over a 2-year period. We included patients discharged the day of surgery for analysis, excluding revision procedures and those performed for fracture care. A manual chart review identified demographic factors and primary outcome measures; including reoperation, readmission, and emergency room visits within a 90-day postoperative period. We identified a total of 80 patients who converted from inpatient to outpatient surgery over a 2-year interval. Over the first 90 days postoperatively 4 (5%) patients were readmitted: 2 (2.5%) for medical complications and 2 (2.5%) for reoperation. There were 2 (2.5%) reoperations; one (1.25%) for manipulation under anesthesia, and one (1.25%) for periprosthetic joint infection. There were 5 (6.3%) wound complications; however, only one (1.25%) required surgical intervention. A total of 5 (6.3%) patients returned to an emergency department, leading to a single (1.25%) hospital readmission. Hospital and healthcare resources are occasionally limited to the extent that patients must convert to outpatient surgery or risk cancellation. At our institution, the same-day conversion of planned inpatient hip and knee arthroplasty patients to outpatient surgery was safe and did not increase short-term clinical outcomes or complications. [ABSTRACT FROM AUTHOR]

The aim of the study was to analyze the Canadian Cardiovascular Society (CCS) guidelines for routine postoperative troponin testing after elective total hip arthroplasty (THA) to reduce the mortality rate resulting from myocardial injury. The purpose of this study was to assess the prognostic relevance of implementing these guidelines to minimize cardiac events in patients undergoing elective THA. Patients who underwent THA surgery in 2020 were included in the study. The inclusion criteria were elective THA patients aged ≥45 years, while emergency, revision, and simultaneous bilateral THA surgeries were excluded. The patients were categorized into 4 groups based on the CCS guidelines. The study included 669 patients who had an average age of 67 years. There were 43 patients (6.4%), who experienced a rise in troponin levels ≥30 ng/L and developed myocardial injury after noncardiac surgery. Among these patients, 8 developed cardiac complications, and one experienced a serious cardiac event that resulted in death. Notably, there was a significant increase in the length of hospital stay for patients who received the postoperative screening protocol. The implementation of the CCS guidelines for routine postoperative troponin testing in elective THA surgery did not significantly decrease the rate of cardiac events or mortality. [ABSTRACT FROM AUTHOR]

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. 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. 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. 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. [ABSTRACT FROM AUTHOR]

Despite the growing popularity of cementless total knee arthroplasty (TKA) in younger patients, the outcomes are unclear in the elderly population. We aimed to compare the clinical outcomes and survivorship of cementless TKA between different age groups. Utilizing our prospectively collected institutional database, we retrospectively reviewed all patients undergoing primary cementless TKAs at a tertiary care institute. We identified 347 TKA, which were divided into 3 groups based on age at the time of surgery. Group A was ≤ 60 years, Group B was 60 to ≤ 70 years, and Group C was > 70 years. We compared clinical outcomes (Knee Society Clinical Rating System [KSCRS], Western Ontario and McMaster University Osteoarthritis Index [WOMAC], and Veterans Rand 12 Item Health Survey [VR-12]) and survivorship between the groups. At final follow-up, range of motion, KSCRS, WOMAC, and VR-12 physical score were comparable (P >.05). The VR-12 Mental score was higher in Group B and Group C than in Group A (P =.003). Compared to preoperative scores, the change in KSCRS, WOMAC, and VR-12 physical and mental scores was comparable at the final follow-up (P >.05). No patient underwent revision for aseptic loosening. There were no cases of revision surgery for aseptic loosening in our cohort of 347 cementless TKAs. Patients > 70 years of age undergoing cementless TKA can achieve clinical scores equivalent to those of younger patients at short term (2-year) follow-up. Longer-term survivorship is still required, but based on early data, cementless TKA can be a safe option for older patients. [ABSTRACT FROM AUTHOR]

Bicruciate-stabilized (BCS) total knee arthroplasty (TKA) designs attempt to approximate natural knee mechanics. Multiple surgical techniques, including gap balancing (GB) and measured resection (MR), have been developed to provide optimal implant positioning and soft-tissue balance. The goal of this study was to determine the effect of surgical technique on BCS TKA contact kinematics. Secondary goals included investigating the change of kinematics over time and comparing BCS TKA kinematics to a posterior-stabilized (PS) design. The study included the BCS-GB, BCS-MR, and PS-MR groups. The BCS-GB and BCS-MR groups underwent weight-bearing radiostereometric analysis for multiple knee flexion angles at 3 months and 1 year postoperatively, whereas the PS-MR group was imaged at 1 year postoperatively. The medial and lateral contact kinematics were determined from implant poses. There were no differences in BCS TKA kinematics between the GB and MR techniques. There were differences in the mid-flexion ranges when comparing the 3-month and 1-year kinematics of the BCS design; however, they were less than 1.5 mm. Differences existed between the kinematics of the BCS and PS designs at all flexion angles for the medial condyle (P <.0006) and at 0° of flexion on the lateral condyle (P <.0001). Contact kinematics for a BCS design were similar for both surgical techniques, suggesting both are appropriate for this design. Small, likely clinically insignificant differences were found between 3-month and 1-year kinematics. The BCS TKA kinematics differed from the PS design; however, it is unclear whether these differences improve clinical outcomes. [ABSTRACT FROM AUTHOR]

Extensively porous-coated cylindrical stems have demonstrated excellent results in revision total hip arthroplasties (THAs). However, most studies are midterm follow-ups and of modest cohort size. This study aimed to evaluate long-term outcomes of a large series of extensively porous-coated stems. From 1992 to 2003, 925 extensively porous-coated stems were utilized in revision THAs at a single institution. The mean age was 65 years, and 57% of patients were males. Harris hip scores were calculated, and clinical outcomes were assessed. Radiographic assessment for stem fixation was categorized as either in-grown, fibrous stable, or loose according to Engh criteria. Risk analysis used Cox proportional hazard method. The mean follow-up was 13 years. Mean Harris hip scores improved from 56 to 80 at the last follow-up (P <.001). Fifty-three femoral stems (5%) were rerevised: 26 for aseptic loosening, 11 for stem fractures, 8 for infection, 5 for periprosthetic femoral fractures, and 3 for dislocation. Cumulative incidence of aseptic femoral loosening and femoral rerevision for any reason were 3% and 6.4% at 20 years, respectively. Nine of eleven stem fractures occurred with 10.5-13.5 mm diameters (mean 6 years). Radiographic review of unrevized stems demonstrated 94% bone-ingrown. Demographics, femoral bone loss, stem diameter, and length were not predictors of femoral rerevision. In this large series of revision THAs using a single extensively porous-coated stem design, the cumulative incidence of rerevision for aseptic femoral loosening was 3% at 20 years. These data confirm the durability of this stem in femoral revision, providing a long-term benchmark for newer uncemented revision stems. Level IV, retrospective study. [ABSTRACT FROM AUTHOR]

