Comparing the Interobserver Reliability of 4 Methods Used to Measure Knee Laxity on Coronal Plane Stress Radiograph.

Background: Varus and valgus knee stress radiographs provide valuable information in the pre- and postoperative evaluation of joint laxity in patients with multiligament knee injuries (MLKIs). Purpose: To review the literature for described techniques of quantifying laxity on coronal stress radiographs of the knee and identify the most reliable method. Study Design: Cohort study (diagnosis); Level of evidence, 3. Methods: A thorough literature search using the MEDLINE and Embase databases identified 4 studies with distinct methods for objectively measuring laxity on varus and valgus stress radiographs: Heesterbeek et al (2008), Jacobsen (1976), LaPrade et al (2004), and Sawant et al (2004). To compare these methods, 200 coronal plane stress radiographs from 50 patients with MLKIs were retrospectively reviewed from an MLKI database at a single institution. The amount of varus and valgus laxity on each radiograph was measured independently by 4 reviewers using each method. Intraclass correlation coefficients (ICCs) with 95% CIs were calculated to assess the interobserver reliability of each method overall and the varus and valgus measurements individually. Results: For all 4 methods, the overall interobserver reliability was considered at least moderate. The method by Heesterbeek et al proved to have the highest interrater reliability in all domains-overall (ICC, 0.87 [95% CI, 0.85-0.90]), valgus (ICC, 0.83 [95% CI, 0.78-0.88]), and varus (ICC, 0.87 [95% CI, 0.83-0.90])-demonstrating good to excellent reliability both overall and in varus measurements and showing good reliability in valgus measurements. The method by Sawant et al demonstrated good reliability in valgus measurements. All other measures demonstrated moderate reliability. Conclusion: Available methods for measuring knee joint laxity on varus and valgus knee stress radiographs in patients with MLKIs demonstrated moderate to good interobserver reliability. The method described by Heesterbeek et al proved to have the highest reliability overall as well as in measurements on varus and valgus views individually.

Probing the Mechanical Properties of 2D Materials via Atomic-Force-Microscopy-Based Modulated Nanoindentation.

As the field of low-dimensional materials (1D or 2D) grows and more complex and intriguing structures are continuing to be found, there is an emerging need for techniques to characterize the nanoscale mechanical properties of all kinds of 1D/2D materials, in particular in their most practical state: sitting on an underlying substrate. While traditional nanoindentation techniques cannot accurately determine the transverse Young's modulus at the necessary scale without large indentations depths and effects to and from the substrate, herein an atomic-force-microscopy-based modulated nanomechanical measurement technique with Angstrom-level resolution (MoNI/ÅI) is presented. This technique enables non-destructive measurements of the out-of-plane elasticity of ultra-thin materials with resolution sufficient to eliminate any contributions from the substrate. This method is used to elucidate the multi-layer stiffness dependence of graphene deposited via chemical vapor deposition and discover a peak transverse modulus in two-layer graphene. While MoNI/ÅI has been used toward great findings in the recent past, here all aspects of the implementation of the technique as well as the unique challenges in performing measurements at such small resolutions are encompassed.

Stiffness anisotropy coordinates supracellular contractility driving long-range myotube-ECM alignment.

In skeletal muscle tissue, injury-related changes in stiffness activate muscle stem cells through mechanosensitive signaling pathways. Functional muscle tissue regeneration also requires the effective coordination of myoblast proliferation, migration, polarization, differentiation, and fusion across multiple length scales. Here, we demonstrate that substrate stiffness anisotropy coordinates contractility-driven collective cellular dynamics resulting in C2C12 myotube alignment over millimeter-scale distances. When cultured on mechanically anisotropic liquid crystalline polymer networks (LCNs) lacking topographic features that could confer contact guidance, C2C12 myoblasts collectively polarize in the stiffest direction of the substrate. Cellular coordination is amplified through reciprocal cell-ECM dynamics that emerge during fusion, driving global myotube-ECM ordering. Conversely, myotube alignment was restricted to small local domains with no directional preference on mechanically isotropic LCNs of same chemical formulation. These findings reveal a role for stiffness anisotropy in coordinating emergent collective cellular dynamics, with implications for understanding skeletal muscle tissue development and regeneration.

