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Background: Metaphyseal cones are used to manage bone loss in revision total knee arthroplasty with increasing popularity. Post-operative radiographs and explant procedures suggest that cement may extrude around the cone implant into the cone-bone interface and prevent biologic in- or on-growth. The purpose of this study was to perform a retrieval analysis to describe the pattern of direct cementation onto the porous surface area of metaphyseal cones., Methods: Eighteen tibial and femoral cones were identified in an institutional implant retrieval registry. Anterior, posterior, medial and lateral quadrants were digitally mapped for direct cementation, bone ongrowth and fibrous ongrowth were calculated as a percentage of the porous surface area. Plain radiographs from prior to cone explant were analyzed for the presence of cement in all four quadrants and compared with results of the retrieval analysis., Results: Mean bone ongrowth was 25%, direct cementation was 24% (31% in tibial cones) and fibrous ongrowth was 29% of the porous surface area of the retrieved cones. There were no significant differences when comparing patterns of bone or fibrous ongrowth or cementation between anterior, posterior medial and lateral porous surfaces for tibia cones, femoral cones or all cones grouped together. Plain radiographs significantly underestimated the amount of cement covering the cone (p = 0.02)., Conclusion: In this retrieval study, we found significant cement extrusion around the porous surface of metaphyseal cones in revision TKAs. Optimizing the cone-bone interface may reduce the risk of cement extrusion and theoretically reduce the risk of aseptic loosening., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier B.V. All rights reserved.)

Introduction: Due to the increasing number of total hip arthroplasties (THA), the number and complexity of revision procedures are also on the rise. For complex cases such as periprosthetic joint infections with soft tissue compromise or for abductor muscle deficiencies, one of the treatment options is a gluteus maximus flap (GMF) that covers dead space and can help restore the failed abductor mechanism. The purpose of this study is to investigate the outcomes of a single-plastic surgeon's series of GMF procedures., Materials and Methods: This retrospective review reports on 57 patients (mean follow-up 39.2 months) undergoing GMF transfers for abductor insufficiency on native hip (N = 16), for abductor insufficiency in aseptic revision THA (rTHA) (N = 16), for soft tissue defects in aseptic rTHA (N = 8) and for soft tissue defects in septic rTHA (N = 17) by a single plastic surgeon over a 10-year period. Revision-free survival and complication rates were assessed and risk factors were analyzed with Cox-regression analysis., Results: The reoperation-free survival rate of GMF for abductor insufficiency in native hips was 100%. GMF procedures for soft tissue defects in septic rTHA had the lowest cumulative revision-free survival (34.3%) and highest reinfection rates (53.9%). More than three prior surgeries (HR = 2.9, p = 0.020), presence of infection (HR = 3.2, p = 0.010) and resistant organisms (HR = 3.1, p = 0.022) significantly increased the risk of revision., Conclusions: GMF is a viable option for addressing abductor insufficiency in native hip joints. However, high revision and complication rates are reported for GMF in septic rTHA. This study highlights the need to clarify the circumstances for which the flap reconstruction will be indicated., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Purpose: The purpose of this study was to evaluate the accuracy of preoperative CT-based Anderson Orthopaedic Research Institute (AORI)-grading and to correlate Computed tomography (CT)-based volumetric defect measurements with intraoperative AORI findings., Methods: 99 patients undergoing revision total knee arthroplasty (rTKA) with preoperative CT-images were identified in an institutional revision registry. CT-image segmentation with 3D-Slicer Software was used to create 3D tibial bone defects which were then graded according to the AORI-classification. The AORI classification categorizes tibial defects into three types: Type I has healthy cortical and cancellous bone near the joint line, Type II involves metaphyseal bone loss affecting one or both condyles, and Type III indicates deficient metaphyseal bone with distal defects and potential damage to the patellar tendon and collateral ligament attachments. These 3D-CT gradings were compared to preoperative X-ray and intraoperative AORI grading. The Friedman test was used to investigate differences between AORI values of each measurement method. Volumetric 3D-bone defect measurements were used to investigate the relationship between AORI classification and volumetric defect size in the three anatomic zones of the tibia., Results: Substantial agreements between preoperative 3D-CT AORI and intraoperative AORI (kappa = 0.663; P < 0.01) and fair agreements between preoperative X-ray AORI and intraoperative AORI grading (kappa = 0.304; P < 0.01) were found. Moderate correlations between volume of remaining bone and intraoperative AORI grading were found in epiphysis (r S  = - 0.529; P < 0.001), metaphysis (r S  = - 0.557; P < 0.001) and diaphysis (r S  = - 0.421; P < 0.001). Small volumetric differences between AORI I vs. AORI II defects and relatively large differences between AORI II and AORI III defects in each zone were detected., Conclusion: Tibial bone defect prediction based on preoperative 3D-CT segmentation showed a substantial agreement with intraoperative findings and is superior to standard radiograph assessment. The relatively small difference in defect volume between AORI I, IIa and IIb suggests that updated CT-based classifications might hold benefits for the planning of rTKA., Level of Evidence: Retrospective Cohort Study; III., (© 2023. The Author(s).)

The combination of an aging population and increased utilization of total hip arthroplasty (THA) is leading to a higher incidence of conversion THA, defined as conversion from previous hip fracture surgery to THA. Conversion THA is a more technically challenging, time-consuming, and costly procedure compared to primary THA and frequently involve more medically complex patients. Thus, the aim of this review is to provide a rubric for surgeons to use when preparing for a conversion THA. We have assessed the compatibility of commonly available extraction devices with popular femoral nails. Furthermore, we review technical pearls for conversion THA including equipment planning, operative setup, intraoperative imaging, extraction sequencing, and troubleshooting commonly encountered obstacles., (© 2023 The Authors.)

Aims: Blood transfusion and postoperative anaemia are complications of total knee arthroplasty (TKA) that are associated with substantial healthcare costs, morbidity, and mortality. There are few data from large datasets on the risk factors for these complications., Methods: We retrospectively reviewed the records of TKA patients from a single tertiary care institution from February 2016 to December 2020. There were a total of 14,901 patients in this cohort with a mean age of 67.9 years (SD 9.2), and 5,575 patients (37.4%) were male. Outcomes included perioperative blood transfusion and postoperative anaemia, defined a priori as haemoglobin level < 10 g/dl measured on the first day postoperatively. In order to establish a preoperative haemoglobin cutoff, we investigated a preoperative haemoglobin level that would limit transfusion likelihood to ≤ 1% (13 g/dl) and postoperative anaemia likelihood to 4.1%. Risk factors were assessed through multivariable Poisson regression modelling with robust error variance., Results: In multivariable analyses, each gram of tranexamic acid reduced transfusion likelihood by 39% (adjusted risk ratio (ARR) 0.61 (95% confidence interval (CI) 0.47 to 0.78)). Risk factors associated with an increased risk of transfusion included operating time (ARR 2.07 (95% CI 1.54 to 2.77)) and drain use (ARR 1.73 (95% CI 1.34 to 2.24))., Conclusion: In this study, we found that increased tranexamic acid dosing, decreased operating time, and decreased drain use may reduce transfusions following TKA. We also established a single preoperative haemoglobin cutoff of 13 g/dl that could help minimize transfusions and reduce postoperative complete blood counts., Competing Interests: M. P. Ast reports IP royalties from OrthAlign, consulting fees from BD, Bioventus, Conformis, OrthAlign, Smith & Nephew, and Surgical Care Affiliates, speaker payments from BD, Convatec, OrthAlign, Smith & Nephew, and Stryker, stock or stock options in ConveyMED, HS2, OrthAlign, Ospitek, Osso VR, and Parvizi Surgical Innovations, and research support from Smith & Nephew, all of which are unrelated to this study. M. P. Ast also reports committee membership, or editorial or governing board membership, on AAOS, AAHKS, Eastern Orthopaedic Association, Journal of Arthroplasty, and Journal of Orthopaedic Innovation and Experience. B. P. Chalmers is on the editorial or governing board of the HSS Journal. A. Gonzalez Della Valle reports IP royalties from Link Orthopaedics, OrthoDevelopment, and OrthoSensor, consulting fees from Johnson & Johnson, Link Orthopaedics, and Naviswiss, stock or stock options in Naviswiss and Wish Bone, research support from Naviswiss, all of which are unrelated to this study. A. Gonzalez Della Valle is also a board or committee member of the Hip Society. J. A. Rodriguez reports IP royalties and consulting fees from ConforMIS, Exatech, Medacta, and Smith & Nephew, stock or stock options in Tracpatch, and research support from DePuy, Exactech, and Smith & Nephew, all of which are unrelated to this study. J. A. Rodriguez is also a board or committee member of AAHKS and the Eastern Orthopaedic Association, and an editorial or governing board member of the Journal of Arthroplasty, Clinical Orthopaedics and Related Research, and the HSS Journal. P. K. Sculco reports consulting fees from Zimmer, Lima Corporate, Intellijoint Surgical, EOS Imaging, and DePuy, speaker payments from DePuy, EOS Imaging, and Intellijoint Surgical, research support from Intellijoint Surgical, and stock or stock options in Intellijoint Surgical and Parvizi Surgical Innovation, all of which are unrelated to this study., (© 2023 The British Editorial Society of Bone & Joint Surgery.)

