Pain, skin problems, and musculoskeletal concerns such as contracture or early degenerative joint disease are well-known complications of lower limb amputations [1]. All of these situations make it difficult for the patients to walk on a prosthetic leg. A previous study reported that the main barriers which limited the amputees to properly use their prosthetic devices were pain, discomfort, and misfit [2]. In addition, residual limb pain emerged as the most serious problem above all [3]. Inadequate socket fit of the prosthesis is a leading cause of residual limb pain, followed by pressure loads from body parts, close contact with skin, and shearing force from the suspension. Heterotopic ossification or terminal bone growth at the amputation edge can also cause residual limb pain [3]. Suggestions for managing stump pains are prosthetic replacement, medications, physical therapy, pain modality, and surgery [3].

Non-infectious hematoma alone can cause prosthesis fitting failure. Usually, a hematoma is reabsorbed and shrinks over time [4]. However, there have been a few reports of gradually increasing hematoma, which is called chronic expanding hematoma (CEH) [4]. Reid et al. first characterized CEH, which increases in size, appearing later than a month after the initial bleeding [5]. Although some patients may not remember any special traumatic events, the first hemorrhage usually occurs after trauma or surgery [5]. After the first bleeding, the blood itself and its degraded products cause low-grade inflammations and lead to continuous hemorrhage [5]. CEH can occur in various body parts, including calves, thighs, knees, buttocks, abdomen, pelvis, thorax, upper limbs, and breast [6,7]. Among these areas, the thighs and the upper limbs are reported to be the most common sites [7]. However, there have been only few reports of CEH near the amputation stump [6].

Herein, we present a rare case of CEH on the left tibial amputation stump. The CEH repeatedly recurred even after surgical interventions, making it more complicated to manage.

A 59-year-old man who had undergone left transtibial amputation complained of recurrent left stump swelling and pain. He had a medical history of hypertension and diabetes mellitus, and used to be a heavy smoker until a year ago. He suffered from a sizeable diabetic foot ulcer on the right ankle. The ulcer infiltrated into the right distal tibia, suggesting osteomyelitis. He had the right transtibial amputation surgery seven years ago, followed by the left transtibial amputation five years ago for the same reason. After the bilateral transtibial amputations, he was able to walk alone indoors with his prostheses. On the other hand, in the outdoors, his mobility was limited where he was only able to walk independently in a short distance with the use of a cane in his prostheses. He was a K1 ambulator in K-level system.

After that, he received neuroma excision twice due to stump pain and swelling at each stump. However, he complained of terminal residual pain, occasionally described as electric and stabbing, and swelling was often increased only on the left stump. Plain radiography showed spinous bony growth of the stump (Fig. 1). The magnetic resonance imaging of the same area showed hemorrhagic bursa formation below the bony spur at the stump (Fig. 2). The fluid-filled bursa showed several tiny calcifications with rim enhancement. Aspiration of the bursa confirmed non-infectious hematoma formation. The culture result was negative. Three-phase bone scintigraphy revealed no signs of tissue infection or osteomyelitis. With a multidisciplinary approach, we concluded that the bone spurs caused the hemorrhage (Fig. 3). Thus, the patient had a total bursectomy with bone spur grinding. However, several months after the bony stump smoothing surgery, the patient’s stump swelling and pain recurred. The patient underwent another surgery–an open bursectomy, but the hemorrhage returned again only a few months later. Because of these symptoms, he had many difficulties putting on his prosthesis. At those times, even after aspiration and compression, it only took three days for the stumps to be fully swelled with intractable pain. We used computed tomography angiography to find where the blood was leaking. Nevertheless, we could not find the bleeding focus. The pain in the stump could only be temporarily controlled by aspirating the hematoma, then compressing with elastic bandages. When the elastic bandages were removed, the chronic expanding hematoma recurred in only 1 to 2 days. After several repeated cycles of hematoma aspirations and recurrence, we decided to apply long-lasting compression on the stump by changing the socket of the prosthesis to a tighter one, to keep full contact compression. We also instructed him to apply compression bandages on the stump when he was not using the prosthesis. With this conservative management, finally, the patient was able to tolerate walking on prostheses in his ordinary life.

