Rates of interlock screw back-out are high with the retrograde femoral nailing advanced system for distal femur fractures.

PURPOSE: The retrograde femoral nailing advanced (RFNA) system (DePuy synthes) is a commonly used implant for the fixation of low distal femur and periprosthetic fractures. There is concern that the rate of distal interlock screw back-out may be higher for the RFNA compared to other nails (ON). The purpose of this study was to evaluate the incidence of interlock screw back-out and associated screw removal for RFNA versus ON, along with associated risk factors. METHODS: A retrospective comparative study of patients who underwent retrograde nailing for a distal femur fracture at an academic level one trauma center was performed. The incidence of distal interlock screw back-out and need for screw removal were compared for RFNA versus a propensity score matched cohort who received other nails. RESULTS: One hundred and ten patients underwent retrograde nailing with the RFNA for a distal femur fracture from 2015 to 2022 (average age: 66, BMI: 32, 52.7% smokers, 54.5% female, 61.8%). There was a significantly higher rate of interlock back-out in the RFNA group compared to the ON (27 patients, 24.5% vs 12 patients, 10.9%, p = 0.01), which occurred 6.3 weeks postoperatively. Screw removal rates for back-out were not significantly different for the RFNA group versus ON (8 patients, 7.3% vs 3 patients, 2.7%, p = 0.12). CONCLUSION: In this retrospective comparative study of distal femur fractures treated with retrograde nailing, the RFNA implant was associated with an increased risk of distal interlock screw back-out compared to other nails.

Concentration of voxelotor in sickle cell disease can be estimated using electrophoresis and high-performance liquid chromatography.

OBJECTIVES: Voxelotor can increase hemoglobin levels in patients living with sickle cell disease (SCD). A clinician who is monitoring voxelotor response may want to know whole-blood voxelotor concentration, but this cannot be measured in most clinical settings. However, voxelotor has been demonstrated to cause "peak splitting" in common methods of hemoglobin measurement such as capillary zone electrophoresis (CZE) and high-performance liquid chromatography (HPLC). We hypothesized that we could use the size of the peak split to estimate the whole-blood concentration. METHODS: Blood from people with SCD was dosed with known concentrations of voxelotor, and multiparameter regression was used to derive the relationship of voxelotor concentration to the degree of peak splitting observed. To validate these equations, 21 patients started on voxelotor at 1500 mg/d had blood samples drawn at days 0, 14, 30, and 60. Samples were sent out for gold standard voxelotor concentration testing. The derived equations were then used to calculate voxelotor concentration. RESULTS: Calculated concentrations correlated strongly with measured concentrations for both CZE (R2 = 0.83, P < .001) and HPLC (R2 = 0.76, P < .001). Voxelotor concentration also had a significant effect on increases in hemoglobin (R2 = 0.40, P < .001). CONCLUSIONS: Thus, peak splitting CZE and HPLC can be used to estimate voxelotor concentration.

Trifocal femur fracture with intracapsular femoral neck, open diaphyseal, and distal complete articular fractures.

We describe a trifocal femur injury with intracapsular femoral neck fracture, diaphyseal fracture with bone loss, and distal complete articular (AO/OTA C type) fracture, an injury rarely described in the literature. Surgical management utilized a not-yet-reported implant combination: screw-side plate device for the intracapsular femoral neck, retrograde nail for the diaphysis, and lag screws plus mini fragment buttress plating for the distal fracture. The patient had uneventful fracture union with no changes in alignment. Given the rarity and complexity of this injury, there is little consensus on surgical technique and implant choice. This case demonstrates a modernized approach that may be useful for surgeons who encounter similar fracture patterns in their practice.

Noisy Delay Denoises Biochemical Oscillators.

Genetic oscillations are generated by delayed transcriptional negative feedback loops, wherein repressor proteins inhibit their own synthesis after a temporal production delay. This delay is distributed because it arises from a sequence of noisy processes, including transcription, translocation, translation, and folding. Because the delay determines repression timing and, therefore, oscillation period, it has been commonly believed that delay noise weakens oscillatory dynamics. Here, we demonstrate that noisy delay can surprisingly denoise genetic oscillators. Specifically, moderate delay noise improves the signal-to-noise ratio and sharpens oscillation peaks, all without impacting period and amplitude. We show that this denoising phenomenon occurs in a variety of well-studied genetic oscillators, and we use queueing theory to uncover the universal mechanisms that produce it.

