Morel-Lavallée lesion around the knee successfully treated with video-assisted endoscopic débridement: A case report

Abstract

We report a chronic Morel-Lavallée lesion around the knee in a competitive high schooler softball player, successfully treated with video-assisted endoscopic debridement. Endoscopic surgery is a viable option to treat Morel-Lavallée lesions in active patients who seek a rapid return to sport. The potential advantages of an endoscopic treatment would be a faster healing process and an earlier return to motion and function due to a less morbid and more cosmetic surgical approach.

Introduction

Morel-Lavallée lesions (MLLs) are closed traumatic soft tissue degloving injuries characterized by separation of the superficial layers of the skin from the underlying deep fascia due to shearing forces [1]. This leads to venolymphatic leak and concomitant adipose tissue necrosis causing swelling and risk for infection [2]. They present as enlarging, tender lesions with associated pain, tightness, edema, ecchymosis, skin hypermobility, and fluctuance in areas with mobile overlying skin and tough underlying fascia [3]. Patients may also experience decreased sensation of overlying skin. Ultrasound, computed tomography, and magnetic resonance imaging (MRI) can be used as adjuncts to the diagnostic work-up to further characterized the lesion [4]. Shen et al. proposed a simple classification where they divided the lesion into acute and chronic based on the absence or presence of pseudocapsule [5]. Pseudocapsule formation prevent further reabsorption and cause maturation of the lesion into a chronic MLL. MLLs are notoriously challenging to treat. They can be refractory to multiple intervention and can be complicated by recurrence, infection, wound-healing complications which cause poor functional and cosmetic outcomes [3,6,7]. There are currently no guidelines for their management. Compressive therapy and percutaneous drainage are indicated for small (less than 50 cm³), acute lesions without pseudocapsule [8]. For chronic lesions, the use of sclerosing agents such as doxycycline, erythromycin, bleomycin, vancomycin, absolute ethanol, tetracycline, and talc has been successfully applied to MLLs [7,9]. If the overlying skin is viable, open drainage can be achieved through either a single longitudinal incision or several small incisions proximally and distally [3]. Recently, video-assisted endoscopic (VAE) debridement of MLLs has been described to reduce the complications and morbidity associated with open treatment in at-risk patients [10]. Our report describes an MLL in the pre-patellar bursae presented in an active young adult addressed with endoscopic treatment. This case report aims to highlight that debridement of the pre-patellar bursae in cases of MLL is safely achievable with an endoscopic approach.

Case report

The patient was a 17-year-old female with a past medical history significant for anxiety and right knee patellar instability. She was a high school sophomore and enjoyed doing competitive track, softball, and wrestling. She was found to have a closed degloving injury over the anterior aspect of the left knee sustained during wrestling practice. During the initial injury, she was pinned down and ended up sliding on her left kneecap against the floor mattress. The patient noticed immediate swelling on the anterior knee. She consulted a sports physician and physical examination showed significant fluctuance over the anterior left knee extending medial and lateral around the joint (Fig. 1). This area was non-tender to palpation, non-erythematous, and without warmth. There was a slight decreased sensation to light touch over the swelling. A knee MRI showed a partially encapsulated large fluid collection containing fatty globules and debris in the prepatellar space and measuring approximately 9.3 × 2.6 × 7.7 cm more compatible with MLL than bursitis (Fig. 2). There was a T2 hypointense pseudocapsule which had developed around the inferior, superior, and deep margins of the fluid collection. There was no capsule anteriorly. She underwent four months of conservative management including compression sleeve and two percutaneous drainages giving 170 cc and 150 cc of bloody fluid respectively. Because of insufficient progress, she was referred to an orthopaedic surgeon to discuss potential surgical options. Recommendation was to undergo open irrigation and débridement of the MLL. However, the patient was hopeful to participate in the incoming softball season and wished for a faster recovery. Endoscopy-assisted irrigation and débridement was then suggested to have a quicker recuperation and return to sport. On the date of surgery, the lower limb was prepped and draped sterilely, and the pre-patellar bursae was injected with a solution of lidocaine and epinephrine 1:100,000 to decrease the risk of bleeding. Anterolateral and anteromedial portal was performed taking care not to violate the knee joint. A 4.0 smooth shaver was used to clean out the cavity which was inflamed and containing areas of adhesions and septae (Fig. 3). The lining membrane of the lesion was removed endoscopically, taking care not to violate the subcuticular tissue and sent for pathology which had histologic characteristics compatible with pseudocapsule. Compression dressing was applied from the foot to the upper thigh at the end of the procedure. Postoperatively, the patient was weight-bearing as tolerated with the use of crutches. Her knee was immobilized in extension using a knee immobilizer. She was also encouraged to perform leg raise and mobilize her foot up and down to exercise her thigh and leg. The dressing was taken down at the two-week postoperative appointment, and 120 cc of residual bloody fluid was aspirated. Compression dressing was again applied, and she was placed back in her knee immobilizer in extension. At the four-week postoperative follow-up, she again underwent percutaneous drainage of 35 cc of bloody fluid. Five weeks after surgery, the effusion had resolved, and the patient was allowed to open the knee immobilizer three times daily to start flexing the knee. She had to wear a knee sleeve to keep compression on. At the six-week follow-up appointment, the swelling was minimal, and she was freed from the knee immobilizer but counseled to continue wearing the knee sleeve. At the four-month postoperative appointment, her left knee felt much better than before the surgery and did not limit her from any activities. Twelve months after the surgery, at the final follow-up appointment, she was pain free at rest and during activities. She had no more swelling, strength was normal compared to the contralateral side, and range of motion showed full extension and flexion (Fig. 4). She returned to competitive track, softball, and wrestling sports activities and won a state softball championship the same year of her surgery.

