Computed tomography and radiography in the diagnosis and followup of periprosthetic osteolysis after total ankle arthroplasty

Periprosthetic osteolysis is one of the most significant long-term complications after total ankle arthroplasty (TAA). The exact pathogenesis of osteolysis is unclear. It is a biological process involving many factors, mechanical factors probably, as well. Osteolysis is a progressive phenomenon which may lead to component failure. Traditionally, patients with an ankle prosthesis are monitored only by radiography. In this study the incidence of periprosthetic osteolysis around TAAs was evaluated by radiographs and computed tomography (CT). These two methods were also compared for detection of osteolytic lesions around the prosthesis components. Acquisition parameters and positioning were studied for optimal imaging of total ankle prostheses on CT. TAAs were monitored by CT after bone grafting of osteolytic lesions and also the patients’ symptoms after bone grafting were evaluated. Early-onset TAA-associated periprosthetic osteolysis was common after arthroplasty. CT showed more and larger periprosthetic osteolytic lesions than radiographs around TAAs, especially around the talar component. CT proved to be a reliable imaging modality for studying periprosthetic lesions adjacent to ankle prostheses. Image artifacts on CT caused by the metal prosthesis components were small when acquisition parameters and, especially, orientation of the prosthesis in relation to the x-ray tube were optimal. Radiologically, progression of osteolysis continued in spite of bone grafting of periprosthetic osteolytic lesions around TAAs. We recommend adding ankle CT to the postoperative follow-up for patients with suspected or known periprosthetic osteolytic lesions on radiographs. CT is also useful when evaluating periprosthetic bone stock before a reoperation.Nilkan tekoniveleen liittyvän osteolyysin diagnostiikka ja seuranta tietokonetomografia- ja rtg-kuvauksella Tekonivelen ympärille ilmaantuva osteolyysi on merkittävimpiä nilkan tekonivelleikkauksen myöhäisvaiheen komplikaatioita. Osteolyysin patogeneesiä ei täysin tunneta. Se on monitekijäinen biologinen prosessi, johon myös mekaaniset tekijät vaikuttavat. Osteolyysi on etenevä prosessi, joka pahimmillaan johtaa tekonivelen irtoamiseen. Potilaita, joilla on nilkan tekonivel, on perinteisesti kuvannettu ainoastaan natiiviröntgenkuvilla. Tässä tutkimuksessa nilkan tekonivelen ympärillä esiintyvää osteolyysiä tutkittiin röntgen- ja tietokonetomografiakuvauksella (TT); näitä kuvantamismenetelmiä myös verrattiin toisiinsa osteolyysimuutosten havaitsemisessa. Sen lisäksi etsittiin optimaalisia kuvausparametreja ja -asentoa ajatellen nilkan tekonivelen TT-kuvausta. Nilkan tekoniveliä seurattiin TT-kuvauksella osteolyysimuutosten luusiirretäytön jälkeen. Lisäksi potilaiden kliinisiä oireita tarkasteltiin näiden uusintaleikkausten jälkeen. Nilkan tekonivelten ympärillä havaittiin runsaasti osteolyysiä jo varsin varhaisessa vaiheessa tekonivelleikkauksen jälkeen. TT-kuvaus havaitsi enemmän ja kookkaampia muutoksia kuin röntgenkuvaus. Erityisesti telaluussa olevien osteolyysimuutosten arvioinnissa TT-kuvaus osoittautui hyödylliseksi kuvantamismenetelmäksi. TT-kuvaus oli luotettava kuvattaessa tekonivelen ympärillä olevia osteolyysimuutoksia. Metalliosien aiheuttamat artefaktat TT-kuvissa jäivät vähäisiksi, kun kuvausparametrit ja erityisesti tekonivelen asento suhteessa kuvausputkeen olivat optimaaliset. Osteolyysimuutosten luusiirretäytön jälkeen osteolyysin radiologinen progressio oli tavallista. Nilkan tekonivelen TT-kuvaus on suositeltavaa potilaille, joiden röntgenkuvissa on todettu tai epäilty osteolyysiä tekonivelen ympärillä. TT-kuvaus on myös hyödyllinen arvioitaessa luurakennetta tekonivelen ympärillä ennen uusintaleikkausta.Siirretty Doriast

Stationary intraoral digital tomosynthesis using a carbon nanotube X-ray source array

Intraoral dental tomosynthesis and closely related tuned-aperture CT (TACT) are low-dose three-dimensional (3D) imaging modalities that have shown improved detection of multiple dental diseases. Clinical interest in implementing these technologies waned owing to their time-consuming nature. Recently developed carbon nanotube (CNT) X-ray sources allow rapid multi-image acquisition without mechanical motion, making tomosynthesis a clinically viable technique. The objective of this investigation was to evaluate the feasibility of and produce high-quality images from a digital tomosynthesis system employing CNT X-ray technology

Quantitative Analysis of Three-Dimensional Cone-Beam Computed Tomography Using Image Quality Phantoms