Background: Leg-length discrepancy (LLD) is a critical factor in component selection and placement for total hip arthroplasty. However, LLD radiographic measurements are subject to variation based on the femoral/pelvic landmarks chosen. This study leveraged deep learning (DL) to automate LLD measurements on pelvis radiographs and compared LLD based on several anatomically distinct landmarks., Methods: Patients who had baseline anteroposterior pelvis radiographs from the Osteoarthritis Initiative were included. A DL algorithm was created to identify LLD-relevant landmarks (ie, teardrop (TD), obturator foramen, ischial tuberosity, greater and lesser trochanters) and measure LLD accurately using six landmark combinations. The algorithm was then applied to automate LLD measurements in the entire cohort of patients. Interclass correlation coefficients (ICC) were calculated to assess agreement between different LLD methods., Results: The DL algorithm measurements were first validated in an independent cohort for all six LLD methods (ICC = 0.73-0.98). Images from 3,689 patients (22,134 LLD measurements) were measured in 133 minutes. When using the TD and lesser trochanter landmarks as the standard LLD method, only measuring LLD using the TD and greater trochanter conferred acceptable agreement (ICC = 0.72). When comparing all six LLD methods for agreement, no combination had an ICC>0.90. Only two (13%) combinations had an ICC>0.75 and eight (53%) combinations had a poor ICC (<0.50)., Conclusion: We leveraged DL to automate LLD measurements in a large patient cohort and found considerable variation in LLD based on the pelvic/femoral landmark selection. This emphasizes the need for the standardization of landmarks for both research and surgical planning., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Adoption of robotic-assisted total hip arthroplasty (RA-THA) systems can improve the accuracy of acetabular cup placement, but no group has reported the learning curve of novel, fluoroscopy-based RA-THA systems., Methods: A learning-curve cumulative summation (LC-CUSUM) analysis was performed on a consecutive series of the first 100 patients who received fluoroscopy-based RA-THA by the study surgeon. Operative times and specific robotic timepoints were compared between learning and proficiency phases., Results: Implementation of fluoroscopy-based RA-THA was associated with a learning curve of 12 cases. A 6-min increase in operative time was seen during the learning phase compared to the proficiency phase (44.3 ± 4.4 vs. 38.0 ± 7.1 min; p < 0.001), with a 3-min longer robotic cup impaction sequence during the learning phase (7.8 ± 1.9 vs. 4.8 ± 1.3 min; p < 0.001)., Conclusion: Adoption of fluoroscopy-based RA-THA is associated with a brief learning curve of 12 cases, with the most significant improvements in surgical efficiency realised during acetabular cup placement., (© 2023 John Wiley & Sons Ltd.)

Background: Total hip arthroplasty (THA) is a safe and effective procedure; however, complications such as dislocation, fracture, and infection still occur. It is still unclear whether the dislocation rate via the posterior approach (PA) is better, equal, or worse than the direct anterior approach. Our aim was to report the primary THA dislocation rate via the PA using enabling technology in a large consecutive series of patients., Methods: A retrospective cohort of 2,888 primary THAs were reviewed at a single, high-volume, academic institution from January 2018 to September 2021. All patients underwent a THA by 4 fellowship-trained orthopaedic surgeons through the PA with enabling technology. Overall dislocation and readmission rates within 90 days and up to 3 years were analyzed., Results: Of the 2,888 procedures, a total of 39 patients had complications related to the surgery during the 3-year follow-up period. There were 10 patients (0.35%) who experienced a dislocation, with half undergoing surgical revision. Of the 39 patients who experienced complications, 37 (1.3%) were readmitted and 2 underwent revision during their hospital stay. Postoperative periprosthetic fractures were the most common cause for readmission and reoperation at a rate of 0.52% and 0.52%, respectively., Conclusion: The dislocation rate of 0.35% is one of the lowest reported rates via the PA at a mean follow up of 2.1 years and is comparable to previously published rates using alternate approaches. Using contemporary THA with enabling technology, the PA is a reliable approach with respect to dislocation and complication rates after primary THA., (Published by Elsevier Inc.)

Aims: When performing revision total hip arthroplasty using diaphyseal-engaging titanium tapered stems (TTS), the recommended 3 to 4 cm of stem-cortical diaphyseal contact may not be available. In challenging cases such as these with only 2 cm of contact, can sufficient axial stability be achieved and what is the benefit of a prophylactic cable? This study sought to determine, first, whether a prophylactic cable allows for sufficient axial stability when the contact length is 2 cm, and second, if differing TTS taper angles (2° vs 3.5°) impact these results., Methods: A biomechanical matched-pair cadaveric study was designed using six matched pairs of human fresh cadaveric femora prepared so that 2 cm of diaphyseal bone engaged with 2° (right femora) or 3.5° (left femora) TTS. Before impaction, three matched pairs received a single 100 lb-tensioned prophylactic beaded cable; the remaining three matched pairs received no cable adjuncts. Specimens underwent stepwise axial loading to 2600 N or until failure, defined as stem subsidence > 5 mm., Results: All specimens without cable adjuncts (6/6 femora) failed during axial testing, while all specimens with a prophylactic cable (6/6) successfully resisted axial load, regardless of taper angle. In total, four of the failed specimens experienced proximal longitudinal fractures, three of which occurred with the higher 3.5° TTS. One fracture occurred in a 3.5° TTS with a prophylactic cable yet passed axial testing, subsiding < 5 mm. Among specimens with a prophylactic cable, the 3.5° TTS resulted in lower mean subsidence (0.5 mm (SD 0.8)) compared with the 2° TTS (2.4 mm (SD 1.8))., Conclusion: A single prophylactic beaded cable dramatically improved initial axial stability when stem-cortex contact length was 2 cm. All implants failed secondary to fracture or subsidence > 5 mm when a prophylactic cable was not used. A higher taper angle appears to decrease the magnitude of subsidence but increased the fracture risk. The fracture risk was mitigated by the use of a prophylactic cable., Competing Interests: J. A. Rodriguez reports royalties from Smith & Nephew, Conformis, Exactech, and Medacta; support for attending meetings and/or travel from Smith & Nephew; stock from Wishbone Medical; and implants for research from Exactech, all of which is unrelated to this work. The remaining authors have no relevant disclosures to this study., (© 2023 Author(s) et al.)

