Working Diagnosis:
Morel-Lavallee lesion

Treatment:
US-guided aspiration, triamcinolone injection, ACE wrap, and protected weight bearing were performed to allow the Morel-Lavallee lesion
to sclerodese. Case Photo #1 Case Photo #2

Outcome:
1 week post-injury, only mild swelling, ecchymosis, and tenderness remained. Repeat US revealed minimal coagulated blood superficial to the VMO. Case Photo #3
Athlete was educated on risk of fluid re-accumulation with return to play; she accepted this risk, returning to full play.

Patient completed the season without issue. She did seek care post-season for a small amount of fluid reaccumulation, for which US-guided aspiration and compression treatments were repeated. The knee was also splinted in flexion to reduce the potential space for reaccumulation.

Author's Comments:
A Morel-Lavallee lesion (MLL) is a closed traumatic soft tissue degloving injury due to shearing force, causing abrupt separation of skin and subcutaneous tissue from the underlying fascia.3

It can present acutely or appear days after injury.4 Signs include ecchymosis, swelling, fluctuance, or skin hypermobility.4

MRI has been considered the modality of choice for evaluation. However, sports ultrasound is cost-effective and allows for dynamic evaluation while guiding intervention for immediate access.2,3 Ultrasound also allows for serial evaluation.

Once identified, the fluid should be removed; a chronic MLL may develop a fibrous capsule or pseudocyst, potentiating the tissue separation and pain.4 Compression banding and sclerosing agents are used to minimize recurrence.1,4

Editor's Comments:
Morel Lavallee lesions occur when a shear force separates the subcutaneous tissue from the fascia plane creating a space where lymphatics collect. The lesion can be frequently missed, so a high level of suspicion is needed to make the diagnosis. Common mechanisms are a bike crash with the person sliding on the pavement on their side, motor bike accident, person thrown from vehicle. They most commonly occur on the lateral hip and knee area as in this case. A common sports mechanism is sliding on turf, or ground. Ultrasound is a great inexpensive modality to diagnose it. Diagnosis can also be made on MRI.
Treatment acutely usually consists of compression and ice. Thigh and knee lesions are easier to compress. If the lesion is large, US diagnostic drainage can be performed followed by compression and ice. Serial drainages can be required as fluid may reaccumulate. Chronic lesions or lesions that continue to reaccumulate can be treated with doxycycline sclerotherapy. If it is a large lesion with over 200 cc of fluid then surgery may be required.

References:
1. Bansal A, Bhatia N, Singh A, Singh AK. Doxycycline sclerodesis as a treatment option for persistent Morel-Lavallee lesions. Injury. 2013;44(1):66-9.
2. LaTulip S, Rao RR, Sielaff A, Theyyunni N, Burkhardt J. Case report: ultrasound utility in the diagnosis of a Morel-Lavallee lesion. Case Rep Emerg Med. 2017; 3967587.
3. Nair AV, Nazar PK, Sekhar R, Ramachandran PV, Moorthy S. Indian J Radiol Imaging. Morel-Lavallee lesion: A closed degloving injury that requires real attention. 2014; 24(3):288–290.
4. Scolaro JA, Chao T, Zamorano DP. The Morel-Lavallee lesion: diagnosis and management. J Am Acad Orthop Surg. 2016;24(10):667-672.

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