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. 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. 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). 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. [ABSTRACT FROM AUTHOR]

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. 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). 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. 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. [ABSTRACT FROM AUTHOR]

Several studies have reported negative results after total knee arthroplasty (TKA) in obese patients. This study aims to analyze the minimum 2-year outcomes in patients who have a body mass index (BMI) > 35 undergoing cemented TKA using an all-polyethylene tibial component (APTC) at a minimum of 2 years of follow-up. We retrospectively studied 163 obese patients (192 TKAs) who underwent a primary cemented TKA using an APTC comparing the outcomes of 96 TKA patients who had a BMI > 35 to 39.9 (group A) with 96 patients who a TKA and a BMI ≥40 (group B). Median follow-up of groups A and B were 3.8 years and 3.5 years respectively (P =.02). Multiple regression analyses were performed to evaluate independent risk factors associated with complications. Kaplan–Meier survival curves were estimated, defining failure as the need for any further femoral or tibial revision surgery with implant removal, irrespective of the reason. There was no significant difference at the latest follow-up patient-reported outcomes between both groups. Survivorship, as defined by revision for any reason, was 99% for group A and 99% for group B (P = 1.00). There was 1 aseptic tibial failure in group A, and 1 septic failure in group B. Multiple regression analyses showed no significant associations between age (odds ratio [OR] = 1.00; P =.98; 95% confidence interval (CI) = 0.93 to 1.08), sex (OR = 1.38; P =.70; 95% CI = 0.26 to 7.25), BMI (OR = 1.00; P =.95; 95% CI = 0.87 to 1.16), and complication rate. At a median 3.7-year follow-up, the use of an APTC provided excellent outcomes and survivorship in patients who had Class 2 and Class 3 obesity. Level III, therapeutic study. [ABSTRACT FROM AUTHOR]

Contact kinematics in total knee arthroplasty (TKA) has been shown to affect tibial component migration. However, previous studies correlating kinematic variables to implant migration were completed with older TKA designs. The goal of this study was to determine if there are associations between contact kinematics and tibial component migration for a cemented, bicruciate stabilized (BCS) TKA system. A total of 54 knees implanted with a BCS TKA system were analyzed using radiostereometric analysis (RSA). Patients underwent RSA exams at 2 weeks, 6 weeks, 3 months, 6 months, 1 year, and 2 years post operation to measure tibial component migration. At 1 year, contact kinematics was evaluated during a quasi-static deep knee bend. Linear regression analyses were performed between kinematic variables and migration values. Significant correlations were found between contact kinematics and tibial component migration. Excursion on the lateral condyle was the most consistent variable correlating with implant migration. Six patients had > 0.2 mm migrations from 1 to 2 years post operation indicating continuously migrating tibial components, and most had atypical contact kinematics. Kinematics was shown to influence tibial component migration. Reduced lateral excursion, suggesting a more constrained lateral condyle, resulted in greater implant migration. The 6 patients who had continuously migrating tibial components had demographic factors that may limit the ability to endure unintended force transmissions caused by abnormal kinematics. These results highlight the importance of restoring knee kinematics with this BCS TKA design to minimize improper force transmissions and resultant increased implant migrations. [ABSTRACT FROM AUTHOR]

There has been a recent increase in the use of cementless fixation for primary total knee arthroplasty. While the early results of contemporary cementless implants are promising, understanding the behavior of cementless tibial baseplates under loading remains an ongoing interest. The objective of this study was to identify the pattern of displacement that occurred under loading for a single cementless tibial baseplate design at one year post operation for stable and continuously migrating implants. There were 28 subjects from a previous trial of a pegged highly porous cementless tibial baseplate evaluated. Subjects underwent supine radiostereometric exams from two weeks through one year after surgery. At one year, subjects also underwent a standing radiostereometric exam. Fictive points on the tibial baseplate model were used to relate translations to anatomical locations. Migration over time was calculated to determine if subjects displayed stable or continuous migration. The magnitude of inducible displacement between the supine and standing exams was calculated. Inducible displacement patterns were similar between stable and continuously migrating tibial baseplates. Displacements were greatest in the anterior-posterior axis followed by the lateral-medial axis. Correlation of displacements between adjacent fictive points in these axes indicated an axial rotation of the baseplate occurred under loading (r 2 = 0.689-0.977, P <.001). Less displacement occurred in the superior-inferior axis and correlations indicated an anterior-posterior tilt of the baseplate occurred under loading (r 2 = 0.178-0.226, P =.009-.023). From supine to standing position the predominant pattern of displacement for this cementless tibial baseplate was axial rotation, with some subjects also displaying an anterior-posterior tilt. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: Implant migration and altered kinematics have been thought to impact patient-reported outcome measures (PROMs) and postoperative patient satisfaction. In this study comparing satisfied and dissatisfied total knee arthroplasty (TKA) patients, we hypothesized that dissatisfied patients will have greater continuous implant migration and that there will be differences in joint kinematics, objective functional measurements, and PROMs between satisfied and dissatisfied patients.Methods: The Knee Society Score Satisfaction Subsection questions regarding satisfaction with function were used at least 6 months postoperation to split 50 patients into satisfied and dissatisfied groups. Patients underwent radiostereometric analysis to evaluate migration and kinematics. A wearable sensor system obtained objective measurements of patient function during timed up and go tests. PROMs were recorded preoperation and postoperation.Results: No statistically significant differences were found in migration between satisfied and dissatisfied groups. Statistical kinematic differences existed in lateral anteroposterior contact location at 20° and 40° of flexion at 1 year, where the dissatisfied group had more anteriorly located lateral contact. No statistically significant differences were present in objective functional measurements. Satisfied and dissatisfied groups had differing PROMs at 4 timepoints or greater for each questionnaire.Conclusions: No differences were found in tibial component migration or objectively measured function between satisfied and dissatisfied patients. Functionally dissatisfied patients had more anteriorly positioned contact on the lateral condyle in early flexion and reported more pain and unmet expectations. These findings suggest that improving the functional satisfaction of TKA requires restoration of kinematics in early flexion and management of patient's pain and expectations. [ABSTRACT FROM AUTHOR]

