Custom Patient-Specific 3D-Printed Titanium Truss Tibiotalocalcaneal Arthrodesis Implants for Failed Total Ankle Replacements: Classification, Technical Tips, and Treatment Algorithm.

BACKGROUND: The management of failed total ankle replacements, with significant loss of bone stock, is challenging with high rates of complications and associated morbidity. Recent technological advances have enabled the development of patient-customized 3D-printed titanium truss arthrodesis implants, which offer an alternative salvage option for failed total ankle replacements. METHODS: A prospective observational study was performed of 6 cases of failed total ankle replacements that were managed using custom patient-specific 3D-printed titanium truss arthrodesis implants. Technical tips, classification, and a treatment algorithm were developed based on our initial experience. RESULTS: Between November 2018 and March 2022, 6 patients underwent arthrodesis for failed total ankle replacements. Follow-up was available for all cases. The mean follow-up was 3.0 years (range 1-4.5). The mean MOXFQ Index improved from 73.1 to 32.3 (P < .05). The mean EQ-5D-5L Index improved from 0.366 to 0.743 (P < .05) and the EQ-VAS also improved from 53.0 to 63.3 (P = .36). The mean VAS-Pain score at final follow-up was 27.5. There were no cases of nonunion. None of the patients were smokers. The overall complication rate was 50%. Two patients returned to surgery: one for wound washout following TAR explantation and a second for removal of metalwork 2 years following surgery for a prosthetic joint infection secondary to hematogenous spread. No patients underwent revision fixation or amputation. CONCLUSION: Custom patient-specific 3D-printed titanium truss arthrodesis implants are a viable treatment option for failed total ankle replacements.

Analysis of COVID-19 Case Demographics and Disease Outcomes in Gary, Indiana.

BACKGROUND: The COVID-19 pandemic further exposed the prevalence of existing health disparities in Black communities in the U.S. The current study evaluates COVID-19 data collected in Gary, Indiana, from June 2020 to June 2021. We hypothesized that the number of COVID-19 cases, hospitalizations, and deaths were influenced by race and income. METHODS: In collaboration with the Gary Health Department (GHD), we analyzed demographic data on COVID-19-positive cases. RESULTS: Compared to Gary's non-Black population, age- and population-adjusted rates of hospitalizations and deaths in the Black population were 3-fold (p < 0.0001) and 2-fold (p < 0.05) higher, respectively. This is despite a higher infection rate (p < 0.0001) in the non-Black population. The median household income of a zip code was negatively correlated with COVID-19 hospitalizations (R2 = 0.6345, p = 0.03), but did not correlate with infections and deaths. CONCLUSIONS: The current study demonstrates clear health disparities of income and race in the context of COVID-19-related infections and outcomes in the city of Gary. Indiana University School of Medicine Northwest and GHD officials can collaborate to utilize these data for the reallocation of resources and health education efforts in Gary's highly populated, low-income, and predominantly Black neighborhoods. It should also prompt further investigation into national health resource allocation.

Increased Longevity and Pumping Performance of an Injection Molded Soft Total Artificial Heart.

In this work, we present an injection molded soft total artificial heart (sTAH) produced from high-temperature vulcanizing silicone using an industrial metal injection mold. At 60 beats per minute, the sTAH exhibited a total cardiac output of over 16 L/min against physiological pressures on a mock circulation and was pumped continuously for 110,000 actuation cycles. Finite element analysis was used to identify stress concentrations within the sTAH, allowing an optimized design to be proposed.

Making Things Easier: A Simple Novel Method to Fix a Dorsiflexion Osteotomy of the First Metatarsal.

A first ray dorsiflexion osteotomy is commonly performed for cavovarus foot correction. There are multiple techniques to fix this osteotomy, ranging from wires, screws, and plates or a combination of these. We present our results using a varisation staple (Biomet©) as an alternative fixation device. We performed a retrospective outcome analysis of a consecutive series of 10 cavovarus feet that underwent a dorsiflexion osteotomy (dorsal closing wedge) of the first metatarsal fixed with two varisation staples. The results were measured at a mean three monthly follow-ups and included union and complication rates, as well as clinical and radiographic assessment of cavus deformity correction. There was a 100% union rate with no complications or cases of delayed union. No metalwork removal was requested in any case at follow-up. First ray dorsiflexion osteotomies are most commonly fixed using a 3.5mm cortical screw. We demonstrate that our alternative and novel technique using varisation staples achieved a 100% union rate while avoiding the prominent hardware complications known to occur with cortical screws or plates.

Fractures of the anterior process of the calcaneum; a review and proposed treatment algorithm.

