A biodegradable polyurethane scaffold was designed to fulfill a challenging clinical need in the treatment of patients with painful, irreparable partial meniscal defects.
The use of an acellular polyurethane scaffold for new tissue generation in irreparable, partial meniscal defects provides both midterm pain relief and improved functionality.
Case series; Level of evidence, 4.
A total of 44 patients with irreparable, partial meniscal defects (29 medial and 15 lateral) were implanted with a polyurethane scaffold in a prospective, single-arm proof-of-principle study with a minimum 5-year follow-up. Clinical outcomes were measured with the visual analog scale (VAS) for pain, International Knee Documentation Committee (IKDC), and Knee injury and Osteoarthritis Outcome Score (KOOS) at baseline and at 2- and 5-year follow-up. Magnetic resonance imaging (MRI) was used to evaluate the meniscal implant and cartilage status of the index compartment. Kaplan-Meier time-to-treatment failure distributions were also performed. Removal of the scaffold, conversion to a meniscal transplant, or unicompartmental/total knee arthroplasty was used as endpoints.
Seven patients were lost to follow-up (15.9%). The patients who participated in this study showed significant clinical improvement after surgery (mean [±SD] at baseline, 2 years, and 5 years: 56.2 ± 21.6, 24.6 ± 22.7, and 19.3 ± 26.9, respectively [VAS]; 206.5 ± 79.7, 329.8 ± 108.9, and 333.6 ± 112.2, respectively [total KOOS]). MRI of the scaffolds showed a smaller sized implant when compared with the native meniscus with an irregular surface at 2- and 5-year follow-up. A stable cartilage status of the index compartment at 5-year follow-up was demonstrated in 46.7% of patients compared with the baseline status. During the follow-up period, 62.2% of the implants survived. At final follow-up, 66.7% of the medial scaffolds were still functioning versus 53.8% of the lateral scaffolds.
A polyurethane meniscal implant can improve knee joint function and significantly reduce pain in patients with segmental meniscus deficiency up to 5 years after implantation. A stable cartilage status of the index compartment at 5-year follow-up was demonstrated in 46.7% of patients, calling into question the chondroprotective ability of the implant. In addition, a relatively high failure rate was noticed. Long-term and randomized controlled studies are mandatory to confirm the initial results and the reliability of this procedure.