I grabbed the opportunity to be offered hydrotherapy at week 4 (ish) post op because I was struggling to make progress with knee flexion and was ‘behind’ where they would like me to be regards rehab.
Since I have been attending hydrotherapy (2 x weekly ever since) I have seen huge gains in how the knee functions and bends. The water in the hydrotherapy pool is much warmer than your standard swimming pool, which means making the joint limber is a lot easier. That plus the support of the water and I have been able to trial new exercises in the pool before I can do them on land.
Here is what I have been doing and how I have progressed the exercises. Please note, this program started off with physio guidance but I further developed it using my own fitness knowledge as a personal trainer.
Board stomp / flipper walking / bicycle legs
Put a float beneath your foot, stamp the leg down to the floor, and lift.
With flippers on both feet (the slightly shorter ones used for swimming training) walk up and down the pool. This might sound easy but it requires a lot of knee bend to clear the floor. Focus on NOT hitching the hip up in the process.
Bicycle legs (both backwards and forwards). easiest done in the corner, arms on the side for support. cycle the legs forwards and backwards, trying to get as much bend as you can.
Walking lunges, seated squats, single leg lunges
Walking lunge up and down the pool. use arms for float support. In a hydrotherapy pool there should be a deep and a shallow end. It will be easier in deeper water.
If there is a seated bench under water, great, but if not, just make this a normal squat. Focus on keeping chest up, weight even on both legs, bend knees as much as you can
start off by standing hanging onto the side for support. stand on operated leg, other knee bent with foot behind on the floor. Aim is to bend the knee enough so the other knee reaches the floor. Progress this to using no arms for support. Further progress this so other foot does not even touch the floor.
Pistol squats, hop and balance, lunge to pistol squat
This time, you are going to do the single leg lunge with your good leg extended out in front of you. You might need arms for balance at first. Lower yourself as far as you possibly can. This can be started from seated and progressed to free standing.
On the operated leg, hop the length of the pool from shallow to deep, then place the good leg foot on the knee of the operated leg (yoga pose). Using the arms for flotation as little as possible, hold the single leg balance as long as you can up to 30-45 sec. Repeat heading back to the shallow end and then repeat the balance hold. It will be much harder with less water to support you.
This is a moving exercise working on balance on the operated leg while your other leg is moving and the centre of gravity is shifting. From a lunge position, standing on operated leg, lunge so other knee almost reaches the floor, then straighten the leg and bring it around in front of you to a pistol squat position, still holding bended knee throughout the movement. Reverse the leg back to the starting position.