Polyurethane Meniscal Scaffold Research Articles

Fibronectin-coated polyurethane meniscal scaffolding supplemented with MSCs improves scaffold integration and proteoglycan production in a rabbit model.

The role of mesenchymal stem cells (MSC) in supporting the formation of new meniscal tissue in a meniscal scaffold is not well understood. The objective of this study was to assess the quality of the meniscal tissue produced in a fibronectin (FN)-coated polyurethane (PU) meniscal scaffold after a meniscal injury was made in an experimental rabbit model. Twelve New Zealand white rabbits were divided in two groups after performing a medial meniscectomy of the anterior horn. In group 1, the meniscal defect was reconstructed with a non-MSC supplemented FN-coated PU scaffold. On the other hand, the same scaffold supplemented with MSCs was used in group 2. The animals were sacrificed at 12week after index surgery. A modified scoring system was used for histological assessment. This new scoring (ranging from 0 to 15) includes a structural evaluation (meniscal scaffold interface and extracellular matrix production) and tissue quality evaluation (proteoglycan and type I-collagen content). The meniscal scaffold was found loose in the joint in three cases, corresponding to two cases in group 1 and 1 case in group 2. No differences were observed between the groups in terms of the total score (7.0 ± 0.9 vs. 9.4 ± 2.6, p = 0.09). However, differences were observed in group 2 in which 2 out of the 5 scored items, scaffold integration (1 ± 0.0 vs. 1.9 ± 0.6, p = 0.03) and proteoglycan production (1.2 ± 0.3 vs. 2.4 ± 0.2, p = 0.001). A trend to a higher production of Type I-Collagen production was also observed in group 2 (1.1 ± 0.4 vs. 1.4 ± 0.7, p = 0.05). In a rabbit model at 12weeks, the adhesion of MSCs to a FN-coated PU scaffold improves scaffold integration, proteoglycan production and the characteristics of the new meniscal-like tissue obtained when compared to a non-supplemented scaffold. This fact could be a major step toward improving the adhesion of the MSCs to meniscal scaffolds and, consequently, the obtention of better quality meniscal tissue.

Clinical Outcomes After Polyurethane Meniscal Scaffolds Implantation Remain Stable Despite a Joint Space Narrowing at 10-Year Follow-Up

To report the clinical outcomes, radiologic evolution, and survivorship of a series of patients affected by the postmeniscectomy syndrome and treated with a polyurethane scaffold at a minimum 10-year follow-up. In addition, the radiologic evolution of these patients was also assessed. All the patients operated on with a polyurethane meniscal scaffold implantation to treat postmeniscectomy syndrome from 2008 to 2011 were prospectively followed. Clinical evaluations and radiologic studies were assessed at the preoperative period, at 5-year follow-up, and at minimum 10-year follow-up. Clinical outcomes were based on patient-reported outcomes (e.g., the Knee injury and Osteoarthritis Outcome Score, International Knee Documentation Committee, Lysholm, and Tegner). Radiographical evaluation of the joint-space narrowing was done in the Rosenberg view. Failure was defined as patients who required surgery to remove the scaffold or those patients who needed surgery for a total or partial knee replacement. Twenty-one of 27 patients, with a mean age of 56 ± 9.8 years, were available for the final follow-up. The mean follow-up was 11.8 (range, 10-12.7) years. Six patients were lost to follow-up. All functional scores showed a significant improvement (P < .001) at the 5- and 10-year follow-up. The exception was the Tegner score, which remained stable. The joint-space width was maintained from the preoperative period (1.9 ± 1.2 mm) up to the 5-year follow-up (1.3 ± 1.5 mm, P= .3) and decreased by the last evaluation (0.6 ± 1.2 mm, P= .001) at the last follow-up. Two (9.5%) of 21 patients were converted to a total knee replacement during the study period. None of the other patients needed revision surgery during the study period. The polyurethane meniscal scaffold provides significant and stable pain relief over time and improved functional outcomes at a minimum of 10 years after surgery. However, degenerative changes progressed in the treated compartment, with a joint-space narrowing over the 10-year period. Level IV, retrospective case series.

Fibronectin-coating enhances attachment and proliferation of mesenchymal stem cells on a polyurethane meniscal scaffold.