Background: The role of metal hypersensitivity reactions in total knee arthroplasty (TKA) failure is debated. There is no consensus on whether use of a more expensive nickel-free implant is indicated for patients who have preoperative nickel allergy. The purpose of this study was to examine the outcome of patients who have preoperative nickel allergy receiving nickel-free or cobalt chromium (CoCr) implants., Methods: This was a retrospective review of 17,798 patients who underwent 20,324 unilateral primary TKAs between 2016 and 2020. Presence of preoperative nickel allergy was determined (n = 282). Patients were divided into 2 cohorts: those receiving (1) nickel-free or (2) CoCr implants. Clinical outcome scores and revision rates were assessed., Results: 243 received a nickel-free implant and 39 received a CoCr implant. There was no significant difference in revision rate between the cohorts. Survivorship free of revision was 94% in the CoCr implant cohort and 98% in the nickel-free implant cohort (P = .9). When comparing clinical outcome scores between cohorts, there was no difference in preoperative, 6-week or 1-year Knee Osteoarthritis Outcome Score Joint Replacement, Visual Analog Scale (VAS), Lower Extremity Activity Scale, Patient-Reported Outcomes Measurement Information System (PROMIS), and Veterans RAND 12-item scores between cohorts., Conclusion: In this retrospective cohort study, there was no difference in revision rates or clinical outcomes in patients who had a nickel allergy undergoing primary TKA with CoCr or nickel-free implants. Further studies are needed to determine if nickel allergy is an independent risk factor for worse TKA outcomes in general., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Acetabular bone loss is a challenging clinical problem when performing revision total hip arthroplasty (rTHA). This study aimed to evaluate how acetabular bone loss severity influences (1) clinical outcomes and (2) patient-reported outcome measures (PROMs) in rTHA patients., Methods: Patients who underwent rTHA with acetabular component revision from January 2016 to February 2022 were included. Treating surgeons determined Paprosky acetabular bone loss classification intraoperatively. Patients were grouped based on numeric classification (PI, PII, or PIII) to categorize severity. Hip disability and Osteoarthritis Outcome Score for Joint Replacement (HOOS, JR.) and Lower Extremity Activity Scale (LEAS) score were collected preoperatively and 1 year postoperatively. There were 197 patients included. Paprosky classification was PI for 47 patients (23.9%), PII for 113 patients (57.4%), and PIII for 37 patients (18.8%). Mean clinical follow-up was 29 months (range, 1 to 69)., Results: Reoperation rate was 0% (0 patients), 6.2% (7 patients), and 10.8% (4 patients) for PI, PII and PIII groups respectively (P = .052). Mean preoperative HOOS, JR. and LEAS for PI, PII and PIII groups were significantly different, but 1-year postoperative HOOS, JR. and LEAS did not differ significantly. Rates of HOOS, JR. minimal clinically important difference achievement differed significantly between bone loss groups., Conclusion: In this study of rTHA patients, greater acetabular bone loss severity was associated with worse preoperative PROMs and trended toward higher reoperation rate. Postoperative PROMs for bone loss severity groups were statistically similar. Patients who had worse acetabular bone loss were more likely to achieve HOOS, JR. minimal clinically important difference postoperatively., Level of Evidence: III., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: 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., Methods: 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., Results: 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., Conclusion: 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 of Evidence: Level IV, retrospective study., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Minimal clinically important difference (MCID) defines a meaningful clinical change in patient-reported outcome measures. Patient acceptable symptom state (PASS) provides a patient-reported outcome measures threshold value to indicate a satisfactory clinical state. MCID and PASS for revision total knee arthroplasty (rTKA) are ill-defined. Moreover, it is unknown whether diagnosis influences the likelihood of achieving MCID or PASS. The purpose of this study was to calculate MCID for aseptic rTKA and compare the percentage of patients achieving MCID and PASS per diagnosis., Methods: An institutional registry of rTKA was used. First-time aseptic rTKA were included. Demographics, revision diagnosis, preoperative Knee Injury and Osteoarthritis Outcome Score, Jr (KOOS Jr), and 1-year postoperative KOOS Jr were recorded. The 1-year postoperative KOOS Jr PASS score was available. MCID was calculated using distribution-based methods. Three hundred fifty eight first-time aseptic rTKAs were analyzed. The 3 most common diagnoses were aseptic loosening (n = 156), instability (n = 109), and stiffness (n = 37)., Results: The mean KOOS Jr 1-year postoperative MCID for rTKA was 10.3. Overall, 75.4% achieved MCID and 56.9% achieved PASS. The percentage of patients per diagnosis achieving MCID and PASS, respectively, were periprosthetic fracture (100, 44), aseptic loosening (94, 60), implant fracture (88, 63), stiffness (60, 38), instability (59, 61), polyethylene wear/osteolysis (57, 57), and metal allergy (44, 33)., Conclusion: Aseptic rTKA MCID is 10.3 for KOOS Jr at 1 year postoperatively. rTKA outcomes vary depending on preoperative diagnosis. Even in diagnoses with a high proportion of MCID achieved, less than 2/3 of patients achieved PASS, suggesting rTKA provides noticeable improvement but may not return patients to a satisfactory state., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: As the demand for total hip arthroplasty (THA) rises, a predictive model for THA risk may aid patients and clinicians in augmenting shared decision-making. We aimed to develop and validate a model predicting THA within 10 years in patients using demographic, clinical, and deep learning (DL)-automated radiographic measurements., Methods: Patients enrolled in the osteoarthritis initiative were included. DL algorithms measuring osteoarthritis- and dysplasia-relevant parameters on baseline pelvis radiographs were developed. Demographic, clinical, and radiographic measurement variables were then used to train generalized additive models to predict THA within 10 years from baseline. A total of 4,796 patients were included [9,592 hips; 58% female; 230 THAs (2.4%)]. Model performance using 1) baseline demographic and clinical variables 2) radiographic variables, and 3) all variables was compared., Results: Using 110 demographic and clinical variables, the model had a baseline area under the receiver operating curve (AUROC) of 0.68 and area under the precision recall curve (AUPRC) of 0.08. Using 26 DL-automated hip measurements, the AUROC was 0.77 and AUPRC was 0.22. Combining all variables, the model improved to an AUROC of 0.81 and AUPRC of 0.28. Three of the top five predictive features in the combined model were radiographic variables, including minimum joint space, along with hip pain and analgesic use. Partial dependency plots revealed predictive discontinuities for radiographic measurements consistent with literature thresholds of osteoarthritis progression and hip dysplasia., Conclusion: A machine learning model predicting 10-year THA performed more accurately with DL radiographic measurements. The model weighted predictive variables in concordance with clinical THA pathology assessments., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Without a gold-standard test, recent periprosthetic joint infections (PJI) literature has explored the utility of combining serological results, with promising findings. However, previous studies evaluated fewer than 200 patients and often studied only 1 to 2 test combinations. The purpose of this study was to accumulate a large single-institution cohort of revision total joint arthroplasty (rTJA) patients to determine the diagnostic utility of combination serum biomarkers to identify PJI., Methods: A single institution longitudinal database was assessed to identify all patients who underwent rTJA from 2017 to 2020. There were 1,363 rTJA patients (715 rTKA patients and 648 rTHA patients) including 273 PJI cases (20%) analyzed. The PJI was diagnosed post-rTJA utilizing 2011 Musculoskeletal Infection Society (MSIS) criteria. Erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), D-dimer, and interleukin 6 (IL-6) were systematically collected for all patients., Results: The rTKA combination markers of CRP + ESR (sensitivity: 78.3%, specificity: 88.8%, positive predictive value (PPV): 70.0%, negative predictive value (NPV): 92.5%), CRP + D-dimer (sensitivity: 60.5%, specificity: 92.6%, PPV: 63.4%, NPV: 91.7%), and CRP + IL-6 (sensitivity: 38.5%, specificity: 100.0%, PPV: 100.0%, NPV: 92.9%) all yielded higher specificity than CRP alone (sensitivity: 94.4%, specificity: 75.0%, PPV: 55.5%, NPV: 97.6%). Similarly, the rTHA combination markers of CRP + ESR (sensitivity: 70.1%, specificity: 88.8%, PPV: 58.1%, NPV: 93.1%), CRP + D-dimer (sensitivity: 57.1%, specificity: 90.1%, PPV: 43.2%, NPV: 94.1%), and CRP + IL-6 (sensitivity: 21.4%, specificity: 98.4%, PPV: 60.0%, NPV: 91.7%) all yielded higher specificity than CRP alone (sensitivity: 84.7%, specificity: 77.5%, PPV: 45.4%, NPV: 95.8%)., Conclusion: Overall, in diagnosing PJI for both rTKA and rTHA, 2-marker combinations yielded higher specificity, while 3-marker combinations yielded higher sensitivity compared to CRP alone. However, compared to all 2-marker and 3-marker combinations, CRP demonstrated superior overall diagnostic utility. These findings suggest that routine combination testing of markers for PJI diagnosis may be excessive and an unnecessary use of resources, especially in resource-limited situations., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Aims: Mid-level constraint designs for total knee arthroplasty (TKA) are intended to reduce coronal plane laxity. Our aims were to compare kinematics and ligament forces of the Zimmer Biomet Persona posterior-stabilized (PS) and mid-level designs in the coronal, sagittal, and axial planes under loads simulating clinical exams of the knee in a cadaver model., Methods: We performed TKA on eight cadaveric knees and loaded them using a robotic manipulator. We tested both PS and mid-level designs under loads simulating clinical exams via applied varus and valgus moments, internal-external (IE) rotation moments, and anteroposterior forces at 0°, 30°, and 90° of flexion. We measured the resulting tibiofemoral angulations and translations. We also quantified the forces carried by the medial and lateral collateral ligaments (MCL/LCL) via serial sectioning of these structures and use of the principle of superposition., Results: Mid-level inserts reduced varus angulations compared to PS inserts by a median of 0.4°, 0.9°, and 1.5° at 0°, 30°, and 90° of flexion, respectively, and reduced valgus angulations by a median of 0.3°, 1.0°, and 1.2° (p ≤ 0.027 for all comparisons). Mid-level inserts reduced net IE rotations by a median of 5.6°, 14.7°, and 17.5° at 0°, 30°, and 90°, respectively (p = 0.012). Mid-level inserts reduced anterior tibial translation only at 90° of flexion by a median of 3.0 millimetres (p = 0.036). With an applied varus moment, the mid-level insert decreased LCL force compared to the PS insert at all three flexion angles that were tested (p ≤ 0.036). In contrast, with a valgus moment the mid-level insert did not reduce MCL force. With an applied internal rotation moment, the mid-level insert decreased LCL force at 30° and 90° by a median of 25.7 N and 31.7 N, respectively (p = 0.017 and p = 0.012). With an external rotation moment, the mid-level insert decreased MCL force at 30° and 90° by a median of 45.7 N and 20.0 N, respectively (p ≤ 0.017 for all comparisons). With an applied anterior load, MCL and LCL forces showed no differences between the two inserts at 30° and 90° of flexion., Conclusion: The mid-level insert used in this study decreased coronal and axial plane laxities compared to the PS insert, but its stabilizing benefit in the sagittal plane was limited. Both mid-level and PS inserts depended on the MCL to resist anterior loads during a simulated clinical exam of anterior laxity., Competing Interests: M. B. Cross reports royalties or licenses from Depuy Synthes and PSI, consulting fees from Depuy Synthes, Exactech, and 3M, payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Depuy Synthes and 3M, and stock or stock options in Ospitek, PSI, and Intellijoint, all of which are unrelated to this article. D. J. Mayman reports royalties or licenses from Orthalign and Smith & Nephew, and stock or stock options in Imagen, Orthalign, Smith & Nephew, Wishbone, Micare Path, and Cymedica, all of which are unrelated to this article. C. W. Imhauser reports payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Corin Medical, unrelated to this study. P. K. Sculco reports consulting fees from Zimmer Biomet, Intellijoint Surgical, Lima Corporate, Depuy Synthes, and ATEC, payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Zimmer Biomet, stock or stock options in Parvizi Surgical Innovation and Intellijoint Surgical, and receipt of equipment, materials, drugs, medical writing, gifts or other services, all of which are unrelated to this study., (© 2023 Author(s) et al.)

Background: Knee instability is a leading cause of dissatisfaction following total knee arthroplasty (TKA). Instability can involve abnormal laxity in multiple directions including varus-valgus (VV) angulation, anterior-posterior (AP) translation, and internal-external rotation (IER). No existing arthrometer objectively quantifies knee laxity in all three of these directions. The study objectives were to verify the safety and assess reliability of a novel multiplanar arthrometer., Methods: The arthrometer utilized a five degree-of-freedom instrumented linkage. Two examiners each conducted two tests on the leg that had received a TKA of 20 patients (mean age 65 years (range, 53-75); 9 men, 11 women), with nine and eleven distinct patients tested at 3-month and 1-year postoperative time points, respectively. AP forces from -10 to 30 Newtons, VV moments of ±3 Newton-meters, and IER moments of ±2.5 Newton-meters were applied to each subject's replaced knee. Severity and location of knee pain during testing were assessed using a visual analog scale. Intraexaminer and interexaminer reliabilities were characterized using intraclass correlation coefficients., Results: All subjects successfully completed testing. Pain during testing averaged 0.7 (out of possible 10; range, 0-2.5). Intraexaminer reliability was >0.77 for all loading directions and examiners. Interexaminer reliability and 95% confidence intervals were 0.85 (0.66-0.94), 0.67 (0.35-0.85), and 0.54 (0.16-0.79) in the VV, IER, and AP directions, respectively., Conclusion: The novel arthrometer was safe for evaluating AP, VV, and IER laxities in subjects who had received TKA. This device could be used to examine relationships between laxity and patient perceptions of knee instability., (Copyright © 2023. Published by Elsevier Inc.)

Background: Arthrofibrosis after anterior cruciate ligament reconstruction (ACLR) is a notable but uncommon complication of ACLR. To improve range of motion after ACLR, aggressive physical therapy, arthroscopic/open lysis of adhesions, and revision surgery are currently used. Manipulation under anesthesia (MUA) is also a reasonable choice for an appropriate subset of patients with inadequate range of motion after ACLR. Recently, the correlation between anticoagulant usage and arthrofibrosis after total knee arthroplasty has become an area of interest. The purpose of this study was to determine whether anticoagulant use has a similar effect on the incidence of MUA after ACLR., Methods: The Mariner data set of the PearlDiver database was used to conduct this retrospective cohort study. Patients with an isolated ACLR were identified by using Current Procedural Terminology codes. Patients were then stratified by MUA within 2 years of ACLR, and the use of postoperative anticoagulation was identified. In addition, patient demographics, medical comorbidities, and timing of ACLR were recorded. Univariate and multivariable analyses were used to model independent risk factors for MUA., Results: We identified 216,147 patients who underwent isolated ACLR. Of these patients, 3,494 (1.62%) underwent MUA within 2 years. Patients who were on anticoagulants after ACLR were more likely to require an MUA (odds ratio [OR]: 2.181; P < 0.001), specifically low-molecular-weight heparin (OR: 2.651; P < 0.001), warfarin (OR: 1.529; P < 0.001), and direct factor Xa inhibitors (OR: 1.957; P < 0.001)., Discussion: In conclusion, arthrofibrosis after ACLR is associated with the use of preoperative or postoperative thromboprophylaxis. Healthcare providers should be aware of increased stiffness among these patients and treat them aggressively., (Copyright © 2022 by the American Academy of Orthopaedic Surgeons.)

