What is the reason for a total replacement in a 70 yr old? Unless the person is in unbearable pain affecting their quality of life, conservative management is maybe better,but then you have sought many opinions,so it is maybe the only option.
In Kijabe,there was a Dr. Called Tm Mead,but I think he left.The issue there used to be lack of prosthethic components,so check with them how long you have to wait.Look for Dr. Theuri there he will give you sound advice and you might be able to do it as a private patient at the Cure Children's Hospital,same compound with he main Kijabe Hospital.
I never met Dr. Lelei,but i hear he is good and works with a team of young surgeons.