HSS Journal®: The Musculoskeletal Journal of Hospital for Special Surgery

Background: Patients with inflammatory arthritis are at increased risk of prosthetic joint infections (PJIs), but diagnosis in these patients can be challenging because active inflammatory arthritis produces elevated inflammatory markers that may mimic those seen in PJI. Purpose: In this pilot study, we sought to identify the clinical, microbiologic, and histopathologic features of culture-positive and culture-negative PJI in patients with inflammatory arthritis who underwent total hip arthroplasty (THA) or total knee arthroplasty (TKA). We also sought to obtain preliminary data to support a definitive study of optimal methods for PJI diagnosis in patients with inflammatory arthritis. Methods: We performed a retrospective analysis of TKA and THA patients treated for PJI from 2009 to 2018 at a single tertiary care orthopedic institution. Data were extracted from a longitudinally maintained hospital infection database. We reviewed hematoxylin and eosin slides of osteoarthritis and inflammatory arthritis PJI cases matched 3:1, respectively, by age, sex, and culture status. Clinical characteristics were evaluated using the Fisher exact test, χ² test, Student t test, and Mann-Whitney U test where appropriate. Results: A total of 807 PJI cases were identified (36 inflammatory arthritis and 771 osteoarthritis cases). Patients with inflammatory arthritis presented younger, had a higher Charlson Comorbidity Index, more frequently used glucocorticoids, were more likely women, and had a higher proportion of culture-negative PJI compared with osteoarthritis patients. Of the 88 inflammatory arthritis cases reviewed for histopathology, a higher proportion of culture-positive than culture-negative PJI cases had >10 polymorphonuclear leucocytes per high-power field and met Musculoskeletal Infection Society criteria but presented with less chronic inflammation. Conclusions: This retrospective prognostic study suggests that culture-negative PJI may be more frequent in patients with inflammatory arthritis than in those with osteoarthritis. Chronic infections, antibiotic use, or misdiagnosis may be contributing factors to unclear PJI diagnoses among culture-negative cases. This preliminary work supports the need for further studies to assess the differences in clinical features between culture-negative and culture-positive PJI in patients with inflammatory arthritis and the ability of biological diagnostic markers to discriminate between them in this population.

Background: Athletes who participate in sports that involve cutting and pivoting movements are particularly susceptible to anterior cruciate ligament (ACL) injury. Preventing this injury is the best way to combat its health consequences and costs. There may be a dose-response relationship between adherence and injury reduction. Purpose: We sought to examine whether athletes’ adherence to injury prevention programs (IPPs) is associated with reductions in ACL and lower extremity (LE) injuries. Methods: We conducted a systematic review of the PubMed, EMBASE, and Cochrane Library databases, searching for studies published between 2011 and 2021. Studies were included if they reported on the use of an ACL IPP compared with a control group and recorded the rate of injuries to calculate a rate ratio, as well as adherence to the program as a percentage of sessions performed. For the meta-analysis, the rate ratios were pooled using the DerSimonian-Laird random-effects model. Results: For the 15 studies included (11 randomized controlled trials and 4 cohort studies), the random-effects model grouped athletes’ adherence to an IPP as high (76% or more of the sessions), moderate (51%–75% of the sessions), and low (50% or fewer of the sessions). We found that athletes with the highest level of IPP adherence had a significantly lower incidence of ACL injury. The rate ratios for moderate and low adherence did not demonstrate a reduced incidence of ACL injury. Injury prevention program participation was also associated with a decrease in LE injury rates. Conclusion: This systematic review and meta-analysis found that athletes with high adherence to IPPs had reduced rates of ACL and LE injuries. Our findings suggest that educating coaches and athletes on the dose-dependent benefits of IPPs may promote the routine incorporation of these programs into warm-up sessions to decrease the risk of ACL and LE injuries.

