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Denosumab is a monoclonal antibody used to reduce risk of fractures in osteoporosis. ROSALIA was a multicenter, double-blind, randomized, integrated phase I/phase III study comparing the efficacy, pharmacokinetics (PK), pharmacodynamics (PD), immunogenicity, and safety of proposed biosimilar denosumab GP2411 with reference denosumab (REF-DMAb) (Prolia®; Amgen). Postmenopausal women with osteoporosis were randomized 1:1 to 2 60-mg doses of GP2411 or REF-DMAb, one at study start and one at week 26. At week 52, the REF-DMAb group was re-randomized 1:1 to a third dose of REF-DMAb or switch to GP2411. The primary efficacy endpoint was percentage change from baseline (%CfB) in LS-BMD at week 52. Secondary efficacy endpoints were %CfB in LS-BMD, FN-BMD, and TH-BMD at weeks 26 and 78 (and week 52 for FN-BMD and TH-BMD). Primary PK and PD endpoints were the area under the serum concentration-time curve extrapolated to infinity and maximum drug serum concentration at week 26, and the area under the effect-time curve of the %CfB in serum CTX at week 26. Secondary PK and PD endpoints included drug serum concentrations and %CfB in serum CTX and P1NP during the study period. Similar efficacy was demonstrated at week 52, with 95% CIs of the difference in %CfB in LS-BMD between treatment groups fully contained within prespecified equivalence margins. Similarity in PK and PD was demonstrated at week 26. Immunogenicity was similar between groups and was not impacted by treatment switch. The rate of new vertebral fractures was comparable. Treatment-emergent adverse events were comparable between groups (63.6% [GP2411/GP2411]; 76.0% [REF-DMAb/REF-DMAb]; 76.6% [REF-DMAb/GP2411]). In conclusion, ROSALIA showed similar efficacy, PK and PD, and comparable safety and immunogenicity of GP2411 to REF-DMAb in postmenopausal osteoporosis., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Society for Bone and Mineral Research.)

Characterizing cellular diversity at different levels of biological organization and across data modalities is a prerequisite to understanding the function of cell types in the brain. Classification of neurons is also essential to manipulate cell types in controlled ways and to understand their variation and vulnerability in brain disorders. The BRAIN Initiative Cell Census Network (BICCN) is an integrated network of data-generating centers, data archives, and data standards developers, with the goal of systematic multimodal brain cell type profiling and characterization. Emphasis of the BICCN is on the whole mouse brain with demonstration of prototype feasibility for human and nonhuman primate (NHP) brains. Here, we provide a guide to the cellular and spatial approaches employed by the BICCN, and to accessing and using these data and extensive resources, including the BRAIN Cell Data Center (BCDC), which serves to manage and integrate data across the ecosystem. We illustrate the power of the BICCN data ecosystem through vignettes highlighting several BICCN analysis and visualization tools. Finally, we present emerging standards that have been developed or adopted toward Findable, Accessible, Interoperable, and Reusable (FAIR) neuroscience. The combined BICCN ecosystem provides a comprehensive resource for the exploration and analysis of cell types in the brain., Competing Interests: I have read the journal’s policy and the authors of this manuscript have the following competing interests: AR is a co-founder and equity holder of Celsius Therapeutics, an equity holder in Immunitas Therapeutics and, until 31 July 2020, was a scientific advisory board member of Thermo Fisher Scientific, Syros Pharmaceuticals, Asimov, and Neogene Therapeutics. From 1 August 2020, AR is an employee of Genentech and has equity in Roche. AR is a named inventor on multiple patents related to single cell and spatial genomics filed by or issued to the Broad Institute., (Copyright: © 2023 Hawrylycz et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Background: Multimodal analgesia has become the standard of care for pain management following total knee arthroplasty (TKA). Cannabidiol (CBD) is increasingly utilized in the postoperative period. The purpose of this study was to analyze the analgesic benefits of topical CBD following primary TKA., Methods: In this randomized double-blinded placebo-controlled trial, 80 patients undergoing primary unilateral TKA applied topical CBD (CBD; n = 19), essential oil (EO; n = 21), CBD and essential oil (CBD + EO; n = 21), or placebo (PLA; n = 19) thrice daily around the knee for two weeks postoperatively. This supplemented a standardized multimodal analgesic protocol. Outcomes included visual analog scale (VAS) pain and numeric rating scale (NRS) sleep scores (collected on postoperative day [POD] 0, 1, 2, 7, 14, 42), and cumulative postoperative opioid use (42 days)., Results: Demographic characteristics were similar among the four cohorts. Preoperative VAS and NRS scores were similar among groups. The CBD cohort had a higher mean VAS pain score on POD 2 compared to the EO cohort (CBD: 69.9 ± 19.3 versus. EO: 51.0 ± 18.2; P = .013). No statistically significant differences existed for VAS scores at other times, and no statistically significant differences were observed for postoperative NRS sleep scores or postoperative opioid use at any time point., Conclusion: Utilization of topical CBD in supplement to multimodal analgesia did not reduce pain or opioid consumption, or improve sleep scores following TKA. These results suggest that the local effects of topical CBD are not beneficial for providing additional pain relief after TKA., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Both cones or sleeves have been developed to address metaphyseal bone loss in revision total knee arthroplasty (TKA), but few studies have directly compared the outcomes. The purpose of this study was to compare the survivorship and aseptic revision rates between metaphyseal cones and sleeves at intermediate follow-up., Methods: We reviewed a consecutive series of 1,172 revision TKA patients between 2009 and 2018 with a minimum two-year follow-up on all patients. We compared demographics, surgical indication, stem fixation, constraint, rates of rerevision, and Short-Form-12 scores between patients with cones and sleeves. A multivariate analysis was performed to identify the effect of cones and sleeves on aseptic rerevision. Kaplan-Meier curves were generated to compare aseptic survivorship of cones and sleeves., Results: There were 194 tibial cones (17%), 107 tibial sleeves (9%), 31 femoral cones (3%), and 135 femoral sleeves (12%) with a mean follow-up of 6.5 years (range: 2-12 years). There was no difference in demographics, indication, stem fixation, or constraint (P > .05). Although overall aseptic failure rates may be lower for tibial sleeves, there were no significant differences in survivorship over a one-year, two-year, and five-year follow-up when both tibial and femoral sleeves were directly compared to cones., Conclusion: Both tibial and femoral sleeves and cones perform well at an intermediate-term follow-up. Further investigation of these two are required to better understand their survivorship relative to each other., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Progressive arthritis in the unresurfaced compartments of the knee is one failure mode after partial knee arthroplasty (PKA). While progressive arthritis after PKA is typically treated with revision to TKA (rTKA), staged bicompartmental knee arthroplasty (sBiKA) -the addition of another PKA - is an alternative. This study compared outcomes of sBiKA and rTKA for progressive arthritis after PKA., Methods: A retrospective comparative study of non-consecutive cases at four institutions were performed in patients with an intact PKA, without loosening or wear, who underwent sBiKA (n = 27) or rTKA (n = 30), for progressive osteoarthritis. Outcomes studied were new Knee Society Function and Objective Scores (KSSF, KSSO), KOOS, Jr., ROM, operative times, length of stay, complication rates and the need for reoperations., Results: Mean time to conversion was 7.4 ± 6 years for sBiKA and 9.7 ± 8 for rTKA, P = .178. Patient demographics and pre-operative outcomes were similar among cohorts. At an average of 5.7 ± 3 (sBiKA) and 3.2 ± 2 years (rTKA), KOOS, Jr. significantly improved, P < .001, by an equivalent amount. Post-operative KSSO and KSSF were significantly higher in the sBiKA cohort, respectively, (90.4 ± 10 vs 72.1 ± 20, P < .001) and (80.3 ± 18 vs 67.1 ± 19, P = .011). sBiKA patients had significantly greater improvement in KSSO (30.7 ± 33 vs 5.2 ± 18, P = .003). One sBiKA patient underwent reoperation for continued pain., Conclusion: SBiKA has equivalent survivorship, but greater improvement in functional outcomes as rTKA at short to midterm follow-up. Given the shorter operative times and length of stay, sBiKA is a safe and cost-effective alternative to rTKA for progressive osteoarthritis following PKA. Nevertheless, further follow-up is necessary to determine whether sBiKA is a durable option., (Copyright © 2022 Elsevier Inc. All rights reserved.)

