Chronic Diabetic Foot Osteomyelitis Presented as a Sausage Toe Treated With Internal Pedal Amputation: A Small Case Series

ABSTRACT

The treatment of a chronic diabetic foot osteomyelitis (DFO) is challenging and often necessitates a surgical intervention. When the soft tissues are preserved from infection, an internal pedal amputation (IPA) defined as the excision of the totality of at least one bone could yield excellent results in terms of infection control and limb preservation. The diabetic sausage toe is an under‐researched form of DFO. Therefore, the aim of this preliminary study is to report the outcomes of IPA for the treatment of chronic diabetic sausage toes. This is a case‐series of six patients presenting as chronic diabetic DFO of the toes in the form of sausage toe. Five patients presented with an open ulcer and one with a healed wound. All patients were treated with IPA. Infection healing, x‐rays and MRI findings, microbiology and pathology results, postoperative complications and patient satisfaction were recorded. Four out of the six cases (66.7%) presented clear radiological signs of chronic OM. All cases showed signs of OM on MRI. A bacterial micro‐organism was found in 5 out of the 6 cases (83.3%) and all specimens showed signs of chronic inflammation on pathology. No infection recurrence was noted at the last follow‐up. All postoperative wounds healed within 6 weeks. All patients were extremely satisfied with the surgical result. For chronic diabetic toe osteomyelitis in the form of a sausage toe, the toe‐preserving technique of internal pedal amputation has the potential to control the infection while conserving an aesthetic and functional toe.

Level of Evidence

IV.

Summary.

• Chronic diabetic foot osteomyleitis is challenging. Not infrequently, it could present in the form of a sausage toe. This case‐series showed excellent results when treating this infection with internal pedal amputation, by removing the totality of the infected bone and preserving the surrounding soft tissues.

1. Introduction

Diabetic foot infection (DFI), and in particular diabetic foot osteomyelitis (DFO) is a challenging condition that could lead to serious complications. Most diabetic foot ulcers (DFU) and DFI are observed in the forefoot with a frequency ranging from 60% to 90% [1]. Forefoot infections could lead to lower extremity amputation (LEA) and premature mortality in people with diabetes [2]. Among the many presentations of DFO is the sausage toe deformity. Rarely researched [3, 4, 5], a sausage toe could be induced by an acute or chronic DFO. Usually, acute and non‐treated chronic DFO could respond well to antibiotics, yet with high failure rates ending with amputation [6].

In the case of a sausage toe, the osteomyelitis is usually associated with a moderate infected ulceration and relatively preserved soft tissues, categorised as University of Texas Stage 3/Grade B or Wagner Grade 3 or Infectious Diseases Society of America (IDSA) Grade 3. In some chronic cases, the ulcer is healed with persistence of the sausage deformity. Chronic forefoot DFO previously managed with antibiotics are usually treated with either conservative surgery or digital amputations [7, 8, 9, 10, 11].

Conservative surgery of a chronic DFO is often based on the resection of the infected bone associated or not with soft tissue procedures such as Achilles lengthening, selective plantar fascia release or percutaneous toe flexor tenotomy [12]. In some instances, the totality of the bone, phalanx or metatarsus, is infected and a total resection is required. This old technique is called internal pedal amputation (IPA) where one or more phalanges, metatarsals or midfoot bones are removed while preserving the enveloping soft tissues [13, 14]. When indicated, the results were found to be excellent in terms of infection and wound healing with few postoperative complications [15].

In this study, we report the outcome of the IPA technique for the treatment of chronic osteomyelitis presented as a chronic sausage toe treated previously with antibiotics but with no success.

2. Methods

2.1. Study Design

This is a retrospective case series of continuous patients treated in our institution. We retrieved the electronic charts and radiological images of patients diagnosed with chronic DFO who presented with a sausage toe deformity and were treated with internal pedal amputation. Approval from the Institutional Ethical Board of our university hospital was secured prior to the study. Written consent forms were obtained from patients who agreed to publish images of their toe cases. This study followed the guidelines of the Joanna Briggs Institute Checklist for case series studies [16].

2.2. Patient Selection

Only patients with DFO limited to the toes at or distal to the metatarsophalangeal joint were included. Patients who had active or healed wounds were also included. Only those who were treated with at least one total phalangectomy were candidates for inclusion. Cases treated with only a partial phalangeal resection were discarded; however, a partial bone resection associated with a total phalangectomy (or more) was accepted. Acute cases of sausage toes were not accepted, and DFO with plantar neuropathic conditions beneath metatarsal heads was also excluded. All patients received a peripheral arterial evaluation from the vascular team prior to surgery, including an Ultrasound Doppler. All patients had x‐rays and MRI documentation. A minimum period of 12 months of follow‐up was required for inclusion.

