Conclusion
Cutting human cartilage with US in the presence of 300 or 600 mOsm/L media was chondroprotective compared to normal (non-US) scalpel cutting in 300 mOsm/L medium. These results suggest chondroprotection can be achieved while cutting using a US scalpel and raised osmolarity, potentially improving cartilage regeneration and repair following injury.
Methods
A scalpel (no. 15) was mounted on an ultrasonic transducer to resonate at 35 kHz with 30 μm vibrational displacement. Thirty-six fresh human femoral cartilage samples were divided into four groups based on ultrasonic activation (US or non-US) and saline osmolarity (300 or 600 mOsm/L). Cell viability was assessed using a live/dead cell assay and analysed quantitatively by confocal microscopy. Histology illustrated tissue surface changes at the cut site.
Results
The overall chondrocyte death percentage at both the US and non-US cut sites showed comparable results (p > 0.05) in both osmolarities. However, the zone of chondrocyte death was reduced by 31 ± 5% and 36 ± 6%, respectively, when comparing US cutting at 300 mOsm/L and 600 mOsm/L to the control group (non-US cutting; 300 mOsm/L) (p < 0.05). The width of the cut was consistent at both sites, regardless of the method of cutting.