New technology, techniques and research support efforts to ‘save the meniscus’

Recent research into innovative ways to treat the injured meniscus, such as meniscal replacement with synthetic implants made of polyurethane or collagen or special devices to suture the torn meniscus, has provided orthopaedic surgeons with increased options in the treatment of partial and complete meniscal tears. But, many surgeons in Europe continue to exercise caution when it comes to meniscectomy in their patients to prevent knee problems in the future.

“Take the risk of failure,” René Verdonk, MD, PhD, emeritus former chief of the orthopaedic and traumatology departments at Ghent University Hospital, in Ghent, Belgium, said. “The bigger the tear is, the more you should push the indication and take the risk of failure, because if you remove the meniscus, you are sure to have issues at a later date,” he told Orthopaedics Today Europe.

Even with the introduction of synthetic meniscus substitutes in Europe, such as the Actifit polyurethane scaffold (Orteq Ltd.; London, United Kingdom), many surgeons rarely forgo surgery for partial meniscal tears, according to Maurilio Marcacci, MD, of Istituto Ortopedico Rizzoli, in Bologna, Italy.

Once more treatment options became available, orthopaedists tended to take the approach of “careful neglect” in 10% to 15% of patients with meniscal tears, Johan Bellemans, MD, PhD, chief of the orthopaedics and traumatology department at UZ Leuven, in Pellenberg, Belgium, said.

Image: Christophe Vander Eecken

“This [rate has been lowered] to 0% because meniscal suturing has become easier with new devices,” Bellemans told Orthopaedics Today Europe.

Verdonk said sports medicine physicians at his institution implant the Actifit scaffold in patients with partial meniscectomy who have chronic pain, but stable or stabilized well-aligned knees. A 2013 study by De Coninck and colleagues and a 2012 study by P. Verdonk and colleagues, both published in the American Journal of Sports Medicine, showed excellent 2-year results with this implant.

Research into the polyurethane implant that Bellemans carried out revealed that patients who were best suited for the Actifit implant have a knee aligned within ±2° of normal with intact ACL, PCL and collateral ligaments.

According to Marcacci, the Actifit device has stable properties with more resistance and an easy surgical technique.

Downsides of an implant

Discussing why meniscal substitutes are not optimal for all patients, Bellemans noted the Actifit product may have a tendency to fail in some patients who undergo lateral implantation or in elderly patients and it may cause some symptoms, including residual pain, to persist.

“There still seems to be a gap between how these patients perceive their knees versus standard scoring scales,” Bellemans said. “Although these devices seem to work well in follow-up reports, they are not yet ideal.”

There are a few other options for meniscal replacement on the horizon, according to sources who spoke with Orthopaedics Today Europe.

Verdonk said researchers at London’s Royal Imperial College have experimented with silicone meniscus implants, although it is too early for any definitive results.

Collagen meniscus substitutes

Verdonk, who is an Orthopaedics Today Europe Editorial Board member, suggested using meniscal implants made of collagen for the same indication as the Actifit: a chronically painful partial meniscectomy in a stable, well-aligned knee.

Zaffagnini and colleagues found excellent clinical results at 10-year follow-up in patients who received the Collagen Meniscus Implant or CMI (Ivy Sports Medicine GmbH; Gräfelfing, Germany) after partial medial meniscectomy compared to controls.

“The clinical results are satisfactory and better than if you do a meniscectomy,” Verdonk said.

An advantage of the Actifit and CMI devices is both are resorbable, however, the Actifit has a very slow process of resorption, about 5 years, and therefore can be well followed up in situ, he said.

The CMI product, which is CE marked, has been used long term in Europe. In 2012, the U.K. National Institute for Health and Clinical Excellence issued full guidance to the National Health Service in England, Wales, Scotland and Northern Ireland on partial replacement of the meniscus of the knee using a biodegradable scaffold, such as the CMI or Actifit implants.

Meniscal allograft transplantation

Meniscal allograft treatment is only indicated in patients with painful total medial or lateral meniscectomy when they have well aligned, stable knees and limited cartilage degeneration. These patients are incapacitated at work and unable to perform their jobs or participate in athletics of any kind.

Furthermore, it is indicated in cases of arthritic disease, chondromalacia, chondral lesions, medial side pain or lateral meniscus removal, Marcacci said.

