Disease Overview
Chondromalacia patellae is an osteoarthrosis of the patellofemoral joint in which the cartilage surface of the patella is swollen, cracked, broken, eroded, and
Finally, the cartilage of the femoral condyle opposite to it also undergoes the same pathological changes and forms the osteoarthrosis of the patellofemoral joint.
1, congenital abnormal patellar development.
2, long-term wear and tear of the knee joint, is the common cause of this disease.
3, abnormalities in the synovial fluid composition of the joint due to various causes. Symptoms: I. It is common in young athletes, initially pain under the patella, relieved after a little activity, then aggravated after too much exercise, and gradually disappears after rest. Second, pressure pain at the edge of the patella, squeezing or pushing the patella in the extended knee position can have a rubbing sensation, accompanied by pain. When patellofemoral joint osteoarthrosis is formed later, synovitis and joint effusion may occur. If the disease is of long duration, quadriceps atrophy may occur. The diagnosis of chondromalacia patella is mainly based on post-patellar pain, which is caused by the patellar compression and grinding test and the single-leg squat test. X-ray examination: frontal, lateral and tangential x-ray of the knee joint, no abnormalities in the early stage, but in the late stage, the gap between the patella and the femoral condyle may be narrowed due to extensive cartilage wear, and there may be osteophytes at the edge of the patella and femoral condyle. Treatment is mainly non-surgical: braking, physiotherapy, anti-inflammatory, patellar chondromalacia patch, joint cavity closure, etc. If strict non-surgical treatment is ineffective or there is congenital deformity, surgical treatment is feasible.
Patellar chondromalacia is an injury to the patellar cartilage that induces pain when flexing the knee, often obvious when going up and down stairs. Some patients also experience knee ringing, weakness and weakness of the knee joint due to pain. The pain worsens after walking long distances. However, not all people with these symptoms have chondromalacia patellae – chondromalacia patellae is a mild damage to the patella, a set of symptoms caused by the softening of the articular cartilage of the patella.
Disease classification
Orthopedics (Joint Surgery)
Disease Description
The patella is the largest hoe bone in the body, with the upper pole connected to the quadriceps tendon and the lower pole anchored to the tibial tuberosity by the patellar ligament. When the knee joint is flexed and extended, the patella slides in an “S” shape from near to far between the femur and the epicondyle. Chondromalacia patellae is an osteoarthrosis of the patellofemoral joint caused by chronic injury to the patellar surface, resulting in swelling, erosion, cracking, fragmentation, and loss of cartilage, and eventually the cartilage of the femoral condyle, which is opposite to the patellofemoral joint, also undergoes the same pathological changes.
Symptoms and signs
1, more common in young athletes. Initially, it is pain under the patella, which is obvious at the beginning of training and relieved after a little activity.
With the prolongation of the disease, the pain is more prolonged than relieved, resulting in the inability to squat, difficulty in going up and down the ladder or sudden weakness and fall.
2. pressure pain at the edge of the patella. When the patella is squeezed or pushed in the extended knee position, there is a feeling of friction and pain, and when the patellar cartilage is damaged, there is no joint effusion. If the disease is long, there is quadriceps atrophy.
3, the initial appearance of knee pain or with knee enlargement, should pay attention to rest, and appropriate exercise, mainly straight leg raising exercises, try to avoid weight-bearing knee flexion and extension activities. If there is reactive inflammatory thickening or spasm of the fat pad or soft tissue around the patella, physical therapy, herbal hot compresses or massage are feasible. The vast majority of patients with simple chondromalacia patella can be relieved with conservative treatment. If conservative treatment is ineffective and symptoms are worsening, surgical treatment should be considered. Normally, excessive squeezing and rubbing of the patellar surface should be avoided. For those who are over 50 years old and obese, repeated manipulation of the knee in a semi-flexed position should be avoided.
