JAAOS Global Research & Reviews最新文献

{"title":"Leadership Trends in Shoulder and Elbow Surgery Fellowship Directors: A Cross-sectional Study","authors":"Amandeep Chopra, Melissa A. Wright, Christopher S. Klifto, O. Anakwenze, A. Murthi","doi":"10.5435/JAAOSGlobal-D-21-00266","DOIUrl":"https://doi.org/10.5435/JAAOSGlobal-D-21-00266","url":null,"abstract":"Introduction: We aimed to describe the demographic and professional backgrounds of current shoulder and elbow fellowship directors. Methods: The American Shoulder and Elbow Surgeons (ASES) 2021 to 2022 Fellowship Directory was reviewed to identify the 31 ASES-recognized US fellowship programs. Demographic and other data were obtained through an electronic survey and publicly available online resources from February 28, 2021, to March 5, 2021. Results: Of the 31 fellowship directors, 97% (30) identified as male and 74% (23) as White, the mean age was 53 ± 7 years, and the mean Scopus h-index was 24.2 ± 13. Almost all (95%) held ASES committee leadership appointments in at least one committee. The mean time from completion of most recent fellowship to fellowship director appointment was 7.3 ± 6 years. About two-thirds of fellowship directors trained at one of five fellowship programs: Columbia University (n = 7), California Pacific Orthopaedics (n = 4), Washington University in St. Louis (n = 3), Mayo Clinic (n = 3), and Hospital for Special Surgery (n = 2). Discussion: ASES fellowship directors share similar demographic and professional characteristics with high levels of research productivity and involvement in orthopaedic societies. There is a lack of diversity in shoulder and elbow fellowship directors, highlighting a need for priority consideration of this disparity by leaders in the field.","PeriodicalId":145112,"journal":{"name":"JAAOS Global Research & Reviews","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114513105","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Prosthetic Knee Joint Infection Caused by Mycobacterium kansasii","authors":"Suhas P. Dasari, Adam Hadro, Reena Singh, J. Neilson","doi":"10.5435/JAAOSGlobal-D-21-00183","DOIUrl":"https://doi.org/10.5435/JAAOSGlobal-D-21-00183","url":null,"abstract":"Mycobacterium kansasii is a nontuberculous mycobacterium that is a rare cause of prosthetic joint infections (PJIs). This case report presents a 58-year-old man who developed rapidly progressive arthritis after exposing his right knee to an unknown fluid at a microbial pharmaceutical company. Within a year, he underwent a right total knee arthroplasty (TKA). At 5 months postoperatively, he presented with pain and swelling of that knee. Imaging revealed extensive periprosthetic osteolysis with diffuse intracapsular and posterior extracapsular fluid collections. Multiple knee aspirates had negative cultures, and infectious laboratory test results were equivocal. Two years after his primary arthroplasty, the patient underwent posterior débridement and one-stage revision TKA with antibiotic cement. Synovial fluid mycobacterial cultures aspirated 2 weeks before the revision surgery became positive on postoperative day 1. PCR identified M kansasii. At 3 weeks postoperatively, intraoperative periprosthetic cultures grew mycobacterium. M kansasii was confirmed using mass spectrometry. Once susceptibilities returned, the patient was treated with targeted antimycobacterial therapy. This case report demonstrates the importance of considering atypical PJI in painful TKA with negative cultures and equivocal laboratory results. In the future, when there is concern for an atypical PJI, molecular diagnostic tools and mycobacterial cultures should be used before surgical intervention.","PeriodicalId":145112,"journal":{"name":"JAAOS Global Research & Reviews","volume":"82 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116310855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Staged Correction of Severe Recurrent Clubfoot Deformity With Dislocation of the Chopart Joint Using a Hexapod External Fixator and Unconventional Arthrodesis","authors":"Allen Kadado, N. Akioyamen, Rachel Garfinkel, Nickolas J. Nahm, Ferras Zeni","doi":"10.5435/JAAOSGlobal-D-21-00116","DOIUrl":"https://doi.org/10.5435/JAAOSGlobal-D-21-00116","url":null,"abstract":"Despite success of the Ponseti method, a subset of patients with clubfeet experience residual deformity. Surgical release after unsuccessful serial casting can lead to residual clubfoot deformities, including a flat-top talus. We present a case of a 17-year-old boy with a dysmorphic ankle and a complete