Background: Assessing the impact of spine disorders such as lumbar degenerative spondylolisthesis (LDS) on overall health is a component of quality of care that may not be comprehensively captured by spine-specific and single-attribute patient-reported outcome measures (PROMs). Purpose: We sought to compare PROMs to the Lumbar Surgery Expectations Survey (“Expectations Survey”), which addresses multiple aspects of health and well-being, and to compare the relevance of surgeon-selected versus survey-selected Patient-Reported Outcomes Measurement Information System (PROMIS) items to LDS. Methods: In a cross-sectional study, 379 patients with LDS preoperatively completed the Expectations Survey, Numerical Rating Pain Scales, Oswestry Disability Index (ODI), and PROMIS computer-adaptive physical function, pain, and mental health surveys. Expectations Survey scores were compared to PROMs with correlation coefficients (indicating strengths of relationships) and probability values (indicating associations by chance). Surgeons reviewed physical function questions to identify those particularly relevant to LDS. Results: Patients’ mean age was 67 years, 64% were women, and 83% had single-level and 17% had multiple-level LDS. Probability values between the Expectations Survey and PROMs were reliable, but strengths of relationships were only mild to moderate, indicating PROMs did not comprehensively capture the impact of LDS. None of the surgeon-selected PROMIS physical function questions were posed to patients. Conclusion: This cross-sectional study found PROMs to be reliably associated but not strongly correlated with the Expectations Survey, which addresses the whole-patient impact of LDS. New measures that complement PROMIS and ODI should be developed to capture the whole-person effects of LDS and permit attribution of LDS treatments to overall health.

Background: Controversies remain on the best surgical approaches for unilateral total hip arthroplasty (THA). There are little data on simultaneous bilateral THA via direct anterior approach (SimBDAA-THA) or posterolateral approach (SimBPA-THA). Purpose: We sought to assess differences in perioperative outcomes and early medical and surgical complications between SimBDAA-THA and SimBPA-THA. Methods: This retrospective study involved patients who underwent either SimBDAA-THA in a supine position (n = 73) or SimBPA-THA in a lateral position (n = 162) at our institution from January 2015 to November 2021. The 2 groups were compared in terms of clinical and demographic characteristics, surgical parameters, and complications during 6-months of follow-up. Results: There were no differences in clinical and demographic characteristics between the 2 groups prior to surgery. Simultaneous bilateral THA via direct anterior approach significantly shortened the length of both the operation (117.50 ±19.42 vs 143.97 ± 32.20 min) and the hospitalization (140.64 ± 43.22 vs 156.24 ± 56.64 h) but increased perioperative loss of hemoglobin (3.28 ± 1.01 vs 3.21 ± 2.26 g/dL). There were no significant differences between the two groups in transfusion rate; levels of interleukin-6, C-reactive protein or creatine kinase; or complications. Conclusion: This retrospective study of patients at a single institution found minimal differences in perioperative outcomes or early medical and surgical complications between SimBDAA-THA and SimBPA-THA except operative time and length of hospitalization. Larger studies with longer follow-up should be conducted to identify whether a direct anterior approach is superior to a posterolateral one.

Background: Immunosuppressive agents inhibit COVID-19 vaccine antibody (Ab) responses in patients with systemic rheumatic diseases. Rituximab may fully block Ab responses when B cells become undetected. The effect of detected but low number of B cells due to treatment with a B-cell agent (belimumab and/or rituximab) has not been established. Purpose: We sought to examine whether there is an association between a low number of B cells due to treatment with belimumab and/or rituximab and impaired primary COVID-19 vaccination spike Ab responses in patients with systemic rheumatic diseases. Methods: We retrospectively examined Ab responses to COVID-19 vaccinations, especially in relation to B-cell counts after treatment with belimumab and/or rituximab, in 58 patients with systemic rheumatic diseases: 22 on and 36 not on B-cell agents. We used Kruskal-Wallis and Mann-Whitney U tests for comparison of Ab values between the groups and Fisher exact test for relative risk calculations. Results: Median (interquartile range) postvaccination Ab responses were lower in patients on versus those not on B-cell agents: 3.91 (0.77–20.00) versus 20.00 (14.32–20.00), respectively. Among patients on belimumab and/or rituximab, Ab responses of less than 25% of the assay’s upper limit were exclusively observed in those with B-cell counts lower than 40/µL. Patients with B-cell counts lower than 40/µL exhibit a relative risk of 6.092 (95% CI: 2.75–14.24) for Ab responses of less than 25% of the upper limit compared with patients not on B-cell agents. This relative risk remained significant, even after excluding patients with undetected B cells. Conclusion: This retrospective study found an association between low B-cell counts (less than 40/µL) and decreased Ab responses to primary COVID-19 vaccination in patients with systemic rheumatic diseases treated with belimumab and/or rituximab. Despite the small number of patients studied, these findings add to the accumulating evidence on the importance of B-cell count in predicting spike Ab responses to COVID-19 vaccination.

