A cruciate ligament rupture (ICD code: S83) is a partial or complete tear of a cruciate ligament in the knee joint. Both the anterior and posterior cruciate ligaments can be affected. Accordingly, a distinction is made between an anterior and a posterior cruciate ligament rupture.
According to the German Federal Statistical Office, anterior cruciate ligament ruptures are diagnosed 35,000 times a year in Germany. This makes this injury one of the most common and also one of the most serious injuries to the knee joint.
The cruciate ligament is one of the two central stabilizers of the joint. The anterior and posterior cruciate ligaments are positioned centrally in the knee joint. They stabilize the joint and almost the entire movement sequence when running, walking and jumping.
Failure of the cruciate ligament results in increased lower leg propulsion. The remaining inner parts of the knee must then take over the function of stabilization. This often results in further damage to the meniscus, ligaments and joint cartilage.
You can watch the anatomy of the knee joint in the following video:
People between the ages of 15 and 30 are most frequently affected, as this age group is very active in sports. Women have an injury rate up to eight times higher than men. Possible causes for this include
- hormonal influences,
- different anatomical differences and
- different training routines
are discussed. Every third cruciate ligament rupture is accompanied by a meniscus injury . Accompanying injuries to ligaments and joint cartilage are also common.
In most cases, a cruciate ligament rupture is the result of a sports accident, particularly in sports such as
- soccer,
- handball and
- skiing.
However, accidents at work and traffic accidents are also common causes of cruciate ligament ruptures. Injuries to the anterior cruciate ligament often occur without direct external influence (> 70 % of injuries).
Typically, a cruciate ligament rupture is caused by unexpected changes of direction. High acceleration forces - e.g. when skiing - lead to an external rotation of the lower leg on the bent knee joint and at the same time to an opening of the joint on its inner side (so-called valgus stress). The otherwise stable ligament can no longer withstand the forces acting on it.
Also
- inward rotations with tilting outwards (so-called varus stress) as well as
- strong stretching and bending movements
can also lead to a cruciate ligament rupture.
© Henrie / Fotolia
The classic injury mechanism is a sudden and unexpected change of direction with twisting of the body and a simultaneous stop in walking speed. The foot is fixed to the ground. Contact with an opponent is not necessary. We speak of a fixed-standing twisting trauma.
The rupture of the cruciate ligament manifests itself
- Severe pain and
- a tearing or shifting sensation in the knee, which can be heard as a cracking sound.
A haematoma quickly forms: there is a feeling of tension and pain on exertion.
Without immediate ice and compression treatment, the knee swells up quickly due to
- Haematrosis due to tearing of the arterial supply to the anterior cruciate ligament and
- bleeding into the peripheral soft tissue due to capsular injuries.
Knee joint effusion(joint effusion) can also occur.
Those affected are usually unable to continue their sporting activities.
These acute symptoms of a torn anterior cruciate ligament usually subside within 10 to 14 days. The joint can then initially be loaded normally again. The affected person often experiences a feeling of insecurity and instability in the knee joint as the condition progresses. The load-bearing capacity of the joint also increasingly decreases in everyday life. This is characterized by
- Insecurity when walking,
- spontaneous buckling of the knee joint,
- load-dependent pain and
- inhibition of extension and flexion of the knee joint.
At some point, the persistent instability leads to consequential damage to the meniscus and joint cartilage. Up to 80 percent of those affected suffer a torn meniscus five to ten years after tearing their cruciate ligament. This means that a further stabilizer of the joint is injured. This increasing instability often leads to osteoarthritis later on.
To diagnose a torn anterior cruciate ligament, the first step is to take a medical history, i.e. a consultation with the doctor.
Medical history interview
As part of the medical history, the doctor will ask the patient the following questions:
- Is the current knee trauma actually a first-time accident or was it preceded by a first-time accident?
- Was the knee already swollen after previous twisting traumas, had there been a crash, did the patient have to stop a sporting activity due to an acute injury to the same knee joint?
- Was a puncture performed with blood being drawn?
