No differences in clinical outcome between CMI and Actifit meniscal scaffolds: a systematic review and meta-analysis.

PURPOSE: To compare the results of two meniscal scaffolds, CMI and Actifit, for the treatment of partial meniscal lesions. METHODS: A systematic review was performed on the PubMed, Web of Science, Scopus, Embase, and Cochrane databases in January 2021, including randomized controlled trails (RCTs) and prospective and retrospective observational studies on the clinical results of meniscal scaffolds. A meta-analysis of the clinical results was performed; the rate of failures was recorded, as well as radiological results. The quality of the included studies was assessed with a modified Coleman Methodology Score (CMS). RESULTS: The search identified 37 studies (31 in the last 10 years): 2 RCTs, 5 comparative studies, 26 prospective and 4 retrospective series on a total of 1276 patients (472 CMI, 804 Actifit). The quality of evidence was generally low. An overall significant improvement in all clinical scores was documented for both scaffolds. The meta-analysis showed no differences between the two scaffolds in terms of patient reported outcome measures and activity level. The meta-analysis on the risk of failures documented a risk of failures of 7% in the CMI and of 9% in the Actifit group. CONCLUSIONS: There is a growing interest on the results of meniscal scaffolds, with most studies published recently. However, long-term data on the Actifit scaffold and high-level comparative studies are missing. Both CMI and Actifit offered good clinical results with a significant and comparable improvement in symptoms and function, and with a low number of failures over time. Accordingly, with the proper indication, their use may be encouraged in the clinical practice. LEVEL OF EVIDENCE: Level IV.

Biomechanical performance of the Actifit® scaffold is significantly improved by selection of irrigation fluid.

PURPOSE: Clinical reports on meniscal scaffolds seem promising, albeit relatively paucity exists regarding their biomechanical behavior. The aim of the study is to delineate the impact of differing suture materials and the type as well as the temperature of the irrigation fluid on the pull-out strength of a polyurethane meniscal scaffold (Actifit®). MATERIALS AND METHODS: 128 specimens were utilized with horizontal sutures and uniaxial load-to-failure testing was performed. We compared two different suture materials-polydioxanone (PDS) and non-absorbable, braided polyester sutures (NABP)-as well as two common irrigation fluids-lactated Ringer's and electrolyte-free, hypotonic Mannitol-Sorbitol. All specimens were further evaluated according to two different temperatures [room temperature (20 °C) and near-core body temperature (37 °C)]. RESULTS: Mean load-to-failure was 53.3 ± 6.5 N. There was no significant difference between the NABP and the PDS group. Ringer group showed a significantly higher load-to-failure compared to Purisole (P = .0002). This was equivalent for both PDS (P = .0008) and NABP sutures (P = .0008). Significantly higher failure loads could be established for the 37° group (P = .041); yet, this difference was neither confirmed for the PDS or in in the NABP subgroup. Only the subgroup using Purisole at 37° showed significantly higher failure loads compared to 20° (P = .017). CONCLUSIONS: This study underlines the potential to improve pull-out strength during implantation of an Actifit® scaffold by alteration of the type of irrigation fluid. Lactated Ringer solution provided the highest construct stability in regard to load-to-failure testing and should be considered whenever implantation of a polyurethane meniscal scaffold is conducted.

Midterm follow-up after implantation of a polyurethane meniscal scaffold for segmental medial meniscus loss: maintenance of good clinical and MRI outcome.

PURPOSE: The preservation of meniscal structure and function after segmental meniscal loss is of crucial importance to prevent early development of osteoarthritis. Implantation of artificial meniscal implants has been reported as a feasible treatment option. The purpose of this study was to assess the clinical and magnetic resonance imaging (MRI) results 4 years after implantation of a polyurethane scaffold for chronic segmental medial meniscus deficiency following partial medial meniscectomy. METHODS: Eighteen patients received arthroscopic implantation of an Actifit(®) polyurethane meniscal implant (Orteq Sports Medicine, London, UK) for deficiency of the medial meniscus. Patients were followed at 6, 12, 24, and 48 months. Clinical outcome was assessed using established patient-reported outcome scores (KOOS, KSS, UCLA Activity Scale, VAS for pain). Radiological outcome was quantified by MRI scans after 6, 12, 24, and 48 months evaluating scaffold morphology, tissue integration, and status of the articular cartilage as well as signs of inflammation. RESULTS: Median patient age was 32.5 years (range 17-49 years) with a median meniscal defect size of 44.5 mm (range 35-62 mm). Continuing improvement of the VAS and KSS Knee and Function Scores could be observed after 48 months compared to baseline, whereas improvement of the activity level according to UCLA continued only up to 24 months and decreased from there on. The KOOS Score showed significant improvement in all dimensions. MRI scans showed reappearance of bone bruises in two patients with scaffold extrusion. No significant changes in the articular cartilage could be perceived. CONCLUSION: Arthroscopic treatment for patients with chronic segmental meniscal loss using a polyurethane meniscal implant can achieve sustainable midterm results regarding pain reduction and knee function. LEVEL OF EVIDENCE: IV.