Offloading Plantar Pressures in Healthy Adults: Stirrup Cast vs Total Contact Cast.

BACKGROUND: Diabetic foot ulcers are associated with significant morbidity and mortality while posing a challenge for healthcare professionals. Offloading is considered the mainstay of treatment. Total contact casting (TCC) is widely used but does not effectively offload the hindfoot. Some studies suggest that a metal stirrup is effective at offloading midfoot and hindfoot ulcers. The primary purpose of this study is to compare the offloading mechanism of TCC to a stirrup cast. METHODS: A pilot observational study assessing 12 healthy volunteers who underwent casting with a TCC or stirrup cast. A sensor (Pedar; Novel GmbH) that measures maximum force, peak pressure, and contact time and area of each foot region, was placed inside the cast to assess the offloading mechanisms of the 2 interventions. RESULTS: We measured a reduction in all plantar foot loading parameters from the TCC to the stirrup cast. The highest reductions of 85% to 96% (±5%-13%) were noted in maximum force and peak pressure under the forefoot (P < .0001) and found reductions in maximum force, the contact area of all regions of the foot, peak pressure and contact time of the forefoot and midfoot, and contact area of the hindfoot (P < .05). CONCLUSION: In this experimental trial of healthy adults, the stirrup cast was more effective than the TCC by offloading the foot mostly in the forefoot and midfoot.

Two-Year Outcomes After Total Ankle Replacement With a Novel Fixed-Bearing Implant.

BACKGROUND: The Integra Cadence total ankle replacement (TAR) is a fourth-generation anatomic, fixed-bearing implant requiring minimal tibial and talar resection, which has been in clinical use since June 2016. The primary purpose of this study is to assess its short-term clinical and radiographic outcomes after TAR using this prosthesis. METHODS: This is a prospective case series of consecutive patients that underwent TAR using this novel fourth-generation prosthesis between June 2016 and November 2017. The primary outcome of interest was the Ankle Osteoarthritis Scale (AOS). Secondary outcomes included Short Form Health Survey-36 (SF-36) scores, radiographic alignment, complications, reoperations, and revisions. RESULTS: In total, 69 patients were included in our study. Fifty-one patients (73.9%) required a total of 91 ancillary procedures. Postoperatively, AOS pain scores decreased significantly by an average of 17.8±30.1 points from 45.9±18.2 to 28.4±27.3 (P < .001). AOS disability scores also decreased significantly following surgery by an average of 22.0±30.5 points from 53.9±18.5 to 32.5±27.9 (P < .001). The SF-36 physical component summary score improved 10.4±9.8 points from 33.1±9.1 to 42.6±9.1 (P < .001). Radiographic analysis demonstrated significant improvement to neutral coronal plane alignment, which was achieved in 97% of patients (P < .01) with no cyst formation at 2 years. There was 1 reported complication, 9 reoperations, and no metal or polyethylene component revisions. Overall, the 2-year implant survivorship was 100% in our cohort. Eighteen patients (26.1%) demonstrated fibrous ingrowth of the tibial component. However, outcome scores for these patients did not demonstrate any negative effects. CONCLUSION: In our hands, this TAR system demonstrated excellent early clinical and radiographic outcomes. Patients reported improved physical health status, pain, and disability in the postoperative period. Total ankle instrumentation allowed for accurate and reproducible implantation with correction of coronal and sagittal plane deformities. Early results for the clinical use of this TAR system are promising, but further long-term prospective outcome studies are necessary. LEVEL OF EVIDENCE: Level IV, case series.

Living With Both a Total Ankle Replacement and an Ankle Fusion: A Qualitative Study From the Patients' Perspective.