IntroductionPartial meniscectomy is one of the most common surgical strategy for a meniscal injury, but sometimes, patients complain of knee pain due to an overload in the ablated compartment. In these cases, implantation of tissue engineering scaffold could be indicated. Currently, two commercial scaffolds, based on collagen or polycaprolactone-polyurethane (PCL-PU), are available for meniscus scaffolding. In short term follow-up assessments, both showed clinical improvement and tissue formation. However, long-term studies carried out in PCL-PU showed that the new tissue decreased in volume and assumed an irregular shape. Moreover, in some cases, the scaffold was totally reabsorbed, without new tissue formation.Mesenchymal stem cells (MSCs) combined with scaffolds could represents a promising approach for treating meniscal defects because of their multipotency and self-renewal. In this work, we aimed to compare the behaviour of MSCs and chondrocytes on a PCL-PU scaffold in vitro. MSCs express integrins that binds to fibronectin (FN), so we also investigate the effect of a FN coating on the bioactivity of the scaffold.MethodsWe isolated rabbit bone marrow MSCs (rBM-MSCs) from two skeletally mature New Zealand white rabbits and stablished the optimum culture condition to expand them. Then, they were seeded over non-coated and FN-coated scaffolds and cultured in chondrogenic conditions. To evaluate cell functionality, we performed an MTS assay to compare cell proliferation between both conditions. Finally, a histologic study was performed to assess extracellular matrix (ECM) production in both samples, and to compare them with the ones obtained with rabbit chondrocytes (rCHs) seeded in a non-coated scaffold.ResultsA culture protocol based on low FBS concentration was set as the best for rBM-MSCs expansion. The MTS assay revealed that rBM-MSCs seeded on FN-coated scaffolds have more cells on proliferation (145%; 95% CI: 107%–182%) compared with rBM-MSCs seeded on non-coated scaffolds. Finally, the histologic study demonstrated that rCHs seeded on non-coated scaffolds displayed the highest production of ECM, followed by rBM-MSCs seeded on FN-coated scaffolds. Furthermore, both cell types produced a comparable ECM pattern.ConclusionThese results suggest that MSCs have low capacity attachment to PCL-PU scaffolds, but the presence of integrin alpha5beta1 (FN-receptor) in MSCs allows them to interact with the FN-coated scaffolds. These results could be applied in the design of scaffolds, and might have important clinical implications in orthopaedic surgery of meniscal injuries.

Clinical application of polyurethane meniscal scaffold: A meta-analysis

ObjectiveIn patients with partial meniscus defect, the implantation of polyurethane meniscal scaffold has become a common method for the treatment of meniscus vascular entry and tissue regeneration. However, it is unclear whether polyurethane meniscal scaffold will yield better clinical and MRI results after surgery. This meta-analysis compared the clinical and MRI results of polyurethane meniscal scaffold in some patients with meniscus defects. MethodsBy searching PubMed, Embase, and Cochrane Library, a systematic review of studies evaluating the clinical outcomes of patients with polyurethane meniscal scaffold implantation. The search terms used are: “meniscus”, “meniscal”, “scaffold”, “Actifit” “polyurethane” and “implant”. The study was evaluated based on the patient's reported outcome score, accompanying surgery, and radiology results. Genovese scale was used to evaluate morphology and signal intensity, and Yulish score was used to evaluate the imaging performance of articular cartilage. ResultsThere were 16 studies that met the inclusion criteria, a total of 613 patients, and the overall average follow-up time was 41 months. The clinical scores at the final follow-up, such as VAS, IKDC, Tegner, and KOOS, were significantly improved compared with preoperatively. The MS, SI, and IIRMC scores evaluated in MRI showed no significant difference between preoperative and final follow-up. However, for AC (OR 0.34, 95% CI 0.11–1.00; P = 0.05) and AME (OR 0.08, 95% CI 0.03–0.22; P < 0.01), the final follow-up results were worse than preoperatively. ConclusionsThis meta-analysis found that compared with preoperative, the clinical effect of the final follow-up was significantly improved. However, MS, SI, and IIRMC in MRI parameters did not change significantly. In addition, the final follow-up results of AC and AME showed a deteriorating trend. Therefore, for patients with partial meniscus defects, polyurethane meniscal scaffold seem to be a viable option, and further research is needed to determine whether the deterioration of AC and AME is clinically relevant.

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

BackgroundThe 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. MethodsProspective 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. ResultsFourteen 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. ConclusionThe 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 evidenceIV. Case series.

Functional and magnetic resonance imaging outcome after polyurethane meniscal scaffold implantation following partial meniscectomy.

