Registry Data Show Complication Rates and Cost in Revision Hip Arthroplasty.

BACKGROUND: Revision total hip arthroplaty (rTHA) places a burden on patients, surgeons, and health care systems because outcomes and costs are less predictable than primary THA. The purpose of this study was to define indications and treatments for rTHA, quantify risk for readmissions, and evaluate the economic impacts of rTHA in a hospital system. METHODS: The arthroplasty database of a hospital system was queried to generate a retrospective cohort of 793 rTHA procedures, performed on 518 patients, from 2017 to 2019 at 27 hospitals. Surgeons performed chart reviews to classify indication and revision procedure. Demographics, lengths of stay, discharge dispositions, and readmission data were collected. Analyses of direct costs were performed and categorized by revision type. RESULTS: Totally, 46.3% of patients presented for infection. Patients presenting for infection were 5.6 times more likely to have repeat rTHA than aseptic patients. Septic cases (4.3 days) had longer length of stay than aseptic ones (2.4) (P < .0001). However, 31% of patients discharged to a skilled nursing facility. Direct costs were greatest for a two-stage exchange ($37,642) and lowest for liner revision ($8,979). Septic revisions ($17,696) cost more than aseptic revisions ($11,204) (P < .0001). The 90-day readmission rate was 21.8%. Septic revisions had more readmissions (13.5%) than aseptic revisions (8.3%). CONCLUSIONS: Hip revisions, especially for infection, have an increased risk profile and create a major economic impact on hospital systems. Surgeons may use these data to counsel patients on risks of rTHA and advocate for improved reimbursement for the care of revision patients.

Designing a large-scale track-based monitoring program to detect changes in species distributions in arid Australia.

Monitoring trends in animal populations in arid regions is challenging due to remoteness and low population densities. However, detecting species' tracks or signs is an effective survey technique for monitoring population trends across large spatial and temporal scales. In this study, we developed a simulation framework to evaluate the performance of alternative track-based monitoring designs at detecting change in species distributions in arid Australia. We collated presence-absence records from 550 2-ha track-based plots for 11 vertebrates over 13 years and fitted ensemble species distribution models to predict occupancy in 2018. We simulated plausible changes in species' distributions over the next 15 years and, with estimates of detectability, simulated monitoring to evaluate the statistical power of three alternative monitoring scenarios: (1) where surveys were restricted to existing 2-ha plots, (2) where surveys were optimized to target all species equally, and (3) where surveys were optimized to target two species of conservation concern. Across all monitoring designs and scenarios, we found that power was higher when detecting increasing occupancy trends compared to decreasing trends owing to the relatively low levels of initial occupancy. Our results suggest that surveying 200 of the existing plots annually (with a small subset resurveyed twice within a year) will have at least an 80% chance of detecting 30% declines in occupancy for four of the five invasive species modeled and one of the six native species. This increased to 10 of the 11 species assuming larger (50%) declines. When plots were positioned to target all species equally, power improved slightly for most compared to the existing survey network. When plots were positioned to target two species of conservation concern (crest-tailed mulgara and dusky hopping mouse), power to detect 30% declines increased by 29% and 31% for these species, respectively, at the cost of reduced power for the remaining species. The effect of varying survey frequency depended on its trade-off with the number of sites sampled and requires further consideration. Nonetheless, our research suggests that track-based surveying is an effective and logistically feasible approach to monitoring broad-scale occupancy trends in desert species with both widespread and restricted distributions.

Treatment of an Acromial Stress Fracture After Reverse Total Shoulder Arthroplasty With Teriparatide: A Case Report.

CASE: A 78-year-old woman who underwent reverse total shoulder arthroplasty (RTSA) for proximal humerus fracture developed a Type-3 acromial stress fracture, resulting in increased pain and decreased function 9 months post-op. She was managed nonoperatively with adjunctive teriparatide (FORTEO), and after a 4-month course, she had regained excellent motion and achieved union. CONCLUSION: Teriparatide is a viable adjunct in treating patients nonoperatively with acromial stress fractures after RTSA.

Radiographic Study of Humeral Stem in Shoulder Arthroplasty After Lesser Tuberosity Osteotomy or Subscapularis Tenotomy.

