Changes in limb volume and shape among transtibial amputees affects socket fit and comfort. The ability to accurately measure residual limb volume and shape and relate it to comfort could contribute to advances in socket design and overall care. This work designed and validated a novel 3D laser scanner that measures the volume and shape of residual limbs. The system was designed to provide accurate and repeatable scans, minimize scan duration, and account for limb motion during scans. The scanner was first validated using a cylindrical body with a known shape. Mean volumetric errors of 0.17% were found under static conditions, corresponding to a radial spatial resolution of 0.1 mm. Limb scans were also performed on a transtibial amputee and yielded a standard deviation of 8.1 ml (0.7%) across five scans, and a 46 ml (4%) change in limb volume when the socket was doffed after 15 minutes of standing.

The introduction of the new generation of thumb carpometacarpal (CMC I) joint implants for the treatment of CMC I osteoarthritis has significantly broadened the scope of hand surgery in recent years. However, the technical demands of the procedure and the many details that need to be considered require appropriate training and a learning curve. To share experiences with the Touch CMC I prosthesis, we held the first German-speaking CMC I joint prosthetics user meeting in Zurich. After some basic introductory lectures on biomechanics and the principles of prosthetic fitting of the CMC I joint, the various challenges associated with CMC I joint prosthetics were discussed in interactive expert panels. Subsequently, cases were discussed in small groups under expert guidance and the respective conclusions were discussed in plenary. The main results of this symposium are summarised in this manuscript.
Durch die Einführung der neuesten Generation von Daumensattelgelenksprothesen zur Behandlung der Rhizarthrose hat sich das handchirurgische Behandlungsspektrum in den letzten Jahren deutlich erweitert. Der technische Anspruch dieser Operation und die vielen Details, die es zu beachten gilt, bedingen jedoch ein entsprechendes Training und eine damit verbundene Lernkurve. Um Erfahrungen mit der Touch Daumensattelgelenksprothese auszutauschen, haben wir das erste deutschsprachige Anwendertreffen zur Daumensattelgelenksprothetik in Zürich durchgeführt. Nach einigen grundlegenden Einführungsvorträgen zur Biomechanik und zu den Prinzipien der prothetischen Versorgung des Daumensattelgelenkes wurden in interaktiven Expertenrunden die verschiedenen Herausforderungen um die Daumensattelgelenksprothetik diskutiert. Anschließend wurden in Kleingruppen unter kundiger Leitung Fälle besprochen und die jeweiligen Konklusionen im Plenum diskutiert. Die wesentlichen Ergebnisse dieses Symposiums sind in diesem Manuskript zusammengefasst.

The use of in-situ audiometry for hearing aid fitting is appealing due to its reduced resource and equipment requirements compared to standard approaches employing conventional audiometry alongside real-ear measures. However, its validity has been a subject of debate, as previous studies noted differences between hearing thresholds measured using conventional and in-situ audiometry. The differences were particularly notable for open-fit hearing aids, attributed to low-frequency leakage caused by the vent. Here, in-situ audiometry was investigated for six receiver-in-canal hearing aids from different manufacturers through three experiments. In Experiment I, the hearing aid gain was measured to investigate whether corrections were implemented to the prescribed target gain. In Experiment II, the in-situ stimuli were recorded to investigate if corrections were directly incorporated to the delivered in-situ stimulus. Finally, in Experiment III, hearing thresholds using in-situ and conventional audiometry were measured with real patients wearing open-fit hearing aids. Results indicated that (1) the hearing aid gain remained unaffected when measured with in-situ or conventional audiometry for all open-fit measurements, (2) the in-situ stimuli were adjusted for up to 30 dB at frequencies below 1000 Hz for all open-fit hearing aids except one, which also recommends the use of closed domes for all in-situ measurements, and (3) the mean interparticipant threshold difference fell within 5 dB for frequencies between 250 and 6000 Hz. The results clearly indicated that modern measured in-situ thresholds align (within 5 dB) with conventional thresholds measured, indicating the potential of in-situ audiometry for remote hearing care.

BACKGROUND: In the process of transtibial prosthetic fitting, alignment is the process of positioning the prosthetic foot relative to the residual limb. Changes in frontal plane alignment can impact knee moments during walking, which can either cause or, when aligned properly, prevent injuries. However, clinical evaluation of dynamic knee moments is challenging, limiting prosthetists\' insights into dynamic joint loading. Typically, knee joint loading is assessed in static stance using the knee moment arm as a proxy for subsequent dynamic alignment. It remains uncertain if static alignment accurately represents actual dynamics during walking.
OBJECTIVE: Is the frontal knee moment arm in stance predictive for the knee moment arm and external knee adduction moment during gait in transtibial bone-anchored prosthesis users?
METHODS: In this cross-sectional study, twenty-seven unilateral transtibial bone-anchored prosthesis users underwent data acquisition on the M-Gait instrumented treadmill. Static and dynamic measurements were conducted, and knee moment arm and external knee adduction moment were calculated. Pearson\'s correlation and linear regression analyses were performed to examine relationships between static and dynamic knee moment arms and external knee adduction moments.
RESULTS: The static knee moment arm showed significant associations with dynamic knee moment arm at the ground reaction force peaks (First: r=0.60, r2=35%, p<0.001; Second: r=0.62, r2=38%, p=0.001) and knee adduction moment (First: r=0.42, r2=17%, p=0.030; Second: r=0.59, r2=35%, p=0.001). A 1 mm between-subject difference in static knee moment arm corresponded, on average, with a 0.9% difference in knee adduction moment at the first peak and a 1.5% difference at the second peak of the ground reaction force.
CONCLUSIONS: While static alignment is important to optimize adduction moments during stance it may only partly mitigate excessive moments during gait. The fair correlation and limited percentage of explained variance underscores the importance of dynamic alignment in optimizing the body\'s dynamic load during walking.

