Navigated functional alignment total knee arthroplasty achieves reliable, reproducible and accurate results with high patient satisfaction.

PURPOSE: The decision on which technique to perform a total knee arthroplasty (TKA) has become more complicated over the last decade. Perceived limitations of mechanical alignment (MA) and kinematic alignment (KA) have led to the development of the functional alignment (FA) philosophy. This study aims to report the 2-year results of an initial patient cohort in terms of revision rate, PROMs and complications for Computer Aided Surgery (CAS) Navigated FA TKA. METHODS: This paper reports a single surgeon's outcomes of 165 consecutive CAS FA TKAs. The final follow-up was 24 months. Pre-operative and post-operative patient-reported outcome measures, WOMAC and KSS, and intra-operative CAS data, including alignment, kinematic curves, and gaps, are reported. Stress kinematic curves were analysed for correlation with CAS final alignment and CAS final alignment with radiographic long-leg alignment. Pre- and post-operative CPAK and knee phenotypes were recorded. Three different types of prostheses from two manufacturers were used, and outcomes were compared. Soft tissue releases, revision and complication data are also reported. RESULTS: Mean pre-operative WOMAC was 48.8 and 1.2 at the time of the final follow-up. KSS was 48.8 and 93.7, respectively. Pre- and post-operative range of motion was 118.6° and 120.1°, respectively. Pre-operative and final kinematic curve prediction had an accuracy of 91.8%. CAS data pre-operative stress alignment and final alignment strongly correlate in extension and flexion, r = 0.926 and 0.856, p < 0.001. No statistical outcome difference was detected between the types of prostheses. 14.5% of patients required soft tissue release, with the lateral release (50%) and posterior capsule (29%) being the most common. CONCLUSION: CAS FA TKA in this cohort proved to be a predictable, reliable, and reproducible technique with acceptable short-term revision rates and high PROMs. FA can account for extremes in individual patient bony morphology and achieve desired gap and kinematic targets with soft tissue releases required in only 14.5% of patients. LEVEL OF EVIDENCE: IV (retrospective case series review).

Wide variation in tibial slopes and trochlear angles in the arthritic knee: a CT evaluation of 4116 pre-operative knees.

PURPOSE: As surgeons continue to grapple with persistent issues of patient dissatisfaction post-TKA, the literature has focused on the coronal plane when considering alignment strategies but has largely ignored the sagittal and axial planes. The purpose of this retrospective observational cohort study is to evaluate variability in knee anatomy and alignment beyond the coronal plane and rationalise how this relates to existing arthroplasty alignment philosophies. METHODS: 4116 knee CTs from 360 Knee Systems© database of arthritic pre-operative TKA patients were evaluated. Standardised bony landmarks were used in each CT to determine the hip-knee angle, medial proximal tibial angle, lateral distal femoral angle, medial plateau posterior tibial slope, lateral plateau posterior tibial slope, trochlea angle (TA) to distal femoral angle (TA-DFA) and TA to posterior condylar angle (TA-PCA). Analysis was performed to determine the distributions of each measure across the cohort population. RESULTS: Both the medial and lateral PTS ranged from 5° anterior to 25° posterior. 22.6% of patients had differential PTS greater than 5°. 14.5% have greater lateral PTS (mean difference to medial PTS of 4.8° ± 5.0°), whilst 31.0% have greater medial PTS (mean difference to lateral PTS of 5.7° ± 3.2°). 14% of TA-DFAs and 5.2% of TA-PCAs vary greater than 10°. CONCLUSION: This study demonstrates a wide variation in tibial slope, differential slope between the medial and lateral tibial plateau as well as variation in the trochlear geometry. There has been an overemphasis in the literature on coronal alignment, ignoring the considerable variability present in tibial and patellofemoral morphology. Existing arthroplasty techniques are based on assumptions that may not adequately address the anatomy of morphologic outliers and could lead to dissatisfaction. LEVEL OF EVIDENCE: III-retrospective cohort study.

Ankle fracture management using smartphone multimedia messaging service (MMS) imaging - How reliable and to what point?

