I decided today to share with the community a small article that continues my acquaintance with orthopedics and bio-mechanics. The topic of discussion is Meniscus of the knee joint. What is it, why are they needed, why are they so important and what are the current trends in the treatment of meniscus injuries.
The purpose of this article is to inform people.
Who cares – we go under the cat.
The Latin word meniscus comes from the Greek μηνίσκος (meniscus), which translates as “crescent” – if you look at the picture below, you can understand where the name came from (red arrow – inner meniscus, green – outer).
Initially, Meniscus in the knee joint were described by Sutton in 1897 as rudimentary structures. Gradually, with an increase in understanding in medicine and research, the opinion about the “vestigial” of Meniscus has changed a lot, and now they are considered as an important structure of the knee joint. Meniscus are cartilaginous structures of a lunar shape, triangular in cross section, peculiar “laying” between the articular surfaces of the femur and tibia.
The knee joint is complex in its bio-mechanics, flexion / extension, external and internal rotation are possible in it. The articular surfaces are not completely congruent to each other (that is, the articular surface of the femur does not repeat 1 in 1 articular surface of the tibia).
Meniscus are needed to:
- stabilize the joint, especially in rotational movements (Shoemaker and Markolf 1986)
- increase the area of contact of the articular surfaces of the femur and tibia, distributing the resulting load evenly over
- he entire surface of the joint (Arnoczky et al 1987)
- participate in the absorption of shock by the Meniscus (Fithian et al 1990)
- participate in joint lubrication and nutrition (Renstrom and Johnson 1990), proprioception (Karahan et al 2010)
Since the Meniscus are mobile (the outer one is more mobile than the inner one) and are displaced during flexion and extension in the joint, then p. 2 works at different positions of the joint (black arrows – load distribution).
In order to understand a little better in numbers – removal of the external meniscus leads to a decrease in the contact area of articular surfaces by 40-50% and to an increase in the load in the contact zone of “cartilage-cartilage” by 200-300% of what is considered normal (Bedi et al 2012, Henning et al 1987).
Meniscus damage is most likely to occur in young people (and men are 4 times more likely than women) aged 21-30 years (Drosos and Pozo, 2004) – at least when we talk about traumatic ruptures. In addition to traumatic, there are so-called “Degenerative” ruptures, that is, chronic damage to the Meniscus due to local inadequate loads on this area of the joint or due to changes in the structure of the meniscus with increasing age of a person.
Given that meniscus damage is common enough, you need to understand how they are treated.
Load a long digression into the anatomy, classification of damage, etc. I won’t. Globally, there are complete breaks (when the break line goes to the articular surface) and incomplete (the break line does not go to the joint surface). Very often, according to the classification of MRI lesions according to Stoller, complete breaks are IIIa-IIIb, incomplete – I-II degree. A joint can hurt with all types of ruptures, but incomplete rarely require surgical intervention. Complete tears due to the instability of the meniscus and the maintenance of inflammation in the joint can lead to adverse effects and give constant pain.
Conservative (non-surgical) treatment most often includes stabilization of the joint in specialized orthoses (fixatives), which limit certain movements in the joint, anti-inflammatory therapy, and exercise therapy in the non-acute period. Injections into the joint with hyaluronic acid (outside the acute period of inflammation) can be used – while many studies are being carried out now, some of which cannot be said about the high effectiveness of these drugs. Also in recent years, the use of biological preparations (from adipose tissue enriched in plasma platelets, etc.) has been actively studied. It must be understood that in many respects the research data is contradictory. One of the last sufficiently high-quality studies, albeit with a small sample of patients, on the effectiveness of PRP in the surgical reconstruction of Meniscus – DOI: 10.1155 / 2018/9315815
Conservative therapy rarely lasts more than 4-6 weeks, and if it is ineffective, it is recommended to discuss surgical options with the doctor.
Meniscus surgery is currently performed minimally invasively – that is, several (2-3) small “punctures” of 1 cm length are made in the knee joint, a camera and instruments are inserted – this is called “arthroscopy”.
Even 5-10 years ago, a meniscus resection was widespread in our country – that is, the removal of the torn part, which in theory should eliminate instability in the joint. Sometimes the meniscus was completely removed (meniscectomy). Such operations had a great advantage – the patient activated early, quickly recovered and returned to an active life.
Nevertheless, trends in the world are changing. Now the meniscus suture is considered the “gold standard” – with the help of tools, the torn part of the meniscus is sutured (or sutured to the joint capsule), thereby preserving the meniscus, and if it is a favorable type of rupture, it also grows together. After such operations, a long rehabilitation is required (with limited load, and sometimes movements in the joint for 4-6 weeks).