Background: Both modular and monoblock tapered fluted titanium (TFT) stems have gained popularity over fully porous-coated cylindrical (FPCC) femoral stem designs, but limited data exist comparing subsidence rates following revision total hip arthroplasty (THA). The purpose of this study is to determine differences in subsidence and clinical outcomes among 3 revision femoral stem designs., Methods: We reviewed a consecutive series of 335 patients who underwent femoral component revision to a cementless modular TFT (n = 225), monoblock TFT (n = 63), or FPCC (n = 47) stem between 2012 and 2019. We evaluated radiographic subsidence rates, re-revision rates, and patient-reported outcomes between the 3 stems. A multivariate regression analysis was performed to determine the independent effect of stem type on the risk of subsidence >5 mm., Results: At an average follow-up of 39 months (range, 12 to 96 months), there were no differences in mean subsidence rates (3.5 vs 2.4 vs 2.1 mm, P = .14), HOOS Jr scores (78 vs 74 vs 64 points, P = .15), or aseptic re-revision rates (4% vs 3% vs 0%, P = .29) between modular TFT, monoblock TFT, and FPCC stems. Although modular TFT stems were more often used in patients with extensive femoral bone loss (Paprosky III and IV), there were no differences in subsidence rates >5 mm among the 3 stems (P > .05) in multivariate analysis., Conclusion: Modular TFT, monoblock TFT, and FPCC femoral stem designs all perform well in revision THA with no difference in clinical outcomes or subsidence rates. Surgeons should select the stem which they feel is the most clinically appropriate., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Understanding of neuronal circuitry at cellular resolution within the brain has relied on neuron tracing methods which involve careful observation and interpretation by experienced neuroscientists. With recent developments in imaging and digitization, this approach is no longer feasible with the large scale (terabyte to petabyte range) images. Machine learning based techniques, using deep networks, provide an efficient alternative to the problem. However, these methods rely on very large volumes of annotated images for training and have error rates that are too high for scientific data analysis, and thus requires a significant volume of human-in-the-loop proofreading. Here we introduce a hybrid architecture combining prior structure in the form of topological data analysis methods, based on discrete Morse theory, with the best-in-class deep-net architectures for the neuronal connectivity analysis. We show significant performance gains using our hybrid architecture on detection of topological structure (e.g. connectivity of neuronal processes and local intensity maxima on axons corresponding to synaptic swellings) with precision/recall close to 90% compared with human observers. We have adapted our architecture to a high performance pipeline capable of semantic segmentation of light microscopic whole-brain image data into a hierarchy of neuronal compartments. We expect that the hybrid architecture incorporating discrete Morse techniques into deep nets will generalize to other data domains.

Background: Computerized adaptive test (CAT) questionnaires may allow standardization of patient-reported outcome measures and reductions in questionnaire burden. We evaluated the validity, accuracy, and efficacy of a CAT system in patients with end-stage osteoarthritis undergoing total knee arthroplasty., Methods: CAT Knee Osteoarthritis Outcome Scores (KOOS) and CAT KOOS-JR questionnaires were applied to 1871 standard form KOOS and 1493 KOOS-JR patient responses, respectively. Mean, standard deviations, Pearson's correlation coefficients, interclass correlation coefficients (ICCs), frequency distribution plots, and Bland-Altman plots were used to compare the precision, validity, and accuracy between CAT scores and full-form scores., Results: There was a mean reduction of 14 questions (33%) in the CAT KOOS and 1.4 questions (20%) with the CAT KOOS-JR version, compared with the standard KOOS and KOOS-JR surveys, respectively. There were no significant differences between KOOS and CAT KOOS scores with respect to pain (P = .66), symptoms (P = .43), quality of life (P = .99), activities of daily living (P = .68), and sports (P = .84). Similarly, there were no significant differences between the standard form KOOS-JR and CAT KOOS-JR scores (P = .94). There were strong correlations with minimal variability between the CAT KOOS and standard KOOS questionnaires for pain (r = 0.98, ICC: 0.98), symptoms (r = 0.97, ICC: 0.97), quality of life scores (r = 0.99, ICC: 0.99), activities of daily living scores (r = 0.99, ICC: 0.99), and sports scores (r = 0.99, ICC: 0.99). Similarly, there were strong correlations between the KOOS-JR and the CAT KOOS-JR scores (r = 0.99, ICC: 0.99)., Conclusion: CAT KOOS and the CAT KOOS-JR versions are accurate and reduce questionnaire burden up to one-third compared with standard surveys. CAT versions may improve patient compliance and decrease fatigue., (Copyright © 2020 Elsevier Inc. All rights reserved.)

