Comparative Retrospective Study of PLLA and PLLA/HA Pins for Osteochondral Fragment Fixation in Osteochondral Lesion of the Talus.

Abstract

Background: Postoperative osteolysis may be observed around poly-l-lactic acid (PLLA) pins in osteochondral fragments fixation for an osteochondral lesion of the talus (OLT). Hydroxyapatite (HA) improves biocompatibility, osteoconductivity, and mechanical strength when added to PLLA. This study aimed to compare the characteristics of osteolysis and clinical outcomes of fixation for OLT with PLLA pins vs PLLA/HA pins.

Methods: Thirty-one ankles undergoing fixation with bioabsorbable pins for OLT were included. Fourteen ankles were fixed with PLLA/HA pins and 17 ankles with PLLA pins. Magnetic resonance imaging (MRI) was taken pre- and postoperatively at 1 year. Osteolysis around pins, bone marrow edema (BME) in the talus, and pin insertion angle on MRI, the American Orthopaedic Foot & Ankle Society (AOFAS) score, and the visual analog scale (VAS) pain score were compared between the 2 groups pre- and postoperatively at 1 year. AOFAS score at the final follow-up was also compared between the 2 groups.

Results: The osteolysis area was significantly smaller in the PLLA/HA group in both coronal and sagittal planes on MRIs obtained 1 year postoperatively. There were no significant differences in osteolysis frequency, BME area, AOFAS score, and VAS pain score. Lower pin insertion angles measured on either sagittal or coronal planes were generally associated with greater amounts of osteolysis.

Conclusion: We did not find superiority using PLLA/HA pins compared with PLLA pins to fixate talar osteochondral fragments. However, PLLA/HA pin use was associated with less osteolysis around pins compared with PLLA pins.