Patellar Dislocation and Subluxation

with Phase I Rehab

Injuries to the knee often include kneecap (patellar) dislocation or subluxation. The patella is a V-shaped bone that sits in a groove in the thigh bone (trochlea). A patellar dislocation occurs when the kneecap is displaced from the trochlea, and the joint surfaces are no longer touching. A subluxation is a similar injury, where the kneecap becomes displaced, but the joint surfaces are still touching. Patellar dislocations and subluxations are most common in adolescents and younger adults.

SYMPTOMS

  • Severe pain in the front of the knee when attempting to move the knee.

  • A feeling of the knee giving way.

  • Tenderness, swelling, and bruising (contusion) of the knee.

  • Numbness or paralysis below the dislocation, from pinching, cutting, or pressure on the blood vessels or nerves (uncommon).

  • Visible deformity, especially if the dislocation of the kneecap occurs towards the outside of the knee.

  • Lump on the inner knee, which is the end of the inner part of the thigh bone (femur).

CAUSES

Patellar dislocations are caused by a force placed on the kneecap, that is strong enough to displace the bone from its proper alignment. Common causes of injury include:

  • Direct hit (trauma) to the knee.

  • Twisting or pivoting injury to the lower limb, when the foot is planted on the ground.

  • Powerful muscle contraction.

  • Birth defect (congenital abnormality), such as shallow or malformed joint surfaces.

RISK INCREASES WITH:

  • Contact sports (football, rugby, soccer), sports that require jumping and landing (basketball, volleyball), or sports in which cleats are worn on shoes.

  • People with wide pelvis, knocked knees, shallow or malformed joint surfaces.

  • Previous knee injury.

  • Poor strength and flexibility.

PREVENTION

  • Warm up and stretch properly before activity.

  • Maintain physical fitness:

  • Strength, flexibility, and endurance.

  • Cardiovascular fitness.

  • For jumping or contact sports, protect the kneecap with supportive devices (elastic bandages, tape, braces, knee sleeves with a hole for the patella and a built-up outer side, or straps to pull the patella inward, or knee pads).

  • Use cleats of proper length.

PROGNOSIS

If treated properly, patellar dislocations and subluxations usually require at least 6 weeks to heal.

RELATED COMPLICATIONS

  • Associated fracture or joint cartilage injury.

  • Damage to nearby nerves or major blood vessels (rare).

  • Longer healing time or recurring dislocation, if activity is resumed too soon.

  • Excessive bleeding within the knee, due to dislocation.

  • Kneecap pain and giving way, often due to inadequate or incomplete rehabilitation.

  • Unstable or arthritic joint, following repeated injury or delayed treatment.

TREATMENT

Patellar dislocations and subluxations require immediate realigning of the bones (reduction). Realigning is often completed by hand. However, surgery is sometimes needed. After realignment, treatment first involves the use of ice and medicine, to reduce pain and inflammation. Elevating the injured knee above the level of the heart will also help reduce inflammation. Restraining the knee is often needed, to allow for healing, for up to 6 weeks. After restraint, it is important to perform strengthening and stretching exercises to help regain strength and a full range of motion. These exercises may be completed at home or with a therapist.

MEDICATION

  • If pain medicine is needed, nonsteroidal anti-inflammatory medicines (aspirin and ibuprofen), or other minor pain relievers (acetaminophen), are often advised.

  • Do not take pain medicine for 7 days before surgery.

  • Prescription pain relievers may be given, if your caregiver thinks they are needed. Use only as directed and only as much as you need.

HEAT AND COLD

  • Cold treatment (icing) should be applied for 10 to 15 minutes every 2 to 3 hours for inflammation and pain, and immediately after activity that aggravates your symptoms. Use ice packs or an ice massage.

  • Heat treatment may be used before performing stretching and strengthening activities prescribed by your caregiver, physical therapist, or athletic trainer. Use a heat pack or a warm water soak.

SEEK MEDICAL CARE IF:

  • Pain, tenderness, or swelling gets worse, despite treatment.

  • You experience pain, numbness, or coldness in the foot.

  • Blue, gray, or dark color appears in the toenails.

  • Any of the following signs of infection occur after surgery: fever, increased pain, swelling, redness, drainage of fluids, or bleeding in the affected area.

  • New, unexplained symptoms develop. (Drugs used in treatment may produce side effects.)

EXERCISES

PHASE I EXERCISES

RANGE OF MOTION (ROM) AND STRETCHING EXERCISES - Patellar Dislocation and Subluxation Phase I

  • FIRST TIME DISLOCATIONS OR SUBLUXATIONS:

If you have dislocated or subluxed your kneecap for the first time, your caregiver may ask you to wear a knee brace for up to 6 weeks after your injury. This brace will keep your knee completely straight so that the healing tissues are not disrupted by your knee movement. Your caregiver may allow some motion at your knee by using a hinged brace or by allowing you to take your brace off for a limited amount of time to gently bend and straighten your knee. If this is the case, closely follow your caregiver's directions, in order to allow the best recovery.

  • CHRONIC OR REPEATED DISLOCATIONS OR SUBLUXATIONS:

If you have chronic or repeated dislocations or subluxations, your caregiver will likely not ask you to use a brace. He or she will likely have you begin gentle range of motion activities, within the range that is comfortable for you.

Once you are allowed to start moving your knee, these are some of the initial exercises that may be included in your rehabilitation program. Continue to perform them until you see your caregiver again or until your symptoms go away. While completing these exercises, remember:

  • Restoring tissue flexibility helps normal motion to return to the joints. This allows healthier, less painful movement and activity.

