Knee Injury

This injury guide identifies common knee injuries; their symptoms and treatments. Jump to section:

Sprained Knee
Runner’s Knee (Patellofemoral Pain)
Jumper’s Knee (Patella Tendinitis)
Torn Cartilage (Meniscus Tear)
PCL (Posterior Cruciate ligament) Injury
Patellar Fracture
Osgood-Schlatter Disease
Arthritis of the Knee
Knee Replacement Surgery

The ligaments in knees connect thighbones to lower leg bones and are susceptible to sprains and tears. In fact, they are among the most common sports injuries. Injuring just one ligament used to be enough to sideline someone from sporting activity. Today, however, it’s a different story – athletes can return to sports following several ligament injuries.

The knee relies on ligaments for stability. As such, any direct contact with the knee or any sharp muscle contraction leaves it exposed to injury. Injured ligaments are referred to as sprains.

Sprained Knee

There are 4 ligaments in the knee joint which keep the knee stable and protect it from injury.

  • Two cruciate ligaments in the centre of the joint – anterior and posterior cruciate ligaments (ACL & PCL).
  • Two collateral ligaments at the sides of the joints – the medial and lateral collateral ligaments (MCL & LCL).

What is a sprained knee?

A sprained knee is an injury to the knee ligaments where they become overstretched, torn or damaged. There are varying degrees of knee ligament damage. Most can be managed with self-care but a torn ligament may require surgery.

Symptoms of a sprained knee

  • Painful knee
  • Swelling and inflammation
  • Loss of movement or restricted movement
  • Instability in the knee, difficulty in bending and straightening the joint

Common causes of a sprained knee

  • Sudden rotation
  • Sudden twisting e.g. when turning quickly
  • Force applied to the knee e.g. through a rugby tackle

Sprained knee treatment

Most simple knee sprains can be self-treated at home with products available from the pharmacy such as Physicool.  NHS Choices recommend PRICE:

Protect – If any part of the body is injured, it needs to be protected from any further injury to help speed the recovery process for at least the initial 48 hours. Protection might mean limiting the use of the joint, using a knee support or bandage.

Rest – The activity which caused the injury should be stopped and the sprained knee rested for up to 72 hours. This will help the healing process. However, it is important to start movement after a few days otherwise the muscles weaken and the joint stiffens. After an initial rest period, most healthcare professionals recommend a sprained joint should be kept mobile.

Ice – Regular ice / cold therapy is recommended for the first 48 to 72 hours after the injury to help reduce pain and swelling in the knee. There is increasing concern about the use of ice packs, even wrapped in towels as they can cause damage (and even frost-bite) to the skin. A safer and more effective solution is the application of a Physicool bandage.

Compression – Swelling leads to pain, difficulty in moving the sprained knee and reduced blood flow which slows healing. Compression helps to reduce knee swelling and improve healing. The most effective way to apply and maintain compression on the knee is to use a specially designed bandage like Physicool which also draws heat from the affected area.

Elevation – Elevation assists the reduction in knee swelling by helping the excess fluid drain back into the body’s system. Ideally, the affected area should be higher than the level of the heart. For knee sprains the most effective way is to lie down flat with the leg raised and supported by pillows. There should be some support directly underneath the knee, otherwise the knee could get stiff. Elevation can be used for as long as swelling remains.

Runner’s Knee (Patellofemoral Pain)

What is runner’s knee?

As the name suggests, runner’s knee is a common ailment among runners. Runner’s knee generally affects those who put heavy stress on their knees – namely athletes, such as skiers, cyclists footballers and runners. The term ‘runner’s knee’ refers to several problems that cause pain on the front of the knee, otherwise known as patellofemoral pain.

Runner’s knee symptoms:

  • Pain around the patella, particularly where it meets the thighbone
  • Pain when bending the knee – walking, running, squatting, etc.
  • Swelling
  • Popping or grinding sensation around the injury

What causes runner’s knee?

Many factors contribute to the development of runner’s knee. These include:

  • Displacement of the kneecap
  • General injury to the area
  • Tautness or weakness of thigh muscles
  • Flat feet

Runner’s knee treatment

Runner’s knee can generally be relieved by resting, compressing  and cooling the joint. For those who suffer with flat feet, arch support shoes may be recommended by a doctor.

Protection, rest, ice, compression and elevation (PRICE) is the most recommended approach for the management of runner’s knee injuries. The aim is to minimise swelling, inflammation and pain, providing the best conditions for healing to take place.

