Introduction 

Lisfranc injuries are midfoot injuries affecting the union between the metatarsal and tarsal bones. They can range from subtle ligament sprains, which are typically seen in individuals such as athletes due to low-energy mechanisms, to fracture-dislocation, usually in high-energy injuries.¹ 

Diabetic individuals can be prone to foot injuries, largely due to complications such as peripheral neuropathy. The neuropathic origin can lead to a loss of protective sensation, making patients unaware of minor trauma or stress to the foot. As a result, patients may face medical, social or economic complications impacting their families and the healthcare system.²

Furthermore, diabetes can play a role in the structural and vascular changes in the foot. For instance, it causes the soft tissue to stiffen, which leads to joint instability and impaired circulation. These factors can all increase the risk of injury and delay healing.

Anatomy and biomechanics of the Lisfranc joint 

Overview of the Lisfranc joint complex 

The Lisfranc joint refers to the connection between the first, second, and third metatarsal bones and the corresponding medial, intermediate, and lateral cuneiforms. These are specific bones in your foot. It is responsible for the structural and functional connections between the forefoot and midfoot.³

This area maintains stability due to both the bony configuration and a network of strong ligaments. The Lisfranc ligament runs from the medial cuneiform to the base of the second metatarsal. This stops the separation and maintains the joint integrity. If the ligament is disrupted, it can result in instability and cause impairment to the gait mechanisms. As a result, it can cause long-term deformity if it is not immediately recognised and treated.⁴

Biomechanical function 

The Lisfranc joint plays an important role in the biomechanics of the foot. It can provide structural support during gait (walking), especially when transferring force from the hindfoot to the forefoot. This specific joint is particularly active during the stance phase of walking. It helps to maintain alignment and evenly distribute the weight across the foot.⁵

Furthermore, the Lisfranc joint is crucial for the stability of the midfoot, and it can contribute significantly to the push-off phase of gait. Correct functioning of the joint enables efficient propulsion and balance. If the joints are disturbed anyway, such as sprains or dislocations, it can contribute to altered gait patterns, instability and long-term functional impairment.⁶

Susceptibility to abnormal foot biomechanics 

Any changes in the biomechanics of a normal foot can be noticed in conditions such as peripheral neuropathy, diabetes, or deformities. They can result in an uneven load across the midfoot. An unequal distribution can increase the risk of mechanical stress on the Lisfranc joint. 

As a result, it can reduce the ability to absorb and transfer forces efficiently and successfully. Therefore, individuals become more vulnerable to joint injuries. Hence, low-energy situations can be stressful.⁷

Physiological alterations of neuropathic and diabetic feet

Peripheral neuropathy 

Diabetic patients diagnosed with peripheral neuropathy have a weak ability to perceive proprioception and pain. Therefore, they are unable to identify and detect injuries or stress that is induced in their foot due to an impairment in their sensation. 

This can lead to an unrecognised trauma such as microfractures, ligamentous injuries, or joint dislocations. Over a long period, this trauma can increase the risk of fractures such as Lisfranc injuries.⁸ 

Diabetic foot 

Diabetic individuals tend to have stiffness of soft tissues due to an alteration in collagen, which reduces flexibility and decreases shock absorption. As a result, it can increase the likelihood of joint strain and injury, especially in the midfoot.⁹ 

Additionally, vascular insufficiency can lead to impaired blood flow, resulting in tissue perfusion and delaying wound healing. Eventually, this deficiency can increase infections and cause chronic ulceration.¹⁰

Lastly, diabetic patients can present with muscle atrophy, especially in the intrinsic foot muscles. This can lead to structural imbalance and alter gait mechanics. Complications can arise, such as difficulty walking, which can increase stress on vulnerable areas like the Lisfranc joints, heightening the risk of injury.¹¹

Charcot neuroarthropathy

Charcot neuroarthropathy is a destructive complication of the joints, found in diabetic individuals with peripheral neuropathy. The condition is recurring, due to microtrauma, and is difficult to identify. Therefore, individuals remain untreated. As a result, inflammation, bone resorption, joint subluxation, and eventual collapse can occur in the structures.¹²

The midfoot is most commonly affected in Charcot neuroarthropathy, with the Lisfranc joint complex being especially vulnerable. If this area is damaged, it can result in deformity and instability.¹³ This abnormality in the foot's structure can worsen an individual's risk of skin breakdown, ulceration, and subsequent infection. Hence, an early appropriate diagnosis is crucial, so that the injury can be managed and the foot maintains functional mobility.