  • An effective stretch should be held for at least 30 seconds.

  • A stretch should never be painful. You should only feel a gentle lengthening or release in the stretched tissue.

RANGE OF MOTION - Knee Flexion, Active

  • Lie on your back with both knees straight. (If this causes back discomfort, bend your opposite knee, placing your foot flat on the floor.)

  • Slowly slide your heel back toward your buttocks until you feel a gentle stretch in the front of your knee or thigh.

  • Hold for __________ seconds. Slowly slide your heel back to the starting position.

Repeat __________ times. Complete this exercise __________ times per day.

RANGE OF MOTION - Knee Flexion and Extension, Active-Assisted

  • Sit on the edge of a table or chair with your thighs firmly supported. It may be helpful to place a folded towel under the end of your right / left thigh.

  • Flexion (bending): Place the ankle of your healthy leg on top of the other ankle. Use your healthy leg to gently bend your right / left knee until you feel a mild tension across the top of your knee.

  • Hold for __________ seconds.

  • Extension (straightening): Switch your ankles so your right / left leg is on top. Use your healthy leg to straighten your right / left knee until you feel a mild tension on the backside of your knee.

  • Hold for __________ seconds.

Repeat __________ times. Complete this exercise __________ times per day.

STRETCH - Knee Flexion, Supine

  • Lie on the floor with your right / left heel and foot lightly touching the wall. (Place both feet on the wall if you do not use a door frame.)

  • Without using any effort, allow gravity to slide your foot down the wall slowly until you feel a gentle stretch in the front of your right / left knee.

  • Hold this stretch for __________ seconds. Then return the leg to the starting position, using your healthy leg for help, if needed.

Repeat __________ times. Complete this stretch __________ times per day.

STRENGTHENING EXERCISES - Patellar Dislocation and Subluxation Phase I

These exercises may help you when beginning to rehabilitate your injury. They may resolve your symptoms with or without further involvement from your physician, physical therapist or athletic trainer. While completing these exercises, remember:

  • Muscles can gain both the endurance and the strength needed for everyday activities through controlled exercises.

  • Complete these exercises as instructed by your physician, physical therapist or athletic trainer. Increase the resistance and repetitions only as guided by your caregiver.

STRENGTH - Quadriceps, Isometrics

  • Lie on your back with your right / left leg extended and your opposite knee bent.

  • Gradually tense the muscles in the front of your right / left thigh. You should see either your kneecap slide up toward your hip or increased dimpling just above the knee. This motion will push the back of the knee down toward the floor, mat, or bed on which you are lying.

  • Hold the muscle as tight as you can, without increasing your pain, for __________ seconds.

  • Relax the muscles slowly and completely in between each repetition.

Repeat __________ times. Complete this exercise __________ times per day.

STRENGTH - Quadriceps, Straight Leg Raises

Quality counts! Watch for signs that the quadriceps muscle is working, to be sure you are strengthening the correct muscles and not "cheating" by substituting with healthier muscles.

  • Lay on your back with your right / left leg extended and your opposite knee bent.

  • Tense the muscles in the front of your right / left thigh. You should see either your kneecap slide up or increased dimpling just above the knee. Your thigh may even shake a bit.

  • Tighten these muscles even more and raise your leg 4 to 6 inches off the floor. Hold for __________ seconds.

  • Keeping these muscles tense, lower your leg.

  • Relax the muscles slowly and completely between each repetition.

Repeat __________ times. Complete this exercise __________ times per day.

STRENGTH - Hip Abductors, Straight Leg Raises

Be aware of your form throughout the entire exercise, so that you exercise the correct muscles. Poor form means that you are not strengthening the correct muscles.

  • Lie on your side so that your head, shoulders, knee and hip line up. You may bend your lower knee to help maintain your balance. Your right / left leg should be on top.

  • Roll your hips slightly forward, so that your hips are stacked directly over each other and your right / left knee is facing forward.

  • Lift your top leg up 4-6 inches, leading with your heel. Be sure that your foot does not drift forward or that your knee does not roll toward the ceiling.

  • Hold this position for __________ seconds. You should feel the muscles in your outer hip lifting. (You may not notice this until your leg begins to tire.)

  • Slowly lower your leg to the starting position. Allow the muscles to fully relax before beginning the next repetition.

Repeat __________ times. Complete this exercise __________ times per day.

STRENGTH - Hip Extensors, Straight Leg Raises

  • Lie on your stomach on a firm surface.

  • Tense the muscles in your buttocks to lift your right / left leg about 4 inches. If you cannot lift your leg this high without arching your back, place a pillow under your hips.

  • Keep your knee straight. Hold __________ seconds.

  • Slowly lower your leg to the starting position and allow it to relax completely before completing the next repetition.

Repeat __________ times. Complete this exercise __________ times per day.

STRENGTH - Hip Adductors, Straight Leg Raises

  • Lie on your side so that your head, shoulders, knee and hip line up. You may place your upper foot in front, to help maintain your balance. Your right / left leg should be on the bottom.

  • Roll your hips slightly forward, so that your hips are stacked directly over each other and your right / left knee is facing forward.

  • Tense the muscles in your inner thigh and lift your bottom leg 4-6 inches. Hold this position for __________ seconds.

  • Slowly lower your leg to the starting position. Allow the muscles to fully relax before beginning the next repetition.

Repeat __________ times. Complete this exercise __________ times per day.