Evaluation of zoledronate, cytochalasin-D, and desferrioxamine on osseointegration in an intra-medullary femoral implant model.

OBJECTIVE: The rise in primary and revision surgeries utilizing joint replacement implants suggest the need for more reliable means of promoting implant fixation. Zoledronate-(Zol), cytochalasin-D-(cytoD), and desferrioxamine-(DFO) have been shown to enhance mesenchymal stem cell (MSC) differentiation into osteoblasts promoting bone formation. The objective was to determine whether Zol, cytoD, and DFO can improve fixation strength and enhance peri-implant bone volume about intra-medullary femoral implants. METHODS: 48 Sprague-Dawley female rats were randomized into four treatments, saline-control or experimental: Zol-(0.8 µg/µL), cytoD-(0.05 µg/µL), DFO-(0.4 µg/µL). Implants were placed bilaterally in the femoral canals following injection of treatment solution and followed for 28 days. Mechanical push-out testing and micro-CT were our primary evaluations, measuring load to failure and bone volume. Qualitative evaluation included histological assessment. Data was analyzed with a one-way ANOVA with Holm-Sidak mean comparison testing. RESULTS: Significant results included pushout tests showing an increase in maximum energy for Zol (124%) and cytoD (82%); Zol showed an increase in maximum load by 48%; Zol micro-CT showed increase in BV/TV by 35%. CONCLUSIONS: Our findings suggest that locally applied Zol and cytoD enhance implant mechanical stability. Bisphosphonates and actin regulators, like cytoD, might be further investigated as a new strategy for improving osseointegration.

Use of an IL1-receptor antagonist to prevent the progression of tendinopathy in a rat model.

This study evaluated if inhibiting IL1-ß activity with an IL1-receptor antagonist (IL1-RA) will prevent pathologic changes commonly seen in tendinopathy. Thirty-six Sprague-Dawley retired-breeder rats were divided into three groups having weekly bilateral patellar tendon injections: CON (0.1 ml Saline), CAR (0.1 ml 2% carrageenan), IL1-RA (0.1 ml 2% CAR plus 0.94 mg of the IL1-RA, 2.5 mg/kg). Carrageenan was used to establish tendinopathy in two groups due to its ability to develop tendinopathy in prior studies. Animals were euthanized 3 weeks after initial injection. The CAR group demonstrated significantly (p < 0.05) shorter tendon lengths (8.61 ± 0.38 mm) relative to CON (8.94 ± 0.38 mm) that was prevented in the IL1-RA (9.02 ± 0.30 mm) as well as significantly increased collagenase activity in the CAR (0.061 ± 0.043) compared to CON (0.027 ± 0.015) (p< 0.05). By histological evaluation, the CAR group demonstrated significantly greater inflammation than IL1-RA, and CON (p < 0.05). CAR showed a trend for increased cross-sectional area relative to CON that was absent in the IL1-RA. IL1-RA can effectively inhibit the development of mechanical, chemical, and histologic changes seen with carrageenan-induced tendonitis.

The assessment of postural control with stochastic resonance electrical stimulation and a neoprene knee sleeve in the osteoarthritic knee.

OBJECTIVE: To determine whether the combination of stochastic resonance (SR) electrical stimulation and a neoprene knee sleeve could improve center of pressure (COP) measures of postural sway during single-leg stance in those with knee osteoarthritis (OA). DESIGN: Counterbalanced, repeated-measures intervention study of osteoarthritic adults during 6 different testing conditions: a control condition-control 1 (1); a counterbalance sequence of 4 treatment conditions-no stimulation with sleeve (2), 75% stimulation with sleeve (3), 100% stimulation with sleeve (4), and 150% stimulation with sleeve (5); and a second control condition-control 2 (6). SETTING: University sports medicine research laboratory. PARTICIPANTS: Subjects (N=52) with radiographically determined, minimal-to-moderate medial knee OA. INTERVENTIONS: Neoprene knee sleeve and SR electrical stimulation. MAIN OUTCOME MEASURES: COP displacement in the medial-lateral and anterior-posterior directions was collected to resolve the mean velocity, SD, range, and total path length. RESULTS: No significant differences were found in the study measures between the testing conditions. Additionally, no significant differences were found between the 3 stimulation conditions or between the sleeve-alone and stimulation conditions for any of the study measures. CONCLUSIONS: There were no significant improvements in balance with the use of a neoprene knee sleeve. Additionally, there was no added benefit of the SR stimulation as applied in the current configuration in this population.

Stochastic resonance electrical stimulation to improve proprioception in knee osteoarthritis.

Proprioceptive deficits occur with knee osteoarthritis (OA) and improving proprioception may slow joint degeneration by allowing more appropriate joint loading. Stochastic resonance (SR) stimulation improves balance and the sensitivity of specific mechanoreceptors. Our purpose was to evaluate the effects of SR electrical stimulation combined with a knee sleeve on proprioception in subjects with knee OA. Joint position sense (JPS) was measured in 38 subjects with knee OA during four conditions in both a partial weight-bearing (PWB) and non weight-bearing (NWB) task: no electrical stimulation/no sleeve, no electrical stimulation/sleeve, 50 µA-RMS stimulation/sleeve, and 75 µA-RMS stimulation/sleeve. Subjects also reported their knee pain, stiffness, functionality (WOMAC), and instability. Repeated measures ANOVA and Spearman correlations were performed to investigate differences between the conditions and relationships among the outcome measures. JPS during the 75 µA-RMS stimulation/sleeve and sleeve alone conditions was significantly improved compared to the control condition in the PWB task. However, the 75 µA-RMS stimulation/sleeve and the sleeve alone conditions did not differ from each other. A moderate correlation was found between the improvements with the 75 µA-RMS stimulation/sleeve condition compared to the JPS of the control condition in the PWB task. No differences in JPS were found between the four conditions in the NWB task. Significant correlations were found between the control JPS and WOMAC indices (p<0.005). Improved proprioception during the PWB task was achieved with a sleeve alone and in combination with SR stimulation. The observed correlations suggest that subjects with larger proprioceptive deficits may benefit most from these therapies.