Knee Information

This section provides a wealth of information about the knee; conditions that can affect it, treatment options and detail on the operations along with rehabilitation afterwards.
These pages are provided for general information only — you should not undertake any part of a programme unless instructed by your consultant or physiotherapist.

If you have had or are about to undertake knee surgery in my care, I hope that you will find these information sheets useful. The area is forever expanding as new innovations and information becomes available.

There is also a section of patient stories where patients have written helpful information about their journey to recovery. If you have anything to add to the site about your own experiences, please contact Mr Spalding at his office.

  • Knee Information
  • Knee Conditions and Topics
  • How Does Weight Affect My Knees
  • Knee Osteoarthritis and Obesity
  • The Torn Meniscus (Cartilage)
  • A Partial Meniscectomy?
  • Symptoms of a meniscus tear?
  • What is a meniscus?
  • Who needs a meniscus repair?
  • Meniscal Repair Surgery
  • Coping with the Worn Knee
  • The Female Athlete - ACL injuries
  • Acute Knee Injury
  • Injury Diagnosis
  • Common Injuries
  • What can be done?
  • General information about the knee

Knee Information

This section provides a wealth of information about the knee; conditions that can affect it, treatment options and detail on the operations along with rehabilitation afterwards.
These pages are provided for general information only — you should not undertake any part of a programme unless instructed by your consultant or physiotherapist.

If you have had or are about to undertake knee surgery in my care, I hope that you will find these information sheets useful. The area is forever expanding as new innovations and information becomes available.

There is also a section of patient stories where patients have written helpful information about their journey to recovery. If you have anything to add to the site about your own experiences, please contact Mr Spalding at his office.

Knee Conditions and Topics

This section provides a wealth of information about the knee; conditions that can affect it, treatment options and detail on the operations along with rehabilitation afterwards.

These pages are provided for general information only — you should not undertake any part of a programme unless instructed by your consultant or physiotherapist.

If you have had or are about to undertake knee surgery in my care, I hope that you will find these information sheets useful. The area is forever expanding as new innovations and information becomes available.

There is also a section of patient stories where patients have written helpful information about their journey to recovery. If you have anything to add to the site about your own experiences, please contact Mr Spalding at his office.

How Does Weight Affect My Knees

We are a growing population, not just in number but also in size! In 2011 almost 25% of the English population was obese and these numbers continue to rise.

Most of us understand that being significantly overweight can cause all sorts of problems with health such as high blood pressure, heart disease and diabetes, but what is it doing to our joints?

As rates of obesity have gone up in the UK, so have rates of osteoarthritis of the knee.

What is osteoarthritis of the knee?

Osteoarthritis, sometimes called OA, degeneration or ‘wear and tear’ is the progressive loss of a joint’s articular cartilage, this causes the joint to become stiff and painful. Articular cartilage creates a smooth protective covering over the ends of our bones so that we can move our joints freely without friction. Articular cartilage is only a few millimeters thick, over the years it can become worn away and the joint can become painful, this is osteoarthritis.

How do I know if am overweight?

Body mass index (BMI) and waist circumference can be used to estimate if you are a healthy weight. You can work out your BMI by dividing your weight in Kg by your height in meters2. A waist circumference over 102cm for men or 88cm for women is considered obese.

Find a BMI calculator tool here:
What is a healthy BMI for an adult?
less than 18.5 Underweight
18.5 – 24.9 Ideal
25 – 29.9 Overweight
30 – 39.9 Obese
40 +  Very Obese
How does being overweight affect my knees? Research shows that if you are overweight or obese you are at three times greater risk of getting knee osteoarthritis than the rest of the population. Your risk of knee OA also goes up the heavier you are, by 35% for each 5 BMI units you gain. Simply put; gaining weight increases the chances that you will suffer with osteoarthritis of the knees leading to pain and stiffness of the joints. The good news.  Losing weight reduces your chances of developing knee OA

Knee Osteoarthritis and Obesity

But what if I already have knee OA?