“Allograft is better from a mechanical aspect,” he told Orthopaedics Today Europe.

Verdonk and Romain Seil, MD, PhD, of Centre Hospitalier in Luxembourg, said they use fresh frozen, nonirradiated allograft because irradiation changes the mechanical quality of the collagen present in allograft tissue. Bellemans and others obtain their meniscal allograft from a tissue bank that uses a sterile harvest process and cryopreservation.

About 20 years ago, some investigators switched from meniscal allografts with bone plugs to ones without bone plugs, according to Verdonk and Bellemans. Surgeons once contended that bone plugs preserved hoop stresses and improved the graft fixation; however, recent findings show some ingrowth, extrusion, loosening or dislocation of bone plugs. Therefore, Verdonk and Bellemans have since switched to soft tissue meniscal allograft anchoring and using smaller tunnels of 2 mm to 3 mm each.

“We have been doing allograft transplantation techniques endoscopically for 15 years and we have seen no decrease in our results,” Bellemans added.

Allograft without bone plugs

Meniscal allograft surgery is quicker and easier when no bone plugs are used, Bellemans said. His team performs allograft implantations in less than 1 hour for most menisci and 75 minutes for the lateral meniscus.

The lack of bone plugs allows for better customization of meniscal allograft size, according to Seil. “In the keyhole or bone bridge technique, where you have a bridge of bone going from the anterior horn to the posterior horn insertion, you drill a horizontal tunnel through the tibial plateau and bring the bone [plug] bridge into the tunnel or keyhole,” he told Orthopaedics Today Europe.

Sizing is critical. “You must have the same size allograft as the knee itself,” he said.

Marcacci has encountered problems sizing meniscal allografts so they completely cover the posterior horn of the meniscus. He now takes steps to ensure good fixation of the anterior end of the allograft tissue to the meniscal tibial ligament and posterior horn.

“I followed these patients and I have seen good results and the number of recurrences of meniscal lesions in these patients is lower now,” he told Orthopaedics Today Europe.

Hope for meniscal regeneration

Research into ways to regenerate, rather than repair or replace the meniscus, is ongoing. Progress is being made with stem cells used in animal menisci but, according to Verdonk, it has not yet been experimented with in humans.

Marcacci and colleagues, however, have experimented with stem cell meniscal regeneration in sheep and obtained positive results.

“We did stop at human tests because there are a lot of stigmas surrounding stem cells,” he said.

According to Seil, it is too early to make any assessments of outcomes with stem cell meniscal tissue regeneration.

Bellemans has used platelet-rich plasma and bone marrow aspirate derived from the intramedullary canal, purified and injected into a scaffold to promote meniscal tissue regrowth. Research continues into ways to improve cell lines with these scaffolds, he said.

Patient age and meniscal lesion care

Verdonk, Bellemans, Seil and Marcacci agreed that if a patient is young and active, meniscal repair is a must, mainly because these patients have a better healing capacity. They noted that patients older than 50 years who have good knee biology without degenerative disease may still be good candidates for meniscal repair.

Bellemans frequently treats older patients with well-aligned knees with the CMI device.

“Age is not a primary determinant to do or avoid meniscal repair,” Seil told Orthopaedics Today Europe. “It is more [about] biology, healing and the type of meniscal lesion.”

Knee surgeon Philippe Beaufils, MD, of Centre Hospitalier de Versailles, in Le Chesnay, France, said he expands the indications for meniscal repair in children and adolescents to preserve their menisci for a longer life span. Contrary to what some believe, he said, children’s meniscal lesions need to be repaired.

“It has been said in the past that meniscus injuries in children are able to spontaneously heal, but it is not true,” Beaufils told Orthopaedics Today Europe. “The evolution of meniscus tears in children is the same as in adults. There is a risk of the meniscal tears [worsening] and to avoid this we propose to fix the meniscal injury and we push the indications of meniscus repair... not only for peripheral lesions, which are the main indication for meniscal repair, but even more for lesions that are not in the vascularized area of the meniscus.”

Indications for pediatric meniscal repair

There are three indications for meniscal preservation in children: congenital abnormalities, traumatic lesions and overuse syndrome, according to Beaufils. He repairs congenital abnormalities, such as a discoid meniscus, with meniscoplasty to reduce the meniscus. If the meniscus is unstable, Beaufils performs meniscus remnant repair.

