Arndt-Peter Schulz

Background: Considerable variation exists in the proximal and distal fixture designs used in biomechanical testing of diaphyseal femoral implants. In most of them a load is applied to the femoral head, but muscle forces are rarely represented, so bending of the diaphysis is unphysiologically high. Methods: This study investigated twelve testing configurations reported in the literature using finite element and analytical models of the femoral diaphysis and a lateral fixation plate. The models differed in proximal and distal displacement constraints, femoral orientation, and load application. Internal force distributions, as well as bone and implant stresses and bone strains, were calculated for each configuration. Results: Common experimental conditions, in which the load is applied to the femoral head, generally produced high bending moments, resulting in, what we interpret to be, unrealistically high bone and implant stresses and bone strains. In contrast, axial loading along the femoral shaft generated substantially lower bending, which we propose to be more physiological, particularly in two such cases with reduced rotational constraint. Conclusions: Their constant bending distribution should improve reproducibility and their implementation should provide a practical approach to biomechanical testing of diaphyseal femoral implants.

BACKGROUND: Early rehabilitation after transfemoral amputation aims to restore mobility, reduce compensatory strain, and improve quality of life. Powered prosthetic knees, such as the Össur Power Knee, may facilitate more physiological gait patterns in comparison to conventional prosthetic knees; however, evidence regarding their use during the initial rehabilitation phase remains limited. OBJECTIVE: To explore the safety and usability of the Össur Power Knee during rehabilitation following transfemoral amputation. METHODOLOGY: This prospective single-center exploratory study was conducted in a rehabilitation center of a public trauma hospital in Germany from October 1st 2023 until July 1st 2024 and included three adults with unilateral transfemoral amputation, who received the Össur Power Knee III (2021) as their initial prosthesis and completed standard interdisciplinary rehabilitation. Assessments were performed at baseline, 14 days, 1, 3 and 5 months. Outcomes were assessed in five domains: pain assessment, health-related quality of life, objective mobility and functional capacity, balance confidence and functional independence as well as prosthesis usability. Safety and adverse events were monitored throughout follow-up. RESULTS: Over five months, all three participants demonstrated improvements in EuroQol 5-Dimension 5-Level, Locomotor Capabilities Index, and Amputee Mobility Predictor scores, while two participants experienced reduced pain. Prosthesis usability scores varied across participants. Functional performance measures remained stable or improved across all cases. Two minor falls occurred that were unrelated to the device and did not result in injury. CONCLUSION: Early rehabilitation using the Össur Power Knee was feasible. During rehabilitation, patients reported reduced pain and improvements in mobility and patient-reported outcomes. However, these outcomes cannot be solely attributed to the Össur Power Knee, as interpretation is limited by the small sample size, single-arm design, and short follow-up period. Layman's Abstract After a transfemoral (above-knee) amputation, people need rehabilitation to regain walking ability and independence in everyday life. Powered prosthetic knee joints use a small motor to help bend and straighten the knee, making walking more natural. This study followed three people with a recent transfemoral amputation who received their first prosthesis with a powered knee joint between October 1, 2023, and January 31, 2024. Their rehabilitation progress was monitored over five months at a rehabilitation center within a public trauma hospital in Germany. Each participant was assessed before fitting and during follow-up visits using tests and questionnaires measuring pain, health, walking ability, balance, independence, and prosthesis usability. All three participants showed meaningful improvements over five months. Perceived pain decreased in two participants, while walking ability, daily function, balance confidence, and overall quality of life improved. Walking speed and endurance also generally increased. No serious device-related problems occurred. Two minor falls without injury were reported and were unrelated to the device. These findings suggest that using a powered knee during early rehabilitation is feasible and may support positive outcomes. However, due to the small number of participants, lack of a comparison group, and limited follow-up period, larger controlled studies are needed to confirm these findings. Article PDF Link: https://jps.library.utoronto.ca/index.php/cpoj/article/view/47124/35140 How To Cite: Schaeffer S, Bufe K, Kluge S, Blaschke M, Linnert N, Lechler K, et al. Clinical outcomes in early rehabilitation using the Össur Power Knee: An exploratory pilot study. Can Prosthet Orthot J. 2026;9(2):2. https://doi.org/10.33137/cpoj.v9i2.47124 Corresponding Author: Prof. Dr. Arndt P. Schulz,Affiliation: Department of Clinical Research, BG Klinikum Hamburg, Hamburg, Germany.E-Mail: schulz@biomechatronics.deORCID ID: https://orcid.org/0000-0002-4927-549X

