In patients eligible for meniscal surgery who first receive physical therapy, multivariable prognostic models cannot predict who will eventually undergo surgery

Purpose Although physical therapy is the recommended treatment in patients over 45 years old with a degenerative meniscal tear, 24% still opt for meniscal surgery. The aim was to identify those patients with a degenerative meniscal tear who will undergo surgery following physical therapy. Methods The data for this study were generated in the physical therapy arm of the ESCAPE trial, a randomized clinical trial investigating the effectiveness of surgery versus physical therapy in patients of 45-70 years old, with a degenerative meniscal tear. At 6 and 24 months patients were divided into two groups: those who did not undergo surgery, and those who did undergo surgery. Two multivariable prognostic models were developed using candidate predictors that were selected from the list of the patients' baseline variables. A multivariable logistic regression analysis was performed with backward Wald selection and a cut-off of p < 0.157. For both models the performance was assessed and corrected for the models' optimism through an internal validation using bootstrapping technique with 500 repetitions. Results At 6 months, 32/153 patients (20.9%) underwent meniscal surgery following physical therapy. Based on the multivariable regression analysis, patients were more likely to opt for meniscal surgery within 6 months when they had worse knee function, lower education level and a better general physical health status at baseline. At 24 months, 43/153 patients (28.1%) underwent meniscal surgery following physical therapy. Patients were more likely to opt for meniscal surgery within 24 months when they had worse knee function and a lower level of education at baseline at baseline. Both models had a low explained variance (16 and 11%, respectively) and an insufficient predictive accuracy. Conclusion Not all patients with degenerative meniscal tears experience beneficial results following physical therapy. The non-responders to physical therapy could not accurately be predicted by our prognostic models.Orthopaedics, Trauma Surgery and Rehabilitatio

Crop growth and viability of seeds on Mars and Moon soil simulants

If humans are going to establish a base on the Moon or on Mars they will have to grow their own crops. An option is to use Lunar and Martian regolith. These regoliths are not available for plant growth experiments, therefore NASA has developed regolith simulants. The major goal of this project was to cultivate and harvest crops on these Mars and Moon simulants. The simulants were mixed with organic matter to mimic the addition of residues from earlier harvests. Ten different crops, garden cress, rocket, tomato, radish, rye, quinoa, spinach, chives, pea and leek were sown in random lines in trays. Nine of the ten species grew well with the exception of spinach. It was possible to harvest edible parts for nine out of ten crops. The total biomass production per tray was highest for the Earth control and Mars soil simulant and differed significantly from Moon soil simulant. The seeds produced by three species were tested for germination (radish, rye and cress). The germination on Moon soil simulant was significantly lower in radish than for the Earth control soil

Crop Growth and Viability of Seeds on Mars and Moon Soil Simulants

If humans are going to establish a base on the Moon or on Mars, they will have to grow their own crops. An option is to use Lunar and Martian regolith. These regoliths are not available for plant growth experiments, therefore NASA has developed regolith simulants. The major goal of this project was to cultivate and harvest crops on these Mars and Moon simulants. The simulants were mixed with organic matter to mimic the addition of residues from earlier harvests. Ten different crops, garden cress, rocket, tomato, radish, rye, quinoa, spinach, chives, pea and leek were sown in random lines in trays. Nine of the ten species grew well with the exception of spinach. It was possible to harvest edible parts for nine out of ten crops. The total biomass production per tray was highest for the Earth control and Mars soil simulant and differed significantly from Moon soil simulant. The seeds produced by three species were tested for germination (radish, rye and cress). The germination on Moon soil simulant was significantly lower in radish than for the Earth control soil

Radiographic, histologic, and chemical evaluation of bioresorbable 70/30 poly-L-lactide-CO-D, L-lactide interbody fusion cages in a goat model

STUDY DESIGN: A study of lumbar interbody fusion using polylactic acid-based bioresorbable fusion cages in a goat model. OBJECTIVE: To evaluate the effect of polylactic acid polymer composition, and internal stabilization on the rate and quality of interbody fusion. SUMMARY OF BACKGROUND DATA: A spinal cage should provide an appropriate biomechanical environment to facilitate interbody fusion. Previous studies have shown that bioresorbable polylactic acid-based cages can provide adequate stability for spinal fusion. However, at present and to our knowledge, the best bioresorbable materials, optimal cage stiffness, and desired period over which the cage should biodegrade are unknown. METHODS: Interbody fusions were performed at L3-L4 level in 35 skeletally mature Dutch milk goats. Titanium and poly-L-lactide-CO-D,L-lactide (PLDLLA) cages were implanted at random as stand-alone cages. In addition, PLDLLA cages were implanted with anterior fixation. The goats were euthanized at 3, 6, or 12 months. Radiographic, magnetic resonance imaging, histologic, and histomorphometric analyses were performed on retrieved segments. Chemical analysis was used to assess degradation of the retrieved PLDLLA cages. Beforehand, chemical and mechanical degradation of the PLDLLA cages were assessed in vitro. RESULTS: At 3 months, bone graft was almost completely remodeled. Endochondral bone formation was observed in all specimens. At 6 months, 50% of the PLDLLA stand-alone cages and 83% of the PLDLLA anterior fixation cages were fused. At 12 months, 38% of the PLDLLA stand-alone and 83% of the titanium cages realized fusion. A very mild and dispersed foreign body reaction was seen in all PLDLLA specimens. E-beam sterilized PLDLLA cages degraded more rapidly in vivo as compared to both, PLDLLA cages in vitro, and ethylene oxide sterilized poly-L-lactic acid cages in vivo. CONCLUSIONS: Within the 3-6-month period, PLDLLA stand-alone cages provided insufficient mechanical stability, which manifested as cracking and deformation of the cages and lower fusion rates. This result implies that within this time, additional stabilization is required; supplemental internal fixation proved sufficient to obtain successful fusion. In all cases, only a mild host response was seen, indicating good biocompatibility