What is chondromalacia patellae?
Chondromalacia patellae, also known as “runner’s knee,” is a condition where the cartilage on the undersurface of the patella (kneecap) deteriorates and softens. This condition is common among young, athletic individuals, but may also occur in older adults who have arthritis of the knee.
Chondromalacia is often seen as an overuse injury in sports, and sometimes taking a few days off from training can produce good results. In other cases, improper knee alignment is the cause and simply resting doesn’t provide relief. The symptoms of runner’s knee are knee pain and grinding sensations, but many people who have it never seek medical treatment.
What causes chondromalacia patellae?
Your kneecap normally resides over the front of your knee joint. When you bend your knee, the backside of your kneecap glides over the cartilage of your femur or thigh bone at the knee. Tendons and ligaments attach your kneecap to your shinbone and your thigh muscle to the kneecap. When any of these components fails to move properly, it can cause your kneecap to rub up against your thigh bone. This abnormal rubbing can lead to deterioration in the patella, resulting in chondromalacia patellae or runner’s knee.
Improper kneecap movement may result from:
- poor alignment due to a congenital condition
- weak hamstrings and quadriceps (the muscles in the back and front of your thighs)
- muscle imbalance between the adductors and abductors (the muscles on the outside and inside of your thighs)
- repeated stress to your knee joints, such as from running, skiing, or jumping
- a direct blow or trauma to your kneecap
Who is at risk for chondromalacia patellae?
There are a variety of factors that may increase your risk for developing chondromalacia patellae.
Adolescents and young adults are at high risk for this condition. During growth spurts, the muscles and bones develop rapidly, which may contribute to short-term muscle imbalances.
Females are more likely than males to develop runner’s knee, as they typically possess less muscle mass than males. This can cause abnormal knee positioning, as well as more lateral (side) pressure on the kneecap.
Flat feet may place more stress on your knee joints than in people who have higher arches in their feet.
A prior injury to the kneecap, such as a dislocation, can increase your risk of developing runner’s knee.
High activity level
If you have a high activity level or engage in frequent exercises that place pressure on your knee joints, this can increase the risk for knee problems.
Runner’s knee can also be a symptom of arthritis, a condition causing inflammation to the joint and tissue. Inflammation can prevent the kneecap from functioning properly.
Symptoms are similar to that of patellofemoral pain syndrome with pain and swelling at the front of the knee especially over and around the kneecap or patella. It is often worse when walking downstairs or after sitting for long periods, known as movie-goers knee or theater knee. A grinding or clicking feeling called cerpitus can be felt when bending and straightening the knee.
Diagnosing and grading chondromalacia patellae
Your doctor will look for areas of swelling or tenderness in your knee. They may also look at how your kneecap aligns with your thigh bone. A misalignment can be an indicator of chondromalacia patellae. Your doctor may also apply resistive pressure to your extended kneecap to determine the tenderness and severity.
Afterward, your doctor may request any of the following tests to aid in diagnosis and grading:
- X-rays to show bone damage or signs of misalignment or arthritis
- magnetic resonance imaging (MRI) to view cartilage wear and tear
- arthroscopic exam, a minimally invasive procedure involving an endoscope and camera inserted into the knee joint.
There are four grades, ranging from grade 1 to 4, that designate the severity of runner’s knee. Grade 1 is least severe, while grade 4 indicates the greatest severity.
- Grade 1 severity indicates softening of the cartilage in the knee area.
- Grade 2 designates a softening of the cartilage along with abnormal surface characteristics. This usually indicates the beginning of tissue erosion.
- Grade 3 shows thinning of cartilage with active deterioration of the tissue.
- Grade 4, the most severe grade, indicates exposure of the bone with a significant portion of cartilage deteriorated. Bone exposure means bone-to-bone rubbing is likely occurring in the knee.
Tips to prevent chondromalacia patellae
You can help reduce your risk of developing runner’s knee by following these recommendations:
Avoid repeated stress to your kneecaps. Wear kneepads if you have to spend time on your knees.