Background: The goal of this study is to investigate the migration and inducible displacement of a bicruciate-stabilized (BCS) total knee arthroplasty implanted using gap balancing (GB) or measured resection (MR) surgical techniques. We hypothesized equal migration and displacement between the techniques.Methods: The study is a single-blinded, prospective, randomized controlled trial, with allocation of 71 patients to either GB or MR groups. Fifteen patients were withdrawn, resulting in 31 patients in the GB group and 25 in the MR group. Patients received the JOURNEY II™ BCS implant. Migration and inducible displacement were evaluated using radiostereometric analysis and patient examinations were performed at a 2-week baseline, and at 6 weeks, 3 months, 6 months, 1 year, and 2 years postoperation.Results: No differences (P > .05) existed between GB and MR groups for any measurement of tibial or femoral migration. Both groups had tibial migrations below 0.5 mm from baseline to 6 months, and below 0.2 mm from both 6 months to 1 year and 1-2 years postoperation. No differences (P > .05) were found between GB and MR groups for inducible displacement.Conclusion: No differences were found in implant migration or inducible displacement between GB and MR groups. The BCS implant can be expected to have migration risks on par with industry standards and both surgical techniques are safe and effective options for implantation of this implant design. [ABSTRACT FROM AUTHOR]

Background: Patient-specific instrumentation (PSI) has been introduced in total knee arthroplasty (TKA) with the goal of increased accuracy of component positioning by custom fitting cutting guides to the patient's bony anatomy. A criticism of this technology is the associated cost. The purpose of this randomized controlled trial was to determine the cost-utility of PSI compared with standard of care (SOC) instrumentation for TKA in an obese population.Methods: Patients with body mass index greater than 30 with osteoarthritis and undergoing primary TKA were randomized to SOC or PSI. Patients completed a health care resource use diary and the EuroQol-5D at three, six, nine, and 12 months and the Western Ontario and McMaster Universities Osteoarthritis Index at three and 12 months postsurgery. We performed cost-utility and cost-effectiveness analyses from public health care payer and societal perspectives.Results: One hundred seventy-three patients were included in the analysis with 86 patients randomized to PSI and 87 to SOC. PSI was dominated (more costly and less effective) by SOC from a health care payer perspective. From a societal perspective, an incremental cost-utility ratio was calculated at $11,230.00 per quality-adjusted life year gained, which is cost-effective at a willingness to pay threshold of $50,000. Net benefit analyses found PSI was not significantly cost-effective at any willingness to pay value from either perspective.Conclusion: Our results suggest that widespread adoption of PSI may not be economically attractive or clinically indicated. Future considerations are to compare long-term clinical outcomes and radiographic alignment between the groups. [ABSTRACT FROM AUTHOR]

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. 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. 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. 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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Background: The management of the patella during total knee arthroplasty (TKA) remains controversial. The aim of this study is to evaluate the evidence regarding the use of patellar resurfacing in TKA.Methods: A meta-analysis of randomized controlled trials (RCTs) was performed to compare outcomes between knees receiving patellar resurfacing vs those not receiving resurfacing during primary TKA. Outcomes of interest were the Knee Society Scores, reoperation rates, anterior knee pain, patient satisfaction, Oxford Knee Score, Knee Injury and Osteoarthritis Outcome Score subscores, and range of motion.Results: Twenty RCTs met all eligibility criteria and were included in the analysis. There were statistically significant differences favoring the resurfaced group in the knee component and functional component of Knee Society Scores that were not clinically significant. There was an increased risk of reoperation among knees that did not receive resurfacing with number needed to treat to prevent one case of reoperation of 25 knees (for reoperation for any reason) and 33 knees (for reoperation for anterior knee pain). There were no statistically significant differences in any other outcomes.Conclusion: The only clear relationship is that knees that do not receive patellar resurfacing are more likely to receive reoperation, most often for secondary resurfacing. However, the disease burden of differing complication profiles associated with resurfacing and nonresurfacing groups remains unclear. Continuing to collect data from large, well-designed RCTs would be beneficial in guiding management of the patella during TKA. [ABSTRACT FROM AUTHOR]

Background: For a PCL-retaining (posterior cruciate ligament) total knee arthroplasty (TKA) to function suitably, proper soft tissue balancing, including PCL recession, is required. Yet, when the recession of the PCL is needed, there is still a debate as to whether a cruciate-retaining (CR) TKA should be converted to a posterior-stabilized TKA due to the concern of instability and poorer clinical outcomes. The purpose of this study is to determine whether recession of the PCL adversely affects clinical outcomes in patients who undergo CR TKA.Methods: CR TKAs of the same design performed by the senior author (J.M.) were identified between December 2006 and July 2015. Clinical outcome measurements were collected and included the Western Ontario and McMaster Universities Osteoarthritis Index score, the Knee Society Clinical Rating System, Short Form-12 Physical Composite Score/Mental Health Composite Score, and revision rates.Results: There were no significant differences in clinical outcome when the PCL was retained, partially recessed, or completely released during PCL-retaining TKA (Western Ontario and McMaster Universities Osteoarthritis Index: P = .54, Knee Society Clinical Rating System: P = .42, Short Form-12 Mental Health Composite Score: P = .89, Short Form-12 Physical Composite Score: P = .527).Conclusion: This study presents evidence of similar clinical outcomes when the PCL is retained or released during PCL-retaining TKA, provided attention is paid to appropriate soft tissue balancing. CR TKA undergoing partial or complete release of the PCL should not routinely be converted to a posterior-stabilized knee design.Level Of Evidence: Level II, Prognostic study. [ABSTRACT FROM AUTHOR]

Background: Minimal to extensive medial soft tissue releases are part of the exposure and achieving adequate varus knee balance in total knee arthroplasty (TKA). However, the effect of these releases on knee kinematics and patient-reported outcomes is unclear. Our objective was to compare the postoperative in vivo tibiofemoral contact kinematics of a posterior-stabilized TKA between patients who received minimal medial soft tissue releases intraoperatively to those who received extensive releases. We also compared these groups using patient-reported outcomes.Methods: A prospective imaging study was performed in a single-center over a 14-month period. Patients with end-stage osteoarthritis and varus deformity undergoing primary TKA were included. Baseline data were collected 1 month before surgery. The radiostereometric analysis imaging took place at least 1 year postoperatively and composed of weight-bearing radiographic stereo examinations of knee flexion starting in full extension and in 20° increments of flexion to a maximum of 120°. Intraoperative medial soft tissue releases were recorded. Patient-reported outcomes used included Short-Form 12, Western Ontario and McMaster Osteoarthritis Index, and Knee Society Score.Results: Fifty-one patients were included in the statistical analysis. Demographic characteristics were similar between all. Patients were divided into 3 groups depending on the amount of releases they received. No statistically significant differences in tibiofemoral contact positions or excursions on the medial or lateral condyles were found throughout flexion from 0° to 120°. Postoperative patient-reported outcome scores were not different.Conclusion: Correcting severe varus deformities with extensive medial soft tissue release largely did not alter knee kinematics or clinical outcome scores compared to those with minimal soft tissue release. [ABSTRACT FROM AUTHOR]