dorsal dislocation of the Chopart joint. Because of pain with activities and functional limitations, the patient underwent a staged correction of the dislocation. The deformity was corrected through a staged approach using a Taylor Spatial Frame, navicular excision, talocuneiform arthrodesis, and calcaneocuboid arthrodesis. One year postoperatively, the patient is pain free with notable functional gains.","PeriodicalId":145112,"journal":{"name":"JAAOS Global Research & Reviews","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128975840","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Indolent Infection After Lumbar Interbody Fusion: An Under-recognized Cause of Pseudarthrosis, Which Can Be Successfully Treated With Anterior Revision Fusion","authors":"Andrew S. Zhang, Ellis M. Berns, D. Hartnett, Eren O. Kuris, Alan H. Daniels","doi":"10.5435/JAAOSGlobal-D-21-00259","DOIUrl":"https://doi.org/10.5435/JAAOSGlobal-D-21-00259","url":null,"abstract":"Introduction: Bacterial infection is a common etiology for pseudarthrosis after transforaminal lumbar interbody fusion, although it is often difficult to identify because of a delayed presentation and normal laboratory values. The primary goal of this study was to present a series of cases demonstrating patients with infection-related pseudarthrosis successfully managed with anterior revision. Methods: We retrospectively reviewed patients presenting to a single academic spine center who were found to have evidence of Cutibacterium acnes or coagulase-negative Staphylococcus infection on routine culturing of lumbar interbody fusion revisions from July 2019 to January 2021. All patients underwent salvage of a transforaminal lumbar interbody fusion pseudarthrosis through an anterior lumbar approach. Results: A total of six patients managed for pseudarthrosis secondary to suspected infection were eligible for this study (mean age 64.8 years, range 54-70 years; mean body mass index, range 24.5-39.1). Persistent radiculopathy was the primary presenting symptom in all patients with a mean time to revision of 17 months. Coagulase-negative Staphylococcus was the primary pathogen, identified from intraoperative samples in 50% of the cases. All patients demonstrated a resolution of symptoms after placement of an anterior lumbar interbody cage, without intraoperative complications, and a subsequent antibiotic regimen. Discussion: Indolent infection is an under-recognized cause of pseudarthrosis of the lumbar spine. Revision surgery through an anterior lumbar approach, which promotes ease of cage removal and optimized alignment and surface area available for revision fusion, is sufficient to manage pseudarthrosis due to infection.","PeriodicalId":145112,"journal":{"name":"JAAOS Global Research & Reviews","volume":"27 10 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123697053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surgical Versus Nonsurgical Management of Acetabular Fractures With Associated Patterns in Elderly Patients: Factors Affecting Outcomes","authors":"Isabella M. Heimke, Nicholas R. Scarcella, Natasha M. Simske, R. Furdock, H. Vallier","doi":"10.5435/JAAOSGlobal-D-22-00014","DOIUrl":"https://doi.org/10.5435/JAAOSGlobal-D-22-00014","url":null,"abstract":"Introduction: Among elderly patients, anterior column posterior hemitransverse (ACPHT) and associated both column (ABC) are common acetabular fracture patterns after low-energy mechanisms. Given the paucity of outcomes data in this cohort, the goal of this study was to determine the favorability of results with surgical versus nonsurgical management. Secondarily, factors linked with poor functional outcomes were assessed. Methods: Over a 16-year period, 81 patients aged ≥60 years with 82 ACPHT and ABC acetabular fractures were evaluated. Retrospectively, patient demographics, injury details, and early and late complications were collected. Functional outcomes were assessed with the Musculoskeletal Function Assessment (MFA) after a minimum of 12 months of follow-up. Results: During the study period, 81 patients sustained 82 ACPHT (n = 35, 43%) or ABC (n = 47) fractures, most secondary to low-energy falls (71%). Patients managed surgically were younger, had higher-energy mechanisms, and more often had an associated hip dislocation or marginal impaction (all P < 0.05). Of note, 42.3% and 18.5% of patients had early and late complications, respectively, with no differences between surgical and nonsurgical groups. Posttraumatic arthrosis (PTA) was noted in 27% overall (36% surgical versus 