If you already have problems with your knees there is clear evidence that losing weight reduces the symptoms of pain and immobility and can delay or prevent surgical intervention. These findings are regardless of the level of structural damage caused by OA, improvement in symptoms is found in patients who lose weight no matter what their x-rays say.

There are benefits to losing weight if you need a knee replacement too. Performing a total knee replacement operation on an obese patient is technically more challenging for the surgeon, the surgery takes longer to perform and there is a higher risk of complications like infection. Over time implants used in total knee replacement fail more quickly in obese patients.

What is the best way to lose weight?

Studies show the most effective means of losing weight is following a lifestyle that gives you a ‘continuous energy deficit’. This essentially means that the amount of energy you put into your body as food and drink should be less than the amount of energy you use in your daily activities. Effective, long-lasting weight loss is achieved through adjusting your lifestyle, rather than crash dieting. Finding the best strategy that works for YOU is important and getting support from your family and friends can make a big difference. There are many weight loss plans and methods out there to chose from; here are some suggestions for effective weight loss programs.

Weight Loss Guide    |    How to Lose Weight

Exercise is an obvious way to lose weight but knee pain can make weight-bearing activities difficult. Running, football or squash may not be possible due to pain. With all types of exercise, be guided by what you can do comfortably and stop if it hurts too much. Cycling and swimming are excellent exercise alternatives that put minimal strain on the knees, but still get your heart rate up and burn calories.

If you can move about comfortably there is evidence that combining weight loss through diet and regular long-term exercise is effective at improving arthritis pain and mobility, in addition to the normal care you receive from your GP. Either weight loss or exercise is better than standard care alone, but combining both gets even better results.

If you are overweight or obese aim for losing 5% of your total current weight over 20 weeks to give symptom relief. Losing 10% within 12 weeks has been shown to have even more significant clinical effects.

What if I wait until after my surgery to lose weight?

The evidence says this is not the general rule! One study showed that after knee replacement 21% of patients gained further weight whilst only 14% lost weight. Don’t put off until tomorrow, what you can do today!

Weight loss reduces symptoms, delays surgery and, if surgery does become necessary, improves the outcomes you will experience.

Written by Rachel Milner (Medical Student) for the knee team UHCW NHS Trust 

BibliographyBlagojevic, M. et al., 2010. Risk factors for onset of osteoarthritis of the knee in older adults: a systematic review and meta-analysis. Osteoarthritis and cartilage / OARS, Osteoarthritis Research Society, 18(1), pp.24–33.
Christensen, R. et al., 2007. Effect of weight reduction in obese patients diagnosed with knee osteoarthritis: a systematic review and meta-analysis. Annals of the Rheumatic Diseases, 66(4), pp.433–439.
Gudbergsen, H. et al., 2012. Weight loss is effective for symptomatic relief in obese subjects with knee osteoarthritis independently of joint damage severity assessed by high-field MRI and radiography. Osteoarthritis and cartilage / OARS, Osteoarthritis Research Society, 20(6), pp.495–502.
Jiang, L. et al., 2012. Body mass index and susceptibility to knee osteoarthritis: a systematic review and meta-analysis. Joint, bone, spine: revue du rhumatisme, 79(3), pp.291–297.
Messier, S.P. et al., 2004. Exercise and dietary weight loss in overweight and obese older adults with knee osteoarthritis: the Arthritis, Diet, and Activity Promotion Trial. Arthritis and rheumatism, 50(5), pp.1501–1510.
Salih, S. & Sutton, P., 2013. Obesity, knee osteoarthritis and knee arthroplasty: a review. BMC Sports Science, Medicine and Rehabilitation, 5, p.25.

The Torn Meniscus (Cartilage)


Who gets a meniscus tear?

Anyone who has a twisting injury to the knee – from sports injuries to simply squatting on the knee.

A Partial Meniscectomy?

Most tears are in the ‘white zone’ of the meniscus – an area of the meniscus that does not receive a good blood supply and is not likely to heal from a meniscal repair. In this case, a small portion of the meniscus is then trimmed away in a procedure known as a partial meniscectomy, leaving the rest of the meniscus to protect the articular surfaces in your knee joint.



Symptoms of a meniscus tear?