Background: Periprosthetic femur fractures around total hip (THA) and total knee (TKA) arthroplasties are difficult complications to manage. With native hip fractures, delay to fixation has been correlated with an increase in postoperative mortality. The effect of time to definitive fixation of periprosthetic femur fractures around THA and TKA is not well established. The aim of our study is to evaluate the effect of time to definitive fixation on postoperative length of stay and mortality for patients with periprosthetic femur fractures around THA and TKA.Methods: A review of 2537 arthroplasty patient charts yielded 235 patients who were diagnosed with a periprosthetic femur fracture at our institution from 2005 to 2014. Time to surgical management, length of stay, demographics, referral status, fracture classification, and fixation modality along with mortality was recorded for all patients.Results: One hundred eighty patients met study inclusion (111 THAs, 69 TKAs). Average age was 79.2 years and 72.2% were female. The average time from admission to definitive fixation was 96.5 hours with 31.1% of patients having surgery within 48 hours after presenting to hospital. Postoperative length of stay and mortality were not affected by time to definitive fixation greater than 48 hours for either of the periprosthetic TKA or THA patient cohorts. Postoperative mortality within 1 year was 5.5% for all patients (6.3% THA, 4.3% TKA).Conclusion: The timing of fixation of periprosthetic femur fractures does not appear to affect postoperative length of stay or mortality within 1 year. [ABSTRACT FROM AUTHOR]

Background: Contact kinematics between total knee arthroplasty components is thought to affect implant migration; however, the interaction between kinematics and tibial component migration has not been thoroughly examined in a modern implant system.Methods: A total of 24 knees from 23 patients undergoing total knee arthroplasty with a single radius, posterior stabilized implant were examined. Patients underwent radiostereometric analysis at 2 and 6 weeks, 3 and 6 months, and 1 and 2 years to measure migration of the tibial component in all planes. At 1 year, patients also had standing radiostereometric analysis examinations acquired in 0°, 20°, 40°, and 60° of flexion, and the location of contact and magnitude of any condylar liftoff was measured for each flexion angle. Regression analysis was performed between kinematic variables and migration at 1 year.Results: The average magnitude of maximum total point motion across all patients was 0.671 ± 0.270 mm at 1 year and 0.608 ± 0.359 mm at 2 years (P = .327). Four implants demonstrated continuous migration of >0.2 mm between the first and second year of implantation. There were correlations between the location of contact and tibial component anterior-posterior tilt, varus-valgus tilt, and anterior-posterior translation. The patients with continuous migration demonstrated atypical kinematics and condylar liftoff in some instances.Conclusion: Kinematics can influence tibial component migration, likely through alterations of force transmission. Abnormal kinematics may play a role in long-term implant loosening. [ABSTRACT FROM AUTHOR]

Background: Trunnionosis at the modular head-neck taper interface in metal-on-polyethylene total hip arthroplasty (MoP THA) has been shown to occur, and represents a potential mode of MoP THA failure. The purpose of the present investigation is to elucidate differences in fretting and corrosion at the head-neck taper interface of prostheses retrieved from bipolar hemiarthroplasty (BH) and MoP THA.Methods: A retrieval analysis of BH and MoP THA prostheses featuring a single taper design from a single manufacturer and in vivo for a minimum 2 years was performed. Fifteen femoral heads of 28-mm diameter and corresponding femoral stems retrieved from BH were compared with MoP THA implants matched based on time in vivo and head length (28 mm, -3 mm to 28 mm, +8 mm). Fretting and corrosion damage scoring was completed under stereomicroscopic visualization.Results: Femoral head bore tapers retrieved from BH exhibited decreased overall fretting (P = .02), when compared to those retrieved from MoP THA. Total corrosion scores for all retrieved implants were positively correlated with implantation time (ρ = 0.54, P < .02).Conclusion: Femoral heads retrieved from BH exhibit decreased fretting damage compared to those retrieved from MoP THA. The added articulation in BH implants may decrease torque produced at the head-neck taper junction, thereby decreasing fretting. Increased fretting damage in implants from MoP THA is not associated with increased corrosion in 28-mm heads of this taper design. The longer a BH or MoP THA prosthesis is implanted, the greater the risk of damage due to corrosion. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study is to measure acetabular cup position and wear of the highly crosslinked polyethylene liner in the supine and standing position for patients at a minimum of 10 years after the operation.Methods: A total of 38 patients were recruited at a mean of 12.5 years after the operation. All patients received a single acetabular cup design with a highly crosslinked liner and a 28-mm cobalt-chromium femoral head. Patients underwent supine and standing radiostereometric examinations in which the X-ray sources and detectors were positioned to obtain an anterior-posterior and cross-table lateral radiograph. Acetabular cup position and the three-dimensional wear rate were measured from the radiographs, and outcome scores were recorded for each patient.Results: Anteversion significantly increased (P < .0001) a mean of 12° from supine (15.1° ± 10.4°) to standing (27.2° ± 10.5°) position. Inclination also significantly increased (P = .001) a mean of 2° from supine (44.4° ± 6.8°) to standing (46.3° ± 7.7°) position. There was no difference (P = .093) in wear rate between supine (0.067 ± 0.070 mm/y) and standing (0.073 ± 0.074 mm/y) positions. There were no correlations between cup orientation and wear rate in either position.Conclusion: Highly crosslinked polyethylene is a forgiving bearing material. Although adherence to the traditional acetabular position target zone is recommended, ensuring hip stability and consideration of the patient's functional position are also important objectives to consider for the acetabular position. [ABSTRACT FROM AUTHOR]

