Introduction to Meniscus Transplantation
Meniscus transplantation (or donor meniscus graft) (Fig. 1) represents the most valid therapeutic option to attempt to slow down the progression of osteoarthritis without resorting to a metal prosthesis in patients who have undergone subtotal or total meniscectomy.
The menisci used for this procedure are harvested from deceased donors and are preserved in specialized musculoskeletal tissue banks.
The Importance of the Meniscus in the Knee Joint
Meniscus transplantation is a crucial procedure for those suffering from severe meniscal injuries. The meniscus, a fundamental component of the knee, contributes to shock absorption, joint stability, and even load distribution.
When damaged, the meniscus can cause pain, limited range of motion, and, in the long term, osteoarthritis.
This topic is explored in the following sections:
Anatomy and Function of the Meniscus
Among the two menisci, the medial meniscus is less mobile, which provides stability to the joint. The lateral meniscus, on the other hand, is more mobile as it is more involved in knee flexion and extension movements.
At birth, the meniscus is fully vascularized, but this vascularized portion—known as the “red zone”—gradually reduces over time, remaining limited to the outermost edge of both menisci.
Over the years, there is a progressive reduction in the capillary network and an expansion of the “white zone” (which is poorly vascularized).
The neural network has a similar distribution and is mainly responsible for collecting sensory information about joint position and sending it to the brain.
Structure of the Meniscus
The knee contains two menisci: the medial and the lateral meniscus. These crescent-shaped cartilage pads act as shock absorbers between the femur and tibia.
The meniscus is an important fibrocartilaginous structure in the knee joint. Each knee has a medial and a lateral meniscus, both located between the femur and tibia.
These structures help distribute body weight more evenly, thereby reducing stress on the cartilage covering the joint surfaces. Menisci also assist ligaments in stabilizing the knee.
Traumatic meniscal injuries are relatively common, particularly in young and active individuals, and are caused by acute trauma. These injuries must be distinguished from degenerative lesions, which occur without trauma and are more common after the fourth decade of life. Removing more than 50% of a meniscus (meniscectomy) significantly alters joint structure and may lead to knee osteoarthritis. [1]
Functional Roles of the Meniscus in the Knee
Beyond cushioning, the menisci aid in the proper distribution of compressive forces through the knee joint and contribute to its lubrication and nutrition. Their main function is to absorb shocks and facilitate rolling and gliding movements of the joint, allowing smooth interaction between the femoral condyle and tibial plateau.
Indications for Meniscus Transplantation
Musculoskeletal tissue transplants do not require immunosuppressive therapy, and the risk of infection is extremely low—comparable to that of a blood transfusion. Once a meniscus of suitable size is found, it is transplanted by suturing it to surrounding soft tissues and anchoring it to the bone.
Conditions and Injuries Requiring a Transplant
Meniscus transplantation is indicated in cases of irreparable subtotal or total meniscal injuries that cause significant pain and functional limitation, unresponsive to conservative treatments.
Benefits for Knee Health
The transplant aims to reduce pain, improve mobility, and prevent the early onset of post-traumatic osteoarthritis, significantly improving the patient’s quality of life.
Biological Meniscal Implants: Innovations and Benefits
Biological meniscal implants offer an excellent therapeutic option for symptomatic partial meniscal loss, aiming to restore the function of the natural meniscus using biocompatible materials that minimize rejection and promote integration with the joint (Fig. 2).
These devices have different indications than meniscus transplants: they are suitable only for irreparable partial lesions that cause significant pain and functional limitation unresponsive to conservative therapy.
Arthroscopic Meniscus Transplantation
Meniscus transplantation can be performed arthroscopically—a minimally invasive surgical technique that reduces recovery time and associated risks.
To minimize surgical trauma, we developed an “all-inside” mini-invasive technique that allows the entire procedure to be performed arthroscopically, without opening the knee.
Ours is currently one of the largest case series in the world for this type of procedure, which we have been successfully performing for over 10 years. [2-4]
Preparing for Meniscus Transplantation
Pre-operative Assessment
A thorough pre-operative evaluation is essential to determine transplant eligibility, including advanced imaging and functional knee assessments.
