Osteochondral Defects (OCD) or Articular Cartilage Defects
Biology: Why does it occur?
In general OCDs have three different mechanisms that affect three different age groups.
- 10 year to 28 year age group – Osteochondritis Dissecans (the acronym is OCD also). Its mechanism is poorly understood, but results in a discreet cartilage defect usually in the knee. These may or may not be associated with trauma.
- 18year to 50+years – usually traumatic secondary to sports injuries. Usually associated with other injuries such as meniscal tears and ACL tears (knee), or ligament sprains in the ankle.
- 60+years – Spontaneous Osteonecrosis (SPONCRE) or Avascular Necrosis (AVN) leading to an OCD. This occurs due to a sudden loss of blood supply to a discreet area of the knee or hip due to unclear reasons. It results in loss of cartilage, and frequently leads to diffuse osteoarthritis of the affected joint quite rapidly.
Common Diagnostic Techniques
Physical Exam: A thorough physical examination is then conducted by your surgeon. X-Rays: Plain radiographs (X-Rays) are the most important diagnostic study that is performed initially. For the knee and ankle specialized views will be obtained by your surgeon. Usually these are weight bearing x-rays – i.e.: you will be standing for the x-rays.
X-Rays: Plain radiographs (X-Rays) are the most important diagnostic study that is performed initially. Several views will be obtained to diagnose the condition.
Bone Scan: In certain situations a bone scan maybe useful in making the diagnosis.
Treatment depends on which of the three variants you have.
Osteochondritis Dissecans – usually treated operatively as soon as diagnosis is made to make use of the healing response in the early phases of the injury. The surgery is usually performed arthroscopically, and is aimed at reinserting the loose OCD fragment to where it broke off from with bio-absorbable pins. Sometimes, the loose fragment grows in size and no longer fits the defect. In this situation it is removed, and an alternate method of resurfacing the defect is utilized. Please see the FAQ section for explanation of procedures.
Traumatic OCD – usually treated operatively as soon as diagnosis is made. The surgery is usually arthroscopic, and the choices are Microfracture, Mosaicplasty, or Autologous Chondrocyte Implantation (ACI) depending on the size and depth of the lesion. An Osteotomy might be necessary to realign the knee in certain patients.
Spontaneous Osteonecrosis – usually treated non-operatively with crutches to unload the knee for 6 weeks, medication to help with the pain and help regenerate bone (Calcitonin), and physical therapy for joint range of motion and edema control. If non-operative treatment fails, operative intervention is undertaken. Arthroscopy is usually not very successful unless there is other pathology within the knee such as a meniscus tear. Arthroscopy can make the symptoms worse, and lead to a more rapid degeneration of the articular cartilage. Microfracture maybe attempted in this situation, but the results are variable. Mosaicplasty and ACI are not indicated. The definitive operative procedure is a uni knee replacement (UKA) or a total knee replacement (TKA) for the knee, and total hip replacement (THA) for the hip.