Fig. 1.

Comparison between the right and left knees.

Legends: Observe the increased volume and effusion in the prepatellar area of the left knee.

Fig. 2.

Preoperative MRI images of the left knee.

Legends: MRI reveals an extensive fluid collection on the anterior aspect of the knee, extra-articular and primarily concentrated in the prepatellar bursa. The image is compatible with an internal degloving injury with effusion (E), fatty lobules and debris (F) namely a Morel- Lavallée injury in the prepatellar space measuring approximately 9.3 × 2.6 × 7.7 cm. A pseudocapsule (P) is also visible.

Fig. 3.

Intraoperative endoscopic view of the pre-patellar bursae and its communication to the anterolateral recess of the distal aspect of the thigh.

Legends: There is significant hyperemia (H) and debris (D) in the area with multiple septae (S) and a pseudocapsule (P) which are compatible with a Morel-Lavallée lesion.

Fig. 4.

Comparison of the knees twelve months after surgery.

Legends: The patient has a symmetrical appearance of the knees. She has a normal function, a normal range of knee motion, and an intact extensor mechanism.

Discussion

The traditional treatment of an acute MLL that failed conservative management or a chronic lesion with pseudocapsule is open irrigation and debridement [3]. However, this approach carries risks such as recurrence, infection, skin necrosis, contour deformity, and functional deficit [8]. Recent reports described the use of endoscopy to reduce morbidities associated with open surgery. In 2012, Gennip et al. were the first to show endoscopic debridement to be effective in a 15-year-old boy with an acute MLL [11]. In 2016, Kim described successful treatment in a 14-year-old with MLL of the leg using endoscopy and sclerotherapy with doxycycline [12]. Later, Koc et al. reported successful treatment with endoscopic débridement and fibrin glue of a MLL of the knee in a 33-year-old professional soccer player [13]. Liu et al. described a case series of 8 endoscopic débridement surgeries of MLL combined with percutaneous cutaneo-fascial suture [14]. All patients successfully healed from their lesion and no one encountered postoperative complications. In 2021, Kage et al. wrote on a 51-year-old diabetic male with a MLL of the thigh successfully treated with endoscopy and negative pressure wound therapy [10]. Lately, Chan et al. published a technique surgery paper describing the use of endoscopy to treat chronic MLLs around the knee [15]. Potential advantages of the VAE procedure over standard open surgical approaches were less soft tissue trauma, better cosmetic results, fewer wound complications, and less risk of nerve injury.

Our case report describes a refractory chronic MLL around the knee confirmed by clinical exam, MRI, and postoperative pathology. Its treatment was safely achieved with endoscopic technique which adds up to the current literature on the topic. It also showed that endoscopic management could successfully be used in high-demanding patients who need a rapid return to sport. The two postoperative aspirations following surgical intervention in our case point out that endoscopic procedure should be combined with an adjuvant procedure such as a sclerosing agent injection, drain placement, cutaneo-fascial suture, or negative wound pressure therapy to reduce the likelihood of fluid accumulation in the cavity.

In conclusion, VAE debridement allows for direct visualization and excision of the pseudocapsule in MLL. We strongly recommend its use for patients who seek expedited recovery such as young athletes. This method at least matches the primary goal of surgical debridement with smaller incisions, improved patient comfort, and faster recovery. The additional use of adjuvant therapy should be considered to aim for a more expedited adhesion of the internal cavity layers.

CRediT authorship contribution statement

Pierre-Emmanuel Schwab: Writing – review & editing, Writing – original draft. João Bourbon: Writing – review & editing. Jay T. Bridgeman: Supervision. Samuel Brown: Writing – review & editing. Mauricio Kfuri: Writing - review & editing, Supervision.

Declaration of competing interest

The authors have no conflict of interest to disclose.