ABSTRACT 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.

BACKGROUND:Infected non-union represents a severe complication after femoral shaft fractures, often associated with high recurrence rates and the need for multiple surgical revisions. Antimicrobial implant coatings may improve treatment success; however, evidence on the use of silver as an implant coating remains limited. This study aimed to (1) report short-term outcomes following treatment of infected femoral shaft non-union and (2) investigate if silver-polysiloxane-coating of implants leads to a significantly higher rate of treatment success at one-year follow-up. METHODS:This prospective cohort study (REFECT) with a historical control group included 70 patients treated for infected femoral shaft non-unions from 2013 to 2024 using either conventional, uncoated (UC, n = 62) or silver-polysiloxan-coated (SC, n = 8) implants with minimum of one-year follow-up. The primary outcome was successful treatment at one-year follow-up, defined as bony consolidation, and full weight-bearing and without recurrent infection. Secondary outcomes included clinical outcomes, blood serum analysis (including silver-ion concentration), radiographic outcomes, and patient reported outcome measures (SC-cohort only) including Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), Lower Extremity Functional Scale (LEFS), and EuroQol-Visual Analogue Scale (EQ-VAS). RESULTS:Mean follow-up was 43.9±33.1 months (SC: median (interquartile range), age 39 (27-62); UC: 52 (41-57); 25% female; 40% multidrug-resistant bacteria). The treatment success rate was significantly higher in the SC-cohort at one-year follow-up (SC: 100%, 95% CI 63-100% vs. UC: 61%, 95% CI 48-73%; p = 0.028). The SC-cohort showed a non-significant reduction of length of stay (p = 0.165) and number of operations (p = 0.182), while treatment costs were significantly lower (33886 € vs. 48937 €, p = 0.048). Compared to the preoperative state, the SC-cohort demonstrated improvement in WOMAC (p = 0.183), LEFS (p = 0.097), and EQ-VAS (p < 0.001). Serum silver ion concentration reached maximum 0.014 mg/l without clinical signs of argyria, and all SC-cohort patients had a reduction to normal concentration thresholds at final follow-up. CONCLUSIONS:This study presents short-term outcomes following treatment of patients with infected femoral shaft non-unions. Application of a silver-polysiloxane implant coating was associated with a significantly higher rate of treatment success at one-year-follow-up compared to conventional, uncoated implants. LEVEL OF EVIDENCE:Prospective Cohort Study with Historical Control Group, III.

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.de ORCID ID: https://orcid.org/0000-0002-4927-549X

Minimally invasive stabilization of acetabular and pelvic ring fractures using endoscopic techniques has become increasingly important. The logical advancement of conventional endoscopic techniques is a robot-assisted approach, which benefits from the advantages of robot-assistance systems (e.g., more degrees of freedom for instruments and improved visualization). The aim was therefore to investigate the feasibility of a robot-assisted endoscopic technique for plate osteosyntheses of the acetabulum and anterior pelvic ring. In this two-part feasibility study, four different plate osteosyntheses were performed endoscopically using the Hugo™ robot-assisted surgery system, first on ten synthetic pelvic models and then on ten human cadavers. During robot-assisted dissection for the preperitoneal approach, identification of ten relevant anatomical landmarks was also assessed. In both parts, the success, number of drilling errors, and time for each plate were described as learning curves and analyzed using linear regression. The infrapectineal plate could be successfully performed in 100