BACKGROUND: There remains a lack of recognition of these fractures, which leads to a delay in diagnosis and appropriate management. METHODS: A comprehensive literature search was performed. Following inclusion and exclusion criteria, 23 studies were available for analysis. RESULTS: Delay in diagnosis is common and has a negative impact on outcome. If an APC fracture is suspected; anteroposterior, lateral and oblique plain radiographs should be requested. Further investigation with computed tomography or magnetic resonance imaging is indicated if plain radiographs are inconclusive and patient remains symptomatic. Non-operative measures are usually adequate for most undisplaced fractures, however surgical intervention maybe required for large, intra-articular fractures in the acute setting and for non-union. CONCLUSIONS: A treatment algorithm is suggested that may help with the diagnosis and management of these injuries. LEVEL OF EVIDENCE: Level IV.

Delayed Allergic Reaction to ChloraPrepTM in Foot and Ankle Surgery.

Chlorhexidine-based skin preparations are frequently used in orthopaedic surgery. We report 2 recent cases of patients suffering significant allergic reactions to ChloraPrepTM complicating routine foot and ankle surgery. We advise vigilance for this possible issue and recommend thorough removal of all preparation at the end of the procedure.

Long-Term Performance of a Pneumatically Actuated Soft Pump Manufactured by Rubber Compression Molding.

We present a long-term performance study on a pneumatically actuated soft pump (SP). The pump was manufactured by adapting rubber compression technology. Important parameters influencing pump performance (e.g., inflation and deflation times and fluid outlet pressures) were studied. Based on design improvement and material selection, SP durability could be enhanced for over 1 million actuation cycles. This resulted in conveyance of more than 140,000 L of water in less than 12 days. In a next step, we analyzed our SP on a hybrid mock circulation and achieved 1.8 L/min against 10 kPa (75 mmHg). In situ analysis by color Doppler imaging further allowed real-time assessment of the SP's diaphragm motion. We then summarized our findings for future SP development with particular use as a heart replacement therapy. This work demonstrates a new manufacturing approach for future development of long-term stable SPs.

Management of Paget's Disease of the Calcaneum.

The calcaneum is not the most common site for Paget's disease of bone, with only a few reports of monostotic involvement. We present 2 cases of Paget's disease of bone affecting the calcaneus, present an overview of the published data, and describe our management of these interesting cases.

Correlation and comparison of syndesmosis dimension on CT and MRI.

INTRODUCTION: Various methods using CT scan have been described to diagnose distal tibiofibular syndesmotic injuries. However, CT scan does not take into account the amount of cartilage within the distal tibiofibular joint and could therefore lead to false positive results. We present the first study correlating the findings of the distal tibiofibular syndesmosis on CT and MRI scans. METHODS: CT and MRI scan of consecutive patients over a period of 18 months, and of a time lapsed less than 12 months between the two imaging modalities, were reviewed. Measurements of the distal tibiofibular syndesmosis were taken according to a previously published study at the level of the distal tibial physeal scar. RESULTS: Twenty-six ankles from 25 patients were included in this study for analysis. Significant difference between CT and MRI assessments in the overall distal tibiofibular dimensions and in the posterior distal tibiofibular distance for those ankles with evidence of osteoarthritis was found. Interclass correlation coefficients suggest that such methodology was reproducible and reliable. CONCLUSION: When the widening found on a CT scan is minor or the diagnosis is equivocal, a contralateral comparative CT or an ipsilateral MRI scan is recommended to prevent misdiagnosis. LEVEL OF EVIDENCE: Level IV.

Functional outcomes of total hip arthroplasty in patients aged 30 years or less: a systematic review and meta-analysis.

INTRODUCTION: Young adult hip surgery is a growing subspecialty. Increasingly total hip arthroplasty (THA) is offered to patients aged 30 or less suffering from end-stage hip arthropathy from a variety of congenital, developmental and acquired conditions. There is a paucity of evidence to advise such patients and surgeons alike on the functional outcomes of THA in this age group, as individual studies tend to include small cohorts. METHODS: A systematic review and meta-analysis was performed to assess whether THA in patients aged 30 years or less provides significant functional improvement. The primary outcome measure was change in Harris Hip Score. Secondary outcome measures were implant survivorship and the effect of fixation type and bearing surface. RESULTS: The results of 743 primary THA procedures were included. Weighted mean patient age was 22.7 years. Harris Hip Score improved by a weighted mean difference of 42.17 points out of 100 (95% confidence interval, 36.48-47.86 points, p<0.001) after THA at a weighted mean follow-up of 8.4 years. Pooled revision rate was 5.0% for the same time period. CONCLUSIONS: This is the largest review to date of THA in patients aged 30 or less. The results show significant functional improvement measured by Harris Hip Score. The revision rate of 5% at 8.4 years is comparable to the general THA population. This contrasts high revision rates reported in older reviews of the literature, suggesting adoption of improved techniques and implants in the more recent literature.

