Radial Nerve Injury- Locations

radial nerveThe posterior cord of the brachial plexus gives the axillary and radial nerves. Radial nerve compression or injury may occur at any point along the course of the nerve. All motor and sensory function below the axilla will be affected with injury at this level. With injury to the radial nerve at the axilla, there will be loss of function to the triceps and weak elbow extension. The patient will experience wrist drop due tSaturday night palsyo loss of function associated with the extensor carpi radialis longus and extensor carpi radialis brevis muscles. There will also be a loss of finger extension. Put the wrist in extension and ask the patient to extend the fingers. Sensory loss will also be seen in the distribution of the superficial branch of the radial nerve.

Saturday Night Palsy is a common cause of compression or injury to the radial nerve at the axilla. This condition is named due to the position a person may fall asleep in while drinking, with the back of their arm compressed by a chair back, or bar edge, etc. Another common condition is referred to as Honeymoon Palsy, which occurs from another individual sleeping on one’s arm overnight, compressing the nerve. Crutch Palsy occurs from the compression on the nerve from walking with crutches.

radial nerrrrrrveeeeeeAdditionally, there are several compressions or fractures that may cause injury to the radial nerve within the spiral groove. For example, a fracture of the distal third of the humerus may entrap the radial nerve, causing all motor and sensory function below the level of injury to be affected. The radial nerve is vulnerable, usually due to a fracture of the humerus at the spiral groove. Injury may also occur below the spinal groove when there is a fracture in the distal third of the humeral shaft. If a Holstein-Lewis Fracture occurs, injury to the nerve at this level will cause the condition known as wrist drop, as well as weakness of finger extension. Sensory loss will also be seen in the distribution of the superficial branch of the radial nerve.

Entrapment of the posterior interosseous nerve at the “Arcade of Frohse” is a low radial nerve palsy; occurring below the elbow. Motor function below this area will be affected by the injury. The posterior interosseous nerve is purely motor and the patient will have no sensory loss. The Arcade of Frohse is a site of radial nerve entrapment which may cause paralysis of the posterior interosseous nerve. frohse

With injury to the posterior interosseous nerve, the patient will experience difficulty with extension of the fingers only. It is important for the physician to ask the patient to extend the wrist first when examining the finger extension. A Monteggia Fracture, or a fracture of the proximal third of the ulna/radius with dislocation of the radial head may cause compression of the radial nerve secondary to the fracture. A neurovascular examination is important for these fractures. A nerve injury, especially involving the posterior interosseous nerve, is not uncommon (observe). The patient will have a loss of finger extension. Wartenberg’s Syndrome is a compression of the superficial branch of the radial nerve. Pain associated with this condition is located 8cm proximal to the radial styloid; wearing a wristwatch may irritate this area. Pain and paresthesia will be experienced on the dorsum of the hand and the patient will have a positive Tinel’s sign.

wartenburgs point

 

Tillaux Fractures

ankle anat

In adults, ligaments are weaker than bone. The anterior tibiofibular ligament in adults is torn first in the majority of ankle fractures. In children, the growth plate is weaker and can become avulsed. An avulsion injury is rarely seen in adults because the ligament gives out instead of avulsing the bone.

growth plaateTillaux fractures occur in adolescents, usually around 12-15 years of age. These fractures occur after the middle and medial parts of the epiphyseal plate closes and before the lateral part is closed. The lateral part of the growth plate remains open, which could allow for an avulsion fracture at the attachment of the anterior tibiofibular ligament. An external rotating force causes an avulsion of the distal tibial epiphyseal plate anterolaterally. Further lateral rotation displaces the fracture and may be associated with fracture of the lateral malleolus. external rotation

Treatment

If the fracture is displaced 2mm or more, the surgeon will want to perform a reduction and fixation. This fixation can be done from either lateral to medial or medial to lateral. Wagstaffe’s fracture is an avulsion of the anterior portion of the fibula by the anterior tibiofibular ligament. This type of fixationinjury is associated with supination external rotation type injuries (Lauge-Hangen) and typically occurs in adult patients.