Treating insomnia in people who are incarcerated: a feasibility study of a multicomponent treatment pathway.

Around 60% of people who are incarcerated have insomnia; 6-10 times more prevalent than the general population. Yet, there is no standardized, evidence-based approach to insomnia treatment in prison. We assessed the feasibility of a treatment pathway for insomnia in a high-secure prison to inform a future randomized controlled trial (RCT) and initial efficacy data for sleep and mental health outcomes. We used a within-participants pre-post design. The stepped-care pathway included: self-management with peer support, environmental aids, and cognitive behavioral therapy for insomnia (CBTi). Assessment measures for insomnia, well-being, mood, anxiety, suicidality, overall health, sleepiness, fatigue, and cognitive functioning were administered at baseline and pathway exit. Feasibility criteria included eligibility to participate, CBTi uptake, and assessment completion. Forty-two adult males who are incarcerated were approached of which 95.2% were eligible. Of those deemed eligible, most participated (36/40, 90.0%). Most who completed baseline completed post-assessments (28/36, 77.8%) and of these, most showed improvements in their subjective sleep (27/28, 96.4%). Large reductions were found from pre- to posttreatment in insomnia severity (d = -1.81, 95% CI: 8.3 to 12.9) and 57.0% reported no clinically significant insomnia symptoms at post-assessment. There was no overall change in actigraphy-measured sleep. Large treatment benefits were found for depression, anxiety, well-being, and cognitive functioning, with a medium benefit on suicidal ideation. The treatment pathway for insomnia in prison was feasible and may be an effective treatment for insomnia in people who are incarcerated, with additional promising benefits for mental health. A pragmatic RCT across different prison populations is warranted. This paper is part of the Sleep and Circadian Health in the Justice System Collection.

Retrograde Intramedullary Nailing Versus Locked Plating for Extreme Distal Periprosthetic Femur Fractures: A Multicenter Retrospective Cohort Study.

OBJECTIVES: To compare clinical and radiographic outcomes after retrograde intramedullary nailing (rIMN) versus locked plating (LP) of "extreme distal" periprosthetic femur fractures, defined as those that contact or extend distal to the anterior flange. DESIGN: Retrospective review. SETTING: Eight academic level I trauma centers. PATIENT SELECTION CRITERIA: Adult patients with periprosthetic distal femur fractures at or distal to the anterior flange (OTA/AO 33B-C[VB1]) treated with rIMN or LP. OUTCOME MEASURES AND COMPARISONS: The primary outcome was reoperation to promote healing or to treat infection (reoperation for elective removal of symptomatic hardware was excluded from this analysis). Secondary outcomes included nonunion, delayed union, fixation failure, infection, overall reoperation rate, distal femoral alignment, and ambulatory status at final follow-up. Outcomes were compared between patients treated with rIMN or LP. RESULTS: Seventy-one patients treated with rIMN and 224 patients treated with LP were included. The rIMN group had fewer points of fixation in the distal segment (rIMN: 3.5 ± 1.1 vs. LP: 6.0 ± 1.1, P < 0.001) and more patients who were allowed to weight-bear as tolerated immediately postoperatively (rIMN: 45%; LP: 9%, P < 0.01). Reoperation to promote union and/or treat infection was 8% in the rIMN group and 16% in the LP group ( P = 0.122). There were no significant differences in nonunion ( P > 0.999), delayed union ( P = 0.079), fixation failure ( P > 0.999), infection ( P = 0.084), or overall reoperation rate ( P > 0.999). Significantly more patients in the rIMN group were ambulatory without assistive devices at final follow-up (rIMN: 35%, LP: 18%, P = 0.008). CONCLUSIONS: rIMN of extreme distal periprosthetic femur fractures has similar complication rates compared with LP, with a possible advantage of earlier return to weight-bearing. Surgeons can consider this treatment strategy in all fractures with stable implants and amenable prosthesis geometry, even extreme distal fractures. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Interfragmentary strain measurement post-fixation to guide intraoperative decision making: a narrative review.