Background: Fractures of the polyethylene post are a rare but known complication after posterior-stabilized (PS) total knee arthroplasty (TKA). We evaluated the polyethylene and patient characteristics for 33 primary PS polyethylene components that were revised with fractured posts., Methods: We identified 33 PS inserts revised between 2015 and 2022. Patient characteristics collected included age at index TKA, sex, body mass index, length of implantation (LOI), and patient-reported details on events surrounding the post fracture. Implant characteristics recorded were manufacturer, cross-linking properties (highly cross-linked polyethylene [XLPE] versus ultra-high molecular weight polyethylene [UHMWPE]), wear characteristics based on subjective scoring of the articular surfaces and scanning electron microscopy (SEM) of fracture surfaces. Mean age at index surgery was 55 years (range, 35 to 69), mean body mass index was 29.5 (range, 18.5 to 37.2), and mean LOI was 10.0 (range, 4 to 26)., Results: Total surface damage scores were significantly higher in the UHMWPE group versus the XLPE group (57.3 versus 44.2, P = .003). SEM demonstrated fracture initiation at the posterior edge of the post in 10 of 13 cases. UHMWPE fracture surfaces posts had more tufted, irregularly clamshell features, while XLPE posts had more precise clamshell marking and a diamond pattern in the region of acute, final fracture., Conclusion: Characteristics of PS post fracture differed between XLPE and UHMWPE implants, with fractures occurring in the XLPE with less generalized surface damage, after a shorter LOI, and with SEM evaluation indicative of a more brittle fracture pattern., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: Achieving adequate implant fixation is critical to optimize survivorship and postoperative outcomes after revision total knee arthroplasty (rTKA). Three anatomical zones (ie, epiphysis, metaphysis, and diaphysis) have been proposed to assess fixation, but are not well-defined. The purpose of the study was to develop a deep learning workflow capable of automatically delineating rTKA zones and cone placements in a standardized way on postoperative radiographs., Methods: A total of 235 patients who underwent rTKA were randomly partitioned (6:2:2 training, validation, and testing split), and a U-Net segmentation workflow was developed to delineate rTKA fixation zones and assess revision cone placement on anteroposterior radiographs. Algorithm performance for zone delineation and cone placement were compared against ground truths from a fellowship-trained arthroplasty surgeon using the dice segmentation coefficient and accuracy metrics., Results: On the testing cohort, the algorithm defined zones in 98% of images (8 seconds/image) using anatomical landmarks. The dice segmentation coefficient between the model and surgeon was 0.89 ± 0.08 (interquartile range [IQR]:0.88-0.94) for femoral zones, 0.91 ± 0.08 (IQR: 0.91-0.95) for tibial zones, and 0.90 ± 0.05 (IQR:0.88-0.94) for all zones. Cone identification and zonal cone placement accuracy were 98% and 96%, respectively, for the femur and 96% and 89%, respectively, for the tibia., Conclusion: A deep learning algorithm was developed to automatically delineate revision zones and cone placements on postoperative rTKA radiographs in an objective, standardized manner. The performance of the algorithm was validated against a trained surgeon, suggesting that the algorithm demonstrated excellent predictive capabilities in accordance with relevant anatomical landmarks used by arthroplasty surgeons in practice., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: There is a lack of consensus on optimal skin closure and dressing strategies to reduce early wound complication rates after primary total hip arthroplasty (THA) and total knee arthroplasty (TKA)., Methods: All 13,271 patients at low risk for wound complications undergoing primary, unilateral THA (7,816), and TKA (5,455) for idiopathic osteoarthritis at our institution between August 2016 and July 2021 were identified. Skin closure, dressing type, and postoperative events related to wound complications were recorded during the first 30 postoperative days., Results: The need for unscheduled office visits to address wound complications was more frequent after TKA than THA (2.74 versus 1.78%, P < .001), and after direct anterior versus posterior approach THA (2.94 versus 1.39%, P < .001). Patients who developed a wound complication, had a mean of 2.9 additional office visits. Compared to the use of topical adhesives, skin closure with staples had the highest risk of wound complications (odds ratio 1.8 [1.07-3.11], P = .028). Topical adhesives with polyester mesh had higher rates of allergic contact dermatitis than topical adhesives without mesh (1.4 versus 0.5%, P < .0001)., Conclusion: Wound complications after primary THA and TKA were often self-limited but increased burden on the patient, surgeon, and care team. These data, which suggest different rates of certain complications with different skin closure strategies, can inform a surgeon on optimal closure methods in their practice. Adoption of the skin closure technique with the lowest risk of complications in our hospital would conservatively result in a reduction of 95 unscheduled office visits and save a projected $585,678 annually., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: A specific total knee arthroplasty (TKA) implant system was recently recalled for high incidence of early polymeric wear and osteolysis. We analyzed the early outcomes of aseptic revision with these implants., Methods: We identified 202 aseptic revision TKAs of this implant system performed at a single institution between 2010 and 2020. Revision indications included aseptic loosening (n = 120), instability (n = 55), and polymeric wear/osteolysis (n = 27). Components were revised in 145 cases (72%) and isolated polyethylene insert exchange occurred in 57 cases (28%). Kaplan-Meier and Cox proportional hazards analyses were used to determine survivorship free from all-cause rerevision and rerevision risk factors., Results: At 2 and 5 years, survivorship free from all-cause rerevision was 89 and 76% in the polyethylene exchange cohort versus 92 and 84% in the component revision cohort (P = .5). At 2 and 5 years, survivorship in revision with components from the same manufacturer was 89 and 80% compared to 95 and 86% in revision with components from a different manufacturer (P = .2). Among re-revisions (n = 30), cones (37%), sleeves (7%), hinge/distal femoral replacement implants were frequently used (13%). Men had increased risk for rerevision (hazard ratio = 2.3, P = .04)., Conclusion: In this series of aseptic revision TKAs performed on a now-recalled implant system, survivorship free from rerevision was lower than expected when components from the same manufacturer were utilized, but comparable to contemporary reports when both the components were revised with an alternative implant system. Metaphyseal fixation with cones and sleeves as well as highly constrained implants was frequently utilized at time of rerevision TKA., Level of Evidence: Level IV., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background: The Coronal Plane Alignment of the Knee (CPAK) classification allows for knee phenotyping which can be used in preoperative planning prior to total knee arthroplasty. We used deep learning (DL) to automate knee phenotyping and analyzed CPAK distributions in a large patient cohort., Methods: Patients who had full-limb radiographs from a large arthritis database were retrospectively included. A DL algorithm was developed to automate CPAK knee alignment parameters including the lateral distal femoral, medial proximal tibia, hip-knee-ankle, and joint line obliquity angles. The algorithm was validated against a fellowship-trained arthroplasty surgeon. After applying the algorithm in a large patient cohort (n = 1,946 knees), the distribution of CPAK was compared across patient sex and baseline Kellgren-Lawrence (KL) scores., Results: There was no significant difference in the CPAK angles (n = 140, P = .66-.98, inter-class correlation coefficient = 0.89-0.91) or phenotype classifications made by the algorithm and surgeon (P = .96). The deep learning algorithm measured the entire cohort (n = 1,946 knees, mean age 61 years [range, 46 to 80 years], 51% women) in < 5 hours. Women had more valgus CPAK phenotypes than men (P < .05). Patients who had higher KL grades at baseline (2 to 4) were more varus using the CPAK classification compared to lower KL grades (0 to 1) (P < .05)., Conclusion: We applied an accurate, automated DL algorithm on a large patient cohort to determine knee phenotypes, helping to validate and strengthen the CPAK classification system. Analyses revealed that sex-specific and major bone loss adjustments may need to be accounted for when using this system., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Controlling blood loss is a crucial aspect of orthopedic surgery. Hemostatic agents can be used intraoperatively in combination with antifibrinolytics as part of an overall strategy to limit blood loss. Several new hemostatic agents have recently come to the market designed specifically for vascular surgery but have found uses in other surgical fields, including orthopedics. This article reviews the mechanisms of action and best uses of various mechanical hemostats, active hemostats, flowable hemostats, and fibrin sealants for achieving hemostasis in orthopedic surgery. Mechanical and active hemostats have been reported to successfully decrease blood loss from cancellous bone, capillaries, and venules. Flowable hemostats are generally favorable for use in small spaces where the swelling capabilities of mechanical and active hemostats can be detrimental to surrounding structures. Sealants are best used for closing defects in tissues., Competing Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: J.L.B. reports relationships with Globus Medical, KCI, and LimaCorporate. M.P.F. reports relationships LimaCorporate, Wishbone, Insight, and Mekanika. A.V.C. reports a relationship with Heraeus Medical. P.K.S. reports relationships with DePuy/Johnson & Johnson, EOS Imaging, Intellijoint Surgical, LimaCorporate, Parvizi Surgical Innovation, and Zimmer. E.B.G. reports relationships with DePuy/Johnson & Johnson Company and Zimmer-Biomet. The other authors declare no potential conflicts of interest., (© The Author(s) 2022.)

Background: While database studies have become more prevalent in the literature, there is concern over their value. In addition, the questions they are suitable to answer are limited. Questions/Purposes : We sought to determine the incidence of database studies in the orthopedic literature and in each subspecialty. In addition, we wanted to assess the impact of database studies on the literature by determining whether citations and Altmetric Attention Scores (AAS) varied by study type (studies using internal or external databases and those not using databases). Methods : We searched PubMed for articles published in impactful orthopedic surgery journals in the year 2018. All articles were discoverable on the Altmetric explorer portal database. Impact was determined by journal impact factor. Study design, subspecialty, number of citations, and AAS were obtained. Univariable analyses were conducted between study type, demographic variables, and the outcome of either citation count or AAS. Multivariable analyses were performed to identify independent predictors of the primary outcomes. Subgroup analyses were performed to differentiate the impact of external and internal database studies compared with non-database studies. Results : A total of 2684 total articles were eligible for inclusion. Of these, 366 studies (13.6%) were database studies. Hip and knee articles had the greatest incidence of database studies. Database studies had significantly more citations (5.9 vs 4.0) and significantly higher AAS (12.8 vs 11.3) compared with non-database studies. External database studies had significantly more citations (6.7 vs 4.8) and significantly higher AAS (14.0 vs 10.7) than internal database studies. Internal database studies had higher traditional citation counts but similar AAS to non-database studies. Conclusions : In 2018, database studies in well-reputed orthopedic journals had a greater number of citations but similar AAS compared with non-database studies. Further studies are warranted., Competing Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Peter K. Sculco, MD, reports relationships with Intelljoint Surgical; DePuy, A Johnson & Johnson Company; Zimmer; Lima Corporate; EOS Imaging; and Parvizi Surgical Innovation. Savyasachi C. Thakkar, MD, reports relationships with OrthoAlign and KCI. The other authors report no potential conflicts of interest., (© The Author(s) 2022.)