Evaluation of Remodeling and Extrusion of Polyurethane Meniscal Implants after Meniscus Reconstruction using Ultrasonography.

INTRODUCTION: Meniscal tears are among the most common indications for knee arthroscopy. Artificial polyurethane scaffolds have demonstrated efficacy in reducing pain and promoting the growth of normal meniscal tissue, with high absorption rates facilitating full tissue regeneration. AIMS: This study aimed to evaluate the remodeling of polyurethane meniscal implants post-reconstruction using ultrasonography. This imaging technique not only assesses changes in implant properties, such as echogenicity, but also the shape changes during functional examination. METHODS: The assessment of meniscal extrusion, comparing size at rest and under weight-bearing, is an indirect parameter that provides insight into the physical properties of the remodeling implant, with greater extrusion indicating reduced stiffness and inferior physical properties of the meniscus. Ultrasonography has the valuable advantage of allowing for assessment of the blood supply to the meniscus through Power Doppler imaging. RESULTS: The presence of vessels within the meniscal implants serves as evidence of ongoing remodeling. The study included 35 patients (13 female, 22 male; mean age 41.6 years, range 18-66) who underwent arthroscopic meniscal reconstruction with polyurethane implants, with an average time from surgery of 2.8 years (range 0.3-4.5 years). Results showed complete (29.7%), significant (45.9%), or moderate (16.2%) remodeling into natural meniscal tissue in 91.8% of the implants. CONCLUSION: The mean values of extrusion in the supine position and during 90-degree flexion were significantly greater in the operated limb (2.603) compared to the contralateral limb (1.978; t(35) = 2.442; P < 0.05). No significant differences in extrusion were found between the limbs in a standing position, indicating favorable physical properties of the polyurethane meniscal implants. Further ultrasonography studies of meniscal scaffolds are deemed relevant.

Meniscal polyurethane scaffold plus cartilage repair in post meniscectomy syndrome patients without malalignment improves clinical outcomes at mid-term follow-up.

BACKGROUND: The aim of this study is to report the mid-term follow-up results of a prospective cohort of patients who underwent a polyurethane (PU) meniscal scaffold implantation for post meniscectomy syndrome (PMS), without limb realignment procedures. METHODS: Prospective study in patients with PU meniscal scaffolds implanted during 2014-2016. Limb realignment procedures excluded. Clinical outcomes were prospectively evaluated pre-operatively and every year post-operatively using patient-reported outcome scores (KOOS, VAS, Lysholm and IKDC). Post-operative radiologic evaluation was done using 3.0 T magnetic resonance imaging (MRI). Meniscal scaffold extrusion, signal intensity, tibio-femoral cartilage degeneration progression and complications were analyzed. RESULTS: Fourteen patients with an average age of 25.8 years (range: 17-47) received a PU scaffold (8 lateral and 6 medial). Associated procedures were done in all patients, with an osteochondral allograft transplantation (OAT) being the most common. Mean follow up was 51.6 (range: 39-66) months. Post-operative mean clinical outcomes scores showed significantly improved results compared to the pre-operative scores. Lysholm scores increased from 62.4 to 80.2 (P = 0.0023), KOOS from 68.9 to 80 (P = 0.0083) and VAS for pain decreased from 5.3 to 3.1 (P = 0.0024). Average post-operative IKDC score was 67.7. There were 8 cases of complete extrusion (>3 mm). The mean extrusion value was 4.0 mm (range: 3-6 mm). Three patients showed signs of a ruptured meniscal scaffold. One patient showed progression of the cartilage degenerative process. CONCLUSION: The use of a PU scaffold, associated with other surgical procedures in the knee, especially chondral repair, had a significant improvement in clinical outcomes compared to the baseline status, at an average of 51.6 months follow-up in patients suffering from PMS. Although imaging results show a high proportion of implant extrusion, this does not appear to imply a worsening in clinical outcomes in the short term. LEVEL OF EVIDENCE: IV. Case series.

Meniscus Scaffolds for Partial Meniscus Defects.