Introduction: Trochlear design plays a role in patellofemoral kinematics. Little is known regarding differences in the contact properties between modern designs. The purpose of the present study was to analyze patellofemoral joint contact by identifying areas of joint surface damage and wear in retrieved femoral components of 3 modern designs.Materials: Eighteen retrieved femoral components featuring 3 different modern designs (Triathlon, SIGMA, and GENESIS II) were matched based on time-in-vivo, age, gender, and body mass index. Trochlear wear and surface damage were assessed using visual inspection, light microscopy, and light profilometry.Results: Visual inspection of the femoral components showed evidence of surface damage in all implant types. No significant differences between the groups were found with respect to surface damage and wear on visual inspection. Light profilometry of retrieved components showed that retrieved Triathlon (P = .002) and SIGMA (P = .009) components were significantly rougher than the corresponding reference components. The GENESIS II retrieved components were not substantially rougher than the reference components (P = .48). Light profilometry analysis showed significantly increased roughness of retrieved SIGMA components compared with Triathlon or GENESIS II components, particularly in the proximal trochlear groove and the medial trochlea.Conclusion: As the volume and patient demands for total knee arthroplasty increase, a greater understanding of the patellofemoral joint is warranted. Patellofemoral kinematics can have an effect on the surface characteristics of total knee arthroplasty components. Retrieved SIGMA components appeared to have increased roughness compared with Triathlon or GENESIS II components. The etiology and long-term effects of increased trochlear roughness require further investigation. [ABSTRACT FROM AUTHOR]

Background: Although it has been shown that morbidly obese patients experience good outcomes following primary total hip arthroplasty (THA), it is unclear whether this also applies to revision surgery. The purpose of this study was to examine the effect of a high body mass index (BMI) on the outcome of revision THA.Methods: We identified 56 patients with a BMI >40 kg/m2 who had undergone revision THA between 1994 and 2009 at our hospital (group B). Mean age, BMI, and follow-up were 66.4 years, 45.7 kg/m2, and 11.7 years, respectively. This was matched with a second group of patients with a BMI between 30 and 40 kg/m2 according to age, gender, and date of index procedure (group A). Mean age, BMI, and follow-up were 66.6 years, 33.6 kg/m2, and 12 years, respectively. Outcome measures included the rate of subsequent revision, implant survival, and the Harris hip score (HHS).Results: Patients with a BMI >40 kg/m2 had a significantly increased risk of revision surgery (27% vs 12%, P = .036). Cumulative implant survival was 85% (95% CI, 69-92) in group A and 69% (95% CI, 54-80) in group B at 15 years. HHS increased significantly following surgery in both groups (group A: 26.3-79.3) and (group B: 37.6-69.9; P < .001). However, HHS at last follow-up was significantly higher in group A (79.3 vs 69.9, P = .042).Conclusion: Morbid obesity appears to be associated with an increased risk of failure and lower functional scores following revision THA. Patients should be well informed of this before surgery. [ABSTRACT FROM AUTHOR]

Background: Several treatment modalities exist for the treatment of perioperative anemia. We determined the effect of oral iron supplementation on preoperative anemia, and the use of blood-conserving interventions before total hip arthroplasty (THA) and total knee arthroplasty (TKA).Methods: A total of 3435 total joint arthroplasties (1461 THAs and 1974 TKAs) were analyzed during 2 phases of a blood conservation program. The first phase used erythropoietin alfa (EPO) or intravenous (IV) iron for patients at risk for perioperative anemia. The second phase included these interventions, as well as preoperative iron supplementation. The effect on preoperative hemoglobin (Hb) and serum ferritin, as well as EPO and IV iron utilization, was determined.Results: Oral iron therapy increased preoperative Hb level by 6 g/L (P < .001) and 7 g/L (P < .001) in the hip and knee cohorts, respectively. Serum ferritin level rose by 80 μg/L (P < .001) and 52 μg/L (P < .001) in the hip and knee cohorts, respectively. The number of patients with an Hb level <130 g/L was significantly reduced (P < .001 for both cohorts), as were patients with serum ferritin levels <35 μg/L (P = .002 for hip and P < .001 for knee cohorts). Utilization of EPO reduced from 16% to 6% (P < .001) and 18% to 6% (P < .001) in the hip and knee cohorts, respectively. Utilization of IV iron reduced from 4% to 2% (P = .05) and 5% to 2% (P < .001) in the hip and knee cohorts, respectively.Conclusion: Oral iron therapy reduced the burden of perioperative anemia and reduced utilization of other blood-conserving therapies before THA and TKA. Future research should delineate the cost-effectiveness of oral iron therapy. [ABSTRACT FROM AUTHOR]

Background: There are various possible methods of skin closure in total hip arthroplasty (THA) through a lateral skin incision. The cost and time required for each can vary between techniques. The objective of this study was to determine whether there is a difference in patient and surgeon rating of scar outcome using a combination of subcuticular suture and skin adhesive (subcuticular MONOCRYL and DERMABOND [SMD]) vs staples for skin closure after THA.Methods: Patients undergoing THA were recruited from a university hospital. Patients were randomized to staples or SMD. Patient and Observer Scar Assessment Scale data were collected postoperatively. In addition, visual analog scale pain scores, wound drainage, length of stay, time to closure, and total cost were collected.Results: One hundred twenty-nine patients were available for final analysis. There was no significant difference in Patient and Observer Scar Assessment Scale scores at 6 weeks or 3 months (P = .71). There was no difference in visual analog scale pain scores (P = .64, P = .49). The staple group had a higher rate of discharge on postoperative days 1 and 3 (P < .001, P < .001) but had a 1.6-minute shorter time of closure (P < .001). There was no significant difference in length of stay or total cost (P = .5).Conclusion: Although there are some small initial advantages to each method of skin closure, there is little difference in scar outcome when comparing SMD and staples. [ABSTRACT FROM AUTHOR]

