Is Cartilage Grafting Better Than Drilling For Osteochondral Lesions?
Yes, Tom Chang, DPM cites recent advances in the use of autografts and allografts, and emphasizes that hyaline cartilage is more durable than fibrocartilage.
The last few years have seen the introduction of evolving techniques for osteochondral defects for talar lesions. These techniques include the use of autografts and allografts in single plugs or mosaic patterns.
Surgeons have utilized similar techniques for chondral defects in the metatarsal heads as well. The degenerative changes in patients with hallux valgus or hallux limitus can present with lesions that can fall into the traditional types I to IV. Patients can also occasionally present with cystic changes within the talar dome or metatarsal heads. Magnetic resonance imaging (MRI) may be useful to image these cystic changes and recognize the deep marrow edema within the involved bone.
Most of our traditional techniques include subchondral drilling, abrasion arthroplasty or microfracture. Penetration of drill holes through the subchondral bone plate will stimulate mesenchymal cells within the bone marrow to form fibrocartilage. This form of repair is functional but fibrocartilage definitely does not have the durability and strength of normal hyaline cartilage. A good analogy is to compare normal skin to a healed scar. The scar tissue is functional but never is as supple and healthy as normal skin.
Studies have shown short-term success with fibrocartilage repair but patients with such joints usually return with pain and degenerative damage to the same areas within two to four years, especially when the repair is in weightbearing joints of the body. Once the repair fibrocartilage fails, the joints continue to undergo degeneration rapidly and progress onto end-stage arthrosis within a short amount of time.
A Closer Look At Allografts And Autografts
In recent years, surgeons have used other forms of cartilage repair that attempt to replace these osteochondral defects with hyaline cartilage options. These have been in the form of both allografts and autografts. Several authors have described autografts as having good medium to long-term results. Hangody, et al., reported a seven-year follow-up on osteochondral autografts from the knee to the ankle joint. Osteochondral autografts have shown promise in providing the hyaline repair many have been seeking for these difficult lesions.1
The available sites of donor tissue have initially been from the knee, mainly in the notch region or the lateral femoral condyle. Donor cartilage can only come from “non-essential, non-weightbearing” areas of a joint space. Although there is adequate surface area there, the biomechanical characteristics of this knee plug are not ideal for the loading properties of the ankle and the foot. The cartilage is also thicker than in the ankle and joints of the foot. Therefore, it would be helpful to have donor sites from the same joint in question.
Key Considerations With The Harvesting And Application Of Grafts
We are now taking osteochondral grafts from the medial and lateral talar surfaces as well as the spring ligament area. There have been reports in the literature of successful outcomes with osteochondral autografts from the medial and lateral talar surfaces.2
The spring ligament site, which derives from the plantar medial navicular, has become popular due to the radius of curvature one sees on many diseased joint surfaces. It is helpful to try and match this when possible. In the majority of cases, the donor sites are not backfilled and we have not seen any hemarthrosis to speak of.
In communication with multiple members of the Podiatry Institute, surgeons have performed over 50 spring ligament grafts without talonavicular joint pain.
Surgeons have utilized frozen allografts in the past but their popularity has dwindled as fresh grafts have become more common. Fresh talar allografts have also gained popularity recently with success and one can perform them for both unipolar (single sided) and bipolar (double-sided) repair. Brage and Bugbee have reported good success with a variety of these repairs in the ankle.3