Isolated Subtalar Dislocations: Insights from a Case Study and Literature Review

Abstract

Background:

Isolated subtalar joint dislocations without associated fractures are rare in the medical literature. They occur when the talus bone remains in place while the calcaneus and navicular bones shift out of place. These dislocations account for about 15% of talus bone injuries and 1 to 2% of all joint dislocations. They are more common in young men following inversion trauma.

Objective:

This study aims to improve the understanding of diagnosis, treatment, and management of these rare injuries for better patient care.

Case presentation:

17-year-old male patient with type 1 diabetes mellitus presented to the emergency department with severe ankle pain and swelling following an inversion injury, which rendered him unable to walk or stand. Despite his chronic condition, he was hemodynamically stable, with no neurovascular deficits but an apparent deformity in the left ankle. Treatment involved pain management with morphine, successful closed reduction under ketamine sedation, and immobilization. Follow-up radiographs and a CT scan revealed no fractures but indicated soft tissue edema, joint effusion, and subsequent osteopenia. At a three-month follow-up, the patient experienced ongoing pain and weight-bearing difficulties, diagnosed as complicated pain syndrome requiring further physiotherapy and rehabilitation.

Conclusion:

This case highlights the clinical challenges and complications in managing isolated subtalar joint dislocations, particularly in patients with systemic health issues, and contributes valuable insights to the sparse literature on this topic.

1. BACKGROUND

In English medical literature, cases of isolated subtalar joint dislocations are uncommon. This type of injury, where there is no associated fracture of the nearby fifth metatarsal, talus, or malleoli, is notably rare. This rarity can be explained by the strong ligaments connecting the talus and the calcaneus, the sturdy nature of the ankle, and the snug fit of the joint capsule around these bones (1).

As described by Broca (2), such a dislocation occurs when the talus bone remains in place with the leg bones, but the calcaneus and navicular bones beneath it shift out of place. The first recorded case of a total subtalar joint dislocation dates back to 1811, as noted by Judcy (3). Although this injury is rare, its occurrence is gradually increasing. It accounts for about 15% of all talus bone injuries and 1 to 2% of all joint dislocations (4). Young men are most often affected, usually following a specific type of foot injury known as an inversion trauma when the foot is pointing downwards.

2. OBJECTIVE

The aim of this study was to analyze subtalar dislocations without associated fractures through a focused case report and literature review. It intends to clarify diagnosis, treatment, and the understanding of such injuries for improved patient care.

3. CASE PRESENTATION

A 17-year-old male patient with type 1 diabetes mellitus who was on insulin presented to our trauma centre emergency department (ED) complaining of ankle pain and swelling caused by an inversion injury experienced while walking. Following the event, he could not walk or stand on the injured foot. There has been no prior history of headaches, nausea, or vomiting. There was no previous history of chest or abdominal pain. He is hemodynamically stable, conscious, alert, and oriented. On the primary survey, his airway is maintained; he has good air entry bilaterally; there is no external bleeding; e-fast has been performed, and there is no free fluid, GCS 15/15, pupil reactive bilaterally, and no spinal tenderness.

In the secondary survey, a left ankle exam revealed an obvious deformity and tenderness on the lateral aspect of the left ankle; nevertheless, there was no neurovascular compromise, and systemic examinations were normal.

Morphine was administered to the patient for pain alleviation. Later, an x-ray of the foot and ankle was obtained, and it revealed a medial subtalar dislocation without a fracture (Figure 1).

Figure 1. X-ray of Left Foot Showing Medial Subtalar Dislocation Without a Fracture.

After a closed reduction was performed while the patient was under sedation with ketamine, post-reduction radiographs revealed that the ankle had been correctly realigned and that there was no neurovascular compromise post-reduction, a below-the-knee back-slap was then used (Figures 2 and 3).

Figure 2 and 3. Post-Reduction Radiographs Demonstrating Correct Realignment of the Ankle After Medial Subtalar Dislocation.

Before the procedure, the patient was told about the treatment plan and any risks and problems. After reduction, a computed tomography (CT) scan of the left ankle was carried out to rule out any possible fractures that would not have been seen on radiography. It showed modest soft tissue oedema with joint effusion but no evident fracture (Figure 4).

Figure 4. CT Imaging Revealing Modest Soft Tissue Edema and Joint Effusion in the Left Ankle, with No Evident Fracture.

The following investigations were ordered: CBC, RFT, LFT, PT, and PTT. All of the tests came out normal. Following up with the orthopaedic clinic after three months, the patient still complained of pain and was unable to bear total weight - skin discolouration with oedema. An x-ray of the foot and ankle was taken, and compared with the previous one, it showed reduced density and a pseudo-permeative look of the visible bones, mostly indicative of osteopenia.

