PLGA Conical Nail Fixation for Acetabular Chondrolabral Delamination in Femoroacetabular Impingement Promotes Cartilage and Labrum Regeneration in a Porcine Model

Background: Acetabular chondrolabral delamination (ACD) is one of the most common hip cartilage injuries. However, there are very limited clinical treatments for this injury. Purpose: To evaluate the effectiveness of poly (lactic-co-glycolic acid) (PLGA) conical nail fixation in the treatment of acute and chronic ACD in a porcine model. Study Design: Controlled laboratory study. Methods: In this study, 24 pigs underwent surgically induced delamination of the chondrolabral junction. Pigs were randomly divided into 3 groups: the control group (delaminated chondrolabral junction without treatment), ACD acute refixation (ACDA) group (delaminated chondrolabral junction fixed with a PLGA nail), and ACD chronic refixation (ACDC) group (placement of a nonabsorbable spacer at the stripped chondrolabral junction for 6 weeks before fixation with a PLGA nail). Porcine specimens underwent magnetic resonance imaging (MRI), hematoxylin and eosin staining, safranin O/fast green (SO/FG) staining, immunohistochemistry examination (collagen 1, collagen 2, and collagen 10), and immunofluorescence examination (SOX9 and aggrecan) to evaluate the chondrolabral regeneration at 6 and 12 weeks postoperatively. Results: MRI showed focal discontinuity of cartilage and fluid located between the acetabular cartilage and subchondral bone plate in the control group. The acetabular cartilage stained with SO/FG showed significantly more proteoglycan deposition at 12 weeks in the ACDA group than in the control group (P = .0109) and ACDC group (P = .0484). In accordance with the results of the SO/FG and collagen 10 staining, the aggrecan of the femoral head at 6 and 12 weeks was upregulated in the ACDA group (P < .0001) and downregulated in the ACDC group (P < .0001). Conclusion: PLGA conical nail fixation achieved a good treatment outcome on MRI and histological evaluations. Early treatment upregulated the expression levels of SOX9 and aggrecan and promoted proteoglycan deposition. Clinical Relevance: The PLGA conical nail fixation technique may be a viable and effective treatment approach for patients with ACD in clinical practice.