What is plantar fasciitis

Plantar fasciitis is a localized, degeneration of the plantar fascia origin at the medial calcaneal tuberosity of the heel, the tough, fibrous band of tissue that connects your heel bone to the base of your toes. Plantar fasciitis occurs at the site where the plantar fascia is attached to the bottom of the heel bone. Plantar fasciitis is the most common cause of heel pain, affecting more than three million people every year according to statistics. Plantar fasciitis frequency is similar to those who suffer from lower back pain, which could mean many more people are suffering from the condition.

The plantar fascia is a piece of strong and thick tissue that runs along the bottom of the foot. The plantar fascia plays an important role in the normal biomechanics of the foot and is composed of three segments, all of which arise from the calcaneus. The plantar fascia connects the heel bone to the toes, creating the foot’s arch and providing shock absorption.

Under normal circumstances, your plantar fascia acts like a shock-absorbing bowstring, supporting the arch in your foot. If tension and stress on that bowstring become too great, small tears can arise in the fascia. Repetitive stretching and tearing can cause the fascia to become irritated or inflamed, though in many cases of plantar fasciitis, the cause isn’t clear.

Plantar fasciitis is degenerative irritation of the plantar fascia, either through overstretching, overuse or a medical condition. Despite the name plantar fasciitis, this condition is notably characterized by an absence of inflammatory cells ¹.

Common symptoms of plantar fasciitis include mild pain on the bottom of the heel, especially when taking your first steps of the day. Often, symptoms improve only to worsen later in the day. This happens due to over-stressing of the plantar fascia causing a chronic healing response at the attachment to the bone that may remain sore for months.

Plantar fasciitis can be caused by:

• Playing sports that put stress on the heel bone, like running, dance and aerobics.
• Flat-footed or high arches.
• Being middle-aged or older.
• Being overweight.
• Pregnancy.
• Spending a lot of time on your feet.
• Wearing shoes with poor arch support or stiff soles.

Plantar fasciitis is often associated with a heel spur which is a spike of bone poking out from the heel bone, but many people have heel spurs without any pain.

All foot types are prone to plantar fasciitis, including folks with high arches and those with what we call flat feet. The condition is common in middle-aged and older patients. It is also common in patients who walk or stand on hard surfaces a lot. It disproportionately affects those who are overweight.

Plantar fasciitis accounts for about 10% of runner-related injuries and 11% to 15% of all foot symptoms requiring professional medical care ². Plantar fasciitis is thought to occur in about 10% of the general population as well, with 83% of these patients being active working adults between the ages of 25 and 65 years old. Plantar fasciitis may present bilaterally in a third of the cases. Some literature shows prevalence rates among a population of runners to be as high as 22% ³.

Most people who have plantar fasciitis recover with conservative treatments, including resting, icing the painful area and stretching, in several months (within 12 months of initial presentation and often sooner) ⁴.

Figure 1. Plantar fascia

Figure 2. Plantar fasciitis

Plantar fasciitis types

There are two types of plantar fasciitis — acute and chronic.

• Acute plantar fasciitis: The condition can be triggered by a specific injury, this is also called an acute type.
• Chronic plantar fasciitis: There is also a chronic type also known as the classic case of plantar fasciitis which becomes worse over time.

If you have plantar fasciitis, there are things you can do to help relieve the pain and heal your foot.

Plantar fasciitis cause

Plantar fasciitis is often an overuse injury that is primarily due to a repetitive strain causing micro tears of the plantar fascia but can occur as a result of trauma or other multifactorial causes ². Some predisposing factors are flat feet (pes planus), high arch foot (pes cavus), limited ankle dorsiflexion, and excessive pronation or supination. Flat feet (pes planus) can cause increased strain at the origin of the plantar fascia. High arch foot (pes cavus) can cause excessive strain on the heel because the foot does not effectively evert or absorb shock. Tight gastrocnemius, soleus, and/or other posterior leg muscles have also been commonly found in patients with plantar fasciitis. It is thought that these tight muscles can alter the normal biomechanics of ambulation.

Approximately 50% of patients with plantar fasciitis will also have heel spurs, but the spurs themselves are not the cause. Plantar fasciitis is often associated with runners and older adults, but other risk factors include obesity, occupations requiring prolonged standing, and weight-bearing. Other causes include a pinched nerve in the heel region, thinning of the heel fat pad, or a stress fracture of the heel bone. Plantar fasciitis has also been found to be associated with various seronegative spondyloarthropathies, but in approximately 85% of cases, there are no known systemic factors ⁵.

Plantar fasciitis pathophysiology

Plantar fasciitis is primarily a degenerative process. Aside from degenerative changes, histological findings include granulation tissue, micro-tears, collagen disarray, and notably a lack of traditional inflammation. Ultrasound evaluation often reveals calcifications, intrasubstance tears, and thickening and heterogeneity of the plantar fascia. These changes, often seen on ultrasound, suggest a non-inflammatory condition and dysfunctional vasculature.

