Total Humeral Endoprosthetic Reconstruction: A Systematic Review.

BACKGROUND: Total humeral endoprosthetic reconstruction (THER) is a rare reconstruction option for limb salvage surgery for large humeral neoplasms or bone destruction. MATERIALS AND METHODS: Because of the limited data and need for this procedure, we reviewed the literature surrounding THER and assessed functionality, complications, and revisions using the PubMed, Embase, Ovid, and Scopus databases. RESULTS: Among 29 articles and 175 patients, the most common indication was neoplasm (n=25, 86%), mean follow-up was 61.98 months (SD=55.25 months), and mean Musculoskeletal Tumor Society score was 73.64% (SD=10.69%). Reported complications included 26 (23%) revisions in 7 studies, 35 (36%) cases of shoulder instability in 7 studies, and 13 (13.54%) cases of deep infection in 4 studies. CONCLUSION: THER should be considered with a thorough knowledge of outcomes and potential complications to guide patient and clinician expectations. [Orthopedics. 2024;47(3):e106-e113.].

Enormous myxoid/round cell liposarcoma: A case report.

Myxoid/round cell liposarcomas (MRCLPS) are a rare soft tissue sarcoma. We report the largest sarcoma in our institutional history. We discuss the patient's surgical management and treatment of the tumor and challenges given its dimensions. Several complications arose following primary resection that were managed by a multidisciplinary team. Although MRCLPS can vary in size, large MRCLPS must be treated cautiously given the potential for complications. Additionally, multidisciplinary treatment of MRCLPS is essential in diagnosing and treating these complex cases.

Bilateral Knee Arthrodesis and Total Hip Arthroplasty for Knee and Hip Dysplasia Secondary to Spina Bifida: A Case Report.

Introduction: Spina bifida is a rare neurological condition that, if uncorrected, may cause chronic valgus knee stress difficulty with independent ambulation and significant pain. Current literature lacks comprehensive guidance on surgically correcting progressive hip and knee deformities in spina bifida patients, which include osteotomy and primary. When these options are contraindicated, alternative approaches such as arthrodesis may be indicated, although they remain understudied in this population. Case Report: A 47-year-old man presented with bilateral hip and knee pain. Radiographs demonstrated valgus knee deformities with severe arthrosis and bilateral femoral head subluxation. The patient had a history of spina bifida with chronic lower extremity weakness and neurogenic bladder. He underwent staged bilateral instrumented knee arthrodesis and staged bilateral total hip arthroplasty (THA). Conclusion: This is the first reported case of bilateral instrumented knee arthrodesis in a patient with spina bifida. Orthopedic care of these patients is complex. Surgical correction of symptomatic knee and hip deformities through instrumented arthrodesis and THA may permit an improved functional outcome.

Development and external validation of a machine learning model for prediction of survival in extremity leiomyosarcoma.

PURPOSE: Machine learning (ML) models have been used to predict cancer survival in several sarcoma subtypes. However, none have investigated extremity leiomyosarcoma (LMS). ML is a powerful tool that has the potential to better prognosticate extremity LMS. METHODS: The Surveillance, Epidemiology, and End Results (SEER) database was queried for cases of histologic extremity LMS (n = 634). Patient, tumor, and treatment characteristics were recorded, and ML models were developed to predict 1-, 3-, and 5-year survival. The best performing ML model was externally validated using an institutional cohort of extremity LMS patients (n = 46). RESULTS: All ML models performed best at the 1-year time point and worst at the 5-year time point. On internal validation within the SEER cohort, the best models had c-statistics of 0.75-0.76 at the 5-year time point. The Random Forest (RF) model was the best performing model and used for external validation. This model also performed best at 1-year and worst at 5-year on external validation with c-statistics of 0.90 and 0.87, respectively. The RF model was well calibrated on external validation. This model has been made publicly available at https://rachar.shinyapps.io/lms_app/ CONCLUSIONS: ML models had excellent performance for survival prediction of extremity LMS. Future studies incorporating a larger institutional cohort may be needed to further validate the ML model for LMS prognostication.

Prevalence of Keratoconus Based on Scheimpflug Corneal Tomography Metrics in a Pediatric Population From a Chicago-Based School Age Vision Clinic.

