Fractures in the knee area (or knee fracture) can affect the following structures: kneecap, femoral knuckles (also called femoral condyles), tibial plateau, bone ridge on the shin (eminentia intercondylaris) and tibial bulge (tuberositas tibiae).
The injuries can be caused by direct or indirect force. Shin and kneecap fractures account for 1% of all skeletal fractures. Injuries to the femoral condyles represent 4% of all femoral fractures.
Contents
Causes of a knee fracture
Fractures of the knee can have the following causes:
- force (direct or indirect),
- chronic stress,
- favored by pathological circumstances, such as a bone tumor (osteosarcoma).
The knee structures can break due to direct or indirect force, followed by pain and edema.
- The fracture of the kneecap is usually caused by a direct blow, e.g. in a car accident, a fall on the bent knee or tense quadriceps with a half-bent knee joint (e.g. a misstep or fall).
- Fractures of the femoral condyle (kneeling area of the femur) occur during vertical loading in the valgus position (inwards) or varus position (outwards).
- The fracture of the ridge of the bone, which protrudes between the shin joints, is caused by a direct blow to the upper shin with the knee bent, as in a fall from a bicycle. It can also occur when the knee joint in the varus or valgus position is overstretched (e.g. vehicle collisions or sports accidents); Fractures with separation of the ridge of the bone occur mainly in children between 8-14 years, but can also affect adults.
- The fracture of the shin bump usually occurs in sports with a high proportion of jumps, e.g. basketball, diving, gymnastics and football. Men are affected more often than women.
- The fracture of the shin plateau (kneeling, upper part of the shin) is caused by a traffic accident; a fall from a motorcycle or from a great height can break through the shin plateau. In the elderly or osteoporosis patients, even a slight amount of force may be sufficient. The injured person is usually able to load the leg with body weight.
Symptoms of a knee fracture
When examining the patient with suspected fracture, attention should be paid to swelling, bruising and stiffness (restriction of movement).
The patient is asked to lie on his back and raise the stretched leg against gravity to check if this movement is possible. With a displaced kneecap fracture, the patient is unable to lift the lower limb.
Fracture types
Kneecap fractures
The patient feels pain above the kneecap.
He can only stretch the knee joint under great pain or not at all.
Fractures of the femoral condyle
The patient feels pain on the femur, at the level of the internal or external articular cartilage; often a bruise is noticeable.
The affected person is not able to shift the body weight to the broken leg.
Fractures of the ridge
of the bone The patient has severe, stabbing pain and probably a bruise on the knee.
It is possible that the anterior cruciate ligament at the base of the tibia detaches (avulsion).
Fractures of the shin bump
Patients feel pain on the anterior shin, about 2-3 cm below the articular surface.
With severe fractures, it is not possible to stretch the knee joint.
Fractures of the tibial plateau
Patients have a swollen, painful knee (indoor or outdoor).
Up to 30% of these fractures are associated with injuries to the knee ligaments (inner ligament or anterior cruciate ligament in case of fracture of the plateau interior, injury to the outer ligament and posterior cruciate ligament in case of fracture of the plateau outer area). Differential diagnosis The doctor must exclude the following injuries and diseases:
- knee dislocation,
- Bruise
- Osgood-Schlatter’s disease,
- peripheral vascular injuries.
Diagnostic imaging X-ray
The knee is x-rayed from the front, from the back, from the side and in an oblique direction.
The four different perspectives are extremely helpful in detecting fractures in the knee area.
The oblique X-ray image shows particularly good cracks in the tibial plateau and oblique injuries of the femoral condyle.
If the Ottawa rules are observed during the X-ray of the knee, costs and waiting times can be shortened. Based on these rules, X-rays are performed in the following cases:
- the patient is at least 55 years old,
- stiffness of the head of the fibula,
- isolated stiffness of the kneecap,
- impossibility to bend the knee by more than 90°,
- Impossibility to fully load the knee.
Computed tomography
CT may be necessary to assess the level of joint depression of the tibial plateau.
A CT scan is very helpful in patients with multiple trauma, especially if it is not possible to perform the X-rays in all perspectives. The
Magnetic resonance imaging has the advantage of also displaying soft tissue and is therefore ideal for suspected ligament, meniscus and bursa injuries.
In the case of cartilage-bone injuries (osteochondral injuries), this examination procedure shows the extent of the damage.
A microfracture can only be detected by MRI.
What can be done? Treatment options for a knee fracture
The treatment of undisplaced fractures with intact extension movement provides for plaster cast or splint (orthosis), forearm crutches and partial load for 6 weeks. In the case of displaced fractures or extensor deficit of the knee joint, there is an indication for surgical intervention to set up (reposition) the fracture and for internal attachment by tension strapping (cerclage).