Risk factors for plantar fasciitis

Though plantar fasciitis can arise without an obvious cause, factors that can increase your risk of developing plantar fasciitis include:

• Age. Plantar fasciitis is most common between the ages of 40 and 60.
• Certain types of exercise. Activities that place a lot of stress on your heel and attached tissue — such as long-distance running, ballistic jumping activities, ballet dancing and aerobic dance — can contribute to an earlier onset of plantar fasciitis.
• Foot mechanics. Being flat-footed, having a high arch or even having an abnormal pattern of walking can affect the way weight is distributed when you’re standing and put added stress on the plantar fascia.
• Obesity. Excess pounds put extra stress on your plantar fascia.
• Occupations that keep you on your feet. Factory workers, teachers and others who spend most of their work hours walking or standing on hard surfaces can damage their plantar fascia.

Plantar fasciitis prevention

Take good care of your feet. Wear shoes with good arch support and heel cushioning. If you work on hard surfaces, stand on a thick rubber mat to reduce stress on your feet. Make sure that you stretch daily whether you are an athlete or not. Stay at a healthy weight to reduce the load on your feet.

Plantar fasciitis symptoms

The main symptom of plantar fasciitis is pain under the heel, which can be dull or sharp. The foot sole may ache or burn and your heel may be slightly swollen.

The pain is often worse:

• in the morning, as you take your first steps
• after prolonged standing or sitting
• after intense activity.

Plantar fasciitis complications

Ignoring plantar fasciitis may result in chronic heel pain that hinders your regular activities. Changing the way you walk to minimize plantar fasciitis pain might lead to foot, knee, hip or back problems.

Plantar fasciitis diagnosis

To check whether you have plantar fasciitis, your doctor will probably ask you some questions, for example, about your symptoms, the type of work you do and your lifestyle.

Also, it’s likely they’ll perform a physical exam to check the arches of your feet and to see whether there is any redness, swelling, tenderness, stiffness or tightness.

Patients will often present with a history of progressive pain at the inferior and medial heel, but can, however, radiate proximally in more severe cases. They will often describe the pain as sharp and worst with the first few steps out of bed in the morning. Long periods of standing, or in severe cases, sitting for prolonged periods, will also exacerbate symptoms. Pain often decreases with ambulation or beginning an athletic activity, but then increases throughout the day as activity increases. Pain can usually be reproduced by palpating the plantar medial calcaneal tubercle at the site of the plantar fascial insertion on the heel bone. Pain can also be reproduced with passive dorsiflexion of the foot and toes. Specifically, passive dorsiflexion of the first metatarsophalangeal joint is known as the windlass (or Jack’s) test and considered a positive test if pain is reproduced. Secondary findings may include a tight Achilles heel cord, pes planus, or pes cavus. It may also be beneficial to assess a patient’s gait to assess for biomechanical factors or predisposing factors mentioned previously. When considering the diagnosis of plantar fasciitis, one should consider fat pad contusion or atrophy, stress fractures, and nerve entrapments such as tarsal tunnel syndrome in the differential.

Usually no tests are necessary. Your doctor might suggest an X-ray, ultrasound scan or magnetic resonance imaging (MRI) to make sure your pain isn’t being caused by another problem, such as a stress fracture or a pinched nerve.

X-rays and/or ultrasound evaluation may show calcifications in the soft tissues or heel spurs on the inferior aspect of the heel. Additionally, ultrasound may show thickening and swelling of the plantar fascia which is a typical feature. If the patient is not responding to conservative therapy after longer periods of time, then the provider may consider ordering an MRI to evaluate for tears, stress fractures, or osteochondral defects ⁶.

Sometimes an X-ray shows a spur of bone projecting forward from the heel bone. In the past, these bone spurs were often blamed for heel pain and removed surgically. But many people who have bone spurs on their heels have no heel pain.

Plantar fasciitis treatment

More than 90% of patients with plantar fasciitis will improve within 10 months of starting simple treatment methods.

Initially, your doctor may recommend one or more of the following treatments:

• Pain-relief medicine, such as anti-inflammatory medication like ibuprofen (Advil, Motrin IB, others) and naproxen sodium (Aleve) or acetaminophen (paracetamol)
• Physiotherapy with specific stretching exercises
• Resting your foot as much as possible. Decreasing or even stopping the activities that make the pain worse is the first step in reducing the pain. You may need to stop athletic activities where your feet pound on hard surfaces (for example, running or step aerobics).
• Shoes with good support and cushioning
• Night splints to wear while sleeping. Most people sleep with their feet pointed down. This relaxes the plantar fascia and is one of the reasons for morning heel pain. A night splint stretches the plantar fascia while you sleep. Although it can be difficult to sleep with, a night splint is very effective and does not have to be used once the pain is gone.
• Cushioned soled shoes, heel cups or heel pads, and soft orthotics are useful in alleviating symptoms. Shoes with thick soles and extra cushioning can reduce pain with standing and walking. As you step and your heel strikes the ground, a significant amount of tension is placed on the fascia, which causes microtrauma (tiny tears in the tissue). A cushioned shoe or insert reduces this tension and the microtrauma that occurs with every step. Soft silicone heel pads are inexpensive and work by elevating and cushioning your heel. Pre-made or custom orthotics (shoe inserts) are also helpful.
• An icepack applied to your foot. Rolling your foot over a cold water bottle or ice for 20 minutes is effective. This can be done 3 to 4 times a day.

