Zwei Männer stehen auf einem Dach und machen Wechselsprünge. Der Mann im Vordergrund trägt eine SofTec® Genu, eine stabilisierende und muskelaktivierende Knieorthese von Bauerfeind, am rechten Knie.

Unhappy triad is a knee injury that results from a chain of separate injuries in the knee joint. As the name suggests, there are three types of injuries involved here – an injury to the medial collateral ligament, the meniscus (a cartilage in the joint), and the cruciate ligament. This combined injury usually occurs when the knee is twisted, something that happens particularly often when skiers get snagged in their skis. Treating an unhappy triad is a difficult process, whereby the exact course of treatment depends on several factors, such as the severity of each injury. Knee orthoses are used here, as they stabilize and reduce pressure on the knee joint during the healing process.

Causes of an unhappy triad

Illustration der Anatomie des Knies bei einem "Unhappy Triad". „Unhappy Triad“ heißt übersetzt so viel wie „unglückliche Triade (Dreier)“ – und das ist diese Knieverletzung auch: eine Verkettung von unglücklichen Verletzungen im Kniegelenk. Dabei sind das Innenband, der Meniskus (ein Knorpel im Gelenk) und das Kreuzband geschädigt. Die Kombinationsverletzung entsteht meist, wenn sich das Knie verdreht.

Accidents and certain types of athletic activity often lead to combined injuries in the knee joint. An unhappy triad consists of the following injuries:

  1. Tear of the anterior cruciate ligament (ACL)
  2. Tear of the medial collateral ligament. (MCL)
  3. Damage to the medial meniscus

The injuries usually occur when the knee is slightly bent, the leg is in a knock-kneed position, and the knee rotates outwards while the lower leg remains immobile (valgus stress). This unfortunate combination of positions rarely occurs in normal situations, which is why skiers and athletes who play contact ball sports such as football and handball often suffer such injuries. Martial artists also frequently suffer an unhappy triad during matches.

Symptoms of an unhappy triad

Whether it’s skiing or football – challenging athletic activities can cause the knee to twist more quickly then most people realize. Sometimes a loud “pop” is heard – the sound of ligaments tearing. Things happen fast after that: The knee swells up extensively and becomes extremely painful, and the injured person cannot bend or stretch their leg because of all of the pain and swelling. The knee also often twists when the injured person attempts to stand or walk. This twisting under strain is referred to as the “giving-way phenomenon.” A bruise generally develops, although this might not happen until a few days after the injury.

Twisted knee: now what?

The knee should be elevated and cooled immediately if an unhappy triad is suspected. As a provisional measure, the knee joint should be splinted in the extended position, and weight-bearing should absolutely be avoided.

Diagnosing an unhappy triad

In order to make the diagnosis, the orthopedic or sports physician will first ask for an exact description of how the injury occurred. Based on this description, they will decide whether to consider an unhappy triad. Then, a physical examination is performed to evaluate the knee joint structures. Magnetic resonance imaging (MRI) may also be used to assess the condition of the ligaments, menisci and cartilage.

Treating an unhappy triad

Eine Physiotherapeutin führt Therapieübungen mit einem Patienten in einem Krankengymnastikraum durch. Der Patient trägt eine SecuTec® Genu in der Farbe grün am rechten Knie. Dies ist eine stabilisierende Knieorthese von Bauerfeind für sicher geführte Bewegungen. Die SecuTec Genu stabilisiert das verletzte Knie oder schützt es vor schädigenden Fehlbewegungen, um den Heilungsprozess zu unterstützen.

An unhappy triad is difficult to treat because it is a combined injury that affects several structures in the knee joint rather than just one specific structure. Many medial ligament injuries can be successfully treated conservatively (i.e. without surgery) using medication, physiotherapy, medical supports or knee braces (orthoses) and targeted muscle strengthening. However, cruciate ligament and meniscus tears generally do not heal on their own. In certain circumstances, surgery with subsequent rehabilitation measures may be required.

In the case of meniscus damage, the course of treatment depends on the extent of the injury. Either conservative or surgical treatment measures will be used, depending on the severity and location of the meniscus tear. During unhappy triad surgery, the torn cruciate ligament is sutured or replaced and torn portions of the meniscus are removed.

Most unhappy triad surgeries are conducted using arthroscopy. This requires only small skin incisions, which lowers the risk of infection and reduces the time it takes for surgical wounds to heal. It is highly recommended for surgery to be followed by a regeneration phase, comprising physiotherapy and the use of orthoses to stabilize and relieve the knee joint. The orthosis protects and relieves the knee joint and also allows a gradual increase in weight-bearing.

Complications resulting from an unhappy triad

If structural instability is accompanied by functional instability that cannot be compensated by muscle strengthening exercises, then surgery is generally necessary. Otherwise, osteoarthritis of the knee might be the long-term consequence. Without surgery, the cartilage would be exposed to excessive strain and wear down. If such cartilage is then no longer available to serve as a protective layer, the bones will rub against each other, which will lead to severe pain and further wear-related conditions.

Knee joint instability may go unnoticed for some time if the individual injuries in an unhappy triad are only slight. If the orthopedic physician decides to pursue a conservative course of treatment, it therefore makes sense to re-examine the knee joint’s stability after a few weeks.

Orthoses that support the knee joint

Orthoses play an important role in the treatment of an unhappy triad. During conservative treatment or after surgery, the SecuTec Genu and SofTec Genu orthoses stabilize the knee joint in the healing phase. SecuTec Genu is easy to put on, lightweight, stable and offers excellent wearing comfort. In case of swelling in the knee joint after surgery, the SecuTec Genu can be adapted using versatile knee pads.

SecuTec Genu

SecuTec® Genu

Stabilizing knee orthosis for securely guided movement
SecuTec Genu stabilizes the injured knee and protects it from damaging incorrect movements to boost the healing process.

The special feature of the SofTec Genu is its combination of orthosis and knitted fabric. Apart from its stabilizing function, this also helps to activate the muscles. Additionally, the knitted fabric’s compressive effect and the massage exerted by the pad accelerate the absorption of effusions and edematous swellings.

SofTec® Genu

Stabilizing and muscle-activating knee orthosis
Here’s what SofTec Genu offers: two lateral joint splints prevent harmful movements. The “smart” hinges can be adjusted precisely to your knee’s rotational axis.

In both orthoses, the hinges and thus the range of motion can be extended in small increments to match the treatment progress. This makes it possible to individually adjust the stress on the knee in the course of recovery. SofTec Genu is particularly well suited for patients who wish to return to athletic activities quickly and/or for patients who would like to use the stabilization offered by an orthosis without significant limitations.