Introduction 

A common, yet lesser-known, complication of diabetes is nerve damage, particularly to nerves in the peripheral nervous system. Peroneal nerve injury is associated with diabetes and can lead to foot drop, numbness, and mobility issues, which could have a significant impact on quality of life. This article aims to address concerns regarding peroneal nerve injury in diabetes and provide information on its diagnosis and treatment.

Neuropathy and diabetes

Neuropathy is a neurological condition characterised by damaged nerves, which can lead to impaired sensation and potentially cause pain or numbness.¹ Neuropathy can occur in type 1 and type 2 diabetes; however, it is more often seen in type 2 diabetes.² There are different types of neuropathy associated with diabetes, which include peripheral neuropathy, autonomic neuropathy, and focal neuropathy.³ 

• Peripheral neuropathy refers to damage to nerves relating to the peripheral nervous system, which includes the nerves outside of the brain and spinal cord¹
• Autonomic neuropathy refers to nerve damage relating to the autonomic nervous system, which impacts multiple organ systems, including the cardiovascular and gastrointestinal systems. It is primarily responsible for the involuntary processes that happen in the body, such as heart rate, digestion, and the bladder^2,4 
• Focal neuropathy is a form of mononeuropathy, meaning it involves damage to individual nerves; this type of neuropathy tends to affect specific nerves, often in the torso, head, or legs⁵

Peripheral neuropathy is one of the most common complications of diabetes, affecting around 50% of people with diabetes.^6,7 Diabetic neuropathy, particularly diabetic peripheral neuropathy (DPN), occurs because high blood sugar can damage the blood vessels that deliver oxygen and essential nutrients to the peripheral nerves, ultimately resulting in nerve dysfunction. DPN primarily impacts the nerves relating to sensory and motor functions in the legs and feet. One nerve that is impacted by diabetic neuropathy is the peroneal nerve, which is mainly responsible for supplying movement and sensation to the toes, lower foot, and leg.⁸ 

Peroneal nerve injury and diabetes 

The peroneal nerve is a major nerve of the leg and is a branch of the sciatic nerve. The location of the peroneal nerve, at the head of the fibula, makes it more susceptible to injury and nerve damage.⁹ Peroneal nerve injury is classified as a focal neuropathy and is one of the most common mononeuropathies of the lower extremity. In diabetes, the higher levels of blood glucose can cause the peroneal nerve to swell, ultimately leading to entrapment and compression of the peroneal nerve. The combination of the swelling of the nerve and its sensitive location further increases its susceptibility to damage.¹⁰ 

Symptoms 

There are a few symptoms associated with peroneal nerve injury, with the most common symptom being foot drop. Foot drop refers to an impairment in one’s ability to dorsiflex their foot (lift their toes or raise their foot from the ankle). 

Other symptoms include:¹¹

• Numbness and loss of sensation in the foot 
• Pain or weakness, particularly in the shin, ankle, or top of the foot 
• Inability or impaired ability to move the foot 

Diagnosis 

To accurately diagnose a peroneal nerve injury, it is important to consult a physician. The process for diagnosis could include an evaluation of medical history, clinical examinations, and various neurological tests.¹¹

The main diagnostic tests: 

• Clinical examination could include the physician examining your leg for oedema (swelling), weakness in the lower areas of the leg, and assessing sensation in the affected area¹²
• Electromyography (EMG) is a test used to evaluate the health of your muscles through observing and measuring the muscle’s response to nerve stimulation. In peroneal nerve injuries, electromyography allows physicians to assess the extent of nerve damage as well as the chronicity of the injury¹³
• Nerve conduction studies (NCSs) are non-invasive tests used to assess the response of peripheral nerves to electrical stimulation, which can be helpful in determining the functionality of the peripheral nerves¹⁴
• Imaging tests, such as ultrasound, CT scan and MRI scan, can be used in some cases to assist in diagnosis¹

Treatment 

The good news is that most cases of peroneal nerve injury can be treated, and the function of the peroneal nerve can be partially or fully restored; this, however, depends on the severity of the nerve damage and impairment.¹⁵

Treatments could be surgical or non-surgical, depending on the severity of the case, and include:¹⁵

• Physical therapy involves a range of activities, such as stretching, balancing, and strengthening exercises. Additionally, other forms of physical therapy that don’t involve exercise could include icing, taping, or using a brace on the affected areas
• Ankle-foot orthoses (AFO) are devices that help toes move and help the ankle stay stable when in a standing position
• Peroneal nerve decompression is a surgical approach to treating peroneal nerve injury. It is mainly used in more severe cases, when non-surgical approaches have been exhausted and have not resulted in significant improvements

Whilst peroneal nerve injury is a serious complication of diabetes, it is manageable and treatable. With effective treatment and long-term care, impairment of the nerves can be significantly reduced and, ultimately, improve quality of life.¹⁵

Summary

• High blood sugar in diabetes can lead to nerve damage and result in diabetic neuropathy. One form of diabetic neuropathy is injury to the peroneal nerve
• The peroneal nerve is found in the lower extremity of the leg, and damage to this nerve can impact sensation and mobility in the foot, toes, and ankle
• Symptoms of peroneal nerve injury include foot drop, loss of sensation, and weakness
• Diagnostic evaluations include clinical examinations, electromyography, nerve conduction studies, and imaging tests
• Peroneal nerve injury can be treated through physical therapy, AFO, and possibly surgical interventions, such as the peroneal nerve decompression
• Overall, with good care and management, peroneal nerve injury can be treated