Gait Acquisition with a Quadrilateral Socket after Ultra-short Transfemoral Amputation because of Staphylococcal Toxic Shock Syndrome

ABSTRACT

Background: Streptococcal toxic shock syndrome (STSS) is a notifiable disease under Japan’s Infectious Disease Control Law and has become a pandemic following COVID-19. STSS often leads to necrotizing fasciitis, with a mortality rate exceeding 30%. Even in surviving patients, limb amputations are common.

Case: A 39-year-old woman developed STSS. She underwent 18 surgeries and vacuum-assisted closure therapy, which resulted in ultra-short right transfemoral amputation. With a strong desire to walk again, she began fitting for a provisional prosthesis 3 months post-amputation. Given the preserved hip muscle strength, an ultra-short transfemoral prosthesis was selected over a hip disarticulation prosthesis. The key components included a plug-in quadrilateral socket, a belt used to suspend the transfemoral prosthesis, a hydraulic knee joint, and an energy-storing foot. She regained walking ability using crutches. To address pain and skin issues in the stump load-bearing area, compression and adhesion were improved using thick fabric spats. Muscle mass, including that of the paraspinal muscles, was maintained during follow-up evaluations using computed tomography, dual-energy X-ray absorptiometry, and bioelectrical impedance analysis. The phantom limb pain in the right leg diminished with medication and prosthetic training. Her quality-of-life scores measured using the 36-item Short Form Questionnaire and the Prosthesis Evaluation Questionnaire also showed improvement. She was discharged home 5 months post-amputation.

Discussion: This case highlights the importance of high motivation, multidisciplinary collaboration, preservation of the trunk muscle reserve from pre-illness exercise habits, and early trunk rehabilitation to achieve successful gait acquisition with a customized transfemoral prosthesis.

INTRODUCTION

Streptococcal toxic shock syndrome (STSS) is a notifiable disease under Japan’s Infectious Disease Control Law, defined as “a condition caused by beta-hemolytic streptococci, characterized by sudden onset and rapid progression to septic shock”.^1,2,3) STSS predominantly affects middle-aged and older individuals aged over 60 years, with a mortality rate exceeding 30%.^2,3,4) No sex differences in the onset or prognosis are observed.⁵⁾ Although some cases involve underlying conditions such as malignancies and diabetes that may lead to immunosuppression, 30% of cases have been reported to have no significant medical history.⁶⁾

We observed an STSS pandemic following the COVID-19 pandemic in Japan.⁷⁾ The primary factors influencing annual epidemiological shifts in infectious diseases can be broadly categorized as follows: 1) social environment change; 2) host-related changes; and 3) changes in pathogens.⁸⁾ The increase in STSS cases in Japan from January 2024 can be attributed to the resurgence of social mobility and face-to-face interactions following a decline during the COVID-19 pandemic. Host-related changes include reduced opportunities for acquiring and maintaining immunity against various pathogens during the pandemic. Currently, the prevalent strain of Streptococcus is the emm1 type with genetic mutations, which has decreased in frequency during the COVID-19 pandemic.⁷⁾ This strain produces complement-inhibiting substances under anaerobic conditions that other Group A Streptococcus (GAS) strains typically do not possess, making it more likely to cause severe complications.⁹⁾ It often causes necrotizing fasciitis with a mortality rate exceeding 30%. Even when survival is achieved, limb amputations are frequently necessary.^4,6)

Herein, we present the case of a 39-year-old woman with no underlying conditions who developed STSS. She underwent 18 surgeries and vacuum-assisted closure therapy, which resulted in ultra-short right transfemoral amputation. With a strong motivation to regain walking ability and preserve hip muscle strength, she was able to achieve gait using a customized transfemoral prosthesis. In this case, successful gait acquisition was attributed to sustained patient motivation, multidisciplinary collaboration including nutritional support, preservation of trunk muscle reserves from pre-illness exercise habits, and early trunk rehabilitation.