2.3. Osteomyelitis Diagnosis

A probe‐to‐bone test was conducted for all open wounds. X‐rays and MRI were done for all patients in search of OM signs. All bone specimens were sent to pathology exam in search of chronic inflammation suggestive of OM.

2.4. Outcome Definition

Infection recurrence was defined as the primary outcome. Wound complications and patient satisfaction were set as secondary outcomes. Patient satisfaction, based on gait and aesthetics, was rated based on a Likert scale that ranged from 1 (extremely dissatisfied) to 5 (extremely satisfied).

2.5. Surgical Technique

Internal pedal amputation of a toe was defined as the total excision of at least one phalanx of the involved digit. In cases where an open wound was present, the ulcer was first excised and the wound was extended proximally and distally to perform the IPA. In cases with a healed wound, the scar was excised before proceeding with the same steps. Bone specimens were cut in half and sent to microbiology and pathology labs. Suspicious soft tissues were excised and sent to microbiological exam.

3. Results

3.1. Sample Data

Six patients (3 males and 3 females) were included with a mean age of 70.8 ± 8.1 years. The mean DFO duration was 16.1 ± 3.1 weeks. The mean HbA1c was 7.05 ± 0.6. The mean CRP level was 18.2 ± 23.3 mg/dL. The mean creatinine level was 0.91 ± 0.25 mg/dL. The mean follow‐up period was 16.1 ± 3.1 months.

All patients showed the complete presentation of the sausage toe: swelling, erythema, and non‐pitting edema, but with varying degrees of intensity. Five patients presented with an open ulcer and one with a healed wound. All patients with an open wound had a positive probe‐to‐bone test and were classified as University of Texas Stage 3/Grade B. Details of the involved toes and wound site are shown in Table 1. In all cases, the vascular status was deemed satisfactory and no revascularisation prior to surgery was performed.

TABLE 1.

Characteristic of the patients.

Case number	Sex	Age	HbA1c	Toe involved	Site of wound	DFO duration (weeks)	Removed phalanges
1.	Male	64	6.9	Right 1st toe	Lateral	12	Distal phalanx
2.	Male	62	7.2	Right 5th toe	Dorsolateral	16	Middle phalanx
3.	Female	71	6.9	Right 1st toe	Lateral	21	Proximal phalanx + base of distal phalanx
4.	Male	67	8.2	Left 1st toe	Lateral	17.5	Proximal and distal
5.	Female	81	6.3	Left 5th toe	Dorsal	14	Proximal and middle
6.	Female	80	6.8	Right 5th toe	Dorsolateral	16	Proximal phalanx

3.2. Imagery Findings

Four out of the six cases (66.7%) presented clear radiological signs of chronic OM, including cortical irregularity, radiolucency, sclerosis, sequestrum, or fragmentation. All cases showed signs of OM on MRI, with post‐contrast enhancement of the bone marrow.

3.3. Micro‐Organism and Pathology Results

A bacterial micro‐organism was found in 5 out of the 6 cases (83.3%) and all specimens showed signs of chronic inflammation on pathology.

3.4. Outcomes

The location of the removed phalanges in the six sausage toes is shown in Table 1. No infection recurrence was noted at the last follow‐up. Wound closure was achieved with tension‐free sutures, and wound healing was observed in all cases. All postoperative wounds but one healed within 4 weeks. We encountered one case of wound healing delay where healing was completed at 6.5 weeks.

In terms of subjective experience, every patient was extremely satisfied with the surgical result, scoring 5/5 on the Likert scale. In all cases, gait was not affected by the surgery.

3.5. Clinical Cases

3.5.1. Case 1

A 71‐year‐old female patient presented with a sausage toe of the right hallux. The deformity had been present for 21 weeks, and the lateral wound had healed 3 months prior to presentation. During the period when the wound was open, the patient received multiple courses of antibiotics with a history of negative microbiology culture. No antibiotics were given after wound healing. The radiographs showed fragmentation and sclerosis of the proximal phalanx and the base of the distal phalanx (Figure 1a). MRI with gadolinium demonstrated signs of osteomyelitis at the same radiological locations (Figure 1b). The patient agreed to the surgical treatment of internal toe amputation. Under nerve block, the healed ulcer was excised with a proximal and distal extension of the wound (Figure 1c). The proximal and distal phalanges were exposed; we proceeded with P1 phalangectomy, then with the resection of the distal half of P2, 5 mm distal to the MRI OM sign (Figure 1d). Skin closure was done on a loose drain (Figure 1e) and a postoperative x‐ray was done (Figure 1f). The bone specimens showed chronic inflammation highly suggestive of OM, while the soft tissues culture revealed staphylococcus coagulase negative. After culture results, the broad spectrum antibiotics were changed according to the antibiogram. Figure 1g shows the aspect of the wound 6 weeks post‐operatively.

