BACKGROUND: The Morel-Lavallee lesion is a closed degloving injury most commonly 
described in the region of the hip joint after blunt trauma. It also occurs in 
the knee as a result of shearing trauma during football and is a distinct lesion 
from prepatellar bursitis and quadriceps contusion.
PURPOSE: To review the authors' experience with Morel-Lavallee lesion of the 
knee in the elite contact athlete to construct a diagnostic and treatment 
algorithm.
STUDY DESIGN: Case series; Level of evidence, 4.
METHODS: Twenty-seven knees in 24 players were identified from 1 National 
Football League team's annual injury database as having sustained a 
Morel-Lavallee lesion between 1993 and 2006. Their charts were retrospectively 
reviewed.
RESULTS: The most common mechanism of injury was a shearing blow on the playing 
surface (81%). The most common motion deficit was active flexion (41%). The mean 
time for resolution of the fluid collection and achievement of full active 
flexion was 16.3 days. The mean number of practices missed was 1.5. The mean 
number of games missed was 0.1. Fourteen knees (52%) were treated successfully 
with compression wrap, cryotherapy, and motion exercises. Thirteen knees (48%) 
were treated with at least 1 aspiration, and 6 knees (22%) were treated with 
multiple aspirations for recurrent serosanguineous fluid collections. In 3 cases 
(11%), the Morel-Lavallee lesion was successfully treated with doxycycline 
sclerodesis after 3 aspirations failed to resolve the recurrent fluid 
collections; return to play was immediate thereafter in each case.
CONCLUSION: In football, Morel-Lavallee lesion of the knee usually occurs from a 
shearing blow from the playing field. Diagnosis is confirmed when examination 
reveals a large suprapatellar area of palpable fluctuance. Elite athletes are 
typically able to return to practice and game play long before complete 
resolution of the lesion. Recurrent fluid collections can occur, necessitating 
aspiration in approximately half the cases for successful treatment. 
Recalcitrant fluid collections can be safely and expeditiously treated with 
doxycycline sclerodesis.