Background: Trunnion tribocorrosion in total hip arthroplasties is concerning, but retrieval studies often are subjective or lack comparison groups. Quantitative comparisons of clinically relevant implants are required. The purpose of this investigation was to evaluate material loss in metal-on-metal (MoM) and metal-on-polyethylene (MoP) total hip articulations while controlling for trunnion design and head size.Methods: The 166 retrieved femoral heads from 2 manufacturers were analyzed. Four cohorts based on head size, trunnion design, manufacturer, and articulation type (MoM vs MoP) were created. Corrosion was measured by a coordinate measurement machine, and material loss was assessed (MATLAB).Results: Retrieved femoral heads from MoP articulations had 5 times less trunnion material loss than MoM articulations, on average, for both manufacturers. There was no difference in material loss between large modular head (>40 mm) and 36-mm MoM hip trunnion. Implants with a material loss above the detectable limit demonstrated a correlation with time in vivo only in MoP articulations.Conclusion: Retrieved femoral heads from MoP bearing couples had a lower magnitude of material loss than MoM couples, independent of head diameter. A time in vivo effect was only seen in MoP bearings. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to examine the 15-year survivorship and long-term clinical outcomes of the GENESIS II total knee arthroplasty (TKA).Methods: Patients who underwent TKA with the GENESIS II system between 1995 and 1999 were retrieved from our institutional database. We report a Kaplan-Meier survival analysis as well as Western Ontario and McMaster Universities Arthritis Index, the Short Form Health Survey-12 (SF-12), and the Knee Society Scores at a mean of 16 years.Results: Four-hundred sixty-nine TKAs were performed with a mean patient age of 68 years. Patients were followed up prospectively for a mean of 16 years (range, 14.8-19.5 years). The Kaplan-Meier survival analysis at 15 years, with revision for any reason as the end point, was 96.4% (95.5%-97.3%). The Western Ontario and McMaster Universities Arthritis Index and the Knee Society Scores were significantly improved (P < .001) from the preoperative period to the latest follow-up. Patients had a significant improvement (P < .001) from the preoperative to the latest follow-up on the Physical Health Composite Score of the SF-12, but no change was noted on the Mental Health Composite Score of the SF-12.Conclusion: The unique design features of the GENESIS II TKA system have remained a constant over the duration of its clinical use, a rarity for contemporary TKA systems which are often altered before the publication of long-term results. The GENESIS II continues to demonstrate excellent long-term survivorship and improvements in health-related outcomes at a mean of 15 years, representing the standard for TKA systems at our institution. [ABSTRACT FROM AUTHOR]

Background: Coronal plane alignment is one of the contributing factors to polyethylene wear in total knee arthroplasty.Methods: Based on 95 retrieved polyethylene inserts, wear and damage patterns were analyzed in relationship to the overall mechanical alignment and to the position of the tibial component.Results: A progression of wear was observed with progressively mechanical varus alignment. However, there was significantly more damage in the lateral compartment in the mild and moderate varus group compared to the valgus group. No difference in damage was seen between all groups for tibial component positioning in valgus or varus.Conclusion: Progressive wear was observed with progressively varus alignment with more damage at the lateral side. This observation is unique and might be explained by lateral condylar lift-off inducing impact and shear loading in the varus group. [ABSTRACT FROM AUTHOR]

Background: Measured resection (MR) and gap balancing (GB) are common surgical techniques for total knee arthroplasty (TKA). Controversy has arisen as each conceptually differs in how the knee is balanced through bone and soft tissue management. The objective of the present study was to compare both the frequency of condylar liftoff and the location of femorotibial contact from extension through midflexion between patients undergoing GB or MR TKA.Methods: A total of 24 knees (23 patients) were randomly assigned at referral to either a surgeon performing MR or GB TKA with the same single radius, posterior-stabilized implant (12 per cohort). At 1-year postoperation, patients underwent biplanar radiographic imaging at 0°, 20°, 40°, and 60° of flexion. Condylar liftoff, contact location, and magnitude of excursion on each condyle were measured. Preoperative and postoperative clinical outcome scores were also collected.Results: There was no difference (P = .41) in the frequency of liftoff between cohorts. The MR cohort had more posterior contact on the medial condyle (P < .01) and more anterior contact on the lateral condyle (P < .01) throughout flexion. Motion patterns were similar between cohorts, with similar medial (P = .48) and lateral (P = .44) excursion, which was equal in magnitude between condyles for both MR (P = .48) and GB (P = .73). There was no difference in clinical outcome scores between groups.Conclusion: For this particular implant system, GB and MR appear to produce similar kinematic and patient-reported outcome results. [ABSTRACT FROM AUTHOR]

Background: Studies that have previously examined the relationship between acetabular component inclination angle and polyethylene wear have shown increased wear of conventional polyethylene with high inclination angles. To date, there are no long-term in vivo studies examining the correlation between cup position and polyethylene wear with highly crosslinked polyethylene.Methods: An institutional arthroplasty database was used to identify patients who had metal-on-highly crosslinked polyethylene primary total hip arthroplasty using the same component design with a minimum follow-up of 10 years. A modified radiostereometric analysis examination setup was utilized, recreating standard anteroposterior and cross-table lateral examinations in a single stereo radiostereometric analysis acquisition. The same radiographs were used to measure inclination angle and anteversion.Results: A total of 43 hips were included for analysis in this study. Average follow-up was 12.3 ± 1.2 years. The average linear wear rate was calculated to be 0.066 ± 0.066 mm/y. Inclination angle was not correlated with polyethylene wear rate (P = .82). Anteversion was also not correlated with polyethylene wear rate (P = .11).Conclusion: At long-term follow-up of >10 years, highly crosslinked polyethylene has a very low wear rate. This excellent tribology is independent of acetabular position. The low wear rate highlights the excellent results of metal on highly crosslinked polyethylene, and supports its use in total hip arthroplasty. [ABSTRACT FROM AUTHOR]

Background: Acetabular component positioning is crucial to a successful total hip arthroplasty (THA). This study evaluated the effect of absolute acetabular component position as well as acetabular position relative to bony anatomy on patient-reported functional outcomes after primary THA.Methods: Primary, press fit, hemispherical metal-on-polyethylene THA performed between 2003 and 2011 were analyzed. Western Ontario and McMaster Osteoarthritis Index (WOMAC), Harris Hip Score (HHS), Short Form-12 scores, and radiographs between 2 and 3 years after the index procedure were assessed.Results: Of the 1241 primary THA included, the mean abduction and anteversion angles were 44.4 ± 6.94 and 21.7 ± 11.9 degrees, respectively. The mean anterior and lateral overhang were 1.9 ± 3.6 and 2.5 ± 3.4 mm, respectively. There was no correlation between functional outcomes and acetabular inclination. A weak positive correlation between anteversion and HHS (P < .001) and WOMAC (P = .02) scores was found. For relative position, anterior overhang of the acetabular component beyond the bone resulted in inferior Short Form-12 physical function (P = .001), HHS (P = .004), and WOMAC (P < .001) scores compared to those with bony coverage. Mean HHS pain score was 41.20 ± 5.69 in patients with lateral overhang and 41.97 ± 5.04 in those who had bony coverage of the lateral edge of the acetabular component (P = .02).Conclusion: The tribology and biomechanics of acetabular component position have been extensively studied without examination of how it affects patient function. Although statistical significance was seen, clinical outcome scores were not sensitive enough to show a clinically significant effect of the absolute or relative position of the acetabular component. [ABSTRACT FROM AUTHOR]