PURPOSE: Determine the pediatric prevalence of keratoconus (KC) using Scheimpflug corneal tomography. METHODS: A prospective observational study was done on subjects aged 3 to 18 years at the Princeton Vision Clinic, Chicago, IL. Scheimpflug tomography (Pentacam HR, OCULUS Optikgerate GmbH) scans (Belin/Ambrósio Enhanced Ectasia BAD3) yielded BAD Final D (Final D) and Back Elevation at the Thinnest Point (BETP) measurements. Criteria differentiating non-KC from KC suspects & KC were, Non-KC -Final D <2.00 in both eyes; KC suspect -Final D ≥2.00 and <3.00 in combination with BETP ≥18 µm for myopia and ≥28 µm for hyperopia/mixed astigmatism in at least one eye; and KC -Final D of ≥3.00 with BETP ≥18 µm for myopia or ≥28 µm for hyperopia/mixed astigmatism in at least one eye. Two thousand two hundred and six subjects were recorded, removing duplicate and poor-quality scans leaving 2007 subjects. RESULTS: Of 2007 subjects, six were classified as KC -prevalence of 1:334, three subjects were KC suspects -prevalence of 1:669, and total prevalence of KC suspects and KC was 1:223. CONCLUSION: The prevalence of KC in children is higher than previously reported, emphasizing the importance of sensitive screening for KC at its earliest manifestation as standard in pediatric comprehensive eye examinations.

Presumed Melanocytoma-Associated Choroidal Neovascular Membrane with Hemorrhage Successfully Treated with Intravitreal Aflibercept Injections.

A patient presented with melanocytoma and associated choroidal neovascular membrane with hemorrhage involving the macula. The patient was treated with monthly aflibercept (Eylea) injections with significant improvement of best corrected visual acuity. In this report, we explore the development of a choroidal neovascular membrane (CNVM) formation in a patient with melanocytoma and the effect of intravitreal aflibercept (Eylea) on disease course. Case report study used patient data obtained from examination and imaging. The patient was treated with monthly intravitreal aflibercept injections leading to complete resolution of CNVM and hemorrhage, with significant improvement of best corrected visual acuity. Awareness and proper monitoring for the sequelae of melanocytoma are important for early detection and prevention of visually threatening outcomes. In cases of melanocytoma-associated CNVM formation with large subretinal hemorrhage, intravitreal aflibercept can be an effective tool for inducing CNVM regression and allowing improvement of visual acuity.

Dislocated Extensor Mechanism in a Child With Bilateral Absent Patella Without Other Congenital Abnormalities.

CASE: A 10-year-old boy presented with bilateral absent patella and dislocation of the extensor mechanism in the left lower extremity. He underwent a lateral release and medial plication of the extensor mechanism with a Roux-Goldthwait procedure, followed by casting and bracing treatment. The patient fully recovered with a return to sports and improved active range of motion. CONCLUSION: Bilateral absent patella without other congenital anomalies is an exceedingly rare condition and can be accompanied by a dislocation of the extensor mechanism. Treatment should address functional limitations, including extensor mechanism dislocation, when present.

Less Complex Contact Lens Required for a Patient With Keratoconus After Topography-Guided Photorefractive Keratectomy.

ABSTRACT: In this report, we discuss contact lens (CL) fitting in a patient with a history of keratoconus (KC), before and after undergoing topography-guided photorefractive keratectomy (TG PRK). Before TG PRK, the patient failed multiple CL modalities and reported difficulty with his habitual CLs and inadequate spectacle-corrected visual acuity to perform his activities of daily living. In this case, a collaborative, comprehensive approach to visual management in a patient with KC was used, and after TG PRK was performed to improve his corneal contour and symmetry, our patient was fit with a standard soft CL and additionally had improved spectacle-corrected visual acuity.

Long-Term Outcomes After Corneal Cross-linking for Progressive Keratoconus and Corneal Ectasia: A 10-Year Follow-Up of the Pivotal Study.

OBJECTIVES: To report on the topographic and visual outcomes 10 years after corneal cross-linking in patients with progressive keratoconus and corneal ectasia after refractive surgery. METHODS: Cross-sectional cohort study of an original, prospective, randomized, clinical trial. Patients treated in a single center cornea and refractive surgery practice as part of the U.S. pivotal trials, which led to the Food and Drug Administration approval of corneal cross-linking, were recruited for a 10-year follow-up examination. LogMar lines (LL) of uncorrected visual acuity (UCVA) and best spectacle--corrected visual acuity (BSCVA), maximum keratometry, and thinnest pachymetry were evaluated. In addition, the Belin ABCD progression display was used to determine progression (95% confidence interval) of the anterior curvature, posterior curvature, and corneal thickness of each individual eye included. RESULTS: Nineteen eyes of 13 patients treated with standard cross-linking returned for a 10-year follow-up examination. Mean maximum keratometry changed from 58.2±12.0 diopters (D) to 58.3±10.1 D, thinnest pachymetry changed from 440.6±51.6 µm to 442.3±54.4 µm, UCVA changed from 0.79±0.42 LL to 0.86±0.46 LL, and BSCVA changed from 0.38±0.26 LL to 0.33±0.34 LL, 10 years after cross-linking. Individually, 68.5% of the entire cohort, 81.8% of keratoconus eyes, and 50% of eyes with corneal ectasia remained topographically stable 10 years after standard cross-linking. CONCLUSIONS: In the entire cohort, visual acuity and topography remained stable 10 years after cross-linking. Over the long-term, eyes with keratoconus seem to be more stable than those with corneal ectasia.