Background: Probability-based computer algorithms that reduce patient burden are currently in high demand. These computer adaptive testing (CAT) methods improve workflow and reduce patient frustration, while achieving high measurement precision. In this study, we evaluated the accuracy and validity of the CAT Hip Disability and Osteoarthritis Outcome Score (HOOS) and the Hip Disability and Osteoarthritis Outcome Score Joint Replacement (HOOS-JR) by comparing them to the full version of these scoring systems in a subset of patients who had undergone total hip arthroplasties., Methods: A previously developed CAT HOOS and HOOS-JR was applied to 354 and 1547 HOOS and HOOS-JR patient responses, respectively. Mean, standard deviations, Pearson's correlation coefficients, interclass correlation coefficients, frequency distribution plots, and Bland-Altman plots were used to compare the precision, validity, and accuracy between CAT scores and full-form scores., Results: By modifying the questions to past responses, the CAT HOOS demonstrated a mean reduction of 30% of questions (28 vs 40 questions). There were no significant differences between the full HOOS and CAT HOOS with respect to pain (P = .73), symptoms (P = .94), quality of life (P = .99), activities of daily living (P = .82), and sports (P = .99). There were strong linear relationships between the CAT versions and the standard questionnaires (r > 0.99). The Bland-Altman plot showed that differences between CAT HOOS and full HOOS were independent of the overall scores., Conclusion: The CAT HOOS and HOOS-JR have high correlation and require fewer questions to finish compared to the standard full-form questionnaires. This may represent a reliable and practical alternative that may be less burdensome to patients and may help improve compliance for reporting outcome metrics., (Copyright © 2019 Elsevier Inc. All rights reserved.)

Introduction: There is paucity of literature evaluating anterior acetabular retractor proximity to the femoral nerve and external iliac vessels during total hip arthroplasty through the direct anterior approach. In this cadaveric study, we evaluated three retractor locations to identify optimal positioning of anterior retractors., Methods: A direct anterior approach was performed in 22 hips of 15 cadavers. Anterior acetabular retractors were placed over the anterior acetabular wall in-line with the femoral neck (12-o'clock or middle position). The anterior neurovascular structures were identified through the ilioinguinal approach. Retractors were reinserted at 10-o'clock (right hip; superior) and 2-o'clock (right hip; inferior) locations marked using K-wires. Horizontal and vertical distances from retractor tip positions to neurovascular structures were measured with a digital caliper., Results: Retractor tips moved significantly from lateral to the femoral nerve when placed in the superior position (mean, 2.8 mm) to medial to the femoral nerve in the middle (mean, -2.3 mm) and inferior (mean, -4.8 mm) locations. Retractor tips moved significantly medial toward the external iliac artery when retractors were moved from superior (mean, 15.3 mm) to inferior (mean, 6.6 mm) positions placing the retractor tip closer to the vessels., Conclusion: As retractor placements moved inferior, retractor tips moved medial to neurovascular structures. Inferior retractor positioning placed the femoral nerve and external iliac artery at the risk of injury during the initial retractor placement or adjustment. Retractors should be placed in a relative safe zone superior to the 12-o'clock position to avoid damage to neurovascular structures., Level of Evidence: IV.

Introduction: Historically, patients with rotator cuff arthropathy had limited reconstructive options. The early generations of reverse total shoulder arthroplasty (rTSA) designs had increased failure rates due to loosening of glenoid baseplates secondary to excessive torques. In 1985, Paul Grammont introduced a prosthetic design changing the center of rotation that addressed this major complication. The Grammont principles remain the foundation of modern reverse total shoulder prostheses, although the original design has undergone several adaptations. We reviewed here the various aspects of prosthetic designs including baseplates, glenospheres, humeral components, and polyethylene bearing interfaces., Areas Covered: We discuss the evolution, biomechanics, prosthetic options, and future direction for rTSA. A literature search using the PubMed database including review articles, biomechanical studies, and clinical trials pertaining to rTSA prothesis and outcomes., Expert Commentary: Despite an expansion in the understanding of the biomechanics of the rotator cuff deficient shoulder and its effect on the reverse total shoulder prostheses, Grammont principles remain the foundation of contemporary rTSA designs. Further clinical studies are needed to assess how modern prosthetic modifications effect clinical and radiographic outcomes. Additionally, implants are being used in younger individuals with expanded indications, therefore, close clinical monitoring is needed to better evaluate their prosthetic longevity.

Wound management is a notable healthcare and financial burden, accounting for >$10 billion in annual healthcare spending in the United States. A multidisciplinary approach involving orthopaedic and plastic surgeons, wound care nursing, and medical and support staff is often necessary to improve outcomes. Orthopaedic surgeons must be familiar with the fundamental principles and evidenced-based concepts for the management of acute and chronic wounds. Knowledge of surgical dressings, negative pressure wound therapy, tissue expanders, dermal apposition, biologics, and extracellular matrices can aide practitioners in optimizing wound care.

Network meta-analysis uses direct comparisons of interventions within randomized controlled trials and indirect comparisons across them. Network meta-analysis uses more data than a series of direct comparisons with placebo, and theoretically should produce more reliable results. We used a Cochrane overview review of acute postoperative pain trials and other systematic reviews to provide data to test this hypothesis. Some 261 trials published between 1966 and 2016 included 39,753 patients examining 52 active drug and dose combinations (27,726 given active drug and 12,027 placebo), in any type of surgery (72% dental). Most trials were small; 42% of patients were in trials with arms <50 patients, and 27% in trials with arms ≥100 patients. Response to placebo in third molar extraction fell by half in studies over 30 to 40 years (171 trials, 7882 patients given placebo). Network meta-analysis and Cochrane analyses provided very similar results (average difference 0.04 number needed to treat units), with no significant difference for almost all comparisons apart from some with small patient numbers or small effect size, or both. Network meta-analysis did not detect significant differences between effective analgesics. The similarity between network meta-analysis and Cochrane indirect analyses probably arose from stringent quality criteria in trials accepted in Cochrane reviews (with consequent low risk of bias) and consistency in methods and outcomes. Network meta-analysis is a useful analytical tool that increases our confidence in estimates of efficacy of analgesics in acute postoperative pain, in this case by providing similar results.