Prevention of the knee osteoarthritis following meniscectomy is implantation of an allotransplant or an artificial meniscus. We present retrospective study of our early results of the treatment using polyurethane meniscal scaffold. From 2016 to 2020, we implanted nine polyurethane scaffolds (Actifit) after partial meniscectomy, five males and four females, age 36 (16-47), BMI 26.7 (17.2-35.9) kg/m2. Functional status, activity, pain, and MRI were assessed. FU 20.8 (6-48.5) months, 35.2 (0-68) months from the meniscectomy to the implantation. The average implant length was 46.1 (35-60) mm, average number of sutures was 7.6 (5-10). Lysholm score before surgery was 61.7 (49-85), after the surgery 86.4 (62-95) with p 0.0045, Tegner activity score before meniscectomy was 5.8 (4-7), after 3.8 (2-5), and after the scaffold implantation 4.6 (3-7) with p 0.0488. Before surgery, VAS score was 3.1 (2-4), and after 7.7 (5-9) with p 0.0042. Pursuant to the Genovese classification, the last follow-up MRI showed a type 2 meniscal morphology in four cases and a type 3 in five cases. Seven patients had type 1 and two had type 2 signal intensity. On average, the absolute extrusion of a transplanted meniscus was 3.67mm, and the relative extrusion was 0.58mm. Extrusion progress was not detected. Significantly improved knee functionality, increased level of physical activity, and reduced pain. MRI analysis revealed the meniscal transplant morphology and volume loss, as well as its extrusion without progression.

Polyurethane scaffold implants for partial meniscus lesions: delayed intervention leads to an inferior outcome

The purpose of this study was to assess the clinical outcomes of the implantation of an aliphatic polyurethane scaffold for the treatment of partial loss of meniscal tissue at a mean follow-up of 36months. A retrospective review on prospectively collected data was performed on patients who underwent implantation of an aliphatic polyurethane-based synthetic meniscal scaffold. Patients were evaluated for demographics data, lesion and implant characteristics (sizing, type and number of meniscal sutures), previous and combined surgeries and complications. Clinical parameters were rated using NRS, IKDC subjective, Lysholm, KOOS, and Tegner activity score, both preoperatively and at final follow-up. Sixty-seven patients were evaluated at a mean follow-up of 36months (48 M and 19 F; mean age 40.8 ± 10.6years; mean BMI 25.4 ± 4.3). The scaffold was implanted on the medial side in 54 cases, and on the lateral one in 13. Forty-seven patients had undergone previous surgical treatment at the same knee and 45 required combined surgical procedures. All evaluated scores improved significantly from the baseline. Among possible prognostic factors, a delayed scaffold implantation had lower post-operative clinical scores: IKDC subjective (P = 0.049), KOOS Sport (P = 0.044), KOOS total (p = 0.011), and Tegner (P = 0.03) scores at follow-up. The polyurethane meniscal scaffold implantation led to a significant clinical benefit in a large number of patients. A delayed intervention correlated with worse results. IV.

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

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. 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 follow-up 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. Thirty-two patients were included. The mean follow-up was 70.8 ± 7.5months. 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 2.4mm (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 1.14cm3 (95% CI, 0.96-1.31) preoperatively and 1.61cm3 (95% CI, 1.43-1.7) at the last follow-up. No differences were presented. Theuse of a polyurethane meniscal scaffold in patients with a symptomatic meniscus deficit had a good functional outcome at 5years 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. Level IV, case series.

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

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®). 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)]. Mean load-to-failure was 53.3 ± 6.5N. 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). 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.

Similar clinical outcomes following collagen or polyurethane meniscal scaffold implantation: a systematic review.

The purpose of this systematic review is to evaluate the current literature in an effort to assess specific clinical outcomes following meniscal scaffold implantation using the two available scaffolds: Collagen Meniscal Implant (CMI) and the Actifit polyurethane meniscal scaffold. A systematic review was performed by searching PubMed, Embase, and Cochrane Library to find studies evaluating clinical outcomes of patients undergoing meniscal scaffold implantation. Search terms used were "meniscus", "meniscal", "scaffold", and "implant". Studies were evaluated based on scaffold type, treatment failure rates, patient-reported outcome scores, concomitant procedures, and radiological findings. Radiological findings were recorded using the Genovese scale to assess morphology and signal intensity and the Yulish score to assess articular cartilage. Nineteen studies (1 level I, 1 level II, 17 level IV evidence) were identified that met inclusion criteria, including a total of 658 patients (347 Actifit, 311 CMI). The overall average follow-up was 45 months. Treatment failure occurred in 9.9% of patients receiving the Actifit scaffold at a mean follow-up of 40 months and 6.7% of patients receiving CMI at a mean follow-up of 44 months (n.s.). However, the rate of failure ranged from 0 to 31.8% amongst the included studies with a variable definition of failure. Additionally, overlapping patients and presence of concomitant surgeries such as anterior cruciate ligament reconstruction (ACLR) and high tibial osteotomy (HTO) may have a significant influence on these results. Outcomes for the Visual Analog Scale (VAS) for pain, Lysholm knee score, and Tegner activity score improved from preoperatively to latest follow-up in both groups, while the Knee Injury and Osteoarthritis Outcome Score and International Knee Documentation Committee scores improved from preoperatively to latest follow-up for Actifit scaffold patients. Overall, patients receiving CMI scaffolds had higher grades for Genovese morphology and signal intensity when compared to Actifit scaffold patients. Patients undergoing meniscal scaffold implantation with either CMI or Actifit scaffold can both be expected to experience improvement in clinical outcomes when used in association with concomitant procedures such as ACLR and HTO. IV, systematic review.