At first glance, the option of removing the torn part of the meniscus looks more interesting (faster human recovery, no specific rehabilitation is required) – but in some European countries, meniscus resection has been removed from interventions paid for by “default” insurance. That is, the surgeon needs to very strongly substantiate why in this case he did not sew the meniscus (data personally from one orthopedic professor from the UK regarding the actual state of the problem in the UK).
Are Europeans stupid? Not.
Faucett sc et al
“Meniscus Root Repair vs Meniscectomy or Nonoperative Management to Prevent Knee Osteoarthritis After Medial Meniscus Root Tears: Clinical and Economic Effectiveness.”
Am J Sports Med. 2019 Mar; 47 (3): 762-769. doi: 10.1177 / 0363546518755754. Epub 2018 Mar 8.
It is reliably shown that the development of osteoarthritis (arthrosis “as before”) is two times lower in a 10-year perspective in the group where meniscus was stitched, compared with groups where the meniscus was resected (partially or completely removed) or not touched and left the patient walk with a break.
That is, with the technical feasibility and the desire of the patient, ceteris paribus, it’s right to stitch the meniscus for the life of the joint. Unfortunately, in our country not all meniscuses are sewn (we sew, and I am proud of the separation).
Under the spoiler I’ll hide a link to youtube with an animation of the meniscus suture.
There are two more options for the surgical treatment of Meniscus, on which there is no point in dwelling in detail – this is transplantation of a donor meniscus and hemming of an artificial meniscus. The first option in Russia is not considered due to the state of transplantology. The second option is theoretically possible, but extremely expensive.
Thanks for attention!
How are meniscus problems diagnosed? Who makes the diagnosis?
Diagnostics goes along the path of “an orthopedic traumatologist – examination, clinical tests, medical history, etc. – if there is a suspicion of damage to the meniscus (and there are pains in the knee joint for various reasons), an MRI is really, moreover, preferably of good quality – a tomography resolution of 1.5 Tesla. And take the disc, because all the operating surgeons I know (including myself) always look at all sections – the solution to the issue of conservative treatment or recommendations for surgery. In case of doubt (and the ineffectiveness of conservative therapy), diagnostic arthroscopy (examination of the joint by the camera from the inside) can really be recommended, which easily goes directly to the treatment right.
the accuracy of the diagnosis is
Once, a long time ago, my MRI friend saw a rupture of the anterior cruciate ligament, there was no clinical instability, hesitated, the patient redid the MRI on a better tomography scanner – indeed a ligament rupture. Since there was still a meniscus rupture, we went for arthroscopy. As a result, the meniscus was stitched, and the bunch was intact.
In the article, I did not see a clear explanation of why go to surgery?
First, the patient goes to the doctor when something hurts him. In this case, the knee joint. Without pain, there will be no diagnosis, and we will not know if everything is fine with the meniscus.
Secondly, the torn meniscus cartilage itself doesn’t particularly “wear out”. Just not performing a stabilizing function, the load on the articular cartilage becomes local and very high – from there damage to the cartilage, chronic inflammation and the development of osteoarthritis.
Well, and so – above I wrote the meniscus functions, which to one degree or another are lost at break. Of course, the joint will be bad from this)
At the expense of injections, it is also not quite clearly described.
Hyaluronic acid injections are indeed sometimes in question now. I can’t completely exclude and brand them ineffective, especially since there are studies that talk about the anti-inflammatory effect of these drugs. There is also about cartilage nutrition and inhibition of osteoarthritis. They are not the main treatment method, they are contraindicated in case of active inflammation (synovitis), in other cases they can be considered by a doctor.
PRP is another matter. This is platelet-rich plasma – blood is taken from the patient, centrifuged, plasma with a high platelet content is isolated (due to the “preparation” technique) and injected into the joint (not only joints but also ligaments are treated this way). At the injection site, platelets disintegrate, immediately releasing many anti-inflammatory factors and regeneration factors. Pros – complete safety, more and more studies show effectiveness in certain conditions, cons – can be painful. And expensive.
Other options for biological therapies do not yet have a lot of evidence and, in my opinion, can only be used in situations of “either try or operate”.
I do not consider chondroprotectors in any cases. The evidence base of these drugs is too low.
need to undergo rehabilitation
In meniscus surgery, according to our observations, patients can do simple exercises from rehabilitation protocols themselves. Rehabilitation after reconstruction of the anterior cruciate ligament is another matter.
Most often it does not make sense to look for a center – you need to look for a specialist, physiotherapist and sports medicine doctor or rehabilitologist.
then all the same, all your life you need to take care of the knee and give a metered, but regular load.
In general, as with any problem in the musculoskeletal system - to know about it and prevent exacerbations. knee surgery is not a sentence