Clinical manifestations
Direct trauma to the knee can cause fractures of the patellar cartilage or osteochondral bone, or multiple injuries, such as sports injuries, can cause degenerative changes to the cartilage, with the cartilage surface becoming rough and losing its luster, or in severe cases, with the cartilage falling off and the bone being exposed, and the opposing femoral articular surface also being damaged. The injury site is mostly in the center of the patella. The main symptom is post-patellar pain in the knee joint, which varies in severity, but the pain increases after squatting and standing, going up and down stairs, going up and down slopes, or walking long distances.
Etiology of the disease
Basic theory
1, congenital patellar developmental disorders, abnormal position and femoral condyles large and small abnormalities, or acquired knee joint internal and external rotation deformity, etc., can make the patella unstable, in the process of sliding patellofemoral joint surface compressive stress concentrated in a certain point, become the basis of chronic injury.
2, long-term, forceful, rapid flexion and extension of the knee joint, increasing the wear and tear of the patellofemoral joint, such as the training of cyclists and skaters, is a common cause of this disease.
3, the patellar cartilage nutrition mainly from the synovial fluid, various causes of synovial fluid composition abnormalities, can make the patellar cartilage malnutrition, vulnerable to minor injuries and degenerative changes.
Trauma theory
Chondromalacia patella trauma, knee impact or acute dislocation of the patella can directly or indirectly cause damage to the patellar cartilage, causing chondromalacia of the patella. An animal model of chondromalacia of the patella caused by a blow to the rabbit patella has been produced. Qu Mianwei et al. found in the rabbit patellar cartilage friction experiment that the cartilage was significantly degenerated after 45h, with severe loss of chondroitin sulfate; and investigated 241 cases of athletes with chondromalacia patellae, with the result that up to 91% had a history of trauma.
Patellar instability
Patellar instability mainly refers to high patella, low patella, patellar tilt, patellar subluxation or dislocation. High patella refers to instability when the patellar ligament is too long causing the patella to slide. In normal knee flexion, the quadriceps muscle is in contact with the femoral condyles and the pressure on the patellofemoral joint surface is dispersed, while in high patella, the quadriceps muscle cannot be in contact with the femoral condyles at the same flexion angle, which increases the pressure on the patellofemoral joint surface, and high patella can also cause patellofemoral joint instability by impairing patellofemoral joint movement. Low patella refers to the patellar ligament being too short causing the patella to be too low. The Q angle is the angle between the quadriceps tendon and the patellar ligament extension line, which is normally less than 15°, and is considered abnormal if it is greater than 20°. The larger the Q angle, the greater the outward force on the patella, the more unstable the patella, and the more abnormal the distribution of patellofemoral joint pressure.
Increased intraosseous pressure in the patella
Intraosseous pressure is an important indicator of the state of blood circulation in the bone. The blood supply to the patella is mainly in the middle, inner 1/3 and apical patellar regions. As the peripatellar arterial ring and the prepatellar plexus (patellar network) are easily damaged during anterior knee soft tissue injury or knee overactivity, this affects the intrapatellar blood supply and venous return, resulting in intraosseous venous blockage and intraosseous hypertension. Hejgaard set the critical pressure of the patella at 30 mmHg.
Chondrolysis theory
Lack pointed out in 2007 that the osmotic pressure changes after synovial injury, plasma enzymes in the plasma can enter the synovial fluid more and their activity is increased, thus lysing the cartilage, causing the chondroitin sulfate content in the cartilage to increase and the cartilage to degenerate and lose elasticity.
Cartilage nutritional disorders
Patellar cartilage is a tissue without vascular nerves and lymphatic vessels, synovial fluid is a small amount, yellowish, clear liquid located in the joint cavity, there are about 1~2ml synovial fluid in the normal knee joint, the basic components of synovial fluid are plasma exudate, and hyaluronic acid, collagen and proteoglycan, when the joint activity, the cartilage is deformed by pressure, the extracellular fluid in the matrix is squeezed out, when the weight lifting pressure disappears The cartilage is restored by its elasticity, and the cartilage is thus nourished. On the contrary, if the pressure osmosis is lost, the articular cartilage does not get enough nutrition and degeneration occurs.