If these measures don’t work or your condition doesn’t improve after 12 weeks, your doctor may give you steroid injections in your heel. But, beware that having multiple injections may weaken the fibers of the fascia even more. Other interventions such as a night splint or shock wave therapy may also help.

Very occasionally, people have surgery to try to fix it. As a practice, doctors do not explore surgery for plantar fasciitis unless noninvasive treatments have failed, but statistics show that about 5 in 100 sufferers may be candidates.

Figure 3. Plantar fasciitis night splint

Plantar fasciitis stretches

Stretching is by far the best therapy to relieve the painful plantar fasciitis symptoms without damaging the integrity of the plantar fascia. Simple, corrective stretches to loosen up the calf muscle, the Achilles tendon and of course the plantar fascia itself.

A simple stretch that can be done at your desk involves folding one foot over the opposite knee with your toes flexed back towards you in a figure four formation. Another is the yoga pose called downward dog. The classic runner’s stretch also helps stretch the lower leg and bottom of the foot.

Plantar fasciitis exercises

Toe curls with towel

1. Place a small towel on the floor. Using involved foot, curl towel toward you, using only your toes. Relax.
2. Repeat 10 times, 1-2 times per day.

Figure 4. Toe curls with towel

Toe Extension

1. Sit with involved leg crossed over uninvolved leg. Grasp toes with one hand and bend the toes and ankle upwards as far as possible to stretch the arch and calf muscle. With the other hand, perform deep massage along the arch of your foot.
2. Hold 10 seconds. Repeat for 2-3 minutes. Repeat 2-4 sessions per day.

OR

1. Stand with your foot directly in front of a wall. Make sure your shoe is off.
2. Slowly position your foot so that your big toe is resting on the wall and the ball of your foot is a few centimeters from the floor. Your big toe should be bending gently backward.
3. A gentle stretch should be felt on the bottom of your foot. Hold this position for 15 seconds, and then take your foot away from the wall.
4. Repeat the stretch five times.

Figure 5. Toe extension

Standing calf stretch

1. Stand placing hands on wall for support. Place your feet pointing straight ahead, with the involved foot in back of the other. The back leg should have a straight knee and front leg a bent knee. Shift forward, keeping back leg heel on the ground, so that you feel a stretch in the calf muscle of the back leg.
2. Hold 45 seconds, 2-3 times. Repeat 4-6 times per day.

Figure 6. Standing calf stretch

Calf stretch on a step

1. Stand with uninvolved foot flat on a step. Place involved ball of foot on the edge of the step. Gently let heel lower on involved leg to feel a stretch in your calf.
2. Hold 45 seconds, 2-3 times. Repeat 4-6 times per day.

Figure 7. Calf stretch on a step

Towel stretch

The towel stretch is effective at reducing morning pain if done before getting out of bed.

1. Sit with involved leg straight out in front of you. Place a towel around your foot and gently pull toward you, feeling a stretch in your calf muscle.
2. Hold 45 seconds, 2-3 times. Repeat 4-6 times per day.

Figure 8. Towel stretch

Ice massage arch roll

1. With involved foot resting on a frozen can or water bottle, golf ball, or tennis ball, roll your foot back and forth over the object.
2. Repeat for 3-5 minutes, 2 times per day.

Figure 9. Ice massage arch roll

Plantar fasciitis home remedies

To reduce the pain of plantar fasciitis, try these self-care tips:

• Maintain a healthy weight. Lose weight if you’re overweight or obese to minimize stress on your plantar fascia.
• Choose supportive shoes. Avoid high heels. Buy shoes with a low to moderate heel, good arch support and shock absorbency. Don’t go barefoot, especially on hard surfaces.
• Don’t wear worn-out athletic shoes. Replace your old athletic shoes before they stop supporting and cushioning your feet. If you’re a runner, buy new shoes after about 400 to 500 miles of use.
• Change your sport. Try a low-impact sport, such as swimming or bicycling, instead of walking or jogging.
• Apply ice. Hold a cloth-covered ice pack over the area of pain for 15 to 20 minutes three or four times a day or after activity. Or try ice massage. Freeze a water-filled paper cup and roll it over the site of discomfort for about five to seven minutes. Regular ice massage can help reduce pain and inflammation.
• Stretch your arches. Simple home exercises can stretch your plantar fascia, Achilles tendon and calf muscles.

Other procedures

When more-conservative measures aren’t working after several months, your doctor might recommend:

Injections

Injecting a type of steroid medication into the tender area can provide temporary pain relief. Multiple injections aren’t recommended because they can weaken your plantar fascia and possibly cause it to rupture. More recently, platelet-rich plasma has been used, under ultrasound guidance, to provide pain relief with less risk of tissue rupture.

Corticosteroid injections have been shown to be beneficial in the short-term (less than four weeks) but ineffective in the long term ².

Extracorporeal shock wave therapy

In this procedure, sound waves are directed at the area of heel pain to stimulate healing. It’s usually used for chronic plantar fasciitis that hasn’t responded to more-conservative treatments. This procedure might cause bruising, swelling, pain, numbness or tingling. Some studies show promising results, but it hasn’t been shown to be consistently effective.