BACKGROUND: Total ankle replacement (TAR) and ankle fusion are effective treatments for end-stage ankle arthritis. Comparative studies elucidate differences in treatment outcomes; however, the literature lacks evidence demonstrating what outcomes are important to patients. The purpose of this study was to investigate patients' experiences of living with both a TAR and ankle fusion. METHODS: This research study used qualitative description. Individuals were selected from a cohort of patients with TAR and/or ankle fusion (n = 1254). Eligible patients were English speaking with a TAR and contralateral ankle fusion, and a minimum of 1 year since their most recent ankle reconstruction. Surgeries were performed by a single experienced surgeon, and semistructured interviews were conducted by a single researcher in a private hospital setting or by telephone. Ankle Osteoarthritis Scale (AOS) scores, radiographs, and ancillary surgical procedures were collected to characterize patients. Themes were derived through qualitative data analysis. RESULTS: Ten adults (8 men, 2 women), ages 59 to 90 years, were included. Average AOS pain and disability scores were similar for both surgeries for most patients. Participants discussed perceptions of each reconstructed ankle. Ankle fusions were considered stable and strong, but also stiff and compromising balance. TARs were considered flexible and more like a "normal ankle," though patients expressed concerns about their TAR "turning" on uneven ground. Individuals applied this knowledge to facilitate movement, particularly during a first step and transitioning between positions. They described the need for careful foot placement and attention to the environment to avoid potential challenges. CONCLUSION: This study provides insight into the experiences of individuals living with a TAR and ankle fusion. In this unusual but limited group of patients, we found that each ankle reconstruction was generally perceived to have different characteristics, advantages, and disadvantages. Most participants articulated a preference for their TAR. These findings can help clinicians better counsel patients on expectations after TAR and ankle fusion, and improve patient-reported outcome measures by better capturing meaningful outcomes for patients. LEVEL OF EVIDENCE: Level IV, case series.

Safety and Effectiveness of Outpatient Total Ankle Arthroplasty.

BACKGROUND: Total ankle arthroplasty (TAA) is a surgical procedure commonly reserved for patients suffering from symptomatic end-stage ankle arthritis. As the number of TAAs increases, so does the associated economic burden. Given these economic constraints, there has been interest in the feasibility of outpatient TAA. The purpose of this study is to evaluate the safety, efficacy, and satisfaction of patients undergoing outpatient TAA. METHODS: This is a retrospective case series of consecutive patients who underwent outpatient TAA from July 2018 to June 2019. Inclusion criteria included any patient undergoing a primary TAA in the outpatient setting. This was defined as discharge on the same day of surgery or within 12 hours of surgery. All surgeries were completed by a single experienced surgeon through an anterior approach using the Cadence Total Ankle System. Prior to surgery, all patients received a popliteal nerve block. Patients were then discharged home with oral analgesic and a popliteal nerve catheter, which they removed after 48 hours. The primary outcome of interest was postoperative pain control, which was measured using a numeric scale. Secondary outcomes included complication rate, readmission rate, and patient satisfaction. A review of the current literature was then completed to supplement our results. RESULTS: In total, 41 patients were included in our analysis. In terms of the primary outcome, the average numeric scale score was 1.98, indicating excellent pain control. Additionally, nearly all 41 patients stated they were very satisfied with their postoperative pain control regimen. In terms of secondary outcomes, the majority of patients stated they were satisfied with discharge on the same day as surgery. There were no readmissions or major complications in our outpatient TAA cohort. When asked if they would recommend the care they experienced to a friend with the same condition, 95% of patients said that they would recommend this care pathway. Our literature review included 5 original studies, which were all retrospective level IV studies. These studies uniformly demonstrated the safety and efficacy of outpatient TAA. CONCLUSIONS: The results of our study demonstrate the outpatient TAA is associated with excellent pain control using a multidisciplinary pain approach. The use of standardized outpatient postoperative pathways was effective in preventing readmissions and complications, while still resulting in high patient satisfaction scores. A review of the literature complemented our results, as there are largely no significant differences between outpatient and inpatient TAA.Level of Evidence: Level IV, case series.