Osteochondritis dissecans is a common problem in young people and the exact cause is not known. This disease is characterised by a weakened bony surface and any minor trauma results in breaking off of the bony fragments. The damage involved is from a small part to a large area of bony surface. The disease usually occurs in the inner part of the thigh forming the knee joint. The person may not have any pain during the early phase and one can easily ignore treatment. If the bony pieces become detached and fall into the joint space, it may cause locking of the knee. If left untreated, it leads to early osteoarthritis (wear and tear).

There was not much specific treatment earlier. But with advances in arthroscopy, new techniques have evolved. By arthroscopy one can confirm the diagnosis and get to know the severity and extent of articular cartilage damage. The treatments associated with this condition may vary from simple to complex procedures. These may include shaving, abrasion chondroplasty, micro-fracture, osteotomy, periosteal autografts and perichondral autografts. These produce suboptimal results and often fail to regenerate the original hyaline cartilage.

However, there have been recent advances in treatment most of which can be done through an arthroscope. All these techniques are reproducible with good prognosis. The ability to resurface the damaged areas with original hyaline cartilage is high. These techniques are chondrocyte implantation and osteoarticular autograft transfer procedures.

The goal is to develop a new articular cartilage surface as before; to eliminate pain; prevent wear and tear and regain the original gliding surface of the smooth articular cartilage (function).

Before the advent of arthroscopy, CT and MRI investigations, diagnosis was difficult and was often left untreated. But now the scenario has changed. With advances in arthroscopic treatment and investigation modalities like CT and MRI, the condition can be diagnosed early.

Chondrocyte implantation

In this technique, articular cartilage biopsy from a good site is obtained arthroscopically from the knee. This good articular cartilage tissue is sent for tissue culture to propagate millions of viable cartilage cells (chondrocytes). Through meticulous procedures, the viable cells are implanted in the defective area. These cells stimulate the formation of new cartilage layer resembling the original.

The drawback in this technique is that :

Osteoarticular autografting

The defective area of the joint is replaced by good bone with healthy articular cartilage borrowed from a non-weight bearing area of the same joint. It is an effective, reproducible and cost-effective means of restoring articular cartilage.

In this technique, small cylindrical good bones are taken from non-weight bearing area of the same thigh bone. These bones are then transplanted to the defective area where recipient holes are made. By this technique, transplanted bone fills up almost 80 per cent of the lost surface area. This technique ensures regeneration of original quality articular cartilage as well as normal contour of the joint.

Advantages:

Patients with focal chondral defects in a joint due to OCD or injury need not restrict their activity or fear early wear and tear. Newer forms of treatment like autografting can save joints and they can get back to a normal routine.

BLESSON THOMAS
Dr. P. SRIPATHY RAO
Dr. DAVID V. RAJAN

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