Lesser tuberosity osteotomy (LTO) and subscapularis tenotomy (ST) are used for takedown of the subscapularis during shoulder arthroplasty. LTO offers the theoretical but unproven benefit of improved healing and function of the subscapularis. However, humeral stem subsidence and loosening may be greater when osteotomy is performed, which may compromise functional outcomes. Our hypothesis is that no difference in proximal collar press-fit humeral stem subsidence or loosening exists, with no impairment of functional outcomes using the LTO technique. Radiographs of 39 shoulders from 35 patients who underwent shoulder arthroplasty with a minimum of 1 year of radiographic follow-up were included in the study cohort. All patients received the same press-fit implant (Bigliani-Flatow; Zimmer Biomet). We collected data including demographic information; radiographic measurements, including humeral-acromial distance (HAD); subsidence; subluxation index; the presence of lucent lines >2 mm; and functional outcome scores using the Western Ontario Osteoarthritis of the Shoulder Index, the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire, and the Constant score. Subsidence was 2.8 ± 3.1 mm for LTO vs 2.5 ± 3.1 mm for ST (P = .72). HAD did not differ between the LTO and ST groups preoperatively (9.5 ± 2.4 mm vs 10.9 ± 2.7 mm, P = .11). The first postoperative and final follow-up films for HAD for the LTO and ST groups showed a statistically significant difference (first postoperative film, 11.9 ± 3.7 mm vs 15.9 ± 4.5 mm, P = .005; final follow-up film, 11.8 ± 3.2 mm vs 14.5 ± 3.9 mm, P = .03). We identified no differences in subsidence, lucent lines >2 mm, posterior subluxation, and Constant, and DASH functional outcome scores for patients undergoing total shoulder arthroplasty via the LTO vs ST techniques with the same proximal collar press-fit humeral stem at short-term follow-up.

Necrotizing Sweet Syndrome of the Upper Extremity After Elective Hand Surgery.

Sweet syndrome, or acute febrile neutrophilic dermatosis, is a systemic disease process mainly characterized by hyperpyrexia and skin lesions. A newly described entity, necrotizing Sweet syndrome, is a severe and locally aggressive dermatological condition that clinically and histopathologically resembles a necrotizing soft tissue infection. It is characterized by pathergy, a nonspecific inflammatory response to cutaneous trauma resulting in a propagation of the disease. In contrast to a necrotizing infection, this condition responds to systemic steroids. A high clinical suspicion is required in order to distinguish a necrotizing polymicrobial infection from noninfectious necrotizing Sweet syndrome. We present a case following elective hand surgery.

Rabbit biocontrol and landscape-scale recovery of threatened desert mammals.

Funding for species conservation is insufficient to meet the current challenges facing global biodiversity, yet many programs use expensive single-species recovery actions and neglect broader management that addresses threatening processes. Arid Australia has the world's worst modern mammalian extinction record, largely attributable to competition from introduced herbivores, particularly European rabbits (Oryctolagus cuniculus) and predation by feral cats (Felis catus) and foxes (Vulpes vulpes). The biological control agent rabbit hemorrhagic disease virus (RHDV) was introduced to Australia in 1995 and resulted in dramatic, widespread rabbit suppression. We compared the area of occupancy and extent of occurrence of 4 extant species of small mammals before and after RHDV outbreak, relative to rainfall, sampling effort, and rabbit and predator populations. Despite low rainfall during the first 14 years after RHDV, 2 native rodents listed by the International Union for Conservation of Nature (IUCN), the dusky hopping-mouse (Notomys fuscus) and plains mouse (Pseudomys australis), increased their extent of occurrence by 241-365%. A threatened marsupial micropredator, the crest-tailed mulgara (Dasycercus cristicauda), underwent a 70-fold increase in extent of occurrence and a 20-fold increase in area of occupancy. Both bottom-up and top-down trophic effects were attributed to RHDV, namely decreased competition for food resources and declines in rabbit-dependent predators. Based on these sustained increases, these 3 previously threatened species now qualify for threat-category downgrading on the IUCN Red List. These recoveries are on a scale rarely documented in mammals and give impetus to programs aimed at targeted use of RHDV in Australia, rather than simply employing top-down threat-based management of arid ecosystems. Conservation programs that take big-picture approaches to addressing threatening processes over large spatial scales should be prioritized to maximize return from scarce conservation funding. Further, these should be coupled with long-term ecological monitoring, a critical tool in detecting and understanding complex ecosystem change.