Background It is known that fractures of the pelvic ring and acetabulum in work-related accidents are associated with long periods of incapacity to work, a high rate of reduction in earning capacity (MdE) and high costs for pension/severance pay. Objective Investigation of changes in pension claims and costs from 2013 to 2019 after isolated fractures of the pelvic ring and acetabulum in work-related accidents in Germany. Material and methods For all patients from the German Social Accident Insurance (DGUV) registry with isolated fractures of the pelvic ring or acetabulum in work-related accidents, linear trend analyses were carried out among others for the proportion of MdE >= 20%, the proportion of cases receiving pension/severance pay and total costs for pension/severance pay from 2013 to 2019. A logistic regression analysis for the likelihood of receiving a pension was also performed. Results The proportion of MdE >= 20% decreased for fractures of the pelvic ring and acetabulum in total from 14.3% for 2013 to 8.2% for 2019 and there was a decreasing trend for the proportion of cases receiving pension/severance pay for fractures of the pelvic ring and acetabulum in total from 23.1% for 2013 to 13.6% for 2019 as well as for both fracture types individually. There was also a decrease in the costs for pensions/severance pay for fractures of the pelvic ring and acetabulum in total from 1,542,531 for 2013 to 1,006,887 for 2019. The likelihood of receiving a pension decreased by 8% per subsequent accident year between 2013 and 2019. Conclusion The proportion of pension claims and thus the costs for pensions/severance pay decreased for isolated fractures of the pelvic ring and acetabulum in work-related accidents from 2013 to 2019. The DGUV seems to fulfil its guideline Rehabilitation before pension.

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.

IntroductionBiomechanical studies have proved that locking plates have better primary stability besides versatility regarding fracture pattern while reducing bone contact and bridging the gap, whereas conventional nonlocking plates (plus lag screw) depend on bone-plate compression. The clinical benefit of locking plates over nonlocking plates remains unanswered, however. Therefore, this retrospective cohort study was set up to test the hypothesis that the use of locking plates for unstable ankle fractures will result in fewer re-displacements, superior bony healing, and functional and clinical outcomes better than observed in the nonlocking cohort.MethodsBimalleolar ankle fractures (AO 44-B2) without syndesmotic injury treated with either a locking or a nonlocking plate were included. Groups were compared for complications, bone healing, secondary dislocation, progressions of osteoarthritis, and clinical outcome using patient-reported outcome measures.ResultsData revealed no clinical outcome differences (Olerud-Molander Ankle Score: nonlocking 88.2 ± 14.4, locking 88.8 ± 12.3, P = .69, robust two 1-sided test for equality (RTOST): P = .03; American Orthopaedic Foot and Ankle Score: nonlocking 91.2 ± 12.9, locking 91.8 ± 11.3, P = .96, RTOST: P = .04). Nevertheless, a significant postoperative progression of osteoarthritis was detected in both groups (P = .04). This was independent of implant (P = .16). Although difference was not significant, locking plates were preferred in older (P = .78) and sicker patients (P = .63) and in cases with severer osteoarthritis (P = .16), and were associated with a higher complication rate (P = .42) and secondary dislocation (nonlocking 9.4%, locking 18.2%; P = .42). Re-displacement, however, was not a compelling reason for revision.ConclusionsThe present study shows statistically significant equality of both types of implants. Contrary to our expectation, locking plates seemed to be associated with a higher risk for re-displacement. Overall, the use of either locking or nonlocking plates for unstable AO 44-B2 fractures is safe and successful despite significant progression of osteoarthritis.Level of Evidence:III, Retrospective observational cohort study.