Objective: Implant‐associated infections, including periprosthetic joint infection (PJI) and fracture‐related infection (FRI), are among the most challenging complications in orthopedic surgery. Although infection timing (early, delayed, late) is recognized as an important factor in surgical success, its impact on patient‐reported outcomes and length of hospital stay has rarely been compared between PJI and FRI in a single cohort. This study aimed to examine the association between infection timing and health‐related quality of life (HRQoL) as well as length of hospital stay (LOS), and to explore potential differences between PJI and FRI. Methods: We conducted a retrospective monocentric cohort study of 60 patients with microbiologically confirmed implant‐associated infections treated at a German level‐I trauma center between January and December 2021, with follow‐up performed in 2023. Patients with PJI ( n = 29) or FRI ( n = 31) were stratified as early (< 3 months), delayed (3–24 months), or late (> 24 months) to enable direct comparison between infection entities. Outcomes included EQ‐VAS, EQ‐5D‐3L mean domain scores, LOS, reinfection, revision surgery, amputation, and in‐hospital mortality. Group differences were tested using independent‐samples t‐tests for continuous variables and chi‐square or Fisher's exact tests for categorical variables, with subgroup analyses considered exploratory due to small sample sizes. Results: Of the 60 patients, 25 had early (PJI n = 11; FRI n = 14), 24 delayed (PJI n = 11; FRI n = 13), and 11 late infections (PJI n = 7; FRI n = 4). EQ‐VAS was higher in FRI compared with PJI in early (63.4 ± 17.8, n = 13 vs. 48.3 ± 20.8, n = 9) and delayed infections (66.2 ± 16.8, n = 11 vs. 56.6 ± 13.5, n = 10), while both groups showed markedly lower EQ‐VAS values in late infections (FRI: 39.7 ± 25.9, n = 3 vs. PJI: 43.3 ± 23.4, n = 6), which were analyzed descriptively due to very small subgroup sizes. The EQ‐5D‐3L mean domain score was lower (indicating better health status) in early FRI (1.55 ± 0.33, n = 12) than in early PJI (1.91 ± 0.39, n = 9) in unadjusted analyses. LOS increased with timing, particularly in PJI (early 39.6 ± 26.8 vs. 31.4 ± 29.0 days; delayed 100.6 ± 82.2 vs. 28.2 ± 10.2; p = 0.015). Reinfection rates increased with later timing (early: 6/11 PJI vs. 3/14 FRI; delayed: 8/11 vs. 8/13; late: 5/7 vs. 4/4). Revision surgery was more frequent in early PJI (7/11 vs. 4/14; p = 0.080) but was significantly more common in delayed FRI (12/13 vs. 6/11; p = 0.033). Amputation (≤ 9%) and in‐hospital mortality (≤ 15%) were rare and showed no significant differences. Conclusions: Infection timing was associated with both clinical and patient‐reported outcomes in implant‐associated infections. Later infections were associated with poorer HRQoL, longer hospital stays, and higher reinfection rates, based on unadjusted analyses, with distinct patterns between PJI and FRI. Early recognition and timely, stage‐adapted treatment strategies may help improve patient outcomes.