The PRICE approach is recommended by NHS Choices:

  • Protection – protect the knee from further injury – using a support bandage if appropriate
  • Rest – stop the activity that caused the injury, and rest the injured joint or muscle. Avoid activity for the first 48 to 72 hours after injury
  • Ice – for the first 48 to 72 hours after knee injuries, apply a cooling therapy like Physicool
  • Compression – compress or bandage the injured knee to limit any swelling and movement that could damage it further
  • Elevation – keep the injured area raised and supported on a pillow to help reduce swelling

Physicool provides the key elements of PRICE in a single reusable bandage, providing ongoing protection, cooling and compression for runner’s knee. For instant pain relief wrap a size B bandage around the knee, overlapping by 50%. Cooling the knee ligaments will reduce the inflammatory response, reducing the swelling whilst aiding the healing process.

Jumper’s Knee (Patellar Tendinitis)

What is Patellar tendinitis?

Known as patellar tendonitis or patellar tendinopathy, jumper’s knee injuries are an inflammation or injury of the patellar tendon. This tissue is what connects the kneecap (patella) and the shinbone (tibia). Jumper’s knee is an overuse injury, sustained through repetitive movements to the patellar region.

Patellar tendinitis symptoms:

  • Pain bending or straightening the leg
  • Tenderness around patella
  • Tenderness around the patellar tendon
  • Swelling of the knee joint
  • Restrictive movement

What causes jumpers knee?

It’s not called jumpers knee for no reason. The most common activities that spur the condition on are jumping and running. However, any repetitive movement or exercise can bring forth its onset. Activities such as aerobics, jogging and cycling are also tied to jumpers knee injuries, causing the tendon to inflame.

Sport is not the only cause. People who have issues with alignment – hips, knees, legs, feet – are also susceptible. Excessive stress on the tendon can lead to tears, perhaps even rupture.

Patellar tendinitis treatment

Early stages may be treated conservatively using the PRICE methods. Protection, Rest, Ice, Compression and Elevation (PRICE) is the most recommended approach for the management of soft tissue injuries. The aim is to minimise swelling, inflammation and pain, to provide the best conditions for healing to take place.

A physical therapist may also recommend specific exercises and stretches to strengthen the muscles and tendons. Should the tendinitis prevail, an injection of platelet rich plasma (autologous blood injection) or a high volume saline injectio may be performed.

Torn Cartilage (Meniscus Tear)

What is Meniscus tear?

Meniscus tears, commonly known as a torn cartilage, are very common knee injuries. The meniscus is the disc that provides cushioning, maintaining balance and distributing weight across the joint. A meniscus tear restricts the knee from performing this essential function.

Symptoms of Meniscus tear

Depending on the severity of the tear, typical symptoms are:

  • Slight pain and swelling (minor tear)
  • Knee catching, popping or locking (severe tear)
  • Sharp pain in the side or centre of the knee
  • Stiffness
  • Swelling
  • Inability to straighten knee

What causes a Meniscus tear?

Torn cartilage or a meniscus tear is commonly caused by a sharp twist or turn, often when the foot is planted and the knee is bent. Activities that cause such knee injuries are sports and heavy lifting. The older you get, the more susceptible you are to this kind of tear in the knee.

Meniscus tear treatment

How a Meniscus tear is treated depends on several factors, such as the kind of tear, its location, and its severity. Age and mobility will also be a determinant. Treatments include:

  • Rest
  • Propping up the leg
  • Physical therapy
  • Surgery to the meniscus
  • Surgery to remove any meniscus

PCL (Posterior Cruciate Ligament) Injury

What is a PCL injury?

PCL stands for posterior cruciate ligament, located at the back of the knee and connecting the femur and the tibia. Injury to the PCL needs a powerful force –  falling on a knee that is bent.

PCL injury symptoms:

  • Intense pain
  • Swelling
  • Stiffness
  • Difficulty walking
  • Sensation that the knee may ‘give out’

What causes a PCL injury?

The PCL can sustain injury in a number of ways – but typically through a forceful impact.

  • Direct blow to the front of the knee
  • Twist or hyperextension of the ligament
  • A common misstep

Grades of PCL Injury

There are four different grades in which a PCL injury can be classified classified.

  • Grade I – Slight tear to the PCL.
  • Grade II – The PCL ligament is minimally torn and becomes loose.
  • Grade III – The PCL is torn completely and the knee can now be categorized as unstable.
  • Grade IV – The ligament is damaged along with another ligament housed in the knee (i.e ACL).

