EN 
NL Morel Lavalle
Morel-Lavallée was first described by a French doctor, you guessed it, Maurice Morel-Lavallée in 1863. He himself described it as a closed traumatic soft tissue injury, also known as a "degloving injury". It describes a situation in which the skin and underlying tissue become detached from the deeper structures by a powerful moment, similar to peeling off a glove. This injury is characterised by loosening of the deep fascia of the skin and the superficial layer of skin. In most cases, it involves a shearing force. This injury creates a space in which fluid, usually a mixture of blood and lymph, accumulates and can cause symptoms.
Origin of Morel Lavallee
This injury is mainly caused by high-energy trauma, most commonly seen on or around the femur. However, it can also occur after a simple bruise. It is also described that this injury can also occur in some contact sports, such as football. The most common cause in this context is a shearing force, with the knee most often involved.
In the acute phase, immediately after the injury, Morel Lavallee manifests as a smooth mobile swelling at the site of injury. In a later phase, it may present as a cystic or encapsulated accumulation of fluid. Sometimes Morel Lavallee injury often accompanies other injuries.
For this reason, other injuries may derive from the Morel-Lavallée injury. If the diagnosis of this injury is delayed or missed, it can lead to increasing difficulties in treatment and long-term consequences. If the injury is not treated correctly, it may progress to an injury that is more chronic in nature. This involves an inflammatory reaction leading to the formation of a fibrous capsule, which presents as a cyst. For this reason, prompt and effective management of Morel-Lavallée injury is important. This chronic variant is often referred to by different terms in the literature, such as Morel-Lavallée seroma, post-traumatic soft tissue cyst, post-traumatic extravasation, Morel-Lavallée effusion or a chronic expanding haematoma.
Etiology of Morel-Lavallee
Etiology is a medical term, the word comes from the Greek terms aitia (cause) and logos (study or science). In the context of medicine, aetiology seeks to explain why and how a particular condition arises.
The most common cause of a Morel-Lavallée injury is a fall or contact moment where the forces are large enough to cause actual damage. In the medical world, we also call this high-energy trauma. It most often occurs in the region of the greater trochanter, the bone area on the side of the hip. This is because this region is a bit more vulnerable to this type of injury. It is a relatively large area with a lot of skin mobility. This area, along with the buttock region, is well supplied with blood. This does not mean that it cannot occur in other areas. We also see that it can occur in places like the lower leg, especially on direct impact during sports like football. It can also occur very rarely after surgeries such as liposuction or abdominoplasty. Morel-Lavallee can occur in the following areas of our body:
Hip region (30.4%), Thigh (20.1%), Pelvis (18.6%), Knee (15.7%), Butt region (6.4%), Other regions such as lower back, abdomen and lower leg region (<5%).(1)
Epidemiology
The Morel-Lavallée injury often occurs in combination with other serious injuries, such as fractures of the upper leg (femur), pelvis and hip socket (acetabulum). Large-scale studies show that this injury is twice as common in men as in women(2). This is probably explained by men's greater exposure to severe trauma, caused by a mix of risk-taking behaviour, dangerous occupations and social expectations.So women seem to be slightly better at assessing hazards after all, but let's save that topic for another article. Because these injuries are often not recognised or recognised too late, the actual number of cases is probably higher than reported.
Pathophysiology of the Morel-Lavallée lesion
So this injury occurs due to a shearing force where the underlying fascial layers and superficial skin layers move relative to each other. This creates a cavity leading to leakage of blood, lymph and a fatty structure. The rate of accumulation depends on the amount of fluid and the number of damaged blood vessels.
The Morel-Lavallée lesion is usually visible within hours to days after the trauma. However, in a third of cases, presentation can occur months to years later. Of course, the clinical manifestations can be different depending on various factors such as the amount and rate of accumulation of blood and other fluid. But also simply consider the person's physique.
In the acute phase, the patient may experience symptoms such as:
- Pain
- Blue discolouration
- A smooth accumulation of fluid on physical examination
- Delayed discolouration of the skin, which can complicate diagnosis.
