Activation of the complement system and adverse effects of biodegradable pins of poly-lactic acid (Biofix®) in osteochondritis dissecans

Abstract

Biodegradable pins of polyglycolic acid (PGA) or c polylactic acid (PLA) have been used in the treat- d ment of fractures and osteotomies during the past 5 s years. Adverse effects reported have included c swelling at the implantation site and sinus formation, considered to represent nonspecific foreign- l< body reactions. Recent reports, however, have ti shown severe reactions after intraarticular fracture ti fixation. Reactions in 2 patients, treated with poly- n lactic pins for osteochondritis dissecans (OCD) in our hospital, prompted the present clinical investi- s gation and further evaluation of the complement- p activating potential of polylactic pins. 10 knees underwent arthroscopic fixation of an OCD-lesion with Biofix@ (PLA) pins. Clinical follow ups were carried out at 2, 6, and 12 weeks and at 6 and 12 months. Blood samples were collected from 5 patients 9-24 months postoperatively for biocompatibility tests. Quantification of human C5a des Arg was performed with a recently developed sandwich ELISA technique, using neoepitope-specific monoclonal antibodies. 6 knees developed diffuse swelling and a pro- longed postoperative course. 2 patients had a par- ticularly prolonged course which could not be at- tributed to infection. Levels of C5a des Arg in plas- ma incubated in the presence of polylactic acid were higher than in plasma incubated in the ab- sence of PIA. The high frequency of long-term postoperative inflammatory signs in these knees treated for OCD and the demonstration of a complement activation potential of PLA pins warrant further studies on the biocompatibility of this material. Until more information is available, we do not recommend intraarticular use of PLA pins.