• Pain: Pain is the main symptom that is typically felt in the inner or outer parts of the knee as the torn fragment catches in the knee when twisting or turning.
• Swelling: Swelling can occur due to inflammation within the knee.
• Locking: Locking of the knee can occur when the piece of torn meniscus gets trapped in the knee. The knee can then bend but won’t go fully straight.

Before A Meniscal Repair

You should make sure you fully understand what the operation involves before you agree to have your meniscus repaired. You should ask your doctor about what will happen on the day of the operation and what will happen after the operation. As with any operation, there are risks and benefits (see below).

After A Meniscal Repair

After your operation, it is important you follow these guidelines in order to make sure that your repaired meniscus heals in the best possible way:

• Knee Brace: Knee is kept straight in brace and weight bearing is allowed on the straight knee. When sitting, the brace may be unlocked and moved to a 90 degree angle. Keep brace on at night until it is comfortable enough to sleep without it. The brace is used for 1 month.
• After 4 Weeks: Brace can be removed and full weight bearing is allowed. Any form of squatting or twisting must be avoided at least for the first 3 months. Cycling and swimming is allowed after 1 month.
• Sports: Rehabilitation back to sports such as running is allowed after 3 months. Sports involving twisting and pivoting should be delayed until 4 to 6 months after your meniscal repair. This time frame needs to be checked with your surgeon as it can vary between people.
• Physiotherapy: Physiotherapy is advised to help you through the rehabilitation process in order to build strength in your leg and get you back to doing your regular activities.

 It is essential that weight is kept off the bent knee early on in the rehabilitation process and that sports involving twisting and pivoting should be avoided for at least 3 months after a meniscal repair. This is because the sutures holding the meniscus together are very delicate at the early stages of healing, and any pressure applied to the sutures – such as from walking, running or twisting – can cause the sutures to break. If this occurs, another surgery is necessary to repair the meniscus again!

What is a meniscus?


The meniscus is a ‘C’ shaped structure that acts as a cushion to protect the smooth joint surfaces of the knee joint. Often known as the footballers cartilage it can be easily injured.

There are two of these structures – one on each side of the knee joint - and if removed at an operation following injury then there is less protection of the bearing surfaces such that the joint will wear out sooner.

Usually only a small part is removed and the risk of later problems is low. Symptoms will include pain and swelling of the knee after activity and limitation in tolerance of impact type sports. Symptoms may gradually get worse over the years as the joint slowly wears.

Risks and Complications

As with any surgery, there are potential side effects associated with the general anaesthetics which are used. These can include feeling sick after surgery, having a sore throat or having a headache. Rarely are people allergic to some of the anaesthetic agents.

Your doctor will discuss any health issues you may have such as diabetes, heart disease and respiratory diseases, and although these are common issues, they do not normally prevent surgery from occurring.

Risks associated with surgery include infection, blood clots in the leg, and damage to blood vessels or nerves within the leg. About 8 out of 10 meniscal repairs will heal well. It is therefore possible to follow rehabilitation guidelines properly and not participate in sports for at least 3 months after a meniscal repair, or you risk having the repair fail, leading to another surgery.

How does a meniscus tear?

The most common mechanism for a meniscus to tear is following a twisting of your knee while your foot is planted on the ground. Your inner (‘medial’) or outer (‘lateral) meniscus may tear depending on how you twist your knee

Who needs a meniscus repair?

Damage to the meniscus will result in one of the 3 following possible treatments depending on the location of the tear and the size of the tear.

zones of the meniscus1) Non - Surgical Treatment: If the tear is not causing symptoms, your knee can be treated with simple painkillers and physiotherapy. If the knee is not swelling up and not hurting anymore, no further treatment is necessary. If these treatments have been tried but do not seem to help with your knee problem, surgery may be required.

2) Surgical Treatment – Meniscal Repair: If the tear is fairly large and within the ‘red zone’ (see below picture), this means that it is likely to heal well with a meniscal repair.

3) Surgical Treatment – Partial Meniscectomy: If the tear is in the ‘white zone’ (see below picture), it is not suitable for repair as it is unlikely to heal very well, therefore it is best to cut out the affected portion in a procedure called a ‘partial meniscectomy’.

