Patellar Instability. OrthoInfo Patella Instability Page 1 of 5

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1 Patellar Instability OVERVIEW You have been diagnosed with patella instability. This means that your knee cap (patella) has been partially or completely going out of place and is not tracking well against the front of the thigh bone (femur) in the patellofemoral joint. Patellar instability can become a problem with an injury causing a dislocation or come on gradually with activity related pain. Treatment is directed at getting torn and inflamed tissues to heal and then to improve the strength and direction of the muscle forces acting on the patella. Many patients improve with diligent participation with a home exercise program. Some patients also need bracing or taping for high demand activities like sports. Despite therapy and bracing some patients continue to have difficulty and need surgical realignment to improve patellar tracking. BACKGROUND The patella functions as a pulley in the connection between the muscles in the thigh and the shinbone (tibia). As you bend or straighten your knee, the patella is pulled up or down in a V-shaped groove or notch in the front of the thigh bone (femur). In a normal knee, the kneecap fits nicely in the groove. There are multiple causes for instability. Some people have a shallow notch. Many patients have a well developed central and lateral quadriceps muscle with a weak medial portion. The net effect is that the quadriceps pulls the patella laterally in the groove. Many patients have some degree of ligamentous laxity (increased stretchy-ness) in the ligaments that support the joints. Excess forces, which can occur with a fall, with twisting, or even just standing up wrong, can tear the supporting OrthoInfo Patella Instability Page 1 of 5

2 ligaments and cause the patella to pop out of place. When the patella tracks poorly or if the patella pops out of place, it can lead to overloading and damage to the cartilage surfaces. DIAGNOSIS Many patient present after an injury in which the patella has popped out of place. Many times the patella will also snap back into place by itself. Other times, patients must be brought to the emergency department to have the patella put back in place. Other patients can present with a variety of complaints, including the knee buckling and not supporting your weight, or feeling the patella popping out to the side, or sometimes, just pain and stiffness at the front of the knee with activity. If there has been a dislocation, there may be significant pain and swelling. During the examination, your doctor will ask you to walk around and to straighten and bend your knee, while feeling the area around the kneecap and take measurements to determine if the bones are out of alignment or if the thigh muscles are weak. X-rays may be done to see how the kneecap fits in its groove. Your doctor will also want to eliminate other possible reasons for the pain, such as a tear in the cartilage or ligaments of the knee. TREATMENT If the patella has popped totally out of its groove (dislocated), the first step is to return it to its proper place. This process is called reduction. Sometimes this happens spontaneously; other times, your doctor will have to apply gentle force to push the kneecap back in place. A dislocation sometimes damages the cartilage under the patella and cause additional pain and even arthritis. Arthroscopic surgery is sometimes needed to address this cartilage damage. With a dislocation, there is often tearing of the medial supporting ligaments and stretching or bruising of the lateral supporting ligaments. If the patella has dislocated, there will be significant pain and swelling and sometimes there can be significant pain and swelling with an incomplete dislocation. If there is significant pain and swelling, treatment starts with a period and rest and immobilization. Occasionally, a long cast is used, but most times a knee immobilizer is used to hold the knee straight to allow for the pain and swelling to improve. Weight bearing is allowed, but may be painful. Crutches can be used, until you are comfortable walking without them. OrthoInfo Patella Instability Page 2 of 5

3 After severe pain and swelling have improved, it is important to rehab the knee by working with a physical therapist. Pain may continue on a lower level and is often activity related. Options for addressing pain include activity modifications and symptomatic treatments, including anti-inflammatory medications, ice and heat. Some patients also need bracing or taping for high demand activities like sports. Despite therapy and bracing some patients continue to have difficulty and need surgical realignment to improve patellar tracking. PHYSICAL THERAPY The best means of improving knee mechanics is stretching the hamstrings and balancing the quadriceps to improve patellar tracking. The physical therapist can recommend exercises to reduce the inflammation. Exercises can also be used to stretch, strengthen, and balance the thigh muscles that control the kneecap in the groove. When thigh muscles are strong and balanced, the kneecap will move through the groove accurately and with less pressure. When you stretch, always stretch slowly without bouncing, until you feel your muscles stretch moderately. If you feel significant pain, back off or discontinue. The physical therapist will show you a set of exercises to do at home twice each day. It is important to do these stretches to get the maximum benefit. The physical therapists may also have special tools or equipment like ultrasound or whirlpool treatments to help loosen up the knee and reduce inflammation. If available, these tools can help make the knee feel better sooner. The two most important components of the home program are stretching the hamstring muscles and strengthening the medial part of the quadriceps thigh muscle. Below are two examples to get started. The therapist will work to find the best set of stretches and exercises for you. Standing Hamstring Stretch: Prop leg up on chair or table. Hold the knee straight. Place hands on lower leg just below the knee. With back straight, bend forward at the hip until you feel a stretch under your thigh. Hold ten seconds and relax. "T" Exercises: While seated on the floor. Put a two-pound weight around your ankle. Lock your knee and raise your leg 12 inches off the floor. Slowly, draw a "T" with your foot. Repeat with other leg. Start with 10 repetitions on each leg. Each day that the knee feels OrthoInfo Patella Instability Page 3 of 5

