Osteochondritis dessicans
Osteochondritis dissecans occurs when a fragment of bone in a joint separates from the rest of the bone because its blood supply is faulty, and there is not enough blood to maintain it.
It often affects the knee, ankle or the elbow.
Sometimes, the separated fragment stays in place or repairs on its own. However, in the later stages, the bone can splinter and fall into the joint space, resulting in pain and dysfunction. These fragments are sometimes called "joint mice."
The exact prevalence is unknown, but there may be between 15 and 29 cases in every 100,000 people. It is more common in males, especially those between the ages of 10 and 20 years who are physically active.
However, the incidence is increasing in females.
It usually affects teens and young adults, but it can occur in younger children who are active in sports.
Signs and symptoms
Osteochondritis dissecans (OCD) can occur in different joints, including the hip and ankle, but 75 percent of cases affect the knee.
Signs and symptoms of OCD include:
inflammation, swelling, and soreness in the joint
catching and locking in the joint during movement
reduced range of movement in the joint
crepitus, a grating, cracking, or popping sound when moving the joint
weakness in the joint
limping
effusion, or abnormal collection of fluid in the joint area, leading to swelling
pain, especially after physical activity
stiffness after a period of inactivity
Causes
The exact cause is unknown, but they may include:
Ischemia: a restriction of blood supply starves the bone of essential nutrients. The restricted blood supply is usually caused by some problem with blood vessels, or vascular problems. The bone undergoes avascular necrosis, a deterioration caused by lack of blood supply. Ischemia usually occurs in conjunction with a history of trauma.
Genetic factors: OCD sometimes affects more than one family member. This may indicate an inherited genetic susceptibility.
Repeated stress to the bone or joint: this can significantly increase the risk of developing OCD. Individuals who play competitive sports are more likely to regularly stress their joints.
Other factors may be weak ligaments or meniscal lesions in the knee.
Diagnosis
A person who experiences the symptoms of OCD in a joint should seek medical advice. An early diagnosis can mean more effective treatment and a lower risk of complications.
The doctor will carry out a physical examination and ask the patient about their medical history, family history and lifestyle, including sporting activities.
There may be some imaging tests, such as an X-ray, CT, MRI scan, or ultrasound. This may show whether there is any necrosis, or tissue death, or loose fragments. A bone scan may also be recommended.
In the early stages, tests will show that the cartilage is thickening. In the later stages, there will be loose fragments.
The early stages are considered stable, and treatment is more likely to be effective at this point.
Conditions, with similar symptoms need to be ruled out. These include inflammatory arthritis, osteoarthritis, bone cysts and septic arthritis.
Treatment
Conservative measures include changes of activity or rest.
This can give the bone time to heal and to prevent future fracture, crater formation, or chondral (cartilage) collapse.
If the patient has been involved in sports, they may need to stop for a while.
The doctor may immobilize the joint with a medical device, such as a splint or a brace. Crutches may be necessary.
A non-steroidal anti-inflammatory medication (NSAID) can help with pain. A physical therapist may offer guidance with stretching and specific exercises.
Children can normally return to sports after 2 to 4 months. In young children, OCD normally heals with rest, as the bones are still growing.
In older children and adults, the effects can be more severe.
Surgery
Surgery aims to:
restore normal bloodflow
get the joint to work normally again
It may be recommended if conservative measures have not worked, if a lesion has become detached and is moving around inside the joint, or if the lesion is over 1 centimeter in diameter.
Drilling into the lesion can create pathways for new blood vessels to form in. This allows blood to flow, and encourages the bone to heal.
The surgeon makes a small incision. Using some long, thin instruments, they either remove or reattach the loose fragments of bone. If the cartilage is still attached to the bone, pins or screws can be used to secure it.
Osteochondral autograft transfer (OATS) uses healthy cartilage to replace damaged cartilage on the surface of the joint that receives weight-bearing stress. It is like a cartilage transplant, but the recipient and donor is the same person.
After surgery the patient will undergo a rehabilitation program. After an initial period of immobilization, physical therapy can help regain joint strength and stability.
