The patella and the patellar tendon connect the muscles of the front of the upper leg to the muscles of the front of the lower leg. When the patella stays in its groove and the tendon remains uninjured, movement is easy and pain-free. When the patella becomes dislocated or the tendon becomes torn, treatment and rehabilitation must be employed. Rehabilitation exercise for the patella and the patellar tendon range from simple movements and stretches to compound strength-building exercises.

Patellar Mobility

Before stretching can begin, the patella has to be able to be moved without overwhelming pain. Start by sitting down with the injured leg outstretched in front of you. Relax your thigh muscles. With your index finger and thumb, gently push the patella down toward your foot and hold the position for 10 seconds. Return to the starting position. Push the patella to one side and hold it for 10 seconds, then to the other side for 10 seconds. Repeat these movements for five minutes.

Quadriceps and Hamstring Stretches

Prior to stretching, warm up with five to 10 minutes of stationary cycling. Stand upright, facing a wall, and place one hand on the wall for balance. Grab the ankle of the injured leg with your free hand and gently pull your ankle toward your buttocks. Hold this position for 15 to 30 seconds and then return to the starting position. Repeat three times.

Place the heel of your injured leg upon a stool about 15 inches high, keeping your knee straight. Lean toward the foot of your injured leg, bending at the waist. When you feel a light stretch in the back of your leg, hold the position for 15 to 30 seconds. Repeat three times.

Eccentric Squats

In the early stages of rehab, focusing on the eccentric, or downward phase of squats will help restore strength and improve tendon function, according to the "North American Journal of Sports Physical Therapy". Stand on a step bench or other platform set at a 25 degree decline, placing your hand on a stable surface for balance. Shift your weight to your injured leg and lower yourself to a squat, limiting your knee flexion to 60 to 70 degrees. Push up with your uninjured leg to return to your start position. Gradually increase your repetitions until you can perform three sets of 15 repetitions without pain.

Around the World Leg Raises

Strengthening the muscles that influence patellar tracking is an important step in rehab. "Around the world" leg raises with emphasis on the eccentric phase will help balance muscle tension at your knee. Lie supine on the floor, palms down; lift your injured leg in two counts, and lower it for four. Lie on your side with your injured leg on top; keeping your foot parallel to the floor, lift your leg for two counts and lower it for four. Lie on your other side with the injured leg on the bottom, your top leg bent with the foot planted in front of your; lift your injured leg for two counts and lower it for four. Finally, lie face-down; lift your injured leg for two counts and lower it for four. Gradually increase repetitions in all four positions until you can perform 15 without pain.