Musculoskeletal Medicine Is Underrepresented in the American Medical School Clinical Curriculum.

BACKGROUND: Musculoskeletal (MSK) conditions are common, and their burden on the healthcare system is increasing as the general population ages. It is essential that medical students be well prepared to evaluate and treat MSK disorders in a confident manner as they enter the workforce. Recent studies and the American Association of Medical Colleges have raised concern that medical schools may not give sufficient instruction on this topic. Other authors have shown that preclinical instruction has increased over the past decade; however, it is unclear if required clinical instruction also has followed that trend. QUESTIONS/PURPOSES: The purposes of this study were: (1) to assess the presence and duration of required or selective instruction in a MSK medicine specialty within the clinical years of undergraduate medical education; and (2) to assess the current state of requirements of clinical clerkships or rotations in other surgical and nonsurgical fields for comparison with the initial findings. METHODS: The web sites of all 141 US medical schools were assessed to determine the content of their clinical curricula for the 2014-2015 academic year; five were excluded because they had not yet had a graduating class by the conclusion of the 2014-2015 academic year. Complete information on required rotations was obtained through the schools' web sites for all 136 (100%) medical schools. For selective experience during the surgery clerkships, complete information was available for 130 of the remaining 136 (96%) web sites. RESULTS: Mean (in weeks, ± SD) duration of core clerkships were as follows: internal medicine (10 ± 2), surgery (8 ± 2), pediatrics (7 ± 1), obstetrics/gynecology (6 ± 1), and psychiatry (5 ± 1). Other common required clerkships were: family medicine (required in 96% [131 of 136] of schools, mean duration of 6 ± 2 weeks), neurology (81% [110], 4 ± 1), and emergency medicine (55% [75], 3 ± 1). Required MSK instruction, at a mean of 2 ± 1 weeks, was only present in 15% (20 of 136) of medical schools. In addition, clinical MSK instruction was offered as a selective (eg, students pick from a selection of subspecialties such as orthopaedics, plastics, or urology during a general surgery clerkship) in 34% (44 of 130) of all medical schools. This is less than other non-core specialties: geriatrics/ambulatory care (required in 40% [54 of 136] of schools, mean duration of 3 ± 1 weeks), critical care (30% [41], mean of 3 ± 1 weeks), radiology (26% [35], mean of 3 ± 1 weeks), anesthesiology (23% [31], mean of 2 ± 1 weeks), and other surgical subspecialties (19% [26], mean of 3 ± 1weeks). CONCLUSIONS: Traditional core clerkships continue to be well represented in the clinical years, whereas three newer specialties have gained a larger presence: family medicine, neurology, and emergency medicine; these comprise the "big eight" of clinical clerkships. Given the high prevalence and burden of MSK disorders, required experience in MSK medicine continues to be underrepresented. Further discussion at a national level is needed to determine appropriate representation of MSK medicine specialties during the clinical years.

Parathyroid hormone 1-34 enhances extracellular matrix deposition and organization during flexor tendon repair.

Parathyroid hormone (PTH) 1-34 is known to enhance fracture healing. Tendon repair is analogous to bone healing in its dependence on the proliferation and differentiation of mesenchymal stem cells, matrix formation, and tissue remodeling.(1,2,3) We hypothesized that PTH 1-34 enhances tendon healing in a flexor digitorum longus (FDL) tendon repair model. C57Bl/6J mice were treated with either intraperitoneal PTH 1-34 or vehicle-control (PBS). Tendons were harvested at 3-28 days for histology, gene expression, and biomechanical testing. The metatarsophalangeal joint range of motion was reduced 1.5-2-fold in PTH 1-34 mice compared to control mice. The gliding coefficient, a measure of adhesion formation, was 2-3.5-fold higher in PTH 1-34 mice. At 14 days post-repair, the tensile strength was twofold higher in PTH 1-34 specimens, but at 28 days there were no differences. PTH 1-34 mice had increased fibrous tissue deposition that correlated with elevated expression of collagens and fibronectin as seen on quantitative PCR. PTH 1-34 accelerated the deposition of reparative tissue but increased adhesion formation.

