[Cartilage damage caused by a dislocated resorbable interference screw of poly(L-lactide) 46 months after anterior...

The case of a 44-year-old male patient is reported, who was operated 4 years after a cruciate ligament replacement. A nearly completely intact biodegradable screw was removed arthroscopically. The screw dislocated from the tibial canal into the joint and caused damage to the retropatellar cartilage which was treated by debridement and lateral release. A material analysis was done on the explanted screw which showed no material fault. A review of the literature reporting adverse events connected to biodegradable implants was carried out. Nine papers reporting about adverse event are cited. There seem to be three main problems: delayed degradation, foreign body reaction and the filling of graft tunnels with non-ossified tissue. Instructions for the use of biodegradable interference screws were requested from seven manufacturers to compare the given information about the degradation behaviour. The information given on the period of time until the screws would be completely resorbed were heterogeneous, ranging from no specific information about the time span at all up to 24 months. More research is needed to identify the degradation behaviour more precisely and clarify the potential risks connected to biodegradable implants. Their use should be reconsidered critically.