Background: Fracture location is an important consideration in managing supracondylar periprosthetic femur fractures. The outcomes of locked plating and intramedullary (IM) nail fixation were therefore compared based on fracture location, being above or at/below the total knee arthroplasty (TKA) flange.Methods: Fifty-seven patients were identified from surgical records as being treated for supracondylar periprosthetic femur fracture with either a locking plate (n = 38) or IM nail (n = 19). Based on fracture location, either above or at/below the TKA flange, both groups were assessed for time to full weight bearing, time to radiographic union, number of postoperative complications, subsequent surgery, transfusion requirements, as well as range of motion, pain, and instability at most recent follow-up. Radiographs were reviewed to assess fracture alignment with comparisons made immediately postoperative to most recent.Results: Mean follow-up for IM nail and locking plate fixation was 13.9 and 15.6 months, respectively. There was no statistical difference between groups in the mean time to fully weight bear, the incidence of postoperative pain, range of motion, use of gait aids, time to full radiographic union, or the overall radiographic alignment of a healed fracture (P > .05). Comparison based on fracture location yielded similar outcomes. Nonunion was only demonstrated in the IM nail cohort, particularly for fractures below the TKA flange (n = 2).Conclusion: The use of either IM nail or locking plate fixation for supracondylar periprosthetic fractures provides comparable clinical outcomes. Caution is recommended in using IM nails for fractures below the flange where limited fixation may increase the risk of nonunion. [ABSTRACT FROM AUTHOR]

Background: The purpose of this study was to determine the gap achieved to the medial and lateral compartments following sectioning and release of the relevant soft tissues in preparation for a total knee arthroplasty.Methods: A custom-designed knee tensioner allowed the application of forces to the medial and lateral compartments of 12 cadaveric knee specimens. Loads of 100 N and 200 N were applied to each compartment, and the resulting displacement was measured in the following conditions: (1) All soft tissues intact, (2) an arthrotomy, (3) anterior cruciate ligament (ACL) sectioned, (4) posterior cruciate ligament (PCL) sectioned, and (5) release of the anterior aspect of the deep medial collateral ligament (MCL) fibers. Tensions were applied for all conditions from 90° to 0° of knee flexion in 30° increments.Results: No differences were found in medial or lateral displacement after the arthrotomy or releasing the ACL or PCL at either 100 N or 200 N. At the 100 N load application, there was a significant increase in gap width when the anterior portion of the deep MCL was released (7.49 mm) compared to the intact (5.28 mm) and arthrotomy (5.75 mm) conditions. With respect to the 200 N load application, there were statistically significant differences detected between the deep MCL fiber release (11.09 mm) and intact conditions (8.05 mm) and release of the deep MCL and arthrotomy conditions (8.77 mm).Conclusion: The medial parapetellar arthrotomy, ACL and PCL sectioning did not result in medial or lateral displacement changes. The release of the anterior fibers of the deep MCL as part of the surgical exposure increased the medial gap magnitude. [ABSTRACT FROM AUTHOR]

Background: Multiple periprosthetic joint infections (MPJIs) are uncommon. We determine the prevalence of developing a second-site periprosthetic joint infection.Methods: Our institutional arthroplasty database was reviewed. Those who developed a second-site infection had a retrospective chart review to determine the pathogen, timing of infection, comorbidities, and results of treatment.Results: Thirteen of 206 (6.3%) patients at-risk for MPJI experienced a second periprosthetic joint infection. Mode of the second infection was hematogenous in 6, all of whom were being treated for the index periprosthetic joint infection. Seven secondary infections did not relate to the index infection. Two patients were lost to follow-up, 5 continued on suppressive antibiotics, and 6 successfully cleared infection.Conclusion: The prevalence of MPJI has decreased compared with previous reports. [ABSTRACT FROM AUTHOR]

Background: Wear and tribocorrosion at the modular head-neck taper interface may be a cause of failure in metal-on-polyethylene total hip arthroplasty (THA). The present investigation endeavored to elucidate the effect of femoral head diameter on fretting and corrosion in retrieved head-neck tapers.Methods: A retrieval analysis of THA prostheses in vivo for a minimum of 1 year was performed. Twenty-three femoral heads of 32-mm diameter were matched with 28-mm heads based on time in vivo and head length (-3 mm to +8 mm). All included implants featured a single taper design from a single manufacturer. Fretting and corrosion damage scoring was performed for each implant under stereomicroscopic visualization.Results: Head diameter was observed to affect fretting (P = .01), with 32-mm femoral heads exhibiting greater total fretting scores than 28-mm heads. Fretting damage was greatest (P = .01) in the central concentric zone of the femoral head bore tapers, regardless of head diameter, length, or stem offset. No significant effect on total corrosion scores was observed for any head or stem variable. Retrieved implant total corrosion scores were positively correlated (ρ = 0.51, P < .001) with implantation time.Conclusion: Increased femoral head diameter in THA may produce greater fretting damage owing to and increased head-neck moment arm. There is no associated increase in corrosion with 28-mm and 32-mm heads of this taper design. The longer a THA prosthesis is implanted, the greater the risk of damage due to corrosion. [ABSTRACT FROM AUTHOR]

Background: This matched-cohort study aims to compare tribocorrosion between matched ceramic and cobalt-chromium femoral head trunnions and between matched Oxinium and cobalt-chromium femoral head trunnions. Secondary objectives were to investigate whether taper design, depth of trunnion, implantation time, age, body mass index, and gender have an effect on fretting and corrosion.Methods: All hip prostheses retrieved between 1999 and 2015 at one center were reviewed, giving a total of 52 ceramic heads. These were matched to a cobalt-chromium cohort according to taper design, head size, neck length, and implantation time. The trunnions were examined by 2 observers using a 4-point scoring technique and scored in 3 zones: apex, middle, and base. The observers were blinded to clinical and manufacturing data where possible. A separate matched-cohort analysis was performed between 8 Oxinium heads and 8 cobalt-chromium heads, which were similarly scored.Results: Ceramic head trunnions demonstrated a lower median fretting and corrosion score at the base zone (P < .001), middle zone (P < .001), and in the combined score (P < .001). Taper design had a significant effect on fretting and corrosion in the apex zone (P = .04) of the ceramic group, as well as the cobalt-chromium group (P = .03). Between Oxinium heads and cobalt-chromium heads, there was no significant difference in the fretting and corrosion score across all 3 zones (base: P = .22; middle: P = .92; and apex: P = .71) and for the combined score (P = .67).Conclusion: This study shows that ceramic head confers an advantage in trunnion fretting and corrosion. Taper design and implantation time were also significant factors for fretting and corrosion. [ABSTRACT FROM AUTHOR]