Background: Total knee arthroplasty (TKA) is rarely performed in patients under 21 years old, but the frequency of utilization of TKA in this population in the United States is not known. The purpose of this study was to evaluate trends in the use of TKA in patients <21 in the United States. Additionally, we aimed to determine the characteristics of these patients and the hospitals in which this procedure is performed., Methods: We retrospectively reviewed the Kids' Inpatient Database, a national weighted sample of all inpatient hospital admissions in the United States in patients <21 years of age. We used International Classification of Diseases, Ninth Revision (ICD-9) and ICD-10 codes to identify patients undergoing TKA from 2000 to 2019 and determine a primary diagnosis. Descriptive statistics were calculated using the appropriate sample weights., Results: The total weighted number of TKAs performed in patients <21 years from 2000 to 2019 was 1,535. There were 70.9% of TKAs performed for a primary diagnosis of tumor, and the use of TKA for malignant tumors has increased. In contrast, the use of TKA for inflammatory arthritis/juvenile idiopathic arthritis decreased significantly over the study period. The majority of TKAs were performed in urban teaching hospitals with a large bed size., Conclusion: Approximately 1,535 TKAs have been performed in patients <21 years from 2000 to 2019 in the United States. The majority of these procedures were performed for reconstruction after resection of a malignant tumor. The rate of TKA for inflammatory arthritis/juvenile idiopathic arthritis has decreased over the past two decades., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: The tibial component in total knee arthroplasty (TKA) is often chosen to maximize coverage of the tibial cut, which can result in excessive internal rotation of the component. Optimal rotational alignment may require a smaller baseplate with suboptimal coverage that could threaten fixation. We asked: "does undersizing the tibial component of a cementless TKA to gain external rotation increase the risk of bone failure?", Methods: We developed computational finite element (FE) analysis models from the computed tomography (CT) scans of 12 patients scheduled for primary TKA. The models were implanted with a cementless tibial baseplate that maximized coverage and one or two sizes smaller and externally rotated by 5°. We calculated the risk of bone collapse under loads representative of stair ascent., Results: Undersizing the implant increased the area at risk of collapse for eight patients. However, the area at risk of collapse for the undersized implant (range, 5.2%-16.4%) was no different (P = .24) to the optimally sized implant (range, 4.5%-17.9%). The bone at risk of collapse was concentrated along the posterior edge of the implant. The area at risk of collapse was not proportional to implant size, and for four subjects undersizing the implant actually decreased the area at risk of collapse., Conclusion: While implants should maximize coverage of the tibial cut and seek support on dense bone, undersizing the tibial component to gain external rotation had minimal impact on the load transfer to the underlying bone. This FE analysis model of a cementless tibial baseplate may require further validation and additional studies to investigate the long-term biomechanical effects of undersizing the tibial baseplate. In conclusion, while surgeons should strive to use the appropriate tibial baseplate for each patient, our model identified only minor biomechanical consequences of undersizing the implant for the immediate postoperative bone-implant interaction and implant subsidence., (Copyright © 2022 Elsevier Inc. All rights reserved.)

The purpose of this study was to assess mid-term survivorship following primary total knee arthroplasty (TKA) with Optetrak Logic components and identify the most common revision indications at a single institution. We identified a retrospective cohort of 7,941 Optetrak primary TKAs performed from January 2010 to December 2018. We reviewed the intraoperative findings of 369 TKAs that required revision TKA from January 2010 to December 2021 and the details of the revision implants used. Kaplan-Meier analysis was used to determine survivorship. Cox regression analysis was used to examine the impact of patient variables and year of implantation on survival time. The estimated survivorship free of all-cause revision was 98% (95% confidence interval (CI) 97% to 98%), 95% (95% CI 95% to 96%), and 86% (95% CI 83% to 88%) at two, five, and ten years, respectively. In 209/369 revisions there was a consistent constellation of findings with varying severity that included polyethylene wear and associated synovitis, osteolysis, and component loosening. This failure mode, which we refer to as aseptic mechanical failure, was the most common revision indication. The mean time from primary TKA to revision for aseptic mechanical failure was five years (5 months to 11 years). In this series of nearly 8,000 primary TKAs performed with a specific implant, we identified a lower-than-expected mid-term survivorship and a high number of revisions with a unique presentation. This study, along with the recent recall of the implant, confirms the need for frequent monitoring of patients with Optetrak TKAs given the incidence of polyethylene failure, osteolysis, and component loosening., Competing Interests: M. P. Figgie reports royalties and consulting fees from Lima and Wishbone, and patents and leadership or fiduciary roles for Wishbone, and stock or stock options in Wishbone and HS2, all unrelated to this study. E. Gausden reports consulting fees from Zimmer Biomet and Depuy, unrelated to this study. P. K. Sculco reports royalties from Lima, consulting fees from Zimmer Biomet, DePuy, and Lima, and stock or stock options in Intellijoint Surgical, all unrelated to this study. T. P. Sculco reports royalties from Exatech, support for attending meetings and/or travel from HSS, all unrelated to this study. T. P. Sculco is also President of OREF. G. Weststrich reports royalties from Stryker, consulting fees and speaker payments from Stryker and Ethicon, and a leadership or fiduciary role for the Eastern Orthopedic Association, all of which are unrelated to this study., (© 2023 The British Editorial Society of Bone & Joint Surgery.)

Background: Periprosthetic femur fracture following total knee arthroplasty (TKA) is a devastating complication. Although trauma-related periprosthetic femur fractures have been well studied, early atraumatic insufficiency periprosthetic fractures (IPFs) are gaining attention. We present the largest IPF series to date to better understand and prevent this complication., Methods: A retrospective study of all patients who underwent a revision surgery for periprosthetic fracture within 6 months of primary TKA between 2007 and 2020 was performed. Patient demographics, preoperative radiographs, implant details, and fracture radiographs were reviewed. Alignment measurements and fracture characteristics were assessed., Results: Sixteen patients met criteria (rate 0.05%), and 11 had posterior-stabilized TKAs. The mean age was 79 years, mean body mass index was 31 kg/m 2 , and 94% (15/16) were female. Seven (47%) patients had a confirmed history of osteoporosis. IPF occurred on average 4 weeks (range, 4 days-13 weeks) after the index TKA. Overall, 12 of 16 (73%) had preoperative valgus deformities, and 11 patients (10 valgus, 1 varus) had preoperative deformities >10 degrees. A characteristic radiographic appearance of femoral condylar impaction and collapse was noted in 12 of 16 cases (75%); 11 of these 12 fractures (92%) involved the unloaded compartment based on preoperative varus/valgus deformity., Conclusions: Patients who developed IPFs were most commonly elderly, obese women with osteoporosis and severe preoperative valgus deformities. The apparent mechanism of failure was overloading of previously unloaded osteopenic femoral condyle. In high-risk patients, the use of a cruciate-retaining femoral component or a femoral stem for a posterior-stabilized femur may be considered to help avoid this catastrophic complication., (© 2023 The Authors.)

Purpose: To (1) develop a deep-learning (DL) algorithm capable of producing limb-length and knee-alignment measurements, and (2) determine the association between limb-length discrepancy (LLD), coronal-plane alignment, osteoarthritis (OA) severity, and patient-reported knee pain., Methods: A multicenter, prospective patient cohort from the Osteoarthritis Initiative between 2004 and 2015 with full-limb standing radiographs at 12 month follow-up was included. A convolutional neural network was developed to automate measurements of the hip-knee-ankle (HKA) angle, femur, and tibia lengths, and LLD. At 12 month follow-up, patients reported their frequency of knee pain since enrollment and current level of knee pain., Results: A total of 1011 patients (2022 knees, 52.3% female) with an average age of 61.2 ± 9.0 years were included. The algorithm performed 12,312 measurements in 5.4 h. ICC values of HKA and LLD ranged between 0.87 and 1.00 when compared against trained radiologist measurements. Knees producing pain most days of the month were significantly more varus (mean HKA:- 3.9° ± 2.8°) or valgus (mean HKA:2.8° ± 2.3°) compared to knees that did not produce any pain (p < 0.05). In varus knees, those producing pain on most days were part of the shorter limb compared to nonpainful knees (p < 0.05). Baseline Kellgren-Lawrence grade was significantly associated with HKA magnitude, LLD, and pain frequency at 12 month follow-up (p < 0.05 all)., Conclusion: A higher frequency of knee pain was associated with more severe coronal plane deformity, with valgus deviation being one degree less than varus on average, suggesting that the knee tolerates less valgus deformation before symptoms become more consistent. Knee pain frequency was also associated with greater LLD and baseline KL grade, suggesting an association between radiographically apparent joint degeneration and pain frequency., Level of Evidence: IV case series., (© 2022. The Author(s) under exclusive licence to European Society of Sports Traumatology, Knee Surgery, Arthroscopy (ESSKA).)

Background: Tranexamic acid (TXA) reduces rates of blood transfusion for total hip arthroplasty (THA) and total knee arthroplasty (TKA). Although the use of oral TXA rather than intravenous (i.v.) TXA might improve safety and reduce cost, it is not clear whether oral administration is as effective., Methods: This noninferiority trial randomly assigned consecutive patients undergoing primary THA or TKA under neuraxial anaesthesia to either one preoperative dose of oral TXA or one preoperative dose of i.v. TXA. The primary outcome was calculated blood loss on postoperative day 1. Secondary outcomes were transfusions and complications within 30 days of surgery., Results: Four hundred participants were randomised (200 THA and 200 TKA). The final analysis included 196 THA patients (98 oral, 98 i.v.) and 191 TKA patients (93 oral, 98 i.v.). Oral TXA was non-inferior to i.v. TXA in terms of calculated blood loss for both THA (effect size=-18.2 ml; 95% confidence interval [CI], -113 to 76.3; P<0.001) and TKA (effect size=-79.7 ml; 95% CI, -178.9 to 19.6; P<0.001). One patient in the i.v. TXA group received a postoperative transfusion. Complication rates were similar between the two groups (5/191 [2.6%] oral vs 5/196 [2.6%] i.v.; P=1.00)., Conclusions: Oral TXA can be administered in the preoperative setting before THA or TKA and performs similarly to i.v. TXA with respect to blood loss and transfusion rates. Switching from i.v. to oral TXA in this setting has the potential to improve patient safety and decrease costs., (Copyright © 2022 British Journal of Anaesthesia. Published by Elsevier Ltd. All rights reserved.)