BACKGROUND: The use of smartphones and multimedia messaging service (MMS) continues to increase in day to day orthopaedic clinical practice. However, there is limited evidence to support the safe utilisation of MMS. OBJECTIVES: The aim of this study was to correlate the performance of MMS imaging to picture archiving and communication systems (PACS) imaging within the setting of diagnosis and management of ankle fractures. METHODS: The ankle fracture radiograph series of 82 consecutive patients were evaluated by five orthopaedic consultant specialists. A questionnaire regarding diagnosis and preferred management was completed separately for each patient using smartphone and PACS images. Statistical analysis was performed using Intraclass Correlation Coefficient (ICC). RESULTS: Ankle fracture diagnosis showed strong to excellent correlation both inter- and intraobserver MMS vs PACS when using the Weber (0.815, 0.988), Anatomical (0.858, 0.988), and AO classification systems (0.855, 0.985). MMS was less reliable than PACS in determining many management options. CONCLUSION: The reliability of ankle fracture classification using MMS image viewing was not significantly different to interpretation on PACS workstations. Smartphone use in ankle fracture classification is supported by this study. Smartphone use was less accurate than PACS in devising management plans and future use should be limited to making only initial plans that must be corroberated with PACS and intraoperative findings prior to definitive fixation.

Brain Natriuretic Peptide levels on hospital admission are a useful predictor of cardiac complications and mortality in geriatric patients with proximal femur fractures.

Purpose: Proximal femur fractures in geriatric patients are associated with increased morbidity and mortality. This study investigates Brain Natriuretic Peptide immunoassay levels taken at the time of hospital admission in predicting cardiac complications and mortality in geriatric patients with a proximal femur fracture. Methods: A single-site prospective cohort study at a large tertiary care, level 1 trauma centre was conducted on all consecutive geriatric patients aged greater than 60 years who sustained a proximal femur fracture. Investigators collected Brain Natriuretic Peptide levels from venous blood samples on admission to the Emergency Department. The main outcome measurements were inpatient cardiovascular complications, and all-cause mortality at 30-day, 90-day, one-year, and nine-years. Results: Over a one-year period, 112 patients were enrolled. The average age was 82.7 years, and the average follow up was 6 years and 6 months (range, 2 days to 9 years). No patients were lost to follow up. There were 44 new or exacerbations of pre-existing cardiac complications requiring management recorded in 30 (26.8%) patients. Mortality at 30 days was 9.8%, 90 days was 16.1%, and one year was 24.1%, with deceased patients having a statistically significant elevated Brain Natriuretic Peptide immunoassay on hospital admission. The Kaplan-Meier graph demonstrated a trend towards increasing Brain Natriuretic Peptide and adverse survivorship risk. The Charlson Comorbidity Index was statistically significant in predicting overall survival probability. Conclusion: Brain Natriuretic Peptide immunoassay on hospital admission may be utilised to identify patients at risk of cardiac complications and mortality to guide further investigations, operative planning, the consent process, and post-operative monitoring.

Three-Dimensional CT-Based Limb Length Evaluation Is Highly Dependent on Anatomical Landmark Selection and Pelvic Asymmetry.

Background: Pelvic skeletal asymmetry can result in rotational differences and morphologic bony prominence variance between the left and right hemipelvis. When selecting bony reference points for modern computed tomography-based robotic total hip arthroplasty planning, it is unclear which bony landmarks are the most reliable and accurate, especially in the presence of significant pelvic asymmetry. Methods: A retrospective study was conducted utilizing a database of computed tomography scans. Multiple bony landmarks in the pelvis and femur were selected for comparison, with the aim of measuring pelvic asymmetry. Specifically, the study measured the average difference in lateral offset between the left and right hemipelvis caused by pelvic asymmetry. Landmarks were also compared to determine the impact of pelvic asymmetry on hip length, femur length, and limb length discrepancies. Furthermore, a scenario was simulated in the software whereby a total hip replacement was inserted, potentially changing the hip length. The impact of pelvic reference point selection on the measurement of this simulated change in hip length was examined. Results: This study population showed widespread pelvic asymmetry. The anatomical landmarks of the opposite side cannot be relied upon for predicting the anatomy of the affected side. The center of rotation axis is more reliable than the inferior obturator foramen axis for hip length discrepancy due to pelvic asymmetry (P < .05). Conclusions: Current computer-assisted surgery THR software reports measurements of global offset and hip length that do not consider pelvic asymmetry. Surgeons are not given confidence ranges to represent the potential impact of asymmetry on the global offset and hip length values. Surgeons following these numbers to guide implant position may incur implant placement error should significant pelvic asymmetry be present in a given patient.

