Dr. De la Varga, a specialist in Traumatology, explains below what a meniscus tear is, what are the possible treatments that can be used depending on the type of tear and the patient’s condition, and what are the stages of recovery.
What are menisci?
The menisci are fibrocartilaginous, semi-soft structures that are located between the femur and the tibia, and their function is to improve the fit between the two bones, favoring joint stability and cushioning the load supported by the cartilage.
There are two menisci in each knee, one in its internal face and another in the external face. Its crescent shape and wedge-like profile favor the perfect fit between the curved femoral condyle and the flat tibial plateau, thus allowing a more uniform distribution of the transmission of weight from the femur to the tibia.
Three zones are differentiated in the meniscus according to the blood supply they receive:
– The vascular zone (red zone), 3 to 5 mm thick, is the outermost, close to the joint capsule, and is the one that receives blood supply and has nerve endings. The breaks in this zone are very painful, but they are the ones that better respond to the meniscal suture.
– The intermediate zone, 3 to 4 mm thick, receives little blood supply. It has little chance of healing if sutured, however, if its regeneration is stimulated with biological therapies, healing rates similar to those of the red zone are achieved.
– The avascular zone (white zone) corresponds to the rest of the meniscus. The progressively thinning free edge lacks blood supply and nerve endings and is unable to heal. Ruptures in this area require resection.
Treatment of a meniscal tear
We are increasingly aware of the importance of preserving the meniscus, as we know its fundamental role in the stabilization of the knee and in the absorption of loads and impacts protecting the cartilage of the knee.
Types of treatments:
– Partial meniscectomy
It consists of the resection of the damaged part of the meniscus preserving as much of it as possible.
– Suture and meniscal repair
The success of meniscal repair depends on three factors: an adequate vascular supply in the area to be sutured, the overall stability of the knee and the age of the patient.
The worst prognostic factors for the healing of a meniscal suture are if the tear is complex, with great meniscal destructuring or if it appears in a knee with chronic rupture of the cruciate ligaments or with great muscular atrophy that originate an important instability of the knee. In young patients meniscal repair is always attempted.
In older patients with less demanding physical activity, limited meniscectomy is chosen. Although older patients have been found to improve as well as younger patients in selected tears, there is a higher complication rate and the long-term benefit of preserving the meniscus is less in these patients, as they will not be as likely to develop osteoarthritis.
Arthroscopic meniscal repair techniques are performed using biodegradable sutures and devices. The complication rate for meniscal repair is approximately 15%, being slightly higher for medial than for external meniscal repairs.
– Meniscal implants and grafts
These are artificial meniscal substitutes, either natural (collagen) or synthetic (polyurethane), which are used to fill the space left after removal of a portion of torn meniscus. Their purpose is to avoid, especially in young patients, the appearance of post-meniscectomy syndrome and early osteoarthritis. On this artificial meniscus, which is really an inert matrix, cells must grow to convert this artificial tissue into living tissue, so that it can be maintained over time.
In order to be used, certain conditions are required, such as that there must be healthy meniscus on both sides of the graft so that it can be sutured and remain stable.
– Meniscus transplants
They are performed with freeze-dried or frozen grafts of complete cadaveric menisci. Their use is similar to that of meniscal implants but in cases where most of the original meniscus has been removed. They are used to prevent the early onset of osteoarthritis of the knee, especially in young patients.
Recovery from meniscus surgery
Recovery from meniscal surgery, being a minimally invasive arthroscopic surgery, is very fast, although its duration depends on the surgical technique used:
– Partial meniscectomy: in the event that the meniscus is not recoverable and it is opted to remove the damaged portion of the meniscus, the recovery period is 3 weeks for a normal life and 6 weeks for the return to intense sports activity.
The patient is discharged a few hours after surgery. During the first 48h you will have to walk with crutches with partial support and apply measures for the reduction of inflammation. On the third day he will begin physical therapy aimed at recovering muscle tone and full mobility, which should be achieved by the end of the first week of physical therapy, at which time he will stop using the crutches.
During the second week you will start using the bicycle for muscle strengthening and for the third week you will continue with elliptical and fast walking to regain muscle tone.
– Meniscal suture: the process is similar to that described for partial meniscectomies. The difference is that the times are lengthened, since the meniscal suture must be defended until it heals. During the first three weeks, walking will be maintained with crutches without resting the foot on the ground and knee flexion will be limited to 90º, avoiding maximum flexion. Muscle strengthening and non-loading proprioception exercises will be performed during these weeks. Weekly ultrasound-guided infiltrations of growth factors will be performed in the sutured meniscus to increase the chances of healing.
From the third week onwards, partial loading will be started for a few more days and the crutches will be discontinued after 6 weeks, by which time full joint mobility should have been regained. Return to sporting activity and competition will occur 3 months after meniscal suturing.