Meniscal Repair Surgery

Damage or tears at the outside of the meniscus in the ‘red zone’ are near to a blood supply, which means it is closer to a source of nutrients and as a result is more likely to heal better. It can then be repaired using special sutures by ‘keyhole’ surgery – surgery which uses cuts in the skin only about 1 cm in length. The below image is taken from a small camera inserted into the knee (in a procedure known as ‘arthroscopy’) which shows a meniscus before and after it has been repaired with sutures. Once the meniscus is stitched into place, it allows the body to do the rest of the healing.


Meniscal Repair: On the above left picture, the tear in the meniscus has allowed the meniscus (B) to become loose, which can result in it being caught between thigh bone (A) and the shin bone (C). After meniscal repair (above right-courtesy of SMITH AND NEPHEW), a suture is holding the meniscus in place, preventing it from getting caught between the thigh bone and the shin bone.

If the meniscal tear is far from a blood supply, it will not be able to heal properly because it is not able to get enough nutrients available to start the healing process. The knee specialist will explain what options there are for your knee with regards to meniscal repair or partial meniscectomy. It is hard to predict which tears can be repaired and the final decision is made at arthroscopy

Choice of treatment?

As mentioned, the recovery time for a meniscal repair is at least 3 months, while the recovery time for partial removal of the meniscus is only a few weeks. If you are in a situation where it is necessary to get back to employment as soon as possible, it may be worth talking to your surgeon about the various options available to you, and when surgery might be most suitable to you. If you have any concerns whatsoever, it is best to discuss them with your surgeon.

Coping with the Worn Knee

This booklet aims to answer questions about what can be done for the worn knee.
I believe that if you have knee problems, then it helps if you are aware of the options of treatment and how all the options are interlinked. It is the overall package of treatment that results in improvement in pain and function.

It is important to know that some people can have horribly worn looking knees and yet have minimal or no pain at all. Others who have a small worn area in just the wrong place can have substantial symptoms and limitations in what they can do.

Also, it is possible to have had worn surfaces for a long time before experiencing symptoms, then something extra happens and the knee now pops over the radar and on to the screen registering as pain and discomfort.

To read more about this, please download the booklet in pdf format.

The Female Athlete - ACL injuries

The female athlete is, unfortunately, more at risk of damaging their ACL than males, even taking into account the amount of time spent playing sport.

It goes without saying that the knee is a very complex piece of kit but it allows huge loads across it and yet functions to provide highly agile movements with fast pivoting and rapid deceleration and acceleration actions.

female-athlete-acl-injuryTo do this the knee needs power and leverage. The ligaments are static restraints in the knee and the most important part of knee function is the muscular control that makes it work. Not only do the muscles make it work but they protect against abnormal forces that may overload and damage the knee structures.

The musculature control of the knee requires a highly tuned reflex nerve control system. It is this neuromuscular control of the knee that seems to be the possible underlying factor explaining why some may rupture their ACL in an injury whereas others may not.

Essentially it mostly boils down to methods of landing pivoting and twisting. Analysing positions adopted in those activities has shown that there is a difference between how women and men control their knees. In jumping and landing, women tend to land with slightly straighter legs than men who land in a more powerful squat position with knees slightly apart.

Add to this the anatomical fact that women tend to have wider hips than men so that the sideways angle between the thigh and lower leg is greater in women, then it becomes more understandable as to why the female knee may buckle and be injured. The muscular male squat knee that is held in line on landing seems more protected than the longer thinner and less muscular knee that can buckle sideways on landing.

This theory of poor neuromuscular control has been tested in large groups of female soccer players trialing specific landing and jumping techniques in some and showing that those trained had fewer problems of ACL rupture than untrained athletes.

The importance of all this is that if a poor landing technique is recognised and acknowledged as a cause of the original ACL rupture then specific training can be undertaken which may hopefully prevent the re-injury to the same knee or new injury to the opposite knee.

