Osteochondritis dissecans is a problem affecting bone beneath a joint surface and the overlying cartilage. In the knee it can cause activity-related pain, swelling, catching or locking. The important treatment question is whether the affected fragment is stable, not simply which injection to choose.
A careful assessment can distinguish a lesion that may be managed with protection and monitoring from one that needs specialist surgical advice. Ask about the right assessment before PRP, with existing scans and reports available. A clear diagnosis, explanation of the imaging and coordinated next steps are the foundation of a useful treatment plan.
What does the name mean?
Mayo Clinic describes osteochondritis dissecans as a condition in which part of the bone and cartilage can begin to break loose. It most often affects school-age children and teenagers, although adults can have persistent or previously unrecognised lesions.
The knee is a common site. The condition is different from simply having general wear-and-tear arthritis or a tendon problem around the knee. Similar symptoms can arise from different structures, so an online description cannot establish which is responsible for your pain.
Age and skeletal maturity matter. A lesion in a growing child may behave differently from one in an adult whose growth plates have closed. That difference helps determine whether protection, monitoring or a surgical pathway is most appropriate.
Which symptoms need attention?
Pain during sport, swelling after activity and reduced movement are reasons to seek assessment. Catching, locking or the feeling that something is moving inside the joint may indicate a mechanical problem, although they do not prove that a fragment is loose.
A knee that becomes genuinely locked, an inability to bear weight after injury or a hot swollen joint with fever needs urgent medical assessment. Do not use an injection enquiry as a substitute for the appropriate urgent pathway. Call 999 for a medical emergency.
For a child or teenager, ongoing pain or limping should be discussed with a clinician rather than repeatedly trained through. Pain that temporarily settles with rest does not establish that the underlying lesion has healed.
What can an examination and scan clarify?
The clinician asks about activity, injury, swelling and episodes of locking. Examination includes movement, tenderness and the way the joint functions. This helps decide what imaging is needed and how quickly specialist advice should be sought.
X-rays can show the bony lesion. MRI provides further information about cartilage, bone and possible instability, including when symptoms persist despite an apparently normal X-ray. CT may be used for selected questions about the bony fragment. Not everyone needs every scan.
Mayo's current guidance describes staging by size, whether the fragment is partly or fully detached and whether it remains in position. Ask what your report says about these features. The word lesion alone does not tell you what treatment is suitable.
How is treatment chosen?
The plan depends on symptoms, the lesion and whether the person is still growing. Early care may involve reducing impact, protecting the joint and a structured rehabilitation programme. Crutches or a brace may be recommended in individual cases.
A loose fragment, persistent symptoms or an unstable lesion may require an orthopaedic opinion. Surgical options are selected around the lesion rather than offered as one standard procedure for everyone. Rehabilitation and follow-up remain part of the pathway.
Do not set your own return-to-running date from another person's recovery. Pain relief and structural healing are different outcomes. The doctor needs to explain how progress will be checked and what is required before activity is increased.
What does current PRP evidence actually show?
A September 2026 systematic review examined orthobiologic injections used alongside cartilage-preserving surgery for focal knee cartilage defects. It included five randomised trials across different interventions. The authors concluded that evidence was insufficient to support these injections as stand-alone procedures.
That review does not show that an isolated PRP injection fixes osteochondritis dissecans, stabilises a loose fragment or replaces indicated surgery. Its surgical populations and varied protocols are important limits, not details to leave out when discussing potential treatment.
A treatment recommendation should explain which evidence applies to your specific diagnosis and which does not. Results from knee osteoarthritis cannot automatically be transferred to a focal bone-and-cartilage lesion. A biological rationale is a reason to research an approach, not proof of benefit for an individual patient.
What should I bring to a consultation?
Bring the actual imaging when possible, the written report, previous treatment details and a short account of what the knee prevents you doing. Note swelling, giving way and any true locking episodes. Include the dates and effects of earlier injections or surgery.
Arrange a diagnosis-led discussion if you want help identifying the appropriate next step. The suitable clinician, imaging needs, appointment route and complete fee should be confirmed before treatment is booked. An enquiry is not clinical clearance for an injection.
For an active professional or athlete, a useful plan should connect the diagnosis with daily function, work and sport. It should specify permitted activity, rehabilitation, review timing and the point at which another opinion is needed. This is more valuable than a treatment label without a recovery pathway.
Can I exercise while waiting?
Seek individual advice rather than forcing painful impact activity. The appropriate loading depends on stability and symptoms. A child with a limp or an adult with locking needs an assessment before assuming that normal training is safe.
Your next step
Treat the scan as the start of a decision, not a prescription for PRP. Ask for an assessment that explains stability and the next stage of care. Urgent symptoms should go to urgent services rather than wait for a routine reply.
Sources and evidence limits
Mayo Clinic: Osteochondritis dissecans diagnosis and treatment, updated May 2026. Staging, imaging and treatment pathways.
2026 systematic review of orthobiologics alongside cartilage-preserving surgery. Published abstract, not evidence for stand-alone PRP in every osteochondral disorder.
Prepared 3 November 2026. General patient information, not an individual diagnosis, activity clearance or treatment recommendation.