Another congenital abnormality — the hypermobile meniscus or locking knee — may present in patients aged 12 years to 14 years. It requires posterior fixation of the lateral meniscus and if there is an ACL tear along with a traumatic lesion, Beaufils considers ACL reconstruction with a meniscal repair.

“Meniscectomy in children is very pejorative in terms of prognosis and secondary arthritis,” he said. “We have patients who are now 20, 25 or 30 years old who had previous lateral meniscectomy or medial meniscectomy at 13 or 14 years old and they have a huge amount of arthritis. We do not know how to treat these patients. Meniscus preservation in children is important and the reason why we push the indications.”

Conservative meniscal approaches

Regarding meniscal suturing, Bellemans cautioned against using it due to studies that showed complications. In a study in the process of being published, he and colleagues found a 10% failure rate with meniscal suturing and iatrogenic damage from suture failure. This resulted from “inadvertent deployment of the anchor or slippage of the anchor through the meniscal tissue,” Bellemans said.

“There is solid ground for further improvement of these devices and this confirms the fact that meniscal suturing is not that harmless or innocent,” he said. “It is better to do a conservative partial resection for radial tears than to try and do sutures and see the patient 2 years later with a retear.”

Radial tears present a real challenge because they are in the white-on-white zone that is not vascularized and cannot heal or be sutured, according to Verdonk.

“The radial tear goes up to the meniscal wall,” Verdonk said. “We would repair the meniscus on the outside and trim away the thin part of the meniscus because this does not heal.”

Surgeons interviewed mostly perform meniscal surgery arthroscopically rather than open. Seil noted that some horizontal tears require an open approach. He said open surgery is performed in young athletes with overuse injuries to preserve their meniscus. It allows the surgeon to see “inside” the meniscus from the outer part of the knee, which is needed since horizontal lesions do not open into the joint space and thus cannot be viewed arthroscopically.

“You have to do a posterolateral or posteromedial open repair, clean the inside of the meniscus, keep the upper and lower layer and suture the meniscus back to the capsule,” Seil said.

Beaufils attempts open surgery in young patients who have overuse syndrome. “It is a horizontal cleavage into the meniscus tissue associated with a cyst,” he said. “An early repair (preferably done open) avoids a secondary extension of the tear and thus a secondary meniscectomy.”

Rehabilitation, return to sport

Meniscal tears longer than 3 cm to 5 cm require more careful rehabilitation. Verdonk said this may include bracing for 4 weeks to 6 weeks, delayed weight-bearing and avoidance of squatting during sports for 3 months to 6 months.

When patients at Bellemans’ institution undergo meniscal tear suturing, afterwards they are subjected to two “protective arms.” In the first arm, patients undergo 2 weeks of rehabilitation. In the second arm, they are allowed increasing loads on the cartilage and repaired meniscus. He does not permit patients who were recently sutured to perform squatting or pivoting for 3 months to 6 months.

“I am convinced of the theory that we need to give some time to the cartilage and meniscal remnants to become anabolically accepting and stronger,” Bellemans said.

Seil, however, does not differentiate between lateral and medial meniscus tears as a way to simplify or customize his rehabilitation protocol. In the first 6 postoperative weeks, he restricts knee flexion to less than 90° to avoid shear forces, but allows full weight-bearing at the outset except for meniscal root or radial tears.

“In these situations, if you allow full weight-bearing, then you have distracting forces on these repair types,” he said.

Beaufils immobilizes children in a brace for 4 weeks but allows full weight-bearing. Postoperatively, they can return to swimming or cycling at 6 weeks to 8 weeks, to running at 4 months and to pivot sports at 6 months.

Conservative care options

Today, meniscal suturing is simpler with the newly available devices, according to Bellemans and Verdonk.

“The number of partial meniscus tears where we do completely nothing has reduced to 0%,” Bellemans said. “The least we do is stimulate vascularization and induce a healing response by abrading the underlying synovium and the neighboring soft tissues by scratching, scraping and curetting to create vascular access channels.”

Some surgeons take a more conservative “wait and see” approach. Marcacci is more conservative. He only performs meniscal repair for bucket handle tears or in young patients with a lot of discomfort. Seil treats degenerative tears in older patients with corticosteroid injections and said the results are good. Beaufils also takes a conservative approach. He only operates on children who are symptomatic and will not operate, for example, on a child with a discoid meniscus who is asymptomatic.