PURPOSE: Interfragmentary strain influences whether a fracture will undergo direct and indirect fracture healing. Orthopedic trauma surgeons modulate strain and create optimal biomechanical environments for specific fracture patterns using fixation constructs. However, objective intraoperative interfragmentary strain measurement does not currently inform fixation strategy in common practice. This review identifies potential methods and technologies to enable intraoperative strain measurement for guiding optimal fracture fixation strategies. METHODS: PubMed, Scopus, and Web of Science were methodologically queried for manuscripts containing terms related to "bone fracture," "strain," "measurement," and "intraoperative." Manuscripts were systematically screened for relevance and adjudicated by three reviewers. Relevant articles describing methods to measure interfragmentary strain intraoperatively were summarized. RESULTS: After removing duplicates, 1404 records were screened initially. There were 49 manuscripts meeting criteria for in-depth review. Of these, four reports were included in this study that described methods applicable to measuring interfragmentary strain intraoperatively. Two of these reports described a method using instrumented staples, one described optical tracking of Kirschner wires, and one described using a digital linear variable displacement transducer with a custom external fixator. CONCLUSION: The four reports identified by this review describe potential methods to quantify interfragmentary strain after fixation. However, further studies are needed to confirm the precision and accuracy of these measurements across a range of fractures and fixation methods. Additionally, described methods require the insertion and likely removal of additional implants into the bone. Ideally, innovations that measure interfragmentary strain intraoperatively would provide dynamic biomechanical feedback for the surgeon to proactively modulate construct stability.

Distal Tibia Apex Posterior Angulation: A Normal Anatomic Variant Related to Hindfoot Alignment With Side-to-Side Symmetry.

OBJECTIVES: The sagittal plane of the distal tibia has not been well-described. This study sought to characterize sagittal plane morphology, determine symmetry from side to side, and identify differences based on hindfoot alignment. METHODS: One hundred twelve bilateral lateral weight-bearing ankle radiographs were retrospectively evaluated (224 ankles). Hindfoot alignment was classified as neutral, planus, or cavus using the Meary angle. The angle between the diaphyseal and distal tibia axes was measured, and the apex location relative to the plafond was recorded. RESULTS: A mean distal tibia apex posterior angulation (DTAPA) of 2.0° (range -2° to 7°, SD = 2.06°) was located 8.0 cm proximal to the plafond. No difference was observed from side to side in DTAPA magnitude (P = 0.36) or location (P = 0.90). Planus alignment was associated with a significantly greater DTAPA (3.05°) as compared with neutral (1.89°) (P = 0.002) and cavus (1.25°) (P < 0.001) alignment. CONCLUSION: The distal tibia has an apex posterior angulation, suggesting that the true anatomic axis of the tibia terminates just posterior to the plafond center. Hindfoot alignment is related to distal tibia morphology. DTAPA symmetry indicates that contralateral imaging can be used to guide reconstruction of patient-specific anatomy and alignment. Knowledge of the DTAPA may help mitigate sagittal malalignment during distal tibia fracture surgery.

Updated Blocking Techniques for Lower Extremity Medullary Nailing: Beyond the Concavity of Deformity.

Modern blocking techniques are useful to achieve anatomic alignment and stable fixation during end-segment nailing. Whether with screws or drill bits, blocking implants can correct both angular and translational deformities. Understanding the biomechanics of blocking implants allows the surgeon to properly plan their placement based on principles rather than dogma. We use case examples to highlight updates in blocking techniques during acute surgical fixation and chronic deformity correction.

Irreducible posterior hip dislocation in the setting of a multifocal displaced pelvic ring injury: A case report.

