Emerging Advances In Ankle Cartilage Repair
Damage to the cartilage in any joint of the body can have detrimental effects on the function and performance of that joint. This is particularly true for the cartilage of the ankle joint, specifically at the talar dome. Due to the body’s inability to repair cartilage to its original form, treating patients with osteochondral lesions has proven to be a challenge to even the most competent foot and ankle practitioner.
In many instances, conservative treatment with immobilization and non-weightbearing is adequate enough treatment to relieve symptoms. This is especially the case for stage I and II lesions.1 However, if conservative treatments fail for these lesions or if the lesion is significantly larger and more consistent as is the case with stage III or IV lesions, one must consider more aggressive options.
Arthroscopy with debridement and microfracture has generally been the predominant first-line surgical treatment for talar dome lesions. However, recurrence of symptoms following microfracture is not uncommon, especially with larger, deeper lesions, or those exhibiting subchondral damage.
Fortunately, there has been a lot of progress in the field of cartilage repair in recent years and this has led to improvements in the treatment of osteochondral lesions of the talus. The collective goal of all of these methods is to promote more hyaline-like cartilage as opposed to the fibrocartilage that is present following microfracture treatment.2 Accordingly, let us take a closer look at these emerging options.
What You Should Know About Autologous Cartilage Implantation
If treatment with microfracture has previously failed, autologous cartilage implantation may be a viable next step. Surgeons may also consider primary autologous cartilage implantation if the diameter of the lesion is greater than 2 cm or if extensive subchondral cysts are present like one might see with stage IV defects.3
Autologous cartilage implantation is a two-step procedure involving the harvesting of cartilage from a non-weightbearing surface of a joint, such as the supralateral femoral ridge of the knee.2 Other options include the non-weightbearing anterior surface of the talus.3 One would subsequently send the graft to the lab where chondrocyte isolation and proliferation takes about four to six weeks.
Surgeons would then perform a second procedure for transplantation. Generally, an open procedure is necessary for adequate exposure. This may or may not include a malleolar osteotomy depending on the size and location of the lesion. One would then implant the chondrocyte graft onto the defect after proper debridement. A periosteal flap is required in order to secure the graft and this may prove to be a tedious suturing process. However, a newer version of the procedure known as matrix-based chondrocyte implantation obviates this by fixing the chondrocytes in a collagen matrix. One can secure the graft with fibrin glue and no periosteal flap is required.
Regardless of this improvement, autologous cartilage implantation has fallen out of favor in the past few years due to the need for a staged, open procedure. Autologous cartilage implantation has predominantly been replaced by use of the DeNovo® NT Natural Tissue Graft (Zimmer), which we will discuss later in this article.
A Closer Look At The Osteochondral Autologous Transplantation/ Mosaicplasty
Indications for performing an osteochondral autologous transplantation surgery (OATS) or mosaicplasty procedure include a lesion that not only has a large cartilaginous component but a significant osseous component as well.4 This option can also be a last resort for lesions that have been recalcitrant to previous surgical treatment.