A case of ankle osteoarthritis associated with lateral premalleolar bursitis caused by chronic ankle instability.

Introduction: Lateral premalleolar bursitis develops on the dorsolateral aspect of the foot anterior to the lateral malleolus, distinct from lateral malleolar bursitis located just around the lateral malleolus.

Presentation Of Case: A 71-year-old woman visited an orthopedic clinic about 40 years after an episode of ankle sprain and was diagnosed with lateral premalleolar bursitis and osteoarthritis of the left ankle. Stress radiography revealed left ankle anterolateral malleolar bursitis with varus and anterior instability. We opted for less invasive arthroscopic ankle arthrodesis over open resection to stop the communication of the bursitis with the ankle joint. The lateral premalleolar bursitis was located just over the anterolateral portal. The remaining cartilage in the talotibial joint was removed and the subchondral surface was exposed and curetted down to a bleeding surface by ankle arthroscopy. The talotibial joint was fixed with 3 6.0-mm cannulated cancellous screws. The foot and ankle were immobilized by cast for 4 weeks. Bony union was achieved about 8 weeks postoperatively. The patient could perform daily activities without pain and with no recurrence of the lateral premalleolar bursitis at the 1.5-year follow-up.

Discussion: To our knowledge, this is the first report on arthroscopic arthrodesis for ankle osteoarthritis with recalcitrant lateral premalleolar bursitis caused by the check valve mechanism of chronic ankle instability after old ankle sprain.

Conclusion: We report a case of arthroscopic arthrodesis for osteoarthritis of the ankle associated with lateral premalleolar bursitis caused by the check valve mechanism of chronic ankle instability after old ankle sprain.