16% nonsurgical, P = 0.10). The mean MFA score was 25.2 after 59 months. Better outcomes were associated with high-energy mechanisms, multiple injuries, and surgical management (all P < 0.05). The worst MFA outcomes were among patients with PTA (40.2) and those requiring a secondary procedure (45.7), both P < 0.05. Discussion: Nonsurgical management had a low rate of PTA. Mitigating PTA and decreasing the rate of secondary surgeries seem crucial achieving satisfactory outcomes. Higher-energy injuries benefit from open reduction and internal fixation, as indicated by better MFA scores.","PeriodicalId":145112,"journal":{"name":"JAAOS Global Research & Reviews","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"129570575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Body Composition Predictors of Adverse Postoperative Events in Patients Undergoing Surgery for Long Bone Metastases","authors":"P. Twining, O. Groot, Colleen G. Buckless, N. D. Kapoor, M. Bongers, S. Janssen, J. Schwab, M. Torriani, M. Bredella","doi":"10.5435/JAAOSGlobal-D-22-00001","DOIUrl":"https://doi.org/10.5435/JAAOSGlobal-D-22-00001","url":null,"abstract":"Introduction: Body composition assessed using opportunistic CT has been recently identified as a predictor of outcome in patients with cancer. The purpose of this study was to determine whether the cross-sectional area (CSA) and the attenuation of abdominal subcutaneous adipose tissue, visceral adipose tissue (VAT), and paraspinous and abdominal muscles are the predictors of length of hospital stay, 30-day postoperative complications, and revision surgery in patients treated for long bone metastases. Methods: A retrospective database of patients who underwent surgery for long bone metastases from 1999 to 2017 was used to identify 212 patients who underwent preoperative abdominal CT. CSA and attenuation measurements for subcutaneous adipose tissue, VAT, and muscles were taken at the level of L4 with the aid of an in-house segmentation algorithm. Bivariate and multivariate linear and logistic regression models were created to determine associations between body composition measurements and outcomes while controlling for confounders, including primary tumor, metastasis location, and preoperative albumin. Results: On multivariate analysis, increased VAT CSA {regression coefficient (r) (95% confidence interval [CI]); 0.01 (0.01 to 0.02); P < 0.01} and decreased muscle attenuation (r [95% CI] −0.07 [−0.14 to −0.01]; P = 0.04) were associated with an increased length of hospital stay. In bivariate analysis, increased muscle CSA was associated with increased chance of revision surgery (odds ratio [95% CI]; 1.02 [1.01 to 1.03]; P = 0.04). No body composition measurements were associated with postoperative complications within 30 days. Discussion: Body composition measurements assessed using opportunistic CT predict adverse postoperative outcomes in patients operated for long bone metastases.","PeriodicalId":145112,"journal":{"name":"JAAOS Global Research & Reviews","volume":"64 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128874634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lower Extremity Osteoarthritis: A Risk Factor for Mental Health Disorders, Prolonged Opioid Use, and Increased Resource Utilization After Single-Level Lumbar Spinal Fusion","authors":"Justin J. Turcotte, P. King, C. Patton","doi":"10.5435/JAAOSGlobal-D-21-00280","DOIUrl":"https://doi.org/10.5435/JAAOSGlobal-D-21-00280","url":null,"abstract":"Introduction: Few studies have examined the effect of hip or knee osteoarthritis, together described as lower extremity osteoarthritis (LEOA) on patient outcomes after lumbar fusion. The purpose of this study was to evaluate the effect of LEOA on postoperative outcomes and resource utilization in patients undergoing single-level lumbar fusion. Methods: Using a national deidentified database, TriNetX, a retrospective observational study of 17,289 patients undergoing single-level lumbar fusion with or without a history of LEOA before September 1, 2019, was conducted. The no-LEOA and LEOA groups were propensity score matched, and 2-year outcomes were compared using univariate statistical analysis. Results: After propensity score matching, 2289 patients with no differences in demographics or comorbidities remained in each group. No differences in the rate of repeat lumbar surgery were observed between groups (all P > 0.30). In comparison with patients with no LEOA, patients with LEOA experienced higher rates of overall and new onset depression or anxiety, prolonged opioid