A Stepwise Approach For Osteochondral Lesions Of The Talus
Osteochondral defects of the talus embody a broad category of injuries from fibrillation of the articular cartilage to full depth loss of cartilage and bone.1 These defects are fairly common injuries that are most often linked with an ankle sprain or fracture.
In the literature, the incidence of osteochondral lesions ranges from 0.09 percent of all talar fractures to 6.5 percent of all ankle sprains.2,3 However, Ferkel and colleagues found a group of patients with unexplained chronic ankle pain had an incidence of misdiagnosis or delayed diagnosis of osteochondral lesions as high as 81 percent.4
Chronic pain, swelling, subchondral cyst formation, functional impairment and end-stage osteoarthritis may result from a failure to treat an osteochondral defect properly.5 Bracing, physical therapy and immobilization are a few of the non-operative treatment modalities for osteochondral defects although most are refractory to conservative therapy. Berndt and Harty found that 75 percent of conservatively managed lesions had poor outcomes.6
O’Driscoll summarized the options for operative treatment of an osteochondral defect by stating that one can restore, replace, relieve or resect articular cartilage.7 Surgical treatments for osteochondral defects include an array of options ranging from a minimally invasive arthroscopic microfacture procedure to extensive ankle arthrotomy with malleolar osteotomies and fresh osteochondral allografts. At the University Foot and Ankle Institute, we have been following a stepwise approach in the treatment of osteochondral lesions that we will describe below.
Combining Arthroscopic Microfracture Surgery With Bone Marrow Aspirate
For lesions less than 1.0 cm2, we have found that arthroscopic microfracture surgery of the lesion in conjunction with bone marrow aspirate stem cell injection therapy provides good results with quicker recovery time. Also, the relative ease of performing this procedure arthroscopically makes it an excellent first-line treatment choice.
Microfracture relies on the stimulation of marrow chondroprogenitor cells within the underlying marrow, which populate the fibrin clot in the talus defect and yield a fibrocartilaginous matrix.8 This unorganized matrix is composed of fibrocytes, chondrocytes and chondroblasts that protect the surface from excessive loading.
We have found better results and greater patient satisfaction by augmenting bone marrow aspirate injection of stem cells with microfracture surgery. One performs the bone marrow aspiration at the time of surgery, taking the bone marrow from the ipsilateral calcaneus prior to exsanguination and inflation of tourniquet. The marrow then spins down and one injects the mesenchymal stem cells of the marrow directly into the ankle joint.
In cartilaginous defects larger than 1.0 cm2 and/or lesions with large subchondral cysts, we do not perform reparative techniques such as microfracture. The reparative process of microfacturing lays down newly formed fibrocartilage comprised of both type I and II collagen, which is weaker than the native hyaline cartilage and therefore not sufficient for larger defects.7,9