According to the American Academy of Orthopedic Surgeons (AAOS), the patient will probably need:
crutches for about 6 weeks after surgery
physical therapy for 2 to 4 months, to recover strength and motion
After 4 to 5 months, a gradual return to sports may be possible.
Minimally invasive arthroscopic surgery is less painful, the recovery time is faster, and the risk of complications is lower.
Complications
Without treatment, complications may occur. These include pain, functional impairment, recurrent swelling of the joint, and the formation of loose fragments.
Around 5 percent of middle-aged patients with osteoarthritis experienced OCD at a younger age.
https://patient.info/doctor/osteochondritis-dissecans Sagittal MRI: Linear low T1 signal at the articular surfaces of the lateral aspects of the medial condyle of the femur confirms the presence of OCD.
Treatment
Treatment options include modified activity with or without weight bearing;
immobilization; cryotherapy; anti-inflammatory medication; drilling of subchondral bone;
microfracture; removal or reattachment of loose bodies; mosaicplasty and osteoarticular transfer system (OATS) procedures.[29][50] The primary goals of treatment are:[51]
Enhance the healing potential of subchondral bone;
Fix unstable fragments while maintaining joint congruity; and
Replace damaged bone and cartilage with implanted tissues or cells that can grow cartilage.
The articular cartilage's capacity for repair is limited:[52] partial-thickness defects in the articular cartilage do not heal spontaneously, and injuries of the articular cartilage which fail to penetrate subchondral bone tend to lead to deterioration of the articular surface.[53] As a result, surgery is often required in even moderate cases where the osteochondral fragment has not detached from the bone (Anderson Stage II, III).[54]
Non-surgical treatment
Candidates for non-operative treatment are limited to skeletally immature teenagers with a relatively small, intact lesion and the absence of loose bodies.
Non-operative management may include activity modification, protected weight bearing (partial or non-weight bearing), and immobilization.
The goal of non-operative intervention is to promote healing in the subchondral bone and prevent potential chondral collapse, subsequent fracture, and crater formation.[51]
Once candidates for treatment have been screened, treatment proceeds according to the lesion's location. For example, those with OCD of the knee are immobilized for four to six weeks in extensionto remove shear stress from the involved area;[55] however, they are permitted to walk with weight bearing as tolerated.
X-rays are usually taken three months after the start of non-operative therapy; if they reveal that the lesion has healed, a gradual return to activities is instituted.[54][56]
Those demonstrating healing by increased radiodensity in the subchondral region, or those whose lesions are unchanged, are candidates to repeat the above described three-month protocol until healing is noted.[36]
Surgical treatment
The choice of surgical versus non-surgical treatments for osteochondritis dissecans is controversial.[57] Consequently, the type and extent of surgery necessary varies based on patient age, severity of the lesion, and personal bias of the treating surgeon—entailing an exhaustive list of suggested treatments. A variety of surgical options exist for the treatment of persistently symptomatic, intact, partially detached, and completely detached OCD lesions. Post-surgery reparative cartilage is inferior to healthy hyaline cartilage in glycosaminoglycan concentration, histological, and immunohistochemical appearance.[58]As a result, surgery is often avoided if non-operative treatment is viable.
