A Stepwise Approach For Osteochondral Lesions Of The Talus
A Closer Look At Juvenile Allograft Cartilage Implantation
The DeNovo graft (Zimmer) is a newer product that uses scaffold-free allogeneic juvenile cartilage, which one can implant into a defect and secure with a fibrin sealant.1 This technique is an efficient, one-stage procedure that addresses focal defects. The use of juvenile cartilage amplifies the amount of immature chondrocytes, which are more metabolically active and capable of spontaneous repair.10 The enhanced activity of young chondrocytes permits differentiation into hyaline-like cartilage instead of fibrocartilage.9
The DeNovo graft is effective in treating lesions up to 2.5 cm2 but no larger than 5 cm2. Perform arthroscopic debridement on the joint and clearly define the lesion before suspending the graft in fibrin glue. Then place the graft into the lesion, making sure the graft fits flush. Enforce strict non-weightbearing for six weeks in a below-the-knee fiberglass cast, allowing the graft to incorporate into bone. Follow this with protected weightbearing in a removable cast boot for approximately two weeks. After removal of the fiberglass cast, physical therapy starts with range of motion exercises.
What You Should Know About The Osteochondral Autograft Transfer System
We reserve the Osteochondral Autograft Transfer System (OATS) procedure (Arthrex) for lesions of moderate to large size (1.5 cm2 to 3.0 cm2) with frayed cartilage, necrotic bone and underlying fibrous tissue. This is a one-step procedure requiring harvesting the graft from a donor site and then placing the graft into the talar osteochondral lesion via an open arthrotomy.
Enforce strict non-weightbearing for six weeks in a below the knee fiberglass cast, allowing the graft to incorporate into bone. Then patients begin protected weightbearing in a removable cast boot for approximately two weeks. Once the fiberglass cast comes off, physical therapy starts with range of motion exercises.
Disadvantages with the OATS procedure include the limited accessibility of donor sites, which would facilitate the treatment of larger lesions. There is also a technical challenge of symmetry as round autologous osteochondral plugs fill irregularly shaped defects.11 Subsequently, the dead space between the circular graft and the unfilled lesion heals as fibrocartilage.
Clinicians should consider the patient’s age, activity level, health and pain level when selecting the proper treatment regimen for osteochondral lesions of the talus. The location, size and stage of the lesion are also important factors to consider when choosing the appropriate surgery. Arthroscopic microfracture has proven successful in lesions smaller than 1.5 cm2 in patients 50 years old or younger but the technique is not capable of restoring the hyaline cartilage. Supplementing arthroscopic microfracture surgery with bone marrow aspirate has shown encouraging results in our experience. This method is less invasive with an early return to activity for the patient.
New modalities such as the DeNovo graft have increased the number of treatments for osteochondral defects. The technique for the graft is relatively simple to perform, has low patient morbidity and stimulates hyaline cartilage. Also, one can use the graft to treat larger lesions up to 2.5 cm2 and it does reinstate the hyaline cartilage. Patients less than 50 years old with lesions larger than 2.5 cm2 or with prior failed surgery would most benefit from the OATS procedure. The OATS procedure is a more invasive technique and requires a donor site.
Currently, there are many procedures for the treatment of osteochondral lesions of the talus. Each surgical modality has its indications as well as pros and cons. In our practice, we evaluate the advantages and disadvantages of each procedure, determining which is best for each individual case.