The patient was ultimately diagnosed with a complex pain syndrome, a multifaceted condition often characterized by persistent and debilitating pain that does not align strictly with typical nociceptive or neuropathic patterns. This diagnosis necessitates a comprehensive and multidisciplinary approach to management, encompassing both physiotherapy and rehabilitation. The physiotherapy regimen aims to address the functional impairments and pain management, while rehabilitation focuses on restoring the patient’s ability to perform daily activities and improve quality of life. This integrated therapeutic strategy is crucial for effective management and recovery in cases of complex pain syndromes following orthopedic injuries.

Figure 5. X-ray Showing Reduced Bone Density and a Pseudo-Permeative Appearance of the Visible Bones, Indicative of Osteopenia.

4. DISCUSSION

Subtalar dislocation without fractures is a rare injury that requires careful diagnosis and appropriate management. The subtalar joint is a complex articulation, and dislocations can occur in various directions, including medial, lateral, anterior, and posterior dislocations (5). These dislocations can occur with or without concomitant fractures (5). For instance, a case report by described a 37-year-old male patient who sustained a subtalar dislocation without any bony injury while playing football (6). On the other hand, found that the subtalar joint demonstrated radiographic changes in 89% of patients, with 63% being symptomatic, and 75% of patients with subtalar joint changes incurred a fracture about the subtalar joint at the time of dislocation (7).

In cases of malunited lateral or posterior process fractures and progressive cartilage wear after subtalar dislocations, in situ fusion of the subtalar joint is the treatment of choice (8). Furthermore, noted that subtalar dislocations make up 1-2% of all dislocations, with about 75% of them being medial dislocations Rammelt & Goronzy (9). Additionally, reported a rare case of a 36-year-old male patient who sustained a closed medial subtalar dislocation without any associated fractures of the ankle (10). It is important to note that subtalar joint dislocation (STJD) is an uncommon injury, defined as simultaneous dislocation of the talonavicular and talocalcaneal joints without talar neck fracture (11).

High-energy mechanisms of trauma can lead to lateral subtalar dislocations often presenting with associated foot injuries, such as fractures of the ankle, talus, cuboid, cuneiforms, navicular, and metatarsals (12). Furthermore, presented a case of an irreducible medial subtalar dislocation following a motor vehicle accident with no associated fractures demonstrated on radiograph (13). Subtalar joint dislocations are frequently accompanied by fractures of the adjacent tarsal and metatarsal bones (14). Additionally, subtalar dislocations commonly have associated fractures, and the Hawkins classification system is commonly used to classify these fractures (15).

The treatment of subtalar dislocations varies depending on the specific case. Conservative treatment is an option for subtalar dislocations that do not involve the calcaneo-cuboid or tibio-talar joints and do not include a fracture of the neck of the talus (16). However, in cases of complete open medial subtalar dislocation, treatment with an external fixator may be necessary (17). It is also important to note that as much as 80% of subtalar dislocations display restriction in motion after healing, and 50-80% have radiographic evidence of post-traumatic subtalar arthritis (18).

5. CONCLUSION

Subtalar dislocation without fractures is a rare but complex injury that requires careful diagnosis and appropriate management. The treatment approach may vary depending on the specific characteristics of the dislocation and the presence of associated fractures.

Diagnostic Challenges in Subtalar Dislocations: This case underscores the importance of accurate diagnosis in subtalar dislocations, particularly when they occur without associated fractures, and the necessity of using multiple imaging modalities for comprehensive assessment.

Management of Pain in Orthopedic Injuries: Effective pain management, as demonstrated in this case through the use of morphine and ketamine, is crucial for patient comfort and successful treatment outcomes in orthopedic injuries.

Complications in Diabetic Patients: The case highlights the increased risk of complications, like osteopenia and complex pain syndrome, in diabetic patients following orthopedic injuries, necessitating careful monitoring and follow-up.

Importance of Physiotherapy and Rehabilitation: The role of physiotherapy and rehabilitation is emphasized in the management of long-term complications such as pain and mobility issues post-injury.

Awareness of Rare Injury Patterns: This case contributes to the sparse literature on isolated subtalar dislocations, highlighting the need for awareness among clinicians about such rare injury patterns for timely and effective management. Top of Form.

Data Access Statement:

Data supporting this study’s findings are available upon reasonable request.

Ethics Statement:

This study was conducted in accordance with ethical standards and approved by the relevant Institutional Review Board.

Author's Contribution:

The authors contributed equally to the research, writing, and review of this manuscript. Final proofreading was made by the first author.

Conflict of Interest Statement:

The authors declare no conflict of interest.

Financial support and sponsorship:

This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.