Osteochondral Lesions of Talus (OLT) - (cartilage defect in ankle)

• Pain in ankle on long standing – initially pain is intermittent as the disease progresses pain becomes constant with increased severity and not relieved by medications or rest
• Repeated swelling around ankle on exertion/sports
• Associated with recurrent ankle sprains then there will be feeling of giving away – difficulty walking on uneven surface and pain and swelling after such episodes
• When the fragment is completely detached from the parent bone then there can be locking episodes or catchy sensations on ankle movements.
  

Figure 1: A: MRI coronal and sagittal images(RED ARROW), B: OLT with displaced cartilage, C: Post debridement, D: Microfracture using microfracture pick, E: Completed procedure

Figure 2 : A&B: Plain radiographs showing OLT, C: Aspiration of bone marrow from iliac crest, D: Medial malleolar osteotomy and demonstrating the lesion(Blue Arrow), E: Bone marrow aspirate concentrate over the defect, E: Completed medial malleolar fixation using 4mm cancellous screws, E: Post-operative radiograph

In very early stages activity modification can be beneficial – can delay the progression of the disease. Activity modification means activities/sports that lead to symptoms should be avoided or shift to safer alternatives.

Depending on the size and accessibility of the lesion various surgical options are available

•  Bone marrow stimulation : minimally invasive technique where the defect is identified and after preparation, with special instruments holes are created. This will stimulate special cells from the bone marrow to shift towards the defect and lead to formation of the new cartilage(Figure 1).
• Osteochondral autograft transfer : This is a technique where cartilage from the non-weight bearing part of the knee will be taken and transferred to the damaged area.
• Autologous chondrocyte implantation : This is a technique where cartilage biopsies  from the knee joint is taken and sent to the laboratory for tissue engineering can culture where cartilage forming cells will be nurtured which will then be transferred in the defect. It is a staged procedure and has proven benefits.
• BMAC: Bone marrow aspirate Concentration is a single stage procedure, where the bone marrow is aspirated from the iliac crest and concentrated by centrifugation. Then the concentrate is mixed with the thrombin and layed over the defect. The principle of this surgery is that the stem cells are activated to form hyaline cartilage over the cartilage defect(Figure 2).