Evidence of the efficacy of platelet rich plasma, dex prolotherapy, and extra-corporeal shockwave therapy is conflicting ².

Tenex procedure

This minimally invasive procedure removes the scar tissue of plantar fasciitis without surgery.

Plantar fasciitis surgery

Few people need surgery to detach the plantar fascia from the heel bone. It’s generally an option only when the pain is severe and all else fails ⁷. Surgery is considered only after 12 months of aggressive nonsurgical treatment.

Most patients have good results from surgery. However, because surgery can result in chronic pain and dissatisfaction, it is recommended only after all nonsurgical measures have been exhausted.

Complications of surgery include a weakening of the arch in your foot.

Gastrocnemius recession

This is a surgical lengthening of the calf (gastrocnemius) muscles. Because tight calf muscles place increased stress on the plantar fascia, this procedure is useful for patients who still have difficulty flexing their feet, despite a year of calf stretches.

In gastrocnemius recession, one of the two muscles that make up the calf is lengthened to increase the motion of the ankle. The procedure can be performed with a traditional, open incision or with a smaller incision and an endoscope, an instrument that contains a small camera. Your doctor will discuss the procedure that best meets your needs.

Complication rates for gastrocnemius recession are low, but can include nerve damage.

Plantar fascia release

If you have a normal range of ankle motion and continued heel pain, your doctor may recommend a partial release procedure. During surgery, the plantar fascia ligament is partially cut to relieve tension in the tissue. If you have a large bone spur, it will be removed, as well. Although the surgery can be performed endoscopically, it is more difficult than with an open incision. In addition, endoscopy has a higher risk of nerve damage.

The most common complications of release surgery include incomplete relief of pain and nerve damage.

Plantar fasciitis prognosis

Plantar fasciitis may be a benign disorder but if not adequately managed can be disabling and associated with moderate to severe pain. About 70-80% of patients with plantar fasciitis see symptom reduction in 9-12 months, but at least 5-10% require surgical release of the plantar fascia ⁸. Plantar fasciitis in athletes is associated with high morbidity and even when managed appropriately recurrences are not uncommon. The morbidity of plantar fasciitis is due to pain in the foot, difficulty with ambulation, limitation in exercise and inability to weight bear. Sometimes, the uneven ambulation can also leas to an injury of the knee and hip joints. Among people who have to stand for long hours, plantar fasciitis is one of the most common causes of worker’s compensation claims ⁹.

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Radial nerve

The radial nerve arises from ventral rami of C5 to C8 (+/- T1) and is a continuation of the posterior cord of the brachial plexus and is the largest branch of the brachial plexus, innervating almost the entire posterior side of the upper limb and provides a motor function to the extensor muscles of the forearm, wrist, fingers, and thumb.

Within the axilla, the radial nerve has three branches: sensory posterior cutaneous nerve of the arm and motor branch to the long and medial head of the triceps ¹. The radial nerve passes anterior to the subscapularis, latissimus dorsi and teres major. This is the first possible site of compression. An anomalous muscle, the accessory subscapularis-teres-latissimus is reported in literature to be another cause of compression of the radial nerve at this level ². Another potential cause of compression, as described by Spinner ³ is penetration of the nerve directly by the subscapular artery more distally in the axilla, forming a neural loop.

The radial nerve enters the posterior compartment of the arm by traveling through the triangular interval bounded by the teres major superiorly, the long head of the triceps medially and the lateral head of the triceps laterally. The radial nerve then exits the axilla, courses through the lateral head of triceps brachii and winds around the posterior humerus in the radial groove accompanied by the profunda brachii artery, sending branches to the triceps brachii. Lorem et al. ⁴ described this as another possible site of entrapment. Familial radial nerve entrapment syndrome ⁵ also occurs secondary to compression at the lateral head of the triceps. Intermittent compression of the nerve may also occur secondary to genetic defect in Schwann cell myelin metabolism ⁶. The radial nerve gives off the following branches in the upper arm – the inferior lateral cutaneous nerve of the arm, posterior cutaneous nerve of the forearm and motor branches to the lateral head of triceps and anconeus. The radial nerve is in close proximity to the humerus in the spiral groove and is easily identified on ultrasound in its short axis overlying the humerus between the lateral and medial heads of the triceps. The radial nerve then courses from the posterior to anterior compartment of the arm by piercing the lateral intermuscular septum which is another possible site of entrapment.

The radial nerve then curves anteriorly around the lateral epicondyle at the elbow, where it divides into a superficial and a deep branches (posterior interosseous nerve) under the margin of the brachioradialis muscle in the lateral border of the cubital fossa.

