Coronoid Fracture

The coronoid process provides anterior buttress against posterior subluxation or displacement. The radial head prevents valgus instability, and the coronoid process prevents varus instability. The coronoid process also provides attachment for the anterior bundle of the MCL and attachment to the anterior capsule. The anterior capsule attaches 6mm distal to the tip of the coronoid process. The anterior bundle of the medial collateral ligament attaches to the sublime tubercle 18mm distal to the tip of the coronoid process. You need to know the difference between the insertion of the MCL and the insertion of the brachialis as seen here. If the fracture of the coronoid process tip is small, the brachialis should insert distal to the tip of the coronoid process. There are two types for the mechanism of injury: posterolateral rotatory displacement and varus and posteromedial rotatory displacement. Posterolateral rotatory displacement is a fracture of the radial head, fracture of the coronoid process tip, and dislocation of the elbow. Varus and posteromedial rotatory displacement are associated with fracture of the anteromedial coronoid process. The LCL tears from the humerus, and the MCL may not be ruptured. In posterior elbow dislocation and posterolateral instability, the lateral side fails first with the medial side failing last. This valgus and supination can result in the terrible triad. Patient with instability after elbow fracture dislocation always has a coronoid fracture, and it can redislocate in a cast or after surgery. Elbow dislocation with Type II coronoid process fracture and non-reconstructable comminuted radial head fracture. Treated by repair of the lateral collateral ligament, do radial head arthroplasty, and do ORIF of the coronoid process. This is an example of the terrible triad (dislocation of the elbow, coronoid fracture, and radial head fracture) and you need to fix all these injuries. Address each injury to restore elbow stability. If you have an elbow dislocation with fracture of the olecranon tip fracture and a radial head fracture, the likely pattern of instability is valgus posterolateral rotatory instability. There will be rupture of the LCL from the humerus and varus force will cause medial facet fracture, and this is the malignant fracture pattern. To recognize the posteromedial facet injury, look at the AP view x-ray in addition to the lateral view x-ray (in the lateral view you may miss it). In large medial coronoid fracture and elbow dislocation, there probably will be varus posteromedial rotatory instability, and it will affect the anteromedial facet of the coronoid. In fracture of the coronoid process, the x-ray is difficult to interpret. The fracture may be mistaken for a radial head fracture. The structures overlap, and we may miss the fracture. In the lateral view radiograph, you find a chip a bone. AP view radiograph will find a nondislocated elbow with an anteromedial coronoid process fracture. if you miss the anteromedial coronoid process fracture, you will get progressive narrowing of the joint space from lateral to medial between the medial trochlea and the coronoid process. This entity (anteromedial facet fracture) that gives posteromedial instability, occurs in conjunction with lateral collateral ligament injury. When you see this fracture, suspect anteromedial coronoid fracture, especially when you cannot find a radial head fracture. You may also find narrowing of the joint space between the medial trochlea and the coronoid process. CT scan is usually very helpful. There are two known classification systems: Regan & Morrey Classification and O’Driscoll Classification. Regan & Morrey Classification is based on viewing the lateral x-ray. In Regan & Morrey Classification, there are three fracture types based on viewing the lateral x-ray. Type I is a shear fracture of the tip of the coronoid process. Type II involves up to 50% of the coronoid process. Type III involves more than 50% of the coronoid process. This is a very simple classification system, but the problem is that it does not show the malignant fracture pattern. The O’Driscoll classification is very helpful, and it will show the anteromedial facet fracture that will create posteromedial instability. The O’Driscoll classification can be the tip, anteromedial facet, or basal. The O’Driscoll classification recognized the anteromedial facet fracture caused by varus posteromedial rotatory force. This fracture could be missed on the x-ray and can cause degenerative joint disease.

