Initial Safety of Total Talus Replacement Used to Treat Talar Avascular Necrosis.

BACKGROUND: Total talus replacement (TTR) implants are designed to replace the diseased talar anatomy, reduce pain, maintain ankle range of motion, and restore ankle function after conservative treatments have failed. Currently TTR implants are produced by 3D printing a patient-specific implant designed from the patient's preoperative anatomy. TTR surgery using patient-specific implants is a relatively new technique that remains understudied in the literature. Therefore, the purpose of this investigation was to determine the early safety and potential benefit of the TTR implant in patients with talar avascular necrosis. METHODS: This retrospective, multicenter, cohort study evaluates the safety and potential benefits of TTR using 3D-printed patient-specific implants across 4 US centers. The primary outcome was the occurrence of early adverse events after TTR surgery. Secondary outcomes including, pain, and physical function were assessed using the pain visual analog scale (VAS), and Patient-Reported Outcomes Measurement Information System (PROMIS) physical function (PF), respectively. RESULTS: The study team analyzed 15 patients with more than 1 year of follow-up. The mean duration of follow-up was 25.9 months (range: 18.3-41 months). Although 33.3% (5 of 15) of patients experienced adverse events, primarily occurring within the initial 6 months postoperatively, 93% (14 of 15) of patients reported implant survivorship. Of the 5 cases (33.3%) resulting in an adverse event, 3 (60.0%) were determined to be unrelated to the subject device, 2 (40.0%) were determined to be possibly procedure-related, and none (0%) were determined to be device-related. CONCLUSION: Although further studies are needed to compare TTR with the standard of care, the results of this study demonstrate the relative early safety of TTR surgery using a 3D-printed implant for the treatment of challenging talar pathologies. A larger and longer clinical study is required to see if the efficacy of this approach will be statistically and clinically meaningful.

Association of Extraosseous Arterial Diameter With Talar Dome Osteochondral Lesions.

BACKGROUND: Etiology of osteochondral lesions of the talus (OLT) is multifactorial and may develop from trauma, genetics, or hypovascularity. The talar dome is supplied by the posterior tibial artery (PTA) and, to a lesser degree, the sinus tarsi artery (STA). The role of talar dome hypovascularity on OLT remains poorly studied. We aimed to determine any relationship between the diameter of PTA (dPTA) and STA (dSTA) and the incidence and characteristics of talus OLT. METHODS: This retrospective study included 77 patients with OLT and 77 subjects as a matched control group (age range: 30-40 years). Using magnetic resonance imaging, the dPTA was measured 1 cm above the tibial plafond, at the plafond, and at the level of medial malleolar tip. Likewise, dSTA was measured at the level of the talar neck. The area, volume, depth, localization, and surgical intervention for OLT were recorded as well. RESULTS: The study group had significantly smaller dPTA at all 3 levels (1.05 ± 0.22 mm, 0.99 ± 0.18 mm, 0.98 ± 0.31 mm, proximal to distal, respectively) compared with controls (1.25 ± 0.23 mm, 1.20 ± 0.22 mm, 1.14 ± 0.18 mm, respectively) (P < .001). The dSTA was also significantly smaller in the study group compared with the control group (0.5 ± 0.11 mm vs 0.57 ± 0.08 mm, respectively; P = .001). The mean dPTA (of all 3 levels) cutoff value for predicting the occurrence of OLT was 1.1 mm with 74% sensitivity and 75% specificity. A significant inverse correlation was observed between OLT area and arterial diameters (P < .001). CONCLUSION: Smaller luminal dPTA and dSTA appear to be associated with higher incidence of OLT, with defect size inversely correlated to arterial diameter.

The Emerging Role of Automation, Measurement Standardization, and Artificial Intelligence in Foot and Ankle Imaging: An Update.

In the past few years, advances in clinical imaging in the realm of foot and ankle have been consequential and game changing. Improvements in the hardware aspects, together with the development of computer-assisted interpretation and intervention tools, have led to a noticeable improvement in the quality of health care for foot and ankle patients. Focusing on the mainstay imaging tools, including radiographs, computed tomography scans, and ultrasound, in this review study, the authors explored the literature for reports on the new achievements in improving the quality, accuracy, accessibility, and affordability of clinical imaging in foot and ankle.

