How to Help Heal a Knee Injury
Read Marla Apt's response:
While your student's doctor has given her carte blanche for physical activity, the doctor may not know the various movements of the knee involved in some of the yoga asanas that your student practices. She may already be able to bear weight on the leg and do simple movements without strain, but it will most likely take much longer for her to recover the range of motion in her knee.
Focus on extending the knee in straight-leg asanas such as Utthitha Hasta Padangusthasana, Trikonasana, and Supta Padangusthasana both before and after working on flexion of the knee in bent-knee asanas. In the latter, make sure that her knee is tracking correctly (the upper and lower leg are aligned so that the knee faces directly over the middle of her foot, not turning in or out). If she finds it difficult to keep the knee aligned while bending it, work on the flexibility in her hips so that any kind of rotation required comes from her hip joints rather than her knees. Helping her with mobility and stability in her hips will aid all of her other physical activities as well.
I recommend teaching standing poses to build strength and flexibility around the knee, inner and outer thighs, and hips. If she feels challenged in the standing poses, you can elevate the foot of the recovering knee by putting it on a block to lessen the weight on that leg. When she is ready to begin working on knee flexion in seated poses, such as crossed-leg positions and Virasana (Hero Pose), make sure that she has plenty of height (in the form of props) underneath her seat and be sure her knee doesn't look twisted. Ask her in all of the poses how her knee feels. She may feel stretching in front of the knee, but she shouldn't feel strain or pain in the knee.
After standing and seated poses, I recommend that she practice Supta Padangusthasana (Reclining Big Toe Pose). She should use a belt if she needs in order to fully extend her legs, keeping them firm. Ask her to report to you how she feels after class and whether or not she experiences any swelling after her yoga practices, so that you both can get a sense of what may aggravate the knee.
Finally, it will be helpful to explain to her that the process of healing may be slower than she would like—but that if she practices intelligently and without aggression, she is more likely to have a more complete and lasting recovery.