Extensor Mechanism Injuries

The extensor mechanism comprises of the quadriceps muscles and tendon, medial and lateral retinacula, patella, patellar tendon, and tibial tubercle. Tendons of the extensor mechanism are extremely resistant to tensile loads and do not rupture under normal physiologic conditions, even with significant degrees of stress. Injury generally happens due to sudden vigorous contraction of the muscle with the knee in a flexed position, laceration, or a direct impact. Disruption may occur at any level from the quadriceps muscle to the insertion on the tibial tubercle. 

Rupture of the quadriceps tendon usually occurs at or just proximal to the patellar inser- tion. Occasionally the rupture may extend into the vastus intermedius tendon or transversely into the retinaculum. Most patellar tendon ruptures occur at the site of origin on the inferior pole of the patella.

Quadriceps tendon rupture > 40 years 

Patellar tendon rupture < 40 years

Risk Factors for Extensor Mechanism Injuries - Chronic systemic conditions, including rheumatoid arthritis, gout, systemic lupus erythematosus, hyperparathyroidism, and iatrogenic immunosuppression in organ transplant recipients, use of steroids/fluoroquinolones. 

Patients with delayed diagnosis of patellar tendon rupture may experience significant retraction of the patella proximally and subsequent development of quadriceps contractures or adhesions. 

Clinical Features. Clinical evaluation can elicit the correct diagnosis in most cases of complete disruption. Classical signs are:
1. Acute onset of pain, swelling, and ecchymoses over the anterior aspect of the knee and a palpable defect in the patella, quadriceps tendon, or patella tendon
2. Loss or limitation of ability for active leg extension - extension lag usually is seen when the last 10 degrees of extension is performed haltingly or with difficulty)
3. High- riding patella (patella alta) with patellar tendon rupture and superior retraction
4. Low-riding patella (patella baja) with quadriceps tendon rupture and inferior retraction. 

Partial disruptions may not show these clinical signs and may require MRI for confirmation.

Diagnostic Imaging
AP and Lateral X Rays Knee

• Obliteration of the quadriceps or patella tendon, a poorly defined suprapatellar or infrapatellar soft tissue mass (represents proximal or distal retraction of the torn tendon), soft tissue calcific densities (represent avulsed bone fragments of the patella or tibial tubercle), or a displaced patella.
• Patella alta may be sought on the lateral radiograph using a ratio of patellar length to patellar tendon length (the Insall-Salvati ratio). The Insall-Salvati ratio (TL/PL) is considered normal between 0.8 and 1.2. Patella baja: <0.8, patella alta: >1.2. 

Ultrasound has low sensitivity and specificity in diagnosing acute quadriceps and patellar tendon ruptures. MRI shows the entire extensor mechanism and is the best imaging modality for diagnosing pathology in this system, even in the acute phase. MRI usually is reserved for patients with possible incomplete disruption or for those with a complication of intra-articular derangements. 

Management

Early Repair - within 2 to 6 weeks of the initial injury. If the tear is only partial, immobilization with the knee in full extension for 4 to 6 weeks is the treatment of choice. Surgical intervention is required for reattachment of complete tendon ruptures, and repair should be performed as soon as possible. After primary repair, the knee is immobilized in full extension with a long leg cast until healing is complete. Gradually progressive active and passive range-of-motion exercises are indicated for optimal results.

Posted by:

              

     Lakshay Chanana

     

     ST4 Trainee

     Royal Infirmary of Edinburgh

     Department of Emergency Medicine

     Edinburgh

     Scotland

     @EMDidactic

Lisfranc injuries

The Lisfranc joint complex is composed of the bones and ligaments that connect the midfoot to the five metatarsals of the forefoot and Lisfranc ligament connects the base of the second metatarsal to the lateral aspect of the medial cuneiform providing stability to the joint, despite the absence of a ligamentous connection between the first and second metatarsal. 

Lisfranc injuries are a spectrum of injuries which typically occur when an axial load is applied to a plantar-flexed foot. The severity of injury may range from a simple sprain to complete disruption of the tarso-metatarsal joints in the midfoot. These injuries are easy to miss (often diagnosed as a sprain in EDs) because they are rare and often show only subtle or no x-ray findings (1/5 have normal X rays). 

It is important for emergency physicians to be aware of the anatomy of Lisfranc joint complex and have a high index of suspicion for this injury since missed injuries result in long-term misalignment and functional weight-bearing difficulties. 