Introduction: Acute traumatic or surgical wounds that cannot be primarily closed often cause substantial morbidity and mortality. This often leads to increased costs from higher material expenses, more involved nursing care, and longer hospital stays. Advancements in soft tissue expansion has made it a popular alternative to facilitate early closure without the need for more complicated plastic surgical procedures., Areas Covered: In this review, we briefly elaborate on the history and biomechanics of tissue expansion and provide comprehensive descriptions of traditional internal tissue expanders and a variety of contemporary external tissue expanders. We describe their uses, advantages, disadvantages, and clinical outcomes. The majority of articles reviewed include case series with level IV evidence. Outcome data was collected for studies after 1990 using PubMed database., Expert Commentary: An overall reduction in cost, time-to-wound closure, hospital length-of-stay, and infection rate may be expected with most tissue expanders. However, further studies comparing outcomes and cost-effectiveness of various expanders may be beneficial. Surgeons should be aware of the wide array of tissue expanders that are commercially available to individualize treatment based on thorough understanding of their advantages and disadvantages to optimize outcomes. We predict the use of external expanders to increase in the future and the need for more invasive procedures such as flaps to decrease.

Isolated blastomycosis hand infections are extremely rare, and are often clinically unsuspected, leading to delays in clinical diagnosis. Conclusive diagnosis often necessitates fungal cultures and histopathological demonstration of budding yeasts in tissues. In this report, we describe the rare occurrence of isolated blastomycotic hand infection, without any other organ involvement, in a 42-year-old male patient. Analyzing tissue specimens with frozen section has been shown in the past to demonstrate granulomatous inflammation and yeast forms of the organism; however, as demonstrated in this patient, the presence of pseudoepitheliomatous cells may deceptively appear as malignant, causing substantial concern and anxiety. Definitive diagnosis often necessitates fungal culture and histopathological examination with special fungal stains including polymerase chain reaction for speciation., (Copyright © 2017 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.)

Although prosthetic hip dislocation is a common reason for revision arthroplasty, few studies have comprehensively evaluated the radiographic factors that may lead to the need for revision. Therefore, the authors radiographically evaluated all prosthetic hip dislocations that were treated at one institution. They then specifically assessed those that required revision surgery. The authors found that the prosthetic center of rotation (pCOR) was located superolateral and inferolateral to the native COR (nCOR) in all patients. Most hips had pCOR distances more than 5 mm from the nCOR. Furthermore, most patients had cup inclination and anteversion angles within Lewinnek's previously defined "safe zone." Determining these similarities and properly planning these procedures may help decrease the instability rate and therefore improve the overall success of this procedure. [Orthopedics.2016; 39(5):e1011-e1018.]., (Copyright 2016, SLACK Incorporated.)

Background: Periprosthetic infections after total hip arthroplasty represent an increased risk for patient morbidity and mortality, and an increased economic burden. The purpose of this study was to compare a group of patients who had periprosthetic infections after total hip arthroplasty to a matched group of patients who underwent primary total hip arthroplasty in terms of the associated costs, length of hospitalization, and number of readmissions (within 1 year)., Methods: Between 2007 and 2011, 16 consecutive infected patients were matched to 32 noninfected patients (1:2 ratio)., Results: The mean episode cost, length of hospitalization, and median readmissions was significantly higher in the infected group when compared to the matched cohort: $88,623 vs $25,659, 7.6 vs 3.29 days, and 2 vs 0, respectively., Conclusion: Periprosthetic infections after THA resulted in an increased episode cost by approximately 3-fold, mean hospitalization period 2-fold, and led to a higher median number of readmissions., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Prosthetic joint infection is one of the most dreaded complications following elective lower extremity primary total joint arthroplasty, resulting in substantial pain, disability, and health care costs. Both static and articulating antibiotic-impregnated spacers have been used in the management of 2-stage revision for infected total knee arthroplasty, which remains the gold standard for treatment of these infections. Articulating spacers may provide theoretical benefits with regard to improved range of motion after reimplantation secondary to less scar formations and soft tissue contractures. However, static spacers may be necessary to overcome instability associated with substantial bone defects, incompetent extensor mechanisms, and collateral ligament insufficiencies. In these scenarios, static spacers are often reinforced with intramedullary rods or Steinmann pins to provide additional knee stability, improve construct strength, maintain extension, and avoid flexion contractures. This case report describes an extremely rare case of migration of smooth pins through the posterior tibia into the calf following static spacer use in a 48-year-old man. Various mechanical and systemic complications have been reported in up to 50% of patients with the use of polymethyl methacrylate spacer devices, such as acute renal failure, allergic reactions from antibiotic use, stiffness, bone loss, fractures, and dislocations. However, to the best of the authors' knowledge, this complication of hardware migration has not been reported previously in the literature. The authors believe that orthopedic surgeons should consider the use of threaded pin dowels or intramedullary rods to avoid this potential untoward complication. [Orthopedics. 2016; 39(3):e553-e557.]., (Copyright 2016, SLACK Incorporated.)

Rotator cuff injuries in the pediatric and adolescent population are rare. These injuries are normally caused by an acute event or by repeated microtrauma as a result of poor mechanics during overhead sporting activities. Overall, these injuries account for fewer than 1% of all rotator cuff tears. Physeal injuries, tuberosity avulsions ("rotator cuff equivalents"), and proximal humeral fractures commonly occur in the pediatric population. Traumatic full-thickness rotator cuff ruptures that occur in this age group during contact sports are an extremely uncommon cause of shoulder pain. The rarity of this type of injury in the pediatric and adolescent population may be the result of the excellent tensile properties of rotator tendons in childhood that often resist mechanical forces better than the growth plate or the apophyses. This report describes a full-thickness rotator cuff tear and a posterior labral tear in a 12-year-old boy who had a direct injury to the shoulder while playing football. The authors' goal in reporting this case is to increase orthopedic surgeons' awareness of this type of injury. Early use of magnetic resonance imaging for persistent shoulder pain after direct injury during contact sports may avoid undue delay in diagnosis. This report also describes the mini-open transosseous extraphyseal technique of cuff repair and reviews the literature on this infrequent injury. Overall, excellent clinical outcomes and return to sports can be expected after surgical repair of torn and often retracted tendons., (Copyright 2016, SLACK Incorporated.)

