Flashcards in Orthopaedics - Hand, wrist and elbow Deck (70):
What is the difference between the anatomical and surgical neck of humerus?
The anatomical neck is located on the proximal humerus. It separates the head from the greater and lesser tubercles.
The surgical neck lies below the anatomical neck between the upper end of the humerus and the shaft. Importantly, the axillary nerve and circumflex vessels wind around the surgical neck of the humerus. These are all at risk in shoulder dislocations and humeral neck fractures.
What is the function of the greater and lesser tubercles?
These provide an insertion site for the rotator cuff muscles. They are separated by an intertubercular sulcus or bicipital groove, in which the long head of the biceps runs.
What is the spiral groove?
This is a faint groove located on the posterior aspect of the shaft of the humerus. The medial and lateral heads of triceps originate from either side of this groove and the radial nerve passes between these 2 heads.
What nerve passes behind the medial epicondyle to enter the forearm?
The ulnar nerve winds around the medial epicondyle and passes into the cubital tunnel. It emerges to run between the two heads of flexor carpi ulnaris which it supplies.
What part of the distal humerus does the ulnar and radius articulate with?
At the elbow joint, the trochlear of the humerus articulates with the trochlear notch of the ulnar. The rounded capitulum of the distal humerus articulates with the radial head. The medial border of the trochlear projects a little more inferiorly than the lateral border. This accounts for the carrying angle - i.e. the slight lateral angle made between the arm and forearm when the elbow is extended.
What is the olecranon fossa?
This is a depression on the posterior aspect of the distal humerus, which accommodates the olecranon of the ulnar. It permits flexion and extension movements.
Where does the biceps tendon insert?
The biceps tendon inserts onto the radial tuberosity. Specifically it inserts onto the rough posterior part. The anterior part of the tuberosity is smooth where it is covered by a bursa.
Where are the ulnar and radial heads?
The radial head is located proximally and articulates with the capitulum of the distal humerus. The ulnar head is distal. The ulnar head does not play a part in forming the wrist joint. The trochlear notch on the proximal ulnar articulates with the trochlear at the elbow joint.
How do the radius and ulnar move during pronation and supination movements?
The ulna remains relatively fixed and the radius does all the moving! The radius rotates along the radial notch in the proximal ulnar and the radial shaft pivots around the ulnar. The two are connected by an interosseous membrane. The distal radius rotates around the head of the ulnar.
What type of joint is the elbow joint?
The elbow is a synovial hinge joint (unlike the shoulder which is a ball and socket joint). At the elbow, the humeral capitulum articulates with the head of the radius, and the trochlear of the humerus articulates with the trochlear notch of the ulna.
There are 2 fossae located above the trochlear and capitulum to accomodate the capitulum of the ulna and the radial head respectively, during full flexion.
The elbow joint communicates with the superior radio-ulnar joint.
Where is the elbow joint capsule?
The elbow joint capsule is lax in front and behind to permit a range of movements. It is also more extensive posteriorly to accomodate fat pads. It covers the bony articular surfaces and both coronoid and radial fossae on the humerus. But the medial and lateral epicondyles are both extra-articular an extra-capsular.
Where are the collateral ligaments of the elbow located?
There is a medial and a lateral collateral ligament on the elbow.
The medial collateral ligament is triangular and consists of anterior, posterior and middle bands. It extends from the medial epicondyle of the humerus and the olecranon to the coronoid process of the ulna. The ulnar nerve lies adjacent to the medial collateral ligament as it passes forwards below the medial epicondyle.
The lateral collateral ligament extends from the lateral epicondyle of the humerus to the annular ligament. The annular ligament is attached medially to the radial notch of the ulna and clasps, but does not attach to the radial head and neck. Because of this, the radial head is free to rotate within the ligament.
What are the movements of the elbow?
Flexion and extension occur mainly at the elbow joint.
Pronation and suppination occur at the superior radio-ulnar joint.
Flexion - is achieved by the anterior arm muscles, biceps, brachialis and brachioradialis.
Extension - triceps mainly, and anconeus
Pronation - pronator teres and pronator quadratus
Supination - biceps is the most powerful supinator. This is because of the insertion of the biceps tendon into the posterior aspect of the radial tuberosity. Supinator, extensor pollicis longus and brevis are weaker supinators.
What are the boundaries of the cubital fossa?
The fossa is defined by a horizontal line joining the two epicondyles, the medial border of brachioradialis and the lateral border of pronator teres.
