Osteochondritis Dissecans (OCD) lesions sometimes do not heal despite initial treatment, surgical or non-surgical, to save the OCD fragment. This can result in a hole or defect on the surface of the joint where the cartilage and bone are either missing or damaged beyond repair. If the size of the lesion is large enough and is left untreated, it can lead to further joint deterioration. This may result in an increase in size of the lesion as well as damage to surrounding bone and cartilage, leading to further joint degeneration (arthritis). In order to prevent the progressive changes, the lesion area will typically need to undergo a surgical procedure to restore the joint surface.

Treatment options for bone and cartilage lesions from OCD include both nonsurgical and surgical methods. Non-surgical techniques may include restriction of activities and/or non-weight bearing on the affected limb; joint injections with stem cells or lubricating agents (viscosupplementation); or use of oral supplements including chondroitin sulfate. These non-surgical measures have limited effectiveness in larger lesions, which is typical of OCD lesions. The goal of surgical intervention is to restore the joint surface in order to eliminate pain and recover function, allowing a return to activity and sports. Ideally this improvement should last many years and hold up to the demands of all activity. Your physician will discuss with you the options for treatment and recommend a treatment plan based on your specific situation.

Surgical Options
1. Structural biologic tissue replacements
Structural biologic tissue replacements consist of harvesting bone and cartilage (osteochondral grafts) to fill the defect. The two main options are grafting tissue from the same individual (autograft) of from a different individual (allograft).

Osteochondral autograft transfer (OAT) is used to fill small to medium sized defects (Figure 1) and osteochondral allografts (OCA) are used to fill large defects (Figure 2). Autografts come from some other location in the joint of the patient being treated. Autografts provide the benefit of more predictable healing and lower cost, but are limited in the size of lesion that can be treated. Allografts are harvested from a recently deceased individual (organ donor) and must be transplanted within a few weeks from the harvest date. Allografts provide more tissue for transfer and are therefore used to treat larger lesions; allografts are associated with a higher cost. Both OAT and OCA provide normal structural architecture of the bone and cartilage in contrast with nonstructural biologic tissues, which do not have the same histologic appearance of the cartilage.

Figure 1: Two views of osteochondral autograft transfer. There are two plugs used, one is 10mm in diameter and one is 4mm in diameter.

Figure 2: Osteochondritis Dissecans lesion (A) and same lesion with Osteochondral Allograft in place (B).

2. Nonstructural biologic tissues

Nonstructural biologic tissues include microfracture and cell based treatment options.

Microfracture involves the drilling or picking of small holes in the base of the lesion in order to access the intramedullary canal within the bone. This stimulates the intramedullary contents to fill the defect with fibrocartilage. Fibrocartilage is “scar” cartilage and is different than normal articular cartilage. It is not as durable as articular cartilage, so this technique is used sparingly.

More common are cell based treatment options which include matrix-associated autologous chondrocyte implantation (MACI) (Figure 3) or particulated juvenile allograft cartilage (PJAC) (Figure 4). In the MACI technique, cartilage tissue from the patient’s involved joint is harvested, typically arthroscopically, and sent to a lab. The harvested cartilage cells are then used to create a “sheet” of cartilage cells that can be implanted into the patient’s defect during a second procedure. The benefits of this procedure include a proven track record of success, ability to be used on lesions of almost any size and shape, and it is not limited by donor availability. Drawbacks include the need for multiple surgical procedures and the associated higher cost. In the PJAC technique, juvenile donor cartilage is prepared and stored by non-profit tissue donation facilities. The cartilage is prepared in small cubes which are secured into the OCD defect in one surgery. The benefits of this procedure are that it requires only one surgery and can be used on lesions of any size and shape. The drawbacks are that it is susceptible to donor availability and has a high cost. For both MACI and PJAC, the utility of these techniques for an OCD lesion involving a bone defect is not as well understood as when there is only a cartilage lesion rather than a bone and cartilage lesion together, which is present in OCD.

Figure 3: Osteochondral defect after preparation (A) and after particulated juvenile allograft cartilage (PJAC) implantation (B).

Figure 4: Osteochondral defect following matrix-associated autologous chondrocyte implantation (MACI) implantation.