Meniscus reconstruction is an exciting new keyhole procedure in which a meniscal implant (an artificial piece of meniscus) is stitched into the knee to replace lost meniscus tissue from previous cartilage removal surgery (partial meniscectomy). The meniscal implant acts as a scaffold to allow the in growth of new meniscus like tissue.
What are the benefits of meniscus scaffold reconstruction?
1. The aim of the surgery is to help reduce knee pain and restore knee function in individuals who have on-going knee pain following previous meniscus surgery. Meniscus scaffold reconstruction has been shown in clinical studies to provide good pain relief in the early years following surgery. [Link ref to Warwick paper]
2. In addition to this it is hoped that the procedure may reduce the risk of arthritis and the need for further operations. This is because the meniscus is the main shock absorber or cushion inside the knee and therefore by replacing the lost section of meniscus this may improve cushioning on the joint surface (chondro-protection) and in turn preventing further wear and tear (osteoarthritis).
There are currently two commercially available meniscal implants; one made from a synthetic plastic scaffold and one made from collagen from animal sources. I currently use the synthetic plastic version called the Actifit implant (Orteq sports medicine).
Who is meniscus scaffold reconstruction intended for?
Meniscus reconstruction is intended for younger people with on-going knee pain following previous partial meniscus removal surgery. It is however not suitable for everybody. Some of the points to consider include:
1. State of the remaining meniscus: In order to be able to stitch a piece of artificial meniscus into the knee there must be an intact edge (rim) of existing meniscus and there must be sufficient tissue at the front and back of the knee (anterior and posterior horns). It is not recommended to carry out meniscus reconstruction if there is insufficient tissue to stitch on to.
2. State of the knee joint surface: Meniscus reconstruction is not as successful if there is already significant underlying wear (osteoarthritis) within the knee joint. It is more suited to those with early or no wear.
3. Body mass index: increased bodyweight is a relative contraindication to surgery
4. Knee alignment and stability: A prerequisite for surgery is a stable, well-aligned knee. Therefore if the knee is unstable (such as in the case of an ACL tear) or if the body’s natural alignment means that its load is passing through the affected section of the knee then you may require a stabilising (such as ACL reconstruction) or realigning procedure (such as high tibial osteotomy or distal femoral osteotomy) in combination with meniscus scaffold reconstruction.
5. Rehabilitation: Patients undergoing this type of surgery require to be highly motivated and require to undergo a strict post-operative rehabilitation protocol.
What does the procedure involve?
This is a keyhole procedure carried out through a few small wounds at the front of the knee.
An arthroscopy (keyhole camera exploration) of the knee is carried out first to ensure suitability for the procedure. If the state of the remaining meniscus and joint surface is suitable for meniscus scaffold reconstruction then the procedure is carried out at the same time.
The patient’s remaining meniscus is prepared using keyhole instruments to accept the meniscus scaffold implant. This involves freshening up the rim of the meniscus and shaping it to fit the implant. The size of the defect to be filled is measured with a malleable ruler. This is usually around about 4.5 cm in length. The meniscal scaffold implant is then cut to size, it is passed inside the knee using keyhole instruments and then stitched into place using keyhole stitching techniques.
Following the procedure, the knee is protective in a knee brace for approximately 8 weeks.
What are the risks associated with meniscal scaffold reconstruction?
All surgical procedures carry some degree of risk. Generally the risk associated with keyhole surgery is very low. There is a small risk of infection associated with any operation; it is very low (<1%) with keyhole surgery. Care is taken to try to minimise the risk of infection. There is a small risk of stiffness with any knee surgery. Specifically with this procedure there is also a risk of tearing the meniscus scaffold at some point following surgery. It is important to understand that meniscus reconstruction with synthetic scaffolds is a relatively new procedure. This means that there is not a lot of information yet about how well it works, how safe it is and which patients will benefit from it. For this reason, The National Institute for Health and Clinical Excellence (NICE) has produced a patient guideline on the procedure entitled 'Using keyhole surgery to repair damaged knee cartilage with a biodegradable implant'. This document is written to help patients who may have been offered this surgery to understand the procedure and consent (agree) to the surgery. It can be viewed by clicking on the following link. NICE meniscal scaffold patient guidelines
What should I expect following meniscal reconstruction?
Meniscus reconstruction surgery is carried out as a keyhole procedure usually under a general anaesthetic. You may require one night’s stay in hospital following the surgery.
There will be some localised knee swelling following the surgery.
The knee is protected in a knee brace following surgery and therefore you will be required to walk with crutches.
Rehabilitation is deliberately slow in order to protect the internal suturing used to fix the meniscus scaffold in place, and allow it to heal without being put under excessive strain.
At approximately one week following your surgery the brace is changed to a hinged knee brace. This allows the knee to be ‘locked out’ in the brace in full extension (straight) when walking but unlocked and able to bend when sitting down or lying down.
As the weeks go by the amount that your knee can bend within the brace and the amount of weight you can put through your leg will increase.
The knee brace is required to be worn for at least eight weeks following surgery, at all times during the day and night other than when showering or having a bath.
Following this you will require to work hard with our physiotherapists on specific knee exercises.