Create muscle balance by strengthening your quadriceps, hamstrings, abductors, and adductors.
Wear shoe inserts that correct flat feet by increasing your arch. This will decrease the amount of pressure placed on your knees and may realign the kneecap.
Finally, excess body weight may stress your knees. Maintaining a healthy body weight can help take pressure off the knees and other joints. You can take steps to lose weight by reducing your sugar and fat intake, eating plenty of vegetables, fruits, and whole grains, and exercising for at least 30 minutes day, five times a week.
Examination of the knee may be divided into four categories -look, move, feel, X-ray.
I. Look – the joint appearance is usually normal but occasionally there may be a slight effusion.
2. Move – passive movements are usually full and painless but repeated extension of the knee from flexion will produce pain and grating under the patella especially if the articular surfaces are pressed together.
3. Feel (i) Pain and crepitus will be felt if the patella is rubbed against the femur, either vertically or horizontally, with the knee in full extension. (ii) By displacing the patella medially or laterally, the patellar margins and their articular surfaces may be felt. Tenderness of one or other margin may be elicited.. It is more frequently the medial one.. (iii) Resistance of a static quadriceps contraction, by placing the hand proximal to the upper border of the patella, will produce a sharp pain under the patella. This may be apparent in both knees but more severe on the affected side.
4. X-ray – a skyline view of the patellofemoral joint is needed to detect any radiological change. In all, hut the most advanced cases, there is no convincing radiological change. In the later stages, the patellofemoral joint space narrows and still later osteoarthritic changes appear.
First of all the hardest task for the physiotherapist is to ascertain the disease. At first it is necessary to inspect the position and posture of the patient. Look at eventual asymmetries, like the limb alignment in standing, internal femoral rotation, anterior or posterior pelvic tilt, hyperextended or ‘locked back’ knees, genu varum or valgum and abnormal pronation of the foot. When there are asymmetries or abnormal positions in one of these anatomic structures, it will affect the patient’s gait pattern.
Next you have to test the mobility / range of motion (ROM) of the joint. With chondromalacia there is very often a limitation in the ROM. When there is a bursitis present, a passive flexion or active extension will be painful. You can also test the isometric power of the muscles, here especially the quadriceps. The affected leg will show a loss of power, according to the non-injured leg. There are also some specific test to diagnose anterior knee pain syndrome, of which CMP is a part:
Patellar-grind test a.k.a. Clarke’s sign :
The purpose of this test is to detect the presence of patellofemoral joint disorder. Patient is positioned in supine or long sitting with the involved knee extended. The examiner places the web space of his hand just superior to the patella while applying pressure. The patient is instructed to gently and gradually contract the quadriceps muscle. A positive sign on this test is pain in the patellofemoral joint.
Extension-resistance test :
The extension resistance test is used to perform a maximal provocation on the muscle-tendon mechanism of the extensor muscles. The extension resistance test is positive when the affected knee shows less power to hold the pressure. If positive we can say the extensor mechanism of the knee is disturbed. The patient is instructed to perform an extension of the knee joint, while the therapist exercises pressure in the opposite direction (flexion). The therapist evenly builds up his pressure, the patient is to allow no movement in the joint. Resistance tests should be performed on both knees and compared to one another
The critical test:
This test is done with the patient in high sitting. The patient must do isometric quadriceps contractions in 5 different angles (0°, 30°, 60°, 90° and 120°) while the femur is externally rotated. The contraction must be sustained for 10 seconds. If pain is produced by the isometric contractions, then the leg has to be brought into full extension. In this position the patella and femur have no more contact. The lower leg of the patient is supported by the therapist so the quadriceps can be fully relaxed. When the quadriceps is relaxed, the therapist is able to glide the patella medially. This glide is maintained while the isometric contractions are performed again. If this reduces the pain and the pain is patellofemoral in origin, there is a higher chance in a favourable outcome.
