Allograft Meniscus Transplantation: A Current Review:

TWO TO 14 YEAR OUTCOMES OF COMBINED MENISCAL ALLOGRAFT TRANSPLANTATION WITH ANTERIOR CRUCIATE LIGAMENT RECONSTRUCTION: A SYSTEMATIC REVIEW

PURPOSE

To evaluate the clinical outcomes of anterior cruciate ligament reconstruction (ACLR) with meniscal allograft transplantation (MAT) through systematic review of current available evidence.

METHODS

A systematic database search of PubMed, Embase, Web of Science and CINAHL was performed from inception up to 7 December 2021 in accordance with the Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA). Follow-up studies (inception cohort studies/non-randomized controlled trials/retrospective cohort studies) and case series that had more than 10 people published in English, which involved patients who underwent a combination of ACLR and MAT were included. Quality of these studies were appraised using the Cochrane Risk Of Bias In Non-randomized Studies of Interventions (ROBINS-I) tool. Systematic review of International Knee Documentation Committee (IKDC), Lysholm and Tegner activity scores were conducted.

RESULTS

Seven studies involving 363 patients were included. The average mean follow up time was 4.08 years, ranging from 1.75 to 14 years. All studies used the Lysholm Knee Scoring system to report clinical outcomes, while two studies and four studies used the IKDC Questionnaire and Tegner activity scale respectively to measure clinical outcomes post-operatively. Comparing postoperative to pre-operative scores, we found an improvement above the minimal clinically important difference (MCID) for the Lysholm (Mean Difference (MD) range= 16.00 to 26.10) and Tegner activity scores (MD range = 1.50 to 1.90). All but one study reported an increase above the MCID for IKDC scores post-op (MD range= 5.60 to 23.00).

CONCLUSIONS

Combined MAT and ACLR have good two to 14 year clinical outcomes post operatively and is an optimal procedure for patients with concurrent ACL injuries with irreparable meniscus injuries. More prospective studies and studies evaluating outcome differences between concurrent ACLR with MAT and staged ACLR with MAT should be conducted.

LEVEL OF EVIDENCE

IV, systematic review and/or meta-analysis of studies with Levels I to IV.

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.

Meniscal allograft transplants and new scaffolding techniques

Clinical management of meniscal injuries has changed radically in recent years. We have moved from the model of systematic tissue removal (meniscectomy) to understanding the need to preserve the tissue.Based on the increased knowledge of the basic science of meniscal functions and their role in joint homeostasis, meniscus preservation and/or repair, whenever indicated and possible, are currently the guidelines for management.However, when repair is no longer possible or when facing the fact of the previous partial, subtotal or total loss of the meniscus, meniscus replacement has proved its clinical value. Nevertheless, meniscectomy remains amongst the most frequent orthopaedic procedures.Meniscus replacement is currently possible by means of meniscal allograft transplantation (MAT) which provides replacement of the whole meniscus with or without bone plugs/slots. Partial replacement has been achieved by means of meniscal scaffolds (mainly collagen or polyurethane-based). Despite the favourable clinical outcomes, it is still debatable whether MAT is capable of preventing progression to osteoarthritis. Moreover, current scaffolds have shown some fundamental limitations, such as the fact that the newly formed tissue may be different from the native fibrocartilage of the meniscus.Regenerative tissue engineering strategies have been used in an attempt to provide a new generation of meniscal implants, either for partial or total replacement. The goal is to provide biomaterials (acellular or cell-seeded constructs) which provide the biomechanical properties but also the biological features to replace the loss of native tissue. Moreover, these approaches include possibilities for patient-specific implants of correct size and shape, as well as advanced strategies combining cells, bioactive agents, hydrogels or gene therapy.Herein, the clinical evidence and tips concerning MAT, currently available meniscus scaffolds and future perspectives are discussed. Cite this article: EFORT Open Rev 2019;4 DOI: 10.1302/2058-5241.4.180103.