Prolonged lesions can lead to reduced skin sensitivity resulting in damage to superficial nerves. In more rare cases, secondary infections can develop, such as soft tissue cellulitis or localised abscesses. However, this is not what we often see in physiotherapy practice. Because we deal a lot with athletes in physiotherapy practice, we are more likely to see a Morel-Lavallée injury seen around the knee, caused by a direct contact moment during sports activities. This type of injury is common in contact sports, such as football or rugby, where a collision or fall leads to the typical shearing force that causes the injury.
Physiotherapy and Morel Lavallee
Ultrasound can be valuable as a tool within physiotherapy for confirming smaller Morel-Lavallée lesions. It can map the exact location, size and deformability of the lesion and confirm the suspicion. In more acute lesions (18 months) have a more homogeneous and smooth appearance. Although ultrasound is useful, other serious conditions, such as tumours, cannot always be ruled out. For detailed assessment of larger or complex lesions, MRI is clearly preferable. It provides a more accurate description of the content, size but also the stage of the injury. Acute lesions will have a different image due to a lot of fluid accumulation, while chronic lesions show a fibrous capsule.
Morel-Lavallee treatment
For small, acute lesions, conservative treatment, such as the use of compression bandages and NSAIDs (non-steroidal anti-inflammatory drugs), can be effective to reduce swelling and prevent further inflammation. Percutaneous aspiration, often performed under ultrasound guidance, is used to drain the cavity, but has a higher risk of relapse in larger lesions (>50 ml)(3,4).
For more persistent lesions, a sclerosing agent may be injected into the cavity. This irritates the inner wall of the cavity, causing an inflammatory reaction. This inflammation stimulates the formation of scar tissue, leading to the definitive closure of the cavity. This prevents further accumulation of fluid. Agents such as doxycycline or ethanol are used to close the cavity, with a success rate of about 95%(2).
For larger and complex Morel-Lavallée lesions, minimally invasive surgery may be used to shrink the space. In severe cases, open surgery may be required, sometimes combined with skin grafts. However, these treatments have little relevance to physiotherapy practice, as these complex lesions are usually already diagnosed and treated elsewhere.
In conclusion
Morel-Lavallée injury is a complex injury often caused by a severe trauma event and sometimes accompanied by underlying injuries. Early recognition is essential to avoid complications such as infection. The picture varies from souple swelling and bruising to chronic hardening. Here, imaging, such as MRI, plays an important role in the diagnosis and classification of the injury.
Treatment depends on the size, location, stage and severity of the injury. Small acute lesions can sometimes be treated conservatively with compression bandages, while larger or chronic lesions often require more invasive interventions, such as percutaneous aspiration, sclerotherapy or surgery. Minimally invasive techniques show promising results because of their efficiency and low complication risk.
In physiotherapy practice, alertness to complex soft tissue injuries, such as Morel-Lavallée injury, is important. Symptoms such as swelling and pain may resemble other conditions, such as bursitis or other disorders. Careful diagnosis is therefore important. Ultrasound can support physiotherapists in assessing the location and severity of an injury and can help rule out alternative diagnoses. If necessary, ultrasound can also play a role in referring to a specialist, such as an orthopaedic surgeon or radiologist. If in doubt, feel free to make an appointment.
Literature
1.Vanhegan IS, Dala-Ali B, Verhelst L, Mallucci P, Haddad FS: The Morel-Lavallée lesion as a rare differential diagnosis for recalcitrant bursitis of the knee: Case report and literature review. Case Rep Orthop 2012;2012:593193.23320230
2. Shen C, Peng JP, Chen XD. Efficacy of treatment in peri-pelvic Morel-Lavallee lesion: a systematic review of the literature. Arch Orthop Trauma Surg. 2013;133(5):635-40.
3. Tejwani SG, Cohen SB, Bradley JP. Management of Morel-Lavallee lesion of the knee: twenty-seven cases in the 4. national football league. Am J Sports Med. 2007;35(7):1162-7.
5. Nickerson TP, Zielinski MD, Jenkins DH, Schiller HJ. The Mayo Clinic experience with Morel-Lavallée lesions: establishment of a practice management guideline. J Trauma Acute Care Surg. 2014;76(2):493-7.
6. Shen C, Peng JP, Chen XD. Efficacy of treatment in peri-pelvic Morel-Lavallee lesion: a systematic review of the literature. Arch Orthop Trauma Surg. 2013;133(5):635-40.
