Morel-Lavallée-Like Periosteal Degloving Lesion of the Tibia Following Trauma: A Novel Observation

Abstract

Morel-Lavallée lesion (MLL) is a closed degloving injury resulting from the separation of the subcutaneous tissue from the underlying deep fascia due to shearing forces. It most commonly occurs around the pelvis, hip, and thigh. We describe an unusual post-traumatic lesion resembling an MLL but occurring at the periosteal interface of the tibia. A 49-year-old man presented with a localized swelling over the upper anterior aspect of the right leg that developed two months after a blunt injury sustained while kick-starting a motorcycle. Physical examination revealed a firm, mildly tender swelling over the proximal tibia. Ultrasonography demonstrated a well-defined subperiosteal anechoic collection with minimal heterogeneous echogenic contents, consistent with an organized chronic subperiosteal hematoma. Unlike a conventional MLL, the lesion was confined to the plane between the tibial periosteum and the overlying fascial-soft tissue envelope, without intramuscular extension or internal vascularity. Plain radiographs showed no osseous involvement. Ultrasound-guided aspiration confirmed the diagnosis of chronic hematoma. This case highlights a previously undescribed Morel-Lavallée-like periosteal degloving lesion of the tibia resulting in a chronic subperiosteal hematoma. Recognition of this atypical injury pattern and its characteristic ultrasonographic appearance may facilitate the accurate diagnosis of chronic post-traumatic tibial swellings and help avoid unnecessary investigations.

Introduction

Morel-Lavallée lesion (MLL) is a closed degloving injury produced by tangential shearing forces that separate the subcutaneous tissues from the underlying deep fascia, creating a potential space that may fill with blood, lymphatic fluid, or necrotic debris [1,2]. The lesion is classically described around the pelvis, hip, and proximal thigh, where abundant mobile subcutaneous tissue predisposes to fascial separation following trauma [1]. Delayed presentation with a chronic organized collection is well recognized and may pose a diagnostic challenge. Musculoskeletal ultrasonography has emerged as a valuable bedside tool for evaluating post-traumatic soft tissue swellings because it can identify the anatomical plane of the lesion, characterize its internal contents, and assess vascularity [3]. Although atypical locations of MLL have occasionally been reported, involvement of the periosteal interface of the tibia has not been well documented [4]. We report an unusual case of a chronic post-traumatic subperiosteal hematoma over the anterior tibia that developed following a shearing injury and demonstrated imaging features resembling an MLL. The lesion was confined to the plane between the tibial periosteum and the overlying fascial-soft tissue envelope rather than the conventional deep fascial-subcutaneous plane. This case highlights a possible Morel-Lavallée-like periosteal degloving lesion of the tibia and underscores the role of ultrasonography in distinguishing chronic post-traumatic tibial swellings from other soft tissue and osseous pathologies.

Case presentation

A 49-year-old man presented to the Physical Medicine and Rehabilitation (PM&R) outpatient department with a localized swelling over the upper anterior aspect of his right leg that had been present for three months. Five months prior to presentation, he sustained a blunt injury while kick-starting his motorcycle when his foot slipped and the kick-start pedal forcefully struck the anterior aspect of his shin. He experienced immediate localized pain but did not notice any swelling or skin changes at that time. Approximately two months after the injury, he gradually developed a localized swelling over the anterior tibial region, which subsequently remained stable in size. The patient denied any history of open injury, recurrent trauma, fever, weight loss, night sweats, local redness, discharge, or other constitutional symptoms. He had no history of bleeding disorders, anticoagulant or antiplatelet use, previous surgery involving the affected limb, or similar swellings elsewhere. There were no associated sensory symptoms, weakness, gait disturbances, or functional limitations related to the affected lower limb.

Physical examination revealed a well-circumscribed (4.5 × 3 cm; length × width), firm swelling over the upper anterior aspect of the right tibia (Figure 1).

Figure 1. Traumatic swelling (red arrow) over the upper anterior aspect of the right tibia.

The swelling was mildly tender on palpation, without associated warmth, erythema, or skin discoloration. Neurological examination (motor, sensory, and deep tendon reflexes) of both lower limbs was normal. The ranges of motion of the knee and ankle joints were full and painless. The swelling was non-fluctuant, non-compressible, and non-pulsatile, with no bruit or thrill. There was no regional lymphadenopathy. The patient had a normal gait and was able to bear weight without pain or difficulty.

Diagnostic ultrasonography revealed a well-defined subperiosteal collection (anechoic) over the tibial shaft (4.5 × 3 × 2.5 cm; length × width × depth) with very few heterogeneous echogenic contents, consistent with an organized subperiosteal hematoma (Figure 2A-2B).

Figure 2. Ultrasound image of the swelling.