PCL injury treatment

It is possible for the PCL to heal on its own without surgery when it is in Grades I and II. For Grades III and IV, surgery is usually needed. In less severe cases (Grades I and II PCL tears), these knee injuries can be treated by performing certain rehabilitative exercises. Immobilisation could involve wearing a brace to restrict the knee from moving. Crutches may also be necessary to keep weight off the injury. As the swelling subsides, a course of physical therapy will help restore function to the injured knee and strengthen the surrounding muscles.

Using Physicool throughout treatment will reduce the pain and swelling, allowing the injury to heal faster.

Patella Fracture

What is a patella fracture?

A patella fracture, also known as a broken kneecap, is invariably caused by a direct blow to the knee. The injury can take two forms: either the kneecap suffers a single crack or multiple cracks.

Patella fracture symptoms:

  • Pain
  • Swelling
  • Bruising
  • Inability to bend
  • Inability to straighten
  • Inability to walk

What causes a patella fracture?

Patella fractures are commonly the result of a direct blow, such as a fall. The patella can also be injured indirectly – for instance, a violent thigh muscle contraction can pull apart the patella.

Patella fracture treatment

Depending on the severity of the injury, patella fractures can be treated in two ways: surgical and non-surgical. If pieces of the cracked patella have not been displaced, surgery may not be required. However, a cast may be required to keep the injured knee and leg straight. Healing time could be up to eight weeks and crutches are usually used for mobility.

If the patella has been displaced, surgery will most likely be required. The further displaced the patella bones are, the harder it is for knee injuries of this type to heal. Indeed, the strength of the thigh muscles, which sit atop the patella, may further encourage displacement during healing.

Osgood-Schlatter Disease

What is Osgood-Schlatter?

Osgood-Schlatter disease is one of the most frequent causes of knee pain in children. The condition generally occurs in young adolescents between the ages of 9 and 16 who partake in high impact sports that involve running, jumping and sharp changes in direction, such as football, rugby, gymnastics and basketball. Osgood-Schlatter disease is always characterised by activity-related pain that occurs a few inches below the knee-cap, or patella, on the front of the knee. The child will have swelling in the area, and tenderness to touch.

Osgood-Schlatter symptoms

  • Knee pain
  • Swelling
  • Tenderness below kneecap
  • Limping
  • Tightness of hamstring and quadriceps muscles

What causes Osgood-Schlatter?

Activities that involve running, jumping and bending pull on the tendon that connects the patella with the shinbone. Such repeated stress encourages the tendon to pull away from the shinbone, which causes pain and swelling.

Osgood-Schlatter treatment

Because most cases of Osgood-Schlatter arise in adolescents, anti-inflammatory drugs are not recommended. Some physicians will suggest complete immobilisation in a cast, but this is sometimes counterproductive, leading to other problems. The only approved treatment that has a consensus is PRICE.

Protection, rest, ice, compression and elevation (PRICE) is one of the most recommended approaches for the management of Osgood-Schlatter disease. The aim is to minimise swelling, inflammation and pain, to provide the best conditions for healing to take place.

The PRICE approach is recommended by NHS Choices:

  • Protection – protect the injured area from further injury – using a support bandage if appropriate
  • Rest – stop the activity that caused the injury, and rest the injured joint or muscle. Avoid activity for the first 48 to 72 hours after injury
  • Ice – for the first 48 to 72 hours after the injury, apply a cooling therapy like Physicool
  • Compression – compress or bandage the injured area to limit any swelling and movement that could damage it further
  • Elevation – keep the injured area raised and supported on a pillow to help reduce swelling

Physicool provides the key stages of PRICE in a single reusable bandage, providing protection, cooling and compression for the knee injury to help the healing process. A Physicool bandage can be applied to the injury and the cooling effect recharged by spraying Physicool Coolant directly onto the bandage whilst it is in position.

Physicool is a unique cotton bandage impregnated with a patented liquid which draws heat away from the affected tissues by rapid evaporation. While the deep tissues are being cooled, the simultaneous compression effects of Physicool modify the inflammatory response to soft tissue damage which helps promote healing.


What is Osteochondritis?

Also known as OCD or OD, Osteochondritis is the result of joint separation where the cartilage or a fragment of bone is inflamed and separates from the rest of the bone. In some cases, the cartilage or bone fragment stays in place. However, if it lodges in the joint space, the bone may cause much pain and hinder the joint function.

Symptoms of Osteochondritis:

  • Swelling
  • Sore or painful knee joint
  • Locking or grinding sensation
  • Limping
  • Stiffness after inactivity

What are the causes of Osteochondritis?