Background: Prior investigations of total hip arthroplasty (THA) have studied the effects of prosthetic femoral head size and stem offset on hip range of motion (ROM), impingement risk, and overall hip stability to optimize the return to activities of daily living. However, the relationship between femoral head length and hip ROM, specifically external rotation (ER), has not been evaluated. The aim of our study was to intraoperatively assess how femoral head length affects hip ROM during a posterior approach THA., Methods: Thirty-two patients undergoing a primary elective THA through a posterior approach were prospectively included. After final femoral stem insertion, femoral head trials were performed using the targeted head length, followed by the shorter (-3.0 to -3.5 mm) and longer (+3.0 to +4.0 mm) head length configurations. At each length, hip ER was measured using an intraoperative goniometer from an imageless navigation system. ER values across the three head lengths were compared using a repeated-measures analysis of variance and paired t -tests., Results: Varying femoral head lengths demonstrated a statically significant and reproducible effect on intraoperative ER range (analysis of variance; P < .001) in each patient. An increased femoral head length (mean 3.4 mm) significantly decreased ( P < .001) ER range by 10.8 ± 3.3° while a shortened femoral head length (mean 3.5 mm) significantly increased ( P < .001) the ER ROM by 6.0 ± 3.8°., Conclusions: The results of this study demonstrate the sensitivity of hip ROM to incremental changes in femoral head length. As ER is important for activities of daily living, inadvertent lengthening should be avoided., (© 2022 The Authors.)

Background: The objective of this study was to evaluate the reoperation and complication rate following trochanteric plate fixation of greater trochanter (GT) periprosthetic femur fractures associated with total hip arthroplasty and to identify risk factors for subsequent reoperation, nonunion, and hardware failure (plate/cable breakage or migration)., Methods: Between 2010 and 2020, 44 patients who had 44 periprosthetic greater trochanter fractures at mean follow up of 2 years were retrospectively reviewed. Initial injury radiographs as well as immediate and final follow-up radiographs were evaluated. Subsequent reoperations, nonunion, and cases of hardware failure were identified. There were 22 (50%) Vancouver B2 fractures and 22 (50%) Vancouver A fractures., Results: The 2-year cumulative probability of any subsequent reoperation was 20%. There were 9 total subsequent reoperations. The trochanteric fracture went on to nonunion in 14 patients (39%), and hardware failure occurred in 10 (28%) patients. A trochanteric bolt was used in addition to the trochanteric plate in 6 patients (14%), of which 4 (67%) patients had trochanteric plate displacement and 3 (50%) patients had trochanteric nonunion. Displacement of the greater trochanter prior to fixation was a predictor of subsequent nonunion (77% versus 23%, P = .02)., Conclusion: In this large contemporary series, there was a high incidence of reoperation (20%) with in the first 2-years following plating of periprosthetic GT fractures, as well as a high rate of nonunion (39%), and hardware failure (28%). Displacement of the GT prior to plating predicted nonunion., Level of Evidence: Level IV, retrospective observational study., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Lymphocyte transformation testing (LTT) is often used in the workup for possible metal allergy after total knee arthroplasty (TKA) but the correlation of this test with other diagnostic metal-allergy findings in patients undergoing revision TKA for suspected metal allergy has not been established. A single-center, single-surgeon cohort of 19 TKAs in which both components were revised for presumed implant-related metal allergy based on history, physical, and LTT testing, to nonnickel-containing implants were retrospectively identified. Histopathologic samples obtained intraoperatively were semiquantitatively analyzed using both the Hospital for Special Surgery (HSS) synovial pathology score and the Campbell aseptic lymphocyte-dominant vasculitis-associated lesion (ALVAL) score. As histopathology control group, we included in the study an additional cohort of 17 patients who received aseptic revision TKA and had no history of reported or tested metal sensitivity. All preoperative LTT results were highly reactive to nickel. However, this did not correlate with local periarticular tissue response in 18 of 19 cases which demonstrated a low HSS synovial score (mean: 3.8 ± 2.8, of a maximum score of 28) and the low Campbell ALVAL scores (mean: 2.5/10 ± 1.3, of a maximum score of 10). There were not any significant differences between the study group (suspected implant-related metal allergy) and the control group (nonsuspected implant-related metal allergy) in regard to (1) the Campbell score and (2) the HSS synovial inflammatory score. Knee Society Clinical Rating System (KSCRS) function score improved significantly after revision (mean postoperative increase: 34.0 ± 17. 2; p  < 0.001), as well as mean visual analog scale (VAS) pain (mean postoperative decrease: 33.3 ± 26.4; p  < 0.01) score. The short-term survival rate (at mean follow-up of 26.1 months) of this patient cohort was 100%. In this cohort of revised TKA patients with suspected nickel allergy based on clinical presentation and LTT positive results, intraoperative histopathology was essentially normal. However, all patients with suspected nickel allergy showed a significant clinical and functional improvement with excellent short-term survival rates. The clinical significance of a positive LTT needs further study., Competing Interests: T.W.B. reports personal fees from MoxiMed, personal fees from Leica Biosystems, non-financial support from Bio2 Technologies, other from JBJS, other from JBJS Connector, outside the submitted work. P.K.S. reports grants from Intellijoint, personal fees from Lima Corporate, personal fees from DePuy, grants from EOS Imaging, outside the submitted work. G.H.W. reports grants and personal fees from Stryker, grants and personal fees from Exactech, grants from Malinckrodt, outside the submitted work., (Thieme. All rights reserved.)

Background: The extent to which hemoglobinopathies other than sickle anemia (HbSS) are associated with hip osteonecrosis is unknown. Sickle cell trait (HbS), hemoglobin SC (HbSC), and sickle/β-thalassemia (HbSβTh) may also predispose to osteonecrosis of the femoral head (ONFH). We sought to compare the distributions of indications for a total hip arthroplasty (THA) in patients with and without specific hemoglobinopathies., Methods: PearlDiver, an administrative claims database, was used to identify 384,401 patients aged 18 years or older undergoing a THA not for fracture from 2010 to 2020, with patients grouped by diagnosis code (HbSS N = 210, HbSC N = 196, HbSβTh N = 129, HbS N = 356). β-Thalassemia minor (N = 142) acted as a negative control, and patients without hemoglobinopathy as a comparison group (N = 383,368). The proportion of patients with ONFH was compared to patients without it by hemoglobinopathy groups using chi-squared tests before and after matching on age, sex, Elixhauser Comorbidity Index, and tobacco use., Results: The proportion of patients with ONFH as the indication for THA was higher among those with HbSS (59%, P < .001), HbSC (80%, P < .001), HbSβTh (77%, P < .001), and HbS (19%, P < .001) but not with β-thalassemia minor (9%, P  = .6) than the proportion of patients without hemoglobinopathy (8%). After matching, the proportion of patients with ONFH remained higher among those with HbSS (59% vs 21%, P < .001), HbSC (80% vs 34%, P < .001), HbSβTh (77% vs 26%, P < .001), and HbS (19% vs 12%, P < .001)., Conclusions: Hemoglobinopathies beyond sickle cell anemia were strongly associated with having osteonecrosis as the indication for THA. Further research is needed to confirm whether this modifies THA outcomes., (© 2022 The Authors.)

Concerns persist that the Optetrak Logic posterior-stabilized (PS) total knee arthroplasty (TKA) femoral component might correlate with early failures due to aseptic loosening. The primary aim of this study was to examine if the use of the Optetrak Logic PS femoral component is associated with early (<5 years) and more extensive aseptic loosening compared with other PS femoral components. This is a single-institution retrieval analysis and revision registry study (based on prospectively collected data) of 27 failed primary PS TKA patients with loose femoral components that underwent revision TKAs between 2016 and 2019. Patients were stratified by components type: Group A ( n  = 16) received the Optetrak Logic PS femoral component, while Group B ( n  = 11) received other PS femoral components. Burnishing (macroscopic polishing of the component's backside) was observed and graded as a marker for relative motion at the cement-implant interface. No significant differences were found between the two groups regarding the baseline demographic, radiographic, and clinical characteristics. Mean length of implantation for Group A (3.8 ± 2.9 years) was significantly shorter ( p  < 0.001) than that of Group B (12.0 ± 6.7 years). A significant difference ( p  = 0.009) was found in presence of backside femoral burnishing between Group A (15 of 16 patients; 93.8%) and group B (5 of 11 patients; 45.6%). Furthermore, we found a significant difference ( p  < 0.001) in the severity of burnishing between Group A (13 of 16 patients with severe degree of burnishing; 81.3%) and Group B (1 of 11 patients with severe degree of burnishing; 9.1%). In contrast to Group B, a distinctive macroscopic pattern found in Logic retrieved femoral components (Group A) was the total absence of cement in the backside surface. The use of the Optetrak Logic PS TKA femoral component was associated with early aseptic loosening and increased presence and severity of backside burnishing with early cement-implant interface debonding compared with other commercially available types of PS TKA femoral components. The earlier failure rate with this implant is of concern., Competing Interests: None declared., (Thieme. All rights reserved.)

Purpose: Although various papers have reported on the clinical performance of cup retention with cementation of a new liner and bone grafting in the management of well-fixed cups with polyethylene wear and periacetabular osteolysis after total hip arthroplasty (THA), no systematic review of this topic has been published to date., Methods: Medline, EMBASE and Cochrane Library were searched for articles published from January 1999 to January 2019 using "osteolysis" AND "well-fixed", "osteolysis" AND "retro-acetabular", "bone graft" AND ("retention" OR "retained" OR "stable") AND "cup", and "cemented liner" AND "well-fixed"., Results: Nine articles were selected for review (186 cases, 76.1 months mean follow-up). The overall revision rate was 11.3% (21 hips) most commonly due to aseptic loosening (9/186 hips), dislocation (8/186 hips), and liner wear progression (2/186 cases). The reported square size of osteolytic lesions ranged from a mean of 465.84 mm 2 to a max of 4,770 mm 2 . Almost all reported lesions treated with bone grafts resolved or did not progress 97% (72/74). All studies indicated improved pain and functional scores at follow-up., Conclusion: Cementation of a new liner with periacetabular bone grafting provides an alternative option to isolated liner exchange and cup revision for the management of periacetabular osteolysis in well-fixed cups with a disrupted locking mechanism or unavailable exchange liner. Further higher quality studies are required in order to examine if the use of highly cross-linked polyethylene, highly porous-coated cups, hydroxyapatite-coated cups, and small-diameter cups influence the clinical outcome of liner cementation in well-fixed cups with periacetabular osteolysis., (© 2021. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Aims: Although CT is considered the benchmark to measure femoral version, 3D biplanar radiography (hipEOS) has recently emerged as a possible alternative with reduced exposure to ionizing radiation and shorter examination time. The aim of our study was to evaluate femoral stem version in postoperative total hip arthroplasty (THA) patients and compare the accuracy of hipEOS to CT. We hypothesize that there will be no significant difference in calculated femoral stem version measurements between the two imaging methods., Methods: In this study, 45 patients who underwent THA between February 2016 and February 2020 and had both a postoperative CT and EOS scan were included for evaluation. A fellowship-trained musculoskeletal radiologist and radiological technician measured femoral version for CT and 3D EOS, respectively. Comparison of values for each imaging modality were assessed for statistical significance., Results: Comparison of the mean postoperative femoral stem version measurements between CT and 3D hipEOS showed no significant difference (p = 0.862). In addition, the two version measurements were strongly correlated ( r = 0.95; p < 0.001), and the mean paired difference in postoperative femoral version for CT scan and 3D biplanar radiography was -0.09° (95% confidence interval -1.09 to 0.91). Only three stem measurements (6.7%) were considered outliers with a > 5° difference., Conclusion: Our study supports the use of low-dose biplanar radiography for the postoperative assessment of femoral stem version after THA, demonstrating high correlation with CT. We found no significant difference for postoperative femoral version when comparing CT to 3D EOS. We believe 3D EOS is a reliable option to measure postoperative femoral version given its advantages of lower radiation dosage and shorter examination time.Cite this article: Bone Joint J  2022;104-B(11):1196-1201.