Background: Pelvic tilt (PT) is described as the pelvic orientation along the transverse axis, yet 4 PT definitions were established based on radiographic landmarks: anterior pelvic plane (PT_a), the center of femoral heads to sacral plate (PT_m), pelvic outlet (PT_h), and sacral slope (SS). These landmarks quantify a similar concept, yet understanding of their relationships is lacking, and their differences are sometimes ignored. Purpose: This study aimed to examine the correlations and differences of PT definitions for education and research purposes. Methods: This study reviewed 105 sagittal pelvic radiographs of patients (68 men and 37 women) awaiting hip surgery at a single clinic. Hip hardware and spine pathologies were examined for subgroup analysis. Two observers annotated 4 PTs in a gender-dependent manner and repeated it after 6 months. The linear regression model and intraclass correlation coefficient (ICC) were applied with a 95% confidence interval. Results: The SS showed no correlation to the other 3 PT definitions, except for females in the hip hardware subgroup (n = 17). PT_m demonstrated very strong linear correlation to PT_h (r > 0.9) under the linear model PT_m = 0.951 × PT_h – 68.284. Conclusion: The PT_m and PT_h can be calculated from each other under a simple linear regression equation, which enables comparisons between them. SS presented poor correlations to the other PT parameters, except for the female subgroup with hip implant that required further analysis; PT_a-related comparisons showed high anatomical variations between patients.

Background: With the rise of social media and other web-based platforms, there has been a shift in how medical research findings are disseminated. Questions/Purposes: We sought to investigate how often orthopedic surgeons use different knowledge-seeking methods and how confident they were in their ability to stay up-to-date. Methods: We distributed a 23-question survey to 120 orthopedic surgeons employed at a single tertiary-care metropolitan orthopedic hospital. The survey collected the surgeons’ use of reference managers, RSS feeds, and preferred methods of staying up-to-date. Respondents were asked to report the number of hours they spent staying up-to-date per week and their success with keeping up with orthopedic specialty literature. Results: A total of 85 physicians responded (median age, 52 years); 83% of respondents who spent 3 or more hours a week in keeping up-to-date with the literature said they felt successful in doing so, while 40% of participants who spent less than 1 hour a week said they felt successful. Fifty-five percent of surgeons under the median age used social media, while only 29% of surgeons over the median age used social media. Conclusions: This survey suggests that spending only 1 to 2 hours per week was enough to make the orthopedic surgeons we surveyed feel confident that they were keeping up with the literature in their specialty. These findings also suggest that it may be more important for surgeons to choose a convenient method of literature review that will enable them to maximize time spent reading, rather than attempting to use any one source.

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.

Background: Prolonged length of stay (LOS) after a hip fracture is associated with increased mortality. Purpose: We sought to create a model to predict prolonged LOS in elderly Chilean patients with hip fractures managed during the COVID-19 pandemic. Methods: Employing an official database, we created an artificial neural network (ANN), a computational model corresponding to a subset of machine learning, to predict prolonged LOS (≥14 days) among 2686 hip fracture patients managed in 43 Chilean public hospitals during 2020. We identified 18 clinically relevant variables as potential predictors; 80% of the sample was used to train the ANN and 20% was used to test it. The performance of the ANN was evaluated via measuring its discrimination power through the area under the curve of the receiver operating characteristic curve (AUC-ROC). Results: Of the 2686 patients, 820 (30.2%) had prolonged LOS. In the training sample (2,125 cases), the ANN correctly classified 1,532 cases (72.09%; AUC-ROC: 0.745). In the test sample (561 cases), the ANN correctly classified 401 cases (71.48%; AUC-ROC: 0.742). The most relevant variables to predict prolonged LOS were the patient’s admitting hospital (relative importance [RI]: 0.11), the patient’s geographical health service providing health care (RI: 0.11), and the patient’s surgery being conducted within 2 days of admission (RI: 0.10). Conclusions: Using national-level big data, we developed an ANN that predicted with fair accuracy prolonged LOS in elderly Chilean patients with hip fractures during the COVID-19 pandemic. The main predictors of a prolonged LOS were unrelated to the patient’s individual health and concerned administrative and organizational factors.