BACKGROUND:Extensive defects in long bones, resulting from trauma, disease, or other etiologies, impose significant morbidity on patients and may necessitate amputation, long-term disability, or premature mortality. While three-dimensional (3D)-printed, patient-specific implants offer promising regenerative solutions, their clinical implementation remains hindered by regulatory challenges, lack of standardized guidelines, and gaps in translational research. Addressing these barriers is critical to improving patient outcomes and optimizing healthcare resource utilization. MATERIALS AND METHODS:A multidisciplinary group of 29 experts - including clinicians (surgeons, anesthesiologists), biomaterial scientists, biomedical engineers, legal/regulatory professionals, health economists, meta-researchers, artificial intelligence experts, trialists, and biomaterial industry representatives - convened for the Consensus Meeting on 3D-printed patient-specific Bone Implants (CoMBI). Preceding the meeting, key questions were discussed in individual interviews and categorized into fundamental research, preclinical studies, and clinical trials and implementation (CoMBI themes). Experts presented on each theme, followed by structured discussions. Statements were synthesized, iteratively refined, and validated through open review. RESULTS:The consensus meeting resulted in 20 key statements addressing the CoMBI themes, outlining a framework to advance regulatory compliance and facilitate the clinical adoption of 3D-printed implants. Key statements include the need for harmonized regulatory pathways, clear guidelines on preclinical validation, and innovative trial designs tailored to complex, patient-specific implants. Strengthening collaboration among policymakers, regulatory agencies, and clinicians is crucial to overcoming current implementation barriers and ensuring equitable patient access to these advanced technologies. CONCLUSION:This Consensus Statement presents 20 key statements across fundamental research, preclinical studies, and clinical trials and implementation, offering a roadmap for accelerating the regulatory and clinical translation of 3D-printed patient-specific bone implants. The findings emphasize the critical role of interdisciplinary collaboration in overcoming challenges, such as standardizing implant development and navigating complex regulatory landscapes. By addressing these barriers and outlining practical strategies, the consensus highlights actionable steps to bridge the gap between innovation and clinical application.

(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.

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.

INTRODUCTION:Dual plating for distal femoral fractures, especially with a metaphyseal comminution, is biomechanically superior compared to single lateral plating, promotes fracture union and prevents complications. However, the optimal placement and length of the additional medial plate are still unknown. Thus, we aimed to biomechanically compare three different double plate constructs for distal femoral fractures. MATERIALS AND METHODS:A distal femoral fracture with a metaphyseal comminution (AO/OTA 33-A3) was created in synthetic femora and stabilized according to the following groups of 6 specimens each: Single lateral plate (SP), double plate with anteromedial oblique locking plate (DPOB), double plate with parallel medial locking plate with 4 screws (DP4S) and double plate with parallel medial locking plate with 6 screws (DP6S). Afterwards, the femora were tested axially with a quasi-static load of 400 N as well as torsionally with 5 Nm of internal and external rotation. Interfragmentary motion and rotation were measured with an optical 3D motion analysis system. RESULTS:Fracture gap motion and varus-valgus tilt under axial testing were significantly lower with DPOB, DP4S and DP6S than with SP (p = 0.02) without a significant difference between the double plate constructs. DP4S and DP6S showed a significant lower anteroposterior tilt under axial loading than SP (p = 0.02), whereas DPOB showed no significant difference compared to SP but had a significantly higher anteroposterior tilt than DP6S (p = 0.02). Under internal and external rotation testing, anteroposterior shift was significantly different, and axial rotation was significantly lower with DPOB, DP4S and DP6S compared to SP (p = 0.02) without a significant difference between the double plates. CONCLUSION:Dual plating is biomechanically superior under axial and torsional loading compared to the traditional single lateral plating for distal femoral fractures with metaphyseal comminution. A parallel arrangement of double plates is biomechanically more effective in resisting anteroposterior tilt, whereas the length of parallel medial plates (with 4 or 6 screws) has no influence on the biomechanical performance.

AimAim of this study was to establish the first clinical results after implantation of ultrathin silver-polysiloxane-coated1 plates in the treatment of infected non-union of the femoral shaft.MethodAs part of the REFECT study, a prospective, non-interventional analysis was conducted encompassing all patients who received internal stabilization with a silver-coated1 plate from 01/2023 to 09/2024 as part of the treatment for infected non-union of the femur. Standardized clinical follow-ups including PROMs (WOMAC-Index, LEF-S, EQ-5D, VAS) and X-rays were performed 3, 6, 12 (and 24) months postoperatively.For comparison, a retrospective analysis of 76 patients with infected femoral non-union, who had received a stabilization with an uncoated plate in the past 10 years, was performed.ResultsThe mean follow-up of the 8 included patients (mean bone defect: 3.6 cm) was 9 months (as of 04/24). Multiresistant bacteria were found in the intraoperative samples of 5 patients. The concentration of silver ions in blood serum reached a maximum of 0.014 mg/l in the laboratory controls. All patients showed a positive healing process with no sign of re-infection and no adverse procedure-associated events. Full weight bearing was achieved after an average of 4 months (n=6) with improved WOMAC-, LEF-S-, EQ-5D and VAS-score at 1-year FU. In the reference group (uncoated, mean FU: 3.5 years), there was a re-infection rate of 25 %, mostly in the first 2 years. Difficult-to-treat bacteria were detected in 22%, multiresistant Staph. epidermidis in 28% of cases.ConclusionsThe silver-coated1 implants showed good biocompatibility with no evidence of procedure-associated complications.The use of silver-coated1 implants could reduce the risk of re-infection.Further clinical data with longer follow-up are needed to assess the long-term value of the procedure.