The floor of the fossa is formed by brachialis muscle and the roof by superficial fascia. The median cubital vein runs in the roof of the fascia and drains into the basilic and cephalic veins.
What is the biceps tendon and important landmark for in the cubital fossa?
The biceps tendon can be easily palpated in the fossa. Medial to the biceps tendon is the brachial artery and the median nerve.
NB - the radial and ulnar nerves lie outside the fossa. The radial nerve passes anterior to the lateral epicondyle between brachialis and brachioradialis muscles. The ulnar nerve winds behind the medial epicondyle.
What are the common presenting complaints of elbow pathology?
Most patients will present with either:
- locking, caused by loose bodies
- pins and needles, hand weakness
What is tennis and golfer's elbow?
Tennis elbow is lateral epicondylitis, golfers elbow is medial epicondylitis.
Patients are often middle aged and may have a history of pain commencing after minor trauma. There may be a recent history of excessive activity involving the elbow (but this is rarely tennis!).
In tennis elbow the pain is located on the outer aspect of the elbow, whereas in golfers elbow the pain is located medially.
The exact cause of pain is unknown, but it is likely to be caused by vascular repair due to tendon microtrauma.
What is Mill's test?
This is pain felt over the lateral or medial elbow on resisted wrist extension or flexion respectively. It suggests tennis or golfers elbow.
NB - the reason the pain is felt either on extension or flexion is because the lateral or medial epicondyles are the origin of the long forearm extensors and flexors respectively.
What is the management of tennis or golfer's elbow?
1) conservative - NSAIDs, activity modification (avoid precipitating movements), physio, steroid + local anaesthetic injection
2) surgical - persistant pain which fails to respond to conservative measures. The collateral ligament on the side of pain is removed from the humeral epicondyle which decompresses the elbow
What is olecranon bursitis? What other differentials are there?
This is otherwise known as "student's elbow" and is a traumatic bursitis following pressure on the elbows - e.g. while reading a book.
Symptoms are pain and swelling behind the olecranon. Other differentials are septic arthritis (check for signs of sepsis) and gout bursitis (check for tophi).
The bursa should be aspirated and a sample sent for MC&S and crystals (gout crystals are negatively birefringent).
Treatment is usually with steroid injections directly into the joint with local anaesthetic. If the cause is infective then the joint needs surgical drainage to remove pus followed by IV antibiotics.
What is ulnar neuritis?
Ulnar neuritis is also called "cubital tunnel syndrome". It occurs due to impingement of the ulna nerve as it passes behind the median epicondyle.
- osteoarthritic and rheumatoid narrowing of the ulnar groove
- friction of the nerve due to cubitus valgus (congenital abnormality) and nerve fibrosis
- supracondylar fracture (most common fracture in children)
How does ulnar neuritis present?
Sensory symptoms usually occur first - e.g. decreased sensation in the ulna nerve distribution, ulnar 1.5 fingers . Patients may experience clumsiness of the hand and weakness of the small muscles supplied by the ulnar nerve (of the 20 bones in the hand the ulnar nerve supplies 15).
How is ulnar neuritis diagnosed?
Diagnosis is usually clinical, but nerve conduction studies can be performed to isolate the site of the lesion. Ulnar neuropathy can occur at multiple sites from the elbow downwards with the cubital tunnel and Guyon's canal be most common.
How is ulnar neuritis treated?
Management is conservative followed by surgery. Surgical intervention is usually offered if patients are not responding to conservative therapy, being kept awake by night time pain or decreased function. It involves decompression +/- transposition of the nerve to the front of the elbow (often only performed if the nerve subluxes over the medial epicondyle during decompression).
What is the ulnar paradox?
The ulnar nerve can be damaged at various points from the elbow downwards. When the ulnar nerve is damaged at the wrist in Guyon's canal the hand becomes clawed. The interossei and lumbricals usually produce flexion at the MCP joints and extension at the IP joints. When the function of the interossei and lumbricals is lost, the opposite happens and the MCP joints become extended and IP joints flexed. This is less noticeable in the index and middle fingers because they retain their lumbrical muscles which are supplied by the median nerve.
If the ulnar nerve is injured at the elbow or above, the ring and little fingers get straighter as the ulnar supply to flexor digitorum profundus gets lost which means they are held in a less flexed position. But, this results in greater functional disability. This is the paradox, we would expect the clawing to become worse the higher the injury but it appears to get better.