Clinical Presentation

• Patients are typically unable to weight bear
• Hematoma/ecchymosis on the plantar aspect of the foot
• Significant dorsal midfoot swelling
• Signs of compartment syndrome
• Tenderness to palpation over the midfoot
• Tenderness on twisting the forefoot after stabilising the heel
• Exacerbation of pain with dorsal and plantar flexion of each digit 
• Exacerbation of pain when walking on tiptoes 
• Fleck sign - Small chip fracture from medial margin of the base of M2

Diagnosis

Normal findings on Ankle X Rays:

• On the AP view, the medial edge of the base of the second metatarsal should line up with the medial edge of the middle cuneiform
• The gap between the second metatarsal and medial cuneiform is <2 mm.
• On the oblique view, the medial edge of the third and fourth metatarsal should line up with the medial edges of the middle cuneiform and cuboid, respectively.1
• On the lateral view, the superior border of the first metatarsal should align with the superior border of the medial cuneiform 
• Look for widening between the bases of the 1st and 2nd or 2nd and 3rdmetatarsal bases. Widening >2mm is an indication for urgent surgical intervention

On the AP view (left), the medial edge of the base of the second metatarsal should line up with the medial edge of the middle cuneiform. On the oblique view (right), the medial edge of the third and fourth metatarsal should line up with the medial edges of the middle cuneiform and cuboid, respectively.

Superior border of the first metatarsal aligns with the superior border of the medial cuneiform 

Note widening between medical cuneiform and second metatarsal. Fleck sign - Small chip fracture from medial margin of the base of the second metatarsal

With high suspicion of Lisfranc injury but normal initial X Rays, obtain a30-degree oblique x-rays or do a CT of the foot. 

ED Management

Stable dislocation/fracture injuries are defined as having less than 2 mm of displacement between the first metatarsal and medial cuneiform. These can be managed non-operatively with reduction and casting. The patient should be placed in a non-weight-bearing below-the-knee cast for six weeks and have an outpatient orthopedic follow-up in 2 weeks.  Discharge instruction should include elevation of the leg and warning signs of compartment syndrome of the foot.

For unstable fractures and dislocations ((>2mm widening at the Lisfranc joint), immediate orthopedic consultation is needed for surgical intervention with internal fixation.

Posted by:

              

     Lakshay Chanana

     

     ST4 Trainee

     Royal Infirmary of Edinburgh

     Department of Emergency Medicine

     Edinburgh

     Scotland

     @EMDidactic

Facial Trauma Exam

Thorough MaxilloFacial exams are often necessary during secondary survey in EDs to convey the findings to the Facial surgeons/Ophthalmology. Things you should worrk about is vision, eye muscle entrapment and maxilla/mandible fractures. Ask these three questions to start with and check all the orifices in and around the face. 


Key Questions:

• Is your vision okay?
• Do you feel numb on your face?
• Is your bite okay?

Rule out any ABC compromise first including Cervical Spine injury. 

Head and Neck
External evidence of head trauma
Neck injuries - wounds, swellings

FACE
Look
Watch from front, top and sides
Swelling/Deformity 
Obvious bleeding sites - lacs, avulsed wounds, bruising

Feel
Palpate entire facial bones
Assess TMJ
Surgical Emphysema
Facial Sensations

Move
Mouth opening
Check dental occlusion (Bite)
Bimanual facial exam to assess LeForte Fractures

Check all facial orifices:
Eyes - VA, Pupils, EOM, Visual Fields, Slit Lamp, IOP, Fundus, Intercanthal distance
Ears - TMJ Tenderness, Hemotympanum, Ottorhea, Auricular Hematoma
Nose - Septal Hematoma, Bleeding, Deformity
Mouth - Intraoral lacs, tooth fractures, salivary gland duct site lacs, dentoalveolar fractures

Posted by:

              

     Lakshay Chanana

     

     ST4 Trainee

     Royal Infirmary of Edinburgh

     Department of Emergency Medicine

     Edinburgh

     Scotland

     @EMDidactic

Greenstick and Torus fractures

Torus Fractures (Buckle/Cortical Fractures)

Torus fracture is an injury of the cortex on the non-compressive side of the bone with an intact cortex on the tension side. Torus is derived from Latin (tori) meaning a swelling or protuberance. Deformity should not occur in torus fracture because the periosteum and cortex are intact on the side of the bone opposite to fracture. The distal end of the radius is the most common site for a torus fracture. Compressive forces often result in a bulging or buckling of the periosteum rather than a more complete fracture line. these injuries usually involve the metaphysis. A simple torus fracture will not produce a visible deformity to the shape of the extremity; however, there is typically soft tissue swelling and point tenderness over the bony injury. 