The deep branch (posterior interosseous nerve) is predominantly motor and passes between the two heads of the supinator muscle to access and supply muscles in the extensor muscles on the forearm. The deep branch (posterior interosseous nerve) winds around the radial head, lying between two heads of the supinator muscle and then travels on the dorsal surface of the interosseous membrane. The superficial layer of the supinator muscle forms the arcade of Frohse which is the most common site of entrapment neuropathy causing the radial tunnel syndrome ⁷. Two anomalous courses of the posterior interosseous nerve have been reported in the literature by Woltman and Learmonth. First is passage of the nerve within the substance of the supinator, and the other involves a branch travelling superficial to the supinator brevis ⁸. The origin of the radial tunnel is where the deep branch (lateral) courses over the radio-humeral joint. The tunnel ends at the distal edge of the superficial supinator where the posterior interosseous nerve is formed. Radial tunnel syndrome can be caused by the arcade of Frohse, fibrous fascial bands coursing superficial to the nerve or the vascular leash of Henry ⁹ which is formed by the recurrent radial vessels. The posterior interosseous nerve supplies the abductor pollicis longus, the extensor pollicis brevis, the extensor indicis proprius and the extensor pollicis longus.

The superficial branch of the radial nerve is sensory. The superficial radial nerve descends medially along the lateral edge of the radius under cover of the brachioradialis muscle and in association with the radial artery. Approximately two-thirds of the way down the forearm, the superficial branch of the radial nerve passes laterally and posteriorly around the radial side of the forearm deep to the tendon of the brachioradialis . The superficial radial nerve continues into the hand where it pierces the lateral fascia to enter the anatomical snuffbox and gives sensory innervation to the dorsal surface of three and a half digits on the radial aspect. It also innervates the extensor digitorum, the extensor digiti minimi and the extensor carpi ulnaris muscles.

Figure 1. Radial nerve

Figure 2. Radial nerve in the arm and posterior shoulder

Figure 3. Radial nerve in the forearm

Figure 4. Radial nerve distribution

Figure 5. Radial nerve innervation

Radial nerve injury

Trauma to the radial nerve results in wrist-drop, an inability to extend the hand at the wrist (Figure 6). If the lesion occurs far enough superiorly, the triceps muscle is paralyzed, so that the forearm cannot be actively extended at the elbow. Many fractures of the humerus follow the radial groove and the radial nerve may become stretched or transected in this region, leading to permanent damage and loss of function. The radial nerve can also be crushed in the axilla by improper use of a crutch or if a person falls asleep with an arm draped over the back of a chair.

Fracture of humerus shaft is the most common cause of radial nerve injury in the upper arm ¹⁰. Humeral fractures are due to a fall (87%), motor accidents (8%) or direct trauma (5%) ¹¹. The overall prevalence of radial nerve palsy after fracture of the humerus shaft is 11.8% and commonly occurs following fractures of the middle and middle-distal parts of the shaft ¹². Use of high-resolution ultrasound in cases of post-traumatic radial nerve palsy helps in rapid assessment of the nerve throughout its course and helps in identifying the exact site and cause of palsy ¹. Ultrasound is widely available, less expensive, has no contraindications and can be done at the bed side in cases of trauma. The nerve is easily identified in its short axis in the distal upper arm where it lies between the brachialis and brachioradialis and then traced proximally and distally. The pathological segment of the nerve is identified by decreased echogenicity, change in calibre, loss of continuity or impingement by or entrapment in the fracture segment.

Figure 6. Radial nerve palsy

Footnote: Typical posture of the upper limb in right radial nerve palsy of the newborn. The patient shows a wrist drop and an inability to extend the thumb and metacarpophalangeal joints of the fingers (A), active external rotation of the right shoulder, which is universally seen in radial nerve palsy of the newborn (B), and intact flexion of the right elbow (C).

Radial nerve injury causes

Damage to one nerve group, such as the radial nerve, is called mononeuropathy. Mononeuropathy means there is damage to a single nerve. Diseases affecting the entire body (systemic disorders) can also cause isolated nerve damage.

Causes of radial nerve palsy are manifold with fracture of the humerus shaft being the commonest association. It can occur due to entrapment of the nerve at anatomical sites, entrapment within scar tissue, pressure by tourniquet, under-arm crutches, healing callus, etc. Iatrogenic radial nerve palsy is another common cause of injury which can occur after fracture reduction or after operative management of fracture of the humerus or radius. Elbow surgeries like arthroplasty, radial head fracture repair, synovectomy can cause posterior interosseous nerve palsy. Penetrating injuries like gun shot injuries, animal bites, sharp objects, and intramuscular injections can cause direct insult to the nerve. Thermal and burn injuries are another cause of radial nerve palsy which may also include other nerves in the region of the burn. Systemic demyelinating diseases, lead poisoning or neurotoxic drugs may affect the radial nerve along with other peripheral nerves.

Tumor and tumor-like lesions involving the radial nerve include eripheral nerve sheath tumours, fibrolipomatous hypertrophy, intraneural lipomas, intraneural ganglion, true neuromas and pseudo neuromas ¹⁴.

Causes of radial nerve mononeuropathy include:

• An illness in the whole body that damages a single nerve
• Post-traumatic radial nerve palsy
• Direct injury to the radial nerve
• Penetrating trauma to the arm
• Long-term pressure on the radial nerve
• Pressure on the radial nerve caused by swelling or injury of nearby body structures
• Iatrogenic causes of radial nerve palsy may be manifold. Immediate post-operative wrist drop may be due to direct injury to the nerve, local hematoma causing compression, implant abutting the nerve or due to ‘tourniquet palsy’ or residual block.
• Peripheral nerve sheath tumours include neurofibroma and schwannoma and may be benign or malignant.