The Influence of Talar Displacement on Articular Contact Mechanics: A 3D Finite Element Analysis Study Using Weightbearing Computed Tomography.

BACKGROUND: Talar displacement is considered the main predictive factor for poor outcomes and the development of post-traumatic osteoarthritis after ankle fractures. Isolated lateral talar translation, as previously studied by Ramsey and Hamilton using carbon powder imprinting, does not fully replicate the multidirectional joint subluxations seen in ankle fractures. The purpose of this study was to analyze the influence of multiple uniplanar talar displacements on tibiotalar contact mechanics utilizing weightbearing computed tomography (WBCT) and finite element analysis (FEA). METHODS: Nineteen subjects (mean age = 37.6 years) with no history of ankle surgery or injury having undergone WBCT arthrogram (n = 1) and WBCT without arthrogram (n = 18) were included. Segmentation of the WBCT images into 3D simulated models of bone and cartilage was performed. Three-dimensional (3D) multiple uniplanar talar displacements were simulated to investigate the respective influence of various uniaxial displacements (including lateral translation, anteroposterior translation, varus-valgus angulation, and external rotation) on the tibiotalar contact mechanics using FEA. Tibiotalar peak contact stress and contact area were modeled for each displacement and its gradations. RESULTS: Our modeling demonstrated that peak contact stress of the talus and tibia increased, whereas contact area decreased, with incremental displacement in all tested directions. Contact stress maps of the talus and tibia were computed for each displacement demonstrating unique patterns of pressure derangement. One millimeter of lateral translation resulted in 14% increase of peak talar contact pressure and a 3% decrease in contact area. CONCLUSION: Our model predicted that with lateral talar translation, there is less noticeable change in tibiotalar contact area compared with prior studies whereas external rotation greater than 12 degrees had the largest effect on peak contact stress predictions. LEVEL OF EVIDENCE: Level V, computational simulation study.

Use of Bio-integrative Screws for Fixation of Lisfranc Instability; Pros and Cons from Surgeons' Point of View in a Cadaver Study.

Objectives: Majority of Lisfranc fracture-dislocations require anatomic reduction and rigid internal fixation to prevent debilitating sequelae. Current methods include solid screws and flexible fixations which have been in use for many years. Biointegrative screw is a newer option that has not yet been thoroughly investigated for its effectiveness for Lisfranc injuries. Methods: The ligaments of the Lisfranc complex were resected in eight lower-leg cadaveric specimens. This was done by eight foot and ankle surgeons individually. Distraction forces were applied from opposite sides at the joint to replicate weight bearing conditions. Three methods of fixation - flexible fixation, metal, and biointegrative screws- were evaluated. The diastasis and area at the level of the ligament were measured at four conditions (replicated injury and each type of fixation) in neutral and distraction conditions using fluoroscopy images. The Wilcoxon test and Kruskal Wallis test were used for comparison. P value <0.05 was considered statistically significant. Results: The diastasis value for the transected ligament scenario (2.47 ± 0.51 mm) was greater than those after all three fixation methods without distraction (2.02 ± 0.5 for flexible fixation, 1.72 ± 0.63 mm for metal screw fixation and 1.67 ± 0.77 mm for biointegrative screw fixation). The transected ligament diastasis was also greater than that for metal screw (1.61 ± 1.31mm) and biointegrative screws (1.69 ± 0.64 mm) with distraction (p<0.001). The area at the level of the ligament showed higher values for transected ligament (32.7 ± 13.08 mm2) than the three fixatives (30.75 ± 7.42 mm2 for flexible fixation, 30.75 ± 17.13 mm2 for metal screw fixation and 29.53 ± 9.15 mm2 for biointegrative screw fixation; p<0.05). Conclusion: Metal screws, flexible fixation and biointegrative screws showed comparable effectiveness intra-op, in the correction of diastasis created as a consequence of Lisfranc injury.

Does Screw Order Matter? A Technique Tip to Prevent Loss of Fracture Reduction during Surgical Fixation of Lateral Malleolus Fractures.

When obtaining surgical fixation of lateral malleolus fractures, a cortical lag screw is commonly used to obtain anatomic reduction. Subsequently, a neutralization plate is applied. Slight loss of fracture reduction after plate placement occasionally occurs. Although this is frequently attributed to poor bone quality or suboptimal initial lag screw fixation, a frequently overlooked factor is screw order when applying the neutralization plate. The purpose of this technique tip is to highlight the biomechanical rationale behind this loss of reduction and advocate a specific screw order for lateral malleolus fixation.