What are the features of osteoarthritis of the elbow joint?
OA of the elbow joint presents as pain and stiffness in all elbow movements, e.g. flexion, extension and forearm rotation. Loose bodies may cause further restriction of movement - e.g. loss of full extension.
Primary OA of the elbow is rare, and it normally occurs secondary to fractures or osteochondritis dissecans.
How is elbow OA treated?
Treatment is mostly conservative - activity modification, phsyiotherapy, NSAIDs, analgesics.
Surgery is rarely needed, but procedures include removal of loose bodies, debridement , joint replacement or radial head excision.
What is cubitus valgus?
There is a normal degree of valgus called the carrying angle of between 10-15 degrees. Fractures at the lower end of the humerus or interference of the epiphyseal growth plate (i.e. causing arrest) may cause this angle to be greater. As a result, patients are more prone to OA and ulnar neuritis.
What is cubitus valgus associated with?
What can cause cubitus varus?
This may occur after poorly reduced supracondylar fractures.
What is the most common fracture in children? What is the main complication?
Supracondylar fracture is the most common fracture of children with a peak incidence between the ages of 5-7.
Depending on their exact type they may compromise brachial artery, median (typically anterior interosseus branch), radial or ulnar nerve function so check neurovascular status. Keeping the elbow in extension after injury prevents exacerbating brachial artery damage from the time of injury.
How should supracondylar fractures be managed?
Avoid flexing the elbow to >90 degrees. The exact management depends on the type of fracture as outlined in the Gartland classification system:
Type I fractures = non displaced fractures and can be managed by a cast and sling
Type II fractures = may require reduction under GA
Type III fractures = require surgery
Management is also determined by whether there is condylar involvement. Fracture of the medial epicondyle may require surgery if there are bone fragments in the joint or ulnar nerve compression symtpoms. Lateral epicondylar fractures can lead to cubitus valgus and ulnar nerve palsy. T shaped intercondylar fractures are supracondylar fractures with a break between the condyles.
What are the radiological findings of elbow fracture?
The two most common findings seen on x-ray are the "anterior sail sign" or the "posterior fat pad sign".
The anterior fat pad sign can be seen on a lateral elbow x-ray as a radiolucent triangle in front of the distal humerus. It can be present in a normal elbow and is only abnormal if it is raised off the bone by an effusion.
A visible posterior fat pad is always abnormal. The abscence of either of these signs makes a fracture very unlikely.
Note that elbow fracture is not the same as supracondylar fracture which involves the distal humerus.
How should elbow fractures be managed?
If there is no obvious fracture on imaging (remember to get at least 2 views), but if an effusion is present treat initially with a broad arm sling. Re x-ray after 10 days (the fracture will be easier to see as the effusion subsides). If the x-ray is clear then start mobilisation. If it is fractured then internal fixation may be required.
Physio and mobilisation are important in preventing stiffness.
What causes fractures of the radial head?
Fractures to the radial head often occur following a fall onto an outstretched hand. The elbow is painful, swollen and tender over the radial head.
There may be normal flexion and extension, but supination and pronation may be painful.
How are radial head fractures classified?
1) Undisplaced fractures - these are difficult to see on plain film x ray so associated features are used to identify the fractures (e.g. posterior fat pad seen as an area of lucency at the posterior aspect of the distal humerus is abnormal and indicates a joint effusion). If no further fractures are seen and the clinical signs and symptoms are suggestive then an undisplaced radial head fracture can be diagnosed. These are usually managed with analgesia and a sling
2) Displaced fractures - the radial head should align with the capitulum of the humerus. If there is a fracture and displacement of the head this is called a displaced fracture. These fractures should be corrected with internal fixation to minimise the risk of painful pronation and supination
3) Comminuted fractures - this is where the radial head is fractured in 2 places. These are managed according to severity
How many radial head fractures are associated with the "terrible triad" and what is it?
3-14% are associated with (i) fracture, (ii) elbow dislocation, and (iii) coronoid process fracture.
This is important, because it can result in joint instability and post traumatic complications. Radial nerve injury may occur with severe anterior displacement but it is rare.
What is meant by the term "pulled elbow"? How can it be corrected?
This refers to a situation where the radial head slips out of the annular ligament. Typically a patient aged 1-4 is lifted by the arms forcefully during play. The patient holds the arm slightly flexed and twisted inwards.
Reduction is achieved by cradling the elbow with thumb and forefingers over the radial head and either hyperpronating or supinating and flexing the elbow.