Image-derived instrumentation vs. conventional instrumentation with 3D planning for glenoid component placement in reverse total shoulder replacements: a randomized controlled trial.

Hypothesis: Glenoid baseplate positioning for reverse total shoulder arthroplasty (rTSA) is important for stability and longevity, with techniques such as image-derived instrumentation (IDI) developed for improving implant placement accuracy. We performed a single-blinded randomized controlled trial comparing glenoid baseplate insertion accuracy with 3D preoperative planning and IDI jigs vs. 3D preoperative planning and conventional instrumentation. Methods: All patients had a preoperative 3D computed tomography to create an IDI; then underwent rTSA according to their randomized method. Repeat computed tomography scans performed at six weeks postoperatively were compared to the preoperative plan to assess for accuracy of implantation. Patient-reported outcome measures and plain radiographs were collected with 2-year follow-up. Results: Forty-seven rTSA patients were included (IDI n = 24, conventional instrumentation n = 23). The IDI group was more likely to have a guidewire placement within 2mm of the preoperative plan in the superior/inferior plane (P = .01); and exhibited a smaller degree of error when the native glenoid retroversion was >10° (P = .047). There was no difference in patient-reported outcome measures or other radiographic parameters between the two groups. Conclusion: IDI is an accurate method for glenoid guidewire and component placement in rTSA, particularly in the superior/inferior plane and in glenoids with native retroversion >10°, when compared to conventional instrumentation.

Personalized Cancer Monitoring Assay for the Detection of ctDNA in Patients with Solid Tumors.

BACKGROUND: Highly sensitive molecular assays have been developed to detect plasma-based circulating tumor DNA (ctDNA), and emerging evidence suggests their clinical utility for monitoring minimal residual disease and recurrent disease, providing prognostic information, and monitoring therapy responses in patients with solid tumors. The Invitae Personalized Cancer Monitoring™ assay uses a patient-specific, tumor-informed variant signature identified through whole exome sequencing to detect ctDNA in peripheral blood of patients with solid tumors. METHODS: The assay's tumor whole exome sequencing and ctDNA detection components were analytically validated using 250 unique human specimens and nine commercial reference samples that generated 1349 whole exome sequencing and cell-free DNA (cfDNA)-derived libraries. A comparison of tumor and germline whole exome sequencing was used to identify patient-specific tumor variant signatures and generate patient-specific panels, followed by targeted next-generation sequencing of plasma-derived cfDNA using the patient-specific panels with anchored multiplex polymerase chain reaction chemistry leveraging unique molecular identifiers. RESULTS: Whole exome sequencing resulted in overall sensitivity of 99.8% and specificity of > 99.9%. Patient-specific panels were successfully designed for all 63 samples (100%) with ≥ 20% tumor content and 24 (80%) of 30 samples with ≥ 10% tumor content. Limit of blank studies using 30 histologically normal, formalin-fixed paraffin-embedded specimens resulted in 100% expected panel design failure. The ctDNA detection component demonstrated specificity of > 99.9% and sensitivity of 96.3% for a combination of 10 ng of cfDNA input, 0.008% allele frequency, 50 variants on the patient-specific panels, and a baseline threshold. Limit of detection ranged from 0.008% allele frequency when utilizing 60 ng of cfDNA input with 18-50 variants in the patient-specific panels (> 99.9% sensitivity) with a baseline threshold, to 0.05% allele frequency when using 10 ng of cfDNA input with an 18-variant panel with a monitoring threshold (> 99.9% sensitivity). CONCLUSIONS: The Invitae Personalized Cancer Monitoring assay, featuring a flexible patient-specific panel design with 18-50 variants, demonstrated high sensitivity and specificity for detecting ctDNA at variant allele frequencies as low as 0.008%. This assay may support patient prognostic stratification, provide real-time data on therapy responses, and enable early detection of residual/recurrent disease.

Computer-Aided Surgery-Navigated, Functional Alignment Total Knee Arthroplasty: A Surgical Technique.

The decision on which technique to use to perform a total knee arthroplasty has become much more complicated over the last decade. The shortfalls of mechanical alignment and kinematic alignment has led to the development of a new alignment philosophy, functional alignment. Functional alignment uses preoperative radiographic measurements, computer-aided surgery, and intraoperative assessment of balance, to leave the patient with the most "normal" knee kinematics achievable with minimal soft-tissue release. The purpose of this surgical technique article is to describe in detail the particular technique needed to achieve these alignment objectives.