Radial neuropathy occurs when there is damage to the radial nerve, which travels down the arm and controls:

• Movement of the triceps muscle at the back of the upper arm
• Ability to bend the wrist and fingers backward
• Movement and sensation of the wrist and hand

When damage destroys the radial nerve covering (myelin sheath) or part of the radial nerve itself, nerve signaling is slowed or prevented.

Damage to the radial nerve can be caused by:

• Broken arm bone and other injury
• Diabetes
• Improper use of crutches
• Lead poisoning
• Long-term or repeated constriction of the wrist (for example, from wearing a tight watch strap)
• Long-term pressure on the nerve, usually caused by swelling or injury of nearby body structures
• Pressure to the upper arm from arm positions during sleep or coma

In some cases, no cause can be found.

Radial nerve injury symptoms

Radial nerve injury symptoms may include any of the following:

• Abnormal sensations in the back and thumb side of the hand, or in the thumb, 2nd, and 3rd fingers
• Weakness, loss of coordination of the fingers
• Problem straightening the arm at the elbow
• Problem bending the hand back at the wrist, or holding the hand
• Pain, numbness, decreased sensation, tingling, or burning sensation in the areas controlled by the nerve

Patients with radial neuropathy can present either with motor dysfunction or sensory symptoms only. Pain over the lateral aspect of the arm extending up to the wrist is the most common complaint in cases of radial tunnel syndrome ¹⁵. Injury to the radial nerve high up in the arm can result in complete loss of extensor function while injuries distal to the supply of triceps brachii spares its function. Fracture of the humerus shaft can result in wrist drop as injury to the nerve usually occurs in the spiral groove or in the mid-arm ¹⁰. The patients will also have loss of sensation over the lateral aspect of arm, forearm, thenar eminence and radial three and a half digits.

Compression of the superficial branch causes paralysis of the extensor carpi ulnaris, extensor digiti quinti and extensor digitorum communis, while compression of the posterior interosseous nerve causes paralysis of the abductor pollicis longus, extensor pollicis brevis, extensor pollicis longus and extensor indicis proprius. Function of the extensor carpi radialis longus is spared as the fibres arise more proximally from the main branch of the radial nerve. This results in finger drop with deviation of the wrist to the radial aspect which is the classical presentation in cases of posterior interosseous nerve palsy. Wartenburg syndrome is entrapment of the superficial branch at the distal radius and presents with pain and numbness in the posterior part of the thumb ¹⁶.

Patients with peripheral nerve sheath tumours may present with visible swelling with no motor or sensory deficit.

Clinical examination and electrodiagnostic studies (nerve conduction velocity and electromyography [EMG]) have been the mainstays of diagnosis in neuropathies as they provide essential information about the type of dysfunction and help in clinical monitoring. EMG may not be positive for 3–6 weeks following injury. Tinel’s sign helps in assessing the possible site of injury and helps in assessment of improvement over time. Nerve injuries were classified by Seddon in 1943 and expanded by Sunderland in 1951. Mackinnon and Dellon in 1992 added grade 6 injury to Sunderland’s grading scheme and defined it as a mixed type of injury which denotes various types of injuries across the cross section of the nerve ¹⁷. Table 1 below illustrates this classification along with imaging findings in different types of nerve injuries.

Radial nerve injury possible complications

Radial nerve injury complications may include:

• Mild to severe deformity of the hand
• Partial or complete loss of feeling in the hand
• Partial or complete loss of wrist or hand movement
• Recurrent or unnoticed injury to the hand

Radial nerve injury diagnosis

Your doctor will examine you and ask about your symptoms and medical history. You may be asked what you were doing before the symptoms started.

Tests that may be needed include:

• Blood tests
• Imaging tests to view the nerve and nearby structures
• Electromyography (EMG) to check the health of the radial nerve and the muscles it controls
• Nerve biopsy to examine a piece of nerve tissue (rarely needed)
• Nerve conduction tests to check how fast nerve signals travel

Radial nerve injury treatment

The goal of treatment is to allow you to use the hand and arm as much as possible. Your doctor will find and treat the cause, if possible. Sometimes, no treatment is needed and you will get better on your own.

If there is a mechanical cause such as a bone spur or compression, then surgery may be helpful. The timing of surgery when radial nerve palsy is due to a humeral fracture is not yet known ¹⁸. Some surgeons wait a few months to see if spontaneous recovery occurs before undertaking explorative surgery. In the acute setting of humeral shaft fracture, proper immobilization of the wrist is necessary. This immobilization can be made possible with a modified coaptation splint ¹⁹. Surgical exploration of the radial nerve is appropriate if the radial nerve palsy occurs during splint application and does not resolve with removal of the splint. Approximately 70% of radial nerve palsy cases have been reported to be resolved with conservative treatment. In the case of immunologically mediated wrist drop, as in mixed cryoglobulinemia, drugs such as rituximab may facilitate a rather rapid recovery ²⁰.

