Patellar chondromalacia is a degenerative destruction of cartilage located on the posterior surface of the patella. It is manifested by pain during movements, prolonged stay in a position with bent knees. It is diagnosed on the basis of complaints, physical examination data and the results of non-invasive imaging studies. Sometimes arthroscopy is performed. Therapeutic measures include correction of the regime of motor activity, physical therapy, physiotherapy, drug therapy. In case of inefficiency, arthroscopic surgical intervention is indicated.
M22.4 Patellar chondromalacia
Patellar chondromalacia (chondro – cartilage, malakia – softness) – softening of the cartilage of the articular surface of the bone. It is a widespread pathology, accounting for 9.5-19.4% of the total number of degenerative diseases of the knee joint. Mostly active young people suffer. Women get sick more often than men, which is explained by differences in the anatomical structure of the lower extremities. With a long course, there is a frequent combination with gonarthrosis. Some experts consider chondromalacia as an early manifestation of arthrosis.
Modern researchers believe that patellar chondromalacia is a polyethological pathology. At the heart of the disease are constant overloads of the patella with impaired cartilage nutrition. The etiological factors include:
- Anatomical features. The risk of the disease increases with congenital underdevelopment of the articular surfaces of the patella and femur, to which it adheres with its posterior surface.
- Traumatic injuries. Chondromalacia can form in people who have suffered a direct injury (fracture of the patella, severe bruising with cartilage damage), dislocation of the patella or rupture of ligaments.
- Repeated microtrauma. An ill-conceived load, usually when doing sports (running, jumping, lifting weights) leads to minor repeated injuries of the cartilaginous tissue of the patella.
- Muscle imbalance. As a result of weakness of the quadriceps muscle or an imbalance between the muscles of the outer and inner surface of the thigh, patellar instability occurs, increasing the likelihood of microtrauma.
- Tendon diseases. With tendinitis and tendinosis of the quadriceps, there is a redistribution of the load on the lower limb, which also leads to the formation of instability of the patella.
Obesity is a significant provoking factor. A certain role is assigned to metabolic disorders and endocrine pathologies. Previous inflammatory diseases of the joint are important. The importance of the size of the angle between the quadriceps and the femur is noted – normally this angle is larger in women, which causes a higher probability of the disease, but there are anatomical variations.
Due to nutritional disorders, local damage to cartilage tissue is formed in the places of the greatest load. Areas of cystic rearrangement appear, sclerotic changes occur. During the breakdown of cartilage cells, metabolites are formed that enter the synovial fluid, causing reactive inflammation. The cartilage is thinned, covered with cracks, the underlying subchondral bone is exposed. At the final stage of the disease, the cartilage is almost completely absent, the bone undergoes degenerative changes.
Taking into account the changes detected by the use of non-invasive imaging techniques, arthroscopy and morphological examination of cartilage tissue, specialists in the field of orthopedics and traumatology distinguish four degrees of severity of patellar chondromalacia:
- 1. Visual examination determines minor focal changes. When examining a tissue sample, areas of edema and softening of cartilage are detected.
- 2nd. Small defects are visible. The cartilage is fibrous, fragmented. Erosions and cracks extend deeper into less than half the thickness of the cartilage tissue.
- 3rd. The cartilage is thinned, deep defects are visible. Fragmentation and dislocation of cartilage are aggravated. The depth of cracks and erosions is more than half the thickness of the cartilage layer up to the underlying bone.
- 4th. Cartilage tissue is absent for a considerable length, the subchondral bone is exposed, degeneratively altered.
The disease develops gradually. The first signs, as a rule, occur in adolescence or at a young age. Patients are concerned about aching pains that are localized in depth along the anterior surface of the knee or are of a shingling nature. Pain syndrome appears without a previous injury, less often develops some time after a traumatic injury.
At first, pain is noted only with intense stress on the knee or with prolonged stay in a stationary position (for example, sitting with legs bent at an angle of 90 degrees, during lectures, at work, when attending a performance). Subsequently, pain sensations appear with minor loads, for example, walking on the stairs. Soreness is most pronounced with strong flexion of the joint, for example, when trying to sit down deeply.
Some patients report feeling discomfort or instability in the joint. Sometimes complaints are extremely vague and do not allow to establish the localization of pathology. On examination, atrophy of the quadriceps muscle is determined in a number of patients, usually not clearly expressed. Fluid may be detected in the joint. Crepitation is possible during movements.
The most common complication is recurrent synovitis. With the long-term existence of the disease, deforming arthrosis of the patellar-femoral joint develops. Data on the relationship between patellar chondromalacia and gonarthrosis are ambiguous, but many experts believe that these diseases are etiologically and pathogenetically related.
The diagnosis is made by an orthopedic traumatologist. The diagnostic process uses complaints, life history and disease data (the presence of risk factors, previous injuries and conditions that can lead to patellar chondromalacia) and the results of additional studies. The survey plan includes the following activities:
- External inspection. It provides for the study of the anatomical features of the structure of the lower limb (in particular, the determination of the angle between the femur and the quadriceps tendon), the condition and tone of the muscles, the assessment of the consistency of the ligamentous apparatus.
- Palpation of the joint. During palpation, an effusion in the joint is sometimes determined. Using special techniques (pressing the patella), the points of maximum soreness are set. A patellar displacement test is performed to detect instability.
