Aims: Bioabsorbable self-reinforced polylevolactide (SR-PLLA) fixation devices have been used for several indications within orthopaedics and traumatology since the eighties, but their long-term effects in clinical use and in patients with rheumatoid arthritis (RA), however, are not wellknown, and were evaluated at the present study. Methods: Arthrodeses were fixed with SR-PLLA devices in 27 patients with RA (32 procedures: 22 of the wrist with rods, 7 of the talocal-caneal-calcaneocuboid-talonavicular (triple) and 3 of the talocrural (ankle) with screws and rods) and 16 ankle fractures with screws and/or rods. Outcomes were assessed clinically and radiographically in the long-term (mean 6.0, range 1.1–11.7 years). Computed tomography (CT) evaluation of the implants in a subgroup of 33 patients was performed. Results: All but one wrist fusion, 5/7 of triple fusions, 1 of 3 ankle fusions and all ankle fractures united. Functional results were generally good. In 5 ankle fractures degrading polymer material originating from uncut screw heads led to tissue reactions, and in 2 cases to exceptionally slow degradation. Conclusions: SR-PLLA implants served well as fixation devices for wristand triple arthrodeses in patients with RA and for ankle fractures. Difficulties occurred in bony healing of ankle arthrodeses. The SR-PLLA implants showed high biocompatibility as long as the correct operative technique was followed. Inside the bone, SR-PLLA implants degraded in 4 to 6 years. Slight bone resorption occurred.

Aims: This presentation deals with our clinical experience based on experimental studies when using bioabsorbable fixation devices in bone, joint and ligament surgery. These devices were clinically introduced by us in the treatment of fractures in the extremities in the mid – 1980’s. Our own list of publications consists of 1137 publications since 1978 including, 26 academic dissertations. Before and during our clinical studies over 6500 animals were operated on in our experimental studies. Macroscopic, radiographic, microradiographic, histologic, histomorphometric and fluorochrome studies were done. Methods: The strength, strength retention, degradation, bone changes, healing of fractures, and injuries, and the fixation properties of the implants were investigated in vivo. Results: In Kuopio (814) and in Helsinki (3555) 4369 operations were done using bioabsorbable self-reinforced (SR) fixation implants mainly polyglycolide or poly-L-lactide during 1984–2001. In Helsinki there were 2766 trauma operations and 789 orthopaedic operations. The postoperative clinical course was uneventful in 82% of the patients. The complications included wound infection in 4.0%, failure of fixation in 3.9%, a non-infectious foreign-body reaction (sinus) in 1.9% (with SR-polyglycolide implants) but not with SR-polylactide implants. Conclusions: Due to the biodegradibility of the devices, implant removal procedures were avoided.

Cytological analysis of material aspirated from the effusion which occasionally develops around a polyglycolic acid (PGA) osteosynthesis implant showed a predominance of inflammatory monocytes and in particular lymphocytes. In order to discover whether PGA implants are immunologically inert, density gradient-isolated peripheral blood mononuclear cells were cultured in 0.2 ml of 10% delta FCS-RPMI 1640 culture medium supplemented with 10 mg PGA. Phytohaemagglutinin (PHA) lectin, a purified protein derivate of tuberculin (PPD) antigen and culture medium alone were used as positive and negative controls. We studied lymphocyte activation kinetics on days 0, 1, 3 and 5. Major histocompatibility complex locus II antigen (MHC locus II antigen) and interleukin-2 receptor (IL-2R) expression were analysed using the avidin-biotin-peroxidase complex (ABC) method and lymphocyte DNA synthesis by using 3H-thymidine incorporation and beta-scintillation counting. Especially on culture days 0 and 1, lymphocytes and monocytes were seen by light microscopy to be attached to PGA particles. However, our results show no PGA-induced lymphocyte DNA synthesis, but PGA-induced MHC locus II antigen and IL-2R activation marker expression was seen, greater than in negative controls, but less than that seen in PPD antigen driven lymphocyte response. This suggests that PGA is an immunologically inert implant material, but it does seem to induce inflammatory mononuclear cell migration and adhesion, leading to a slight non-specific lymphocyte activation. This activation is lower than that seen in mitogen and antigen-driven lymphocyte responses.