If medicines are needed, they may include:

• Over-the-counter or prescription pain medicines
• Corticosteroid injections around the nerve to reduce swelling and pressure

Your doctor will likely suggest self-care measures. These may include:

• A supportive splint at either the wrist or elbow to help prevent further injury and relieve the symptoms. You may need to wear it all day and night, or only at night.
• An elbow pad of the radial nerve is injured at the elbow. Also, avoid bumping or leaning on the elbow.
• Physical therapy exercises to help maintain muscle strength in the arm.

Occupational therapy or counseling to suggest changes in the workplace may be needed.

Surgery to relieve pressure on the radial nerve may help if the symptoms get worse, or if there is proof that part of the nerve is wasting away.

Figure 7. Radial nerve palsy splint (modified coaptation splint)

Footnote: Coaptation splinting is the standard of treatment for acute humeral 28 shaft fractures in the emergency department. A and B, Coaptation portion of the splint is applied first starting fromunder the axilla to the top of the shoulder. C and D, The intrinsic plus component is placedwith careful attention
paid to wrist extension.

Figure 8. Radial nerve palsy splint (modified coaptation splint continued)

Footnote: The proper molds are applied. A, Valgus mold to prevent healing of humeral shaft fracture in varus. B, Intrinsic plus splint with wrist in extension to prevent wrist drop.

Figure 9. Radial nerve palsy splint (modified coaptation splint – final position)

Radial nerve injury prognosis

If the cause of the radial nerve injury can be found and successfully treated, there is a good chance that you will fully recover. In some cases, there may be partial or complete loss of movement or sensation. Factors that may affect results after radial nerve repair include age, the type of wound and nerve, and location of the injury. Although radial nerve injuries may create lasting problems, proper treatment helps patients return to more normal function.

Radial nerve entrapment

Radial nerve entrapment is an uncommon condition caused by the compression or entrapment of the radial nerve that can occur at any location within the course of the radial nerve distribution, but the most frequent location of radial nerve entrapment occurs in the proximal forearm. This most common location is typically in proximity to the supinator and often will involve the posterior interosseous nerve branch. Depending on the location of radial nerve entrapment a patient may experience pain, numbness, weakness, and overall dysfunction or any combination of these ²². Radial nerve entrapment is uncommon and often under-recognized. The annual incidence rate of the posterior interosseous nerve compression is estimated to be 0.03% while the rate for superficial radial nerve compression is 0.003% ²³.

Radial nerve entrapment is typically a result of radial nerve injury secondary to compression, traction, or direct trauma causing a process of local swelling, edema, or even partial or complete laceration. The compression and/or traction often occur secondary to repetitive motions causing inflammation or architectural changes to the surrounding tissue. There are varying degrees of radial nerve damage severity. In mild cases, the compression of the radial nerve causes no permanent damage to the nerve and nerve sheath fully recover. More severe cases can cause permanent damage to the radial nerve and/or nerve sheath causing persistent deficits.

Figure 10. Radial nerve entrapment

Footnote: Radial nerve entrapment in local scar tissue at the site of chronic inflammation in a case of malunited supracondylar fracture of the humerus. (a) Hypoechoic radial nerve (point A and B) is seen entrapped within mixed echogenic chronic inflammatory soft tissue (5 point and 6 point star). Malunited fracture of humerus can be seen adjacent to it (arrowheads). (b) Long axis view of hypoechoic radial nerve (point A and B) seen entering into the chronic inflammatory tissue. There was no evidence of increased vascularity of the nerve. (c) Plain radiograph showing malunited, displaced fragment of supracondylar fracture of humerus. (d) Axial proton density sequence showing hyperintense radial nerve (black arrowhead) with surrounding hyperintense muscle oedema. (e) Sagittal proton density sequence showing heterogeneously hyperintense area of chronic inflammation in region of malunited supracondylar fracture of humerus (white arrowhead). The radial nerve is enlarged and hyperintense (black arrowhead) and is not visualised within the area of chronic inflammation and surrounding muscle oedema (6 point star) due to similar signal intensities.

Radial nerve entrapment causes

Radial nerve entrapment is often thought to be a result of overuse but can certainly occur secondary to other causes such as direct trauma, fractures, lacerations, compressive devices, or post-surgical changes ²⁴. The radial nerve divides into the superficial radial and posterior interosseous nerves at the level of the radiocapitellar joint. The posterior interosseous nerve runs along the radial neck before piercing the supinator muscle, a common site of entrapment. The radial nerve further divides into four terminal branches that can typically be compressed at one of four other sites as well. These four sites are the fibrous bands around the radial head, the recurrent radial vessels, the arcade of Frohse, and/or the tendinous margin of the extensor carpi radialis brevis. Overuse actions and exercises that can lead to radial nerve entrapment are often repetitive pronation and supination of the wrist and forearm and commonly occur in the locations discussed previously ²⁵.

