A meniscus tear is one of the most common injuries for knees, and for good reason. It’s prone to degeneration, it’s a soft fleshy material and it doesn’t fully heal after each bit of damage.
But it’s not all doom and gloom! Getting diagnosed with a meniscus tear doesn’t automatically mean you need surgery, or that you’ll have long term issues.
Let’s start with the basics of the meniscus – what is it, why does it get injured and how does it recover.
What is a knee meniscus?
The design of the knee joint is essentially a rounded bit (the end of the Femur) sitting on a flat bit (top of the Tibia). It moves like a hinge, but that would cause the round bit to roll off the back of the flat bit. So we’ve got this slightly complex but cool mechanism that keeps the round end fairly centralised on the flat surface.
We’ve also got the challenge of shock absorbing. If the bones are too stiff on impact, it might damage them. If they’re too pliable, they won’t provide a rigid pivot for the leg muscles.
That’s all the job of the meniscus! It helps maintain a centralised force distribution as the knee bends (and doesn’t roll off the back of the joint), as well as providing some shock absorbing quality to the joint.
The shape of a meniscus is kind of like a wedge of lemon, with hooked ends that wrap around. It’s thickest on the outer rim, tapering down to a thin inside edge.
The outer rim has a small amount of blood supply and nerve endings, but the thinner inside edge has got almost no blood supply or nerves. That means that you don’t feel minor damage to the inside edge (WIN!) but it also doesn’t heal (no blood supply = no repair).
Why does a knee meniscus get injured?
Almost every adult has some meniscal tearing, often in the form of fraying and degeneration around the inside edge. It only becomes painful and produces swelling when one of those tears (or a fresh one) extends towards the middle and outer edges, where you have nerves and blood flow.
An acute meniscus tear is an injury that happens suddenly due to an incident – it causes sudden knee pain that can often feel pinpoint along with some swelling a few hours after the incident.
A degenerative meniscus tear is the end result of a gradual process, but it still causes the same symptoms. It just doesn’t have a sudden onset – the more common story is that it gradually became painful and swollen over several days after a big hike or day in the garden.
The most common cause of acute and degenerative meniscus tears is a compressive load with rotation. That might be landing heavily on one leg while twisting (like when you’re skiing) or compression from crouching down + twisting (like crouching/squatting down in the garden and rotating left and right).
Should I get knee surgery for my meniscus tear?
There has been plenty of research evidence in the last few decades to say that 95%+ cases won’t need an arthroscopy (aka. “keyhole surgery”) for a meniscus tear.
There are specific criteria that helps us identify patients who should consider surgery to trim or suture the tear:
- Locking of the knee – the knee literally gets stuck in a bent position and won’t “unlock” for a while. This usually indicates a flap-type tear that’s folding over and blocking the movement of the knee
- Complex tears on MRI – most tears go from the inside edge outwards, towards the rim, and these don’t need surgery in almost every case. But some nasty tears split from front to back (along the length of the meniscus), while others split and create an unstable section. These ones are more likely to require surgery but it’s still not a definite
- Lack of response to conservative (ie. non-surgical) rehab – if you’ve done everything right and the knee still hasn’t improved after a few months, it’s probably time to consider surgery
Each of these criteria are advisory and not an absolute – even if you have a complex tear, you’d still try non-surgical options for a few weeks to see if you can avoid surgery. The complex tear just means you’ll consider surgery as a viable option a little sooner than if you had a simple tear.
Physio rehab exercises for meniscal tears
The design of these exercises follows a set of guidelines, and you can design your own program as long as it fits the guidelines. It’s also worth noting that lifting heavy weights in the gym is fine for meniscal tears, PROVIDED YOU CAN CONTROL THE TECHNIQUE! Extra loading won’t bother a meniscus tear but tilting and twisting forces on the knee can delay your recovery.
Guidelines for Physio rehab exercises:
- No twisting forces – the meniscus is prone to overload with rotation pressure on the knee
- Avoid full flexion/bending of the knee – it compresses the back of the meniscus and usually aggravates the injury
- If it hurts, skip it for that week – try again next week
- If it’s swollen, don’t force the movement – the swelling acts like a hydraulic inside the knee joint and squeezing it only adds more pressure to the injury
Helpful exercises for meniscus rehab
- Box squats
- Leg press to half depth
- Hip bridges & hip thrusts
- Crab walks with band around knees
- Exercise bike
- Skipping (later in rehab)
Exercises to avoid with a knee meniscus injury
- Pallof press
- Single leg exercises (these are OK later in the rehab process)
- Step ups (OK later in rehab)
- Box jumps
- Cossack squats
Helpful tips during your rehab
Wearing supportive shoes will reduce twisting forces on the knee during the recovery phase, so they’re advisable for the first month or so.
Avoid activities with excessive rotation through the knee, such as walking on soft sand or agility sports like football in studded boots.
Anti-inflammatory meds can potentially cause more swelling in the first few days after a tear as they increase bleeding so they’re best avoided for at least 3-5 days post-injury.
Elevation of the leg to reduce swelling is ineffective as the fluid is contained inside the joint capsule, but compressive braces and bandaging can help increase the rate of absorption of fluid from the knee.
Meniscus tears don’t heal so you’ll be prone to further episodes if the knee is twisted while weight-bearing. You don’t need to avoid any exercises for life, just be cautious with ones that are prone to technique issues and produce compression + rotation.