Case report: Traumatic hip dislocations require prompt diagnosis and reduction to preserve the native joint. The classic irreducible posterior hip fracture-dislocation has been described as an immobile, slightly flexed, and internally rotated hip on physical exam. Classically, this irreducible pattern is associated with an ipsilateral femoral head fracture. The purpose of our report is to present an irreducible posterior hip dislocation with preserved motion in the setting of an unstable pelvic ring injury without associated femoral head pathology. Despite lacking clinical features of an irreducible hip, closed reduction in the emergency and operating rooms was unsuccessful, even after frame application for pelvis stability. Persistent irreducibility necessitated open reduction, where the femoral head was found to be buttonholed through the posterior hip capsule and blocking reduction. Conclusion: A posteriorly dislocated hip with preserved motion in the setting of a concomitant unstable pelvic ring injury may belie the true locked nature of the femoroacetabular dislocation and high suspicion for femoral head incarceration is required. The description of this unique irreducible fracture pattern and the stepwise approach used for reduction may be useful for other surgeons who may encounter similar patterns of injury.

Study of efficacy and longevity of immune response to third and fourth doses of COVID-19 vaccines in patients with cancer: A single arm clinical trial.

Background: Cancer patients show increased morbidity with COVID-19 and need effective immunization strategies. Many healthcare regulatory agencies recommend administering 'booster' doses of COVID-19 vaccines beyond the standard two-dose series, for this group of patients. Therefore, studying the efficacy of these additional vaccine doses against SARS-CoV-2 and variants of concern is of utmost importance in this immunocompromised patient population. Methods: We conducted a prospective single arm clinical trial enrolling patients with cancer that had received two doses of mRNA or one dose of AD26.CoV2.S vaccine and administered a third dose of mRNA vaccine. We further enrolled patients that had no or low responses to three mRNA COVID vaccines and assessed the efficacy of a fourth dose of mRNA vaccine. Efficacy was assessed by changes in anti-spike antibody, T-cell activity, and neutralization activity, which were again assessed at baseline and 4 weeks. Results: We demonstrate that a third dose of COVID-19 vaccine leads to seroconversion in 57% of patients that were seronegative after primary vaccination series. The immune response is durable as assessed by anti-SARS-CoV-2 (anti-S) antibody titers, T-cell activity, and neutralization activity against wild-type (WT) SARS-CoV2 and BA1.1.529 at 6 months of follow-up. A subset of severely immunocompromised hematologic malignancy patients that were unable to mount an adequate immune response (titer <1000 AU/mL) after the third dose and were treated with a fourth dose in a prospective clinical trial which led to adequate immune boost in 67% of patients. Low baseline IgM levels and CD19 counts were associated with inadequate seroconversion. Booster doses induced limited neutralization activity against the Omicron variant. Conclusions: These results indicate that third dose of COVID vaccine induces durable immunity in cancer patients and an additional dose can further stimulate immunity in a subset of patients with inadequate response. Funding: Leukemia Lymphoma Society, National Cancer Institute. Clinical trial number: NCT05016622.

People with cancer have a higher risk of death or severe complications from COVID-19. As a result, vaccinating cancer patients against COVID-19 is critical. But patients with cancer, particularly blood or lymphatic system cancers, are less likely to develop protective immunity after COVID-19 vaccination. Immune suppression caused by cancer or cancer therapies may explain the poor vaccine response. Booster doses of the vaccine may improve the vaccine response in patients with cancer. But limited information is available about how well booster doses protect patients with cancer against COVID-19. Thakkar et al. show that a third dose of a COVID-19 vaccine can induce a protective immune response in half of the patients with cancer with no immunity after the first two doses. In the experiments, Thakkar et al. tracked the immune reaction to COVID-19 booster shots in 106 cancer patients. A third booster dose protected patients for up to four to six months and reduced breakthrough infection rates to low levels. Eighteen patients with blood cancers and severe immune suppression had an inadequate immune response after three doses of the vaccine; a fourth dose boosted the immune response for two-thirds of them, which for some included neutralization of variants such as Omicron. The experiments show that booster doses can increase COVID-19 vaccine protection for patients with cancer, even those who do not respond to the initial vaccine series. Thakkar et al. also show that pre-vaccine levels of two molecules linked to the immune system, (immunoglobin M and the CD19 antigen) predicted the patients' vaccine response, which might help physicians identify which individuals would benefit from booster doses.