Factors impacting musculoskeletal knowledge and clinical confidence in graduating medical students.

BACKGROUND: Despite the prevalence of musculoskeletal disorders, the degree to which medical schools are providing students with the knowledge and confidence to treat these problems is unclear. This study evaluated the factors that impact musculoskeletal knowledge and clinical confidence among fourth-year medical students. METHODS: Over a three-year period, 253 fourth-year medical students participated in the study at a single institution. Musculoskeletal knowledge was evaluated using a National Board of Medical Examiners' musculoskeletal medicine subject examination. Factors analyzed included sex, class year, musculoskeletal elective experience, duration of musculoskeletal elective, career choice, and musculoskeletal curriculum satisfaction. RESULTS: The participation rate was 95%. The mean National Board of Medical Examiners' musculoskeletal assessment score (and standard deviation) was 70.7 ± 9.5 points for all fourth-year medical students. Taking a musculoskeletal elective significantly increased knowledge (p < 0.001) but not clinical confidence. Increased satisfaction with how musculoskeletal medicine was taught was associated with increased clinical confidence (p < 0.001). No significant differences were seen if students were going into musculoskeletal medicine or primary care for either musculoskeletal knowledge or clinical confidence. Multivariate analysis of musculoskeletal knowledge found that taking a musculoskeletal elective for two weeks led to an increase of 6 points (from a possible 100 points) in the National Board of Medical Examiners' subject examination scores. CONCLUSIONS: This study reveals that participation in a clinical elective is the only factor that led to a significant increase in musculoskeletal knowledge in fourth-year medical students. A two-week clinical elective can be sufficient time to have an impact on musculoskeletal knowledge, but it alone does not increase clinical confidence. Further studies are needed to determine how to improve musculoskeletal clinical confidence.

Simple overlay device for determining radial head and neck height.

BACKGROUND: The purpose of this study was to test the hypothesis that a simple overlay device can be used on radiographs to measure radial head and neck height. MATERIALS AND METHODS: Thirty anteroposterior elbow radiographs from 30 patients with a clinical diagnosis of lateral epicondylitis were examined to measure radial head and neck height. Three methods using different points along the bicipital tuberosity as a landmark were used. Method 1 used the proximal end of the bicipital tuberosity, method 2 used the most prominent point of the bicipital tuberosity, and method 3 used a simple overlay device (SOD) template that was aligned with anatomic reference points. All measurements were performed three times by three observers to determine interobserver and intraobserver reliability. RESULTS: Intraclass correlation coefficients revealed higher interobserver and intraobserver correlations for the SOD template method than for the other two methods. The 95% limits of agreement between observers were markedly better (-1.8 mm to +1.0 mm) for the SOD template method than for the proximal point method (-3.8 mm to +3.4 mm) or the prominent point method (-5.9 mm to +4.9 mm). CONCLUSIONS: We found that the SOD template method was reliable for assessing radial head and neck height. It had less variability than other methods, its 95% limit of agreement being less than 2 mm. This method could be helpful for assessing whether or not the insertion of a radial head prosthesis has resulted in over-lengthening of the radius.

Contribution of the supraspinatus to the external rotator lag sign: kinematic and electromyographic pattern in an in vivo model.

HYPOTHESIS: The external rotation lag sign (ERLS) is a test designed to assess the integrity of the supraspinatus (SSP) and infraspinatus tendons. This study intends to determine the electromyographic pattern of shoulder girdle muscles during a series of ERLS tasks conducted at full adduction and 20 degrees of elevation to figure out the better way to perform the test. The second aim is to assess the final contribution of the SSP to the ERLS by measuring the amount of lag after an SSP block induced by botulinum toxin. MATERIALS AND METHODS: Ten subjects with healthy shoulders were examined by a series of five ERLS trials at full adduction and 20 degrees of elevation in the scapular plane. Surface and intramuscular electromyographic activity of the shoulder girdle muscles was recorded and normalized against either the mean activity of all the muscles or the peak activity. The lag was simultaneously measured by an infrared optoelectronic system before and after the selective block of the SSP muscle. RESULTS: The SSP contributed 20% of the electrical activities during the ERLS, which was found to be significantly greater than the contributions of the other shoulder girdle muscles, except for the infraspinatus. The selective block of the SSP caused a lag of 4 degrees in all 10 shoulders at 20 degrees but no increase in lag at 0 degrees of elevation. CONCLUSIONS: The ERLS is potentially able to detect an isolated SSP tear if the test is performed correctly (20 degrees of abduction). The deltoid and biceps muscles are almost silent during the test, limiting confounding factors.