Specific skills, therefore, need to be learnt in landing and jumping techniques - the principle being to land with the knee forwards and not buckling to the side – inwards or outwards. For the female, this means landing with the knees slightly apart, in a more squat and perhaps un-ladylike male posture. In addition, the principle of landing on one leg at the same time as pivoting to throw the ball should be avoided as this is possibly the most at-risk maneuver to rupture the ACL.

Acute Knee Injury

This information has been written to help steer you through the process of what happens after injuring your knee. It outlines what types on injuries there are, how a diagnosis is made, and what sort of treatment is possible.
The knee

The knee is a complex joint between the thigh bone (femur) and the shin bone (tibia) with the kneecap (patella) sitting in front. It is held together by ligaments and surrounded by a joint capsule which encapsulates the joint lubricant fluid.
What injuries are there?

The most common knee injuries are:

  • Simple sprain – by twisting or overstretching, ligaments can be stretched but remain intact
  • Torn ligaments – the anterior cruciate or posterior cruciate or collateral ligaments can be torn
  • Torn meniscus – damage to the ‘footballers cartilage’ cushion between the bones
  • Dislocation of the kneecap - ‘patella dislocation’
  • Articular cartilage injury – damage to the smooth articulating lining of the knee, the bearing surface

Injury Diagnosis

In clinic the specialist knee surgeon will speak to you and examine your knee. He will need to enquire about the exact mechanism of the injury and what has happened previously, if anything. He can then decide the appropriate management for your problem. You may need to come back once any swelling has reduced to allow the knee to be re-examined or you may need to go for further X-rays and scans (MRI).

How is the knee injured? How is each injury caused?
One of the ways to diagnose a knee injury is to look at exactly how it was damaged.



An unusual level of activity on your knees compared to normal

Injury not severe enough to cause damage

Sprain, upset of previously worn knee


Twisting movement with the foot on the ground
May feel a pop
Unable to play on

Anterior cruciate ligament rupture

Force on a bent knee either by falling or when the shin hits the dashboard in road traffic accidents

Posterior cruciate ligament partial or complete rupture

Contact sporting injury

Blow onto the side of the knee

Medial Collateral ligament (MCL) or

Lateral Collateral

ligament (LCL) sprain


Twisting injury

Knee then locking

Meniscus tear

Sudden twisting on the slightly bent knee with feeling kneecap jumping out of joint.

Patella (kneecap) dislocation

Common Injuries

Anterior Cruciate Ligament rupture
The anterior cruciate ligament stops your shin moving forward compared to your thigh bone. Normally when you twist on the knee everything turns together. When the ligament is torn the knee buckles as you try and pivot or twist, so that you no longer trust it.
Following the injury your knee may have been painful and swollen immediately, and afterwards your knee may give way again and feel less trustworthy.
When examining there may be excessive movement found in the knee. The two main tests are called the Lachman test and the Pivot Shift test.

Posterior Cruciate Ligament rupture
The posterior cruciate ligament stops your shin bone moving backwards in relation to your thigh bone. When examined with your knee at a right angle, your shin bone will sag backwards compared to your other side or the surgeon can move it excessively.
Medial or Lateral Collateral Ligament rupture or partial tear
The medial and lateral collateral ligaments lie on either side of the knee and stop it moving too much sideways. If the medial collateral ligament is damaged there may be pain on the inner side of your knee, following the line of the ligament. The knee may feel wobbly and when examined it is painful as the surgeon pulls your leg sideways. If the lateral collateral ligament is damaged there may be pain on the outer surface of your knee, with some giving way and again when examined you may feel pain as the lower leg is moved inwards.

Meniscus tear
The meniscus or ‘footballer’s cartilage’ lies between your thigh and shinbone and acts as a shock absorber when you bear weight. You have two – one on the outer lateral side and one on the inner medial side. When the knee is examined there is specific tenderness on the joint line between the bones. There may be swelling found in the knee and sometimes the knee can transiently lock as the torn fragment gets caught.

