Meniscal allograft transplantation after meniscectomy: clinical effectiveness and cost-effectiveness

Addressing meniscal deficiency part 1: An umbrella review of systematic reviews and meta-analyses on meniscal allograft transplantation

Purpose

Meniscal injuries are common in the young and active population. There is increasing utilization of surgical interventions like meniscal allograft transplantation (MAT) to restore the protective function of menisci following injury leading to meniscal deficiency. Extensive research and publications exist on the management of meniscal injury and the sequalae of meniscal deficiency. However, a comprehensive synthesis of the existing evidence through an umbrella review is lacking. This study aims to fill this gap by providing a current examination of the literature on MAT.

Methods

A comprehensive search was conducted in the MEDLINE, Embase and Scopus databases to identify relevant systematic reviews and meta-analyses. Studies were screened based on predefined inclusion and exclusion criteria. The quality of the included studies was assessed using the AMSTAR-2 tool.

Results

A total of 41 studies were included in the review, with most published within the last decade. The majority of studies (56.1%) received a 'Critically Low' confidence rating, 26.8% were rated as 'Low', and only 14.6% were rated as 'High' confidence. From the included studies, 51.2% reported on PROMs, with the Lysholm score being the most common. Transplant failure and reoperation rate were reported in 34.1% and 19.5% of studies respectively. Studies on MAT reported favourable short-term outcomes in terms of patient-reported outcome measures (PROMs) but were limited by the lack of randomized control trials and consistent comparison groups.

Conclusions

This umbrella review highlights an increase in interest in MAT but underscores the need for higher-quality reviews with standardized reporting and rigorous methodologies. Future research should focus on long-term outcomes, optimal surgical techniques, patient selection criteria and risk factors for transplant failure. There is also a need for more studies focusing on MAT in pediatric populations. Overall, this review provides a comprehensive assessment of the current state of research in MAT and identifies areas for improvement in future studies.

Level of Evidence

Level IV.

High failure rate but promising clinical performance after implantation of a flexible medial meniscus prosthesis at 1-year follow-up

PURPOSE

After unsatisfactory results in a first-in-human clinical investigation with an anatomically shaped medial meniscus prosthesis, the prosthesis and its fixation technique were altered. This interim analysis of a prospective single-arm clinical investigation aims to evaluate safety and clinical performance in a first-in-human study with the redesigned meniscus prosthesis system.

METHODS

Ten patients suffering from medial postmeniscectomy pain syndrome were treated with the meniscus prosthesis. Patient-reported outcome measures were obtained at baseline and at 6-week, 3-, 6-, and 12-month follow-up. Radiographs and magnetic resonance imaging scans were obtained to evaluate joint degeneration and prosthesis location.

RESULTS

The device alterations resolved the issues occurring with the previous design, but four prostheses were explanted after fixation failure or subluxation of the prosthesis. Five out of six patients who reached 1-year follow-up reported a clinically significant improvement of the knee injury and osteoarthritis outcome score pain subscale. Imaging revealed no adverse effects on joint degeneration.

CONCLUSION

The failure mechanisms that occurred with the previous design have been resolved, but the new fixation technique introduced new safety issues. Improvement of positioning and fixation techniques are considered essential future adaptations to reduce the risk of failure. The good clinical outcomes reported by the patients reaching 1-year follow-up indicate that the medial meniscus prosthesis is a potential solution for patients suffering from postmeniscectomy pain syndrome.

LEVEL OF EVIDENCE

Level II.

Recurrent patellar dislocation: personalised therapy or operative treatment? The REPPORT randomised trial protocol

INTRODUCTION

Recurrent patellar dislocation is a debilitating musculoskeletal condition, affecting mainly adolescents and adults under the age of 30. It can persist for many decades, causing pain and cartilage and soft-tissue damage, potentially leading to osteoarthritis. Recurrent patellar dislocation can be managed with physiotherapy or surgery. However, it is not known which treatment is most effective.

METHODS AND ANALYSIS

Recurrent Patellar Dislocation: Personalised Therapy or Operative Treatment (REPPORT) is a pragmatic, multicentre, two-arm, superiority, randomised controlled trial. It will compare the clinical and cost-effectiveness of an initial management strategy of personalised, phased and progressive rehabilitation, termed personalised knee therapy versus surgery for recurrent patellar dislocation.The trial's target sample size is 276 participants who will be recruited from approximately 20 sites across the UK. Participants will be randomly allocated to the two treatment groups via a central computer-based minimisation system. Treatment allocation will be in a 1:1 ratio, stratified by age, presence of patella alta and recruitment site.The primary outcome is participant-reported function using the Knee injury and Osteoarthritis Outcome 4-domain score at 18 months post randomisation. Health economic evaluation will be conducted from a healthcare system and personal social services perspective. Secondary outcome data including patellar instability, health utility, work/education status, satisfaction with social roles and treatment, health resource use and adverse events will be collected at 6, 12, 18 and 24 months. Analysis will be on an intention-to-treat basis and reported in-line with the Consolidated Standards of Reporting Trials statement.

ETHICS AND DISSEMINATION

The trial was approved by the East Midlands-Nottingham 2 Research Ethics Committee on 30 March 2023.Results will be disseminated via peer-reviewed publications, presentations at national and international conferences, in lay summaries, and using the REPPORT website and social media channels.

TRIAL REGISTRATION NUMBER

ISRCTN17972668.

The Current State of Meniscus Replacements

PURPOSE OF REVIEW

The field of meniscus replacement is changing continuously, with new devices emerging and others disappearing from the market. With the current tendency to preserve the knee joint, meniscus implants may become more relevant than ever. The purpose of this review is to provide an overview of the current state of partial and total meniscus replacements that have been developed beyond the academic phase. The available clinical and pre-clinical data is evaluated, and omissions are identified.