Apex posterior angulation of the humerus: A characterization of normal sagittal plane anatomy with implications for surgical fixation.

INTRODUCTION: An understanding of the sagittal plane morphology of the humerus is relevant during surgical fixation of humeral fractures but is not well described in the literature. The purpose of this study was to better characterize the native sagittal plane morphology of the humerus. MATERIALS AND METHODS: 170 patients with uninjured full length lateral humerus radiographs were retrospectively evaluated. The angle between the proximal humeral diaphyseal axis and the distal humeral diaphyseal axis was identified and measured. The proximal axis was defined by two points equidistant from the anterior and posterior cortex 10 mm and 100 mm distal to the metaphyseal flare, and the distal axis by two points at 10 mm and 50 mm proximal to the capitellum/trochlea. The relative location of the center of rotation of angulation (CORA) was calculated as a percentage of humeral length. RESULTS: 114 radiographs were included in the analysis (66 right humeri, 48 left humeri). The average apex posterior angulation was 6.5 +/- 2.9°. The CORA occurred at an average of 80% (SD+/-13%) of the length of the humerus (proximal to distal). Total humeral length and absolute distance to CORA were greater in males compared to females (364 ± 50 mm versus 326 ± 30 mm; p<0.001; 290 ± 68 mm versus 260 ± 48 mm; p=0.003), but there were no significant sex differences with respect to magnitude of the apex posterior angulation (p=0.077) or location of CORA as a percentage of total humeral length (p=0.916). There were no statistically significant associations between age and total humeral length (p=0.056), distance to CORA (p=0.130), location of CORA as percentage of total humeral length (p=0.753), or magnitude of angulation (p=0.075). CONCLUSION: An apex posterior bow consistently exists in the distal one-quarter of the humerus that is consistent across ages and between sexes. This normal anatomic bow is important to recognize to avoid an extension malreduction and has implications for implant fit and contouring.

Traumatic Proximal Femoral Fractures during COVID-19 Pandemic in the US: An ACS NSQIP® Analysis.

In order to determine the impact of COVID-19 on the treatment and outcomes in patients with proximal femoral fracture's (PFF), we analyzed a national US sample. This is a retrospective review of American College of Surgery's (ACS) National Surgical Quality Improvement Program (NSQIP) for patients with proximal femoral fractures. A total of 26,830 and 26,300 patients sustaining PFF and undergoing surgical treatment were sampled during 2019 and 2020, respectively. On multivariable logistic regression, patients were less likely to have 'presence of non-healing wound' (p < 0.001), functional status 'independent' (p = 0.012), undergo surgical procedures of 'hemiarthroplasty'(p = 0.002) and 'ORIF IT, Peritroch, Subtroch with plates and screws' (p < 0.001) and to be 'alive at 30-days post-op' (p = 0.001) in 2020 as compared to 2019. Patients were more likely to have a case status 'emergent', 'loss of ≥10% body weight', discharge destination of 'home' (p < 0.001 for each) or 'leaving against medical advice' (p = 0.026), postoperative 'acute renal failure (ARF)' (p = 0.011), 'myocardial infarction (MI)' (p = 0.006), 'pulmonary embolism (PE)' (p = 0.047), and 'deep venous thrombosis (DVT)' (p = 0.049) in 2020 as compared to 2019. Patients sustaining PFF and undergoing surgical treatment during pandemic year 2020 differed significantly in preoperative characteristics and 30-day postoperative complications when compared to patients from the previous year.

A Single Proximal Interlocking Bolt May Be Sufficient for Retrograde Nailing of Extra-articular Femur Fractures.

