This can be quite a challenge to both client and you (instructor). The repetition of exercises must stay precise and the focus present. Here are a good list of pre surgery exercises that are key for a quick and succesful recovery.

Side-lying straight leg raises:

This exercise is crucial in building your hip abductor muscles located in the buttocks. These muscles stabilize your pelvis while you are standing and walking.

Lie on your side.

Lift your leg straight up toward the ceiling to a distance of about 1 1/2 to 2 feet from your other leg.
Lower your leg and repeat.
Perform up to 3 sets of 10.
Lie on your back and place your problem leg flat on the floor or bed while bending the other leg.
Raise your straightened leg up about 12 inches and hold it there for 5 seconds.
Slowly lower your leg.
Perform up to 3 sets of 5 to 20 repetitions.

Clamshells

This works the external rotators and part of your abductors. Both are important for early ambulation and balance.

Lie on your side with the damaged knee pointed toward the ceiling.
Keeping your heels together, open and close your legs like a clamshell.
Perform up to 3 sets of 5 to 20 repetitions.

KNEE BENDING

This helps maintain your range of motion prior to your surgery.

Sit in a stable chair and bend your knee back as far as possible.
Hold it for 5 seconds and then return it to the resting position.
Perform up to 3 sets of 5 to 20 repetitions.

Sitting kicks

This helps strengthen the quadriceps muscle through its full range of motion.

Sit in a stable chair and raise your leg until it’s straight.
Hold the position for 5 seconds.
Slowly lower your leg.
Perform up to 3 sets of 5 to 20 repetitions.

Chair pushup

This will help strengthen your triceps so they can hold you up when you don’t have the use of both legs after surgery.

Sit in a sturdy chair with arms.
Grasp the arms of the chair and push down on them while raising your body and straightening your arms and elbows.
Slowly lower yourself back onto the chair. This will help strengthen your triceps so they can hold you up when you don’t have the use of both legs after surgery.

Lying kicks

Lie on the floor or a bed and place a rolled blanket or large can under your problematic knee. Straighten your leg and the knee and hold the position for 5 seconds. Slowly lower your leg down and rest. Make sure the back of your knee stays in contact with the object the entire time and the small of your back remains on the floor. This exercise also helps strengthen the quadriceps muscle.

Stomach kickbacks

This helps strengthen your hamstrings and the gluteal muscles in your butt. These muscles are important for getting in and out of chairs and cars.

Lie on your stomach with your leg straight and then slowly bring your whole leg toward the ceiling.
Hold for 2-3 seconds.
Slowly lower your leg.

Standing on one leg with support

This exercise is crucial for maintaining balance and reducing the risk of falls. Perform this exercise as many times as you can per day.

Place yourself in front of a countertop or waist-level bar.
Hold onto the bar and stand on your affected leg for 30 seconds.
Make sure to squeeze your gluteal muscles (in your butt) together to engage your abductors.

Bottom line

Spend at least 15 minutes twice a day doing these exercises. Your ability to build up strength in the muscles around your knee prior to the surgery will greatly impact the speed and quality of your recovery.