Note that it is still possible to diagnose incorrectly, these test may help in determine chondromalacia but it is best to rule out other diagnoses.
Exercise and education are two very important parts of therapy. The education should help the patient to understand the problem and how he should deal with it for an optimal recovery. The exercises should be focused on stretching and strengthening the knee. Stretching of the hamstring, iliotibial band, quadriceps and gastrocnemius are the most important. Strengthening exercises of the gluteal muscle. (level1) It is also proven that fire needling and acupuncture in high stress points could relieve clinical symptoms of chondromalacia patellae and recovers the biodynamicall structure of patellae. (level 1A)
If conservative measures fail, though, there are a number of possible surgical procedures. These procedures take place when the symptoms remain the same after the conservative measures.
- The first option is called shaving, also known as chondrectomy. This treatment includes shaving down the damaged cartilage, just to the not-damaged cartilage underneath. The success of this treatment depends on the severity of the cartilage damage.
Drilling is also a method that is frequently used to heal the damaged cartilage. However, this procedure has not so far been proved to be effective. More localized degeneration might respond better to drilling small holes through the damaged cartilage. This facilitates the growth of the healthy tissue through the holes, from the layers underneath.
- The most severe surgical treatment is a full patellectomy. This operation is only used when no other procedures were helpful. A big consequence is that the quadriceps will weaken very hard. Two potential treatments may be successful.
- Replacement of the damaged cartilage : The damaged cartilage is replaced by a polyethylene cap prosthesis. Early results have been good, but eventual wearing of the opposing articular surface is inevitable.
- Autologous chondrocyte transplantation under a tibial periosteal patch.
- Simply removing the cartilage is not enough to cure chondromalacia patellae. The biomechanical problem needs addressing and there are various procedures to aid re-alignment :
1. Thightening of the medial capsule (MC) : If the MC is lax, it can be tightened by pulling the patella back into its correct alignment.
2. Lateral release : A very tight lateral capsule will pull the patella laterally. Release of the lateral patellar retinaculum allows the patella to track correctly into the femoral groove.
3. Medial shift of the tibial tubercle : Moving the insertion of the quadriceps tendon medially at the tibial tubercle, allows the quadriceps to pull the patella more directly. It decreases also the amount of wear on the underside of the patella.
4.Removal of a portion of the patella
Physiotherapy of Chondromalacia Patellae
Conservative treatment of chondromalacia patellae is both physical and advisory.
Short-wave diathermy helps to relieve pain and increase the blood supply to the area, so improving the nutrition to the articular cartilage. Care must be taken when planning the exercise programme. ( level 3 )
The most common way to treat chondromalacia patellae is by strengthening the quadriceps muscle, because it has a very significant role in the movement of the patella.The best way to do this is with isometric quadriceps exercises and isotonic exercises in inner range. Isotonic quadriceps exercises through full range will only lead to increased pain and even joint effusion.(level3) Stretching of the vastus lateralis and strengthening of the vastus medialis is often recommended, but they are difficult to isolate because they have the same innervation and insertion.Therefore, it’s easier to strengthen the whole quadriceps.
Since the positioning and strength of the hip has a significant influence on anterior knee pain, training its strength and coordination is recommended. An increased hip adduction angle is associated with weakened hip abductors, so strengthening the hip abductors is advised. (Level 1A)
Many cases of chondromalacia patellae are self-limiting and treatment is primarily nonsurgical. Conservative therapeutic interventions include the following: ( level 5)
- Isometric quadriceps strengthening and stretching exercises – restoration of good quadriceps strength and function is an important factor in achieving good recovery.
- Hamstring stretching exercises
- Temporary modification of activity
- Patellar taping
- Foot orthoses
- Non-steroidal anti-inflammatory drugs
In this aspect of the therapy, make sure to give strength exercises, resistance exercises and coordination exercises of the quadriceps. Here is an example of an exercise program:
- Sit with the IL on a rolled towel under the fossa popliteum with no weight on the leg.