OBJECTIVE: This study aimed to evaluate the differences in electrically evoked compound action potential (ECAP) thresholds and postoperative mapping current (T) levels between electrode types after cochlear implantation, the correlation between ECAP thresholds and T levels, and the performance of machine learning techniques in predicting postoperative T levels.
METHODS: Retrospective case review.
METHODS: Tertiary hospital.
METHODS: We reviewed the charts of 124 ears of children with severe-to-profound hearing loss who had undergone cochlear implantation.
METHODS: We compared ECAP thresholds and T levels from different electrodes, calculated correlations between ECAP thresholds and T levels, and created five prediction models of T levels at switch-on and 6 months after surgery.
METHODS: The accuracy of prediction in postoperative mapping current (T) levels.
RESULTS: The ECAP thresholds of the slim modiolar electrodes were significantly lower than those of the straight electrodes on the apical side. However, there was no significant difference in the neural response telemetry thresholds between the two electrodes on the basal side. Lasso regression achieved the most accurate prediction of T levels at switch-on, and the random forest algorithm achieved the most accurate prediction of T levels 6 months after surgery in this dataset.
CONCLUSIONS: Machine learning techniques could be useful for accurately predicting postoperative T levels after cochlear implantation in children.

It is essential that people with limb amputation maintain proper prosthetic socket fit to prevent injury. Monitoring and adjusting socket fit, for example by removing the prosthesis to add prosthetic socks, is burdensome and can adversely affect users\' function and quality-of-life. This study presents results from take-home testing of a motor-driven adaptive socket that automatically adjusted socket size during walking. A socket fit metric was calculated from inductive sensor measurements of the distance between the elastomeric liner surrounding the residual limb and the socket\'s inner surface. A proportional-integral controller was implemented to adjust socket size. When tested on 12 participants with transtibial amputation, the controller was active a mean of 68% of the walking time. In general, participants who walked more than 20 min/day demonstrated greater activity, less doff time, and fewer manual socket size adjustments for the adaptive socket compared with a locked non-adjustable socket and a motor-driven socket that participants adjusted with a smartphone application. Nine of 12 participants reported that they would use a motor-driven adjustable socket if it were available as it would limit their socket fit issues. The size and weight of the adaptive socket were considered the most important variables to improve.

OBJECTIVE: Templating is the first step in achieving a successful total hip arthroplasty. We hypothesize that native head size is highly correlated with implanted cup size. Therefore, the purpose of this study is to look for a correlation between sizes of the intra-operative measurement of the femoral head and the implanted cup.
METHODS: This is a monocentric observational study conducted from December 2018 till January 2023. All patients admitted for a primary total hip arthroplasty were included and retrospectively reviewed. Intra-operative femoral head measurement, radiographic femoral head diameter, templated (planned) cup size, and definitive implanted cup size were recorded.
RESULTS: The sample included 154 patients (85 female and 69 males) with a mean age of 66.2 ± 10.4 years. There were 157 THA cases; 82 on the right side and 75 on the left side. The native head size and acetate template on digital radiographs were the most significantly positively correlated with cup size (P < 0.0001) while the radiological head size was significantly negatively correlated with cup size (P = 0.009). The implanted cup was on average 2 ± 2 mm bigger than the native head size measured intra-operatively.
CONCLUSIONS: The native femoral head diameter measured intra-operatively is a simple and reliable tool to help the surgeons choose the proper size of the acetabular cup, preventing complications during surgery hence optimizing results post operatively. This technique would contribute to a more ecofriendly orthopaedic reconstructive surgery.