Background: Spinopelvic hypermobility may be secondary to a stiff osteoarthritic hip with a compliant spine. Purpose: We sought to determine if spinopelvic hypermobility resolves after total hip arthroplasty (THA) and when it resolves in patients with bilateral hip osteoarthritis (OA) undergoing staged bilateral THA. We also sought to analyze the change in spinopelvic parameters before and after the second THA. Methods: We conducted a retrospective review of 2047 THAs that were performed by 2 fellowship-trained arthroplasty surgeons from 2014 to 2018. Patients with preoperative spinopelvic hypermobility undergoing staged bilateral THA were identified. Radiographic spinopelvic parameters, including sacral slope (SS), pelvic incidence (PI), lumbar lordosis (LL), PI-LL mismatch, anterior pelvic plane tilt (APPt), and spinopelvic tilt (SPT), were measured on preoperative, 6-week postoperative, and 1-year postoperative lateral standing and sitting radiographs. Bilateral hip OA was graded using Kellgren-Lawrence criteria. Results: We identified 42 patients with preoperative spinopelvic hypermobility who underwent staged bilateral THA. Mean time (standard deviation) between surgeries was 9.4 months (±10.0). After the first THA, spinopelvic hypermobility resolved in 29% of the patients. After the second THA, it resolved in 67% at 6 weeks, increasing to 98% at 1 year postoperatively. Conclusion: Spinopelvic hypermobility resolves after staged bilateral THA in 98% of the patients, occurring most often only after the second THA. Less than one-third of the patients had resolution after the first THA, suggesting that contralateral hip OA continues to drive hip-driven spinopelvic motion. Acetabular component position targets based on functional pelvic position should incorporate these changes in spinopelvic motion with the understanding that resolution of hypermobility usually occurs after the second THA., Competing Interests: Declaration of Conflicting Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Eric N. Windsor, MS, declares he has nothing to disclose. Peter K. Sculco, MD, reports relationships with Intellijoint Surgical, Depuy Synthes, and EOS Imaging outside the submitted work. David J. Mayman, MD, reports relationships with Imagen, Insight, Orthalign, Wishbone, and Smith and Nephew outside the submitted work. Jonathan M. Vigdorchik, MD, reports relationships with Corin, Intellijoint Surgical, Medacta, Motion Insights, and Zimmer outside the submitted work. Seth A. Jerabek, MD, reports relationships with Imagen and Stryker outside the submitted work., (© The Author(s) 2021.)

The articular design of a polyethylene insert influences the kinematics and overall function of a total knee arthroplasty (TKA). Standard symmetric posterior-stabilized and cruciate-retaining polyethylene designs have a long track record of high patient satisfaction and longevity in TKA. However, the number and variety of polyethylene inserts and articulations have continued to evolve in an attempt to better replicate native knee kinematics or provide additional constraint. Ultracongruent polyethylene designs have been touted as increasing stability while maintaining the benefits of cruciate-retaining knees. Medial pivot and lateral/dual pivot polyethylene designs were introduced to mimic more normal knee kinematics with regard to femoral rollback. Further, with increasing recognition of knee instability as a cause for persistent symptoms and revision TKA, the utilization of midlevel constraint polyethylene inserts has been increasing, with multiple implant companies offering an insert design with increased constraint for use with a primary femoral component. In this rapidly evolving arena in with a myriad of options available, surgeons should be knowledgeable about the design concepts and their applicable uses for specific patient scenarios. Future research is needed to better understand whether a particular type or design of polyethylene insert and articulation leads to improved patient reported outcomes, improved replication of knee kinematics, and long-term durable implant survivorship., Competing Interests: D.J.M. reports personal fees from Smith & Nephew, OrthoAlign, and other from InSight and Wishbone outside the submitted work. P.K.S. reports personal fees from EOS Imaging, DePuy, Intellijoint Surgical, and from Lima Corporate outside the submitted work. H.J.S. reports personal fees from Lima Corporate, and other from Evolve Ortho outside the submitted work. G.H.W. reports personal fees from Stryker, Exactech, and Mallinckrodt Pharmaceuticals outside the submitted work. S.B.H. reports personal fees from Smith & Nephew, OrthoAlign, Heraeus, and other from OpLogix, outside the submitted work. In addition, S.B.H. has a patent Smith & Nephew Knee Prosthesis with royalties paid.., (Thieme. All rights reserved.)

Aims: Accurate identification of the ankle joint centre is critical for estimating tibial coronal alignment in total knee arthroplasty (TKA). The purpose of the current study was to leverage artificial intelligence (AI) to determine the accuracy and effect of using different radiological anatomical landmarks to quantify mechanical alignment in relation to a traditionally defined radiological ankle centre., Methods: Patients with full-limb radiographs from the Osteoarthritis Initiative were included. A sub-cohort of 250 radiographs were annotated for landmarks relevant to knee alignment and used to train a deep learning (U-Net) workflow for angle calculation on the entire database. The radiological ankle centre was defined as the midpoint of the superior talus edge/tibial plafond. Knee alignment (hip-knee-ankle angle) was compared against 1) midpoint of the most prominent malleoli points, 2) midpoint of the soft-tissue overlying malleoli, and 3) midpoint of the soft-tissue sulcus above the malleoli., Results: A total of 932 bilateral full-limb radiographs (1,864 knees) were measured at a rate of 20.63 seconds/image. The knee alignment using the radiological ankle centre was accurate against ground truth radiologist measurements (inter-class correlation coefficient (ICC) = 0.99 (0.98 to 0.99)). Compared to the radiological ankle centre, the mean midpoint of the malleoli was 2.3 mm (SD 1.3) lateral and 5.2 mm (SD 2.4) distal, shifting alignment by 0.34 o (SD 2.4 o ) valgus, whereas the midpoint of the soft-tissue sulcus was 4.69 mm (SD 3.55) lateral and 32.4 mm (SD 12.4) proximal, shifting alignment by 0.65 o (SD 0.55 o ) valgus. On the intermalleolar line, measuring a point at 46% (SD 2%) of the intermalleolar width from the medial malleoli (2.38 mm medial adjustment from midpoint) resulted in knee alignment identical to using the radiological ankle centre., Conclusion: The current study leveraged AI to create a consistent and objective model that can estimate patient-specific adjustments necessary for optimal landmark usage in extramedullary and computer-guided navigation for tibial coronal alignment to match radiological planning.Cite this article: Bone Jt Open  2022;3(10):767-776.

