The quadriceps femoris is the largest muscle in the human body and helps extend the knee and flex the hip. But what if things go wrong? During explosive movements, the muscle can tear, ranging from a few fibers to a complete muscle tear. This results in severe pain and often immediate loss of function in the affected leg, depending on the extent of the injury. Although the injury heals spontaneously in most cases, specific treatment is often useful and sometimes indispensable.
Anatomy Quadriceps
The quadriceps femoris consists, as the name suggests, of four muscles that run across the front of the thigh:
- Rectus femoris
- Vastus lateralis
- Vastus intermedius
- Vastus medialis
Only the first of these runs over both the hip and the knee and therefore also has an effect on both . The other three only work as an extensor of the knee. The rectus femoris is the most frequently affected of the four muscle heads. The transitions from muscle to tendon, both at the hip and the knee, are most often injured.
Muscle tear
Three typical mechanisms of a quadriceps femoris muscle tear have been described:
- Sudden braking of the leg (for example when kicking a ball)
- A violent contraction of the muscle, such as when sprinting.
- The muscle that suddenly has to deliver force in an extended position, such as when changing direction.
This quickly makes it clear that it is mainly football players, rugby players or American Football players who are affected by this condition.
Risk factors
There are some factors that increase the risk of a quadriceps femoris tear:
- Lack of proper warming up.
- Fatigue: most muscle tears occur at the end of a match or training.
- A history of quadriceps injury: after an injury, the body produces scar tissue that often has less tensile strength than the original muscle cells.
- A hyperextension posture (overextension in standing) of the knee.
Symptoms
Depending on the severity of the injury, the clinical picture will also vary. We can roughly divide quadriceps tears into three degrees, with associated complaints.
Grade I
Only a few fibers are involved. There may be mild fluid retention, spasm and some discomfort with little or no loss of strength and movement. After the brief pain at the injury, most athletes continue playing as normal. However, this can become a weak spot that can tear further later.
Grade II
A severe, sudden pain that makes walking difficult. Swelling and visible bruising may occur (after a few days). It is also often possible to feel an interruption in the muscle with the hand. Continuing to play is usually impossible and the patient has difficulty bending or straightening his knee against resistance
Grade III
A (quasi) complete muscle tear that leads to complete loss of function. The swelling can occur immediately and extensive bruising is often visible within 24 hours. There may also be a bulge that can be felt and seen with the hand when you ask to straighten the knee.
Diagnosis
Although the diagnosis is usually easy to make by listening carefully to the patient’s story, there are still some clinical tests that are important to determine the extent, exact location and functional limitations. These can help determine the chosen therapy:
- Inspection: defects such as swelling, bulges and bruising may be visible to the naked eye.
- Palpation (feeling with the hand): this allows the exact location of the injury to be better determined, as a bruise, for example, does not always appear at the location of the injury.
- Strength tests: Quadriceps function can be objectified by extending the knee and flexing the hip against resistance. To distinguish the rectus femoris from the other muscle bellies, the extension of the knee can be tested in a sitting and prone position. With a bent hip, this muscle is less active.
- Freedom of movement of joints: here the therapist can check how far one can bend the knee, for example, before resistance occurs in the quadriceps, which is thus brought to length.
If in doubt, you can opt for an ultrasound or in certain cases also an tears), to be ruled out.
Therapy
Acute
Initially, the RICE principle can be applied:
- Rest: relieve the affected leg for the first few days after the injury. It is important to continue to use the leg within the pain limits, so that the scar tissue that is formed is of good quality.
- Ice: Ice on the affected area can provide relief for the first 24 to 48 hours. Always use an intermediate to protect the skin. Apply the ice for twenty minutes and repeat every two hours.
- Compression: wrap the affected leg with a cloth, for example. Make sure it doesn’t pinch too hard or cause additional pain. This can be combined with ice application.
- Elevation: this can be done by raising the leg above the level of the heart.
These are all aimed at reducing bleeding, swelling and inflammation to promote the recovery process and flexibility. The RICE principle can possibly be supplemented with the use of anti-inflammatory drugs (NSAIDs) in the inflammatory phase (first 7 days).
Conservative
In most cases, a muscle tear heals on its own. However, specific treatment may be necessary to ensure that the new tissue is of sufficient quality to reduce the chance of recurrence.
Depending on the patient’s wishes and the extent of the injury, this can be done individually or with the help of a physiotherapist. This phase can usually be started 3 to 5 days after the incident and consists of mobilizing the knee, stretching, strength training, exercises on proprioception (‘body sensation’), balance and coordination. It is important that the exercises are integrated into patterns that patients use effectively in their sport.
Operative
In some specific cases, surgery is absolutely necessary:
- An extensive hematoma that can lead to compartment syndrome.
- A muscle tear in which more than 50% of the muscle volume is affected.
- Persistence of the complaints after several months despite conservative policy.
Here too, specific rehabilitation will be needed after the operation to prevent a new tear, and no force should be applied to the affected muscle for the first 4 weeks.
Sports resumption
This is highly dependent on the degree of the injury and the patient’s personal clinical picture. Roughly speaking, one can assume that one can gradually return to sports from 2 to 3 weeks for a grade I injury and from 4 weeks for a grade II injury. For example, one can practice non-specifically (jogging for example) or one can only train for a few weeks before participating in competitions. For more serious injuries, this can quickly increase to 2 months and it often takes 3 months before one is completely free of all complaints.
It is much more relevant to speak of a function level to be achieved before returning to sports. These RPC (‘Return to Sport Criteria’) can provide patient and therapist guidance in the evaluation of recovery:
- Strength in extended position of the affected leg comparable to the other leg, without complaints. This is both concentric (where the muscle shortens) and eccentric (where the muscle lengthens).
- Freedom of movement of the affected leg (in the hip and knee) comparable to the other leg, without complaints. Furthermore, the knee must be able to bend at least 120° with the hip extended.
- Performing sport-specific movements at competition level, without complaints.
If these criteria are met, the chance of recurrence is significantly smaller.