ARE SPORTS INJURIES THE MOST COMMON CAUSE OF MOREL-LAVALLEE LESIONS IN THE PEDIATRIC POPULATION?

Abstract

Background:Traumatic internal degloving injury i.e. Morel-Lavallée lesion (MLL) develops as a result of blunt trauma with tangential shear forces. In the pediatric population, these have been described only as small case reports till date. Purpose: To describe the largest case series of lower extremity Morel-Lavallée lesion (MLL) in the pediatric population, to determine its etiology (especially its relationship to sports), treatment and outcomes.Methods:Retrospective study of patients <18 years presenting to a tertiary children’s hospital with MLL between 2013-2019. Demographics, clinical data, imaging features, treatment and outcomes data was collected. Descriptive statistical analysis was conducted.Results:38 patients (21 males, 17 females) having MLL with mean age 14.6 years were classified into 2 groups- hip/thigh MLL (9 patients) and lower leg MLL (29) (Table 1.1). Most common cause of lower leg MLL was sports injury (79%). Most commonly implicated sports in MLL were football and baseball(24% each). Associated injuries were seen in 9 (23%) patients. Radiographs done in 58% of patients showed no bony abnormalities. Imaging modality of choice was MRI for lower leg MLLs (72%) and US for hip/thigh MLL (67%)(Fig.1.2). MLL size was larger for hip/thigh MLL (168 cm3) as compared to leg MLL (38.6 cm3). 25 (65.8%) of MLLs were treated with conservative management,12 (31.5%) with minimally invasive methods and 1(2.6%) needed surgical management. 2/9 (22.2%) of the associated injuries required operative management. 2/38 (5%) patients were given prophylactic antibiotics. 72.4% Lower leg MLLs were treated with conservative management while intervention was needed more in hip/thigh MLLs (55.6%). Patients returned to activities at 14.3 weeks for hip/thigh MLL;9.1 weeks for lower leg MLL. 24 patients with adequate documentation demonstrated lower extremity functional score (LEFS) and pain level of 74/80 (92.5%) and 0.7/10 respectively at mean 12.5 months follow-up. Leg cellulitis was seen as a complication in one patient.Conclusion:The largest case series on MLL exclusively in the pediatric population suggests that they are more common in knee/leg region region and usually caused by sports injuries which is notably different as compared to adult population. Most pediatric injuries are treated conservatively, especially sports related MLLs. Although return to activities takes longer for hip/thigh injuries, majority of patients regain satisfactory functionality post-injury.Table 1.1.Figure 1.2.MLL imaging – MRI and Ultrasound features of MLL