CASE

Recent Patient History

On the first day of winter, a 39-year-old woman experienced swelling and pain in her right lower leg. On the second day, she had a fever of 40 °C, and, by the third day, she developed shortness of breath and was transported to a city hospital. Necrosis was observed on the skin of her right thigh, and emergency skin incision and debridement were performed because of circulatory failure. On the fourth day, she underwent amputation of the right thigh. Subsequently, vacuum-assisted closure (VAC) therapy was performed in 18 additional surgeries, and the wound was completely closed on the 60th day. GAS bacteria were detected in the wounds and the patient was diagnosed with STSS.

Rehabilitation therapy was initiated in the intensive-care unit (ICU). By the 15th day, the patient started training for bed-to-chair transfers, and, by the 22nd day, she began standing exercises. From the 43rd day, she maneuvered in a wheelchair and walked with parallel-bar support. Lightly assisted walking training with crutches began on the 58th day, and, by the 75th day, she was able to walk outdoors with crutches. The patient was transferred to our hospital on the 77th day to create a prosthesis for her right lower limb.

Pain Perception

Phantom limb pain developed on the seventh day. The pain varied, including pricking, tingling, and squeezing sensations, with the toes being most affected. During treatment, pain management proved difficult, requiring intravenous fentanyl. However, with the use of oral medications (amitriptyline 10 mg, tramadol 100 mg, acetaminophen 2000 mg, and pregabalin 150mg), by the time of her transfer to our hospital, the pain had expanded to the thigh area but was reduced to about 3/10 on the Numerical Rating Scale (NRS).

Patient Background

The patient was active as a handball player during her school years. At the age of 12 years, she fractured her right leg in a fall on a set of stairs. She ruptured ligaments in her right leg during handball practice at middle school at 14 years of age, was treated for community-acquired pneumonia at 15 years of age, and had appendicitis at age 17 years. At 36 years of age, she underwent surgery for cervical cancer. There was no report of similar medical conditions among family members.

The patient’s general lifestyle was based on work and the care of her children. At the place of her employment, office facilities used by the patient were located on the second floor of an office building (no elevator) that was a few minutes’ drive from home. Typically, she commuted to the office by car and dropped three children to school and picked them up. She was a university graduate. At home, the patient lived in a detached house with a gravel path in front of the entrance. Access to the house required the patient to traverse a 15-cm step at the front gate and another at the front door, but the interior of the house was barrier-free. For recreation, the patient enjoyed supporting her eldest son’s youth baseball team.

Symptoms and Assessment at Admission

The patient was clearly conscious, showed good communication, and showed no signs of depression. The following data were recorded: blood pressure, 110/80 mmHg; pulse, 80 beats/min; height, 158.9 cm; weight, 49.5 kg; body mass index (BMI), 19.58 kg/m². There was no problem with the cranial nerves, chest, or abdomen. The patient could stand independently on her left leg and could stand on her tiptoes and heels of the left leg. Her hand grip strength was 22 kg bilaterally. Right hip strength (manual muscle testing; MMT) and range of motion (ROM) were preserved (MMT 5; ROM: flexion 120°, extension 30°, abduction 45°, adduction 20°). Sensory disturbance at the distal end of the stump was rated 3/10. Her Barthel Index was 85. Blood tests revealed no abnormalities suggestive of immunosuppression, such as decreased white blood cells or immunoglobulins.

After the fifth day of illness (Fig. 1A) and subsequently, the stump continued to show infection and required repeated debridement. As a result, by the 60th day, the right femur was amputated just below the lesser trochanter, 36 mm distal to the greater trochanter (Fig. 1B). By the 81st day (Fig. 1C), the skin was soft with partial scab formation, but no redness or inflammation was observed.

Fig. 1.

Condition of the amputation stump (A–C), photographs of the transfemoral prosthesis (D, E), and photographs of the patient’s walking ability with crutches on day 286 (F).

