Background. The meniscal deficient knee often exists in the setting of associated pathology including instability, malalignment and chondral injury. Meniscal allograft transplantation (MAT) is established to be a reliable option in restoring function and treating symptoms. The aim of this study was to establish the role of MAT as part of a staged approach to treatment of the previously menisectomised knee. Methods. This prospective study included all patients that underwent arthroscopic MAT at our institution between 2010 to 2017. Fresh frozen allograft was utilised using a soft tissue fixation technique. Further data was collected for index surgical procedures before and after MAT. Data for pre and post-operative Knee Injury and osteoarthritis outcome scores (KOOS), Tegner scores, graft survival, reoperation rates, patient satisfaction and MRI extrusion measurements were collected and details of any further surgical intervention and / or complications also documented. Results. Twenty seven MAT procedures were performed in 26 patients. Sixteen patients underwent lateral MAT and 11 patients medial. Ten patients underwent ACL reconstruction, three ACI and two, osteotomy in the pre-MAT phase. A further seven patients underwent ACI within the post-operative phase. The post-operative mean KOOS scores improved significantly in all subscales as did Tegner scores. Graft survival was 100%, satisfaction rate 92%, and mean meniscal extrusion 3.04mm. Post operatively, three patients required meniscal repair and a single patient partial menisectomy of graft. Two patients underwent arthroscopic arthrolysis following MAT. Conclusions. This series highlights the multifactorial profile of the meniscal deficient knee and the role of MAT as a safe and reliable technique in the staged and comprehensive biologic treatment available to minimise symptoms and maximise outcomes

INTRODUCTION. Meniscal tears are very common and treated surgically by suturing or partial or total meniscectomy. After meniscectomy, the tibiofemoral contact area is decreased whih leads to higher contact stresses associated with clinical symproms and a faster progression of tibiofemoral osteoarthritis. Besides meniscus allograft transplantation, artificial implants have been developed to replace the menisci after meniscectomy. AIM. We investigated the short- and medium-term clinical results and survivorship of two artificial meniscus implants used as a treatment for post-meniscectomy pain in young to middle-aged patients: the anchored polyurethane degradable Actifit® (2007–2013) and the non-anchored polycarbonate-urethane NUSurface® meniscal implants (2011–2013). PATIENTS AND METHODS. Sixty-seven Actifit were implanted in 67 patients with a mean age of 30.5 years (12 to 50) as a lateral meniscus replacement in 24 cases and medial in 43. Forty-one NUSurface were implanted as a medial meniscus replacement in 35 patients aged 31 to 61 at surgery. Clinical scores (KOOS, Lysholm, IKDC, VAS and EQ-5D) and MRI were obtained preoperatively and at 1, 2 and 5 years (if applicable) postoperatively. Complications and reinterventions were noted and cumulative implant survivorship computed. RESULTS. Seventeen Actifit had been removed at a mean of 22 months postop for persisting pain and/or extrusion of the implant on MRI. Three were converted to a Total Knee Arthroplasty (TKA), 7 replaced by a meniscal allograft and 7 were removed. The cumulative survivorship was 63.6% at 6 years. Forty-six patients with the Actifit in situ had a significant improvement of all clinical scores compared to preoperative scores (p<0.05) and were satisfied with the result. In the NUSurface group, 19 of the 41 implanted menisci had been removed at 2 to 26 months follow-up. Reasons for failure were radial tear or rupture of the meniscus in 7 cases, dislocation with or without tear in 4, synovitis and hydrops in 2 possibly related to synovial reaction to polymer particles, medial pressure caused by a too large size in 3 and persistent pain or OA evolution in 3. In 5 patients the implant was replaced by the same type artificial meniscus, unsuccessfully in 3. Besides, complications occurred in 32 patients including inflammation, effusion and squeaking. Nevertheless the KOOS, IKDC and VAS for pain were significantly improved at 12 months postoperatively (p<0.001). DISCUSSION. Short-term clinical evaluation of artificial meniscal replacement after meniscectomy showed an initial improvement of pain and knee function. However, both in the anchored degradable polyurethane meniscal implant group as in the non-anchored polycarbonate-urethane implant group the number of short-term failures was high and associated with important morbidity. The hard, non-degradable polycarbonate-urethane meniscal implant was torn or worn in 7 cases within 2 years postop. Three patients had synovial reactions possibly related to particulate debris. In conclusion, the currently available artificial meniscal transplants have a too high short-term failure rate to be advocated for widespread clinical use