Autoimmune theory
The surface tissue of articular cartilage has the function of preventing anti-collagen antibodies from entering the deep cartilage tissue, which has a protective effect on the deep cartilage tissue. Antibodies against type II collagen were found in the joint fluid of patients with articular cartilage injury, and it was suggested that the pathological mechanism of synovitis after articular cartilage injury might be related to the autoimmune response to type II collagen, and that the pathological process of cartilage injury might involve the autoimmune response to type II collagen. We also examined the lesioned cartilage specimens of 12 patients with chondromalacia patellae by immunofluorescence histology, and found that immunoglobulin IgG, IgA, IgM and complement C3 were attached to the damaged areas of cartilage tissue and residual chondrocytes in all lesioned cartilage specimens, and concluded that the pathological process of lesioned cartilage injury caused by mechanical factors has autoimmune mechanism is involved.
The effect of patellofemoral pressure
Chondromalacia patella For many years, most scholars have emphasized the effect of exposure to high pressure on chondromalacia patellae, arguing that degeneration due to high stress first leads to the destruction of the cartilage matrix, resulting in the breakage of the collagen fiber meshwork and the loss of proteoglycans; matrix destruction causes changes in the normal microenvironment, leading to the degeneration of chondrocytes, and the early stage of cartilage matrix damage caused by high stress can cause some chondrocytes to proliferate and have an active The early stage of cartilage matrix damage caused by high stress can cause some chondrocytes to proliferate with active synthetic and secretory functions, but then most of them regress. However, it is difficult to explain the clinical phenomenon of chondromalacia in the medial aspect of the patella by the doctrine of excessive stress. This is because the medial lateral surface is the “non-habitual contact zone” of the patella, which only comes into contact when the knee is flexed above 120° and is rarely subjected to stress during normal times.
The mechanism of cartilage degeneration in a low-stress environment is different from that in a high-stress environment, as the medial patellar stress is reduced by tightening of the lateral patellar support band in rabbits, resulting in first degeneration of the deep chondrocytes and then degeneration of the surrounding matrix. Gu Yan found that a proper stress environment is very important to maintain the integrity of articular cartilage, and the lack of sufficient stress prevents the cartilage from being effectively nourished even if joint movement is preserved, thus leading to cartilage degeneration. In recent years uneven pressure distribution in the patellofemoral joint has received attention, and it is believed that stress imbalance is the cause of cartilage degeneration.
Pathophysiology
Patellofemoral cartilage chondromalacia is an osteoarthrosis of the patellofemoral joint caused by chronic injury to the patellar surface, resulting in swelling, erosion, cracking, fragmentation, and loss of cartilage, and eventually the same pathological changes occur in the cartilage of the femoral condyle opposite to it.
Diagnostic tests
1, no abnormalities in the early stage of X-ray film, late stage can be seen in the patellar semicircular bone superfluity affect the patellofemoral joint surface is not smooth or gap narrowing, X-ray film can still find part of the cause, such as small patella, high patella or femoral epicondyle low level deformity.
2, radionuclide bone imaging examination, the lateral position shows the limited radioactive concentration of patella, has early diagnostic significance.
Arthroscopy (both diagnostic and therapeutic)
Arthroscopy is the most visual method to confirm the diagnosis of chondromalacia patellae. It can clarify whether there is a lesion in the articular cartilage and the extent of involvement, and the degree of patellar chondromalacia, and is better differentiated from diseases characterized by anterior knee pain, especially in difficult patients.
Magnetic resonance imaging (MRI) is also useful for early diagnosis.
Treatment options
For milder symptoms of chondromalacia patella, it is important to avoid direct impact on the patella and reduce patellar friction activities, such as walking up and down hills, stairs and bicycles, to reduce symptoms. Surgical treatment for more severe symptoms should be timely surgery, according to the patella lesion for appropriate treatment.
1, after symptoms appear, first brake the knee joint for 1-2 weeks, and at the same time perform resistance exercises for the quadriceps muscle to increase the stability of the knee joint.
2. When the swelling and pain suddenly increase, cold compresses should be applied, and after 48 hours, wet heat compresses and physical therapy should be used instead.