- Was the injured person given a plaster cast or a bandage?
- Was the knee later no longer as stable as the healthy knee?
- Was there repeated swelling with minor twisting in the further course?
The 5 most important questions about the symptoms:
- Severe pain from deep within the joint?
- Crackling (very reliable sign if positive, but can occasionally go unnoticed)?
- Swelling, effusion (1-24 hours after the trauma)?
- Discontinuation of play or sport (skiers can occasionally still complete runs due to the cold effect)?
A positive answer to some of these questions indicates a previous injury to the anterior cruciate ligament. A feeling of instability with a tendency to subluxation is evidence of chronic anterior cruciate ligament insufficiency.
© westfotos.de / Fotolia
Clinical examination of the knee joint
The doctor will thoroughly inspect and feel the patient's injured knee (palpation). Fresh skin changes indicate the type and intensity of the injury. At the latest, the discovery of injury and surgical scars should prompt the examiner to search for their anamnesis.
The malalignment of leg axes is of great prognostic significance. Varus malalignments in combination with posterolateral capsular ligament injuries lead to instability with considerable handicap for the patient.
The active and passive movement test rounds off the physical examination. The doctor uses palpation and certain movement patterns to check
- the pain points around the knee joint and
- the function of the ligaments.
Imaging procedures
In addition, imaging procedures are usually used, such as X-ray examinations and magnetic resonance imaging(MRI). There are restrictions for patients with previous knee joint operations with metal parts.
Standard X-rays, preferably with comparison of the uninjured side, allow the assumption of an old cruciate ligament injury due to
- osteophytes,
- incipient flattening of the condyles,
- narrowing of the joint space and/or
- clumping of the cruciate ligament cusps
can be confirmed.
Another examination from the field of radiology is scintigraphy. In recent years, it has become increasingly important for the detection of "active" cartilage/bone lesions in the knee joint. For example, "hot spots" indicate active chondromalacic foci with cell death.
Chrondromalacia means cartilage damage to the joints. Unstable knee joints with hot spots should be stabilized as far as possible in order to slow down the progression of these cartilage processes.
X-rays can be used to determine whether the bony structures have suffered damage after a cruciate ligament rupture © angkhan | AdobeStock
A torn cruciate ligament can generally be treated both conservatively and surgically.
Conservative treatment methods include
- Physiotherapy to stabilize the knee joint and build up muscles, and
- pain therapy and
- cold therapy.
The mostly younger patients very often wish to continue to be active in sports. In principle, this is also possible without a functioning anterior cruciate ligament if the knee joint is well muscled.
But don't be fooled: Due to possible consequential damage, five years after a cruciate ligament rupture, only around one in two people affected can actually continue to play sport without restriction. In addition, long-term and often decades-long intensive muscle building is rather unlikely.
The anterior cruciate ligament should therefore be surgically stabilized following a cruciate ligament rupture as part of a cruciate ligament operation. Incidentally, this not only applies to young adults, but also to children and older people.
Modern arthroscopic techniques have completely replaced the older technique, in which the entire joint has to be opened. Techniques in which the torn cruciate ligament is stitched back together are also outdated today.
Instead, the injured cruciate ligament is replaced by the body's own tendon. You can see the cruciate ligament plastic surgery procedure in the video:
When should surgery be performed for a torn cruciate ligament?
The ideal time for replacement surgery after a torn anterior cruciate ligament is controversial. In order to avoid complications during the operation, many surgeons wait at least four to six weeks for isolated cruciate ligament injuries.
If the body's own healing process has not yet started in the injured joint, the operation can also be performed immediately after the cruciate ligament rupture.
Accompanying injuries also often determine the right time. Meniscus injuries in particular are common and should be sutured as soon as technically possible.
What material is used during the operation?
The patellar tendon and the semitendinosus tendon are the main materials that can be used for replacement plastic surgery in the event of a cruciate ligament rupture. The use of the patellar tendon is the gold standard. Various surgeons also primarily use the quadriceps tendon.