In the case of severe fractures (debris fractures), a patellectomy may also be required, which means the partial or total removal of the kneecap, which is replaced by the patellar quadriceps tendon.
Patients with open fractures should undergo antibiotic treatment and see an orthopedist to remove dead tissue and foreign bodies.
The fracture site must be carefully cleaned to prevent inflammation.
Fracture of the femoral condyle
There are several types of injury here: above (supracondylar) or in the area of the articular cartilage (percondylar).
If the fracture is located inside the bone, the spongiosa is affected, a sponge-like system of fine bone balls; the outer part of the bone is compact.
Since nerves and arteries are very close to the fracture gap, a thorough examination of the nerves and blood vessels must be carried out.
Surgical intervention can be dispensed with only in the case of incomplete or undisplaced fractures; open, displaced or combined with nerve and vascular injuries bridge must be treated surgically.
Fracture of the shin ridge
In the case of an undisplaced fracture (with a stable knee joint), it is sufficient to immobilize the knee by plaster cast or splint.
In the case of unstable knee joint, complete separation (avulsion) of the shin ridge or displaced fracture, the orthopedist must decide whether surgical care is necessary.
Fracture of the tibial bump
In the case of undisplaced fractures, immobilization of the knee joint is sufficient.
If the fracture is displaced, an operation for setup and fixation may be necessary. Fracture of the tibial plateau surgically treated with nails and plate.
Fracture of the tibial plateau
In the case of undisplaced fractures, the leg is plastered and must not be loaded.
In the case of displaced fractures (with joint prolapse), an orthopaedist must be consulted for installation and attachment.
If the joint prolapse is more than 3 mm, surgical intervention is required.
The aim of the treatment is the stabilization, reposition of the knee joint, as well as flexibility and freedom from pain in order to minimize the risk of post-traumatic osteoarthritis.
Medication for knee fracture
Painkillers (analgesics), opioids and nonsteroidal anti-inflammatory drugs (NSAIDs) are the right medications for the pain associated with a fracture.
The NSAIDs are generally used to relieve mild to moderate pain. Ibuprofen is certainly the first choice for the initial treatment. Alternatives are: flurbiprofen, ketoprofen and naproxen.
Naproxen and ketoprofen are active ingredients that can be taken for mild pain if there are no contraindications. The effect is based on inhibition of the inflammatory reaction and pain; this is done by reducing the activity of prostaglandin synthesis.
Analgesics
Paracetamol (paracetamol, ben-u-ron, etc.) is intended to provide relief to the patient who has suffered a bone fracture.
Paracetamol is the best remedy when patients are allergic to aspirin or NSAIDs.
Opioids
To relieve very severe pain, the following active ingredients can be combined:
- oxycodone and paracetamol,
- oxycodone and aspirin,
- Morphine sulfate.
Complications of knee fracture
The complications concern injuries of the nerves and blood vessels:
- It is possible that displaced fractures in the lower part of the femur or shin plateau injure the artery of the hollow of the knee.
- In the case of fractures on the upper part of the fibula, the fibula can be affected.
- There may be compartment syndrome of the lower extremity, which has the following symptoms: pain with passive movement of the muscles concerned, paresthesia, pallor and weak pulse rate. The compartment syndrome causes by definition an increased blood pressure in the muscular lodge (compartment).
When palpated, the affected area is harder, which can be helpful in diagnosis. But a soft muscle does not automatically exclude compartment syndrome. If this pathology is suspected, it is necessary to immediately consult an orthopedist and measure the pressure in the affected area. If compartment syndrome is not treated, it can lead to permanent disability. - infection of soft tissues,
- osteomyelitis after an open fracture,
- delayed fracture healing (consolidation),
- Fat embolism
- avascular necrosis,
- Thrombophlebitis
- post-traumatic arthrosis or stiffness of the knee joint,
- Cartilage disease of the kneecap (Chondromalacia patellae).
Physiotherapy and rehabilitation for knee fractures
After a knee fracture, exercise therapy exercises are fundamental to allow complete flexion and extension of the knee joint and to regain muscle strength and balance.
Initially, the physiotherapist moves the knee joint passively, later the patient must actively perform the movements.
Balance is regained with exercises on proprioceptive boards or by standing on the broken leg.
How long are the recovery times? The prognosis for recovery
A good prognosis exists for fractures of bone ridge of the tibia and tibial bump.
The healing times for injuries to the tibial plateau and the femoral condyles are longer.
20% of patients with fractures of the tibial plateau show residual stiffness of the knee joint within one year.
