The menisci are small C-shaped pieces of cartilage that act like shock absorbers for the knee joint. They are situated on top of the shin bone where it meets the bottom of the thigh bone. The lateral or outside of the knee meniscus is much smaller that the medial.
With discoid meniscus the amount of meniscus and its shape are atypical. There are 3 broad classification of Discoid Meniscus:
A large percentage of people with this condition will remain completely asymptomatic throughout life or it will show up as an incidental finding on MRI when investigating something else.
The classic presentation is a popping or snapping that develops gradually without a traumatic origin alongside the following signs and symptoms:
For some, the discoid meniscus will become symptomatic without damage or a tear, for others the discoid meniscus will have a tear from a one-off event and present like any other meniscus injury. In some cases ,a twisting event of the knee causes acute pain, locking or giving way much like the way adults damage the meniscus.
There are a number of different presentations associated with this condition but the most common are:
This condition almost always affects the lateral meniscus (outside of the knee) and is estimated to affect up to 17% of the population. Discoid Meniscus affecting the medial meniscus (inside of the knee) is extremely rare – estimated at 0.1-0.3% of the population. Some authors have reported that on finding a Discoid Meniscus on leg scanned, the other leg has revealed an asymptomatic Discoid Meniscus in 79-97% of people. There is also thought to be a strong genetic component to this condition with parents who suffered similar symptoms as adolescents.
The incidence for males is higher than for females – 3.5 and 2.8 per 100,000 of population, respectively. The highest incidence of lateral discoid meniscus was in 15-18-year-old males at 18.8 per 100,000 of population. There is a greater incidence of discoid meniscus is Asian populations; Japan 13%, 10.6% in Korea and 5.8% in India, compared to Western populations – 3-5% in the United States.
At Pure, your Physio will take a detailed history of your symptoms followed by a thorough clinical examination to establish an informed hypothesis of the structures contributing to your pain and provide a working diagnosis. A fast and accurate diagnosis will mean that the most effective treatment and management plan can be implemented straight away, helping to achieve optimal outcomes. Your Physiotherapist will want to know how your condition is effecting you day to day so that your treatment can be tailored to your needs and will mean personalised goals can be established. Regular re-assessment will ascertain if your are making progress towards your goals and will allow adjustments to your treatment to be made.
Treatment of Discoid Meniscus varies depending on a combination of your signs and symptoms and how they are affecting you. At Pure Physiotherapy our expert clinicians will discuss your symptoms and help to guide you to the most appropriate care. As previously stated, a number of people will be completely asymptomatic and never know they have Discoid Meniscus, requiring no treatment.
Some groups may have snapping knee syndrome when the knee is bent, but it may not be painful and physical, sporting and recreational activity may not be impacted. At Pure, your Physiotherapist can work with you to create a program that maintains good muscular strength around the knee and exercises that emphasise joint control and co-ordination such as balance and plyometrics. Regular re-assessment will ensure you are making progress towards your treatment goals and will also provide the opportunity for adjusting your exercises to facilitate optimal recovery.
The prognosis for this condition is very good with a number of people developing symptoms without a tear being able to manage conservatively by strengthening the muscles and improving their control of the leg during activity. Ongoing support and advice will help you self-manage and reduce the likelihood of future complications.
A number of patients with Discoid Meniscus may have suffered a tear or it may continue to be symptomatic despite there being no tear and good strength. At this point imaging and the opinion from an Orthopaedic surgeon should be sought. Most surgeons favour a technique known as saucerization, where the discoid meniscus is surgically re-shaped to appear like a normal meniscus. If a tear is present within this normal structure, the surgeon will repair this or remove it as appropriate. Rarely the whole meniscus may need to be removed – if the tear is just too large. Finally, patients with the Wrisberg variant that is symptomatic, may need to have the back of the meniscus re-attached to the tibia, restoring what is considered, normal anatomy.
After any type of surgery and in conjunction with the surgeon, a progressive rehabilitation plan to restore range of movement, strength and control should be instituted and then progressed appropriately to suit the individual’s goals. Those who may require surgical intervention tend to do very well also, with low rates of complication and excellent results in the short, medium and long-term.
Kim, J. G., Han, S. W., & Lee, D. H. (2016). Diagnosis and treatment of discoid meniscus. Knee surgery & related research, 28(4), 255.
Sabbag, O.D., Hevesi, M., Sanders, T.L., Camp, C.L., Dahm, D.L., Levy, B.A., Stuart, M.J. and Krych, A.J. (2018). Incidence and treatment trends of symptomatic discoid lateral menisci: an 18-year population-based study. Orthopaedic journal of sports medicine, 6(9), 2325967118797886.