Correlation of Manifest Refraction and Simulated Keratometry to Tomography Characteristics in Patients With Keratoconus.

OBJECTIVES: To report on baseline refractive and keratometric values and their correlation with tomographic characteristics of eyes with keratoconus (KC). METHODS: Retrospective chart review of patients treated in a single-center cornea and refractive surgery practice. Baseline topographic measurements were reviewed for 1,012 keratoconic eyes of 586 patients between 2008 and 2018. The manifest refraction, thinnest pachymetry (P thin ), corneal astigmatism (K astig ), and the maximum (K max ), steep (K steep ), flat (K flat ), and mean (K mean ) keratometry were analyzed. The location of K max (x, y) was used to determine central (<1 mm), paracentral (1-3 mm), pericentral (3-5 mm), or peripheral (>5 mm) cone locations. RESULTS: In the entire cohort, the mean manifest sphere was -2.2±4.4 diopters (D) and the cylinder was -3.2±2.3 D. In total, 48.6% of patients had against the rule (ATR) manifest astigmatism (M astig ). The average K astig was 3.8±2.7 D, and unlike the manifest axis, 50.2% of patients had with the rule (WTR) K astig . Patients with a K max less than 50 D had an M astig of -1.9±1.6 D, 45.9% of which was ATR M astig . With respect to baseline tomography measurements, K max , K steep , K flat , and K mean were 58.0±9.4, 50.6±6.5, 46.8±5.9, and 48.6±6.1 D, respectively. There was a weak correlation between K max and simulated keratometry (K steep , K flat , and K mean ) for patients with a K max less than 60 D. CONCLUSIONS: Simulated keratometry is poorly correlated with KC severity until the disease is more severe. M astig ≥2 D and ATR M astig were correlated with KC at all levels of severity. M astig ≥2 D and ATR M astig may serve as a simple, inexpensive, and widely available indicator for topographic analysis to identify possible KC and suggest further workup; however, further prospective studies are needed to confirm its utility.

Corneal tissue addition keratoplasty: new intrastromal inlay procedure for keratoconus using femtosecond laser-shaped preserved corneal tissue.

PURPOSE: To report results of Corneal Tissue Addition Keratoplasty (CTAK) for keratoconus (KC) and ectasia after laser in situ keratomileusis. SETTING: Cornea and refractive surgery practice. DESIGN: Single center, prospective, open label clinical trial. METHODS: 21 eyes of 18 patients underwent CTAK. A tissue inlay of preserved corneal tissue was cut to customized specifications with a femtosecond laser and placed in a laser-created channel in the host cornea. Postoperative uncorrected and corrected distance visual acuity (UDVA, CDVA), manifest refraction spherical equivalent (MRSE), topographic mean keratometry (Kmean), maximum keratometry (Kmax), and the point of maximum flattening (Kmaxflat) were measured. RESULTS: Average UDVA improved from 1.21 ± 0.35 logMAR lines (LL) (20/327) to 0.61 ± 0.25 LL (20/82) ( P < .001). Average CDVA improved from 0.62 ± 0.33 LL (20/82) to 0.34 ± 0.21 LL (20/43) ( P = .002), and average MRSE improved from -6.25 ± 5.45 diopters (D) to -1.61 ± 3.33 D ( P = .002). Individually, 20 eyes (95.2%) gained more than 2 lines of UDVA, with 10 eyes (47.6%) gaining more than 6 lines, and no eyes worsening. 12 eyes (57.1%) gained at least 2 lines of CDVA, with 1 eye worsening by more than 2 lines. At 6 months, average Kmean flattened by -8.44 D ( P = .002), Kmax flattened by -6.91 D ( P = .096), and mean Kmaxflat was -16.03 D. CONCLUSIONS: CTAK is a promising procedure to improve visual acuity and topography in patients with KC and ectasia.

