Osteotomies around the knee alter alignment of the ankle and hindfoot: a systematic review of biomechanical and clinical studies

Purpose: Emerging reports suggest an important involvement of the ankle/hindfoot alignment in the outcome of knee osteotomy; however, a comprehensive overview is currently not available. Therefore, we systematically reviewed all studies investigating biomechanical and clinical outcomes related to the ankle/hindfoot following knee osteotomies. Methods: A systematic literature search was conducted on PubMed, Web of Science, EMBASE and Cochrane Library according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and registered on international prospective register of systematic reviews (PROSPERO) (CRD42021277189). Combining knee osteotomy and ankle/hindfoot alignment, all biomechanical and clinical studies were included. Studies investigating knee osteotomy in conjunction with total knee arthroplasty and case reports were excluded. The QUality Appraisal for Cadaveric Studies (QUACS) scale and Methodological Index for Non-Randomized Studies (MINORS) scores were used for quality assessment. Results: Out of 3554 hits, 18 studies were confirmed eligible, including 770 subjects. The minority of studies (n = 3) assessed both high tibial- and distal femoral osteotomy. Following knee osteotomy, the mean tibiotalar contact pressure decreased (n = 4) except in the presence of a rigid subtalar joint (n = 1) or a talar tilt deformity (n = 1). Patient symptoms and/or radiographic alignment at the level of the ankle/hindfoot improved after knee osteotomy (n = 13). However, factors interfering with an optimal outcome were a small preoperative lateral distal tibia angle, a small hip–knee–ankle axis (HKA) angle, a large HKA correction (>14.5°) and a preexistent hindfoot deformity (>15.9°). Conclusions: Osteotomies to correct knee deformity alter biomechanical and clinical outcomes at the level of the ankle/hindfoot. In general, these changes were beneficial, but several parameters were identified in association with deterioration of ankle/hindfoot symptoms following knee osteotomy

Correction of ankle varus deformity using patient-specific dome-shaped osteotomy guides designed on weight-bearing CT : a pilot study

Background Dome-shaped supramalleolar osteotomies are a well-established treatment option for correcting ankle deformity. However, the procedure remains technically demanding and is limited by a two-dimensional (2D) radiographic planning of a three-dimensional (3D) deformity. Therefore, we implemented a weight-bearing CT (WBCT) to plan a 3D deformity correction using patient-specific guides. Methods A 3D-guided dome-shaped supramalleolar osteotomy was performed to correct ankle varus deformity in a case series of five patients with a mean age of 53.8 years (range 47-58). WBCT images were obtained to generate 3D models, which enabled a deformity correction using patient-specific guides. These technical steps are outlined and associated with a retrospective analysis of the clinical outcome using the EFAS score, Foot and Ankle Outcome Score (FAOS) and visual analog pain scale (VAS). Radiographic assessment was performed using the tibial anterior surface angle (TAS), tibiotalar angle (TTS), talar tilt angle (TTA), hindfoot angle (HA), tibial lateral surface angle (TLS) and tibial rotation angle (TRA). Results The mean follow-up was 40.8 months (range 8-65) and all patients showed improvements in the EFAS score, FAOS and VAS (p 0.05). Conclusion Dome-shaped supramalleolar osteotomies using 3D-printed guides designed on WBCT are a valuable option in correcting ankle varus deformity and have the potential to mitigate the technical drawbacks of free-hand osteotomies

Three-dimensional correction of fibular hemimelia using a computer-assisted planning : technical report and literature review

The purpose of this study is to investigate a stepwise approach to translate the principles of deformity correction from 2D plain radiographs to a 3D computer assisted pre-operative planning (CAP), when treating a complex case of fibular hemimelia. Computed tomography slices were used to perform a 3D reconstruction of the deformity. CAP determined the different axes and apex of deformity based on geometrical functions of the software. The obtuse angle was computed and used to determine the concomitant osteotomy angle. An additional review of the literature was performed, allowing comparison towards the current treatment approaches. The pre- and post-operative clinical and radiographic follow up is reported. The computer assisted planning was applicable in a complex fibular hemimelia deformity. The literature review demonstrated no previous use of a 3D computer assisted planning. This case report provides a feasible and effective method to convert the principles of deformity planning from a 2D to a 3D setting. The added value of this technique for clinical practice should be confirmed in further prospective studies

Bilateral comparison of the three-dimensional configuration in the normal ankle syndesmosis : a non-weightbearing and weightbearing CT-analysis