Scratch Collapse Test

The scratch collapse test is a provocative test for nerve entrapment or compression. This is becoming a popular test, and it is one of many examination techniques used in the diagnosis of nerve compression, entrapment, or injuries. The scratch test is a simple examination test that is similar in sensitivity to other examination tests in the diagnosis of cubital tunnel syndrome and other entrapment areas of the different nerves, such as radial tunnel syndrome, pronator teres syndrome, and other nerve entrapment areas. This test supplements, but does not replace, other information that we collect during obtaining the history and physical examination of the patient. It is really an added, helpful test that will precisely localize the site of nerve compression. Do this test if you need to. Not only can this test add or provide confirmation where entrapment of the nerve is located, but it can also precisely localize the area of the entrapment of the nerve that `is known to have different sites of entrapment, such as the ulnar nerve. If the patient has a nerve entrapment at a specific site, after the scratch, the patient will temporarily lose the ability to resist the internal rotation force to their arm. The arm will collapse in the direction of internal rotation. The mechanism is unknown, and it could be a reflex response. Because after you scratch or stroke the skin above the nerve, the arm seems to have no power, and it collapses as we test the resistance and internally rotate the arm. There might be bias from the examiner due to the subjective evaluation of the brief, temporary loss of resistance or loss of power after the scratch. To perform the test, have the patient standing or sitting with the arms at the sides and the elbows flexed to 90 degrees. Have the fingers and the wrist extended, then the examiner applies force against the patient’s forearm to internally rotate the arm and ask the patient to resist this force. The examiner and the patient will both assess the baseline resistance of the patient. The skin over the potential nerve entrapment area is scratched by the examiner, and then the examiner immediately repeats the test. The change in resistance is assessed. Positive scratch collapse test occurs when the patient has no resistance to the examiners force and the arm collapses in internal rotation. There should be no delays in retesting the patient because it may produce a false negative result. Adding ethyl chloride (the cold spray) will temporarily numb or anesthetize the skin superficial to the nerve of interest. It will freeze out a response to scratching. It also may show secondary areas of compression of the same nerve or different nerves. It also may show secondary areas of compression of the same nerve or different nerves. After you apply the cold freezing spray to the area of interest, the test is repeated. The cold spray should freeze out the response to scratching. If you suspect multiple sites of entrapment, use the freezing spray to numb the area then scratch it, and usually the patient will have strength return after scratching the area. The freezing spray can make the examiner eliminate sites or add sites of entrapment to the differential diagnosis. It could be helpful in identifying multiple areas of compression for the same nerve.

Subtalar Dislocation

When the subtalar dislocation happens, the talonavicular joint also becomes dislocated. There are two types of subtalar dislocations: medial subtalar dislocation and lateral subtalar dislocation. Medial dislocations are 4 times as common as lateral dislocations. Some of these dislocations can be open and urgent reduction is important to decrease skin necrosis and interruption of the circulation of the foot. After either closed or open reduction, the subtalar joint is usually stable. Lateral subtalar dislocation means that the foot goes lateral. As the foot goes lateral, the structure in the medial side becomes trapped. The posterior tibial tendon blocks successful closed reduction of the lateral subtalar dislocation. Lateral subtalar dislocation is a bad type. It is worse than the medial subtalar dislocation and is not as common. The foot goes lateral and as the foot goes lateral, the medial structures get pulled from also trying to go lateral. As you try to reduce the foot to its normal position, then there can be some entrapment, usually the posterior tibial tendon. This tendon will be interposed, and you will be unable to do closed reduction. This lateral subtalar dislocation will have a high incidence of fractures of the surrounding tarsal bones, and the subtalar joint could be unstable after reducing the dislocation. Lateral subtalar dislocations are more open than the medial subtalar dislocations. Open subtalar dislocations have a high incidence of infection. If the patient sustained an open injury to the foot with complete extrusion of the talus, the treatment should be to give the patient antibiotics and debride the wound, clean the talus using betadine solution or normal saline with antibiotics, and after the wound is debrided, implant the talus back into its bed. You may want tot use external fixator after that. The medial subtalar dislocation is different. Rarely the dislocation is irreducible (it usually reduces easily). Irreducible dislocation can be due to: impaction fracture of the head of the talus, interposition of the extensor digitorum brevis tendon (popular in exams), or interposition of the peroneal tendons. In medial subtalar dislocation, the foot appears supinated. In lateral dislocation, the foot appears pronated. The majority of both dislocations can be managed by closed reduction and immobilization, which the closed reduction should be done as soon as possible to decrease the risk of skin complications. Closed reduction is probably difficult in about 5-10% of medial dislocations and 15-20% of lateral dislocations. The dislocation can be reduced easily, and you will get an x-ray to evaluate and see if the dislocation is reduced or not, but you will probably also see it clinically. If you do not have a fracture or any fragments in the post-reduction x-rays, then the success rate with a splint or immobilization cast is very good. The medial dislocation has a better prognosis than the lateral dislocation. In the medial subtalar dislocation, the late instability is rare, and the duration of immobilization should be short (about 3-4 weeks). If you have a lateral subtalar dislocation, you may want to evaluate the foot by CT scan after closed reduction and splinting the patient. The reason that you get a CT scan, is to see if you have any bony fragments that need to be removed or fixed, and that can also be done for the medial subtalar dislocation if you think it is necessary. These bony fragments can cause the subtalar joint to be unstable. The lateral subtalar dislocations are a high energy injury. They are frequently associated with small osteochondral fractures. Larger fragments should be fixed, and a small fragment that is entrapped in the joint should be excised. If you think the joint is unstable after reduction, check for the presence of a large intra-articular fracture and try to reduce it and fix it. You want to start early range of motion, so immobilize the patient for a short period to avoid stiffness but try to avoid the recurrence of the dislocation or the instability. The subtalar dislocations can cause stiffness of the subtalar joint and degenerative arthritis. If you can’t do closed reduction then you need to do open reduction, and you need to know that the extensor digitorum brevis is usually the entrapped in medial subtalar dislocation, and the tibialis posterior is the one that is usually entrapped in the lateral subtalar dislocation.