All transplants can cause problems during surgery. The correct placement of the replacement tendon in the knee joint is really crucial. It must be positioned as precisely as possible in the same place as the original cruciate ligament. This is the only way to ensure that the knee joint can withstand almost full load and movement after a cruciate ligament rupture. Correct positioning is technically demanding for the orthopaedic surgeon.
How can the operation be performed for a torn cruciate ligament?
A single tendon strand is usually inserted into the knee joint as a transplant. This is known as the single bundle technique.
However, this does not correspond to the anatomical specifications: the cruciate ligament actually consists of three individual main fiber bundles. These are intertwined in a helical fashion. Biomechanical studies suggest that the anteromedial and posteromedial bundles provide the main guidance.
For this reason, a more advanced surgical technique has been developed in recent years in which a single bundle is no longer used. Instead, two somewhat narrower grafts are used, which are inserted more along the original course of the two fiber bundles.
This modern double bundle technique is primarily intended to prevent the unpleasant post-operative rotational instability that can occasionally remain after conventional techniques.
However, this advantage - which has not yet been verified with certainty - is offset by
- the higher surgical outlay,
- procedural complications,
- higher costs and
- costs and increased effort in the event of revision
are opposed to this.
This technique is currently still the subject of scientific debate and is not yet a routine procedure. Nevertheless, this therapeutic approach is extremely promising and represents a serious alternative in modern cruciate ligament surgery.
The severity of the knee injury is also reflected in the follow-up treatment after a cruciate ligament rupture. Rehabilitation is the most important measure to ensure the long-term success of the operation.
Postoperative treatment after a cruciate ligament rupture must be carried out in a functional manner at an early stage. The aim is to achieve full extension of the knee joint as quickly as possible and a flexion range of up to 120°.
The ability to work is restored after 14 days, at least for office work. Proper and time-consuming rehabilitation takes considerably longer. It can take eight to ten weeks or even longer to complete.
This is almost always followed by further individual rehabilitation training. For example, light running training is usually only possible after three months. It is advisable to resume knee-straining sports after six months at the earliest.
Rehabilitation is important for good results after cruciate ligament rupture treatment © AYAimages | AdobeStock
The long-term prognosis for correctly performed cruciate ligament replacement surgery is good overall: the stability of the joint is ensured for years.
However, the development of osteoarthritis in the injured joint cannot always be prevented. Despite a successful operation, it depends crucially on the existing previous damage or the accompanying meniscus injuries.
However, only a stabilized joint has a chance of being truly protected against this.
The risk of suffering a cruciate ligament rupture can be minimized by means of
- Strength,
- proprioception and
- coordination training
can be prevented. This makes it possible to optimize everyday or sport-specific movement sequences in unfamiliar stress situations.
The training of protective reflexes through balance exercises for stabilization in extreme situations is very helpful. These include unforeseen events such as tripping or high muscular-coordinative demands, such as a ski fall.
The trained muscles surrounding the knee joint are able to absorb large loads if they are activated in a timely and correctly coordinated manner. In the event of excessive strain or unexpected forces, the strain is transferred directly to the knee ligaments. Gaining time to give the muscle the chance to intervene is the most important protective factor in this phase to counteract traumatic overload and damage such as a cruciate ligament rupture.
In addition to preventive training, prophylactic knee braces are also discussed here to prevent cruciate ligament ruptures. For the design and use of a prophylactic orthosis (brace) to make sense, it must be tailored to the sport being practiced. The movement patterns and injury mechanisms can differ greatly in different sports.
For example, sports such as soccer or American football cannot be compared with ice hockey. Soccer and American football require an increased fixation of the leg on the surface (cleats). Ice hockey, on the other hand, aims for reduced friction with less fixation on the surface (ice).
In the meantime, more than 100 prophylactic splints have been fitted to ice hockey players as part of our 10-year prospective study. The results have been consistently positive. Based on our experience with the national ice hockey team, the use of orthoses as prophylaxis against cruciate ligament ruptures and other injuries in this sport is to be recommended.
