Osteochondral transplantation for the treatment of osteochondral defects at the talus with the Diamond twin system^® and graft harvesting from the posterior femoral condyles

The aim of this study is to analyze clinical results after osteochondral cylinder transplantation for osteochondral defects at the medial or lateral talar dome using the Diamond twin system (Karl Storz). We hypothesize that grafts harvesting from the posterior femoral condyles are associated with less donor site morbidity than reported by previous studies.

We have surgically treated 20 patients with an osteochondral defect of the talus by osteochondral transplantation with the Diamond twin system via an osteotomy of the ankle. The osteochondral cylinders were harvested from the posterior aspects of the femoral condyles of the ipsilateral knee. The defects at donor site were filled with a bone substitute of tricalcium phosphate (Synthricer, Karl Storz). The mean age was 25.4 years. After a mean time of 12.6 months, the screws at the medial malleolus were removed and an arthroscopy was performed. The functional outcome was evaluated with the visual analog scale for pain at walking, running, stair climbing, quality of life at the time of implant removal and at a mean follow-up of 25.8 months. Activity was assessed with the Tegner scale. Knee function was evaluated with the Lysholm score.

In one case, the osteochondral cylinder did not heal and an osteochondral fragment was removed arthroscopically. In all other cases, the osteochondral cylinder was stable with surrounding cartilage. The average ICRS Cartilage Repair Assessment was 10.1 points (±1.3). All malleolar osteotomies healed radiologically. In 15 patients, a synovectomy and local debridement of the ankle were performed at second-look arthroscopy. Ankle pain at walking, running and stair climbing as measured by a visual analog scale (10-0) decreased significantly from preoperatively to the first follow-up (mean 12.6 months) and to the second follow-up (mean 25.8 months). The ankle-related quality of life increased significantly from preoperatively to postoperatively. There was no significant change in the Lysholm score. The activity measured with the Tegner activity scale increased significantly from preoperatively to the last follow-up, but only two out of nine patients continued pivoting sports.

Autologous osteochondral grafting with the Diamond twin system is a reliable treatment option for symptomatic osteochondral defects of the talus. After 1 year, the majority of patients had still some complaints. However, after screw removal and second-look arthroscopy, the pain and ankle-related quality of life further improved.

The donor site morbidity after graft harvesting from the posterior aspects of the femoral condyles is lower than previously reported.