The meniscus is a crucial player in knee joint homeostasis. Loss of meniscus tissue can result in early onset of clinical symptoms like pain and loss of function, and structural degeneration of the articular cartilage. In case of a symptomatic segmental defect of the medial or lateral meniscus, different innovative options using biological or synthetic scaffolds are now available to regenerate meniscuslike tissue, with the aim of allowing a satisfactory clinical improvement to patients. However, the role of any of these procedures in terms of chondroprotection is questionable, and the overall outcomes in the long term still can be improved.

Actifit® polyurethane meniscal scaffold: MRI and functional outcomes after a minimum follow-up of 5 years.

BACKGROUND: Implantation of the Actifit® polyurethane meniscal scaffold in patients who have pain after partial meniscectomy provides short-term pain relief and better function. But there is a lack of information about medium-term outcomes. The objective of this longitudinal study was to evaluate the MRI and functional outcomes after a minimum follow-up of 5 years. It was hypothesized that the results are stable over time. MATERIAL AND METHODS: Fifteen consecutive patients (8 men, 7 women; mean age 30 years, range 19-47, mean BMI 25) were enrolled in the study between February 2008 and January 2011. Five patients also underwent ACL reconstruction and one underwent mosaicplasty. Nine lateral and six medial Actifit® implants were evaluated prospectively before the surgery and at a minimum of 12, 24 and 60 months' follow-up using a visual analogue scale (VAS) for pain, the objective and subjective IKDC scores, radiological and MRI analysis with measurement of the ICRS score, Genovese score and extrusion. RESULTS: The mean follow-up was 6 years (range 5-8.1). Two patients were lost to follow-up. Three patients were re-operated at 7, 19 and 30 months because they had not improved functionally and the implant appeared damaged on MRI. Partial removal of the implant did not improve the functional outcomes (mean subjective IKDC pre- and post-revision: 37.0 vs. 34.9). Two patients were lost to follow-up. In intention to treat (13 cases), the pain (VAS) and subjective IKDC score were improved between the preoperative period and the last follow-up (5.46 vs. 2.92, P=0.007 and 51.2 vs. 66.1, P=0.05). In per protocol (10 cases, failures excluded), the pain (VAS) and subjective IKDC score were improved (5.3 vs. 1.9, P=0.0009; 49.6 vs. 75.4, P=0.002) along with the pain, daily activities and quality of life components of the KOOS (60.6 vs. 86.0, P=0.0008; 70.3 vs. 90.2, P=0.001; 42.7 vs. 71.0, P=0.0058). The functional scores were stable between months 12, 24 and 60. ICRS cartilage score and mean meniscal extrusion were unchanged at the last follow-up (1.6 vs. 1.6 and 2.41 vs. 2.79). In all patients, the meniscal implant had an intermediate signal and reduced size on MRI. DISCUSSION: Despite an abnormal MRI appearance suggesting the meniscal scaffold is not fully mature after 5 years, the functional scores and cartilage status are stable at this time point. However, the failure rate is still high and removing the implant in patients with poor function does not improve the outcome. TYPE OF STUDY: Prospective cohort study Level IV.

The magnetic resonance aspect of a polyurethane meniscal scaffold is worse in advanced cartilage defects without deterioration of clinical outcomes after a minimum two-year follow-up.

BACKGROUND: Meniscal scaffolding is thought to provide functional improvement and to prevent cartilage degeneration. Advanced chondral injuries might damage the scaffold structural properties. OBJECTIVE: To evaluate the influence of different degrees of articular chondral injuries on the imaging aspect of a polyurethane meniscal scaffold (Actifit®). METHODS: Fifty-four patients operated on with an Actifit® were studied. The status of the articular cartilage in the involved compartment was classified according to ICRS. The characteristics of the implant were evaluated in MRI with the Genovese score. Functional scores included WOMET, IKDC and Kujala scores. The Genovese score was correlated with the degree of chondral injury and functional results. RESULTS: The mean follow-up was 39 months (range 25-63). Additional procedures were performed in 69.5%. There were 19 patients without chondral injuries and 14 with grade 1, 10 with grade 3 and eight with grade 4 chondral lesions. The morphology and size of the implant on MRI scanning were worse with a higher degree of chondral injury (p=0.023). WOMET, IKDC and Kujala improved from 36.2SD ±7.6, 32.3SD ±13.5 and 39.2SD ±8.1 to 75.8SD ±12.9 (p=0.02), 75.5SD ±15.4 (p=0.03) and 85.6SD ±13.4 (0.042), respectively. There was no relationship between the severity of chondral injury and functional scores. CONCLUSIONS: Patients without chondral injuries showed a better MRI aspect of the polyurethane scaffold in terms of size and morphology. By optimizing biomechanics, in particular the implantation of a meniscal substitute, significant pain relief and functional improvement were observed after a minimum two-year follow-up. LEVEL OF EVIDENCE: Therapeutic case series; level 4.