Intra-articular injections of corticosteroids have been used as a treatment option for degenerative arthritis of the knee for short- to mid-term symptomatic pain relief for many decades. Recently, there have been studies that have reported increased risks of periprosthetic joint infections in patients who have received these injections. In this study, we evaluated the risk of superficial, deep, and overall rate of infections in 302 patients who had received intra-articular corticosteroid infiltration within 12 months before undergoing total knee arthroplasty (TKA) and compared them with a 1:1 matched cohort who had undergone TKA, but who did not have any prior corticosteroid knee injections. At a mean follow-up of approximately 3.5 years after TKA, there were no significant differences in the rate of superficial incisional infections (7 vs. 6 out of 302 patients), deep periprosthetic infections (3 vs. 6 out of 302 patients), and overall infections (10 vs. 12 out of 302 patients) in the two groups. In addition, no significant differences were found in the rate of deep infections when intra-articular corticosteroids were administered 10 weeks to 2 months, 2-4 months, 4-6 months, 6-12 months, and beyond 12 months before surgery. We concluded that intra-articular corticosteroid injections are safe and do not increase the rate of postoperative infections.

Precise and accurate biomechanical reconstruction during total hip arthroplasty (THA) is essential for durable long-term survivorship. Accurate fit of cementless hip implants is also crucial to reduce micromotion between the bone-implant interfaces to allow for stable osseointegration. Robotic technology aims to minimize potential human errors and improve implant alignment and fit, and address persisting concerns with modern-day cementless THA. Although robotic THA dates back to the early 1990s, concerns with increased operating times, costs, and complications led to its withdrawal. However, semi-active systems have renewed interest in robot-assisted joint arthroplasty. We reviewed the current technology, its potential benefits, and the reported clinical and radiographic outcomes. Early evidence suggests that robotic use may lead to more accurate reconstruction of radiographic parameters, such as implant positioning, fit, center-of-rotation, and leg-length discrepancy. Further research is needed to determine if these will translate into better outcomes and improved implant longevity to justify increased costs.

This study assessed gross and histopathological ACL changes in arthritic knees (n=174) undergoing total knee arthroplasty. Histopathological changes were assessed and graded as absent (0), mild (1), moderate (2), or marked (3). These were correlated to demographic and clinical factors, and radiographic evaluations. The ACL was intact in 43, frayed in 85, torn in 15, and absent in 31 knees. Eighty-five percent had histological changes. Overall, there were significant associations between greater age and BMI, and histological changes. Grade IV knees had significantly greater calcium pyrophosphate deposits, microcyst formation, and number of pathologic changes. These correlations may aid decision-making when determining suitability for unicompartmental or bicruciate-retaining arthroplasties, though further studies should correlate these histological findings to mechanical and functional knee status., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Degenerative lumbar spinal stenosis (LSS) is a cause for substantial morbidity in the elderly population: many often undergo total hip arthroplasty for associated hip arthritis. With a matched cohort we investigated the effect of co-existing LSS on aseptic survivorship, functional outcomes, activity levels, overall subjective physical and mental health status, and satisfaction rates in patients undergoing primary THA. The aseptic-implant survivorship was similar in LSS and non-stenosis cohort. Although both cohorts significantly improved, the LSS cohort achieved lower improvements in HHS, UCLA, SF-36 physical, and satisfaction rates than the matched non-stenotic cohort. Surgeons should consider cautioning patients with LSS that although they can expect relief of their arthritic symptoms following THA, they may continue to expect limitations in function, physical-status, activity-levels, and satisfaction rates., (Copyright © 2015 Elsevier Inc. All rights reserved.)

The effect of varying corticosteroid regimens on hip osteonecrosis incidence remains unclear. We performed a meta-analysis and systematic literature review to determine osteonecrosis occurrences in patients taking corticosteroids at varying mean and cumulative doses and treatment durations, and whether medical diagnoses affected osteonecrosis incidence. Fifty-seven studies (23,561 patients) were reviewed. Regression analysis determined significance between corticosteroid usage and osteonecrosis incidence. Osteonecrosis incidence was 6.7% with corticosteroid treatment of >2 g (prednisone-equivalent). Systemic lupus erythematosus patients had positive correlations between dose and osteonecrosis incidence. Each 10 mg/d increase was associated with a 3.6% increase in osteonecrosis rate, and >20 mg/d resulted in a higher osteonecrosis incidence. Clinicians must be wary of osteonecrosis in patients on high corticosteroid regimens, particularly in systematic lupus erythematosus., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Background: Total elbow arthroplasty is an established option for the primary treatment of acute distal humeral fractures, but there are sparse data regarding elbow hemiarthroplasty (EHA) as an alternative. We present the outcome of EHA performed with a modular anatomic prosthesis and a "triceps-on" surgical technique., Methods: Eighteen consecutive patients underwent EHA for an acute fracture. Two patients died, leaving a study group of 16 patients with minimum 2-year follow-up. Clinical evaluation included range of motion; Mayo Elbow Performance Score; Quick Disabilities of the Arm, Shoulder, and Hand score; and Oxford Elbow Score. Radiographic assessment looked at alignment, evidence of loosening, ulnar and radial head wear, heterotopic ossification, and whether healing of the condyles had occurred., Results: Mean follow-up was 35 months (24-79 months). The mean scores were as follows: Mayo Elbow Performance Score, 89.6; shortened Disabilities of the Arm, Shoulder, and Hand score, 11.2; and Oxford Elbow Score, 43.7. The mean flexion and pronation-supination arcs were 116° and 172° respectively. Radial head wear was absent in 13 patients and mild in 3. Ulnar wear was absent in 6 patients, mild in 8, and moderate in 2. Wear was not associated with greater pain or inferior functional scores. There was no sign of aseptic loosening, and complete condylar bone union occurred in 15 elbows. There was 1 complication, a transient ulnar nerve neurapraxia that resolved without intervention., Conclusion: EHA with a modular anatomic implant using a triceps-on approach is a reliable technique for the management of acute unreconstructible distal humeral fractures in older patients., (Crown Copyright © 2015. Published by Elsevier Inc. All rights reserved.)