RECENT FINDINGS

Recent systematic reviews have shown a lack of homogenous clinical data on the CMI and Actifit meniscal scaffolds, especially regarding long-term performance without concomitant surgical interventions. Clinical studies on the medial total meniscus prostheses NUsurface and Artimis are ongoing, with the NUsurface being several years ahead. New techniques for meniscus replacement are rapidly developing, including the Artimis lateral meniscus prosthesis and the MeniscoFix 3D-printed scaffold. All evaluated clinical studies point towards improved clinical outcomes after implantation of partial and total meniscus replacements. Long-term data on survival and performance is of low quality for CMI and Actifit and is unavailable yet for NUsurface and Artimis. It is of major importance that future research focuses on optimizing fixation methods and identifying the optimal treatment strategy for each patient group. New techniques for total and partial replacement of the medial and lateral meniscus will be followed with interest.

Meniscal Transplant surgery or Optimised Rehabilitation full randomised trial (MeTeOR2): a study protocol

INTRODUCTION

Pain and disability after meniscectomy can be a substantial lifelong problem. There are few treatment options, especially for young people. Non-surgical management (rehabilitation) is an option but increasingly surgeons are performing meniscal allograft transplants (MATs) for these individuals. However, this is still an uncommon procedure, and availability and usage of MAT vary widely both in the UK and internationally. It is not known which treatment option is the most effective and cost-effective.

METHODS AND ANALYSIS

The Meniscal Transplant surgery or Optimised Rehabilitation trial is an international, multicentre, randomised controlled trial. The aim is to compare the clinical and cost effectiveness of MAT versus an optimised package of individualised, progressive, rehabilitation that we have called personalised knee therapy (PKT).Participants will be recruited from sites across the UK, Australia, Canada and Belgium. The planned 144 participants provide at least 90% power to detect a 10-point difference in the Knee injury and Osteoarthritis Outcome Score (KOOS4) at 24-months post randomisation (primary outcome). A prospectively planned economic evaluation will be conducted from a healthcare system and personal social services perspective. Secondary outcome data including health utility, occupational status, sports participation, mental well-being, further treatment, and adverse events will be collected at 3, 6, 12, 18, and 24 months. Analysis will be on an intention-to-treat basis and reported in-line with the Consolidated Standards of Reporting Trials statement.

ETHICS AND DISSEMINATION

The trial was approved by the London-Bloomsbury Research Ethics Committee on 19 August 2022 (22/LO/0327) and Northern Sydney Local Health District Human Research Ethics Committee, NSW, Australia on the 13 March 2023 (2022/ETH01890).Trial results will be disseminated via peer-reviewed publications, presentations at international conferences, in lay summaries and using social media as appropriate.This protocol adheres to the recommended Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) checklist.

TRIAL REGISTRATION NUMBER

ISRCTN87336549.

Serial ultrasonographic imaging can predict failure after meniscus allograft transplantation

Introduction

Treatment monitoring after meniscus allograft transplantation (MAT) is challenging. Ultrasonographic (US) imaging has been proposed as a modality that may allow for treatment monitoring after MAT, but has yet to be clinically validated for this purpose. The objective of this study was to assess the capabilities for serial US imaging during the first year after surgery to predict short-term MAT failure.

Methods

Patients who had undergone Meniscus-only or Meniscus-Tibia MAT for treatment of medial or lateral meniscus deficiency were prospectively evaluated by US imaging at various time points after transplantation. Each meniscus was evaluated for abnormalities in echogenicity, shape, associated effusion, extrusion and extrusion with weightbearing (WB).

Results

Data from 31 patients with a mean follow-up of 32 ± 16 (range, 12-55) months were analysed. MAT failure occurred in 6 patients (19.4%) at a median time point of 20 (range, 14-28) months with 4 (12.9%) converted to total knee arthroplasty. US imaging was effective for assessing MAT extrusion and imaging with WB demonstrated dynamic changes in MAT extrusion. US characteristics that were significantly associated with higher likelihood for MAT failure included abnormal echogenicity, localised effusion, extrusion with WB at 6 months, and localised effusion and extrusion with WB at 1 year.

Conclusions

US assessments of meniscus allografts at 6 months after transplantation can effectively determine risk for short-term failure. Abnormal meniscus echogenicity, persistent localised effusion and extrusion with weightbearing were associated with 8-15 times higher odds for failure, which occurred at a median of 20 months post-transplantation.

Signal intensity of lateral meniscal allografts deteriorates over time: a longitudinal MRI analysis during a minimum follow-up of 8 years

PURPOSE

To evaluate the serial change of magnetic resonance imaging (MRI) signal intensity (SI) of lateral meniscal allografts in a long-term period of > 8 years and to determine whether the SI change adversely affected clinical outcomes.

METHODS

Thirty-three lateral meniscal allograft transplantation (LMAT) patients with MRI taken > 8 years after surgery were included. The allograft was assessed using MRI at five serial time points (1, 2-4, 4-6, 6-8, and > 8 years after surgery), based on the following grading system: grade 1, globular increased SI not adjacent to the articular surface; grade 2, linear SI within the meniscus; and grade 3, increased SI extended to the articular surface. MRI evaluation was performed for three locations of the allograft (anterior horn, mid-body, and posterior horn), and the serial changes of allograft SI at each location were analyzed using the generalized estimating equation (GEE) with cumulative logit link function. The patients were classified according to SI change at each location (stationary group and deterioration group), and the two groups were compared in terms of clinical outcomes using the Lysholm score.

RESULTS

The mean follow-up duration was 9.2 ± 1.2 years. During that period, SI of the allograft deteriorated over time, regardless of the location (anterior horn, p = 0.034; mid-body, p = 0.002; posterior horn, p < 0.001). The amount of SI deterioration at each location of the graft differed with a borderline significance (p = 0.050, GEE), and the proportion of grade 3 SI was higher at the posterior horn (36.4%) than at the other locations at the last follow-up (p < 0.001, chi-square test). However, no significant differences in the Lysholm scores were found between the stationary group and the deterioration group at all locations.

CONCLUSION

SI of the meniscal allograft deteriorated over time at all locations during the long-term follow-up. Deterioration of the graft was more prominent at the posterior horn than at the other locations. SI deterioration did not adversely affect the clinical outcomes, which should be interpreted with caution, considering the small sample size of this study. In the prognosis of lateral MAT, SI deterioration at the posterior horn is a more determining factor than that at the other part of the allograft. Therefore, SI at the posterior horn needs to be examined with special concern.