Local Trends in Total Joint Arthroplasty and Orthopaedic Surgeon Distribution in the United States.

INTRODUCTION: Total joint arthroplasty (TJA) volume and the number of orthopaedic surgeons in the United States have increased in recent years, but local growth variation has not been studied. This study assesses recent changes in state-level distribution of orthopaedic surgeons in the United States and corresponding local trends in TJA volume. METHODS: Data from the National Inpatient Sample database (2000 to 2014) were reviewed. Urban versus rural setting and teaching versus nonteaching hospitals were identified among TJA procedures for comparison. Data from the American Academy of Orthopaedic Surgeons (2002 to 2016) detailing orthopaedic surgeon practice location were evaluated, and linear regression analysis was used to correlate state population data with orthopaedic surgeon density. RESULTS: From 2000 to 2014, there was a 0.1% to 0.3% (P < 0.01) annual decrease in the proportion of TJA procedures conducted in rural hospitals. No notable change was observed in the proportion of TJA procedures conducted at urban teaching versus nonteaching hospitals. Linear regression analysis demonstrated that decreased state population was associated with higher orthopaedic surgeon density (adjusted R2 = 0.114, P < 0.01). States with a higher percentage of population living in rural areas had a lower density of orthopaedic surgeons in the South region and a higher density of orthopaedic surgeons in the remainder of the county. CONCLUSIONS: Less populated, rural states have a higher density of orthopaedic surgeons than states with increased population and less rural areas. Although TJA volume has increased since 2000, the proportion of TJA procedures conducted at rural hospitals has decreased. No change was found in the proportion of TJA procedures conducted at urban teaching versus nonteaching hospitals. This may indicate that more patients living in rural areas are seeking TJA care in urban centers. Future studies are needed to confirm this and ensure that patients living in rural areas have appropriate access to TJA care.

Short term outcomes of an enhanced recovery after surgery (ERAS) pathway versus a traditional discharge pathway after posterior spinal fusion for adolescent idiopathic scoliosis.

PURPOSE: Enhanced Recovery after Surgery (ERAS) pathways have been shown to decrease length of stay (LOS) after posterior spinal fusion (PSF) for adolescent idiopathic scoliosis (AIS). The aim of this study was to compare immediate post-operative outcomes following an ERAS pathway with a traditional pathway for AIS. METHODS: A prospective dual-center study of patients treated using an ERAS pathway (203 patients) or a traditional discharge (TD) pathway (73 patients) was performed with focus on pain at discharge, quality of life at one month, and return to school/work. RESULTS: LOS was 55% less in the ERAS group (4.8 days TD vs. 2.2 days ERAS, p < 0.001). Length of surgery (4.8 h TD vs. 2.8 h, p < 0.001) and EBL (500 cc vs. 240 cc, p < 0.001) were greater in the TD group, likely related to larger curve magnitudes ((62.0° TD vs. 54.0° ERAS, p < 0.001), a higher percentage of patients undergoing osteotomies (94% vs. 46%, p < 0.001) and more levels fused (11.4 ± 1.6 vs. 10.1 ± 2.6, p < 0.001) in the TD group. Regression analysis showed no difference in Visual Analog Score (VAS) score at discharge or quality of recovery using the QOR9 instrument between groups at follow up. There was no difference in return to school (p = 0.43) and parents' return to work (p = 0.61) between the groups. CONCLUSION: Patients managed with an ERAS pathway had similar pain scores at discharge than those managed with a TD pathway. Both groups showed evidence of rapid return to normalcy by the first follow up visit.

Despite Equivalent Medicare Reimbursement, Facility Costs for Outpatient Total Knee Arthroplasty Are Higher Than Unicompartmental Knee Arthroplasty.

BACKGROUND: With the recent removal of total knee arthroplasty (TKA) from the Centers for Medicare and Medicaid Services (CMS) Inpatient Only list, facility reimbursement for outpatient TKA now falls under the Outpatient Prospective Payment System at the same rate as unicompartmental knee arthroplasty (UKA). The purpose of this study was to compare true facility costs of patients undergoing outpatient TKA with those undergoing UKA. METHODS: We reviewed a consecutive series of 2310 outpatient TKA and 231 UKA patients from 2018 to 2019. Outpatient status was defined as a hospital stay of less than 2 midnights. Facility costs were calculated using a time-driven, activity-based costing algorithm. Implants, supplies, medications, and personnel costs were compared between outpatient TKA and UKA patients. A multivariate analysis was performed to control for confounding medical and demographic variables. RESULTS: When compared with patients undergoing UKA, outpatient TKA patients had higher implant costs ($3403 vs $3081; P < .001) and overall hospital costs ($6350 vs $5594; P < .001). Outpatient TKA patients had a greater length of stay (1.2 vs 0.5 days; P < .001) and greater postoperative personnel costs ($783 vs $166; P < .001) than UKA patients. When controlling for comorbidities, outpatient TKA was associated with a $803 (P < .001) increase in overall facility costs compared with UKA. CONCLUSION: Despite equivalent reimbursement from CMS as UKA, outpatient TKA has increased facility costs to the hospital. Although implant costs can vary greatly by institution, CMS should consider appropriately reimbursing outpatient TKA for the additional personnel costs when compared with UKA.