Background: Aseptic loosening is the most common cause for revisions after lower-extremity total joint arthroplasties, however studies differ regarding the degree to which host factors influence loosening., Questions/purpose: We performed a systematic review to determine which host factors play a role in the development of clinical and/or radiographic failure from aseptic loosening after (1) THA and (2) TKA., Methods: Two searches on THA and TKA, respectively, using four electronic databases (EMBASE, CINAHL Plus, PubMed, and Scopus) were conducted. We identified a total of 209 reports that encompassed nine potential host factors affecting aseptic loosening. Inclusion criteria for consideration of scientific clinical reports were that 20 or more patients were involved, with more than 1-year followup, with at least three studies pertaining to each factor, and at least six of the Methodological Index for Non-randomized Studies criteria met, and with raw data for odds ratio (OR) calculations. Twenty-one studies (16 THA studies with 45,779 hips and five TKA studies with 288 knees, respectively) were used to calculate weighted OR and CIs (using the random effects theory) and study heterogeneity for four different host factors in THAs (male sex, high activity level, obesity defined as BMI≥30 kg/m2, and current or former tobacco use) and one factor in TKA (BMI≥30 kg/m2), which were placed in a forest plot., Results: For THA, male sex (OR, 1.39; 95% CI, 1.22-1.58; p=0.001) and high activity level (University of California Los Angeles [UCLA] activity score≥8 points; OR, 4.24; 95% CI, 2.46-7.31; p=0.001) were associated with aseptic loosening. However, obesity (OR, 1.01; 95% CI, 0.73-1.40; p=0.96), and tobacco use (OR, 1.96; 95% CI, 0.43-8.97; p=0.39) were not associated with an increased risk of aseptic loosening after THA with the numbers available. For TKA, we found no host factors associated with loosening. In particular, obesity (BMI≥30 kg/m2) was not associated with aseptic loosening with the numbers available (OR, 2.28; 95% CI, 0.60-8.62; p=0.22)., Conclusions: Patients undergoing a lower-extremity total joint arthroplasty who engage in impact sports should be counseled regarding their potential increased risk of aseptic loosening; however, given the weak evidence available, we believe that higher-level studies are necessary to clearly define the risk factors, particularly with newer-generation constructs., Level of Evidence: Level IV, therapeutic study.

Titanium-based highly-porous metal cups have been introduced as a relatively new alternative for enhanced acetabular fixation during revision THA; limited number of studies have evaluated its outcomes. We aimed to assess the clinical, functional, and patient-reported outcomes following the use of new generation highly-porous titanium acetabular implants in the revision setting. Seventy-one revisions were (1:1) matched to a conventional porous-coated cohort and were followed-up clinically and radiographically for at least 2-years. Non-significant differences in overall aseptic-survivorship were found across all types of acetabular defects comparing both cohorts (P=0.3). The overall HHS, UCLA, and SF-36 scores were similar between both cohorts. It remains to be seen if the great potential for enhanced osseointegration translates into improved long-term survivorship compared to conventional-porous devices., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Introduction: To assess the success of a total knee arthroplasty (TKA), scoring systems have been developed to provide a straightforward method of evaluating the outcomes of patients following surgery. Fully evaluating these outcomes is a challenging and time consuming task, and these simplistic measures often do not provide a complete picture of a patient's recovery. Therefore, we evaluated different scoring systems to determine the most effective method of assessing the outcomes of patients undergoing total knee arthroplasty., Materials and Methods: We evaluated all knee scoring systems currently available in literature, and a total of 46 questionnaires met our inclusion and exclusion criteria. We then identified all the metrics assessed in the questionnaires (n=48) and subdivided them into objective, subjective, rehabilitative, and quality of life outcome measures. We identified the three most commonly referenced questionnaires (the Knee Society Scores, the Knee Osteoarthritis and Outcomes Scores, and the Western Ontario and McMaster Score-WOMAC) and assessed multiple permutations of these with other scoring systems to identify the combinations that would most comprehensively and efficiently evaluate the outcomes of patients undergoing TKA., Results: Of the 48 metrics, we identified four subjective, eight objective, 20 rehabilitation, and 16 quality of life metrics. On permutation of the three most referenced scoring systems, the KSS and the KOOS together yielded the greatest coverage of the above metrics (79%). When the KSS, KOOS, and WOMAC, respectively, were combined with the Lower Extremity Function Scale (LEFS) and Short Form 36 (SF-36), they yielded 77, 73, and 60% coverage of the metrics and 35, 39, and 37% redundancy, respectively., Conclusion: Surgeons and researchers have attempted to fully evaluate the outcomes of patients undergoing TKA. The proposed combinations may provide a more comprehensive way to cost-effectively evaluate outcomes. Further analysis is required before attempting to create newer knee scoring systems.

Multiple scoring systems have been developed for the assessment of outcomes following total knee arthroplasty. However, few studies have comprehensively evaluated each scoring system to analyze the various outcome variables and their individual weightings toward generations of the final score. A systematic search of four electronic databases were performed from January 1960 to August, 2013 to identify studies that reported on knee scores and to sub-categorize the outcomes measured based on subjective, objective, rehabilitative, and quality of life outcomes. We also evaluated the outcome metrics that each of these systems measured to identify the relative impact of these variables toward the final score. We identified 45 different outcome metrics in 46 rating scales. Pain (80%), stiffness (13%), and swelling (13%) were the three most common subjective outcomes measured in the scoring systems, while measurements of range-of-motion (57%), flexion contracture (39%), and coronal plane deformity (35%) were the most often reported objective outcome variables. Of all the variables measured, we found that pain (mean weighted score, 26 points; range, 0 to 50 points), range-of-motion (mean weighted score, 11 points; range, 0 to 50 points), distance walked (mean weighted score, 7 points; range, 0 to 30 points), ability to climb stairs (mean weighted score, 6 points; range, 0 to 20 points), ability to rise from sitting position (mean weighted score, 4 points; range, 0 to 20 points), and presence of a flexion contracture (mean weighted score, 4 points, range, 0 to 20 points) had the greatest impact on the final score standardized to 100 points. Currently, few rating scales exist that assess all aspects of functional, rehabilitative, and quality of life outcomes including patient satisfaction within the realms of a single scoring system. Further research is needed to determine the optimal combination and weightings of the individual outcomes metrics to better evaluate overall outcomes following total knee arthroplasty and to develop a more comprehensive scoring system.