Intact lesions
If non-surgical measures are unsuccessful, drilling may be considered to stimulate healing of the subchondral bone. Arthroscopic drilling may be performed by using an antegrade (from the front) approach from the joint space through the articular cartilage, or by using a retrograde (from behind) approach through the bone outside of the joint to avoid penetration of the articular cartilage. This has proven successful with positive results at one-year follow-up with antegrade drilling in nine out of eleven teenagers with the juvenile form of OCD,[59] and in 18 of 20 skeletally immature people (follow-up of five years) who had failed prior conservative programs.[60]
Arthroscopic image of OATS surgery on the medial femoral condyle of the knee
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Full thickness lesions
Morselization of the articular cartilage lesion
The three methods most commonly used in treating full thickness lesions are arthroscopic drilling, abrasion, and microfracturing.In 1946, Magnusson established the use of stem cells from bone marrow with the first surgical debridement of an OCD lesion. These cells typically differentiate into fibrocartilage and rarely form hyaline cartilage. While small lesions can be resurfaced using this form of surgery, the repair tissue tends to have less strength than normal hyaline cartilage and must be protected for 6 to 12 months. Results for large lesions tend to diminish over time; this can be attributed to the decreased resilience and poor wear characteristics of the fibrocartilage.[63]In attempts to address the weaker structure of the reparative fibrocartilage, new techniques have been designed to fill the defect with tissue that more closely simulates normal hyaline articular cartilage. One such technique is autologous chondrocyte implantation (ACI), which is useful for large, isolated femoraldefects in younger people. In this surgery, chondrocytes are arthroscopically extracted from the intercondylar notch of the articular surface. The chondrocytes are grown and injected into the defect under a periosteal patch. ACI surgery has reported good to excellent results for reduced swelling, pain and locking in clinical follow-up examinations.[64][65] However, some physicians have preferred to use undifferentiated pluripotential cells, such as periosteal cells and bone marrow stem cells, as opposed to chondrocytes. These too have demonstrated the ability to regenerate both the cartilage and the underlying subchondral bone.[66]Another method used to promote normal articular cartilage replacement is the technique of transplanting autologous osteochondral plugs. The autografts are taken from a relatively non-weight-bearing region of the knee, such as the area just above the intercondylar notch or the edge of the patellar groove, and inserted in the defect. OATS has reported good clinical results with plugs taken from the lateral facet of the patella when treating ten cases with large femoral OCD lesions.[67][68] OATS is limited by donor site morbidity, plug damage from insertion, and the challenge of placing the plug edges flush with adjacent cartilage.[69] Fresh osteocartilaginous allografts have also been used for the treatment of OCD defects. In a study of 126 people with OCD of the knee, Ghazavi et al. reported an 85% success rate 7.5 years after OATS surgery with allografts. This procedure may be an option when other treatments have failed and symptoms persist.[70]Similar to OATS, arthroscopic articular cartilage paste grafting is a relatively new surgical procedure offering cost-effective, long-lasting results for stage IV lesions. An osteocartilaginous paste derived from crushed plugs of the non-weight-bearing intercondylar notch can achieve pain relief, repair damaged tissue, and restore function.[71]
Hyaline articular cartilage is a firm and durable tissue. Cartilage covers the ends of bones in joints and enables the bones to move smoothly over one another. Therefore, healthy cartilage is crucial to the smooth and painless mobility of most joints, including the knee.
Cartilage damage can be caused by athletic activity, traumatic injury, and even daily wear and tear. Injuries to the articular cartilage of the knee can take the form of lesions, which are like potholes in the cartilage. Symptoms of an injury can include aching, pain, swelling, locking, catching and giving way.
Damaged cartilage has limited capacity to repair or restore itself. If untreated, the damage may progressively worsen and may lead to chronic conditions such as osteoarthritis.
[
Impacting the paste graft into the morselized defect
Manual crushing used to make a paste graft
Harvesting of the articular cartilage and bone
Current treatment options are limited and vary depending on individual patient factors and surgeon preference.
Despite the availability of a range of procedures and treatments, patients are often left searching for new options due to incomplete recovery or limited duration of effect. Microfracture is commonly performed and is considered the current standard of care for most cases of severe cartilage injury in the knee. Microfracture works by creating tiny holes, or “fractures,” in the bone underneath the injured cartilage, leading to formation of a blood clot in the affected area. The blood and bone marrow that seep out to form the clot contain stem cells, which are thought to grow into cartilage-building cells. Although symptoms may improve for a period of time after the surgery, microfracture has been unsuccessful in reliably solving the underlying problem of the injured cartilage. In most cases, the repair tissue formed by the procedure is not the same healthy joint cartilage that joints require to withstand the normal forces of movement and weightbearing.
Made from a patient’s own cells, an investigational cartilage tissue implant to treat knee cartilage injuries.