Imaging is not needed, but it can recur in 25% of cases.
What causes an elbow dislocation?
This can be caused by a fall onto and as yet not fully outstretched hand, with the elbow flexed. The impact causes posterior ulnar displacement on the humerus and a swollen elbow fixed in flexion.
Damage to the brachial artery and median nerve are rare but check for neurovascular status.
What separates the forearm into distinct compartments?
2 structures separate the forearm into an anterior (flexor) and a posterior (extensor) compartment. This is the interosseous membrane and the deep fascia. This is continuous with the fascia of the arm and is firmly attached to the periosteum of the subcutaneous border of the ulna.
The idea of compartments is important, because each compartment receives its own blood and nerve supply. Generally, veins are located in the subcutaneous tissue above the arteries and deeper nerves.
How are the muscles of the anterior compartment separated?
All the muscles of the anterior compartment are forearm flexors. They are divided into superficial, intermediate and deep muscles.
All the superficial muscles and the ulnar head of flexor digitorum superficialis (an intermediate muscle) arise from the common flexor tendon which is located on the medial epicondyle of the humerus.
Superficial flexors are: pronator teres, flexor carpi radialis, palmaris longus and flexor carpi ulnaris. Brachioradialis is also a superficial muscle but originates on the lateral supracondylar ridge of the humerus and is actually an extensor!
Flexor digitorum superficialis is the only member of the intermediate group.
Deep flexors: flexor digitorum profundus, flexor policis longus and pronator quadratus.
Which 2 muscles in the anterior forearm have duel innervation?
Most of the muscles in the anterior forearm compartment are innervated by the median nerve with the exception of flexor carpi ulnaris and the ulnar half of flexor digitorum profundus which are innervated by the ulnar nerve.
Describe the course of the ulnar nerve in the forearm?
The ulnar nerve enters the forearm by passing behind the median epicondyle of the humerus and entering the cubital tunnel. When it emerges it passes between the 2 heads of flexor carpi ulnaris (which it supplies) and continues distally towards the wrist.
The ulnar nerve also supplies half of flexor digitorum profundus. In the lower forearm, the ulnar nerve lies medial to the ulnar artery and the tendon of flexor carpi ulnaris. Here it gives of a dorsal superficial branch to supply the backs of the medial 1.5 digits.
It enters the wrist superficial to the flexor retinaculum and divides into its terminal branches.
What re the terminal branches of the ulnar nerve?
These are superficial branch supplying the skin of the medial 1.5 digits and a deep branch supplying:
- hypothenar muscles (flexor digiti minimi, abductor digiti minimi, opponens digiti minimi)
- medial 2 lumbricals
- all the interossei
- adductor pollicis
What is the blood supply to the anterior forearm compartment?
Ulnar artery and its anterior interosseous branch; radial artery.
What is the arrangement of the forearm extensor muscles?
The extensor muscles are located in the posterior forearm compartment. Brachioradialis and extensor carpi radialis longus originate from the lateral supracondylar ridge of the humerus.
The other muscles considered in superficial and deep layers which are both innervated by the posterior interosseous branch of the radial nerve. The superficial muscles originate from the common extensor tendon located on the lateral epicondyle of the humerus. The muscles of the deep layer arise from the back of the radius, ulna and interosseous membranes.
What is the neurovascular supply to the posterior compartment of the forearm?
The posterior interosseous artery (branch of the common interosseous artery) and posterior interosseous nerve (branch of the radial nerve) supply the posterior compartment of the arm.
Describe the course of the radial nerve in the arm and forearm?
The radial nerve arises as a continuation of the posterior cord of the brachial plexus. In the arm it runs with profunda brachii artery between the long and medial heads of triceps into the posterior compartment and carries on down between the two heads. At the midpoint of the arm it enters the anterior compartment by piercing the lateral intermuscular septum. In the region of the lateral epicondyle the radial nerve lies under the cover of brachioradialis and divides into the superficial radial and posterior interosseous nerves.
The radial nerve innervates all of the arm extensors.
Describe the course of the median nerve in the upper limb?
The median nerve initially lies lateral to the brachial artery but crosses it medially in the mid arm. In the cubital fossa, the median nerve lies medial to the brachial artery which itself lies medial to the biceps tendon. The median nerve then passes deep to the bicipital aponeurosis before passing between the two heads of pronator teres. A short distance below this, the anterior interosseous branch is given off. This descends with the anterior interosseous artery to supply the deep flexor muscles of the forearm with the exception of the ulnar half of flexor digitorum superficialis.