Arthroscopic removal of the failed silicone radial head prosthesis.

Although silicone radial head arthroplasty has been successful in many patients, it has been associated with complications such as fractures of the prosthesis and silicone synovitis. Synovectomy and removal of the failed silicone radial head, with or without reimplantation of a metallic radial head, is indicated in such complications. In an effort to perform minimally invasive surgery, we performed arthroscopic removal of the silicone head combined with synovectomy in a series of such patients. The silicone prostheses were cut into two or three pieces and then removed. After a median follow up of 26 months, all patients reported excellent pain relief and there were no residual loose bodies. Removal of a failed silicone radial head can be successfully performed arthroscopically. This arthroscopic technique has the advantage of being minimally invasive and can be combined with other procedures including capsulectomy, if necessary.

The myofibrillar protein, projectin, is highly conserved across insect evolution except for its PEVK domain.

All striated muscles respond to stretch by a delayed increase in tension. This physiological response, known as stretch activation, is, however, predominantly found in vertebrate cardiac muscle and insect asynchronous flight muscles. Stretch activation relies on an elastic third filament system composed of giant proteins known as titin in vertebrates or kettin and projectin in insects. The projectin insect protein functions jointly as a "scaffold and ruler" system during myofibril assembly and as an elastic protein during stretch activation. An evolutionary analysis of the projectin molecule could potentially provide insight into how distinct protein regions may have evolved in response to different evolutionary constraints. We mined candidate genes in representative insect species from Hemiptera to Diptera, from published and novel genome sequence data, and carried out a detailed molecular and phylogenetic analysis. The general domain organization of projectin is highly conserved, as are the protein sequences of its two repeated regions-the immunoglobulin type C and fibronectin type III domains. The conservation in structure and sequence is consistent with the proposed function of projectin as a scaffold and ruler. In contrast, the amino acid sequences of the elastic PEVK domains are noticeably divergent, although their length and overall unusual amino acid makeup are conserved. These patterns suggest that the PEVK region working as an unstructured domain can still maintain its dynamic, and even its three-dimensional, properties, without the need for strict amino acid conservation. Phylogenetic analysis of the projectin proteins also supports a reclassification of the Hymenoptera in relation to Diptera and Coleoptera.

Expresión diferencial de proteínas cardiacas en ratas diabéticas tipo Sprague-Dawley / Differential heart protein expression in diabetic type Sprague-Dawley rats

Se purificaron proteínas cardiacas a partir de ratas diabéticas y sanas de tipo Sprague-Dawley. Las proteínas fueron fraccionadas por medio de gel de electroforesis de dos dimensiones (2D-PAGE). La separación resultante fue visualizada por tinción con Coomassie azul. Luego de ser convertidas en imagen digital, las proteínas del grupo diabético y del grupo control fueron comparadas y correlacionadas para determinar los niveles de expresión diferenciada. Sesenta de las ciento ochenta proteínas en el gel fueron removidas y digeridas en fragmentos pequeños de péptidos, los cuales se analizaron por medio de espectrometría de masas para determinar la estructura primaria de los péptidos resultantes (secuencia de los aminoácidos). Esta información se registró en una base de datos (http://www.ncbi.nlm.nih.gov/) para determinar la identidad de las proteínas precedentes a los péptidos. Se determinó la identidad de las proteínas expresadas diferencialmente en el tejido cardiaco de ambos grupos; se encontraron varias proteínas expresadas en diferentes niveles a los normales cuando se analizaron los corazones de ratas diabéticas, incluyendo fosfatasa de tiroxina (PTP, Q60998), receptores de lipoproteínas de muy baja densidad (VLDL-R, P98156), perioxidasa de glutation (PHGPx, O70325), transferasa de serina hidroxilamina (SHMT, P50431), adenylyl cyclasa proteína 1 asociada (CAP1, P40124) y teletonina (TELT, O70548).