Polyurethane meniscal scaffolds lead to better clinical outcomes but worse articular cartilage status and greater absolute meniscal extrusion.

Implantation of polyurethane (PU) meniscal scaffolds has become a popular procedure to provide a scaffold for vessel ingrowth and meniscal tissue regeneration in patients with partial meniscal defects. However, it is unclear whether PU meniscal scaffolds lead to better clinical and magnetic resonance imaging (MRI) outcomes post-operatively. This meta-analysis compared the clinical and MRI outcomes in patients with partial meniscal defects treated with PU meniscal scaffolds. This meta-analysis reviewed all studies that assessed Lysholm score, International Knee Documentation Committee (IKDC) score, visual analogue scale (VAS) for pain, Tegner score, Knee Injury and Osteoarthritis Outcomes Score (KOOS), articular cartilage (AC), absolute meniscal extrusion (AME), morphology and size (MS), signal intensity (SI) of meniscal implant, and interface of the implant-residual meniscus complex (IIRMC) in patients with partial meniscal defects treated with PU meniscal scaffolds. Eighteen studies were included in the meta-analysis. The proportion of patients who evaluated MS (OR 0.71, 95% CI 0.38-1.33; n.s.), SI (OR 1.07, 95% CI 0.53-2.18; n.s.), and IIRMC (OR 1.00, 95% CI 0.33-3.06; n.s.) did not differ significantly between baseline and final follow-up. However, AC (OR 0.31, 95% CI 0.11-0.84; P=0.02) and AME (OR 0.05, 95% CI 0.01-0.18; P<0.00001) worsened between baseline and final follow-up. Conversely, Lysholm score (95% CI -1.87 to -1.07; P<0.00001), IKDC score (95% CI -2.19 to -1.08; P<0.00001), VAS for pain (95% CI -2.29 to -1.07; P<0.00001), Tegner score (95% CI -0.76 to -0.15; P=0.003), and overall KOOS (95% CI -29.48 to -23.17; P<0.00001) were significantly greater at final follow-up when compared to baseline. This meta-analysis found no significant differences in the tested MRI parameters, including MS, SI, and IIRMC. However, AC and AME worsened between baseline and final follow-up. Conversely, patients treated with PU meniscal scaffolds showed significant functional improvement and pain relief when compared with baseline scores. Thus, PU meniscal scaffolds appear to be a viable alternative for patients with partial meniscal defects, although further studies are needed to determine whether worsened AC and AME are clinically relevant. In particular, precise measurement of PU meniscal scaffolds in combination with thorough investigation of the baseline articular cartilage status and meniscal defect size may be effective for pain relief or functional improvement in patients with PU meniscal scaffold implantation. III.

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

BackgroundImplantation 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 methodsFifteen 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. ResultsThe 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. DiscussionDespite 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 studyProspective cohort study Level IV.

Polyurethane-based cell-free scaffold for the treatment of painful partial meniscus loss.