Post-Transplant Recovery and Rehabilitation: Long-Term Outcomes and Expectations
Rehabilitation plays a key role in the success of a meniscus transplant, with a personalized program focused on restoring knee strength and mobility.
Results are favorable—even long-term—in professional athletes. [3, 8] After surgery, the patient begins a rehabilitation program that, if properly followed, will allow resumption of normal daily activities after about 45 days.
Return to sports is typically allowed around 3–4 months post-op. The same timeline applies to biological meniscal implants. Patients undergoing meniscus transplantation can expect a significant improvement in function and quality of life. Ongoing research and innovations in biological meniscal implants promise even better outcomes in the future.
Meniscus Transplantation and Biological Meniscal Implants via Arthroscopy: Prof. Marcheggiani Muccioli's Experience
Prof. Giulio Maria Marcheggiani Muccioli has distinguished himself in the field of orthopedics, beginning with a cum laude degree in Medicine and Surgery from the University of Bologna in 2006, followed by a cum laude specialization in Orthopedics and Traumatology at the Rizzoli Orthopedic Institute and a PhD in Surgical Sciences.
His career includes the academic role of Associate Professor of Orthopedics at the Faculty of Medicine and Surgery of the University of Bologna, where he has focused on biomechanics and pathology of the lower and upper limbs.
He expanded his expertise through international fellowships, including experiences in the UK, Japan, and the United States, establishing himself as an orthopedic surgeon with extensive practical experience, demonstrated by over 250 surgeries per year.
Prof. Marcheggiani Muccioli also plays a key role in training the next generation of physicians through university teaching across multiple medical and surgical disciplines.
He is one of only 10 Italian surgeons selected in the past 20 years by the American Knee Society to participate in the prestigious John Insall Fellowship in Knee Prosthetic Surgery. His prolific contribution to the field is reflected in over 250 scientific publications and a constant presence in academic and scientific conferences, demonstrating a deep commitment to innovation in the treatment of knee and shoulder pathologies, advancement of minimally invasive surgical techniques, and sports medicine.
bibliography
- Knee joint changes after meniscectomy. Fairbank TJ. J Bone Joint Surg Br. Nov 1948;30B(4):664-670.
- Meniscal Allograft Transplantation Without Bone Plugs: A 3-Year Minimum Follow-up Study. Marcacci M, Zaffagnini S, Marcheggiani Muccioli GM, et al. Am J Sports Med. 2012 Feb;40(2):395-403.
- Arthroscopic meniscus allograft transplantation in male professional soccer players: a 36-month follow-up study. Marcacci M, Marcheggiani Muccioli GM, Zaffagnini S, et al. Am J Sports Med. 2014 Feb;42(2):382-8.
- Survivorship and clinical outcomes of 147 consecutive isolated or combined arthroscopic bone plug free meniscal allograft transplantation. Zaffagnini S, Grassi A, Marcheggiani Muccioli GM, et al. Knee Surg Sports Traumatol Arthrosc. 2016 May;24(5):1432-9.
- Prospective long-term outcomes of the medial collagen meniscus implant versus partial medial meniscectomy: a minimum 10-year follow-up study. Zaffagnini S, Marcheggiani Muccioli GM, Lopomo N, et al. Am J Sports Med. May 2011;39(5):977-985.
- Arthroscopic collagen meniscus implantation for partial lateral meniscal defects: a 2-year minimum follow-up study. Zaffagnini S, Marcheggiani Muccioli GM, et al. Am J Sports Med. 2012 Oct;40(10):2281-8.
- Two-Year Clinical Results of Lateral Collagen Meniscus Implant: A Multicenter Study. Zaffagnini S, Grassi A, Marcheggiani Muccioli GM, et al. Arthroscopy. 2015 Jul;31(7):1269-78.
- A professional athlete functionally active 10 years after an arthroscopic lateral collagen meniscus implant. Marcheggiani Muccioli GM, Lullini G, Cammisa E, Leardini A, Zaffagnini S. Knee Surg Sports Traumatol Arthrosc. 2020 Feb 3. doi: 10.1007/s00167-020-05876-y.
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