use, hospitalizations, emergency department visits, and ambulatory visits over the 2-year postoperative period (all P < 0.02). Conclusion: Patients with LEOA undergoing single-level lumbar fusion surgery are at higher risk for suboptimal outcomes and increased resource utilization postoperatively. This complex population may benefit from additional individualized education and multidisciplinary management.","PeriodicalId":145112,"journal":{"name":"JAAOS Global Research & Reviews","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114065354","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Bone Health Optimization on Osteoporosis Screening and Treatment Before Thoracolumbar Fusion","authors":"J. Bernatz, Alec E. Winzenried, Kristyn J. Hare, A. Mikula, Seth K. Williams, N. Binkley, P. Anderson","doi":"10.5435/JAAOSGlobal-D-21-00253","DOIUrl":"https://doi.org/10.5435/JAAOSGlobal-D-21-00253","url":null,"abstract":"Objective: Osteoporosis is not rare in thoracolumbar spine fusion patients and may portend poorer surgical outcomes. Implementation of a bone health optimization (BHO) clinic improves osteoporosis screening and treatment in the total joint arthroplasty population. We hypothesize that preoperative osteoporosis is common, under-recognized, and undertreated in thoracolumbar fusion patients and that a BHO clinic will increase preoperative osteoporosis screening rates and pharmacologic osteoporosis treatment in this population. Methods: This retrospective case series includes adults older than 30 years who underwent elective thoracolumbar spine fusion at a single tertiary care center before and after creation of a BHO referral clinic. Data collected included preoperative osteoporosis risk factors, prior dual-energy radiograph absorptiometry testing, and prior osteoporosis pharmacotherapy. Fracture risk was estimated using the fracture risk assessment tool with and without bone mineral density (BMD), and the US National Osteoporosis Foundation criteria for screening and treatment were applied. Results: Ninety patients were included in the pre-BHO group; 53 patients met criteria for BMD measurement, but only 10 were tested within 2 years preoperatively. Sixteen patients (18%) met criteria for osteoporosis pharmacotherapy, but only 5 of the 16 (31%) received osteoporosis medication within 6 months of surgery. There were 87 patients in the post-BHO group, and 19 were referred to the BHO clinic. BMD measurement was done in 17 of the patients (89%) referred to the BHO clinic compared with 10% for those not referred. All patients (n = 7) referred to the BHO clinic meeting treatment criteria received treatment within 6 months before surgery, whereas only 25% of the patients not referred received treatment. Discussion: Osteoporosis is not rare in adults undergoing thoracolumbar spine fusion with ∼13% to 18% meeting criteria for pharmacotherapy. Preoperative BHO referral increases screening and treatment.","PeriodicalId":145112,"journal":{"name":"JAAOS Global Research & Reviews","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121177473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison of Short, Intermediate, and Long Cephalomedullary Nail Length Outcomes in Elderly Intertrochanteric Femur Fractures","authors":"Tanner Womble, Andrew Kirk, Maxwell Boyle, Shea M. Comadoll, L. Su, Arjun Srinath, Paul E. Matuszewski, Arun Aneja","doi":"10.5435/JAAOSGlobal-D-21-00322","DOIUrl":"https://doi.org/10.5435/JAAOSGlobal-D-21-00322","url":null,"abstract":"Introduction: Cephalomedullary nail (CMN) length for intertrochanteric femur fractures without subtrochanteric extension has been an ongoing debate. The authors hypothesize that increasing nail length would result in increasing surgical time, greater incidence of acute kidney injury (AKI), postoperative anemia, and blood loss requiring transfusion due to increased intramedullary reaming and pressurization of the canal with nail insertion. Methods: A retrospective chart review of patients aged 65 years or older who underwent CMN for low-energy intertrochanteric femur fractures from 2010 to 2018 was undertaken. Patient demographic data, comorbidities, case duration, postoperative hospital length of stay (LOS), and laboratory data, including serum creatinine, hemoglobin, and hematocrit, were collected for analysis. The following outcome measures were compared: postoperative pneumonia, cardiac complications, sepsis, reintubation/intensive care unit stay, pulmonary embolism, stroke, postoperative AKI, 30-day hospital readmission, 30-day return to operating