Figure 1. Plain radiograph of left amputation stump. (A) Shortly after the first amputation surgery without appearance of bony spur. (B) Two years after the amputation surgery where formation of bony spur is visible at amputation edge. (C) Immediately after the bony stump smoothing surgery.

Figure 2. T1 weighted magnetic resonance image with contrast enhancement of left amputation stump. Bursitis bellow bony projection of the stump is shown. The fluid filled bursa shows several tiny calcifications with rim enhancement.

Figure 3. Bony spur in the operation field. Black arrow indicates spiky bony spur formation.

CEH can occur in various body parts, including the trunk and limbs [5]. In this case, CEH occurred in the left tibial amputation stump. The lower limb amputation stump is not a well-known area of CEH. CEH usually occurs after trauma or surgery, more than a month after the first bleeding [5]. In this patient, CEH occurred two years after the left transtibial amputation.

Before the stump smoothing surgery, the aspirate resulted in a noninflammatory hematoma, and the location was just below the bony spur. Under the circumstances, we concluded that the bony spur was associated with the hematoma. Takakura et al. [6] reported similar idea, where in their study, sharp bone edges of the stump were trimmed in two CEH patients, and hematoma did not recur. Nevertheless, the CEH recurred on our patient even after multiple soft tissue excisions and bone surgeries. At some point, we began to speculate if the bone spur-grinding procedure itself might have contributed to the development of new CEH. Consequently, we decided to discontinue further surgeries.

CEH formation is caused by incompletely absorbed hematoma. During its necrosis and liquefaction, a cystic granuloma is formed, which is CEH [4]. Pathologically, CEH shows a well-encapsulated mass [4]. The outer wall of the capsule is fibrocollagenous and the inner wall is composed of granulation tissue [4]. A mixture of fresh and old blood is filled inside [6]. Histologically, it is not related to neoplasm [5]. Computed tomography imaging shows a cyst filled with fluid or necrotized inside [4]. In magnetic resonance imaging, the result may vary because the signal intensity of hemoglobin varies over time [4]. Nonetheless, T1 and T2 weighted images display pseudocapsule with low signal intensities in common [8].

For the treatment of CEH, surgical resection or aspiration can be considered [9]. The ideal method is removing the mass, including pseudocapsules [10]. However, if adhesion prevents complete resection, it is sufficient to remove the mass while preserving the attachment portion of the mass [8].

In this patient, the initial bleeding might have been caused by the bony spur of the amputation stump. After the initial hemorrhage, the blood and its degradation products could have caused low-grade inflammation, leading to continuous bleeding, namely CEH. Bony spur grinding surgeries, hematoma removal surgeries, and hematoma aspirations were serially carried out, but CEH kept recurring. Due to CEH, the patient complained of excessive pain, tenderness and swelling of the amputation stump, making it difficult to use prosthesis. Pain was undoubtedly a big problem, and gait disorders caused significant activity limitation. CEH management of amputation stumps is critical since it hinders prosthetic walking gaits.

In this case, the patient had both transtibial amputations. An unrecognizable balance problem may have overloaded his left side stump and could have been a hidden cause of CEH. However, the bleeding recurred even after he stopped wearing prostheses and took bed rest after aspiration. This suggests that once CEH occurs, trauma has no role in aggravation. We could not find any previous study of both lower limb amputations.

To the best of our knowledge, this is the second case report of CEH on the lower extremity stump in single or both limbs [6]. In a previous study by Takakura et al. [6], trimming the bony spur was effective for CEH. However, in our case, surgery alone could not resolve CEH and it repeatedly recurred after surgery. Eventually, only conservative care could manage the pain and swelling. The present case is significant since it documents not only a rare case report, but also a lengthy journey of CEH, from its diagnosis and management failure to the eventual success.