3.Anti-inflammatory drug “Aminoglycoside” contains glucosamine, which helps synthesis of protein mucopolysaccharide in cartilage. 0.2-0.4g orally, twice daily, can not only relieve pain, but also help cartilage repair.
4, intra-articular injection of sodium vitreous acid (sodium hyaluronate) can be responsible for the viscosity and lubricating function of joint fluid, protect joint cartilage, promote the healing and regeneration of joint cartilage, relieve pain and increase joint mobility. Usually 2ml per injection, once a week, 4-5 times as a course of treatment.
5, intra-articular injection of prednisolone acetate can relieve symptoms, but it should be used with caution because it inhibits the synthesis of glycoprotein and collagen, which is detrimental to cartilage repair.
6.Strictly non-manipulative treatment is ineffective, or those with congenital deformity can be treated surgically.
Surgical treatment
Tibial tuberosity elevation has been recognized as a more ideal treatment for chondromalacia patellae, with an excellent rate of up to 86%. Zhang Weiguo et al. used modified tibial tuberosity elevation to treat 30 cases of chondromalacia patellae with good results. The treatment of patellofemoral arthritis with tibial tuberosity lift and subchondral bone drilling was satisfactory.
The total effective rate was 639% at 1a and 457% at 5a. McKeever first reported artificial patellar surface replacement in 1955. The treatment of advanced chondromalacia patellae with artificial patellofemoral surface replacement is satisfactory. Suture muscle advancement was used to treat chondromalacia patella with good results. Drilling therapy was used to treat chondromalacia patella with a total effective rate of 838%. Seventeen cases of chondromalacia patella were treated with periosteal graft plus sodium hyaluronate with satisfactory results. Arthroscopically assisted percutaneous lateral patellar support band release was applied to treat chondromalacia patellae, with an excellent rate of 857%. Arthroscopic radiofrequency vaporization combined with peripatellar drilling and decompression was applied to treat chondromalacia patella in 56 cases, with good results.
In recent years, research on tissue engineering, cytokines and gene therapy has provided new ideas and methods for the treatment of chondromalacia patellae. Kim used degradable polymorphic material PLGA, made into various shapes as desired, and implanted fresh chondrocytes on the scaffold material for 1 week in vitro and then transplanted into the body to form hyaline cartilage tissue. Although cytokine and gene therapy are still in clinical trials, preliminary studies have shown their effectiveness and reliability in the treatment of cartilage lesions. With further research, they will certainly become important therapeutic tools. Surgical objectives.
(1) To increase the stability of the patellofemoral joint during its movement, such as lateral capsulotomy and femoral epicondyle padding.
(2) To scrape away smaller eroded lesions on the patellofemoral articular cartilage to promote repair.
(3) For those whose patellofemoral articular cartilage has been completely destroyed, patellar resection is useful to reduce the development of patellofemoral osteoarthropathy, but the knee joint is obviously weak after surgery, making it difficult to continue its athletic career.
Patellofemoral cartilage cutting includes superficial cartilage cutting, cartilage cutting to bone and bone drilling.
Superficial cartilage cutting A sharp knife is used to cut the degenerated cartilage down to the normal part of the cartilage. Although the cartilage repair ability is very weak after superficial cutting, the surface is smoothed and covered with several layers of flattened cells after several months of shaping by removing the eroded cartilage, so that the operation can achieve more satisfactory results.
Cartilage cutting to the bone If the cartilage damage has reached the bone, the whole cartilage can be cut and the edges of the wound can be trimmed to make a beveled surface, leaving the exposed bone untreated. Full cartilage defects that do not reach the medullary cavity can be regenerated slowly and endogenously, and the regenerated cartilage is hyaline cartilage.
Cartilage cutting to the bone and drilling The diseased full cartilage is cut away and the exposed bone is drilled with several holes using a kerf needle to cause bleeding in the bone bed. A full defect of articular cartilage deep to the medullary cavity can be repaired exogenously with mesenchymal tissue from the medullary cavity. The above procedure can be done arthroscopically, with a planer cut, or under direct vision with an arthrotomy.
Patellofemoral osteoplasty After cutting away the diseased cartilage, if the bone is exposed (2-3 cm), the exposed bone surface can be covered with adjacent synovial membrane or by cutting a layer of fat pad and flipping the suture.