4 good, do 5 more repetitions. Once you are doing 30 repetitions, increase the weight by 1 pound and restart with 10 repetitions. Continue this process, up to 10 pounds. ACTIVITY MODIFICATIONS Activity is the main contributing factor to pain. Reducing activity will reduce pain. If the pain is tolerable, it is okay to continue with activity. Indications to reduce pain are decreased performance, limping, whining, or poor tolerance for other important activities like homework and household chores. If your knees hurt too much to carry out the garbage, you shouldn t be playing basketball. If needed parents will need to set the level of activity to help control symptoms. While it may be possible to figure out exactly how much time can be spent playing soccer or bike riding without becoming symptomatic, this may be difficult determine and even more difficult to enforce. My guidelines for activity modifications are to adjust activity by broad levels every 2 weeks. Activity levels can be set however the parents choose, but my recommendation is to consider four broad levels. Level one is full activity including gym and sports. Level two is no gym or sports, but running and jumping are allowed in play around the house. Level three is no running or jumping. Level four is required crutch walking. Decisions for setting the activity level are based on the family assessment of frequency of pain complaints, presence of a limp, cooperation with chores and schoolwork, and the knee motion. If these symptoms worsen, activity is decreased one level. If symptoms are acceptable or improve, then activity is maintained or increased one level. Schools are required to make appropriate accommodations for children with medical conditions. If you want the school to work with you, you may need to notify school personnel of the child s medical condition and work out a system for keeping them informed regarding activity restrictions. PAIN MANAGEMENT Appropriate pain interventions include pain medications and any other interventions that help with the pain. The use of medications like acetaminophen (Tylenol) or ibuprofen (Motrin, Advil, Etc) should be liberal as these medications are quite safe. Antiinflammatory medications are most commonly used for management of arthritis and we know from these patients, that (1) these medications don t wear out or lose effectiveness (2) tolerance/addiction are not issues, (3) they work better if taken in advance of activities which might cause symptoms, and (4) they work even better if they are taken on the regular schedule. Symptoms which arise at school are best managed with rest or sitting, not narcotic medications. If needed, acetaminophen can be given in addition to the anti-inflammatory medications. Other interventions for pain include massage, stretching, ice, heating pads, and warm baths. SURGICAL OPTIONS OrthoInfo Patella Instability Page 4 of 5

5 Surgical options for treatment of patellar instability are limited reserved for cases that do not improve with symptomatic care, followed by a good and prolonged effort with a physical therapist directed stretching and strengthening program. Options for surgery include soft tissue realignment and bony procedures. Bony procedures are reserved for mature individuals with closed growth plates. Soft tissue procedures includes some combination of repair of the stretched or torn medial retinaculum, possible release of tight lateral retinaculum, possible advancement of the medial portion of the quadriceps, and possible tenodesis with one of the hamstring tendons. Procedures which modify the bone structure include medial advancement of the tibial tubercle and/or osteotomies to realign the tibia or femur. Details for the post-operative care vary depending on the procedure, but typically recovery time is 2-3 months and sometimes longer. PROGNOSIS The prognosis for good functional recovery is good. In general, patella instability improves with physical therapy. Some patient get added benefit from bracing for sports. Surgery is reserved for severe and refractory cases. Patellar realignment procedures are not a substitute for the physical therapy program. Patients who do not get adequate relief from physical therapy and bracing, surgery can provide some improvement to stability and pain. Patients are at risk for long term symptoms and arthritis. It is important to continue with exercises and stretches as needed to maintain good patellar tracing. MORE INFORMATION Further information can be obtained on the internet. Your local public library can help you explore these sources if you are interested. Two good sites for expert and peer reviewed information are the American Academy of Orthopedic Surgeons at and FEEDBACK If you have questions or comments, please contact the office or submit them to the web site at OrthoInfo Patella Instability Page 5 of 5