Lisfranc Dislocation

Lisfranc injury is a tarsometatarsal fracture dislocation that involves the medial cuneiform and the base of the second metatarsal. The severity of the injury can range from a mild sprain to severe dislocation or fracture dislocation. The Lisfranc dislocation can be a purely ligamentous injury, boney injury, or a combination of both. The metatarsals are usually dislocated dorsally and laterally. The condition could be missed and may result in progressive foot deformity, disfunction, chronic pain, and arthritis. The oblique interosseous ligament (Lisfranc ligament) is the strongest ligament. The region is stable because the bony architecture is connected to strong ligaments, especially the Lisfranc ligament. Osseous stability is provided by the roman arch arrangement of the metatarsals, and the Lisfranc ligament stabilizes the 2^nd metatarsal to maintain the midfoot arch. The Lisfranc ligament is between the medial cuneiform and the base of the 2^nd metatarsal. The keystone configuration is formed by the base of the 2^nd metatarsal that fits into the mortise, which is made by the medial cuneiform and the recessed middle cuneiform. The mechanism of injury results from axial loading on a plantar flexed foot. Diagnosis is done by a combination of clinical exam and x-rays. Clinical presentation could show midfoot pain, plantar ecchymosis, and tenderness on the dorsal aspect of the midfoot. When you see that clinical situation, you need to suspect Lisfranc injury even if the x-ray is negative. The fleck sign is a small avulsion fracture at the medial base of the second metatarsal. It represents an avulsion of the Lisfranc ligament. The diastasis between the 1^st and 2^nd metatarsal of more than 2 mm is considered to be a Lisfranc injury. The injury may be subtle and can be missed. You will need to get standing weight bearing x-rays if the injury is suspected (compare the x-ray to the other side). If you purely ligamentous injury, the treatment will be early fusion of the 1^st and 2^nd tarsometatarsal joints. Ligamentous injuries to the tarsometatarsal and intermetatarsal joints resulted in a worse outcome following open reduction and internal fixation than Lisfranc injuries that involve fractures. Ligamentous Lisfranc injuries will give a better result if they are treated by primary arthrodesis. If the Lisfranc injury is treated by open reduction internal fixation, it will result in a higher rate of secondary surgery and a lower function outcome. Anatomic reduction is important if the surgeon selects open reduction and internal fixation. If you do open reduction and internal fixation for a ligamentous injury, the patient may have persistent pain and arthritis. Closed reduction and percutaneous pinning do not give a good result. Post-traumatic arthritis and altered gait is common.