FIGURE 1.

Sausage hallux toe.

3.5.2. Case 2

An 80‐year‐old female presented with a history of a sausage toe of the right 5th finger over a period of 16 weeks. She was treated initially with one course of antibiotics for 6 weeks, then treatment was stopped. Afterwards, a topical treatment was used as an attempt to heal her dorsolateral wound over the middle phalanx area, with no success (Figure 2a). X‐rays show fragmentation of the head of the proximal phalanx (Figure 2b) and MRI shows OM signs of the proximal phalanx (Figure 2c). A proximal phalangectomy was decided. The ulcer was excised and P1 exposed, then resected in totality (Figure 2d–f). The bone specimen was divided into two pieces, one for microbiology and one for pathology. The surrounding infected soft tissues were sent to microbiology. Staphylococcus aureus was detected in cultures and chronic OM on pathological exam. Figure 2g showed the postoperative x‐ray and Figure 2h shows the postoperative wound at 4 weeks.

FIGURE 2.

Sausage 5th toe.

4. Discussion

The occurrence of a DFU, particularly when complicated with a DFO, is considered a pivotal event in the diabetic population [17]. In approximately 60% of cases, an infection could complicate a DFU, which could lead to amputation and death [18]. DFO presentation is usually classified into four categories: infected diabetic foot attack, osteomyelitis superimposed on Charcot's neuroarthropathy, infected DFU, and the sausage toe deformity. The sausage toe seems to be a rare clinical presentation that has been poorly investigated. However, a recent study by our team revealed that this entity is relatively frequent in diabetic toe infection, with a prevalence of 30% and where acute cases were more frequent than chronic ones (62.5% vs. 37.5%) [19]. The few reports exploring diabetic sausage toes concluded that this presentation is highly suggestive of osteomyelitis [3, 4, 5]. We have confirmed this statement when we demonstrated that a sausage toe is associated with osteomyelitis in 87.5%, while a septic arthritis was found in the remaining cases [19].

Conservative treatment based on antibiotics and topical dressings is usually long, and infection recurrence is frequent when treating DFO. While this protocol could be efficacious in acute DFO cases [19, 20], the outcome is less favourable in cases of chronic DFO [21]. A high percentage of infection recurrence following a long period of antibiotics is reported in cases of chronic osteomyelitis [22]. Surgical excision of infected bone and soft tissues, named conservative surgery, is required when medical management fails. It has been demonstrated that such surgery could yield good to excellent outcomes in diabetic toe ulcers complicated with osteomyelitis [7, 8, 9, 11].

One of the rare studies conducted on the management of diabetic sausage toes reported that 62.5% (10 patients) of their 16 patients required a surgical intervention, half of them needing an amputation [23]. These authors did not record the type of the sausage toe, whether acute or chronic. In our series, none required secondary amputation during follow‐up.

Internal pedal amputation is one category of conservative surgery and has proven to be efficient when soft tissues were preserved with a weighted healing rate of 87.7% and a low rate of complications [15]. Our small series showed that an IPA applied to the toes, namely internal toe amputation, was successful in all six cases of chronic resistant diabetic sausage toes. Our surgical decision on how many phalangeal bones were to be removed was directed initially by the site of the wound and based quite exclusively on MRI findings. Following the void created by removing the infected bone, skin closure could be achieved with no tension.

In addition to the aesthetic results where patients expressed deep gratitude for preserving the affected toes, the functionality seems to be preserved. None of our patients observed significant change in their gait.

We acknowledge the inherent limitations of a small sample size and the lack of comparison with other methods of treatment. Nevertheless, this small case‐series could lay down the basis for future research in evaluating the IPA technique for diabetic OM in the form of sausage toe. In this frail population prone to high morbidity and mortality, we believe that every avenue that could lessen amputation and complication frequencies is worth evaluation.

5. Conclusions

With a proper indication, patients with a chronic diabetic toe osteomyelitis in the form of a sausage toe could benefit from internal pedal amputation. This toe‐preserving technique could have the potential to control the infection while conserving an aesthetic and functional toe.

Ethics Statement

Ethics obtained from the Institutional Review Board (LAUMCRH.KY2.25/Nov/2020).

Consent

Informed consent statements were obtained from the patients.

Conflicts of Interest

The authors declare no conflicts of interest.

Yammine K., Mouawad J., Jamaleddine Y., and Assi C., “Chronic Diabetic Foot Osteomyelitis Presented as a Sausage Toe Treated With Internal Pedal Amputation: A Small Case Series,” International Wound Journal 22, no. 8 (2025): e70736, 10.1111/iwj.70736.

Data Availability Statement

The authors have nothing to report.