LEVEL OF EVIDENCE

III.

Good clinical outcomes can be expected after meniscal allograft transplantation at 15 years of follow-up

PURPOSE

The aim of this study was to evaluate graft survivorship and report the functional and radiographic results of Meniscal allograft transplantation (MAT) throughout a minimum 15-year follow-up period.

METHODS

Fifty-one patients that had undergone an isolated MAT procedure during the period studied were included. The results were assessed with the Lysholm and Tegner scores as well as the Visual Analog Scale. Magnetic resonance imaging and a complete radiographic series were carried out to determine the degree of meniscal extrusion and joint space narrowing. A comparison was made between the radiological findings of the last follow-up, the 5-year mid-term follow-up and those from the preoperative period.

RESULTS

Thirty-eight patients were available for the final follow-up. The mean follow-up was 17.4 years. There were 23 (60.5%) medial menisci and 15 lateral menisci (39.4%). Meniscal extrusion increased from the 29.7% ± 14.9 obtained at the 5-year follow-up to the 72.5% ± 22.5 seen at the end of the follow-up (p = 0.0001). The joint space distance was almost unchanged from the initial evaluation (3.3 ± 1.5 mm) to the 5-year follow-up measurement (3.1 ± 1.7 mm, n.s.). However, it did decrease at the last follow-up (1.9 ± 1.5 mm, p < 0.05). The functional outcomes improved from the preoperative period to the mid-term follow-up and later worsened at the final follow-up. The mean preoperative Lysholm score at the initial follow-up was 61.5 ± 9.6, 86.9 ± 10.9 for the 5-year evaluation and stood at 77.4 ± 11.5 (p = 0.0001) at the final follow-up. Regarding the Tegner score, those pre-operative scores were compared to the ones at the last follow-up (median: 3; range 0-6 vs. 5.5; 3-6, respectively; p = 0.0001). The VAS went down from 6.6 ± 1.7 at the initial evaluation to 2.5 ± 1.9 at the final follow-up (p = 0.0001). The joint-space width remained unchanged from the initial evaluation (3.35 ± 1.5 mm) up to the 5-year follow-up measurement (3.1 ± 1.7 mm, n.s.). However, this joint-space distance had decreased by the last evaluation in the long-term follow-up (1.9 ± 1.4 mm, p < 0.05). Five patients (13.1%) presented with a MAT failure at 5 years, which was followed by extirpation of the meniscal graft. At the final follow-up, a total of 16 patients (42.1%) presented with a failure. At that time, there were 4 more MAT removals and seven patients that required a total knee replacement. The mean time to failure of the meniscal graft was 206.2 months ± 13.4 (18.0 years).

CONCLUSIONS

Meniscal allograft transplantation produces good functional results at a minimum 15-year follow-up. However, degenerative arthritis in the affected compartment progressed during that period.

LEVEL OF EVIDENCE

III.

The immediate meniscal allograft transplantation achieved better chondroprotection and less meniscus degeneration than the conventional delayed transplantation in the long-term

PURPOSE

The purpose of this study was to compare the long-term clinical and radiological outcomes between the immediate and delayed meniscus allograft transplantation (MAT).

METHODS

Nine menisci were transplanted immediately after total meniscectomy (immediate group, IM), and 10 menisci were delayed transplanted in patients with the median of 35 months (range 9-92 months) after total meniscectomy (delayed group, DE). Patient's subjective clinical outcomes including VAS, IKDC, Lysholm and Tegner scores as well as muscle strength measures were compared. Joint degeneration was evaluated by both radiographs to assess joint space width narrowing, Kellegren-Lawrence (KL) grade and MRI with T2 mapping sequences to quantitatively analyze both cartilage and meniscal allograft degeneration.

RESULTS

The median follow-up time was 10.8 years (range 10-14 years). The IKDC (IM vs DE, 89.8 vs 80.9, n.s.) and Lysholm scores (IM vs DE, 87.7 vs 78.0, n.s.) were close in two groups, while the IM group showed slightly lower VAS (IM vs DE, 0.2 vs 1.5, p = 0.031), higher Tegner score (IM vs DE, 7 vs 3.5 p = 0.021) and better quadriceps muscle strength. The IM group had less joint space narrowing (IM vs DE, 0.35 mm vs 0.71 mm, n.s.), less KL grade progression (IM vs DE, 0.6 vs 1.7, p = 0.041) on radiographs and less chondral lesions development on MRIs (Cartilage Degeneration Index, IM vs DE, 252 vs 2038, p = 0.025). All meniscal grafts exhibited degeneration by showing grade 3 signal on MRI, and 4 (4/9) in the IM group and 8 (8/10) cases in the DE group. The T2 value of cartilage and meniscal allograft in the IM group was close to that of the healthy control and was significantly lower than that of the DE group.

CONCLUSION

Compared to the conventional delayed MAT, the immediate MAT achieved better cartilage and meniscus protection in the long-term, while its superiority in patient-reported outcomes was limited.

LEVEL OF EVIDENCE

IV.

Effect of Preoperative Joint Space Width on Lateral Meniscal Allograft Transplantation: Outcomes at Midterm Follow-up

Background:

It remains unclear whether lateral joint space narrowing without severe cartilage loss before meniscal allograft transplantation (MAT) affects clinical outcomes and graft extrusion.

Hypothesis:

Patients with greater preoperative joint space narrowing would show more graft extrusion, more osteoarthritis progression, and worse clinical outcomes than would those with less narrowing.

Study Design:

Case-control study; Level of evidence, 3.

Methods:

We retrospectively evaluated 61 patients who underwent lateral MAT and had a minimum follow-up of 4 to 5 years. The median preoperative joint space width (JSW) on Rosenberg view radiographs was used to classify patients into those with less joint space narrowing (JSW ≥3 mm; group A) and greater joint space narrowing (JSW <3 mm; group B). We compared differences between groups in terms of graft extrusion and articular cartilage loss (modified Outerbridge grade ≥3) on 1-year postoperative magnetic resonance imaging (MRI) scans and changes in JSW and clinical outcomes at the last follow-up.