Flexion deformity and laxity as a function of knee position at the time of tensioning of rigid anatomic hamstring ACL grafts.

BACKGROUND: Anatomic ACL grafts routinely display the anisometric length-tension behaviour seen in the native ligament with maximum length in full knee extension. Recent improvements in hamstring graft preparation and fixation have improved graft rigidity to the point where total graft lengthening after implantation may be less than 1 mm. Despite this it remains common practice to fix these grafts in a knee flexed position. METHODS: Nineteen participants underwent all-inside ACL reconstruction with optimally preconditioned 4 strand semitendinosus grafts using bi-cortical adjustable suspensory loop fixation. Using a computer navigation system, baseline measures of anisometricity, extension range, and tibial rotation were made. The graft was tensioned and provisionally fixed with the knee flexed 5° beyond its anisometric point and extension range recorded. The graft was then definitively fixed with the knee fully extended and extension range and tibial rotation recorded again. Anterior laxity measurements were made pre-operatively and postoperatively using a manual arthrometer and compared to those from the contralateral limb. RESULTS: Fixing the graft with the knee flexed produced a mean FD of 10.9° (p < 0.0001) and fixing in extension restored full extension (p = 0.661). Fixing in extension restored anterior laxity at 30° (p = 0.224) and at 90° (p = 0.668). There were very strong correlations between post-operative and control extension range (r = 0.931, p < 0.0001) and anterior laxity and 30° (r = 0.830, p < 0.0001) measures. Constraint of tibial internal rotation increased by 2.9° during the pivot-shift (p < 0.001) and increased with pivot shift grade (r = 0.474, p = 0.040). CONCLUSION: Fixing rigid anatomic hamstring grafts in a knee flexed position routinely produces a flexion deformity. Tensioning and fixing grafts with the knee fully extended restores full extension and anterior laxity at 30° and 90°. Rotational constraint is significantly improved and correlates with the pivot-shift grade. CLINICAL RELEVANCE: Rigid anatomic grafts should be tensioned and fixed with the knee fully extended.

Orthopaedic surgeon attitudes towards current limitations and the potential for robotic and technological innovation in arthroscopic surgery.

PURPOSE: To determine the perceptions of surgeons at both consultant and resident level to the difficulties of performing knee arthroscopy and to determine their willingness to adopt robotic technology. METHODS: A questionnaire was designed to discern the attitude of orthopaedic consultants and residents to the technical challenges of performing knee arthroscopy and the possible role of robotically enhanced surgery. The questionnaire included 31 questions across five key domains. RESULTS: Iatrogenic damage to articular cartilage was thought to occur in at least 1 in 10 cases by 50% of respondents with 15% believing that it occurred in every case. One hundred or more procedures were thought to be necessary to overcome the learning curve by 40% of respondents and 77.5% believed that 50 procedures or above were necessary. Ninety-nine per cent of respondents agreed that higher technical skills would decrease unintended damage. Despite such difficulties with the procedure and no prior experience with robotic surgery, 47% of respondents see a role for semiautonomous arthroscopic systems in the future. CONCLUSIONS: Surgeons believe that knee arthroscopy is a difficult procedure with a long learning curve and a high incidence of iatrogenic cartilage damage. Many find it ergonomically challenging and have frustration with current tools and technology. CLINICAL RELEVANCE: This is the first study that highlights surgeons' difficulties performing knee arthroscopy despite the commonly held attitudes that it is a straightforward procedure. Systems that are able to decrease these problems should improve patients' outcomes and decrease the risk of harm.

Takotsubo Cardiomyopathy Associated with Primary Hyperthyroidism Secondary to Toxic Multinodular Goiter.

Takotsubo cardiomyopathy is increasingly recognized as a distinct clinical entity. An association with thyroid disease has been identified in several case reports, mostly in the context of Grave disease. We report the case of a 67-year-old woman presenting with takotsubo cardiomyopathy and thyrotoxicosis secondary to toxic multinodular goiter. Previously unreported, this suggests that this association is related to the direct effects of thyroid hormone, rather than an autoimmune mechanism. Thyroid disease should be considered in patients presenting with takotsubo cardiomyopathy.