CATEGORY: Ankle INTRODUCTION/PURPOSE: Syndesmotic ankle injuries can be present in up to one-fifth of all ankle trauma and may lead to syndesmotic instability or posttraumatic ankle osteoarthirtis on the long term. It remains challenging to distinguish syndesmotic ankle injuries from other types of ankle trauma. Currently, diagnosis is based on plain radiographs by comparing 2D measurements of the injured to the non-injured side. However, it is unclear to what extent the 3D configuration of the normal ankle syndesmosis is symmetrical during non- or weightbearing conditions. Therefore, our aim was two-fold (1) to establish reference values based on three-dimensional side-to-side comparison of the normal ankle syndesmosis imaged by a non-weightbearing (NWBCT) and weightbearing CT (WBCT) (2) to compare measurements obtained from a NWBCT with those of a WBCT. METHODS: In this retrospective comparative cohort study, patients with a NWBCT (N=38; Mean age=51+-17.4 years) and WBCT (N=43; Mean age=48+-14.3 years) were analyzed. Inclusion criteria were a bilateral NWBCT or WBCT of the foot and ankle between January 2016 and December 2018. Exclusion criteria consisted of hindfoot pathology and an age 75 years. CT images were segmented to obtain 3D models. Computer Aided Design (CAD) operations were used to mirror the left ankle and superimpose it over the right ankle (Fig. 1A). The apex of the lateral malleolus (AML), anterior tubercle (ATF) and posterior tubercle (PTF) were determined. The difference in the coordinates attached to these anatomical landmarks of the left distal fibula in the ankle syndesmosis with respect to the right were used to establish reference values within two standard deviations. The Mann-Whitney U-test was used to compare measurements from a NWBCT with a WBCT. RESULTS: Reference values within two standard deviations are given for each 3D measurement derived from a NWBCT and WBCT-scan (Fig 1B). The highest difference in translation was detected in the anterior-posterior direction (Mean APNWBCT= 0.161mm; 2SD=3.212/ Mean APWBCT= -0.082mm; 2SD=2.374). The highest difference in rotation was detected in the external- internal direction (Mean EINWBCT= -0.484°; 2SD=8.720/ Mean EIWBCT= -0,326°; 2SD=5.370). None of these differences were statistically significant in the normal ankle syndesmosis when obtained from a NWBCT scan compared to a WBCT scan (P>0.05). CONCLUSION: This study provides reference values of the three-dimensional configuration in the normal ankle syndesmosis based on side-to-side comparison. It did not demonstrate significant differences in the normal ankle syndesmosis between NWBT and WBCT scans. These novel 3D data contribute relevantly to previously established bilateral 2D radiographic reference values. In clinical practice, they will aid in distinguishing if a patient with a syndesmotic ankle lesion differs from normal variance in syndesmotic ankle symmetry

The hind- and midfoot alignment computed after a medializing calcaneal osteotomy using a 3D weightbearing CT

Purpose: A medializing calcaneal osteotomy (MCO) is a surgical procedure frequently performed to correct an adult acquired flatfoot (AAFD) deformity. However, most studies are limited to a 2D analysis of 3D deformity. Therefore, the aim is to perform a 3D assessment of the hind- and midfoot alignment using a weightbearing CT (WBCT) preoperatively as well as postoperatively. Methods: Eighteen patients with a mean age of 49.4years (range 18-67) were prospectively included in a pre-post-study design. A MCO was performed and a WBCT was obtained pre- and postoperative. Images were converted into 3D models to compute linear and angular measurements, respectively, in millimeters (mm) and degrees (degrees), based on previously reported landmarks of the hind- and midfoot alignment. A regression analysis was performed between the displacement of a MCO and the obtained postoperative correction. Results: The mean 3D hindfoot angle improved significantly preoperative compared to postoperative (p0.05). Conclusion: This study demonstrates an effective 3D correction of an AAFD by a MCO according to a linear relationship. The concomitant formula can be used to perform a preoperative planning. The novelty is the comparative 3D weightbearing CT assessment of both the computed hind- and midfoot alignment after a medializing calcaneus osteotomy. This could improve accuracy of the currently performed preoperative planning in clinical practice

Osteotomies around the knee alter alignment of the ankle and hindfoot : a systematic review of biomechanical and clinical studies