Clinical Course

The patient had a strong desire to regain walking ability and began the process of creating a temporary prosthesis 2 months after the amputation. Various options were considered, including Canadian-style, diagonal, and single-side pelvic socket prostheses, as well as suspension methods such as pelvic bands, waist belts, and total elastic suspension belts. However, because the ROM and strength of the hip joint were preserved, a hip prosthesis with a hip joint was not adopted. Considering her employment and her role as a mother, a hip joint may have been difficult to manage. Instead, we selected a transfemoral prosthesis for ultra-short stumps. Because of the ultra-short amputation stump, a plug-in-type prosthesis with silicone liner was unsuitable, and the irregular shape of the stump precluded a suction-type prosthesis. Instead, we used a simpler plug-in quadrilateral socket with a suspension belt to supplement the suspension function (Fig. 1D,E), as opposed to using a belt or strap system. The main components were a plug-in quadrilateral socket, a hydraulically controlled knee joint, and an energy-storing Solid Ankle Cushion Heel foot. Throughout the creation process, the patient was repeatedly allowed home visits and trained on tasks such as household chores and navigating slopes around her home, including taking her children to daycare.

Rehabilitation focused on lower limb and truncal exercises, including crunches, draw-ins, back cross extension, bridges, and side bridge, as well as static standing on a balance mat and reaching movements on a balance mat. Walking was performed using mirrors and parallel bars to ensure correct movement. Physical assessments of the patient over the course of her treatment and rehabilitation are shown in Table 1. The Short Physical Performance Battery (SPPB)^10,11) 10,11 score improved from 6 on day 80 to 9 on day 150. In the balance test, the patient could stand on one leg for more than 10 s at 2 months (1 point). At 5 months, when the prosthesis was introduced, she was given a full score in the balance test (4 points). Walking speed (4-m walk test) improved from 5.3/4.6 s at 5 months to 4.75/4.37 s at 6 months, but her time to rise from a chair was slightly longer (Table 1).

Table 1. SPPB assessment during the course of disease and rehabilitation

Assessment	Time after amputation
	2 months	5 months	6 months
Balance test (points)	1	4	4
Gait evaluation (points)	3	4	4
Number of steps	4/4	8/7	7/7
4-m walk test (s)	4.9/4.9	5.3/4.6	4.75/4.37
Stand-up test (points)	2	1	1
Stand-up time (s)	15	18	19
Total score (points)	6	9	9

Computed tomography (CT) of the trunk showed that the surgery had caused atrophy in the gluteus maximus around the stump, but the paraspinal muscles were maintained throughout hospitalization (Fig. 2). Although accurate assessment was difficult because of the amputated limb, muscle mass evaluation using dual energy X-ray absorptiometry (DEXA) and Bioelectrical Impedance Analysis (BIA) showed improvement during the 2-month hospitalization (Table 2).

Fig. 2.

Comparison of truncal CT findings between day 4 (A, B) and day 150 (C, D). The gluteal muscles around the amputation site (A, C) showed atrophy because of the surgical procedure, whereas the paraspinal muscles (B, D) were preserved throughout the hospital stay.

Table 2. Body mass and mineral analysis by DEXA and BIA

Analysis	Time after amputation
	3 months	5 months
DEXA
Lean mass and bone mineral content (g)
Left arm	2234	2219
Right arm	2000	2102
Trunk	19998	21049
Left leg	6832	6306
Right leg	967	528
Appendicular lean mass index (kg/m2)	4.48	4.35
BIA
Body weight (kg)	49.5	50.1
Height (cm)	158.9	158.9
BMI (kg/m2)	19.6	19.8
Muscle weight (kg)	45.7	46.2
Body fat mass (kg)	1.5	1.5
Segmental lean analysis (kg)
Right arm	1.02	1.32
Left arm	1.17	1.31
Trunk	12.5	13.8
Right leg	31.01 (error)	46.75 (error)
Left leg	6.32	6.65
Skeletal muscle index (kg/m2)	15.7	22.2
Whole body phase angle (degrees)	4.5	5.2

On day 147, the patient achieved independent walking with crutches using a plug-in quadrilateral socket, a suspension belt, a hydraulically controlled knee joint (LAPOC M0790 Motion Control Knee; IMASEN ENGINEERING CORPORATION, Kagamigahara, Japan), and a foot prosthesis (1C30 Trias; Ottobock SE & Co. KGaA, Duderstadt, Germany). Thick spats were used in the load-bearing area of the stump to provide pressure protection, improve adhesion, and prevent skin erosion. From day 160, she could walk with two crutches (Fig. 1F; photographs on day 286). For convenience, the patient utilized the turntable function when getting into a car or putting on her shoes. She wore the prosthesis for several hours each day and was able to resume activities such as picking up and dropping off her children and returning to work in her second-floor office.