Results:

There were 31 patients in group A and 30 patients in group B; the mean follow-up time for all patients was 64.4 ± 10.3 months. All patients showed a significant preoperative to postoperative improvement in outcome scores (P < .001 for all). The mean preoperative JSW was 3.8 ± 0.9 mm in group A and 2.3 ± 0.4 mm in group B (P < .001). In group B, there was more graft extrusion on postoperative MRI scans (3.0 ± 0.9 vs 1.9 ± 0.6 mm, respectively; P < .001) and a higher proportion of patients with pathological graft extrusion at final follow-up (43.3% vs 12.9%, respectively; P = .011) compared with group A. At 1 year postoperatively, cartilage loss grade ≥3 was observed at the lateral femoral condyle in 3.2% and 20.0% of patients in groups A and B (P = .053), respectively, and at the lateral tibial plateau in 3.2% and 30.0% of patients (P = .006), respectively. There were moderate correlations between graft extrusion and preoperative absolute JSW (r = –0.471; P < .001) and preoperative relative JSW (r = –0.428; P = .001).

Conclusion:

Patients with less preoperative joint space narrowing had less graft extrusion and cartilage loss on 1-year postoperative MRI scans, as well as better radiological and clinical outcomes at midterm follow-up, compared with patients with greater preoperative narrowing.

Long sports career and satisfactory clinical outcomes after Meniscal Allograft Transplantation (MAT) in young professional athletes involved in strenuous sports

PURPOSE

To assess the return to sport rate of young professional athletes, to analyze their careers in terms of matches played and league participation over a minimum period of 6 years after Meniscal Allograft Transplantation (MAT), as well as to assess the long-term clinical subjective outcomes and satisfaction.

METHODS

Thirteen professional athletes (ten soccer and one basketball players, one fencer and one wrestler) with a mean age at surgery of 23.4 ± 4.0 underwent MAT (six medial, seven lateral). The time required to return to sport, post-operative performance level and the number of reoperations were evaluated. At an average follow-up of 9.0 ± 2.8 years, Lysholm, KOOS and Cincinnati scores were administered and collected.

RESULTS

Thirteen patients (100%) returned to sports practice after an average period of 11.8 ± 3.8 months. Nine athletes (69%) returned to sports at the same pre-injury level. Overall, 93%, 85%, 62% and 55% were active until the 3rd, the 5th, the 7th and the 9th season after MAT, respectively. Seven patients (54%) underwent a reoperation after MAT, where only two of them (15%) were related to graft problems (one meniscectomy and one graft suture). Of the ten athletes that completed subjective evaluation, the mean Lysholm score was 72 ± 15 (0% "Excellent", 10% "Good", 60% "Fair", 30% "Poor"). Of the athletes with lower scores, one suffered from patellar tendon rupture, one from post-operative infection and one from a previous femoral fracture. The mean Cincinnati knee score was 77 ± 18, while the average KOOS values were 60 ± 34 for sports.

CONCLUSION

Meniscal Allograft Transplantation (MAT) in young professional athletes involved in strenuous activities allowed all patients to return to pre-injury sport and in nearly 70% of cases at their pre-injury level. After five seasons following MAT, 85% of patients were still active or playing more than 20-30 matches per season. On the other hand, nearly 50% underwent at least one reoperation and only 70% of patients were rated as "Good", or "Fair" using the Lysholm score.

LEVEL OF EVIDENCE

IV.

Outcomes, Complications, and Reoperations After Meniscal Allograft Transplantation

Background:

Outcomes following meniscal allograft transplantation (MAT) are an evolving topic.

Purpose:

To review clinical outcomes in younger, previously active patients who underwent an isolated MAT or MAT plus any osteotomy. Concurrent surgeries, complications, and graft survivorship are presented.

Study Design:

Case series; Level of evidence, 4.

Methods:

Inclusion criteria included having undergone MAT with a minimum of 1 year of follow-up with at least 1 of the following patient-reported outcome (PRO) measures collected pre- and postoperatively: visual analog scale for pain, Knee injury and Osteoarthritis Outcome Score (KOOS), the Western Ontario and McMaster Universities Arthritis Index, the 36-Item Short Form Health Survey, and overall satisfaction. From patient records, we recorded descriptive data, side (medial/lateral), previous or concurrent procedures, perioperative complications, revisions, and conversion to arthroplasty. Two-factor analysis of variance (ANOVA) was used to test for differences in age and body mass index (BMI). A 2 × 2 chi-square test was used to determine if the spectrum of procedures performed on our study’s patient group was representative of the entire population. PRO results were analyzed using a multivariate ANOVA.

Results:

From a total of 91 eligible patients, 61 (63 knees) met our inclusion criteria. Mean presurgery age was 25.5 ± 9.2 years, and mean BMI was 26.7 (range, 18.5-38.4). At follow-up (mean, 4.8 years; range, 1.0-13.6 years) overall PROs were statistically and clinically improved at final follow-up ( P ≤ .003); effect sizes were moderate and large. KOOS Pain and KOOS Activities of Daily Living showed some main or interaction effects that were trivial or small. Patient satisfaction with the treatment was ≥7 out of 10 in 85% of patients. A minimum of 1 subsequent surgery for various concerns was necessary in 23% of the 93 knees. Graft survival in the included patients was 100%.

Conclusion:

Complications (conditions requiring at least 1 subsequent surgery) affected about one-quarter of the patients who underwent MAT. Nevertheless, MAT seemed to provide our patients with adequate pain relief and improved function.

Germany has a high demand in meniscal allograft transplantation but is subject to health economic and legal challenges: a survey of the German Knee Society

PURPOSE

To determine the current status and demand of meniscal allograft transplantation (MAT) in Germany among members of the German Knee Society (= Deutsche Kniegesellschaft; DKG).