The aim of this study was to document, at mid-term follow-up, the clinical and MRI outcome of a polyurethane-based cell-free scaffold implanted to treat painful partial meniscus loss. Eighteen consecutive patients were enrolled and treated with arthroscopic polyurethane meniscal scaffold implantation and, in case of other comorbidities, with concurrent surgical procedures: 16 patients (9 men and 7 women, mean age 45±13years, mean BMI 25±3, 12 medial and 4 lateral implants) were prospectively evaluated with the subjective and objective IKDC and the Tegner scores at 24, 36, 48, 60, and 72months of follow-up. Eleven patients were also evaluated by 1.5-T MRI at the final follow-up. The IKDC subjective score showed a significant improvement from baseline to 24months (45.6±17.5 and 75.3±14.8, respectively; p=0.02) and subsequent stable results over time for up to 72months (final score 75.0±16.8). The Tegner score improvement between pre-operative status and final follow-up was also significant (p=0.039). Nevertheless, the final score remained significantly lower than the pre-injury sports activity level (p=0.027). High-resolution MRIs documented the presence of abnormal findings in terms of morphology, signal intensity, and interface between the implant and the native meniscus. Implant extrusion and bone oedema at the treated compartment were also observed in most of the cases, even though no correlation was found between imaging findings and clinical outcome. The present study reports satisfactory clinical outcomes at mid-term follow-up after polyurethane-based meniscal cell-free scaffold implantation. The treatment was effective both in cases of isolated partial meniscal lesions and in complex cases requiring the combination with other surgical procedures. On the other hand, a high rate of altered MRI aspects was documented. However, no correlation was found between the altered imaging parameters and the overall positive clinical findings, thus supporting the use of this procedure to treat painful partial meniscus loss. Case series, Level IV.

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

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 4years after implantation of a polyurethane scaffold for chronic segmental medial meniscus deficiency following partial medial meniscectomy. 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 48months. 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 48months evaluating scaffold morphology, tissue integration, and status of the articular cartilage as well as signs of inflammation. Median patient age was 32.5years (range 17-49years) with a median meniscal defect size of 44.5mm (range 35-62mm). Continuing improvement of the VAS and KSS Knee and Function Scores could be observed after 48months compared to baseline, whereas improvement of the activity level according to UCLA continued only up to 24months 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. 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. 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

BackgroundMeniscal scaffolding is thought to provide functional improvement and to prevent cartilage degeneration. Advanced chondral injuries might damage the scaffold structural properties. ObjectiveTo evaluate the influence of different degrees of articular chondral injuries on the imaging aspect of a polyurethane meniscal scaffold (Actifit®). MethodsFifty-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. ResultsThe mean follow-up was 39months (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. ConclusionsPatients 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 evidenceTherapeutic case series; level 4.

Results of polyurethane implant for persistent knee pain after partial meniscectomy with a minimum of two years follow-up

PurposeTo present the results of a polyurethane meniscal scaffold implant in 10 patients with persistent pain after meniscectomy. MethodsProspective, descriptive study of ten patients who underwent arthroscopic implantation of a polyurethane meniscal scaffold. Functional, MRI, and radiography assessments were performed pre-operatively and at 6 months, 1 year, and a final follow-up at a minimum of two years. Clinical evaluation included Lysholm score, KOOS and VAS. The MRI morphology and signal intensity of the implant were evaluated according to the criteria of Genovese et al. ResultsStatistically significant differences were found between the mean Lysholm score before surgery (63.5 points) and that at 6 months (76.8 points) (p=.001), one year (83.3 points) (p<.001) and final follow-up (84.4 points) (p<.001).KOOS showed significant differences between before surgery (64.23 points), 6 months (73.66 points) (p=.001), one year (81.39 points) (p<.001) and final follow-up (83.34 points) (p<.001).The mean values for VAS were 5.7 points in the pre-operative evaluation, 3.6 points at 6 months follow-up (p<.001), 1.9 points at one year (p<.001), and 1.9 points at final follow-up (p<.001).Radiology showed degenerative changes in one case.In MRI, the size of the implant and the intensity of the MRI signal gradually decreased, but it never changed to that of a normal meniscus. ConclusionA significant improvement was found in all the clinical parameters 24 months after the surgery, except in one patient who underwent further surgery. The scaffold reduced its size and but never achieved an MRI image similar to that of a normal meniscus.The procedure proved to be safe and useful for the treatment of persistent pain after meniscectomy.