Cardiac proteins were isolated from diabetic and wild type Sprague-Dawley rats, then fractionated by two dimensional gel electrophoresis (2D-PAGE) using isoelectric focusing and molecular weight. The resulting protein spots were stained to facilitate detection. After being converted into a digital image, the proteins on the diabetic and wild type gels were matched to each other then compared to determine levels of expression. Sixty of the one hundred and eighty proteins on the gel were removed and digested to produce peptide fragments, which were analyzed by mass spectrometry to determine their amino acid sequence. This information was entered into a protein database (http://www.ncbi.nlm.nih.gov/) to determine the identity of the corresponding proteins. The identity of proteins differentially expressed in cardiac tissue of both groups was determined: several proteins were found to be expressed at different levels than normal in the hearts of diabetic rats, including protein tyrosine phosphatase (PTP, Q60998), very low-density lipoprotein receptor (VLDL-R, P98156), glutathione peroxidase (PHGPx, O70325), serine hydroxymethyl transferase (SHMT, P50431), adenylyl cyclase-associated protein 1 (CAP1, P40124), and telethonin (TELT, O70548).

In indirect flight muscles Drosophila projectin has a short PEVK domain, and its NH2-terminus is embedded at the Z-band.

Insect indirect flight muscles (IFM) contain a third filament system made up of elastic connecting or C-filaments. The giant protein projectin is the main, if not the only, component of these structures. In this study we found that projectin is oriented within the IFM sarcomere with its NH2-terminus embedded in the Z-bands. We demonstrate that this protein has an elastic region that can be detected by the movement of specific epitopes following stretch. One possible elastic region is the PEVK-like domain located close to the NH2-terminus. The amino acid length of this region is short, and 52% of its residues are P, E, V or K. We propose a model in which projectin extends from the Z-band to the lateral borders of the A-band. The PEVK-like domain and a series of Ig domains spanning the intervening I-band may provide the elastic properties of projectin.

Assembly of the giant protein projectin during myofibrillogenesis in Drosophila indirect flight muscles.

BACKGROUND: Projectin is a giant modular protein of Drosophila muscles and a key component of the elastic connecting filaments (C-filaments), which are involved in stretch activation in insect Indirect Flight Muscles. It is comparable in its structure to titin, which has been implicated as a scaffold during vertebrate myofibrillogenesis. METHODS: We performed immunofluorescence studies on Drosophila pupal tissue squashes and isolated myofibrils to identify the pattern of appearance and assembly for projectin and several other myofibrillar proteins, using both wild type and mutant fly stocks. RESULTS AND CONCLUSIONS: In the first step of assembly, projectin immunolocalization appears as random aggregates colocalizing with alpha-actinin, kettin and Z(210), as well as, F-actin. In the second step of assembly, all these proteins become localized within discrete bands, leading ultimately to the regularly spaced I-Z-I regions of myofibrils. This assembly process is not affected in myosin heavy chain mutants, indicating that the anchoring of projectin to the thick filament is not essential for the assembly of projectin into the developing myofibrils. In the actin null mutation, KM88, the early step involving the formation of the aggregates takes place despite the absence of the thin filaments. All tested Z-band proteins including projectin are present and are colocalized over the aggregates. This supports the idea that interactions of projectin with other Z-band associated proteins are sufficient for its initial assembly into the forming myofibrils. In KM88, though, mature Z-bands never form and projectin I-Z-I localization is lost at a later stage during pupal development. In contrast, treatment of adult myofibrils with calpain, which removes the Z-bands, does not lead to the release of projectin. This suggests that after the initial assembly with the Z-bands, projectin also establishes additional anchoring points along the thick and/or thin filaments. In conclusion, during pupation the initial assembly of projectin into the developing myofibril relies on early association with Z-band proteins, but in the mature myofibrils, projectin is also held in position by interactions with the thick and/or the thin filaments.