The phantom limb pain in her right lower limb was alleviated by medication and prosthetic walking training. Oral medication was reduced to 25 mg of tramadol. The overall quality of life (QOL) assessment using the 36-item Short Form Questionnaire (SF-36)^12,13) showed significant improvement, with scores increasing in physical functioning from 5 to 50, bodily pain from 0 to 84, and social functioning from 0 to 37.5, among other categories (Table 3). The Prosthesis Evaluation Questionnaire (PEQ)¹⁴⁾ also indicated an improvement in QOL, with scores increasing from 22 to 66 (Table 4). In relation to phantom limb pain, improvements were seen in the Brief Pain Inventory (BPI)¹⁵⁾ from 7 to 4, and the Pain Catastrophizing Scale (PCS)¹⁶⁾ from 12 to 6 (Table 5). The patient was discharged home 5 months post-amputation. At discharge, her K-level was K2.¹⁷⁾ By the sixth month, when she had adapted to home life, further improvements in SF-36 scores were confirmed (Table 3).

Table 3. QOL assessment scores based on SF-36

Component	Time after amputation
	1 month	5 months	6 months
Physical functioning	5.3	29.8	38
Role physical	10.5	22	24.9
Bodily pain	15.7	53.8	53.8
General health	27.6	51.9	46.7
Vitality	25.5	43.8	55.9
Social functioning	12.8	29.6	46.4
Role emotional	12.3	30.8	49.4
Mental health	36.8	47	54.5

SF-36 license from Qualitest iHope International.

Table 4. QOL assessment scores based on PEQ

Component	Time after amputation
	3 months	5 months
Perceived response
Severity of pain	65/100	86/100
Degree of difficulty	42/100	92/100
Well-being
Satisfaction with course of events	11/100	21/100
QOL	22/100	66/100

Table 5. QOL assessment based on pain rating scales

Pain assessment	Time after amputation
	2 months	5 months
Wound pain
NRS (0–10)	1	1
Phantom pain
Visual analog scale (0–10)	4	2
BPI (0–10)	7	4
PCS (0–52)	12	6

During her hospital stay, the patient experienced menstrual irregularities and hair loss. Blood tests revealed zinc deficiency with a blood level of 57.4 µg/dL. Considering this correlation, oral zinc supplementation at 10 mg was administered, which was later increased to 34 mg, resulting in an improved blood level of 82.6 µg/dL. In addition, her magnesium level was low, prompting a 46-mg supplementation, which normalized her magnesium levels. Her estimated daily caloric requirement was 1767.8 kcal based on an activity factor of 1.3 and a stress factor of 1.1. Given that the patient met one phenotypic and one etiologic criterion of the Global Leadership Initiative on Malnutrition (GLIM) criteria, a diagnosis of malnutrition was confirmed, and she received nutritional guidance accordingly.

Ethics Approval

The Institutional Review Board and Ethics Committee of Tohoku University approved the case report (approval number 36622). The patient provided written informed consent for publication of the report.

DISCUSSION

Contributors to Successful Ambulation

High-level amputation, older age, and the presence of complications are generally associated with poor functional outcomes in lower limb amputees.^{18,19,20,21,22)} In predicting the prognosis of gait acquisition in lower limb amputees, balance tests and cardiopulmonary function measurements have been reported as useful.^23,24,25) In the present case, the following seven factors contributed to successful ambulation:

• 1. Early initiation of rehabilitation: rehabilitation therapy commenced early during hospitalization, effectively minimizing any ICU-acquired weakness.²⁶⁾ It is pointed out that early rehabilitation is important even in cases of amputation associated with ischemia.²⁷⁾