A Simple Alternative Treatment for Syndactyly of the Toe.

Toe syndactyly is a common congenital malformation affecting approximately 1 in 2000 people and can cause significant emotional and psychological distress for the patient. We report a case of a 41-year-old female who was concerned about the aesthetic appearance of her bilateral second and third toe with incomplete, simple syndactyly and had requested surgical correction. A number of operative techniques have been described in the orthopedic and plastic surgery data, with no one technique proving superior. We used medical tattooing to create the appearance of a complete interdigital cleft. This low-risk, and low-cost procedure resulted in a satisfactory outcome for the patient. To the best of our knowledge, this is the first reported case using this technique, which we propose as a simple alternative to surgical correction of toe syndactyly.

Holographic investigations of azobenzene-containing low-molecular-weight compounds in pure materials and binary blends with polystyrene.

This paper reports on the synthesis and the thermal and optical properties of photochromic low-molecular-weight compounds, especially with respect to the formation of holographic volume gratings in the pure materials and in binary blends with polystyrene. Its aim is to provide a basic understanding of the holographic response with regard to the molecular structure, and thus to show a way to obtain suitable rewritable materials with high sensitivity for holographic data storage. The photoactive low-molecular-weight compounds consist of a central core with three or four azobenzene-based arms attached through esterification. Four different cores were investigated that influence the glass transition temperature and the glass-forming properties. Additional structural variations were introduced by the polar terminal substituent at the azobenzene chromophore to fine-tune the optical properties and the holographic response. Films of the neat compounds were investigated in holographic experiments, especially with regard to the material sensitivity. In binary blends of the low-molecular-weight compounds with polystyrene, the influence of a polymer matrix on the behavior in holographic experiments was studied. The most promising material combination was also investigated at elevated temperatures, at which the holographic recording sensitivity is even higher.

Polarization dependence of the formation of surface relief gratings in azobenzene-containing molecular glasses.

This paper presents a comprehensive study of the formation of surface relief gratings in a series of photoresponsive molecular glasses. Holographic experiments were performed on films of the azobenzene-containing molecular glasses. Seven relevant polarization configurations of the writing beams were systematically applied, and simultaneously the diffraction efficiency was monitored during the process of inscription. The temporal evolution of the diffraction efficiency can be precisely simulated with a model which takes both the surface relief and the phase grating in the volume into account. From the measured diffraction efficiencies, the modulation heights can be directly calculated and they were independently confirmed by atomic force microscopy. We found that all experimental results can be explained with the gradient force model, and we suggest that the grating heights generated with different writing polarizations can be ascribed to the varying strengths of the gradient force. For materials with different substituents at the azobenzene chromophore, the optical susceptibility at the writing laser wavelength and, therefore, the gradient force varies. By applying the most efficient polarization configuration in combination with the best material, we were able to reach modulation heights of up to 600 nm, which is a factor of 2 higher than modulations usually reported for azobenzene-containing polymers.

Morbidity and determinants of health on youth expeditions.

OBJECTIVE: To document the prevalence of illness and injury on youth expeditions and analyze specific determinants of health. METHODS: Two thousand nine hundred fifteen people, aged 15 to 18 years, traveled with a commercial company, World Challenge Expeditions Ltd, between June and September 2001. Adult team leaders were required to keep medical cards for each person. This study is a retrospective analysis of these medical cards. RESULTS: Completed medical cards were available for 2402 people (82%). There were no medical problems in 36% of people. Illness or injury was reported by 64% (mean, 2.0 medical problems per person). Of the medical problems, 6% were defined as serious, and 1% were admitted to the hospital. One fatality occurred. The five most prevalent medical problems were diarrhea (22%), nausea and vomiting (20%), cold or sore throat (11%), headache (11%), and trauma (10%). Girls reported 19% more medical problems than the boys reported. Gastrointestinal illness was significantly increased at high altitude. Illness and injury were most prevalent in South America and least prevalent in Australasia. CONCLUSIONS: Our results demonstrate that in young people traveling to remote parts of the world, illness and injury are common. Serious incidents are rare; however, the death of one person does highlight the dangers present. This study may help risk assessment for young people considering taking part in an expedition.