Osteoblasts are mechanosensitive cells, which respond to biomechanical stimuli to regulate the bone structure through anabolic and catabolic gene regulation. To examine the effects of mechanical forces on the osteogenic responses through the SMAD sig

Background: Almost all epidemiological studies over the past 40 years have determined that the incidence of fragility fractures is increasing. Therefore, the assessment of postural stability and monitoring any progress during balance training for geriatric patients to prevent falls are becoming more important. The Nintendo^® Wii Fit Balance Board, with its integrated software and scoring system, might be a cheap and easily accessible tool for this purpose. Methods: This prospective study analyzed the diagnostic value of the Wii Fit Balance Board in 41 healthy subjects using two measurements: the yoga task “tree,” which is performed in one-leg stance; and the balance game “table tilt.” Our investigation compared these tasks to two established, regularly used systems, the MFT-S3 Check and the Posturomed, by looking for correlation and agreement, using Bland–Altman plots, as well as for differences to demographic data. All measurement tools were also compared to the Sensory Organization Test—the gold standard for detecting impaired balance. Results: We found a moderate correlation between the yoga exercise “tree” and the Sensory Organization Test (correlation coefficient r = 0.514, p = 0.001) as well as the MFT-S3 Check (r = 0.356–0.472, p = 0.002–0.022) and the Posturomed (r = 0.345, p = 0.027). However, results from the balance game “table tilt” did not show a significant correlation with those of the systems to which we compared it (p = 0.301–0.953). Conclusions: According to the literature, the raw data from the Wii Fit Balance Board are comparable to that obtained by laboratory-grade force platforms. We have found, however, that the yoga pose “tree,” as integrated into the Nintendo^® Wii Fit Balance Board with its own scoring system, also correlates with the gold-standard Sensory Organization Test. It also correlates with two frequently used diagnostic and therapeutic devices. We, therefore, conclude that the Wii Fit Balance Board is suitable for the evaluation of postural stability and may be useful in preventing falls among the geriatric population. Level of evidence: 2b.

Posttraumatic osteoarthritis constitutes a major cause of disability in our increasingly elderly population. Unfortunately, current imaging modalities are too insensitive to detect early degenerative changes of this disease. Optical coherence tomography (OCT) is a promising nondestructive imaging technique that allows surface and subsurface imaging of cartilage, at near-histological resolution, and is principally applicable in vivo during arthroscopy. Thirty-four macroscopically normal human cartilage-bone samples obtained from total joint replacements were subjected to standardized single impacts in vitro (range: 0.25J to 0.98J). 3D OCT measurements of impact area and adjacent tissue were performed prior to impaction, directly after impaction, and 1, 4, and 8 days later. OCT images were assessed qualitatively (DJD classification) and quantitatively using established parameters (OII, Optical Irregularity Index; OHI, Optical Homogeneity Index; OAI, Optical Attenuation Index) and compared to corresponding histological sections. While OAI and OHI scores were not significantly changed in response to low- or moderate-impact energies, high-impact energies significantly increased mean DJD grades (histology and OCT) and OII scores. In conclusion, OCT-based parameterization and quantification are able to reliably detect loss of cartilage surface integrity after high-energy traumatic insults and hold potential to be used for clinical screening of early osteoarthritis. Posttraumatic osteoarthritis constitutes a major cause of disability in our increasingly elderly population. Unfortunately, current imaging modalities are too insensitive to detect early degenerative changes of this disease. Optical coherence tomography (OCT) is a promising nondestructive imaging technique that allows surface and subsurface imaging of cartilage, at near-histological resolution, and is principally applicable in vivo during arthroscopy. Thirty-four macroscopically normal human cartilage-bone samples obtained from total joint replacements were subjected to standardized single impacts in vitro (range: 0.25J to 0.98J). 3D OCT measurements of impact area and adjacent tissue were performed prior to impaction, directly after impaction, and 1, 4, and 8 days later. OCT images were assessed qualitatively (DJD classification) and quantitatively using established parameters (OII, Optical Irregularity Index; OHI, Optical Homogeneity Index; OAI, Optical Attenuation Index) and compared to corresponding histological sections. While OAI and OHI scores were not significantly changed in response to low- or moderate-impact energies, high-impact energies significantly increased mean DJD grades (histology and OCT) and OII scores. In conclusion, OCT-based parameterization and quantification are able to reliably detect loss of cartilage surface integrity after high-energy traumatic insults and hold potential to be used for clinical screening of early osteoarthritis.

Eine Berücksichtigung der individuellen biomechanischen Verhältnisse im Hüftgelenk stellt einen großen Vorteil im Kontext der Planung einer Hüftgelenkstotalendoprothese dar und kann das Ergebnis des Eingriffs positiv beeinflussen. Zum jetzigen Zeitpunkt erfolgt die Operationsplanung basierend auf dem klinischen Status des individuellen Hüftgelenks sowie dem röntgenologischen Befund. In der Literatur sind unterschiedliche Ansätze beschrieben, um zusätzliche Informationen aus Röntgenbildern zu akquirieren und als Eingabeparameter in Modellrechnungen zu überführen, die eine näherungsweise Berechnung der resultierenden Hüftgelenkskraft R zum Ziel haben. Vergleichende Untersuchungen im Rahmen der vorliegenden Arbeit zeigen, dass sich bei der Berechnung der Amplitude der resultierenden Hüftgelenkskraft R mittels der biomechanischen Modelle von Pauwels, Debrunner und Iglič akzeptable Ergebnisse im Vergleich zu In-vivo-Messungen mit instrumentierten Prothesen ergeben. Lediglich das Modell von Blumentritt zeigte deutlich abweichende resp. höhere Werte. Die Berechnungsergebnisse für die Orientierung von R zeigten eine große Variabilität. Die Ergebnisse waren mehr vom jeweiligen biomechanischen Modell abhängig als von patientenspezifischen Parametern. A consideration of the patient-specific biomechanical situation in the context of the surgical planning of total hip arthroplasty is highly recommended and may have a positive impact on the therapeutic outcome. In current clinical practice, surgical planning is based on the status of the individual hip and its radiographic appearance. Several authors proposed different biomechanical modeling approaches for the calculation of the resultant hip force R on the basis of parameters gathered from plain radiography. The comparative study presented in this paper shows that the biomechanical models by Pauwels, Debrunner, Blumentritt and Iglič provide a good approximation of the magnitude of R when compared to the in vivo data from instrumented prostheses. In contrast, the Blumentritt model resulted in abnormally high values. However, the computational results for the orientation of R show a high variability of all modeling approaches and seem to depend more on the model used than on patient-specific parameters.