room, 30-day mortality, 1-year mortality, postoperative anemia (hemoglobin <7 g/dL), and blood transfusion. Results: A total of 247 patients were analyzed (short = 48, intermediate = 39, and long = 160). No notable difference was observed in postoperative pneumonia, cardiac complications, sepsis, reintubation/intensive care unit stay, pulmonary embolism, stroke, mean total hospital LOS, mean postoperative hospital LOS, rate of postoperative AKI, 30-day readmission, 30-day return to operating room, 30-day mortality, or 1-year mortality. Patients receiving long nails had significantly higher rates of postoperative anemia (P = 0.0491), blood transfusion (P = 0.0126), and mean procedure length (P = 0.0044) compared with the two other groups. Discussion: Patients receiving long nails had markedly higher rates of postoperative anemia and blood loss requiring blood transfusion with markedly longer mean procedure length than patients receiving short and intermediate CMNs. Long nails did not result in an increase in other complications evaluated.","PeriodicalId":145112,"journal":{"name":"JAAOS Global Research & Reviews","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130132639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Letter to the Editor: Type IV Is Not Type IV","authors":"T. W. Bauer","doi":"10.5435/jaaosglobal-d-21-00313","DOIUrl":"https://doi.org/10.5435/jaaosglobal-d-21-00313","url":null,"abstract":"To the Editor: This concerns important misconceptions inherent in a review article entitled: “Metal hypersensitivity in joint arthroplasty” by Johannes Michiel van der Merwe (JAAOS Glob Res Rev 2021;5:1-8).1 Different types of hypersensitivity reactions are often classified according to the Gell-Coombs Classification2 published in 1963. Although far from perfect, this commonly used classification is a good starting point for discussing the pathogenesis, symptoms, pathology, and treatment of various types of hypersensitivity reactions (Table 1). Histologic findings in tissue associated with a hypersensitivity reaction often reflect the underlying pathophysiology. For example, a mucosal biopsy associated with a type I reaction is likely to show edema, mast cells, and eosinophils. In type II hypersensitivity, IgG and IgM may cause cell lysis or induce subsequent phagocytosis of affected cells by macrophages without inflammation. Type IV hypersensitivity involves lymphocytes and macrophages and may demonstrate granulomas. The adaptive immune reaction that some patients develop in response to metal ions or particles from articular surfaces or modular connections is thought to represent a type IV hypersensitivity reaction. Van der Merwe notes, “MH [metal hypersensitivity] is a type IV HS [hypersensitivity] reaction.”He further notes, “the difference between a type IV HS reaction and a type I or II HS reaction is that no or very small amounts of wear particles or inflammatory infiltrates are seen histologically in type IV reactions.” That statement makes no sense in the context of the Gell-Coombs Classification that we all use in the context of hypersensitivity reactions, but a review of citation 15 reveals the problem: Van der Merwe is not referring to the Gell-Coombs Classification of hypersensitivity reactions but, instead, is referring to the Krenn3 modification of the Morawietz4 classification of periprosthetic histology, which is only indirectly related to hypersensitivity (Table 2). Van der Merwe has modified the Krenn classification without adequate citations in his Figure 2, incorrectly suggesting that the Krenn classification refers to four different types of hypersensitivity reactions. In fact, Krenn type I represents an innate, macrophage reaction to particles (not a hypersensitivity reaction at all), and type II reflects periprosthetic infection. The histology of Krenn type I contains macrophages, giant cells, and debris, while Krenn type II contains neutrophils, but this is not true of Gell-Coombs Types I and II. Van der Merwe further confuses readers by attempting to merge the two classifications, for example, suggesting that type 2 with neutrophils represents hypersensitivity. It does not; it represents periprosthetic infection. Readers of JAAOS Global Research & Reviews should interpret the contents of the van der Merwe review with caution.","PeriodicalId":145112,"journal":{"name":"JAAOS Global Research & Reviews","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2022-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124158108","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}