The Emerging Role of Automation, Measurement Standardization, and Artificial Intelligence in Foot and Ankle Imaging: An Update.

In the past few years, advances in clinical imaging in the realm of foot and ankle have been consequential and game changing. Improvements in the hardware aspects, together with the development of computer-assisted interpretation and intervention tools, have led to a noticeable improvement in the quality of health care for foot and ankle patients. Focusing on the mainstay imaging tools, including radiographs, computed tomography scans, and ultrasound, in this review study, the authors explored the literature for reports on the new achievements in improving the quality, accuracy, accessibility, and affordability of clinical imaging in foot and ankle.

Lack of Surgeon Standardization on Implant Selection in Ankle Fracture Fixation May Increase Costs and Decrease Contribution Margin.

BACKGROUND: Surgical standardization has been shown to decrease costs without impacting quality; however, there is limited literature on this subject regarding ankle fracture fixation. Methods. Between October 5, 2015 and September 27, 2017, a total of 168 patients with isolated ankle fractures who underwent open reduction, internal fixation (ORIF) were analyzed. Financial data were analyzed across ankle fracture classification type, implant characteristics, and surgeons. Bivariate analyses were conducted. One-way analysis of variance was used to compare hardware costs across all 5 surgeons. Linear regression analysis was used to determine if hardware cost differed by surgeon when accounting for fracture type. RESULTS: The mean contribution margin was $4853 (SD $6446). There was a significant difference in implant costs by surgeon (range, lowest-cost surgeon: $471 [SD $283] to $1609 [SD $819]; P < .001). There was no difference in the use of a suture button or locking plate by fracture type (P = .13); however, the cost of the implant was significantly higher if a suture button or locking plate was used ($1014 [SD $666] vs $338 [SD $176]; P < .001). There was an association between surgeon 3 (ß = 200.32 [95% CI 6.18-394.47]; P = .043) and surgeon 4 (ß = 1131.07 [95% CI 906.84-1355.30]; P < .001) and higher hardware costs. CONCLUSIONS: Even for the same ankle fracture type, a wide variation in implant costs exists. The lack of standardization among surgeons accounted for a nearly 3.5-fold difference, on average, between the lowest- and highest-cost surgeons, negatively affecting contribution margin. LEVELS OF EVIDENCE: Level IV.

Development of a Novel Ulcerative Colitis Endoscopic Mayo Score Prediction Model Using Machine Learning.

Background and Aims: Endoscopic assessment is a co-primary end point in inflammatory bowel disease registration trials, yet it is subject to inter- and intraobserver variability. We present an original machine learning approach to Endoscopic Mayo Score (eMS) prediction in ulcerative colitis and report the model's performance in differentiating key levels of endoscopic disease activity on full-length procedure videos. Methods: Seven hundred ninety-three full-length videos with centrally-read eMS were obtained from 249 patients with ulcerative colitis, who participated in a phase II trial evaluating mirikizumab (NCT02589665). A video annotation approach was established to extract mucosal features and associated eMS classification labels from each video to be used as inputs for model training. The primary objective of the model was a categorical prediction of inactive vs active endoscopic disease evaluated against 2 independent test sets: a full set with a baseline single human expert read and a consensus subset in which 2 human reads agreed. Results: On the full test set of 147 videos, the model predicted inactive vs active endoscopic disease via the eMS with an area under the curve of 89%, accuracy of 84%, positive predictive value of 80%, and negative predictive value of 85%. In the consensus test set of 94 videos, the model predicted inactive vs active endoscopic disease with an area under the curve of 92%, accuracy of 89%, positive predictive value of 87%, and negative predictive value of 90%. Conclusion: We have demonstrated that this machine learning model supervised by mucosal features and eMS video annotations accurately differentiates key levels of endoscopic disease activity.

Screw-only fibular construct for Weber B ankle fractures: A retrospective clinical and cost comparison to assess feasibility for resource-limited settings.

