A Delayed Formation of Pretibial Pseudocyst After Anterior Cruciate Reconstruction from Bioabsorbable Interference Screws: A Report of Two Cases and Short Review of the Literature.

We report two cases of subcutaneous pretibial pseudocyst formation after 7 and 10 years of successful anterior cruciate ligament reconstruction with poly-L-Lactide acid bioabsorbable interference screw fixation with autologous hamstring graft. Both patients underwent surgical excision of the lesion and curettage of the tibial tunnel aperture. The screw had undergone complete resorption at the time the cyst occurred. There was no communication between the tunnel aperture and the knee joint. Both patients had an uneventful recovery returning to their preinjury activity level. Histologic analysis revealed foreign body reaction to the crystalline fractions of the bioabsorbable material with aggregated histiocytes. To our knowledge, this is the first case report describing a delayed formation of pretibial pseudocyst after anterior cruciate reconstruction with bioabsorbable interference screw.