Meniscal transplantation: state of the art

Meniscal resection is the most common surgical procedure in orthopaedics. When a large meniscal loss becomes clinically relevant, meniscal allograft transplantation (MAT) is a feasible option. However, although this technique has evolved since the ‘80s, there are still several controversial issues related to MAT. Most importantly, its chondroprotective effect is still not completely proven. Its relatively high complication and reoperation rate is another reason for this procedure not yet being universally accepted. Despite its controversial chondroprotective effect, nevertheless, MAT has become a successful treatment for pain localised in a previously meniscectomised knee, in terms of pain relief and knee function. We conducted a careful review of the literature, highlighting the most relevant studies in various aspects of this procedure. Precise indications, how it behaves biomechanically, surgical techniques, return to sport and future perspectives are among the most relevant topics that have been included in this state-of-the-art review.

Arthroscopic combined medial and lateral meniscus transplantation after double-tunnel, double-bundle anterior cruciate ligament reconstruction in the same knee

Meniscus transplantation in combination with anterior cruciate ligament (ACL) reconstruction has been used in the treatment of patients with meniscus and ACL deficiency. However, there have been no reports of arthroscopic surgery and the outcome of both medial and lateral meniscus allograft transplantation after double-tunnel, double-bundle ACL reconstruction. Herein, we report the case of a young male who received arthroscopic lateral and medial meniscectomy and ACL tibialis allograft reconstruction performed with the double-tunnel and double-bundle technique approximately 8 months after a knee injury. Approximately 4 months postoperatively he began to experience pain and weakness in the operated knee and subsequently underwent arthroscopic lateral and medial meniscus allograft transplantation in the same procedure. Second-look arthroscopy and magnetic resonance imaging revealed the meniscal allografts to have normal shape and the ACL grafts to be relatively intact at 18 and 30 months after surgery. His knee appeared stable and the range of motion was normal. Our hypothesis was that knee stability could reliably be restored with this combined procedure and the meniscal grafts and ACL graft could provide protection for each other. We suggest that medial and lateral meniscus allografts for one patient should be from the same donor. In the operation, attention must be paid to the direction of the bone tunnels used to fix the horns of the meniscal grafts to avoid communication with other tunnels in the tibial plateau.

Outcome after partial medial meniscus substitution with the collagen meniscal implant at a minimum of 10 years' follow-up

PURPOSE

The aim of the study was to evaluate the clinical outcome of a collagen meniscus graft implanted in an injured medial meniscus after a minimum of 10 years' follow-up.

METHODS

Twenty-five patients underwent arthroscopic implantation of the collagen meniscus device. They had either persistent compartmental joint line pain due to a previous medial meniscus resection (5 cases) or a large irreparable meniscus tear at arthroscopy (20 cases). Implant failure was defined as infection due to the implant or mechanical failure of the device. Twenty-two patients returned for clinical, functional, and radiographic evaluation. Magnetic resonance imaging was also performed and was analyzed with the criteria of Genovese et al. (where type 3 indicates normal and type 1 indicates completely abnormal). All the aforementioned evaluations were carried out at a minimum of 10 years (range, 10.1 to 12.5 years) after the procedure.

RESULTS

The mean Lysholm score improved from 59.9 preoperatively to 89.6 at 1 year (P < .001), and it was 87.5 at final follow-up (P < .001). The results were good or excellent in 83% of the population. No differences were observed when we compared the Lysholm score at 1 year of follow-up with the score at final follow-up (P > .05). The mean pain score on a visual analog scale improved by 3.5 points at final follow-up. Patient satisfaction with the procedure was 3.4 of 4 points. Radiographic evaluation showed either minimal or no narrowing of the joint line. Magnetic resonance imaging showed type 2 in 64% of cases and type 3 in 21%. All cases showed less volume than expected (size type 2 in 89%). The failure rate in the patient population was 8% (2 of 25). There were no complications related to the device.

CONCLUSIONS

Although there were several different types of patients and acute and chronic tears were treated in a limited number of patients, meniscal substitution with the collagen meniscal implant provides significant pain relief and functional improvement after a minimum of 10 years' follow-up. The implant generally diminished in size, but the procedure proved to be safe and had a low rate of implant failure on a long-term basis. No development or progression of degenerative knee joint disease was observed in most cases.

LEVEL OF EVIDENCE

Level IV, therapeutic case series.