OBJECTIVE: To evaluate whether a single proximal interlocking bolt was sufficient during the treatment of extra-articular femur fractures with retrograde medullary nailing. DESIGN: Retrospective comparative study. SETTING: Academic Level 1 trauma center. PATIENTS: The study included 136 patients with extra-articular femur fractures treated with retrograde medullary nailing who met inclusion and follow-up criteria. INTERVENTION: The intervention included surgical treatment for a femur fracture with retrograde medullary nailing, with comparisons made between those treated with a single proximal interlocking (1 IL) bolt and those treated with 2 proximal interlocking bolts (2 IL). MAIN OUTCOME MEASUREMENT: The main outcome measurements were as follows: (1) rate of nonunion and (2) rate of catastrophic implant failure. RESULTS: There was no difference in the rate of nonunion requiring surgical intervention between the 2 groups. There were no catastrophic failures in either group. CONCLUSIONS: A single proximal interlocking bolt may be sufficient when using retrograde nailing for the treatment of extra-articular femur fractures. LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Triceps Surae Lengthening in Foot and Ankle Trauma: A Survey of OTA and AOFAS Members.

Background: The prevalence, indications, and preferred methods for gastrocnemius recession and tendo-Achilles lengthening-grouped as triceps surae lengthening (TSL) procedures-in foot and ankle trauma are supported by a scarcity of clinical evidence. We hypothesize that injury, practice environment, and training heritage are significantly associated with probability of performing adjunctive TSL in the operative management of foot and ankle trauma. Methods: A survey was distributed to members of the American Orthopaedic Foot & Ankle Society and the Orthopaedic Trauma Association. Participants rated how likely they would be to perform TSL at initial management, definitive fixation, and after weightbearing in the presence and absence of a positive Silfverskiöld test in 10 clinical scenarios of closed foot and ankle trauma. Results: A total of 258 surgeons with median 14 years' experience responded. Eighty-five percent reported foot and ankle fellowship training, 24% reported traumatology fellowship training, 13% both, and 4% no fellowship. Ninety-nine percent reported performing TSL with a median 25 TSL procedures per year, 72% open gastrocnemius recession, and 17% percutaneous tendo-Achilles lengthening). Across all scenarios, we observed low overall 8% probability with fair agreement (κ = 0.246) of performing TSL (range, 1% at initial management of an unstable Weber B bimalleolar ankle fracture with negative contralateral Silfverskiöld test to 29% at definitive fixation of tongue-type calcaneus fracture with positive contralateral Silfverskiöld test). Silfverskiöld testing significantly influenced TSL probability at all time points. University of Washington training (ß = 1.5, P = .007) but not trauma vs foot fellowship training, years in practice, academic practice, urban setting, or facility trauma designation were significantly associated with likelihood of performing TSL. Conclusion: Orthopaedic traumatology and foot and ankle surgeons report similar indications, methods, and low perceived propensity to use TSL in the management of foot and ankle trauma. We found that graduates of 1 fellowship training site were more likely to perform TSL in the setting of acute trauma potentially indicating the need for better scientific data to support this practice. Level of Evidence: Level V, therapeutic.

Talus Fractures: An Update on Current Concepts in Surgical Management.

Talus fractures can be challenging injuries to treat because of complex talar shape, an abundance of articular cartilage, a potentially unforgiving soft-tissue envelope, and an easily injured blood supply. In addition, the spectra of energy involved, soft-tissue injury, and the fracture pattern are wide. Temporizing treatment is sometimes required, including débridement of open fractures, reduction of dislocations, and occasionally spanning external fixation. Definitive treatment first requires an understanding of the fracture pattern, including location and fracture line orientation. Multiple options for surgical exposure exist and are selected based on the fracture pattern and condition of the soft tissues. Newer fixation techniques, including the use of fixed-angle and minifragment implants, are useful in achieving stable fixation.

Musculoskeletal Educational Resources for the Aspiring Orthopaedic Surgeon.

Musculoskeletal (MSK) education is underemphasized in medical school curricula, which can lead to decreased confidence in treating MSK conditions and suboptimal performance on orthopaedic surgery elective rotations or subinternships. Given the low amount of formalized education in MSK medicine, students aiming to learn about orthopaedic surgery must gain much of their foundational knowledge from other resources. However, there are currently no centralized introductory educational resources to fill this need. We provide a framework for navigating the different types of resources available for trainees and highlight the unaddressed needs in this area.