Hello and welcome to HCM,
There are various causes of pain in knee joint.
A detailed clinical history can determine the probable cause of pain in knee joints.
A physically active person like your husband could have suffered injury while playing and this could be the cause of pain.
Sports injuries are usually associated with strain,
sprain or pulling of tendons and ligaments.
Secondly, pain in knee could be due to arthritis at an age of 68 years.
Arthritis or
osteoarthritis is an age related degenerative disorder characterized by
stiffness of joints and pain especially on climbing stairs.
If the pain is due to
sports injury, it will subside after rest.
If the pain aggravates and is not relieved by rest then arthritis is the most probable cause.
You need to consult an orthopedician for clinical assessment and treatment in that case.
Thanks and take care
Dr Shailja Puri