Background: Few studies had examined whether specific patient variables or performance on functional testing can predict length of stay (LOS) after total hip arthroplasty (THA). Such tools would enable providers to minimize prolonged LOS by planning appropriate discharge dispositions preoperatively.Methods: We prospectively recruited 120 patients undergoing a THA through an anterior (n = 40), posterior (n = 40), or lateral (n = 40) approach. Patients performed a timed up-and-go (TUG) test preoperatively to determine if it was predictive of hospital LOS after THA. Other variables of interest included patient age, body mass index, age-adjusted Charlson Comorbidity Index, mean procedure time, and time spent in the postanesthetic care unit. A logistic regression analysis was performed to determine which variables predicted LOS greater than 48 hours, which is our institution's target time to discharge.Results: The TUG test was predictive of LOS beyond 48 hours. For every 5-second interval increase in TUG time, patients were twice as likely to stay in hospital beyond 48 hours (odds ratio [OR] = 2.02, 95% confidence interval [CI] = 1.02-4.01, P = .043). Patient age (OR = 0.97, 95% CI = 0.90-1.05, P = .46), body mass index (OR = 1.01, 95% CI = 0.86-1.18, P = .90), Charlson Comorbidity Index (OR = 1.29, 95% CI = 0.68-2.44, P = .44), mean procedure time (OR = 1.05, 95% CI = 0.97-1.14, P = .27), and mean time in the postanesthetic care unit (OR = 1.00, 95% CI = 0.99-1.00, P = .94) were not predictive of increased LOS.Conclusion: The TUG test was predictive of hospital LOS after THA. It is a simple functional test that can be used to assist with discharge planning preoperatively to minimize extended hospital stays. [ABSTRACT FROM AUTHOR]

This study investigated whether subluxation of articulating antibiotic spacers is associated with the bone defects found and constraint required when re-implanting the knee arthroplasty components. Staged revisions for infections of primary total knee arthroplasties between 2004 and 2012 were examined. Radiographic sagittal and coronal subluxations of 72 knees were measured prior to second stage revision. Coronal subluxation was found to be associated with increased requirement for constrained knee systems (P<0.035). Sagittal subluxation was associated with greater tibia bone defects (P<0.037). Careful surgical technique and monitoring of articulating spacers should be done to avoid subluxation after stage 1 revision. If subluxation of the articulating spacer is present, constrained revision knee systems as well as augments should be available at time of re-implantation. [ABSTRACT FROM AUTHOR]

The purposes of this study were to determine the impact of surgical approach on costs of total hip arthroplasty (THA) from a hospital perspective and to provide an updated cost estimation of THA. A prospective, microcosting analysis was performed on 118 patients undergoing a THA through an anterior, lateral, or posterior approach. We determined that overall costs (intraoperative costs and hospital stay) were significantly less for the anterior ($7300.22; 95% confidence interval [CI], 7064.49-7535.95) vs lateral ($7853.10; 95% CI, 7577.29-8128.91; P = .031) and anterior vs posterior approach ($8287.46; 95% CI, 7906.42-8668.51; P < .001). A reduction in hospital length of stay when THA was performed through an anterior approach contributed significantly to an overall reduction in costs from a hospital perspective. [ABSTRACT FROM AUTHOR]

This study compared the damage scores and damage patterns in 19 tibial inserts from rotating hinge (RH) implants with 19 inserts from highly constrained (HC) implants. Each insert was divided into 16 damage zones and each zone was subjectively graded from a scale of 0-3 for seven different damage modes. The overall damage scores were comparable for the two groups (RH: 64.1 ± 15.4; HC: 66.1 ± 29.0; P = 0.59). The HC group, however, had greater post damage (compared to the post-hole of RH) while the RH group had greater backside damage. The pattern of damage was also different, with burnishing and cold flow being more common in HC group while pitting, scratching and embedded debris were more common in the RH group. [ABSTRACT FROM AUTHOR]

Current discussion exists whether to position a total knee arthroplasty (TKA) in slight undercorrection in varus osteoarthritis. The goal of this study was to analyse the effect of wear and lateral lift-off in primary TKA on coronal plane alignment and the implication to future constrained revision TKA. Seventy-six retrieved tibial inserts were analysed for the ratio of wear (RW), lateral lift-off and implications for future constrained revision surgery according to the coronal plane alignment. The RW significantly affects the coronal plane alignment in TKA. Progressive wear and lateral lift-off were seen with progressive varus alignment. However, there was no difference in constrained revision between mild varus and moderate varus aligned TKAs. [ABSTRACT FROM AUTHOR]

This study examines how taper design affects corrosion and fretting at the head trunnion surface. All hip prostheses retrieved between 1999 and 2013 with 28 mm/+ 0 heads were selected, resulting in 44 cobalt-chrome-on-polyethylene implants, representing six taper designs. Mean implantation time: 8.9 ± 3.7 years. The femoral head tapers were scored for fretting and corrosion using the Goldberg scale as both a combined score and by three zones (apex, central and base). There was no difference in age ( P = 0.34), BMI ( P = 0.29), or implantation time ( P = 0.19) between taper groups. The 11/13 taper had the highest combined corrosion and fretting score, but no difference ( P = 0.22) between groups for combined scores ( P = 0.22 for corrosion, P = 0.19 for fretting). In a zone-specific analysis, the 11/13 taper had highest corrosion score at base zone ( P = 0.02). Taper design had a significant effect on corrosion at base of trunnion. [ABSTRACT FROM AUTHOR]

327 proximal and 185 extensively coated femoral stems with mean 10-year follow-up were reviewed. Implant survivorship, clinical outcomes, and radiographic analyses were compared. Kaplan–Meier implant survivorship was 97.5% for the proximal, and 98.8% for the extensively coated stem for stem-only revisions at 10-years. The proximally coated stem outperformed on the PCS arm of the SF-12 ( P = 0.04) and stiffness arm of the WOMAC ( P = 0.03). Otherwise, all clinical outcomes were comparable. Thigh pain incidence was 12.5% and 5.3% for the extensive versus proximally coated groups, respectively ( P = 0.007). Radiographic review identified more severe stress shielding ( P < 0.001) in the extensively coated stems. This study supports the long-term clinical track record of total hip arthroplasty using two different cementless stem designs. [ABSTRACT FROM AUTHOR]