(A) Ultrasound image (short axis to tibia) showing an anechoic area (white star marked) suggestive of hematoma and muscular structure as TA. (B) Ultrasound image (short axis to swelling) showing an anechoic area (white star marked) with very few heterogeneous echogenic contents within it, consistent with an organized subperiosteal hematoma. (C) Ultrasound image (long axis to swelling; upper end) showing an anechoic area (white star marked) and that the lesion was confined to the plane between the periosteum (below) and the overlying fascial-soft tissue envelope (unlike a typical Morel-Lavallée lesion where the lesion is confined to the deep fascia and subcutaneous tissue) (yellow arrow). (D) Ultrasound image (long axis to swelling; lower end) showing an anechoic area (white star marked) and that the lesion was confined to the plane between the periosteum (below) and the overlying fascial-soft tissue envelope (unlike a typical Morel-Lavallée lesion where the lesion is confined to the deep fascia and subcutaneous tissue) (yellow arrow).

TA: tibialis anterior

The lesion was confined to the plane between the periosteum and the overlying fascial-soft tissue envelope (unlike a typical MLL where the lesion is confined to the deep fascia and subcutaneous tissue), without intramuscular extension (Figure 2C-2D). Color Doppler examination showed no internal vascularity. Plain radiographs excluded bony abnormalities or involvement.

Ultrasound-guided aspiration of the lesion yielded altered blood products, confirming the diagnosis of a chronic hematoma. Based on the history of blunt shearing trauma and the characteristic ultrasonographic appearance, the lesion was considered a Morel-Lavallée-like periosteal degloving lesion resulting in a chronic subperiosteal hematoma at an atypical anatomical location.

The differential diagnosis of a Morel-Lavallée-like lesion includes bursitis, abscess, fat necrosis, epidermoid cyst, ganglion or synovial cyst, and benign or malignant soft tissue tumors. Careful correlation of the patient's clinical history, anatomical location, physical examination, and imaging findings is essential to distinguish these entities and establish an accurate diagnosis, particularly when the lesion presents at an atypical site. Additionally, the mechanism of injury provides an important diagnostic clue, as a history of shearing trauma strongly supports the diagnosis and helps differentiate it from other soft tissue lesions.

Discussion

The most striking feature of the present case is the unusual anatomical plane of the lesion. Although MLLs classically involve the separation of the subcutaneous tissues from the underlying deep fascia, a similar shearing mechanism appears to have operated in this patient at a different anatomical location [1,2]. Owing to the minimal soft tissue coverage over the anterior tibia, the traumatic force generated by the motorcycle kick-start pedal may have been transmitted directly to the fascial-periosteal interface, resulting in separation at this level and the subsequent formation of a chronic subperiosteal hematoma.

Ultrasonography demonstrated a well-defined collection confined to the plane between the tibial periosteum and the overlying fascial-soft tissue envelope, without intramuscular extension or evidence of osseous involvement [5]. The delayed appearance of the swelling, chronic persistence of the collection, and confirmation of an organized hematoma on aspiration support a degloving-type mechanism rather than a simple post-contusional hematoma. Although atypical locations of MLL and related degloving injuries have been reported, the lesion observed in the present case occurred at a distinct anatomical plane not typically associated with these injuries [4,6].

The importance of this case lies in the recognition of a possible Morel-Lavallée-like periosteal degloving lesion of the tibia [7]. To the best of our knowledge, no previous report has described a chronic post-traumatic subperiosteal hematoma over the anterior tibia resulting from an MLL-like shearing mechanism. This observation expands the spectrum of closed degloving injuries and suggests that, under appropriate biomechanical circumstances, tissue separation may occur at the fascial-periosteal interface rather than the conventional subcutaneous-fascial plane.

From a diagnostic perspective, bedside musculoskeletal ultrasonography was sufficient to identify the lesion's anatomical plane, characterize its contents, exclude internal vascularity, and demonstrate the absence of bony involvement [5]. Recognition of this unusual injury pattern is clinically relevant, as chronic post-traumatic tibial swellings may otherwise raise concern for infection, neoplasm, vascular lesions, or occult osseous pathology. Awareness of this entity may facilitate accurate diagnosis, appropriate management, and patient reassurance in rehabilitation and musculoskeletal practice.

Conclusions

We report a previously undescribed post-traumatic subperiosteal hematoma of the anterior tibia that appears to have resulted from a Morel-Lavallée-like periosteal degloving mechanism. This novel observation suggests that closed degloving injuries may occur at the fascial-periosteal interface in addition to the classical subcutaneous-fascial plane. Recognition of this new injury pattern expands the spectrum of Morel-Lavallée-like lesions and underscores the value of musculoskeletal ultrasonography in accurately identifying the lesion's anatomical plane and excluding osseous involvement. Future reports of similar Morel-Lavallée-like lesions are needed to facilitate more detailed investigation and improve understanding of their clinical characteristics, diagnosis, and management. Awareness of this entity may facilitate the diagnosis and appropriate management of persistent post-traumatic tibial swellings.