Osteochondrosis is a group of conditions in which the blood supply to growing bone is disrupted, causing patches of bone and cartilage to weaken, die, and sometimes break loose inside a joint. It primarily affects children and adolescents whose skeletons are still developing, and it can occur in the knee, hip, spine, foot, and other areas where bone grows through a process called endochondral ossification. Most cases respond well to rest and activity changes, though some require surgery.
How Osteochondrosis Develops
During childhood and adolescence, bones grow by converting cartilage into hard bone at specialized growth centers. This conversion depends on a steady blood supply delivered through tiny channels in the cartilage. When that blood supply is interrupted, the cartilage and underlying bone lose oxygen and nutrients, creating zones of dead tissue. These necrotic zones delay normal bone formation and can extend into the area just beneath the joint surface.
The core process across all forms of osteochondrosis follows the same three-phase pattern: tissue death from blood loss, followed by the body’s attempt to regrow blood vessels into the damaged area, followed by repair. How completely that repair happens, and whether it causes lasting problems, depends on the location, the size of the affected area, and the age of the patient.
Common Types and Where They Occur
Osteochondrosis isn’t a single diagnosis. It’s an umbrella term covering several named conditions, each defined by the bone it affects.
- Osteochondritis dissecans (OCD): Most often affects the knee, where a segment of bone and its overlying cartilage partially or fully separates from the joint surface. The medial femoral condyle (the inner knob at the bottom of the thighbone) accounts for about 64% of knee OCD lesions, with the lateral side making up roughly 33%.
- Legg-Calvé-Perthes disease: Affects the hip, specifically the ball-shaped top of the femur. A partial interruption of blood supply causes the bone to soften and sometimes collapse during the repair phase.
- Osgood-Schlatter disease: Affects the bony bump just below the knee (the tibial tubercle). Repeated pulling of the patellar tendon on this growth center during running and jumping causes inflammation and pain.
- Freiberg disease: Affects the second metatarsal head in the foot, likely from repetitive stress or disrupted blood flow. Improper footwear may contribute.
- Scheuermann disease: Affects the spine, causing excessive forward curvature (kyphosis). It’s diagnosed when X-rays show at least 5 degrees of anterior wedging in three or more adjacent vertebrae, with overall kyphosis exceeding 40 degrees.
Causes and Risk Factors
No single cause has been identified. The leading theory points to local blood supply problems in the growing cartilage, but several factors likely work together. Repetitive trauma from sports is a major contributor, especially in conditions like Osgood-Schlatter where the tendon repeatedly tugs on the growth plate. Genetic predisposition, hormonal imbalances, and mechanical factors such as joint alignment also play roles.
Boys are affected far more often than girls. In knee OCD, the male-to-female ratio is roughly 3.7 to 1. The condition is most common in adolescents ages 12 to 19, with an incidence of about 22 per 100,000 in that age group compared to about 9 per 100,000 in younger children. No cases have been found in children under 5.
Symptoms to Recognize
Symptoms vary depending on which bone is involved, but the most consistent sign is activity-related pain. In knee OCD, for example, pain typically flares when walking up stairs, climbing hills, or playing sports. Swelling and tenderness around the joint are common, and you may notice a feeling of weakness or the joint “giving way.”
If a piece of bone or cartilage has partially or fully separated, you might experience popping, catching, or the joint locking in one position as the loose fragment gets caught between the bones. Range of motion often decreases, making it hard to fully straighten the affected limb. In some cases, though, the damaged bone stays in place and causes few or no symptoms at all, with the condition discovered incidentally on imaging done for another reason.
How It’s Diagnosed
Diagnosis starts with X-rays, which can reveal the hallmarks of osteochondrosis: areas of bone destruction, irregular ossification, and sometimes visible loose fragments. The radiologic findings reflect the underlying cycle of bone death, attempted repair, and associated inflammation.
MRI is typically the next step because it provides a much more detailed picture. It can show the exact size of the lesion, whether the overlying cartilage is intact, and whether the fragment is stable or at risk of breaking free. These details are critical for deciding between conservative treatment and surgery.
Osteochondrosis vs. Osteochondritis Dissecans
These two terms are often used interchangeably, but they describe different things. Osteochondrosis refers to cartilage and bone damage caused by developmental blood supply problems. Osteochondritis dissecans specifically refers to a fragment that separates from the joint surface, often with a traumatic component. Under magnification, osteochondrosis lesions have smooth, elliptical borders with a gradual slope from edge to base. Osteochondritis lesions have rough, irregular edges where the surface has collapsed inward, more consistent with a fracture-like injury. In practice, osteochondritis dissecans can be thought of as a potential complication or advanced stage of osteochondrosis.
Treatment Without Surgery
For younger patients with stable lesions, the first approach is rest and protection. This typically means immobilizing the joint (with a brace or knee immobilizer for knee OCD) and limiting weight on the affected leg for four to six weeks. During this time, competitive sports are off limits.
Once pain resolves, you gradually increase weight-bearing and begin a rehabilitation program focused on range of motion and low-impact strengthening. If X-rays and symptoms show signs of healing at three to four months, a slow return to sports begins, with intensity increasing only as long as the joint stays pain-free. The overall timeline from diagnosis to full activity is often six months or longer.
When Surgery Is Needed
Surgery becomes necessary when the fragment is unstable or has detached, when symptoms include significant mechanical problems like locking, or when six months of conservative treatment hasn’t produced healing. Adults generally have a higher chance of needing surgery because their growth plates have closed, which limits the body’s natural repair capacity.
Surgical options depend on the fragment’s condition. If the piece is still partially attached and viable, surgeons can drill into the bone to stimulate blood flow and healing, then pin the fragment back in place. If the fragment is too damaged to save, it may need to be removed. This distinction matters for long-term outcomes: removing the fragment roughly doubles the risk of developing arthritis in that joint later, compared to procedures that preserve it.
Long-Term Outlook
Children and younger adolescents generally have the best prognosis because their bones are still actively growing and remodeling. Many juvenile cases heal fully with conservative care alone and cause no lasting joint problems.
The picture is more mixed for older adolescents and adults. A systematic review of knee OCD found that about 39% of patients eventually develop some degree of osteoarthritis in the affected joint. The biggest risk factors for arthritis were having a body mass index over 25 and having the fragment surgically removed rather than preserved. Larger lesions (bigger than 4 square centimeters) also carried a higher risk, roughly 2.3 times greater than smaller lesions. Interestingly, the patient’s sex, the exact location of the lesion within the knee, and whether it was treated surgically or not did not significantly affect arthritis risk on their own.
Maintaining a healthy weight and pursuing treatment strategies that preserve the fragment when possible are the two most actionable steps for reducing long-term joint damage.