Hexapod fixators are a specialized type of external fixators, which are used in the treatment of complex bone fractures. A set of metallic rings, which are attached to the bone fragments using wires and which are connected to each other by six length-adjustable struts, so-called distractors, enables a flexible and precise repositioning of fractures in six degrees of freedom. The lengths of the distractors define the configuration of the hexapod fixator and typically have to be iteratively adjusted over a period of several weeks. However, since the distractors are hard to reach for the patients, the length control is error-prone, limits the patient's autonomy and can even require prolonged hospitalization. To overcome these limitations, a new system for automatically measuring the distractor lengths is proposed, which utilizes optical proximity sensors and wirelessly transmits the results to a reader device. The system achieves a measurement accuracy of less than 1 mm over the full measurement range of 105 mm. It can be powered autonomously from a small button cell for several weeks. With dimensions of 24 mm x 10 mm, the electronics module adds only little volume and weight.

Background: Short-stem total hip arthroplasty (THA) has gained popularity due to its bone-sparing technique, but its outcomes in patients with obesity remain uncertain. The aim of this study was to investigate the impact of obesity on postoperative subsidence and clinical outcomes after short-stem THA. Methods: A retrospective cohort study with a minimum follow-up of 24 months was conducted on 163 patients who underwent short-stem THA with a collarless, triple-tapered, cementless stem achieving fixation in the metaphyseal region. Patients were categorized into obesity (Body Mass Index, BMI ≥ 30 kg/m2) and nonobesity (BMI < 30 kg/m2) groups. Subsidence rates, clinical outcomes, and complications were analyzed to assess the influence of BMI on the outcome of short stem THA. Regression analysis was performed to assess the influence of the independent variables (BMI, stem size, deviation from planning) on subsidence. Results: The obesity group (mean follow-up 58.6 months) exhibited significantly greater subsidence rates than did the nonobesity group (mean follow-up 38.9 months; 2.6 mm vs. 2.2 mm, p = 0.015). After removal of outliers, regression analysis revealed no linear relationship between BMI and subsidence (p = 0.35), but planned stem size was significantly correlated with subsidence (p = 0.005). Moreover, patients with obesity and larger planned stem sizes experienced greater subsidence. Clinical outcomes improved significantly in both groups. Conclusions: Obesity is associated with increased subsidence in short-stem THA, particularly in patients with larger planned stem sizes. Although BMI alone may not predict subsidence, careful selection of stem size and precise imaging techniques are crucial for minimizing subsidence risk in patients with obesity.

Methodology: In a consecutive retrospective analysis of 190 patients treated with the Masquelet technique at the BG Klinikum Hamburg from January 2012 to January 2022, subgroup analysis for defect-specific features such as the extent and morphology of the defect were recorded, and their influence on the time to reach full weight-bearing of the affected limb was investigated. Results and conclusion: A total of 217 defects were treated in 190 patients using the Masquelet technique. 70 % of all defects were in the tibia, followed by 22 % in the femur and only about 7 % in the upper extremity. The average length of all defects was 58 mm (+/- 31 mm), with the largest defect measuring 180 mm and the smallest measuring 20 mm. 89 % of the patients achieved full weight-bearing at the end of therapy. The average time from initiation of therapy to reaching safe full weight-bearing was 589 days. There was a significant correlation between defect length and time to reach full weight-bearing (p = 0.0134). These results could serve as a basis for creating a score for prognostics and evaluation of bone healing after treatment with the Masquelet technique. Additionally, the results could help guide indications for secondary stabilization using internal fixation.