METHODS

An online survey was conducted between May 2021 and June 2021 and sent to all members of the DKG. The survey questionnaire consisted of 19 questions to determine the demand and technical aspects of MAT among the participants and to identify areas of improvement in MAT in Germany.

RESULTS

Overall, 152 participants, 136 (89.5%) from Germany, 8 (5.3%) from Switzerland, 6 (4.0%) from Austria, and 2 (1.3%) from other countries completed the online survey, with the majority working in non-academic institutions. According to the regulations of the DKG, 87 (57.2%) participants were board certified as specialized knee surgeons and 97 (63.8%) worked primarily in the field of orthopedic sports medicine. MAT was considered clinically necessary in Germany by 139 (91.5%) participants. Patient age (83.6%), post-meniscectomy syndrome in isolated lateral (79.6%) and medial (71.7%) meniscus deficiency, and functional and athletic demands (43.4%) were the most important determinants to consider MAT in patients. Participants reported that reimbursement (82.9%), jurisdiction over the use of donor grafts (77.6%), and the availability of meniscal allografts (76.3%) are the main challenges in performing MAT in Germany. The most frequently used meniscal allograft types by 54 (35.5%) participants who had already performed MAT were fresh-frozen grafts (56.6%), peracetic acid-ethanol sterilized grafts (35.9%), and cryopreserved grafts (7.6%). Participants reported to perform suture-only fixation more often than bone block fixation for both medial (73.6% vs. 22.6%) and lateral (69.8% vs. 24.5%) MAT.

CONCLUSION

More than 90% of the responding members of the DKG indicated that MAT is a clinically important and valuable procedure in Germany. Reimbursement, jurisdiction over the use of donor grafts, and the availability of meniscal allografts should be improved. This survey is intended to support future efforts to facilitate MAT in daily clinical practice in Germany.

LEVEL OF EVIDENCE

Level V.

Autologous semitendinosus tendon graft could function as a meniscal transplant

PURPOSE

Meniscectomy results in poor knee function and increased risk for osteoarthritis. Meniscal allograft transplantation is not widely used due to costs and availability. The semitendinosus tendon (ST) has the potential to remodel and revascularize in an intraarticular environment, such as ACL reconstruction. The objective for this pilot study was to investigate whether the ST graft could function as a meniscal transplant.

METHODS

The ST was doubled and sutured with running sutures and pull-out sutures in each end. Bone tunnels were used for root anchorage and the graft was sutured with allinside, inside-out and outside-in technique. The pull-out sutures were fixed over a button. Partial weight bearing was allowed with limited range of motion in a brace for the first 6 weeks. Evaluation was assessed using clinical examination, radiology and patient reported outcome.

RESULTS

A total of seven patients have been included between January 2018 and June 2020. Six medial transplants and one lateral transplant were performed. Mean age was 29 years. Four patients had completed the 12-month follow-up. Improvements were noted for IKDC Global Score, KOOS pain subscale and Lysholm. MRI indicated that the transplant become more wedge-like with visible roots and minor protrusion.

CONCLUSIONS

Even though this is primarily a technical report the follow-up data indicate that the transplant survives and adapts in shape and capabilities to an original meniscus. There were no adverse events and the patients seem to improve in terms of pain and quality of life.

Comparative Evaluation of Synovial Multipotent Stem Cells and Meniscal Chondrocytes for Capability of Fibrocartilage Reconstruction

OBJECTIVE

Meniscus tissue is composed of highly aligned type I collagen embedded with cartilaginous matrix. This histological feature endows mechanical properties, such as tensile strength along the direction of the collagen alignment and endurance to compressive load induced by weight bearing. The main objective of this study was to compare the fibrocartilage construction capability of different cell sources in the presence of mechanical stimuli.

DESIGN

Synovial multipotent stem cells (SvMSCs) and meniscal chondrocytes (MCs) from immature and mature rabbits were maintained under similar conditions for comparative evaluation of growth characteristics and senescence tendency. The differentiation potential of cell sources, including fibrocartilage generation, were comparatively evaluated. To determine the capability of fibrocartilage generation, cultured cell sheets were rolled up to produce cable-form tissue and subjected to chondrogenic induction in the presence or absence of static tension.

RESULTS

Although SvMSCs showed superior cell growth characteristics during in vitro cell expansion, senescence-associated β-galactosidase expression was consistently higher, compared with MCs. MCs showed glycosaminoglycan (GAG)-rich matrix formation during default in vitro chondrogenesis. While application of static tension significantly reduced GAG production, MCs continued to show robust tissue growth. SvMSCs showed inferior chondrogenic differentiation and diminished tissue growth in the presence of static tension.

CONCLUSIONS

While SvMSCs produced fibrous tissue during default in vitro chondrogenesis, their fibrocartilage generation potential in the presence of static tension was significantly lower, compared with MCs. Our results support evaluation of cellular response to tensile stimulus as a decisive factor in determining the ideal cell source for fibrocartilage reconstruction.

An increasing trend of the number of meniscus allograft transplantation in Korea

PURPOSE

Meniscus allograft transplantation (MAT) can be performed to treat symptomatic patients with meniscus-deficient knees. However, the current epidemiologic status of MAT is unknown in many countries, including Korea. This study aimed to investigate the national trends of MAT in Korea which covers MAT procedures by the Korean national health insurance system.

METHODS

Information from the national database was acquired through the Korean Health Insurance Review and Assessment Service (HIRA) from 2010 to 2017. All patients encoded as MAT were included. The total number of MATs and their incidence per 100,000 persons were determined, and the results were stratified by age and sex.

RESULTS

The total number of MATs and their incidence per 100,000 persons per year were 369 and 0.77, respectively, in 2010, which increased to 826 and 1.72, respectively, in 2017. The number of MATs increased by 124% over 8 years. The peaks for the total number of MATs and their incidence were seen in patients in their 20 s in 2010, but in 2017, the peaks were observed in patients who were in their 40 s. MAT was performed more frequently in males (61%) than in females (39%) over the study period.

CONCLUSION

The total number of MATs and their incidence had increased by 124% between 2010 and 2017. The peak treatment age range for MAT changed from 20 years of age in 2010 to 40 years of age in 2017, and MAT was performed more frequently in males than in females.