INTRODUCTION: Ankle fractures are one of the most common injuries sustained worldwide, with the majority being isolated lateral malleolus fractures. The majority of the world's population live in Low and Middle Income Countries (LMIC), where implant cost may limit surgical treatment of ankle fractures. We investigate if Weber B ankle fractures could be effectively treated with a lower-cost technique using two screws between the fibula and the tibia to neutralize an interfragmentary lag screw. METHODS: After IRB approval, consecutive patients from January 1, 2020 to December 31, 2020 with Weber-B ankle fractures were treated using AO technique (AOT) with plate osteosynthesis neutralizing an interfragmentary screw. Syndesmotic injuries, as well as injuries to the medial malleolus or foot were treated according to the surgeon's preferences. From January 1, 2021 to December 31, 2021 these injuries were treated with a screw-only technique (SOT) with two fibula pro tibia screws to neutralize an interfragmentary screw. Patient demographics including age, sex, BMI, smoking status, associated rheumatoid arthritis, and associated diabetes mellitus were recorded. The primary outcome variable was a stable radiographic mortise at six weeks post-surgery, secondary outcome variables included clinical union, infection, hardware removal, and implant cost for lateral malleolar fixation charged to the hospital. RESULTS: Seventeen AOT and 10 SOT constructs were included. Demographic characteristics were similar between groups. All fractures maintained a stable mortise with clinical union at 6 weeks without infection. There was a statistically significant difference in hardware removal (17.6% AOT, 50% SOT, p = 0.012). The average implant cost to the hospital of the lateral malleolar fixation was significantly less in the SOT group ($592 (SD $229)), compared to the AOT group ($1,949.97 (SD $562)), (p < 0.0001). CONCLUSION: We introduce proof of concept of a novel lower-cost fixation strategy for Weber B ankle fractures that maintained a stable mortise with clinical union at six weeks post-surgery. However, there was a significantly higher rate of hardware removal following fixation with a screw-only construct.

The Lateral Drawer Test: A New Clinical Test to Assess Mortise Instability in Weber B Fibula Fractures.

Background: Assessment of mortise stability is paramount in determining appropriate management of ankle fractures. Although instability is readily apparent in bimalleolar or trimalleolar ankle fractures, determination of instability in the isolated Weber B fibula fracture often requires further investigation. Prior authors have demonstrated poor predictive value of physical examination findings such as tenderness, ecchymosis, and swelling with instability. The goal of this study is to test the validity of a new clinical examination maneuver, the lateral drawer test, against the gravity stress view (GSV) in a cohort of patients with Weber B fibula fractures. Secondary goals included assessing pain tolerability of the lateral drawer test, as well as testing interobserver reliability. Methods: Sixty-two patients presenting with isolated fibula fractures were prospectively identified by an orthopaedic nurse practitioner or resident. Three nonweightbearing radiographic views of the ankle as well as a GSV were obtained. Radiographs were not visualized before conducting the lateral drawer test. Two foot and ankle fellowship-trained orthopaedic surgeons performed and graded the lateral drawer test. Radiographs were then examined and medial clear space (MCS) was measured. Visual analog scale (VAS) pain scores were obtained before and after testing. The results of the lateral drawer test were compared with radiographic measurements of MCS on GSV. A cadaveric experiment was devised to assess interobserver reliability of the lateral drawer test. Results: Thirty (48%) of 62 consecutively enrolled patients demonstrated radiographic instability with widening of the MCS ≥5 mm on GSV. When correlated with MCS measurement, the lateral drawer test demonstrated a sensitivity of 83%, specificity of 97%, positive predictive value (PPV) of 96%, and negative predictive value (NPV) of 86%. There was a strong correlation between the lateral drawer test grade and amount of MCS widening (Spearman correlation ρ = 0.82, P < .005). Patients tolerated the maneuver well with an average increase of 0.7 on the VAS pain scale. Testing of 2 observers utilizing the cadaveric model demonstrated a Cohen's Kappa coefficient of 0.7 indicating moderate interobserver agreement. Conclusion: The lateral drawer test demonstrates high sensitivity, specificity, PPV, and NPV with moderate interobserver reliability compared with the MCS on GSV in patients presenting with Weber B fibula fractures. Although further external validation is required, the lateral drawer test may offer an adjunct tool via physical examination to help determine mortise stability. Level of Evidence: Level II, Prospective Cohort Study.

The Lateral Fibular Stress Test: High Variability of Force Applied by Orthopaedic Surgeons in a Biomechanical Model.