Distal Phalanx Fractures

Injuries of the distal phalanx can be a fingertip injury, which will be a different topic by itself. Fracture of the distal phalanx is the most common phalangeal fracture, and it can occur from a crushing injury that produces major soft tissue injury. It can involve the tuft, the shaft, or the base of the phalanx. If it involves the tuft, then it is usually a crush injury and may be associated with a nail bed injury. Usually it is associated with subungual hematoma. If the hematoma involves more than 25% of the nail, especially if there is a fracture, then you need to remove the nail, as well as explore and suture the nail bed. Most of the time the fracture is comminuted and probably will need a splint. In some cases, the fracture may need k-wire fixation. The fracture may fail to unite. Fracture of the distal phalanx shaft is usually stable and can be treated conservatively by a splint or buddy taping, and surgery is rarely needed. Distal phalanx nonunion, if symptomatic and painful, do reduction and internal fixation with bone graft. With fracture of the distal phalanx base, there are two types jersey finger and mallet finger. The patient that is unable to flex the DIP joint is the patient that has a Jersey finger, or volar base fracture. The patient with a mallet finger, or dorsal base fracture, is unable to extend the DIP joint. If the fracture is large, there may be a volar subluxation of the distal phalanx. Be aware of avulsion fracture at the base of the distal phalanx, because it must be evaluated thoroughly. It could be an avulsion of the insertion of the flexor or the extensor tendon, and the fracture appearing small and benign. If the fragment is large or if there is volar subluxation of the joint, then this can be treated by different techniques. K-wire utilization is a very common technique. The goal is to keep the DIP extended until the bone or the tendon heals. Some orthopaedic surgeons will continue to treat this injury by closed means (splint), even if there is a volar subluxation of the joint. The rationale is that a stiff finger that is treated by closed means is better than a stiff finger that is treated by surgery. When the tendon is avulsed with a bony fragment, the tendon with a piece of bone could be retracted at different levels, and it can be seen in the x-ray. In general, if the tendon is retracted to the palm, then the blood supply could be affected and surgery should be done within 10 days. If the fragment is large, then usually the retraction is limited to the DIP. The finger lies in extension relative to the other fingers, and the patient will not be able to do active DIP flexion. Seymour fracture is an epiphyseal fracture of the distal phalanx. It is a flexion injury that leads to physeal separation between the extensor tendon dorsally and the flexor digitorum profundus volarly. This flexion injury causes an avulsion of the nail from the nail fold with disruption of the nail matrix. The patient’s finger will appear flexed, which looks like a mallet finger, and the nail appears to be larger compared to the nail on the other side. This injury is really an open fracture and needs to be treated by antibiotics, removal of the nail, irrigation and debridement of the fracture, reduction and pinning of the fracture and nail bed repair.

Anatomy of L5 Nerve Root Muscle Innervation

The L5 nerve root is part of the lumbosacral plexus. It is an important component of the sciatic nerve. The L5 nerve root causes ankle dorsiflexion, which also comes from the L4 nerve root. The tibialis anterior is the primary dorsiflexor of the ankle, and the innervation comes from the deep peroneal nerve. Injury of the L5 nerve root can cause weakness of the tibialis anterior muscle, and this can lead to a foot drop. The L5 nerve root also causes dorsiflexion of the toes through innervating the extensor hallucis longus and extensor digitorum longus, and this innervation comes from the deep peroneal nerve. Of particular interest, is the extensor hallucis longus. Weakness of the big toes extension is usually present when disc herniation affects the L5 nerve root. So, when the L5 nerve root is affected, the extensor hallucis longus could become weak. The tibialis posterior is an important muscle that runs behind the medial malleolus, and its innervation comes from the posterior tibial nerve (L4-L5). The function of the tibialis posterior is to invert the foot, to assist in plantar flexion of the ankle, and to maintain the medial longitudinal arch. The L5 nerve root also innervates the muscles that cause hip extension, and the muscles are the hamstrings, which is innervated by the tibial nerve, and the gluteus maximus which is innervated by the inferior gluteal nerve. The hamstring muscles are also a major flexor of the knee. The L5 also innervates the hip abductors (gluteus medius and gluteus minimus), and the innervation comes from the superior gluteal nerve, injury of L5 nerve root can cause weakness of the hip abductors, and this can lead to Trendelenburg Gait. The L5 nerve root is really an important nerve root that supplies a lot of muscles. The L5 nerve root gives sensory innervation to the top of the foot. If you do not remember anything about the L5 nerve root, try to remember that injury to this nerve can cause weakness of the big toe extension, weakness of ankle dorsiflexion (foot drop), and weakness of the hip abductor muscles which will give you Trendelnburg Gait.

