Magnetic Resonance Imaging and Functional Outcomes After a Polyurethane Meniscal Scaffold Implantation: Minimum 5-Year Follow-up

Purpose: To report the magnetic resonance imaging (MRI) and clinical outcomes at a minimum 5-year follow-up in a series of patients with postmeniscectomy syndrome and treated with a polyurethane scaffold. Methods: All consecutive patients operated on from September 2008 to February 2011 for either persistent medial or lateral joint line compartmental pain receiving a polyurethane scaffold due to a previous partial meniscus resection with a minimum 5-year followup were included. Functional scores (Knee Injury and Osteoarthritis Outcomes Score, International Knee Documentation Committee, Lysholm, and Tegner) were assessed preoperatively and at the last follow-up. The state of the scaffold as well as postoperative scaffold extrusion and the total remaining meniscal volume was also evaluated in MRI. Results: Thirty-two patients were included. The mean follow-up was 70.8 +/- 7.5 months. The functionality of the knees improved in all the scores used (P < .001) except for the Tegner score that stayed steady. Most of meniscal implants showed extrusion of 2.4 mm (95% confidence interval [ CI], 1.1-3.7) were smaller and a hyperintensity signal was seen in the MRI. Three scaffolds were resorbed at the last follow-up. The meniscal volume, determined by MRI, was 1.14 cm(3) (95% CI, 0.96-1.31) preoperatively and 1.61 cm(3) (95% CI, 1.43-1.7) at the last follow-up. No differences were presented. Conclusions: The use of a polyurethane meniscal scaffold in patients with a symptomatic meniscus deficit had a good functional outcome at 5 years after surgery. However, the implanted scaffolds did not present normal meniscal tissue with MRI, and the implant volume was considerably less than expected. The fact that most of patients included received different concomitant procedures during scaffold implantation introduces a degree of performance bias into the results.