 

 

Hamate Fractures

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Fractures of the hamate bone are rare, difficult to diagnose, and routine x-rays may not show the fracture. Hamate fractures are classified as either a hook fracture or as a body fracture.

Hamate hook fractures are usually seen in individuals who participate in sports which involve a racquet, baseball bat, or from swinging a golf club.

Swinging of the golf club may cause a hook fracture of the Hamate bone. Missing the fracture can lead to persistent pain from nonunion.

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Hamate body fractures are associated with axial force trauma, such as a fist striking a hard object, a fall, or from crushing injuries. It may also be accompanied by 4th and 5th metacarpal subluxation. Coronal fractures are the most common type of Hamate body fractures.

There are three types of coronal fractures; Type A (large piece), Type B (moderate piece) and Type C (avulsion). Make sure to watch out for subluxation of the joint due to pull from the Extensor Carpi Ulnaris.

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Hook fractures of the Hamate are best seen by carpal tunnel or supination x-ray views. For hamate fractures, CT scan is the best study. A 30° pronated view is helpful for body fractures.

Clinical Evaluation

Pain will be present, especially with axial loading of the ring and little finger or by grasping an object. The patient will have dismissed grip strength. They may have ulnar and median nerve neuropathy symptoms. The most common findings are pain and tenderness on the ulnar side of the wrist, distal to the wrist joint.

The pull test has been recently described. This is when the palm of the hand is placed into supination, the wrist is in full ulnar deviation, and the fingers of the patient should be flexed. The examiner pulls on the ulnar two digits with the patient resisting the pull. A positive test with pain in the area of the hook indicates a fractures hook of hamate injury. Pain may also be felt due to compression of the ulnar nerve in the Guyon Canal.

Treatment                        

Early immobilization for acute fractures with short arm splint for 6 weeks will be used to avoid a nonunion. For symptomatic nonunion, excision of the fracture fragment will be needed.

Types A and B require open reduction and internal fixation, in addition to stabilization of the joint if needed. Type C requires closed reduction and percutaneous pinning of the fragment for stabilization of the joint. If a closed reduction of the joint is not adequate, open reduction and stabilization of the joint should be done. A displaced fragment with subluxation requires reduction of the joint and stabilization of the joint with K-wires or fixation of the fragment.

When a 4th or 5th carpometacarpal dislocation occurs, one should make special effort to find a coronal fracture of the hamate.

 

 

 

Bone Healing – A Basic Introduction

Dr. Nabil Ebraheim pic
Dr. Nabil Ebraheim
Image: uthealth.utoledo.edu/

As the chair and a professor of the Department of Orthopaedic Surgery at the Medical University of Ohio, Dr. Nabil Ebraheim teaches the diagnosis and operative treatment of diseases and injuries of the musculoskeletal system. Also the director of the university’s orthopaedic trauma fellowship and the author of many peer-reviewed papers, Dr. Nabil Ebraheim pursues a focus on bone healing.

Bone healing is a multiphase process. It begins with inflammation, which occurs when blood flows from the fracture into the surrounding area. As this happens, the tissue swells and the blood forms clots, which create stability at the site. This clotted blood also forms the initial scaffolding for the growth of new bone.

Bone production occurs first with the production of a soft callus. Specialized cells called chondroblasts create this initial repair structure, the building of which can take up to three weeks. Once the soft callus is fully formed, the body activates osteoblast cells to create new bone cells, which form a harder callus.

The final and longest phase of healing is known as bone remodeling. During this phase, which can take a period of three to nine years to complete, the new bone becomes harder and more structurally sound. At the same time, osteoclast cells dissolve the excess bone tissue at the outside of the hard callus, and the bone slowly returns to its original shape.