Resultados de un implante de poliuretano para el tratamiento del dolor persistente de rodilla tras meniscectomía parcial con un mínimo de dos años de seguimiento

PurposeTo present the results of a polyurethane meniscal scaffold implant in 10 patients with persistent pain after meniscectomy. MethodsProspective, descriptive study of ten patients who underwent arthroscopic implantation of a polyurethane meniscal scaffold. Functional, MRI, and radiography assessment was performed pre-operatively and at 6-months, 1-year, and a final follow-up at a minimum of two years. Clinical evaluation included Lysholm score, KOOS and VAS. The MRI morphology and signal intensity of the implant were evaluated according to the criteria of Genovese et al. ResultsStatistically significant differences were found between the mean Lysholm score before surgery (63.5 points), and that at 6 months (76.8 points) (p=.001), one year (83.3 points) (p<.001) and final follow-up (84.4 points) (p<.001).KOOS showed significant differences between before surgery (64.23 points), 6 months (73.66 points) (p=.001), one year (81.39 points) (p<.001) and final follow-up (83.34 points) (p<.001).The mean values for VAS were 5.7 points in the pre-operative evaluation, 3.6 points at 6 months-follow-up (p<.001), 1.9 points at one year (p<.001), and 1.9 points at final follow-up (p<.001).Radiology showed degenerative changes in one case.In MRI, the size of the implant and the intensity of the MRI signal gradually decreased, but it never changed to that of a normal meniscus. ConclusionA significant improvement was found in all the clinical parameters 24 months after the surgery, except in one patient who underwent furher surgery. The scaffold reduced its size and but never achieved an MRI image similar to that of a normal meniscus.The procedure proved to be safe and useful for the treatment of persistent pain after meniscectomy.

Erratum to: Improvement in outcomes after implantation of a novel polyurethane meniscal scaffold for the treatment of medial meniscus deficiency.

Erratum to: Improvement in outcomes after implantation of a novel polyurethane meniscal scaffold for the treatment of medial meniscus deficiency.

Improvement in outcomes after implantation of a novel polyurethane meniscal scaffold for the treatment of medial meniscus deficiency

Meniscal injury resulting in segmental loss of meniscal tissue is a major risk factor for the development of osteoarthritis. Tissue engineering strategies have provided scaffolds for meniscal regeneration in order to establish a treatment option for patients with limited opportunities for meniscal reconstruction. The purpose of this study was to assess the clinical and magnetic resonance imaging (MRI) results 2 years after implantation of a polyurethane scaffold for chronic segmental medial meniscus deficiency following partial medial meniscectomy. Eighteen patients were treated with arthroscopic implantation of an ActiFit(®) (Orteq Sports Medicine) polyurethane meniscal scaffold for meniscus deficiency of the medial meniscus. Patients were followed up at 6, 12, and 24 months. Clinical outcome was assessed using patient-reported outcome scores (KOOS, KSS, UCLA activity scale, VAS for pain). Radiological outcome was assessed using MRI at 6, 12, and 24 months by evaluating scaffold morphology, scaffold integration, and additional joint injury, as well as joint inflammation. Eighteen patients with a median age of 32.5 years (range 17-49) were enrolled. Statistically significant improvements were present in all patients, but one at 2 years compared to baseline in all categories. Complete resorption of the scaffold occurred in one patient representing a failure to treatment. MRI showed abnormal signal intensity of the scaffold when compared to residual meniscal tissue but without synovitis or joint inflammation. Extrusion of the scaffold was present in four patients. No correlation between scaffold extrusion and clinical outcome was observed. Arthroscopic implantation of a polyurethane meniscal scaffold in patients with chronic segmental medial meniscus deficiency is not only a safe procedure but leads to good clinical results at a 2-year follow-up. Scaffold extrusion did not appear to affect clinical outcome. IV.

Polyurethane scaffold for the treatment of partial meniscal tears. Clinical results with a minimum two-year follow-up.

to evaluate the safety and effectiveness of the polyurethane meniscal scaffold through clinical examination, MRI and arthroscopic second look, over a minimum two-year follow-up. between 2009 and 2011, 19 patients underwent meniscal scaffold implantation in our department (medial meniscus in 16 cases lateral meniscus in two cases, and bilateral in one case). All the patients were clinically evaluated preoperatively, and at 6, 12, and 24 months after surgery using Lysholm score, Tegner score, and VAS. Ten patients were studied with MRI, and nine patients were evaluated arthroscopically. no adverse reactions to the implant were observed. The clinical scores showed a significant improvement at 6 months and increased progressively over time. On MRI studies, the implants showed a clear hyperintense signal, sometimes irregular, and the chondral surface was preserved in all cases. At arthroscopic second look in the first months after surgery, the scaffold size was unchanged and the scaffold appeared light yellowish in color and well integrated into the surrounding tissues. At arthroscopic second look at 12 and 24 months the scaffold was found to have an irregular morphology and to be slightly reduced in size. polyurethane meniscal scaffold is a good alternative to a collagen scaffold, but a longer follow-up is needed to evaluate the scaffold degradation and chondral coverage. level IV, therapeutic case series.