Abstract: center dot Purpose: Emerging reports suggest an important involvement of the ankle/hindfoot alignment in the outcome of knee osteotomy; however, a comprehensive overview is currently not available. Therefore, we systematically reviewed all studies investigating biomechanical and clinical outcomes related to the ankle/hindfoot following knee osteotomies.center dot Methods: A systematic literature search was conducted on PubMed, Web of Science, EMBASE and Cochrane Library according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and registered on international prospective register of systematic reviews (PROSPERO) (CRD42021277189). Combining knee osteotomy and ankle/hindfoot alignment, all biomechanical and clinical studies were included. Studies investigating knee osteotomy in conjunction with total knee arthroplasty and case reports were excluded. The QUality Appraisal for Cadaveric Studies (QUACS) scale and Methodological Index for Non-Randomized Studies (MINORS) scores were used for quality assessment.center dot Results: Out of 3554 hits, 18 studies were confirmed eligible, including 770 subjects. The minority of studies (n = 3) assessed both high tibial-and distal femoral osteotomy. Following knee osteotomy, the mean tibiotalar contact pressure decreased (n = 4) except in the presence of a rigid subtalar joint (n = 1) or a talar tilt deformity (n =1). Patient symptoms and/or radiographic alignment at the level of the ankle/hindfoot improved after knee osteotomy (n = 13). However, factors interfering with an optimal outcome were a small preoperative lateral distal tibia angle, a small hip-knee-ankle axis (HKA) angle, a large HKA correction (>14.5 degrees) and a preexistent hindfoot deformity (>15.9 degrees).center dot Conclusions: Osteotomies to correct knee deformity alter biomechanical and clinical outcomes at the level of the ankle/hindfoot. In general, these changes were beneficial, but several parameters were identified in association with deterioration of ankle/hindfoot symptoms following knee osteotomy

Personalized statistical modeling of soft tissue structures in the knee

Background and Objective: As in vivo measurements of knee joint contact forces remain challenging, computational musculoskeletal modeling has been popularized as an encouraging solution for non-invasive estimation of joint mechanical loading. Computational musculoskeletal modeling typically relies on laborious manual segmentation as it requires reliable osseous and soft tissue geometry. To improve on feasibility and accuracy of patient-specific geometry predictions, a generic computational approach that can easily be scaled, morphed and fitted to patient-specific knee joint anatomy is presented.Methods: A personalized prediction algorithm was established to derive soft tissue geometry of the knee, originating solely from skeletal anatomy. Based on a MRI dataset (n = 53), manual identification of soft-tissue anatomy and landmarks served as input for our model by use of geometric morphometrics. Topographic distance maps were generated for cartilage thickness predictions. Meniscal modeling relied on wrapping a triangular geometry with varying height and width from the anterior to the posterior root. Elastic mesh wrapping was applied for ligamentous and patellar tendon path modeling. Leave-one-out validation experiments were conducted for accuracy assessment.Results: The Root Mean Square Error (RMSE) for the cartilage layers of the medial tibial plateau, the lateral tibial plateau, the femur and the patella equaled respectively 0.32 mm (range 0.14-0.48), 0.35 mm (range 0.16-0.53), 0.39 mm (range 0.15-0.80) and 0.75 mm (range 0.16-1.11). Similarly, the RMSE equaled respectively 1.16 mm (range 0.99-1.59), 0.91 mm (0.75-1.33), 2.93 mm (range 1.85-4.66) and 2.04 mm (1.88-3.29), calculated over the course of the anterior cruciate ligament, posterior cruciate ligament, the medial and the lateral meniscus.Conclusion: A methodological workflow is presented for patient-specific, morphological knee joint modeling that avoids laborious segmentation. By allowing to accurately predict personalized geometry this method has the potential for generating large (virtual) sample sizes applicable for biomechanical research and improving personalized, computer-assisted medicine

MedShapeNet -- A Large-Scale Dataset of 3D Medical Shapes for Computer Vision

16 pagesPrior to the deep learning era, shape was commonly used to describe the objects. Nowadays, state-of-the-art (SOTA) algorithms in medical imaging are predominantly diverging from computer vision, where voxel grids, meshes, point clouds, and implicit surface models are used. This is seen from numerous shape-related publications in premier vision conferences as well as the growing popularity of ShapeNet (about 51,300 models) and Princeton ModelNet (127,915 models). For the medical domain, we present a large collection of anatomical shapes (e.g., bones, organs, vessels) and 3D models of surgical instrument, called MedShapeNet, created to facilitate the translation of data-driven vision algorithms to medical applications and to adapt SOTA vision algorithms to medical problems. As a unique feature, we directly model the majority of shapes on the imaging data of real patients. As of today, MedShapeNet includes 23 dataset with more than 100,000 shapes that are paired with annotations (ground truth). Our data is freely accessible via a web interface and a Python application programming interface (API) and can be used for discriminative, reconstructive, and variational benchmarks as well as various applications in virtual, augmented, or mixed reality, and 3D printing. Exemplary, we present use cases in the fields of classification of brain tumors, facial and skull reconstructions, multi-class anatomy completion, education, and 3D printing. In future, we will extend the data and improve the interfaces. The project pages are: https://medshapenet.ikim.nrw/ and https://github.com/Jianningli/medshapenet-feedbac