Background: Outcomes after aseptic revision total hip arthroplasty (THA) are variable, and it is unknown whether the indication for aseptic revision THA influences postoperative clinical improvement. The minimal clinically important difference (MCID) assesses if changes in patient-reported outcome measure result in meaningful clinical benefit to patients. The purpose of this study was to quantify the 1-year postoperative MCID for aseptic revision THA and to assess the percentage of patients achieving the MCID for each revision diagnosis., Methods: A prospective, single-institution registry of revision total joint arthroplasties was used. Retrospective review of 413 first-time aseptic revision THAs was performed. Demographics, revision diagnosis, preoperative Hip Disability and Osteoarthritis Outcome Score, Joint Replacement (HOOS Jr.), and 1-year postoperative HOOS Jr. were recorded. The MCID for the HOOS Jr. at one year postoperatively was calculated for each revision diagnosis using a distribution-based method. The percentage of patients exceeding the MCID with each diagnosis was determined., Results: There were 9 aseptic revision diagnoses, all with n ≥ 5. The 3 most common revision diagnosis were aseptic loosening (n = 114), dislocation or instability (n = 103), and polyethylene wear or osteolysis (n = 73). The MCID for all the aseptic revision THAs was 10.9. Seven of the nine revision diagnoses achieved the MCID. The highest percentage of patients achieving the MCID was for aseptic loosening (84.2%) and implant fracture (81.3%), whereas lowest was for adverse local tissue reaction (35.3%) and implant recall (20.0%)., Conclusion: The one-year revision THA MCID is 10.9 for the HOOS Jr. There is variability in the percentage of patients achieving the MCID based on diagnosis. Our data can be used to counsel patients undergoing revision THA for noninfectious etiologies., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Seeing as there are many alignment strategies for total knee arthroplasty (TKA), we need to determine differences between them in a rigorous scientific way. Therefore, we sought to compare perioperative and postoperative functional outcomes in patients undergoing TKA for varus osteoarthritis with a mechanical alignment target vs a kinematic alignment target, both executed with the same implant and same technological guidance., Methods: One hundred consecutive patients who underwent TKA using a mechanical alignment technique were 1:1 matched to 100 patients who underwent TKA using a kinematic alignment (KA) technique, using the same implant and robotic technology. Patient-reported outcomes were measured postoperatively at 1 and 2 years. Power analysis revealed 94 patients to detect a significant difference., Results: Mean Visual Analog Scale scores were higher in the mechanical alignment group during the first 6 weeks (P = .04), but statistically similar at 1 year. Six-week Veterans RAND 12 Item Health Survey mental and physical components were statistically similar (P = .1). Patients did not differ in 6-week or 1-year knee range of motion (P > .43). Knee Injury and Osteoarthritis Outcome Score Joint Replacement was significantly better in the KA group at 6 weeks, 1 year, and 2 years (P = .09). Forgotten Joint Score at 1 and 2 years postoperatively were significantly higher in the KA group (P < .001)., Conclusion: Patients undergoing TKA with KA experienced less pain in 6 weeks after surgery, and higher Forgotten Joint Scores at 1 and 2 years postoperatively. Alternative TKA alignment and balancing strategies should be considered to increase patient satisfaction., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: In TKA, soft tissue balancing is assessed through manual intraoperative trialing. This assessment is a physical examination via manually applied forces at the ankle, generating varus and valgus moments at the knee while the surgeon visualizes the lateral and medial gaps at the joint line. Based on this examination, important surgical decisions are made that influence knee stability, such as choosing the polyethylene insert thickness. Yet, the applied forces and the assessed gaps in this examination represent a qualitative art that relies on each surgeon's intuition, experience, and training. Therefore, the extent of variation among surgeons in conducting this exam, in terms of applied loads and assessed gaps, is unknown. Moreover, whether variability in the applied loads yields different surgical decisions, such as choice of insert thickness, is also unclear. Thus, surgeons and developers have no basis for deciding to what extent the applied loads need to be standardized and controlled during a knee balance exam in TKA., Questions/purposes: (1) Do the applied moments in soft tissue assessment differ among surgeons? (2) Do the assessed gaps in soft tissue assessment differ among surgeons? (3) Is the choice of insert thickness associated with the applied moments?, Methods: Seven independent human cadaveric nonarthritic lower extremities from pelvis to toe were acquired (including five females and two males with a mean age of 73 ± 7 years and a mean BMI of 25.8 ± 3.8 kg/m 2 ). Posterior cruciate ligament substituting (posterior stabilized) TKA was performed only on the right knees. Five fellowship-trained knee surgeons (with 24, 15, 15, 7, and 6 years of clinical experience) and one chief orthopaedic resident independently examined soft tissue balance in each knee in extension (0° of flexion), midflexion (30° of flexion), and flexion (90° of flexion) and selected a polyethylene insert based on their assessment. Pliable force sensors were wrapped around the leg to measure the loads applied by each surgeon. A three-dimensional (3D) motion capture system was used to measure knee kinematics and a dynamic analysis software was used to estimate the medial and lateral gaps. We assessed (1) whether surgeons applied different moments by comparing the mean applied moment by surgeons in extension, midflexion, and flexion using repeated measures (RM)-ANOVA (p < 0.05 was assumed significantly different); (2) whether surgeons assessed different gaps by comparing the mean medial and lateral gaps in extension, midflexion, and flexion using RM-ANOVA (p < 0.05 was assumed significantly different); and (3) whether the applied moments in extension, midflexion, and flexion were associated with the insert thickness choice using a generalized estimating equation (p < 0.05 was assumed a significant association)., Results: The applied moments differed among surgeons, with the largest mean differences occurring in varus in midflexion (16.5 Nm; p = 0.02) and flexion (7.9 Nm; p < 0.001). The measured gaps differed among surgeons at all flexion angles, with the largest mean difference occurring in flexion (1.1 ± 0.4 mm; p < 0.001). In all knees except one, the choice of insert thickness varied by l mm among surgeons. The choice of insert thickness was weakly associated with the applied moments in varus (β = -0.06 ± 0.02 [95% confidence interval -0.11 to -0.01]; p = 0.03) and valgus (β = -0.09 ± 0.03 [95% CI -0.18 to -0.01]; p= 0.03) in extension and in varus in flexion (β = -0.11 ± 0.04 [95% CI -0.22 to 0.00]; p = 0.04). To put our findings in context, the greatest regression coefficient (β = -0.11) indicates that for every 9-Nm increase in the applied varus moment (that is, 22 N of force applied to the foot assuming a shank length of 0.4 m), the choice of insert thickness decreased by 1 mm., Conclusion: In TKA soft tissue assessment in a human cadaver model, five surgeons and one chief resident applied different moments in midflexion and flexion and targeted different gaps in extension, midflexion, and flexion. A weak association between the applied moments in extension and flexion and the insert choice was observed. Our results indicate that in the manual assessment of soft tissue, changes in the applied moments of 9 and 11 Nm (22 to 27 N on the surgeons' hands) in flexion and extension, respectively, yielded at least a 1-mm change in choice of insert thickness. The choice of insert thickness may be more sensitive to the applied moments in in vivo surgery because the surgeon is allowed a greater array of choices beyond insert thickness., Clinical Relevance: Among five arthroplasty surgeons with different levels of experience and a chief resident, subjective soft tissue assessment yielded 1 to 2 mm of variation in their choice of insert thickness. Therefore, developers of tools to standardize soft tissue assessment in TKA should consider controlling the force applied by the surgeon to better control for variations in insert selection., Competing Interests: All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request., (Copyright © 2022 by the Association of Bone and Joint Surgeons.)

Background: An extended trochanteric osteotomy (ETO) safely addresses femoral component removal during challenging revision total hip arthroplasty. However, no prior study has evaluated whether a difference in axial stability exists between ETO closure performed before (reconstitution) or after (scaffolding) canal preparation and stem impaction. We hypothesized that given the absence of clinical reports of outcome differences despite the wide use of both practices, no significant difference in the initial axial stability would exist between the 2 fixation techniques., Methods: ETOs were performed and repaired using the reconstitution technique for the 6 right-sided femora and the scaffolding technique for the six left-sided femora. The 195-mm long, 3.5°-tapered splined titanium monobloc stems were impacted into 6 matched pairs of human fresh cadaveric femora. Three beaded cables were placed in a standardized fashion on each specimen, 1 for prophylaxis against osteotomy propagation during reaming/impaction and 2 to close the ETO. Stepwise axial loading was performed to 2600 N or until failure, which was defined as subsidence >5 mm or femoral/cable fracture., Results: All specimens successfully resisted axial testing, with no stem in either ETO repair group subsiding >2 mm. The mean subsidence for the reconstitution group was 0.9 ± 0.4 mm, compared to 1.2 ± 0.5 mm for the scaffolding group (P = .2)., Conclusion: In this cadaveric model with satisfactory proximal bone stock, no difference existed between the reconstitution and scaffolding ETO repair techniques, and both provide sufficient immediate axial stability in a simulated revision total hip arthroplasty setting under physiologic loads., (Copyright © 2021 Elsevier Inc. All rights reserved.)

Background: Several commonly prescribed medications have known antifibrotic properties and have been shown to reduce postoperative scar formation in other clinical areas, but it is unknown whether the use of such medications perioperatively in patients undergoing TKA may improve rates of postoperative stiffness., Methods: A large US employer-sponsored healthcare database (Truven Marketscan) was queried for patients who underwent elective primary TKA for primary osteoarthritis between 2015-2019. Demographic information and comorbidities were recorded, along with whether patients were prescribed one of several medications with known antifibrotic properties during the three months before or after surgery., Results: Complete data were available for 101,366 patients undergoing TKA, of which 4,536 underwent MUA (4.5%). Perioperative use of any antifibrotic medication was associated with a lower likelihood of undergoing MUA (P < .001). When controlling for age, sex, comorbidities, opioid use, length of stay, among other variables, perioperative use of specific ACE inhibitors (OR 0.91, CI 0.84-1, P = .042), COX-2 inhibitors (OR 0.88, CI 0.81-0.96, P = .002), and angiotensin II receptor blockers, specifically losartan (OR 0.80, CI 0.70-0.91, P = .007) all remained significantly associated with lower rates of MUA., Conclusion: This study, spanning over a hundred thousand primary TKA procedures over a recent five-year period, demonstrates an association between perioperative use of specific medications with antifibrotic properties and a decreased rate of MUA. These data will help inform future studies aimed to prospectively evaluate the potential of antifibrotic medications in preventing postoperative stiffness in high-risk patients undergoing knee arthroplasty., (Copyright © 2022 Elsevier Inc. All rights reserved.)

A subset of patients undergoing total knee arthroplasty (TKA) for knee osteoarthritis develop debilitating knee stiffness (reduced range of motion) for poorly understood reasons. Dysregulated inflammatory and immune responses to surgery correlate with reduced surgical outcomes, but the dysregulated gene signatures in patients with stiffness after TKA are poorly defined. As a consequence, we are limited in our ability to identify patients at risk of developing poor surgical outcomes and develop preventative approaches. In this pilot study we aimed to identify perioperative blood gene signatures in patients undergoing TKA for knee osteoarthritis and its association with early surgical outcomes, specifically knee range of motion. To do this, we integrated clinical outcomes collected at 6 weeks after surgery with transcriptomics analyses in blood samples collected immediately before surgery and at 24 h after surgery. We found that patients with stiffness at 6 weeks after surgery have a more variable and attenuated circulating gene expression response immediately after surgery. Our results suggest that patients with stiffness following TKA may have distinct gene expression signatures detectable in peripheral blood in the immediate postoperative period., (© 2022. The Author(s).)

Background: Computer-assisted surgery that does not utilize femoral canal instrumentation is theorized to have less blood loss. However, there is a paucity of data on this, particularly in the era of tranexamic acid use. We sought to analyze the association of computer navigation with total calculated blood loss and transfusion rate in patients undergoing primary total knee arthroplasty (TKA)., Methods: We identified 14,890 patients who underwent unilateral primary TKA at a single institution from 2016 to 2020. Computer-assisted surgery in the form of an accelerometer or robotics was utilized in 4,165 TKAs (28%). Drains were utilized in 4,860 TKAs (32%). We used multivariate logistic regression analysis to determine if computer navigation reduced the rate of blood transfusion and linear regression analysis to determine the impact of computer navigation on blood loss., Results: In total, 542 patients (3.6%) underwent a transfusion. The average change in hemoglobin (Hgb) was 2.1 g/dL (standard deviation [SD] 0.91) and average total calculated blood loss was 310 mL (SD = 154). In a multivariate regression model, computer navigation was not protective of transfusion (odds ratio [OR] 1.04, P = .73). Preoperative Hgb <10 (OR 10.5, P < .0001) and drain use (OR 2.25, P < .0001) were the most significant risk factors for transfusion. In a linear regression model, computer navigation reduced blood loss by 19 mL (SD 2.94, P < .0001) per case., Conclusion: In this large retrospective cohort analysis of contemporary TKA patients, computer-assisted surgery that eliminates intramedullary femoral canal instrumentation during primary TKA was not associated with reduced transfusion rates and had minimal differences in overall blood loss., (Copyright © 2022 Elsevier Inc. All rights reserved.)