LEVEL OF EVIDENCE

IV.

Biosynthetic scaffolds for partial meniscal loss: A systematic review from animal models to clinical practice

Acute or degenerative meniscus tears are the most common knee lesions. Meniscectomy provides symptomatic relief and functional recovery only in the short- to mid-term follow-up but significantly increases the risk of osteoarthritis. For this reason, preserving the meniscus is key, although it remains a challenge. Allograft transplants present many disadvantages, so during the last 20 years preclinical and clinical research focused on developing and investigating meniscal scaffolds. The aim of this systematic review was to collect and evaluate all the available evidence on biosynthetic scaffolds for meniscus regeneration both in vivo and in clinical studies. Three databases were searched: 46 in vivo preclinical studies and 30 clinical ones were found. Sixteen natural, 15 synthetic, and 15 hybrid scaffolds were studied in vivo. Among them, only 2 were translated into clinic: the Collagen Meniscus Implant, used in 11 studies, and the polyurethane-based scaffold Actifit®, applied in 19 studies. Although positive outcomes were described in the short- to mid-term, the number of concurrent procedures and the lack of randomized trials are the major limitations of the available clinical literature. Few in vivo studies also combined the use of cells or growth factors, but these augmentation strategies have not been applied in the clinical practice yet. Current solutions offer a significant but incomplete clinical improvement, and the regeneration potential is still unsatisfactory. Building upon the overall positive results of these "old" technologies to address partial meniscal loss, further innovation is urgently needed in this field to provide patients better joint sparing treatment options.

Potential of Melt Electrowritten Scaffolds Seeded with Meniscus Cells and Mesenchymal Stromal Cells

Meniscus injury and meniscectomy are strongly related to osteoarthritis, thus there is a clinical need for meniscus replacement. The purpose of this study is to create a meniscus scaffold with micro-scale circumferential and radial fibres suitable for a one-stage cell-based treatment. Poly-caprolactone-based scaffolds with three different architectures were made using melt electrowriting (MEW) technology and their in vitro performance was compared with scaffolds made using fused-deposition modelling (FDM) and with the clinically used Collagen Meniscus Implants^® (CMI^®). The scaffolds were seeded with meniscus and mesenchymal stromal cells (MSCs) in fibrin gel and cultured for 28 d. A basal level of proteoglycan production was demonstrated in MEW scaffolds, the CMI^®, and fibrin gel control, yet within the FDM scaffolds less proteoglycan production was observed. Compressive properties were assessed under uniaxial confined compression after 1 and 28 d of culture. The MEW scaffolds showed a higher Young’s modulus when compared to the CMI^® scaffolds and a higher yield point compared to FDM scaffolds. This study demonstrates the feasibility of creating a wedge-shaped meniscus scaffold with MEW using medical-grade materials and seeding the scaffold with a clinically-feasible cell number and -type for potential translation as a one-stage treatment.

In Vivo Kinematic Analysis of Lateral Meniscal Allograft Transplantation With Soft Tissue Fixation

Background:

Lateral meniscal deficiency increases the pivot shift in the knee, and although meniscal allograft transplantation (MAT) is a well-established procedure with satisfactory clinical results, biomechanical studies have failed to show whether this procedure is able to restore knee kinematics.

Purpose:

To assess, in vivo, the kinematic effect of lateral MAT in anterior cruciate ligament–intact knees, with a particular focus on the pivot-shift maneuver.

Study Design:

Controlled laboratory study.

Methods:

Enrolled in this study were 10 consecutive patients undergoing lateral MAT. A surgical navigation system was used to acquire and quantify the following variables: anterior-posterior displacement at 30° of flexion (AP30) and 90° of flexion (AP90), varus-valgus rotation at 0° of flexion (VV0) and 30° of flexion, and dynamic laxity on the pivot-shift test, which was determined through anterior displacement of the lateral tibial compartment (APlat) and posterior acceleration of the lateral tibial compartment during tibial reduction (ACC). Data from before and after MAT were compared.

Results:

From pre- to postoperatively, there was a significant decrease in tibial translation of 2.8 mm (43%; P = .005) for AP30 and 1.9 mm (38%; P = .018) for AP90 as well as a significant difference of 3.6° (64%; P = .001) for VV0. There was also a significant pre- to postoperative reduction in the pivot shift of 7.4 mm (39%; P = .021) for APlat and 302.9 mm/s² (75%; P = .005) for ACC.

Conclusion:

Lateral MAT improved knee kinematic parameters at time zero after surgery; the biomechanical effect of MAT was particularly evident during the pivot-shift maneuver.

Imaging of meniscal allograft transplantation: what the radiologist needs to know

Meniscal allograft transplantation is an emerging surgical option for younger patients with symptomatic meniscal deficiency, which aims to restore anatomic biomechanics and load distribution in the knee joint, and by so doing to potentially delay accelerated osteoarthritis. In this review article, we summarize the structure and biomechanics of the native meniscus, describe indications and procedure technique for meniscal allograft transplantation, and demonstrate the spectrum of expected postoperative imaging and role of imaging to identify potential complications.

