This is a 1:1 randomised pilot study in 30 patients in 1 site in Helsinki, Finland.

The investigators hypothesize that function, pain, type and quality of cartilage in adult patients with osteochondritis dissecans of the knee will be better in the DBX group compared to the mosaicplasty group.

Inclusion Criteria:

• Males or females, age between 18 years and 65 years

• Females of childbearing potential must have a negative serum or urine pregnancy test at the time of inclusion

• Females of childbearing potential must be willing to use effective means of birth control for at least 1 year post surgery. Medically acceptable contraceptives include:

  1. Surgical sterilisation
  2. Approved hormonal contraceptives
  3. Barriers methods combined with a spermicide
  4. An intrauterine device
  5. Abstinence alone is not considered an acceptable method of contraception

• Late stage Osteochondritis Dissecans (ICD-10 code M93.2) of the knee classified as stage III or IV (Anderson MRI classification)

• Mature skeleton

• Written informed consent prior to any study specific procedures (except the procedures necessary to determine eligibility)

• Ability and willingness to comply with all study specific procedures, including attending all follow-up visits up to 12 months postoperative and completing questionnaires in a local language

Exclusion Criteria:

• More than 1 knee affected
• Patients who can be treated with conservative treatment alone, unless there is evidence of at least 6 months failed previous treatment
• Systemic disease including AIDS, HIV, Hepatitis or any other disease that would prevent normal organ and marrow function.
• Patients undergoing systemic cortisone treatment or immunosuppressive therapy (e.g. avascular necrosis)
• Patients undergoing active cancer therapy (chemotherapy, radiation treatment).
• History of alcohol abuse or illegal drug use.
• Participation in any other device or drug trial within 3 months prior to the inclusion in the study
• Presence of at least one contraindication for DBX® Putty