Despite much research into the condition, there is still no certainty to what actually causes Osteochondritis. However, experts have narrowed it down to three possibilities. Firstly, ischemia – a restriction of the bloody supply, invariably linked to trauma. Secondly, repeated stress to the knee, commonly found in those who partake in competitive sports. And thirdly, genetics – the appearance of the condition in other family members may heighten your own susceptibility.

Treatment for Osteochondritis

Options include non-surgical and surgical treatment. Non-surgical treatment is limited to skeletally immature teenagers with a relatively small, intact lesion and the absence of loose bodies. Resting, cryotherapy and abstaining from intensive sports (at least until symptoms stop) often relieves pain and inflammation. symptoms do not subside over a period of time, the use of crutches, or perhaps even surgery, may be required. The type and extent of surgery will vary based on patient age and severity of the lesion.

Knee Arthritis

What is knee arthritis?

Generally, there are three main types of knee arthritis:

Osteoarthritis is the most common; a slow, degenerative disease that is characterised by the erosion of the cushion layer  between bones. Osteoarthritis in the knee begins with the gradual deterioration of cartilage. Without the protective cartilage, the bones begin to rub together, causing pain, loss of mobility, and deformity. The majority of arthritis cases involving the knee are osteoarthritic cases. Osteoarthritis is also referred to as a degenerative joint disease and mostly occurs during middle age.

Rheumatoid arthritis (RA) is an inflammatory-based disease that degrades the cartilage lining of the joints and causes swelling that is painful and can lead to joint deformity, worsening over time. However, unlike osteoarthritis, it is likely to occur at any age, and generally affects both knees.

Post-traumatic arthritis is the result of injury to the knee. Like osteoarthritis, it can develop years after a fracture, injury or tear.

Symptoms of knee arthritis

  • Gradually developing pain in knee joint (although sudden onset is not uncommon)
  • Joint stiffness
  • Swelling
  • Weakness of knee, leading to ‘locking’ or ‘buckling’
  • Weather-sensitive degrees of pain

What causes knee arthritis?

Aside from age and genes, knee arthritis can develop from repetitive stress injuries. These kinds of injuries are synonymous with certain jobs and sports that involve stress at the knee joint: kneeling, squatting, or heavy lifting. Some sports are also thought to cause its onset, including football, tennis and long-distance running. Weak muscles surrounding the knee can lead to arthritis –regular and moderate exercise helps to strengthen these muscles and therefore decrease the risk of knee arthritis.

Knee arthritis treatment

There is no permanent cure to arthritis, the course of the disease can be modified so to lessen the damage, making the patient more comfortable so that they can still enjoy every-day activities. Treatment is most effective when begun as early as possible, before the process of deformity is far progressed, but some relief can be offered by treatment at any stage. Some of the most common recommendations include avoiding activities that make the pain worse and the application of a cooling therapy. Patients have dramatically reduced the pain and inflammation suffered by applying a Physicool bandage to the knee for 30 minutes a time throughout the day. Over the counter anti-inflammatory medications, and the use of physical therapy to promote function without risking further injury is effective for most patients. Exercises are performed that do not place additional stress or weight on the knee joint. Supportive devices like knee braces can be used to provide stability.

Knee Replacement Surgery

Physicool & Knee Replacement Surgery

Surgery is the final option but may be required to relieve symptoms. Arthroscopy is performed through tiny cuts where damaged parts of the knee can be removed. Arthroplasty is a replacement surgery where an artificial joint is used.


  1. OSTEOARTHRITIS: National clinical guideline for care and management in adults, 2008, Royal College of Physicians
  2. Barrett M, Garrett S, Mumith A, Enhancing post operative rehabilitation using a new cooling appliance in knee arthroplasty patients. Presented at EFORT (European Federation of National Associations of Orthopaedics and Traumatology 2012, awaiting publication.
  3. Lessard LA, Scudds RA, Amendola A, Vaz MD; The Efficacy of Cryotherapy Following Arthroscopic Knee Surgery, Volume 26 Number 1 July 1997 Journal of Orthopaedic and Sports Physical Therapy
  4. Adie S, Kwan A, Naylor JM, Harris IA, Mittal R, Cold therapy following total knee replacement surgery Published Online: September 12, 2012 surgery


Please Note

Some injuries can be self-treated whilst others require prompt medical attention. You should seek advice from a health professional if: the injury causes severe pain, swelling, or numbness; you can't tolerate weight on the area; the pain or dull ache of an old injury is accompanied by increased swelling or joint abnormality or instability.