It is now nearly 5 years since you gave me a part knee replacement.  In that that time I have been very active culminating in a recent trek in the Himalayas, I did a demanding 12-day trek to Everest Base Camp. This has been on my bucket list for a very very long time and prior to the operation it is a trip I could not possibly have even contemplated, I struggled to walk down any kind of incline for any period without an adverse reaction, I covered the many climbs and descents over rough terrain without any adverse reaction whatsoever; remarkable. My heartfelt thanks for enabling this.