- Knee joint x-ray. With chondromalacia, the technique is not informative enough, in a number of patients it confirms a violation of the position of the patella. It is prescribed to detect developmental abnormalities, the consequences of injuries, signs of arthrosis.
- CT of the knee joint. Computed tomography makes it possible to determine at what point of movement pathological symptoms occur. Cystic rearrangement is found on the sections, in severe cases – damage to the subchondral bone.
- MRI of the knee joint. Visualizes pathological changes in cartilage. Allows you to confirm the change in the structure of cartilage tissue and thinning of the cartilage layer, to determine the presence of defects and their depth.
- Arthroscopy. It is rarely produced, usually it is of a therapeutic and diagnostic nature. It is used to assess the severity of pathological changes and exclude other causes of pain.
With similar clinical symptoms, differential diagnosis of chondromalacia with arthrosis may be required. Patients suffering from arthrosis usually belong to the older age group, osteophytes and narrowing of the articular gap are found on X-rays. Sometimes differentiation is carried out with prepatellar bursitis, rupture of the medial meniscus, dissecting osteochondritis and fat cushion syndrome.
Treatment is usually conservative, performed on an outpatient basis, includes medication and non-drug therapy. Surgical interventions are rarely performed, they are required in advanced cases of the disease.
It is indicated in the early stages of patellar chondromalacia, it is carried out for a long time (for several months). The following therapeutic measures are carried out:
- Protective mode. The patient is recommended to limit the load on the knee joint. It is necessary to exclude movements that can cause microtrauma of the cartilage, for example, forced deep flexion of the limb. It is undesirable to run, perform actions with an emphasis on knees, walking on stairs.
- Joint fixation. Immobilization with a plaster cast is not recommended, as this can worsen the atrophy of the quadriceps muscle and cause limited movement in the joint. While walking, you can apply an elastic bandage or fix the knee with a bandage.
- Physical therapy. A special program includes exercises to correct the imbalance of the muscle groups of the thigh and lower leg. Static exercises to strengthen the quadriceps occupy a special place in terms of physical therapy.
- Drug therapy. Taking salicylic acid derivatives for 3-4 months in some cases helps to eliminate the softening of cartilage tissue at the initial stage of the disease. Intra-articular administration of chondroprotectors is possible. Glucocorticoids are not indicated due to the absence of intense pain and the risk of worsening cartilage degeneration.
In most cases, these measures are sufficient to eliminate the symptoms. With the preservation of pain syndrome, crunch and effusion in the joint, surgical intervention is required.
Operations are performed using arthroscopic equipment. The purpose of the interventions is to correct the position of the patella or stimulate the regeneration of cartilage tissue. Can be performed:
- Arthroscopic lavage. Provides rapid restoration of joint functions by eliminating mechanical obstacles to movement and removing the decay products of tissues that support inflammation. Effective in the initial stages of the disease. In the final stages, it is not recommended due to the short duration of the therapeutic effect.
- Mobilization of the patella. Mobilization of the outer edge of the patella is carried out with an obvious inclination of the bone. The operation can be performed immediately after arthroscopic lavage. Like the previous intervention, it is effective at the initial stage of chondromalacia.
- Abrasive chondroplasty. During abrasive chondroplasty, damaged areas of cartilage are removed, stem cells are injected into the tissue, which stimulate regeneration. It is indicated with moderate destruction of cartilage.
- Mosaic chondroplasty. It provides for the replacement of defects with small bone-cartilage grafts. It is used in the II and III stages of chondromalacia.
In the postoperative period, rehabilitation measures are prescribed. At the IV stage of chondromalacia and with severe gonarthrosis, these surgical methods are ineffective or contraindicated. With severe joint dysfunction, intense pain syndrome, patellectomy or patellar contouring is possible.
In patients with early stages of patellar chondromalacia, the prognosis is favorable. Complete restoration of cartilage tissue or a significant slowdown in the progression of the pathological process is possible. The ability to work is fully preserved. A number of patients manage to return to active sports (including professionally). With significant destruction of cartilage, it is possible to limit the function of the joint.
Preventive measures include injury prevention, a well-thought-out training regime to avoid overloads and microtraumas of the knee joint. It is necessary to identify and treat gonitis of various etiologies, tendinosis and tendinitis of the quadriceps tendon in a timely manner.
- Chondromalacia Patella. Habusta SF, Coffey R, Ponnarasu S, Mabrouk A, Griffin EE. 2022 Nov 17. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan link
- An experimental study on the etiology of chondromalacia patellae. Funakoshi T. Nihon Ika Daigaku Zasshi. 1991 Aug;58(4):29-39. link
- MRI quantitative morphologic analysis of patellofemoral region: lack of correlation with chondromalacia patellae at surgery. Endo Y, Schweitzer ME, Bordalo-Rodrigues M, Rokito AS, Babb JS. AJR Am J Roentgenol. 2007 Nov;189(5):1165-8. link
- Assessment of the relationship between patellar volume and chondromalacia patellae using knee magnetic resonance imaging. Sirik M, Uludag A. North Clin Istanb. 2019 Oct 10;7(3):280-283. link
- Historical perspectives of chondromalacia patellae. Kelly MA, Insall JN. Orthop Clin North Am. 1992 Oct;23(4):517-21. link