#treatment - Knee
- The meniscal cartilages are elastic shock absorbers inside the knee and damage to them increases the risk of future arthritis.
- Meniscal tears are very common surgical treatment is often performed using knee arthroscopy (keyhole surgery).
- The meniscal cartilages have a poor blood supply therefore most tears will not heal and simply require trimming.
- Some meniscal tears can be surgically repaired (success rate of about 90%).
Complete loss of a meniscus increases the contact pressures between the femur and the tibia by over 200%, causing increased wear and tear within the knee. This can lead to arthritis. The more tissue is lost, the bigger the risk. If a complete meniscus is removed, then the risk of developing arthritis over the following 20 years increases by about 15-fold.
Many meniscal tears are irreparable. However, in those that can potentially be repaired, there is a very strong argument for attempting a surgical meniscal repair.
With meniscal repair, tiny stitches are placed into the meniscal cartilage to close up and hold a tear. However, like any tissue, this does not guarantee that the tissue will actually heal up. If the meniscal tissue fails to heal then it is likely that eventually the tiny sutures will tear and fail, and the knee will remain symptomatic. However, the average success rate for meniscal repairs healing up successfully is approximately 90%, which is pretty good for any surgical procedure. If the repair does heal up successfully, then a patient should expect to make a full recovery with no major long-term consequences.
If a simple meniscectomy or partial meniscectomy is performed then the recovery after the surgery is normally quick. Patients are advised to rest their knees for the first 1 – 2 weeks and then to gradually and carefully get back to normal as quickly as they feel they can, with no specific restrictions in what they are allowed to do.
However, when a meniscal repair has been performed, it is vital that the tiny stitches are protected, as they can potentially snap if too much force is put on them. Also, when the knee is flexed, the meniscal cartilages are pinched at the back of the knee and this can cause a meniscal repair to tear and fail. Therefore, after meniscal repair, a patient’s knee needs to be protected to give the repair the best possible chance of healing up.
Different surgeons and different physiotherapists have got their own ideas and opinions regarding what kind of rehab is appropriate after meniscal repair, and there is a wide variation of opinion.
However, given that the meniscal repair sutures are so tiny and delicate and that the consequences of a re-tear are so serious, we advocate the following rehab regime:
the knee is kept in a hinged brace, locked at 0 – 60o flexion for 6 weeks (the brace can be removed intermittently to wash / dress etc, but when the brace is off the knee must be kept straight)
during this 6 week period, the patient is kept partial weight bearing (about 25% body weight) with 2 crutches
after 6 weeks, the knee brace and the crutches are discarded. The patient then needs to start a 6-week course of regular intensive physiotherapy rehab, aiming at restoring (in this order):-
knee range of motion (the knee will be stiff after having been in a brace for 6 weeks
muscle strength (the muscles will be weak and wasted)
proprioception (the reflexes to the muscles for balance and stability).
During the 6-week rehab period, the patient should avoid deep squats, running, hopping, skipping or jumping.
Only at the 3-month post-op mark, should the patient start gradually and carefully returning to running and gentle sport.
Unfortunately, MRI scans are not very good at seeing whether or not a meniscal repair has or hasn’t healed. This is because the resolution of a scan just isn’t good enough to differentiate between scar tissue within the cartilage vs. a tear that has failed to heal.
It would be possible to perform a repeat arthroscopy at the 3-month post-op mark, in order to visualise and probe the meniscal repair and check whether it has healed. However, with meniscal repair having a 90% success rate, this would mean that 9 out of 10 of the repeat arthroscopies would potentially have been unnecessary. This approach therefore really isn’t justified.
Therefore, the only practical way of finding out whether or not a meniscal repair has healed is to gentle test the knee out by slowly returning to normal activities and sports after the 3-month post-op mark. If the knee does well and there are no significant symptoms, then it follows that the tear must have healed up and the repair was successful. If, however, a patient is unlucky enough to develop recurrent symptoms and ongoing problems with the knee, then the assumption is that the attempted repair has failed. In this situation, if the knee symptoms are actually bad enough to warrant having something further done, then the only real option left is to have a repeat arthroscopy, go back into the knee and excise the damaged cartilage by performing a meniscectomy or partial meniscectomy.
It is essential that patients have a full understanding of what their surgeon might potentially find inside their knee, what potential surgical treatment options are available and what particular rehab might be needed.
It is extremely difficult for a surgeon to accurately predict with confidence what rehab any individual patient might need after knee arthroscopy, because this depends entirely on what is found and what is done inside the knee.
Some patients, such as self-employed labourers, might need to get back to work ASAP and may actually prefer to have a partial or even total meniscectomy rather than subject themselves to 6 weeks in a knee brace plus crutches after a meniscal repair. Other patients may simply ask their surgeon to go ahead and do whatever they think is best and most appropriate at the time of the surgery. My personal approach is to treat each patient’s knee as if it were either my own knee or the knee of one of my family, unless the patient has given me specific instructions pre-operatively to either do or not do something specific.
All of the above details emphasize just how crucial it is that you do spend proper time with your surgeon pre-op and that you do ask as many questions as you feel you need to.