“If there are symptoms, we are aggressive with the discoid meniscus because there is a risk of secondary tear of the abnormal meniscus that renders surgery more complex and difficult,” Beaufils said. – by Renee Blisard Buddle

• References:
• De Coninck T. Am J Sports Med. 2013. doi:10.1177/0363546512463344.
• Verdonk R. Am J Sports Med. 2012. doi:10.1177/0363546511433032.
• Zaffagnini S. Am J Sports Med. 2011. doi:10.1177/0363546510391179.

• For more information:
• Philippe Beaufils, MD, can be reached at 177 Rue de Versailles, 78150 Le Chesnay, France; email: pbeaufils@CH-versailles.fr.
• Johan Bellemans, MD, PhD, can be reached at Campus Pellenberg, Weligarveld 1, B-3212 Pellenberg, Belgium; email: secretariaat.bellemans@uzleuven.be.
• Maurilio Marcacci, MD, can be reached at the Orthopaedic and Traumatology Clinic II, Biomechanics Laboratory, Rizzoli Orthopaedic Institute, Via Pupilli 1, 40136 Bologna, Italy; email: m.marcacci@biomec.ior.it.
• Romain Seil, MD, PhD, can be reached at Centre Medical, 76 rue D’Eich, L-1460 Luxembourg; email: rseil@yahoo.com.
• René Verdonk, MD, PhD, can be reached at Jan Palfijn Ziekenhuis, Henri Dunant Iaan 5, 9000 Ghent, and Jozef Ziekenhuis, Izegem, Belgium; email: rene.verdonk@me.com.

Disclosures: Beaufils is a consultant to Smith & Nephew and Orteq. Marcacci is on the Ivy Sports Medicine clinical advisory board. Bellemans and Seil have no relevant financial disclosures. Verdonk is a consultant to Orteq.

Do you find better outcomes when meniscal allograft transplantation is done with or without bone blocks?

The answer is unknown

Since there is an overall lack of randomized clinical trials on meniscal transplantation, as well as on meniscal repair, the answer to this question is unknown. We do not know if meniscal transplants have a better outcome compared to other procedures, like meniscal repair or partial or total meniscal resection, let alone specific procedures (with or without bone blocks) for meniscal transplants.

What we know today is that meniscal surgery has no additional effect on exercise (with or without the addition of placebo surgery) in the middle-aged patient with a meniscal tear verified by MRI, with or without concomitant osteoarthritis. There is also a lack of studies of this procedure in the younger, more athletic population. The question being asked is important, but it cannot be answered until it has been subjected to high-quality randomized controlled trials, which are much needed in orthopaedics.

Ewa M. Roos, PT, PhD, is professor and head of the Research Unit for Musculoskeletal Function and Physiotherapy at the Institute of Sports Science and Clinical Biomechanics, in Odense, Denmark.
Disclosure: Roos is on the National Board for Preventive Medicine, receives royalties for lectures from Össur, the Finnish Orthopaedic Society, Studentlitteratur and Monksgaard and is the Associate Editor of Osteoarthritis and Cartilage.

Hard to choose between techniques

It is difficult for a single surgeon to make a comparison of the results of the two main techniques for meniscal transplantation. Biomechanical studies on cadavers have shown the superiority of bone fixation, even though a recent study demonstrated comparable results.

One of the keys for a correct implantation is the correct size of the graft. I believe the soft tissue technique has great adaptability. Usually, I fix the posterior horn and the body of the meniscus first with all-inside or in-out sutures, then the anterior horn either with a tunnel (lateral) or with an anchor (medial), plus a number of out-in sutures. If the size does not match perfectly, without bone blocks it is easier to find a position closer to the anatomic location without stretching all the sutures. With bone blocks, there is a need for a slightly oversized graft to preserve the sutures. On the lateral side, a straight bone block induces a lesion to the posterolateral fibers of the ACL. The reason for using the soft tissue technique is that the bone block technique is aggressive and small mistakes, which can frequently occur in a demanding surgery like this, may bring about huge cartilage lesions.

Vincenzo Condello, MD, is an orthopaedic surgeon at Sacro Cuore - Don Calabria Hospital, in Verona, Italy.
Disclosure: Condello has no relevant financial disclosures.