Cartilage regeneration treatment
Cartilage regeneration treatment focuses on repairing cartilage from the inside, and thus repairing the patella, and is therefore generally welcomed. According to the information on health prescriptions issued by the Chinese Health Education Center under the Ministry of Health, there are currently three directions for cartilage regeneration. a laboratory chondrocyte cultivation method, b ingestion of natural sawtooth shark cartilage powder to promote the regeneration of one’s own cartilage, and c surgical correction to promote internal cartilage repair. Of these, a and c are still in the scientific research stage, while b is already in clinical popularity. Since the patella is a large piece of cartilage, if cartilage regeneration is achieved, it also means the elimination of chondromalacia patellae and therefore becomes the goal of international cutting-edge medical efforts [1].
Daily attention points
1. Move the joint before exercise
Fully moving the joint before exercise can stimulate all parts of the patellofemoral articular surface, and the synovial fluid nutrients can evenly penetrate into the cartilage tissue to enhance the lubrication of the joint.
2, avoid strenuous exercise
Avoid continuous squatting and strenuous exercise, such as climbing mountains, stairs and other knee flexion exercise. Avoid sudden changes in the intensity of exercise, and activities to increase strength and endurance should be gradual and increase gradually.
3. Maintain proper body weight
Appropriate weight can reduce the gravitational force on the knee joint, while obesity will increase the risk of degenerative diseases of the knee joint, forming a vicious circle, the greater the weight, the heavier the pain; conversely, the lighter the weight, the lighter the pain.
4.Supplement cartilage nutrition
Eat more food containing vitamins and proteins, such as fruits, vegetables, meat, seafood, etc.
5.Pay attention to keep warm and cold
During the cold season, keep the joints warm to prevent wind and cold invasion.
6, timely treatment
When there is discomfort or unlocalized pain in the knee joint, consider the possibility of early patellar chondromalacia, rest and treatment in time to prevent aggravation of joint cartilage degeneration.
7, pay attention to warmth and cold weather season, to keep the joints warm, to prevent wind and cold invasion.
Disease prevention
Avoid long-term, forceful, rapid flexion and extension movements. The occurrence of chondromalacia patella has both intrinsic and extrinsic factors for middle-aged and elderly people. The intrinsic factor is the degeneration of the articular cartilage itself, which is related to age and other factors. The extrinsic factor is the chronic damage to the articular cartilage caused by mechanical factors. Prevention of chondromalacia patellae is mainly from reducing the continuous pressure on the patellofemoral joint and improving the nutrition of the cartilage.
1, active full joint movement. To be carried out under non-weight-bearing conditions. Such as lying in bed actively extend and flex the knee joint. Insist on 10 minutes once a day, once in the morning and once in the evening. Adequate movement of the joint can make all parts of the patellofemoral joint surface are stimulated, synovial fluid nutrients can evenly penetrate into the cartilage tissue, and can enhance the lubrication of the joint.
2, to prevent continuous pressure on the patellofemoral articular surface. The patella is under greater pressure in the flexed knee position, which can easily damage the joint surface. To avoid continuous squatting pressure on the patellofemoral articular surface.
3, cast fixation or lower limb traction treatment. When the quadriceps muscle is contracted, it can drive the patella up and down, which is conducive to the nutritional penetration of the cartilage and reduces the continuous pressure on the patellofemoral articular surface.
4, when the knee joint discomfort or non-localized pain. To consider the possibility of early patellar chondromalacia, timely rest and timely treatment should be provided to prevent aggravation of articular cartilage degeneration.
Medication safety
1, in the early stage of the lesion, the amount of knee joint activity should be reduced and protected with bandages or lightweight braces. If the symptoms persist for several months and cannot be relieved and affect work or life, surgery may be considered.
2. Strengthen joint protection. If you want to exercise, you should wear a knee brace, and do not overload, from small to large, uniform speed to save effort. Rest and hydrate properly on the way.
3. For people who have knee problems, it is not advisable to climb steep hills or go up and down large steps.