The modern treatment strategy for keratoconus (KC) involves sequential application of medical technologies aimed at stabilizing pathological changes in the cornea and restoring visual acuity.
OBJECTIVE: This study compares the effect of implantation of intrastromal corneal ring segment (ICRS) and fitting of individual scleral rigid contact lenses (RCLs) on visual functions in patients with stage II-III KC after previously performed corneal collagen cross-linking.
METHODS: The Helmholtz National Medical Research Center of Eye Diseases examined and treated 34 patients (69 eyes) aged 18 to 33 years with stage II-III KC. The study included patients who had previously undergone standard corneal collagen cross-linking. Depending on the type of optical correction, the patients were divided into two groups: patients in group 1 underwent ICRS implantation using a femtosecond laser; patients in group 2 were fitted with individual scleral RCLs.
RESULTS: Improvement in clinical and functional parameters was observed in both groups. A higher clinical and functional result was achieved in group 2.
CONCLUSIONS: For patients with stable stage II-III KC, it is advisable to recommend fitting of individual scleral RCLs for visual rehabilitation.
Современная тактика лечения кератоконуса (КК) заключается в последовательном применении медицинских технологий, направленных на стабилизацию патологических изменений роговицы и восстановление остроты зрения.
UNASSIGNED: Сравнительный анализ влияния имплантации интрастромальных роговичных сегментов (ИРС) и подбора индивидуальных склеральных жестких контактных линз (ЖКЛ) на зрительные функции пациентов с КК II—III стадии после ранее проведенного кросслинкинга роговичного коллагена.
UNASSIGNED: В НМИЦ ГБ им. Гельмгольца обследовано и пролечено 34 пациента (69 глаз) в возрасте от 18 до 33 лет с КК II—III стадии. В исследование были включены пациенты с раннее проведенным кросслинкингом роговичного коллагена по стандартной методике. В зависимости от вида оптической коррекции пациенты были разделены на две группы: пациентам 1-й группы проведена имплантация ИРС с помощью фемтосекундного лазера; пациентам 2-й группы были подобраны индивидуальные склеральные ЖКЛ.
UNASSIGNED: В обеих группах отмечалось улучшение клинико-функциональных показателей. Во 2-й группе достигнут более высокий клинико-функциональный результат.
UNASSIGNED: Пациентам со стабильным КК II—III стадии с целью проведения зрительной реабилитации целесообразно рекомендовать подбор индивидуальных склеральных ЖКЛ.

OBJECTIVE: The fit and optical performance of a scleral lens is affected by the alignment of the landing zone with the underlying ocular surface. The aim of this research was to quantify the effect of landing zone toricity upon scleral lens fitting characteristics (rotation and decentration) and optics (lens flexure) during short-term wear.
METHODS: Scleral lenses with nominal landing zone toricities of 0, 100, 150 and 200 μm were worn in a randomised order by 10 young healthy participants (mean [SD] 24 [7] years) for 30 min, with other lens parameters held constant. Scleral toricity was quantified using a corneo-scleral profilometer, and lens flexure, rotation, and decentration were quantified using over-topography during lens wear. Repeated measures analyses were conducted as a function of landing zone toricity and residual scleral toricity (the difference between scleral and lens toricity) for eyes with \'low\' magnitude scleral toricity (mean: 96 μm) and \'high\' magnitude scleral toricity (mean: 319 μm).
RESULTS: Toric landing zones significantly reduced lens flexure (by 0.37 [0.21] D, p < 0.05) and lens rotation (by 20 [24]°, p < 0.05) compared with a spherical landing zone. Horizontal and vertical lens decentration did not vary significantly with landing zone toricity. These trends for flexure, rotation, and decentration were also observed for eyes with \'low\' and \'high\' magnitude scleral toricity as a function of residual scleral toricity.
CONCLUSIONS: Landing zones with 100-200 μm toricity significantly reduced lens flexure (by ~62%) and rotation (by ~77%) but not horizontal or vertical lens decentration, compared with a spherical landing zone, when controlling for other confounding variables. The incorporation of a toric landing zone, even for eyes with lower magnitude scleral toricity (~100 μm), may be beneficial, particularly for front surface optical designs.

OBJECTIVE: To explore the potential of artificial intelligence (AI) to assist prescription determination for orthokeratology (OK) lenses.
METHODS: Artificial intelligence algorithm development followed by a real-world trial. A total of 11,502 OK lenses fitting records collected from seven clinical environments covering major brands. Records were randomly divided in a three-way data split. Cross-validation was used to identify the most accurate algorithm, followed by an evaluation using an independent test data set. An online AI-assisted system was implemented and assessed in a real-world trial involving four junior and three senior clinicians.
RESULTS: The primary outcome measure was the algorithm\'s accuracy (ACC). The ACC of the best performance of algorithms to predict the targeted reduction amplitude, lens diameter, and alignment curve of the prescription was 0.80, 0.82, and 0.83, respectively. With the assistance of the AI system, the number of trials required to determine the final prescription significantly decreased for six of the seven participating clinicians (all P <0.01). This reduction was more significant among junior clinicians compared with consultants (0.76±0.60 vs. 0.32±0.60, P <0.001). Junior clinicians achieved clinical outcomes comparable to their seniors, as 93.96% (140/149) and 94.44% (119/126), respectively, of the eyes fitted achieved unaided visual acuity no worse than 0.8 ( P =0.864).
CONCLUSIONS: AI can improve prescription efficiency and reduce discrepancies in clinical outcomes among clinicians with differing levels of experience. Embedment of AI in practice should ultimately help lessen the medical burden and improve service quality for myopia boom emerging worldwide.