Background: The orthopedic surgery fellowship match process is associated with substantial stress and expense, yet the optimal number of interviews for fellowships to offer has not been evaluated. Purpose: We sought to evaluate the number of orthopedic surgery fellowship interviews given and construct a model to determine the appropriate number of interviews to offer based on specialty and program size. Methods: We conducted a retrospective study of 6 orthopedic fellowship specialties; data were obtained from San Francisco Match and covered the 5-year period from 2014 to 2018. The orthopedic fellowship subspecialties included adult reconstruction/oncology, foot and ankle, pediatrics, spine, sports medicine, and trauma. We excluded shoulder and elbow (less than 5 years of data) and hand and upper extremity (alternative matching process). Parameters included number of programs, number of spots per program, number of ranked applicants per program (mean ± SD), and difference in number of interviews offered and ranked applicants per program (mean ± SD). Multiple regression analysis was used to create an equation for determining the optimal number of interviews for the programs. Results: Of 1377 orthopedic fellowship programs analyzed, 1370 (99.50%) conducted interviews beyond the number of ranked applicants. Programs ranked an overall mean of 20.10 ± 10.17 applicants with an overall mean of 11.60 ± 8.62 additional interviews offered. Sports medicine had the highest mean ranked applicants (23.21 ± 9.77) and pediatrics had the lowest mean ranked applicants (15.74 ± 7.76). The most additional interviews were given in adult reconstruction (14.80 ± 9.92) and the least were given in pediatrics (8.32 ± 7.17). The predictive equation was reported as Y = β₁x1 + β₂x2 (Y = ranked applicants, x1 = spots open, and x2 = last rank). Conclusion: Programs in 6 orthopedic subspecialties in the fellowship match process appear to consistently offer more interviews than necessary. We have developed a model to help programs predict the optimal number of fellowship applicants to interview. Future studies need to validate the model, especially with anticipated increases of the virtual interview format.

Background: Retired surgeons often have limited opportunities to disseminate their wisdom and expertise in a structured manner to their younger colleagues. In addition, when asked to reflect on their personal and professional lives, many physicians say they wish they had done something differently. The extent to which this is true of retired orthopedic surgeons is not known. Purpose: We sought to determine the percentage of retired orthopedic surgeons who say that they would like to have changed something in their life/career and delineate the most commonly desired changes. Methods: We conducted a cross-sectional study of retired orthopedic surgeons, by emailing a Qualtrics survey to 5864 emeritus members of the American Academy of Orthopaedic Surgeons (AAOS), with 1 initial email invitation in April 2021 followed by 2 reminders in May 2021. The survey employed a branching logic, with up to 16 questions designed to determine whether they would have done anything differently in their life/career. Results: The survey was completed by 1165 of 5864 emeritus AAOS members, for a response rate of nearly 20%. The 3 most represented surgical subspecialties were general orthopedics, adult reconstruction, and hand and upper extremity surgery. Respondents’ average age was 74.9 years and age at retirement was 67.8 years; nearly half worked part-time before retiring. More than 80% of the participants said that they had retired at the appropriate time, and 28.5% said they wished they had done something differently. The wished-for changes most often noted were spending more time with family, spending more time on personal wellness, and selecting better practice partners. Conclusion: The results of our survey of retired orthopedic surgeons show that while most were satisfied with their lives and careers, some had regrets. These findings suggest that there may be factors in the work lives of current surgeons that could be altered to reduce regret. Further study is warranted.

At the cornerstone of the pelvis and spine, the sacrum may be fractured in patients of all ages. Sacral fractures range from high-energy injuries, with mortality rates of up to 18%, to low-energy insufficiency fractures. The intricate geometry of the sacrum, the breadth of morphotypes, and the presence of congenital anomalies all can complicate the treatment of these fractures. Agreement on the surgical indications for these injuries is limited. This narrative review aims to update orthopedic surgeons on the clinical evaluation and the non-surgical and surgical management of these fractures.

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.