Background: The lateral fibular stress test (LFST), also known as the hook or Cotton test, is commonly performed to assess syndesmotic instability intraoperatively. Several studies have used 100 N as the force applied when performing the LFST to detect syndesmotic instability, though no evidence-based requisite force has been described for the test. We hypothesize that surgeons do not apply force uniformly or consistently when performing the LFST and that substantial variation exists. Fundamentally, this could lead to inconsistent diagnosis of syndesmotic instability as surgeons may not be applying the force in a consistent manner. Methods: A biomechanical ankle model consisting of an industrial force gauge attached through a SawBones model was fashioned. Orthopaedic attending surgeons and trainees were asked to perform a series of LFSTs and to simulate the force they typically apply intraoperatively. Basic demographic data were collected on each participant. Results: Thirty-three surgeons participated in the study, including 18 trainees. The median (IQR) force applied during the LFST was 96.42 (71.42-126.33), 87.49 (69.19-117.40), 99.99 (79.91-137.49), for the pooled group, attendings, and trainees respectively. More than half (54.5%) of all trials were less than 100 N (57.8% of surgeons, 51.8% trainees). Intraobserver correlation was excellent within the overall cohort (0.92, P < .001), trainees (0.90, P < .001), and attendings (0.94, P < .001), respectively. Interobserver reliability was fair among the overall cohort (κ =0.28, P = .49), and poor between the attendings (κ = 0.11, P = .69) and the trainees (κ = 0.05, P = .82), respectively. Conclusion: Our study demonstrates that the amount of force applied by typical surgeons when performing the LFST test is highly variable. Variable force application when performing the LFST may lead to inconsistent detection of syndesmotic instability, which may portend a poorer outcome. Clinical Relevance: In this study, we demonstrate the wide variability in the amount of force used during a lateral fibular stress test. High variability of force application when performing the LFST may lead to inconsistent diagnosis of syndesmotic instability, which may portend a poorer outcome. Our findings suggest the need for further investigation into the technical aspects of syndesmotic testing that will permit more reproducible and valid interrogation of the syndesmosis.

Revision Strategies for the Aseptic, Malaligned, Surgically Treated Ankle Fracture.

Although surgical fixation can take many forms depending on ankle fracture morphology, the goals of open reduction internal fixation are to restore fracture alignment, re-establish ankle stability, and achieve an anatomic mortise. A subset of patients may present postoperatively with evidence of suboptimal open reduction internal fixation. Increased contact pressures across the tibiotalar joint, increased talar shift, and pathologic joint loading leading to the development of post-traumatic arthritis are common sequela of the malaligned mortise. Treatment necessitates a comprehensive approach. This article describes our preferred systematic approach for diagnosis and treatment of the aseptic, malaligned, surgically treated ankle fracture.

Are SER-II Ankle Fractures Anatomic? Computed Tomography Demonstrates Mortise Malalignment in the Setting of Apparently Normal Radiographs.

BACKGROUND: Ankle fracture treatment is predicated on minimal displacement, leading to abnormal joint contact area. The purpose of this investigation is to determine whether computed tomography (CT) detects subtle mortise malalignment undetectable by x-ray in supination-external rotation-II (SER-II) injuries. METHODS: A total of 24 patients with SER-II injuries, as demonstrated by negative gravity stress radiography, were included. Medial clear space (MCS) measurements were performed on bilateral ankle x-rays (injured and contralateral, uninjured side) at several time points as well as bilateral non-weight-bearing CT performed once clinical and radiographic healing was demonstrated (mean = 66 days post injury, range = 61-105 days). Statistical analyses examined differences in measurements between both sides. RESULTS: Final x-rays demonstrated no differences between normal and injured ankle MCS (P = .441). However, CT coronal/axial MCS measurements were different (P < .05). CT coronal MCS measured wider by a mean difference of 0.67 mm (P < .001). CONCLUSION: There is a high incidence of subtle mortise malalignment in SER-II ankle fractures, as demonstrated by CT, which is undetectable when assessed by plain radiographs. Although clinical outcomes are yet unknown, there are important implications of the finding of confirmed, subtle mortise malalignment in SER-II injuries and the limitations of x-ray to detect it. LEVEL OF EVIDENCE: Level III.