In the clinical setting, weight-bearing static 2D radiographic imaging and supine 3D radiographic imaging modalities are used to evaluate radiographic changes such as, joint space narrowing, subchondral sclerosis, and osteophyte formation. These respective imaging modalities cannot distinguish between tissues with similar densities (2D imaging), and do not accurately represent functional joint loading (supine 3D imaging). Recent advances in cone-beam CT (CBCT) have allowed for scanner designs that can obtain weight-bearing 3D volumetric scans. The purpose of this thesis was to analyze, design, and implement advanced imaging techniques to quantify image quality parameters of reconstructed image volumes generated by a commercially-available CBCT scanner, and a novel ceiling-mounted CBCT scanner. In addition, imperfections during rotation of the novel ceiling-mounted CBCT scanner were characterized using a 3D printed calibration object with a modification to the single marker bead method, and prospective geometric calibration matrices

AUGMENTED REALITY AND INTRAOPERATIVE C-ARM CONE-BEAM COMPUTED TOMOGRAPHY FOR IMAGE-GUIDED ROBOTIC SURGERY

Minimally-invasive robotic-assisted surgery is a rapidly-growing alternative to traditionally open and laparoscopic procedures; nevertheless, challenges remain. Standard of care derives surgical strategies from preoperative volumetric data (i.e., computed tomography (CT) and magnetic resonance (MR) images) that benefit from the ability of multiple modalities to delineate different anatomical boundaries. However, preoperative images may not reflect a possibly highly deformed perioperative setup or intraoperative deformation. Additionally, in current clinical practice, the correspondence of preoperative plans to the surgical scene is conducted as a mental exercise; thus, the accuracy of this practice is highly dependent on the surgeon’s experience and therefore subject to inconsistencies. In order to address these fundamental limitations in minimally-invasive robotic surgery, this dissertation combines a high-end robotic C-arm imaging system and a modern robotic surgical platform as an integrated intraoperative image-guided system. We performed deformable registration of preoperative plans to a perioperative cone-beam computed tomography (CBCT), acquired after the patient is positioned for intervention. From the registered surgical plans, we overlaid critical information onto the primary intraoperative visual source, the robotic endoscope, by using augmented reality. Guidance afforded by this system not only uses augmented reality to fuse virtual medical information, but also provides tool localization and other dynamic intraoperative updated behavior in order to present enhanced depth feedback and information to the surgeon. These techniques in guided robotic surgery required a streamlined approach to creating intuitive and effective human-machine interferences, especially in visualization. Our software design principles create an inherently information-driven modular architecture incorporating robotics and intraoperative imaging through augmented reality. The system's performance is evaluated using phantoms and preclinical in-vivo experiments for multiple applications, including transoral robotic surgery, robot-assisted thoracic interventions, and cocheostomy for cochlear implantation. The resulting functionality, proposed architecture, and implemented methodologies can be further generalized to other C-arm-based image guidance for additional extensions in robotic surgery

1st EFORT European Consensus: Medical & Scientific Research Requirements for the Clinical Introduction of Artificial Joint Arthroplasty Devices

Innovations in Orthopaedics and Traumatology have contributed to the achievement of a high-quality level of care in musculoskeletal disorders and injuries over the past decades. The applications of new implants as well as diagnostic and therapeutic techniques in addition to implementation of clinical research, have significantly improved patient outcomes, reduced complication rates and length of hospital stay in many areas. However, the regulatory framework is extensive, and there is a lack of understanding and clarity in daily practice what the meaning of clinical & pre‐clinical evidence as required by the MDR is. Thus, understanding and clarity are of utmost importance for introduction of new implants and implant-related instrumentation in combination with surgical technique to ensure a safe use of implants and treatment of patients. Therefore EFORT launched IPSI, The Implant and Patient Safety Initiative, which starting from an inaugural workshop in 2021 issued a set of recommendations, notably through a subsequent Delphi Process involving the National Member Societies of EFORT, European Specialty Societies as well as International Experts. These recommendations provide surgeons, researchers, implant manufacturers as well as patients and health authorities with a consensus of the development, implementation, and dissemination of innovation in the field of arthroplasty. The intended key outcomes of this 1st EFORT European Consensus on “Medical & Scientific Research Requirements for the Clinical Introduction of Artificial Joint Arthroplasty Devices”are consented, practical pathways to maintain innovation and optimisation of orthopaedic products and workflows within the boundaries of MDR 2017/745. Open Access practical guidelines based on adequate, state of the art pre-clinical and clinical evaluation methodologies for the introduction of joint replacements and implant-related instrumentation shall provide hands-on orientation for orthopaedic surgeons, research institutes and laboratories, orthopaedic device manufacturers, Notified Bodies but also for National Institutes and authorities, patient representatives and further stakeholders. We would like to acknowledge and thank the Scientific Committee members, all International Expert Delegates, the Delegates from European National & Specialty Societies and the Editorial Team for their outstanding contributions and support during this EFORT European Consensus