Actifit® scaffold implantation: Influence of preoperative meniscal extrusion on morphological and clinical outcomes.

BACKGROUND: Meniscal substitutes have been suggested for the treatment of knee pain after partial meniscectomy. However, despite the partial nature of the initial meniscectomy, secondary extrusion of the substitute is common. The primary objective of this study was to evaluate morphological outcomes of meniscal substitute implantation and their potential associations with preoperative meniscal extrusion. HYPOTHESIS: Preoperative absolute meniscal extrusion in the coronal plane predicts poorer morphological and clinical outcomes. MATERIAL AND METHODS: Consecutive patients who received an Actifit(®) meniscal substitute between 2008 and 2011 were included prospectively. After 1 year and 2 years, the IKDC score and KOOS were determined and magnetic resonance imaging performed. The morphological evaluation consisted in measuring meniscal extrusion and cartilage coverage by the substitute in the coronal and sagittal planes. RESULTS: Twenty patients were included. Among them, 3 required subsequent removal of the substitute. The mean subjective IKDC score increased from 48.1 preoperatively to 56.4 after 2 years. Over the same period, the function/sports/recreational activities component of the KOOS improved significantly (42.9 vs. 55.0, P=0.04). Positive correlations between preoperative and 1-year values were demonstrated for both cartilage coverage in the coronal and the sagittal planes (P=0.03 and P=0.04, respectively) and coronal absolute meniscal extrusion (P=0.05). No significant differences were found between preoperative and 2-year values of cartilage coverage in the coronal and sagittal planes (P=0.38). There was a negative correlation linking preoperative meniscal extrusion in the coronal plane to 1-year cartilage coverage in the coronal and sagittal planes (P=0.01 and P=0.04, respectively). Preoperative absolute meniscal extrusion in the coronal plane correlated negatively with the subjective IKDC score after 1 year (P=0.02). DISCUSSION: Preoperative meniscal extrusion in the coronal plane strongly predicts clinical and morphological outcomes. Marked preoperative meniscal extrusion, even in a patient with symptoms after partial meniscectomy, should prompt an appraisal of whether allograft replacement may be more appropriate than a meniscal substitute. LEVEL OF EVIDENCE: IV, prospective study.

Actifit synthetic meniscal substitute: experience with 18 patients in Brest, France.

BACKGROUND: The management of post-meniscectomy pain is poorly standardised. Allogeneic transplantation may be appropriate in some patients after total meniscectomy. After partial meniscectomy, the synthetic meniscal substitute Actifit may constitute a valid option if the knee is stable or stabilised and aligned or re-aligned. The interconnected pore structure of Actifit promotes tissue regeneration from the meniscal wall. Arthroscopy is used to position the implant, which is then sutured to the remaining native meniscus using horizontal stitches and to the meniscal wall using vertical stitches. However, a burdensome programme of rigorous rehabilitation is required after Actifit implantation. HYPOTHESIS: We hypothesised that implantation of a meniscal substitute effectively alleviated pain without adversely affecting the knee. OBJECTIVES: To assess the intra-articular behaviour of Actifit and the outcomes of Actifit implantation in a prospective case-series of patients monitored using arthroscopy, pathology, and imaging studies, as well as the Lysholm score to assess clinical benefits on daily activities. MATERIALS AND METHODS: Between October 2009 and April 2012, 18 patients underwent Actifit implantation at the military hospital in Brest, France. All procedures were performed by the same surgeon, who had extensive experience with meniscal suturing. There were 13 males and 5 females aged 20 to 46 years. The medial meniscus was involved in 13 patients and the lateral meniscus in 5 patients. Actifit implantation was used alone in 6 patients and in combination with anterior cruciate ligament reconstruction and/or realignment osteotomy in 12 patients. All patients were followed-up for at least 2 years. RESULTS: The mean Lysholm score after 1 year was 92%, indicating excellent outcomes. Magnetic resonance imaging showed no damage to the implant or degeneration of the neighbouring cartilage. Histological examination of meniscal substitute biopsies taken 1 year after implantation showed polymer ingrowth by normal chondrocytes and fibrochondrocytes. The clinical and radiographic outcomes compared favourably with those seen after isolated procedures on bone or ligaments. DISCUSSION: Actifit has no deleterious effects on patients. The implant induces and promotes meniscal regeneration. Actifit constitutes a major addition to our therapeutic armamentarium. We provide convincing evidence that meniscal reconstruction can be highly beneficial in decreasing the risk of progression to knee osteoarthritis. LEVEL OF EVIDENCE: IV.