Minimally invasive stabilization of acetabular and pelvic ring fractures using endoscopic techniques has become increasingly important. The logical advance

(1) Aim: This study aims to assess the repeatability and accuracy of a 9-axis IMU-based glove and an IR camera system, in order to determine their potential to replace traditional goniometry. (2) Background: Traditional methods for assessing hand function, such as goniometry, are time-consuming and limited by subjectivity, inter-rater variability and external factors that compromise accuracy and reliability. Recent advancements in motion capture technology and sensor-based devices offer potential improvements in efficiency and accuracy for hand rehabilitation assessment; (3) Methods: To evaluate the repeatability of an IMU-based glove and an IR camera, measurements were taken using a silicone hand model under controlled conditions, while accuracy assessments involved a volunteer without movement constraints. Bland–Altman plots were employed for visual comparison and accuracy evaluation; (4) Results: The Nuada glove exhibited high repeatability, with standard deviations below two degrees across all joints, surpassing the goniometer’s accuracy threshold of five degrees. The UltraLeap system demonstrated comparable repeatability, with deviations consistently under 3.5 degrees. Accuracy assessments revealed limitations: over 50% of the Nuada glove’s measurements and over 80% of UltraLeap’s measurements deviated by more than five degrees compared to the goniometer. However, the Nuada glove and UltraLeap system were more consistent with each other than with the goniometer, suggesting limitations in the goniometer’s reliability for modern mobility assessment; (5) Conclusions: Both devices exhibited excellent repeatability, highlighting their strong potential for clinical application. However, their accuracy compared to the goniometer requires further refinement. These findings suggest that these technologies could enhance traditional assessment methods, offering more efficient and accurate solutions for evaluating hand mobility in clinical settings.

Objectives: The study aims on evaluation criteria applicable for the development process of new mobile 3D X-ray imaging devices, based on existent knowledge from literature and user expertise. Methods: For this purpose, a structured literature review was performed to outline limitations and opportunities of established systems on the market. Additionally, medical professionals from various medical fields were interviewed, following a structured interview protocol, to identify critical evaluation aspects from a user perspective. Results: The study identified a total of 52 evaluation criteria, which were categorized into the following domains: clinical application and manageability, image quality, radiation dose and risk of infection. The analysis of user needs, subsequent summarization, and rating of these needs will serve as a new benchmark for the evaluation of both existing and new devices. This will provide guidance to procurement, medical experts, and manufacturers. Conclusions: While the structured evaluation of mobile X-ray devices is possible, consultation of the users regarding their weighting of varying needs will remain an important aspect of the process. The evaluation items can serve as a starting point for this analysis.

Background: The aim of this study was to systematically explore point-of-care biomarkers as diagnostic indicators for the detection and exclusion of mild traumatic brain injury (mTBI) in an emergency room (ER) setting using Eye-Tracking and Virtual Reality (ET/VR) technology. The primary target group included patients who had suffered an acute trauma to the head and presented within 24 h to the emergency department. Methods: The BG Unfallkrankenhaus Berlin and the BG Klinikum Hamburg participated in this explorative, prospective, single-arm accuracy study. This study included patients who presented to the emergency department with suspected mTBI and were examined using ET/VR glasses. All further steps corresponded to clinical routine (e.g., decision on hospital admission, imaging diagnostics). After the completion of treatment, the patients were divided into mTBI and non-TBI subgroups by consensus between two independent clinical experts, who were blinded to the results of the index test (examination using ET/VR glasses) in the form of a clinical synopsis. The diagnosis was based on all clinical, neurological, neurofunctional, neuropsychological, and imaging findings. Routine trauma and neurological history, examination, and diagnosis were performed in each case. All statistical analyses were performed with exploratory intent. Results: The use of ET/VR glasses was found to be predominantly unproblematic. Two of the fifty-two analyzed parameters can be statistically distinguished from a random decision. No difference in oculomotor function was found between the two subgroups, and no correlations between the parameters recorded by the VR goggles and the detection of mTBI were found. Conclusions: At present, the use of VR goggles for the diagnosis of mTBI in an ER setting cannot be recommended.

A total of 66 smart implants were included. As a measure of bony stability, the relative elastic compliance of the osteosynthesis was determined from the gradient between the applied external load and the measured implant load over the entire healing process. The healing process of non-unions of the femur with a smart implant was tracked by telemetric measurements over a timespan of up to 10 years. The measurements of the longest healing process show a very slow but constant decrease in force transmission over the implant, radiological findings over 10 years show corresponding consolidation until bony healing. The use of a telemetrically instrumented bone plate, a so-called smart implant, to monitor the healing process is a successful procedure to support the clinician in his decision to take further surgical measures or to wait until healing occurs.