Patellar Dislocation

The patella or kneecap acts to increase the leverage of your knee when straightening your leg and it slides over your thigh bone as you bend and straighten.
Your kneecap may dislocate or feel unstable following an injury, or you may describe the feeling of your kneecap dislocating repeatedly. Usually, specialist help from a casualty is needed to put it back in its place if it doesn’t reduce spontaneously. When being examined your patella will feel unstable as if it might dislocate again. This is called the ‘apprehension test’.

What Can Be Done?

braceThere is a lot that can be done for injured knees, from simple treatments to complicated long operations. It all depends on what is injured, how badly, and what your aims and expectations are.
Options include:

  • Protection using splints and knee braces
  • Rehabilitation through physiotherapy and targeted exercises, combined with painkillers
  • Surgical repair or ‘keyhole’ surgery (arthroscopy)

ACL Injury or rupture
Usually it is difficult to cope getting back to pivoting impact type sports such as football and rugby without a good functioning ACL. The ligament does not heal very well on its own to allow fast pivoting. Therefore, typically the ligament is reconstructed using tissue from around your knee, rather like Michael Owen when he tore his ligament playing football.
This surgery is performed once the swelling from the acute fresh injury has settled and when the range of movement has returned to nearly normal. Physiotherapy is important to help regain that movement and sometimes the knee is rested in a knee brace. An MRI scan may or may not need to be arranged.
PCL Injury
Usually, the PCL can heal and surgery is not necessary. Initially, a knee brace is used to support the healing, followed by physiotherapy and strengthening exercises. However some knees will still feel unstable and then surgery can become an option – rebuilding the ligament using other tissue from around the knee. Once again it can take a long time to get back to the sport.
Collateral ligament injury
MCL sprains (medial ligament injury) usually heal well and do not need surgery. There are different grades of injury and simple injuries just need physio and time – perhaps 6 weeks to fully recover. More significant injuries may need a supportive brace for 4 – 6 weeks and it can take up to 3 months to get back to the sport after rehabilitation. It is uncommon to need surgery. However, if the ligament is completely torn in combination with tearing the anterior cruciate ligament then surgery is more often needed.

Meniscus tear

The menisci are the C-shaped cushions in your knee. They tear by being trapped between the thigh bone and the shin bone. Small tears can settle on their own over 6 weeks or so and may not need any surgery. Some tears don’t however and continue to cause intermittent pain on the side of the knee during activity. The small torn portion can then be removed at keyhole surgery (arthroscopy). Sometimes the fragment is large enough to block the knee going straight and this is called a ‘locked knee’. If this happens then more urgent arthroscopic surgery is needed and it may be possible to repair the torn cartilage back into place. Not all tears can be repaired and it is more usual to remove the small torn fragment.
The cartilage does not have a good blood supply which is why most tears do not heal. Removing the torn part does not usually cause long-term problems but it depends on how much was removed.

Patellar dislocation

There are a variety of reasons why your kneecap is more likely to dislocate or feel like it is going to dislocate or give way, and this dictates how it can be managed. Management includes the use of a knee brace to hold the kneecap in place and physiotherapy to strengthen the surrounding muscles and ligaments. Surgery can be used to change the way the kneecap moves compared to the other structures around it.
Articular cartilage injury
The articular cartilage is the smooth layer that covers the bones in your joints and stops your bones rubbing together when you move. Cartilage can be damaged in injuries or through wear and tear and can cause pain, swelling, and giving way.
To assess the damage to your cartilage you may need to have an arthroscopy. There are then several options for treating the area of damage. This may involve removing the damaged part and tidying the area up, or using other techniques such as microfracture or cartilage transplantation.

What can I do to help my knee in the future?
There are several general things that you can do to help the knee including:

  • Regular exercise including stretching to maintain a good level of fitness
  • Increase leg muscle bulk through exercise
  • Weight loss to limit loading of your knee
  • Look after your knee (if injured) with: rest, ice, compression and leg elevation
  • Wear support braces during contact sports.

General information about the knee

The International Cartilage Repair Society ICRS has an excellent section which gives information for patients about all aspects of knee injury

Mr Spalding helped edit this section in his role as part of the organisers of the ICRS Congress in 2015

Please visit ICRS Patient and Public Education Site

SONK - Patient Info