Post-traumatic arthritis of the hip can develop in 12-57% of patients after an acetabular fracture. Once it develops, salvage treatment options include arthroplasty or arthrodesis. Delayed total hip arthroplasty (THA) has been shown to be a viable treatment option to decrease pain, improve stability and increase functional outcomes. Using cemented designs, earlier long-term studies reported satisfactory functional outcomes of delayed THA used to treat previously failed acetabular fractures. However, high aseptic loosening rates were also observed. Recent advances in cementless acetabular designs have shown comparable functional outcomes and loosening rates compared to those undergoing THA for non-traumatic arthritis. However, even with improvements in functional and radiographic outcomes, unique complications are commonly encountered in patients with previous acetabular fractures, including heterotopic bone around the hip, increased operative times and blood loss, aseptic loosening, sciatic nerve injury and dislocation. The outcomes and complications of delayed THA in patients with previous acetabular fracture will be reviewed.

Unfavorable outcomes from trunnion fretting and corrosion damage have been reported in the literature, gross failures of tapers in primary total hip arthroplasties have been less frequently reported. We report on 5 patients, who presented with gross trunnion failures of modular metal-on-polyethylene or ceramic-on-polyethylene bearings from 5 implant manufacturers, all necessitating revision surgery. None of these patients had an antecedent history of trauma, and the majority presented with pain or instability. No common factor was identified that may be predictive of these type of failures. Since there were 5 different stem designs, this suggests that it may be a rare generic phenomenon occurring with multiple designs. Currently, further investigations are necessary, including retrieval analysis, to identify risk factors that may predispose to such failures., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Steep cup abduction angles with adverse joint loading may increase traditional polyethylene bearing wear in total hip arthroplasties. However, there have been few reports evaluating the effect of cup inclination on the wear of dual-mobility devices. In a hip joint simulation, we compared the short-term wear of two-sizes of modular highly cross-linked dual-mobility bearings (28 mm femoral head diameter/42 mm polyethylene insert outer diameter/54 mm acetabular shell diameter; 22.2 mm femoral head diameter/36 mm polyethylene insert outer diameter/48 mm acetabular shell diameter) at 50 and 65° of cup inclination with modular 28 mm femoral head on 54 mm cup diameter metal-on-highly cross-linked polyethylene bearings. Increasing inclination from 50-65° had no changes in volumetric wear of 28/42/54 mm (mean, 1.7 vs. 1.2 mm3 /million cycles, respectively; p = 0.50) and 22.2/36/48 mm (mean, 1.7 vs. 1.2 mm3/million cycles, respectively; p = 0.48) dual mobility bearings. At 65°, 22.2/36/48 mm dual-mobility bearings had lower volumetric loss (mean, 2.2 vs. 6.3 mm(3) ; p = 0.03) and wear rates (mean, 1.2 vs. 2.7 mm3/million cycles; p = 0.02) compared to metal-on-highly cross-linked polyethylene bearings. Modern-generation dual-mobility designs with highly cross-linked polyethylenes may potentially withstand edge-loading from steeper cup-inclinations without substantial decreases in wear., (© 2014 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.)

Osteonecrosis of the hip can lead to advanced arthritis in typically young patients. Hematologic disorders comprise one group of potential causes. These include sickle cell anemia, hemophilia, aplastic anemia, thalassemia, and acute lymphoblastic leukemia. Depending on the stage of disease, treatment options include non-operative management, joint-preserving procedures (percutaneous drilling, core decompression, and vascularized or non-vascularized bone grafting), and joint arthroplasty (resurfacing arthroplasty and THA). Numerous small studies have investigated the efficacy of these options in patients who have specific hematologic disorders. Therefore, this report provides a comprehensive review of the osteonecrosis treatment options and results across the spectrum of patients who have various hematologic disorders.

As the number of primary total hip arthroplasties increase over the next several decades so will the incidence of periprosthetic fractures around the femoral stem. Treatment can reliably be predicted using the Vancouver classification with internal fixation being indicated in fractures involving a stable implant and revision arthroplasty indicated in those with unstable prostheses. Non-displaced fractures involving the greater and lesser trochanter can generally be treated non-operatively. Extensively porous-coated stems and the use of modular uncemented revision stems to treat Vancouver B fractures have shown encouraging results. The treatment of Vancouver C periprosthetic fractures continues to follow basic AO fixation principles with an emphasis on eliminating stress risers with adequate implant overlap and length. This review will focus on the risk factors and classification of these fractures, as well as highlight the treatment options for post-operative periprosthetic femoral fractures around a total hip arthroplasty.

Robotics in total knee arthroplasty (TKA) has undergone vast improvements. Although some of the systems have fallen out of favor due to safety concerns, there has been recent increased interest for semi-active haptic robotic systems that provide intraoperative tactile feedback to the surgeon. The potential advantages include improvements in radiographic outcomes, reducing the incidence of mechanical axis malalignment of the lower extremity and better tissue balance. Proponents of robotic technology believe that these improvements may lead to superior functional outcomes and implant survivorship. We aim to discuss robotic technology development, outcomes of unicompartmental and total knee arthroplasty and the future outlook. Short-term follow-up studies on robotic-assisted knee arthroplasty suggest that, although some alignment objectives may have been achieved, more studies regarding functional outcomes are needed. Furthermore, studies evaluating the projected cost-benefit analyses of this new technology are needed before widespread adoption. Nevertheless, the short-term results warrant further evaluation.

Variations in the origin of the long head of biceps tendon (LHBT) have been described in literature; however, its clinical significance remains uncertain. We describe in this report, the history, physical examination and the arthroscopic findings in a patient who had an anomalous origin of the LHBT from the rotator cuff, resulting in restriction of range of motion. This anomalous origin of the long head of biceps tendon causing capsular contracture and restriction of movements leading to secondary internal impingement, has not been extensively reported in the literature. Shoulder arthroscopists should be aware that, although, an uncommon clinical condition, the aberrant congenital origin of the LHBT from the rotator cuff can rarely become pathologic in middle age and lead to shoulder dysfunction. In such cases, release of the anomalous band may be required, along with the treatment of other concomitant intraarticular pathologies in the glenohumeral joint.

Recent advances in the wear characteristics and material properties of highly cross-linked polyethyl-ene and fourth-generation ceramic bearings have led to increasing use of large-diameter (≥ 36 mm) femoral heads in total hip arthroplasty (THA). In this article, we review the current concepts and principles behind use of large-diameter ceramic or cobalt-chromium femoral heads on polyethylene bearings in THA. We specifically review the biomechanics, some of the early concerns about polyethylene wear and rim fractures, recent improvements in material properties of polyethylene and ceramic bearings, dislocation rates, and clinical and functional outcomes of large-diameter heads in THA. Recent literature suggests that the incidence of dislocation has been substantially reduced because of improvements in jump distance and impingement-free range of motion with use of large-diameter heads. Limited evidence suggests excellent short-term and midterm clinical and functional outcomes with these heads.