Extend the leg fast an relax slowly 50x
- stand on one leg (IL) with the knee slightly bent. Tap the foot of the HL in front, left, right and behind you on the floor
- Jumping: from left to right, from the back to the front, in a square and in a diamond.
By increasing the depth of a squat exercise progressively, the activity of the M. Gluteus Medius will increase. Thus, adding single-leg squats on a physioball to the program, lower extremity coordination and hip position in relation to the knee, may improve. Perform single-leg squats with a physioball between a wall and your back. the focus with this activity should be proper knee and hip positioning. (Level 1A)
- Manual perturbations applied against the hip musculature in side lying with one leg raised. (Level 1A)
- Performing a lunge with a twist. Perform a lunge while twisting your torso with your hands raised in front of you. (Level 1A)
- Extend the IL for 10 seconds.
- Strengthening the hip abductors begins with isometric exercises, performing prone heel squeezes will positively affect muscle recruitment of the hip abductors. (Level 1A)
- sit at the front of a chair with both legs extended just above the floor.
- Push the heel of the healthy leg(HL) against the heel of the injured leg(IL). Make sure there is no movement in both legs. Hold for 7 seconds.
- Sit with the IL on a rolled towel under the fossa popliteum,with a weight on the leg
- Stand with the IL, slightly bent, in front of the extended HL. Bend the IL
slowly. Make sure the knee never passes the foot. Move your weight to the IL. When you feel pain, quit immediately.
- stand with the IL on a step. Touch with the HL the floor by bending the
IL, first with the toes, then with the foot, then with the heel of the foot.
- Standing abduction with a resistance band. (Level 1A)
- Side-to-side walking with a resistance band. (Level 1A)
Not only do you have to strengthen the quadriceps, stretching is also important. And hereby you can also stretch the hamstrings and the iliotibial band. It is proven that patients with patellofemoral pain syndrome have shorter hamstrings than asymptomatic controls. Also are their hamstrings less flexible. It is recommended to stretch this tissues because it seems to improve the flexibility and knee function. Though it doesn’t improve pain or function by stretching alone. Including stretching in the therapy, in addition to active treatments, gives positive outcomes.
Ice & Drugs
Ice is sure to decrease pain, but is more frequently used to treat acute injuries. The efficacy of ice is questioned and the exact effect isn’t clear too. Therefore, more studies are required to create evidence based guidelines.
The benefit of anti-inflammatory drugs (NSAID’s) has not yet been proved. Although a lot of treatments for CMP aren’t proved either, the potential side effects of NSAID’s may be more severe than the side effects of ice and exercise. Therefore, a judicious trail may be worthwile.
Tapes and braces
Taping the patella into a certain position may be helpful, but the scientific evidence is varied. A commonly used technique is the ‘McConnell taping’. When taped properly, the McConnell tape may have a short-term pain relief.
Every form of supporting the patella and knee joint has proven that it can possibly reduce pain and symptoms but it is also possible it will change the tracking of the patella. Though it can be helpful because during the rehabilitation, patients will avoid certain movements to reduce the pain. This can cause a less functioning of the quadriceps. So using a brace or every form of support, that relieves the patient from pain, may aid in the recovery, as they will dare to use their quadriceps. This can be used for patients preoperatively as well as postoperatively. However there is suggested to use a brace which allows variation in the medial patellar pull and pressure.
Foot orthoses may be helpful in the pain relief of the knee, but only if the patient has signs of an excessive foot pronation, or a lower extremity alignment profile that includes excessive lower extremity internal rotation during weight bearing and increased Q-angle at the same time as he suffers from chondromalacia. When made properly, the orthotics will cause biomechanical changes (for example: a reduction in the Q-angle and internal rotation) in the lower leg by preventing overpronation in pes planus and providing a better support for normal feet and Pes cavus.