Comparison of meniscal allograft transplantation techniques using a preclinical canine model

Meniscal allograft transplantation (MAT) can be a safe, effective treatment for meniscal deficiency resulting in knee dysfunction, leading to osteoarthritis (OA) without proper treatment with 5-year functional success rates (75%-90%). While different grafts and techniques have generally proven safe and effective, complications include shrinkage, extrusion, progression of joint pathology, and failure. The objective of this study was to assess the functional outcomes after MAT using three different clinically-relevant methods in a preclinical canine model. The study was designed to test the hypothesis that fresh meniscal-osteochondral allograft transplantation would be associated with significantly better function and joint health compared with fresh-viable or fresh-frozen meniscus-only allograft transplantations. Three months after meniscal release to induce meniscus-deficient medial compartment disease, research hounds (n = 12) underwent MAT using meniscus allografts harvested from matched dogs. Three MAT conditions (n = 4 each) were compared: frozen meniscus-fresh-frozen meniscal allograft with menisco-capsular suture repair; fresh meniscus-fresh viable meniscal allograft (Missouri Osteochondral Preservation System (MOPS)-preservation for 30 days) with menisco-tibial ligament repair; fresh menisco-tibial-fresh, viable meniscal-tibial-osteochondral allografts (MOPS-preservation for 30 days) with menisco-tibial ligament preservation and autogenous bone marrow aspirate concentrate on OCA bone. Assessment was performed up to 6 months after MAT. Pain, comfortable range of motion, imaging, and arthroscopic scores as well histological and cell viability findings were superior (P < .05) for the fresh menisco-tibial group compared with the two other groups. Novel meniscal preservation and implantation techniques with fresh, MOPS-preserved, viable meniscal-osteochondral allografts with menisco-tibial ligament preservation appears to be safe and effective for restoring knee function and joint health in this preclinical model. This has the potential to significantly improve outcomes after MAT.

MR variability of collagen meniscal implant remodelling in patients with good clinical outcome

PURPOSE

Collagen meniscal implants (CMI) have variable imaging findings on MRI and it remains ambiguous, if alterations may be present in asymptomatic patients. The aim was, to evaluate MR morphological characteristics and volume of CMI in the early, mid- and long-term follow-up.

METHODS

Fifty-seven patients (mean age, 43.6±11 years; 41 male/16 female) with good clinical outcome (subjective visual analogue scale for satisfaction < 2 and a Lysholm-score ≥ 84) after CMI were assessed retrospectively using MRI 1, 2 and 3-8 years postoperatively. CMI morphology, signal intensity (SI), homogeneity and size were assessed and a meniscal score was calculated. Chondral defects and bone marrow edema pattern were reported and summarized in a chondral score. Meniscal extrusion and volume were evaluated. Intra- and inter-reader reliabilities were calculated. Spearman and partial correlations were used (p < 0.05).

RESULTS

One year postoperatively, the CMI varied in size [10% (4/40) normal, 30% (12/40) small, 60% (24/40) hypertrophic] and was hyperintense and inhomogeneous in all patients. At long-term follow-up, the size of CMI decreased [6% (1/17) resorbed, 18% (3/17) normal, 41% (7/17) small, 35% (6/17) hypertrophic]. The SI of the CMI changed to normal in only 13% (2/16). The majority was still hyperintense [87% (14/16)]. Less meniscal extrusion was present in the follow-up [71% (11/16) versus initially 93% (37/40)]. The meniscal score improved significantly (ρ = 0.28). Over time, full-thickness femoral chondral defects were increasingly present [65% (10/17) versus initially 33% (13/40)] and the chondral score worsened significantly (p = 0.017).

CONCLUSION

Abnormal and inhomogeneous SI and irregular margins of the early postoperative CMI on MRI are findings seen in patients with good clinical results and should not necessarily be overcalled when reporting MRI. These features tend to decrease over time.

LEVEL OF EVIDENCE

IV.

Large chondral defect not covered by meniscal allograft is associated with inferior graft survivorship after lateral meniscal allograft transplantation

PURPOSE

This study aimed to evaluate graft survivorship according to the size and location of chondral defects and its effect on clinical outcomes after meniscal allograft transplantation (MAT). It was hypothesized that large chondral defects would be associated with inferior outcomes.

METHODS

Patients who underwent lateral MAT with fresh-frozen allografts between 2007 and 2016 were retrospectively reviewed. The inclusion criteria were patients with femoral or tibial chondral defects (International Cartilage Repair Society grade 4) who were followed up more than 2 years with 3.0-T magnetic resonance imaging (MRI) scans. Maximal lesion diameter and location were assessed on MRI. The patients were divided into two groups, with chondral defects of < 3 and ≥ 3 cm² on the tibial side. Graft survivorship was compared between the two groups. Graft failure was defined as revisional MAT, meniscal tear or meniscectomy greater than one-third of the allograft on MRI. Clinical outcomes were evaluated using the modified Lysholm score.

RESULTS

Twenty-eight knees in 26 patients (mean age 37.4 ± 10.3 years) with a mean follow-up of 3.6 ± 1.0 (range 2.0-5.4) years were identified. Nineteen knees in 17 patients had both femoral and tibial chondral defects, 7 knees in 7 patients had only femoral chondral defects, and 2 knees in 2 patients had only tibial chondral defects. The mean preoperative femoral and tibial chondral defect sizes were 1.7 ± 1.2 and 3.0 ± 1.4 cm², respectively. Among the seven graft failures, no graft failure occurred in the cases with tibial chondral defects of < 3 cm². Tibial chondral defects of ≥ 3 cm² were significantly associated with graft failure (P = 0.004; odds ratio 28.3; 95% confidence interval 2.5-4006.7). Defects of < 3 cm² were located primarily in the posterior aspect of the lateral tibial plateau, and most lesions were covered by allograft (7/9, 77.8%). The modified Lysholm scores significantly improved irrespective of chondral defects size (P < 0.001).

CONCLUSIONS

Larger chondral defects, more than 3 cm² on the tibial side, were associated with inferior graft survivorship but did not influence the clinical outcomes after MAT at the 3.6-year follow-up. Chondral defect location was associated with defect size.

LEVEL OF EVIDENCE

IV.

The menisci and articular cartilage: a life-long fascination

The menisci and articular cartilage of the knee have a close embryological, anatomical and functional relationship, which explains why often a pathology of one also affects the other.

Traumatic meniscus tears should be repaired, when possible, to protect the articular cartilage.

Traumatic articular cartilage lesions can be treated with success using biological treatment options such as microfracture or microdrilling, autologous chondrocyte transplantation (ACT), or osteochondral transplantation (OCT) depending on the depth and area of the lesion.

Degenerative cartilage and meniscus lesions often occur together, and osteoarthritis is already present or impending. Most degenerative meniscus lesions should be treated first conservatively and, after failed conservative treatment, should undergo arthroscopic partial meniscus resection. Degenerative cartilage lesions should also be treated conservatively initially and then surgically; thereby treating the cartilage defect itself and also maintaining the axis of the leg if necessary.

