Labral reconstruction with polyurethane implant

Surgical treatment of labral injuries has shifted from debridement to preservation over the past decades. Primary repair and secondary augmentation or reconstruction techniques are aimed at restoring the labral seal and preserving or improving contact mechanics. Currently, the standard of care for non-repairable tears favours the use of auto- or allografts. As an alternative, we present our initial experience using a synthetic, off-the-shelf polyurethane scaffold for augmentation and reconstruction of segmental labral tissue loss or irreparable labral damage. Three patients aged 37–44 (two male, one female) with femoroacetabular impingement without associated dysplasia (Wiberg > 25°) or osteoarthritis (Tönnis <2) were included in this series. Labral reconstruction (one case) and augmentation (two cases) were performed using a synthetic polyurethane scaffold developed for meniscal substitution (Actifit®, Orteq Ltd, London, UK) and adapted to the hip. Clinical results were analysed with patient-reported outcomes (PROMs) using non-arthritic hip score (NAHS) and daily live activities hip outcome score (DLA HOS) and magnetic resonance images (MRI) at 2- and 4-year follow-up. Clinically improvement was seen in all PROMs at 4 years. The NAHS scores improved from 57.7 to 82.3 (50.9% improvement) and HOS from 59 to 79.3 (35.3% improvement). Last follow-up MRIs confirmed the presence of the scaffold; however, the scaffold signal was still hyperintense compared to native labrum. There was no shrinkage in any scaffold and no progression to hip osteoarthritis seen. Reconstruction or augmentation of segmental labral defects with a polyurethane scaffold may be an effective procedure. At 4 years after implantation, our small cases series resulted in improved hip joint function, reduced pain and scaffold preservation on follow-up imaging.

First Clinical Application of Polyurethane Meniscal Scaffolds with Mesenchymal Stem Cells and Assessment of Cartilage Quality with T2 Mapping at 12 Months

Background Complex meniscal lesions often require meniscectomy with favorable results in the short term but a high risk of early osteoarthritis subsequently. Partial meniscectomy treated with meniscal substitutes may delay articular cartilage degeneration. Purpose To evaluate the status of articular cartilage by T2 mapping after meniscal substitution with polyurethane scaffolds enriched with mesenchymal stem cells (MSC) and comparison with acellular scaffolds at 12 months. Methods Seventeen patients (18-50 years) with past meniscectomies were enrolled in 2 groups: (1) acellular polyurethane scaffold (APS) or (2) polyurethane scaffold enriched with MSC (MPS). Patients in the MPS group received filgrastim to stimulate MSC production, and CD90+ cells were obtained and cultured in the polyurethane scaffold. The scaffolds were implanted arthroscopically into partial meniscus defects. Concomitant injuries (articular cartilage lesions or cartilage lesions) were treated during the same procedure. Changes in the quality of articular cartilage were evaluated with T2 mapping in femur and tibia at 12 months. Results In tibial T2 mapping, values for the MPS group increased slightly at 9 months but returned to initial values at 12 months ( P > 0.05). In the APS group, a clear decrease from 3 months to 12 months was observed ( P > 0.05). This difference tended to be significantly lower in the APS group compared with the MPS group at the final time point ( P = 0.18). In the femur, a slight increase in the MPS group (47.8 ± 3.4) compared with the APS group (45.3 ± 4.9) was observed ( P > 0.05). Conclusion Meniscal substitution with polyurethane scaffold maintains normal T2 mapping values in adjacent cartilage at 12 months. The addition of MSC did not show any advantage in the protection of articular cartilage over acellular scaffolds ( P > 0.05).

3D-Printed Poly(ε-caprolactone) Scaffold Augmented With Mesenchymal Stem Cells for Total Meniscal Substitution: A 12- and 24-Week Animal Study in a Rabbit Model

Background: Total meniscectomy leads to knee osteoarthritis in the long term. The poly(ε-caprolactone) (PCL) scaffold is a promising material for meniscal tissue regeneration, but cell-free scaffolds result in relatively poor tissue regeneration and lead to joint degeneration. Hypothesis: A novel, 3-dimensional (3D)–printed PCL scaffold augmented with mesenchymal stem cells (MSCs) would offer benefits in meniscal regeneration and cartilage protection. Study Design: Controlled laboratory study. Methods: PCL meniscal scaffolds were 3D printed and seeded with bone marrow–derived MSCs. Seventy-two New Zealand White rabbits were included and were divided into 4 groups: cell-seeded scaffold, cell-free scaffold, sham operation, and total meniscectomy alone. The regeneration of the implanted tissue and the degeneration of articular cartilage were assessed by gross and microscopic (histological and scanning electron microscope) analysis at 12 and 24 weeks postoperatively. The mechanical properties of implants were also evaluated (tensile and compressive testing). Results: Compared with the cell-free group, the cell-seeded scaffold showed notably better gross appearance, with a shiny white color and a smooth surface. Fibrochondrocytes with extracellular collagen type I, II, and III and proteoglycans were found in both seeded and cell-free scaffold implants at 12 and 24 weeks, while the results were significantly better for the cell-seeded group at week 24. Furthermore, the cell-seeded group presented notably lower cartilage degeneration in both femur and tibia compared with the cell-free or meniscectomy group. Both the tensile and compressive properties of the implants in the cell-seeded group were significantly increased compared with those of the cell-free group. Conclusion: Seeding MSCs in the PCL scaffold increased its fibrocartilaginous tissue regeneration and mechanical strength, providing a functional replacement to protect articular cartilage from damage after total meniscectomy. Clinical Relevance: The study suggests the potential of the novel 3D PCL scaffold augmented with MSCs as an alternative meniscal substitution, although this approach requires further improvement before being used in clinical practice.