Epidemiology and risk factors 

Prevalence in the diabetic population

Diabetic individuals are more likely to be diagnosed with Lisfranc injury compared to the general population. This includes midfoot fractures, dislocations, and joint disruptions, particularly involving the Lisfranc complex. Peripheral neuropathy, vascular insufficiency, and altered biomechanics can present alongside Lisfranc injuries, further increasing the risk. However, if this injury is not identified, diagnosis can be delayed, resulting in late treatment and management.¹³ 

Risk factors

Factors that can contribute to Lisfranc injuries and diabetic foot:¹⁴

• Long-standing diabetes: Prolonged hyperglycemia can lead to peripheral neuropathy and vascular disease
• History of peripheral neuropathy: Loss of protective sensation can result in trauma or stress
• Obesity and altered biomechanics: Excess body weight can result in problems arising in the mechanical movement of the foot, leading to muscle imbalance and deformities
• Improper footwear: Inappropriate shoes can worsen or result in injury 

Lisfranc injuries can often be missed

Lisfranc injuries can be undiagnosed due to the absence of pain and atypical clinical presentation in diabetic individuals with peripheral neuropathy. This can be due to misdiagnosis or an incorrect understanding of the symptoms. 

For instance, diabetic patients may present swelling, warmth, or redness, which may be misunderstood to mimic cellulitis, gout, or early Charcot arthropathy.

Furthermore, few diabetic patients are aware of the symptoms, and only a few signs on standard radiographs result in delayed or missed diagnosis. With slow and delayed identification, the injury can worsen and lead to deformity, instability, and long-term disability.¹⁵ 

Mechanism of injury 

Diabetic patients with peripheral neuropathy and Lisfranc injuries tend to have lower-energy mechanisms rather than high-impact trauma. For instance, they have struggled to walk on uneven surfaces or perform twisted movements, which may result in increased stress on the foot.¹⁶ 

Furthermore, repetitive microtrauma from unusual gait patterns and poor foot biomechanics can result in cumulative joint stress. Sensory impairment is a contributing factor to neuropathy. They can cause pain to not be perceived properly, which is one of the main reasons for delayed diagnosis, as it goes undiagnosed.¹⁷ 

Therefore, injuries that cause joint degeneration and weakened ligaments result in instability in the midfoot. The collapse of the medial longitudinal arch can cause displacement or dislocation at the Lisfranc joint. 

Diagnosis and clinical presentation 

Lack of pain is a hallmark of peripheral neuropathy and delays the diagnosis of Lisfranc injuries. Hence, symptoms worsen without treatment and management. 

Non-specific signs, such as swelling, redness, and warmth, can result in misdiagnosis as well. Cormorbidities can be cellulitis, gout, or even deep vein thrombosis.¹⁸ 

Physical examination can help identify instabilities in the midfoot, helping the diagnose Lisfranc injuries. 

Imaging studies are useful for a more accurate diagnosis:¹⁹

• Weight-bearing X-rays can detect separation or misalignment of the tarsometatarsal joints
• MRI scans can identify ligamentous disruption, bone oedema, or early charcot changes 

Summary

Lisfranc injuries are an underrecognised complication in diabetic patients and neuropathic feet. Early recognition is crucial to prevent delayed diagnosis, which can lead to progressive deformity, ulceration, infection, and even limb loss.

By improving awareness and early intervention, we can significantly reduce the long-term disability and socioeconomic burden associated with Lisfranc injuries in this high-risk population.