Sternoclavicular Joint Injuries

The sternoclavicular joint is composed of the proximal end of the clavicle and the manubrium of the sternum. Sternoclavicular joint injuries are uncommon shoulder injuries. In young patients, the injury is usually a physeal injury. Medial clavicle physeal fracture occurs in a patient less than 25 years old. Th epiphysis ossifies at the age of 18 and closes between 20-25 years of age. Anterior dislocation is more common than posterior dislocation. The AP x-ray is difficult to interpret, and we get what is called the Serendipity view X-ray, which is 40° cephalic tilt view with the beam focused on the manubrium, then you compare both clavicles. The serendipity view allows for identification of the anterior or posterior translation. In practice clinically, the anterior dislocation will be obvious. The posterior dislocation will not be obvious. The patient will have pain, order a CT scan. A CT scan is the best study to evaluate acute, traumatic injuries of the sternoclavicular joint. It will help determine what type of injury or dislocation (anterior or posterior). A Ct scan will show if the injury is a physeal injury or if it is a true dislocation. It shows the status of the mediastinal structures. Anterior dislocation is common. The patient will have pain, a bump, or swelling that is increased by abduction of the arm. Anterior dislocation is unstable if you reduce it, but it is benign. If it is acute, try to reduce it, otherwise accept the deformity. Observe the patient and treat the patient symptomatically. The anterior sternoclavicular dislocation is rarely symptomatic when left unreduced. Most of the time the patient will do very well, and it will not affect function or range of motion (resuming of unrestricted activity in 3 months). If the injury is chronic and symptomatic, then you will do surgery. The type of surgery that is done is a resection of the medial part of the clavicle. Resect less than 15 mm of the medical clavicle. Do soft tissue stabilization of the residual medial clavicle with costoclavicular ligament reconstruction. Reconstruction of the sternoclavicular joint utilizing tendon graft (allograft or autograft can be used). The hamstring tendon technique is popular, and the figure eight technique is commonly used because it provides great stability. The posterior sternoclavicular dislocation is less common and is a true orthopaedic emergency. 1/3 of the posterior dislocations may have compressive effect by exhibiting pressure on the great vessels, esophagus of the trachea. It may cause dyspnea, tachypnea, dysphagia, or paresthesia and it needs reduction. It has minimal, visible clinical findings. Sometimes the affected shoulder is shortened with forward thrust. The posterior sternoclavicular dislocation will be stable after reduction. You will have general anesthesia with thoracic surgeon backup. With a posterior sternoclavicular dislocation start with closed reduction with the hand or with a towel clip and lift the clavicle up. When you do closed reduction, the initial position for the extremity is the same for anterior and posterior dislocation. You will have general anesthesia and you will do abduction and extension of the shoulder. For the posterior dislocation, you will do abduction and extension. There will be a bump underneath the medial scapula. You will manipulate the medial clavicle with a towel clamp or with the fingers, lifting the clavicle up and reducing the joint. The posterior dislocation is usually stable, so give the patient a sling for 3-4 weeks. For the anterior dislocation, you will do direct pressure. If the reduction is stable, you will use a figure 8 strap or sling, and do therapy at 3-4 weeks. If posterior dislocation is unstable or irreducible, you will do reduction or excision of the medial clavicle plus stabilization of the soft tissue. If it is chronic, recurrent, or symptomatic, you will do excision of the medial clavicle plus soft tissue stabilization. Do not try to do closed reduction in late or chronic cases, because there are mediastinal adhesions that may cause problems inside the chest.