Multiple classification system exist to categorize radial nerve injury grading. A popular one is the Sunderland Classification which is detailed as follows ²⁴:

1. 1st degree
   • Mild neurapraxia (traction/compression)
   • At most in early/low grade nerve injuries, the myelin sheath is compromised
2. 2nd degree
   • Only the myelin sheath and axon are injured or disrupted
3. 3rd degree
   • Injury with endoneurial scarring; all components of the peripheral nerve are injured except the perineurium and epineurium
   • Most variable degree of ultimate recovery
4. 4th degree
   • Nerve in continuity but at the level of injury there is complete scarring across the nerve, only the epineurium remains intact
5. 5th degree
   • Included within Seddon’s neurotmesis

Correlating Sunderland and Seddon’s classification systems with one another:

• Seddon first degree neurapraxia is the same as Sunderland 1st degree injury
• Seddon second degree axonotmesis is the same as Sunderland 2nd degree injury
• Seddon third degree neurotmesis injuries span Sunderland 3rd, 4th, and 5th degree injuries

Table 1. Correlation between Seddon’s & Sunderland’s classification of nerve injury with imaging findings

Radial nerve entrapment symptoms

Radial nerve entrapment presentation can certainly vary given multiple areas of possible entrapment. Symptoms are usually very slow developing. The duration of symptoms often averages multiple years before a definitive diagnosis is made ²⁴. Symptoms of radial nerve entrapment are pain, sensory and motor changes, paresthesias, and/or paralysis.

Physical exam and/or history often reveal symptoms limited to the dorsoradial aspect of the distal forearm and hand. Findings of decreased sensation over the dorsoradial aspect of the forearm or hand are helpful in establishing the diagnosis. A positive Tinel sign along the radial aspect of the mid forearm is suggestive of this process. Wrist flexion, ulnar deviation, and pronation place strain on the nerve and will often reproduce or exacerbate symptoms. Resisted extension of the middle finger with the elbow extended is another sign of nerve entrapment. This sign is often used to aid in the diagnosis of lateral epicondylitis but it also often positive in cases of radial nerve entrapment.

Radial nerve entrapment complications

Most complications are related to surgery and include:

• Stretching of the radial nerve
• Severing of the radial nerve
• Incomplete release
• Muscle atrophy

Radial nerve entrapment diagnosis

• If radial nerve entrapment is suspected, radiography should be performed to detect or rule out a fracture, healing callus, or tumor as the cause of radial nerve entrapment.
• Ultrasonography can often provide reliable visualization of injured nerves. Axonal swelling, hypoechogenicity of the nerve, loss of continuity of a nerve bundle, formation of a neuroma, and/or partial laceration of a nerve can all be visualized which may aid in diagnosis.
• Magnetic resonance imaging (MRI) can be useful in detecting more subtle causes not found on radiographs or ultrasound such as small tumors, masses, aneurysms, or a compressive synovitis. MRI can also at times detect nerve changes during acute radial nerve entrapments.
• A diagnostic nerve block to help define the distribution of pathology and presentation is considered in some situations.
• Electromyography (EMG)/nerve conduction studies can also be considered but are inconsistent and should only be considered if surgery is a possibility.
• No standard laboratory work is necessary for establishing the diagnosis ²⁶.

Radial nerve entrapment treatment

The acute management of radial nerve entrapment is surgical ²⁴. However, once the surgery is completed, the patient needs to be followed by a neurologist, hand surgeon, physical and occupational therapist. After the healing is complete, most patients require extensive rehabilitation to recover motor and sensory function. In addition, the patient must wear protective splints to protect the hand. Recovery often takes months, and compliance with the exercise program is key ²⁷.

First and Second Degree Radial Nerve Injuries

• Most patients respond and recover after several months — recommended management consists of serial exams and serial electromyography (EMG)/nerve conduction studies testing
• Most patients respond well to conservative therapy. Consider removing any restrictive or compressive devices that are routinely worn. Consider relative rest from offending activity such as limiting repetitive pronation, supination, wrist flexion, and ulnar deviation. Often nerve glide exercises as part of occupation/physical therapy are performed in conjunction with rest and activity modification. If symptoms do not resolve with cessation of activity and rest, then consider splinting.
• If an area of pathology indicates possible compression and can be visualized on ultrasound, providers can consider ultrasound guided hydrodissection to free the compressed portion of the nerve.
• Oral or topical NSAIDs can be used for pain. Steroid and an anesthetic combination can be injected into the point of maximal tenderness for symptomatic relief. The steroid may help decrease any inflammation contributing to the process.
• In the setting of suspected mild degrees of nerve injury, but either prolonged, absent, or delayed evidence of recovery of nerve function both clinically and by serial electromyography (EMG)/nerve conduction study testing, surgery should be the last option if this process has become chronic and conservative treatment has failed after six to 12 months ²⁸.

Third Degree Radial Nerve Injuries (Neurotmesis)

• Acutely, direct surgical repair of the partial versus complete nerve laceration
• Nerve grafting techniques are employed in the setting of lacerations with retractions; often this can present in the subacute setting after injury
• Residual defects or “injury gap” measuring >2.5cm are recommended for nerve grafting techniques
  • Autograft options include the sural or saphenous nerves
    • There is no documented improved functional recovery or outcome when comparing autograft versus allograft or nerve conduits

Radial nerve entrapment prognosis

The prognosis after radial nerve entrapment depend on the severity of the injury. For those with neuropraxic injury, the outcome is good in most cases. For those with axonotmesis, recovery depends on the completeness of release. Unfortunately, many patients have residual deficits. Following neurotmesis, recovery is usually limited even with surgical repair. All patients need extended physical and occupational therapy, and recovery can take months or even years ²⁹.

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