In Kinematically Aligned Total Knee Arthroplasty, Failure to Recreate Native Tibial Alignment Is Associated With Early Revision.

BACKGROUND: The goal of kinematically aligned (KA) total knee arthroplasty (TKA) is to restore native knee anatomy. However, there are concerns about patellofemoral tracking problems with this technique that lead to early revision. We measured the differences between preoperative anatomic alignment and postoperative component alignment in a consecutive series of KA TKA and evaluated the association between alignment changes and the likelihood of early revision. METHODS: The charts of 219 patients who underwent 275 KA TKA procedures were reviewed. Preoperative anatomic alignment and postoperative tibial and femoral component alignment were measured radiographically. The difference in component alignment compared with preoperative anatomic alignment was compared between patients who underwent aseptic revision and those who did not at a minimum of 12 months of follow-up. Receiver operating characteristic curves were created for statistically significant variables, and the Youden index was used to determine optimal alignment thresholds with regard to likelihood of revision surgery. RESULTS: Change in tibial component alignment compared with native alignment was greater (P = .005) in the revision group (5.0° ± 3.7° of increased varus compared with preoperative anatomic tibial angle) than in the nonrevision group (1.3° ± 4.2° of increased varus). The Youden index indicated that increasing tibial varus by >2.2° or more is associated with increased likelihood of revision. Preoperative anatomic alignment and change in femoral alignment and overall joint alignment (ie, Q angle) were not associated with increased likelihood of revision. CONCLUSION: Small increases in tibial component varus compared with native alignment are associated with early aseptic revision in patients undergoing KA TKA.

Protein rethreading: A novel approach to protein design.

Protein engineering is an important tool for the design of proteins with novel and desirable features. Templates from the protein databank (PDB) are often used as initial models that can be modified to introduce new properties. We examine whether it is possible to reconnect a protein in a manner that generates a new topology yet preserves its structural integrity. Here, we describe the rethreading of dihydrofolate reductase (DHFR) from E. coli (wtDHFR). The rethreading process involved the removal of three native loops, and the introduction of three new loops with alternate connections. The structure of the rethreaded DHFR (rDHFR-1) was determined to 1.6 Å, demonstrating the success of the rethreading process. Both wtDHFR and rDHFR-1 exhibited similar affinities towards methotrexate. However, rDHFR-1 showed no reducing activity towards dihydrofolate, and exhibited about ~6-fold lower affinity towards NADPH than wtDHFR. This work demonstrates that protein rethreading can be a powerful tool for the design of a large array of proteins with novel structures and topologies, and that by careful rearrangement of a protein sequence, the sequence to structure relationship can be expanded substantially.

Auto-validation of fluorescent primer extension genotyping assay using signal clustering and neural networks.

BACKGROUND: SNP genotyping typically incorporates a review step to ensure that the genotype calls for a particular SNP are correct. For high-throughput genotyping, such as that provided by the GenomeLab SNPstream instrument from Beckman Coulter, Inc., the manual review used for low-volume genotyping becomes a major bottleneck. The work reported here describes the application of a neural network to automate the review of results. RESULTS: We describe an approach to reviewing the quality of primer extension 2-color fluorescent reactions by clustering optical signals obtained from multiple samples and a single reaction set-up. The method evaluates the quality of the signal clusters from the genotyping results. We developed 64 scores to measure the geometry and position of the signal clusters. The expected signal distribution was represented by a distribution of a 64-component parametric vector obtained by training the two-layer neural network onto a set of 10,968 manually reviewed 2D plots containing the signal clusters. CONCLUSION: The neural network approach described in this paper may be used with results from the GenomeLab SNPstream instrument for high-throughput SNP genotyping. The overall correlation with manual revision was 0.844. The approach can be applied to a quality review of results from other high-throughput fluorescent-based biochemical assays in a high-throughput mode.