Tears of the meniscus roots are devastating injuries to the knee and should be repaired e.g. by transtibial re-fixation.

The clinical role of ‘ramp’ lesions of the meniscus is still under investigation.

Cite this article: EFORT Open Rev 2020;5:652-662. DOI: 10.1302/2058-5241.5.200016

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

PURPOSE

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.

METHODS

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.

RESULTS

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 3.67 mm, and the relative extrusion was 0.58 mm. Extrusion progress was not detected.

CONCLUSION

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.

An Up-to-Date Review of the Meniscus Literature: A Systematic Summary of Systematic Reviews and Meta-analyses

Background:

A large number of systematic reviews and meta-analyses regarding the meniscus have been published.

Purpose:

To provide a qualitative summary of the published systematic reviews and meta-analyses regarding the meniscus.

Study Design:

Systematic review; Level of evidence, 4.

Methods:

A systematic search of all meta-analyses and systematic reviews regarding the meniscus and published between July 2009 and July 2019 was performed with PubMed, CINAHL, EMBASE, and the Cochrane database. Published abstracts, narrative reviews, articles not written in English, commentaries, study protocols, and topics that were not focused on the meniscus were excluded. The most pertinent results were extracted and summarized from each study.

Results:

A total of 332 articles were found, of which 142 were included. Included articles were summarized and divided into 16 topics: epidemiology, diagnosis, histology, biomechanics, comorbid pathology, animal models, arthroscopic partial meniscectomy (APM), meniscal repair, meniscal root repairs, meniscal allograft transplantation (MAT), meniscal implants and scaffolds, mesenchymal stem cells and growth factors, postoperative rehabilitation, postoperative imaging assessment, patient-reported outcome measures, and cost-effectiveness. The majority of articles focused on APM (20%), MAT (18%), and meniscal repair (17%).

Conclusion:

This summary of systematic reviews and meta-analyses delivers surgeons a single source of the current evidence regarding the meniscus.

Comparing Meniscectomy and Meniscal Repair: A Matched Cohort Analysis Utilizing a National Insurance Database

BACKGROUND

Meniscal repair leads to improved patient outcomes compared with meniscectomy in small case series.

PURPOSE

To compare the reoperation rates, 30-day complication rates, and cost differences between meniscectomy and meniscal repair in a large insurance database.

STUDY DESIGN

Cohort study; Level of evidence, 3.

METHODS

A national insurance database was queried for patients who underwent meniscectomy (Current Procedural Terminology [CPT] code 29880 or 29881) or meniscal repair (CPT code 29882 or 29883) in the outpatient setting and who had a minimum 2-year follow-up. Patients without confirmed laterality and patients who underwent concomitant ligament reconstruction were excluded. Reoperation was defined by ipsilateral knee procedure after the index surgery. The 30-day postoperative complication rates were assessed using the International Classification of Diseases, 9th Revision, Clinical Modification codes. The cost of the procedures per patient was calculated. Propensity score matching was utilized to create matched cohorts with similar characteristics. Statistical comparisons of cohort characteristics, reoperations, postoperative complications, and payments were made. All P values were reported with significance set at P < .05.

RESULTS

A total of 27,580 patients (22,064 meniscectomy and 5516 meniscal repair; mean age, 29.9 ± 15.1 years; 41.2% female) were included in this study with a mean follow-up of 45.6 ± 21.0 months. The matched groups were similar with regard to characteristics and comorbidities. There were significantly more patients who required reoperation after index meniscectomy compared with meniscal repair postoperatively (5.3% vs 2.1%; P < .001). Patients undergoing meniscectomy were also significantly more likely to undergo any ipsilateral meniscal surgery (P < .001), meniscal transplantation (P = .005), or total knee arthroplasty (P = .001) postoperatively. There was a significantly higher overall 30-day complication rate after meniscal repair (1.2%) compared with meniscectomy (0.82%; P = .011). The total day-of-surgery payments was significantly higher in the repair group compared with the meniscectomy group ($7094 vs $5423; P < .001).

CONCLUSION

Meniscal repair leads to significantly lower rates of reoperation and higher rates of early complications with a higher total cost compared with meniscectomy in a large database study.

Functional and anatomical outcomes of single-stage arthroscopic bimeniscal replacement

BACKGROUND

Meniscal replacement by an allograft or scaffold has been proven effective in patients with post-meniscectomy pain syndrome. Replacement of both menisci is a rarely performed procedure about which little is known. The primary objective of this work was to assess the functional outcomes of arthroscopic bimeniscal replacement. The secondary objectives were to evaluate meniscal healing and the time-course of cartilage lesions.

HYPOTHESIS

Single-stage arthroscopic bimeniscal replacement provides good functional and anatomical outcomes, similar to those seen after replacement of a single meniscus, in adults with post-meniscectomy pain syndrome.

MATERIAL AND METHODS

Five patients received regular follow-up after single-stage arthroscopic bimeniscal replacement by an allograft and/or substitute, with or without concomitant anterior cruciate ligament reconstruction. Median follow-up was 30 months (range, 24-68 months). Radiographs and magnetic resonance imaging scans of the knee obtained before surgery and at last follow-up were evaluated. The following parameters were recorded: KOOS and IKDC score, knee osteoarthritis, knee alignment, condition of the cartilage, healing of the meniscal replacement material, meniscal extrusion, and other complications.

RESULTS

Allografts were used to replace both menisci in 3 patients, whereas 2 patients received a lateral allograft and a medial scaffold. The median subjective IKDC score was 83.9 (range, 55.1-94.3) and the median objective IKDC score was B (range, A-C). The median global KOOS was 85.7 (range, 65.7-92.3). Extrusion occurred for one medial and two lateral menisci.

CONCLUSION

Bimeniscal replacement by an allograft and/or substitute provides good short-term functional and anatomical outcomes. Nevertheless, this procedure is warranted only in highly selected patients.

LEVEL OF EVIDENCE

IV, retrospective study.