Complex fractures of the trochanteric region, as well as fractures located in the directly subtrochanteric region, are controversially discussed around the world regarding the nail type to be used. A long nail is recommended by manufacturers but requires longer surgical and fluoroscopy times. A possible solution could be a nail with an appropriate length which can be locked in a minimally invasive manner by the main aiming device. We aimed to determine if such a nail model (DCN SL nail, SWEMAC, Linköping, Sweden) offers similar structural stability on biomechanical testing on artificial bone as a standard long nail when used to treat complex trochanteric fractures and compared it to long nails usually used in this setting. An osteoporotic bone model was chosen. The Swemac Hansson DCN Nail System was used as osteosynthesis material. Two types of nails were chosen: a superior lock nail which can be implanted with a singular targeting device, and a long nail with distal locking using free-hand technique. AO31A2.2 fractures were simulated in a standardised manner. Axial height of the construct, varus collapse, and rotational deformity directly after nail insertion were simulated. A Universal Testing Machine was used. Measurements were made with a stereo-optic tracking system. There was a detectable difference in the axial fracture movement resulting in narrowing of the fracture gap. There was no difference in varus collapse or rotational deformity between the nail variants We conclude that there are small differences which are clinically insignificant and that a superior locking nail can safely be used to manage complex trochanteric fractures.

Bekannt ist, dass Beckenring- und Acetabulumfrakturen im Rahmen von Arbeitsunfällen neben langen Arbeitsunfähigkeitszeiten auch mit einer hohen Rate an Minderungen der Erwerbsfähigkeit (MdE) sowie mit hohen Kosten für Renten/Abfindungen einhergehen. Untersuchung von Änderungen der Rentenleistungen von 2013 bis 2019 nach isolierten Beckenring- und Acetabulumfrakturen im Rahmen von Arbeitsunfällen in Deutschland. Für alle Patienten aus dem Register der Deutschen Gesetzlichen Unfallversicherung (DGUV) mit isolierter Beckenring- oder Acetabulumfraktur im Rahmen eines Arbeitsunfalls wurden lineare Trendanalysen u. a. für den Anteil an MdE ≥20

IntroductionA long nail is often recommended for treatment of complex trochanteric fractures but requires longer surgical and fluoroscopy times. A possible solution could be a nail with an appropriate length which can be locked in a minimally invasive manner by the main aiming device. We aimed to determine if such a nail model* offers similar structural stability on biomechanical testing on artificial bone as a standard long nail when used to treat complex trochanteric fractures.MethodAn artificial osteoporotic bone model was chosen. As osteosynthesis material two cephalomedullary nails (CMN) were chosen: a superior locking nail (SL-Nail) which can be implanted with a singular targeting device, and a long nail (long-nail) with distal locking using free-hand technique. AO31-A2.2 fractures were simulated in a standardized manner. The insertion of the nail was strictly in accordance with the IFU and surgical manual of the manufacturer. The nail was locked dynamically proximally and statically distally. Axial height of the construct, varus collapse, and rotational deformity directly after nail insertion were simulated. A Universal Testing Machine was used. Measurements were made with a stereo-optic tracking system. Reactive movements were recorded and evaluated in all six degrees of freedom. A comparative analysis provided information about the stability and deformation of the assemblies to be compared.ResultThere was a detectable difference in the axial fracture movement resulting in narrowing of the fracture gap. The load displacement was 1.7mm higher for the SL-Nail. There was no difference in varus collapse or rotational deformity between the nail variants.ConclusionWe conclude that there are small differences which are clinically insignificant and that a superior locking nail can safely be used to manage complex trochanteric fractures.*DCN SL nail, SWEMAC, Linköping, SwedenFunding: no funding