Journal of Orthopaedic Research®最新文献

Sufficient refixation and healing is crucial for the function of a reverse shoulder arthroplasty within the treatment of proximal humeral fractures. Conventional refixation with suture cerclage is time-consuming and leads to healing in only 60–70% of cases. This study used a biomechanical test to investigate two different refixation procedures for treating 4-fragment fractures of the proximal humerus. Eight paired humerus specimens were randomly assigned to two groups and treated with reverse shoulder prostheses. One group received conventional suture cerclage fixation for 4-fragment fractures, while the other used a novel TendoClip system with screw fixation. Both groups were subjected to increasing cyclic tensile forces until failure. Fragment movement relative to the prosthesis stem was measured to assess primary stability. Tensile forces generated in the first four load levels resulted in significantly different relative motions between the TendoClip and cerclage groups. 3 out of 8 specimens in the TendoClip group could be loaded over all load levels. This was not possible for any cerclage group specimens. Recorded failure mechanisms showed that fixed bone fragments of the cerclage procedure were affected significantly more often by loosening and visible relative movements compared to the TendoClip procedure. However, limitations of the TendoClip restoration were also observed. In 2 of 8 cases, a bone fragment was torn out of the fixation, and two other implants showed a loss of fixation in relation to the humerus. This study reveals that the TendoClip procedure could be an alternative to conventional cerclage fixation procedures in multifragmentary proximal humerus fractures.

Bone fractures are common injuries with reported non-union rates of up to 9%. Current treatments for non-union include surgery with complication rates of up to 17% and significant costs. Microbubbles are used clinically in ultrasonography as contrast agents and have been shown to deliver therapeutics to desired locations by noninvasive stimulation of cavitation using extracorporeal ultrasound in preclinical studies. Contrast enhanced ultrasound (CEUS) has been used to determine the cause of established fracture non-unions, though this is not in widespread use clinically. This pilot study aimed to test the hypothesis that peripherally injected microbubbles are detectable in acute fracture sites. Adult patients (18–75 yrs) with acute humeral shaft fractures were recruited to undergo CEUS within 28 days of injury. They underwent peripheral injection of SonoVue microbubbles with ultrasound imaging. B-mode and contrast-mode videos were collected and time-intensity curve analysis was used to assess for the presence of microbubbles at the fracture site. Ten patients were recruited, 8 underwent humeral shaft fracture scans with 7 analysed. All fracture sites demonstrated increased contrast signal following injection. The wash-in volume of microbubbles was greater than the wash-out volume in all cases, with a mean difference of 1.4 × 10⁻⁵ (± 1.7 × 10⁻⁵) (p = 0.015 Wilcoxon Test). There was a trend toward decreasing PI and TtP with fracture age, though not statistically significant (R² = 0.44, p = 0.1; R² = 0.24, p = 0.26, respectively). This pilot study demonstrates that commercially available microbubbles perfuse acute fractures in ultrasonographically detectable quantities using commercially available equipment.

Progression of medial knee osteoarthritis (OA) has been associated with walking biomechanics, specifically with the knee adduction (KAM) and flexion (KFM) moments. Lower medial stiffness shoes (LMSS), that are shoes with the sole made of softer material medially than laterally, were proposed for disease management through KAM reductions. This study primarily tested the hypothesis that larger pKAM reductions can be achieved with stiffness ratios selected individually than with the smallest ratios of the LMSS. Secondarily, the proportions of individuals reducing the KAM or reducing the KAM without increasing the KFM were compared between the individualized and smallest ratios conditions. The two LMSS conditions were also compared with lateral wedge insoles. Walking biomechanics were recorded for 15 OA patients (8 males; 62.3 ± 9.6 years old) and 14 asymptomatic individuals (5 males; 53.6 ± 3.6 years old) wearing LMSS with various stiffness ratios and wedges. Larger decreases in KAM were obtained with individualized stiffness ratios (14.0%–16.4%) than with the two other interventions (6.7%–12.5%) (p < 0.001). The percentage of participants reducing the KAM without increasing the KFM was larger with individualized ratios compared to the smallest ratios in the OA group (14 vs. 6; p = 0.001) and compared to wedges in the asymptomatic group (13 vs. 6; p = 0.015). This exploratory study showed the potential of individualizing the stiffness ratios, particularly in terms of KAM reduction amplitude, percentage of individuals achieving specific modifications, and possibility to aim for more complex kinetic changes. Further work is necessary to assess the effect of individualized stiffness ratios on clinical outcomes.

In uncemented hip arthroplasty, achieving sufficient primary stability is essential for long-term implant success. However, objective intraoperative assessment of fixation quality remains challenging. Acoustic analysis of stem impaction sounds offers a promising tool for real-time evaluation, but its diagnostic accuracy and biomechanical correlation require further validation. Twelve formalin-fixed human femora were implanted with cementless Metha short stems under three predefined anchorage conditions: loose, optimal (fit), and fracture-inducing press-fit. Impaction sounds were recorded using calibrated microphones and processed via frequency-domain analysis. Relative micromotions were quantified under torsional loading to biomechanically assess primary stability. Spectral markers reliably differentiated between anchorage states. The transition from loose to fit showed minimal spectral change, yet emerged as statistically significant across multiple frequency clusters, while fit-to-fracture was characterized by a significant increase in low-frequency energy (< 2.5 kHz) and pronounced attenuation in high-frequency bands (> 15 kHz). These acoustic signatures closely correlated with biomechanically measured micromotions, which showed a distinct hierarchy: fracture < fit < loose. Cluster permutation analysis confirmed statistically significant differences between all groups, particularly in the fracture condition. This in vitro study demonstrates that frequency-based acoustic analysis can distinguish between stable, insufficient, and over-press-fit conditions during stem implantation. The findings support the feasibility of intraoperative acoustic monitoring as a real-time, objective tool to enhance implant safety and detect cortical compromise at an early stage, before clinical manifestation. However, translation into a clinical product will require further algorithmic development, integration into a surgical interface, and prospective in vivo validation.

Articular cartilage undergoes structural and compositional changes during osteoarthritis (OA), one of the most common joint diseases. Earlier research shows that these changes are dependent on species and joint site, and they also vary across cartilage depth. In this study, we analyzed the depth-wise proteoglycan and collagen contents, as well as collagen fibril orientation angle and fibril alignment in human tibial and femoral cartilage at different severities of osteoarthritis. Samples were divided into normal cartilage, moderate OA cartilage, and severe OA cartilage based on OARSI grade. Consistent with earlier research, proteoglycan and collagen contents were generally lower in samples of greater OA severity, with the notable exception of a higher collagen content in femoral severe OA cartilage. Femoral severe OA cartilage had considerably lower proteoglycan content than femoral normal or moderate OA cartilage, and its collagen fibril orientation and anisotropy became more uniform throughout cartilage thickness. Qualitative analysis between tibial and femoral cartilage sites also revealed a gradual progressive structural and compositional degradation in tibial cartilage compared to femoral cartilage, in which the structure and composition remained relatively unchanged until the severe OA severity. With this depth-wise and site-specific compositional and structural information, our work elucidates disease progression in human cartilage.