Radiographically, the torus fracture may be subtle. Carefully inspect the contour of the metaphyseal flare. Any asymmetry, bulging, or deviation of the cortical margin indicates a torus fracture. Soft tissue swelling is also usually evident. Torus fractures are not associated with angulation, displacement, or rotational abnormalities, so reduction is not necessary. Treat by splinting in a position of function fracture clinic follow-up within 1 week. 

https://radiopaedia.org/cases/torus-fracture-1

Greenstick Fractures
A greenstick fracture is characterized by cortical disruption and periosteal tearing on the convex side of the bone, with an intact periosteum on the concave side of the fracture. Greenstick fractures are more stable and somewhat less painful than complete fractures because the area of intact periosteum limits bony displacement. The need for reduction is determined by the degree of angulation of the fracture, the age of the child, and the anatomic location of the injury.

https://radiopaedia.org/cases/radius-and-ulna-greenstick-fractures

Posted by:

              

     Lakshay Chanana

     

     Speciality Doctor

     Northwick Park Hospital

     Department of Emergency Medicine

     England

     @EMDidactic

Paediatric Head Trauma

Head injury in a common presentation in children and 0 to 4 years of age is the most commonly affected group. The vast majority of head trauma is caused by blunt force (assaults, abuse, Non-Accidental Injury). t is estimated that only about 5% have an intracranial injury, and <1% of those with intracranial injury require surgical intervention. Clinically significant injuries are rare in children and thus it is a challenge to conclude who needs imaging. Head injuries resulting in a GCS score of ≤8 are severe, those with scores of 9 to 13 are moderate, and those with scores of 14 or 15 are mild. 

Head Injury Pattern in children

• In children, diffuse injuries are proportionally more common whereas, in adults, focal injuries such as epidural and subdural hematomas and cerebral contusions are more common.
• Compared to adults, skull fractures in children are more common but less frequently associated with underlying brain injury.
• A growing fracture can present months on the injury and requires neurosurgical repair.  It can occur when the leptomeninges are torn beneath the fracture, leading to a CSF leptomeningeal cyst that forces apart the fracture edges and leads to nonunion. Growing skull fractures typically present weeks to months following an injury resulting in skull fracture. 

Specific Injuries 
Epidural hematoma - Collection of blood between the inner skull and the dura. Usually results from rapid arterial bleeding from the middle meningeal artery or the dural or diploic vasculature. Generally good prognosis if surgical evacuation can be done in a timely fashion. 

Subdural hematomas - More common than epidural hematomas in children. Bleeding results from the tearing of the subdural veins. These injuries are frequently associated with underlying brain injury and have a worse prognosis. 

Subarachnoid hemorrhage - Often associated with significant trauma and diffuse axonal injury (DAI). Children with DAI present with a depressed level of consciousness with a normal appearing CT scan. 

Cerebral contusions are located in the cortex underlying the area of direct impact (coup lesions) or on the opposite side (contrecoup lesions). 

History and Physical
Mechanism, Time of the incident
Any Witness
LOC, seizure, changes in behavior, or vomiting, ENT Bleed
Medications, Previous Head trauma
Suspect NAI if the history is incompatible with the child’s age 

Particularly in the young child, symptoms of neurologic injury may be subtle. Lethargy, irritability, seizures, and alterations in muscle tone or level of consciousness, as well as vomiting, poor feeding, breathing abnormalities and apnea, raise the suspicion of significant head injury.

Assessment

• ABCs
• GCS
• Pupils
• Head - Inspect, Palpate, Check Fontanelles 
• ENT Exam
• Maxillofacial Exam
• Neck exam 
• Quick Head to toe exam

The big question is about when to image and when to observe? Most of us are minimalists when it comes to imaging in children as ionizing radiation is a long-term carcinogen. 

There are several clinical decisions rules have been developed to guide imaging. 

1. CHALICE (Children’s Head Injury Algorithm for the Prediction of Important Clinical Events)
2. CATCH (Canadian Assessment of Tomography for Childhood Head Injury)
3. PECARN (Pediatric Emergency Care Applied Research Network)
4. NICE guidelines 

PECARN is considered the “best for children and infants, with the largest cohort, highest sensitivity and acceptable specificity of clinically significant  injury

Take Home:

Head injuries requiring surgical intervention are rare in children. Most of them need reassurance and good discharge advise. Be mindful of the various clinical decision rules for risk stratification. 