➤ Short bone-conserving femoral stems in total hip arthroplasty were designed to preserve proximal bone stock.➤ Given the distinct fixation principles and location of loading among these bone-conserving stems, a classification system is essential to compare clinical outcomes.➤ Due to the low quality of currently available evidence, only a weak recommendation can be provided for clinical usage of certain stem designs, while some other designs cannot be recommended at this time.➤ A high prevalence of stem malalignment, incorrect sizing, subsidence, and intraoperative fractures has been reported in a subset of these short stem designs.➤ Stronger evidence, including prospective multicenter randomized trials comparing standard stems with these newer designs, is necessary before widespread use can be recommended., (Copyright © 2014 by The Journal of Bone and Joint Surgery, Incorporated.)

Patients referred to orthopedists for hip pain due to arthritis may already have MRI studies ordered by their referring physicians despite plain radiographs being sufficient in most cases. Hence, we prospectively evaluated every patient referred to our institution during a 36-month period to identify the number of new patients with hip osteoarthritis who had an unnecessary MRI, the additional costs of these MRIs, and the extrapolated cost to the United States healthcare system during the next 10years. Overall, 15.4% of the patients presented with unnecessary MRIs, approximately, 330 to 440.5 million dollars may be spent on unnecessary hip MRIs in this patient population in America. We believe that referring physicians should not simultaneously order a radiograph and an MRI to evaluate hip pain., (Copyright © 2014 Elsevier Inc. All rights reserved.)

Background: Manipulation under anesthesia has been reported to improve range of motion when other rehabilitative efforts fail to obtain adequate motion after total knee arthroplasty. The purpose of this study was to evaluate the effects of the timing of the manipulation on knee range of motion and clinical outcomes., Methods: All 2128 total knee arthroplasties performed at our institution from 2005 to 2011 were reviewed to determine the number of patients who had undergone manipulation under anesthesia. A total of 144 manipulations in eighty-eight women and forty-five men were reviewed. Manipulations under anesthesia that were performed within the first twelve weeks after total knee arthroplasty were considered early and those after that period were considered late. Patients were further substratified according to the timing of the manipulation: Group I included those who had the manipulation within six weeks; Group II, at seven to twelve weeks; Group III, at thirteen to twenty-six weeks; and Group IV, after twenty-six weeks. Outcomes evaluated included gains in flexion and final range of motion, and Knee Society objective and function scores between early and late manipulation, using various adjusted multivariable regression models and at a mean follow-up of fifty-one months (range, twelve to eighty-one months). Mediation analysis was used to investigate whether gains in range of motion from the manipulations under anesthesia alone had mediated the effect between the timing of the manipulation and the clinical outcomes., Results: Patients who underwent early manipulation had a significantly higher mean gain in flexion (36.5° versus 17°), higher final range of motion (119° versus 95°), and higher Knee Society objective (89 versus 84 points) and function scores (88 versus 83 points) than those who had late manipulation under anesthesia. There were no significant differences in the outcomes of Groups I and II. Manipulations after twenty-six weeks resulted in unsatisfactory clinical outcomes. Multivariable regression analyses confirmed significantly better clinical outcomes with early manipulation. Mediation analysis showed that the timing of manipulation independently had significantly contributed to the outcomes., Conclusions: Orthopaedic surgeons should have a low threshold for performing early manipulations with the patient under anesthesia within twelve weeks after an arthroplasty, to achieve higher knee range of motion and improved clinical outcomes., Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence., (Copyright © 2014 by The Journal of Bone and Joint Surgery, Incorporated.)

Surgical site infections following lower extremity total joint arthroplasty procedures remain a substantial economic burden to the patient, the treating institution, and the health care system. The complexity of these surgical procedures creates the potential for various patient- or surgery-related risk factors for infection. Although there is much literature regarding the use of many preventative methods, a consensus regarding the true efficacy and application of such practices is generally not available. In this review, we reviewed the preoperative skin disinfection methodologies that have been used for reducing periprosthetic infections following lower extremity total joint arthroplasty. Currently, cumulative evidence suggests that preoperative chlorhexidine baths or chlorhexidine-impregnated wipes may reduce the colonization of pathogenic organisms on the skin. In addition, multiple showers or topical applications of chlorhexidine may lead to more substantial reduction in colony counts. Advanced preoperative whole-body cleaning with chlorhexidine-containing cloths rather than site-specific application may confer additional advantages. Further randomized controlled trials with carefully planned protocols and endpoints are needed to determine if this conclusively leads to reduction in the rate of surgical site infections., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Total knee arthroplasty (TKA) has been shown to have excellent long-term outcomes and survivorship in numerous studies, however, with changes in patient demographics, questions have arisen about the use of conventional arthroplasties and their functionality in highly active, young patients. The recent interest in bicruciate-retaining prostheses is aimed to address the need for an implant that can mimic a natural knee during high activity levels. Although there are currently few of these prostheses which are being utilized, results from prior studies have demonstrated similar results to that of anterior cruciate ligament-sacrificing TKA in terms of function and survivorship. In this review, we will describe the history, kinematics, clinical outcomes, concerns, and future outlook of bicruciate-retaining arthroplasty., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Additive manufacturing is an industrial technology whereby three-dimensional visual computer models are fabricated into physical components by selectively curing, depositing, or consolidating various materials in consecutive layers. Although initially developed for production of simulated models, the technology has undergone vast improvements and is currently increasingly being used for the production of end-use components in various aerospace, automotive, and biomedical specialties. The ability of this technology to be used for the manufacture of solid-mesh-foam monolithic and coated components of complex geometries previously considered unmanufacturable has attracted the attention of implant manufacturers, bioengineers, and orthopedic surgeons. Currently, there is a paucity of reports describing this fabrication method in the orthopedic literature. Therefore, we aimed to briefly describe this technology, some of the applications in other orthopedic subspecialties, its present use in hip and knee arthroplasty, and concerns with the present form of the technology. As there are few reports of clinical trials presently available, the true benefits of this technology can only be realized when studies evaluating the clinical and radiographic outcomes of cementless implants manufactured with additive manufacturing report durable fixation, less stress shielding, and better implant survivorship. Nevertheless, the authors believe that this technology holds great promise and may potentially change the conventional methods of casting, machining, and tooling for implant manufacturing in the future., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)