• 2. High motivation for ambulation: the patient’s strong motivation for ambulation, which is necessary for childcare and work, plays a crucial role. In cases of limb loss, maintaining independence and engagement in community and social life is also considered important, as well as having the motivation to achieve these goals.²⁸⁾

• 3. Sustained motivation: the patient maintained her motivation and collaborated with a multidisciplinary team, including prosthetists, to optimize prosthetic fittings. In reports of elderly amputees, one of the factors enabling long-distance walking is whether the patient has the motivation to walk.²⁹⁾

• 4. Core strength enhancement: pre-existing experience in sports emphasizing core and limb strength might facilitate early focus on core rehabilitation and preserve hip muscle strength during prosthetic fitting. To our knowledge, previous reports^23,25,30) have not mentioned the history of sports participation prior to amputation, and this is a point that requires further investigation in the future.

• 5. Optimal prosthetic selection: opting for a thigh prosthesis enabled the utilization of proximal leg muscles during walking and had the advantage of reduced weight when compared with hip prostheses.^23,25,30)

• 6. Progressive muscle mass increase: despite challenges in precise assessment because of amputation, DEXA and BIA assessments showed increased muscle mass over time, indicating effective rehabilitation. Nutritional support also enhanced the muscle mass increase. As part of the rehabilitation for lower limb amputees, increased nutritional guidance is recommended.³¹⁾

• 7. Preservation of paraspinal muscles: preservation of the paraspinal muscles potentially aids in predicting ambulation prognosis,^32,33) suggesting its future utility in analysis.

We consider that these combined factors contributed to successful ambulation. Continued analysis and optimization of rehabilitation strategies based on further cases will be crucial for the improvement of outcomes.

Improvement of Phantom Limb Pain after Prosthetic Limb Creation

In this case, over the course of 2 months during prosthetic limb fabrication, intervention through exercise therapy enabled a reduction in analgesic medication. Furthermore, the nature of phantom limb pain evolved during the prosthetic limb creation process, suggesting that relearning ambulation with the prosthetic limb may have contributed to the remodeling of neural circuits and alleviation of phantom pain.³⁴⁾ Reports indicate that sensory feedback restoration in leg amputees improves walking speed, metabolic efficiency, and phantom pain.^35,36) Therefore, it is plausible that the prosthetic limb creation played a role in the improvement of phantom pain in this case.

Nutritional Disorders in Amputee Cases

Zinc has an absorption rate of 20%–40% through oral intake and is primarily absorbed from the duodenum to the upper jejunum.³⁷⁾ The human body typically contains 1.5–3 g of zinc, with 60% of this amount held in muscle.³⁸⁾ Normal values vary by report, but studies have shown significantly lower levels in individuals with sarcopenia aged 65 years and over (57.1 µg/dL) when compared with controls (62.9 µg/dL).³⁹⁾ In the present case, clinical significance was inferred from the observed hair loss and irregular menstruation, indicating meaningful hypozincemia, for which oral supplementation was administered. Amputees often exhibit reduced muscle mass, potentially leading to decreased zinc reserves and increased susceptibility to hypozincemia. Attention to other trace elements such as magnesium is also crucial.

Estimation of Muscle Mass in Amputees

In the present case, increased activity during walking training required vigilance for malnutrition, and body weight was maintained throughout the course of rehabilitation. Adequate calorie supplementation to match the increased level of physical activity was important. Despite attempts to assess muscle mass via DEXA and BIA, obtaining accurate values is challenging in cases impacted by limb amputation, highlighting the need for more precise indicators that reflect the effects of training.

ACKNOWLEDGMENTS

We thank the attending physicians for their assistance in this case. We deeply appreciate the assistance and expertise of Mr. Tatsuro Umeoka, Ms. Saori Kawanishi, and Ms. Kotone Okuno from Sasaki Prosthetics in adjusting the prosthetic device. We thank Editage (www.editage.jp) for English language editing of a draft version of this manuscript. This study was supported by a Grant-in-Aid for Research on Rare and Intractable Diseases (23FC1014) from the Ministry of Health, Labour, and Welfare of Japan.

CONFLICTS OF INTEREST

The authors declare no conflict of interest.

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