Posted by:

              

     Lakshay Chanana

     

     Speciality Doctor

     Northwick Park Hospital

     Department of Emergency Medicine

     England

     @EMDidactic

Sternoclavicular joint Injuries

Sternoclavicular joint is an  extremely stable joint, due to the strong surrounding ligaments, and thus fracture/dislocations are rare and most injuries simple sprains. Significant forces are required to disrupt the strong ligamentous stabilizers of this joint. The most common causes are MVCs and injuries sustained in contact sports.

 The joint may be anteriorly or posteriorly dislocated.

www.anatomyzone.com

Grading on Injury
Injuries to the SCJ can be graded into three types. A grade I injury is a mild sprain secondary to stretching of the sterno-clavicular and costoclavicular ligaments. A grade II injury is associated with subluxation of the joint (anterior or posterior) secondary to rupture of the sternoclavicular ligament. The costoclavicular ligament remains intact. Complete rupture of the sternoclavicular and costoclavicular ligaments results in a grade III injury (dislocation).

Minor trauma may result in a sprain are treated with with ice, sling, and analgesics and follow up with Orthopaedics. 

Anterior and Posterior Dislocation
Results from a direct blow to the shoulder, causing the shoulder to roll forward. Patients present with severe pain which is exacerbated by arm movement and lying supine. The pain will be exacerbated by lateral shoulder compression, arm movements, deep breathing or coughing.The shoulder may appear shortened and rolled forward. 

http://msk-anatomy.blogspot.co.uk/2012/06/sternoclavicular-joint.html

On examination, anterior dislocations have a prominent medial clavicle end that is visible and palpable anterior to the sternum while in posterior dislocations, the medial clavicle end is less visible and often not palpable, and the patient may have signs and symptoms of impingement of the superior mediastinal contents, such as stridor, dysphagia, and shortness of breath. 

Imaging
CXR is needed to exclude a injuries such as a  pneumothorax, pneumomediastinum, and hemopneumothorax. Routine radiographs have a low sensitivity for the detection of dislocation and thus special views and comparison with the other clavicle may be required. CT remains the imaging procedure of choice and is recommended especially in any posterior dislocation with concern for injury to the mediastinal structures. 

Management

Anterior Dislocation

Patients with uncomplicated anterior dislocations may be discharged without an attempted reduction. Look for concomitant Glenohumeral and Acromioclavicular joint injuries. Clavicular splinting, ice, analgesics, sling, and orthopedic referral are required.

Closed reduction may be performed within 10 days of the injury by placing the patient supine with a towel rollin between the shoulder blades. The arm is then abducted to 90 degrees and longitudinal traction is applied with slight extension by moving the arm toward the ground, and pressure is placed over the medial end of the clavicle. The application of direct pressure over the medial end of the clavicle may also reduce the joint. Post reduction, the patient should be placed in a figure of * brace for 4-6 weeks. Despite successful reduction, the joint is usually remains unstable and redislocates in half of the cases.

The use of acute reduction of anterior dislocations is controversial as most end up redislocating and reduction techniques risk injury to mediastinal structures.

Posterior Dislocation

Posterior dislocations may be associated with life-threatening injuries to adjacent structures, including pneumothorax or injury to surrounding great vessels, trachea, or oesophagus.  Orthopedic consultation is necessary for closed or open reduction. Open reduction should be performed in the operating room.

Take Home

• Posterior dislocations necessitate prompt orthopaedic referral and looking for evidence of compression of retrosternal structures.
• Anterior dislocations often remains unstable post treatment and thus acute reduction is debatable. 

Further Reading:

• Rosen's Emergency Medicine - 7th Edition
• TIntinalli's Emergency Medicine - 8th Edition
• LIFTL
• ALiEM
• Morell, D. J., & Thyagarajan, D. S. (2016). Sternoclavicular joint dislocation and its management: A review of the literature. World Journal of Orthopedics, 7(4), 244–250. http://doi.org/10.5312/wjo.v7.i4.244

Posted by:

              

     Lakshay Chanana

     

     Speciality Doctor

     Northwick Park Hospital

     Department of Emergency Medicine

     England

     @EMDidactic