In the forearm, the median nerve lies between flexor digitorum superficialis and flexor digitorum profundus. A short distance above the wrist it emerges from the lateral side of flexor digitorum superficialis and gives off the palmar cutaneous branch. In then enters the hand through the carpal tunnel together with 9 tendons (4 from flexor digitorum superficialis, 4 from flexor digitorum profundus and 1 from flexor pollicis longus).
What is the carpal tunnel? What forms it?
The carpal tunnel is formed by the carpal bones and the overlying flexor retinaculum. It is through this tunnel that most, but not all, of the long flexor tendons originating in the forearm enter the hand. The flexor retinaculum is attached to four bony points - the pisiform, the hook of hamate, the scaphoid and the trapezium.
The carpal tunnel is narrow and no arteries or veins are transmitted through it because of the risk of compression. The median nerve does pass through however, and is at risk of compression.
What are the contents of the carpal tunnel?
9 tendons and 1 nerve:
- 4 tendons of flexor digitorum superficialis
- 4 tendons of flexor digitorum profundus
- 1 tendon of flexor pollicis longus
- median nerve
Why is the arrangement of the synovial sheaths of the flexor tendons important?
The synovial sheaths surround the flexor tendons and reduce friction between the tendons and the fibrous flexor sheaths of the digits. The tendon of flexor pollicis longus has its own synovial sheath which forms the radial bursa. Whilst flexor digitorum profundus and superficialis share one called the ulnar bursa that ends in the palm except for the little finger.
This arrangement is important in tendon sheath infections. Infection of the little finger sheath can spread to the whole of the ulnar bursa and even to the radial bursa through a communication that sometimes exists between them. Infections of other fingers however, are restricted to that finger.
What type of joint is the wrist?
The wrist is a condyloid synovial joint. The distal radius and a triangular disc of fibrocartilage covering the distal ulna form the proximal articulating surface. This disc is attached to the ulnar notch of the radius and to the base of the styloid process of the ulna. It separates the wrist joint from the inferior radio-ulnar joint. The distal articulating surface is formed by the scaphoid and lunate bones.
What is the nerve supply to the wrist joint?
Nerve supply comes from the anterior interosseous (median) and posterior interosseous (radial) nerves.
What is Dupuytren's contracture?
This is painless fibrotic thickening of the palmar fascia with skin puckering and tethering. Ring and little fingers are affected the most.
It is often bilateral and symmetrical. As thickening occurs there may be MCP joint flexion. If interphalangeal joints are affected then the deformity can be very disabling.
What conditions are associated with Dupuytren's?
The cause of Dupuytren's is multifactorial. Possible causes include:
- Genetics (AD)
- Peyronie's disease
How is Dupuytren's treated?
Surgery (e.g. fasciectomy) aims to remove affected palmar fascia and release the contracture. As a general guide, if the patient cannot rest their palm flat on a flat surface (Hueston's table top test) then refer for surgery.
Recurrence is common.
What is a ganglia?
Ganglia are cysts and appear as smooth multilocular swellings containing jelly like fluid in communication with joint capsules or tendon sheaths. They may disappear spontaneously and local pressure may disperse them.
When does a ganglia require treatment?
A ganglia should only be treated if it causes the patient pain or pressure (e.g. compression of the median or ulnar nerve at the wrist). Aspiration via a wide bore needle may work or they may be surgically disected out. This gives rise to less recurrence but problems include painful scars, neurovascular damage and recurrence.
What is De Quervain's disease?
This refers to stenosing tenosynovitis (thickening and tightening) of the abductor pollicis longus and extensor pollicis brevis tendons (at the anterior border of the anatomical snuffbox) as they cross the distal radial styloid.
Pain is worse when these tendons are stretched and proximal than that from osteoarthritis of the 1st carpometacarpal joint. Finkelstein's sign is pain elicited by sharply pulling on the relaxed thumb to causeulnar deviation.
What causes De Quervain's disease?
The cause is unknown, but symptoms can be exacerbated by overuse of the tendons.
How is De Quervain's disease treated?
First try rest (thumb spica splint), ice and NSAIDs. Hydrocortisone injection at tend side during the 1st 6 months of symptoms is effective in 90% of patients. If injection and rest fail to relieve, decompression of the tendons is provided by splitting the tendon sheaths, >80% do well post op.
What is trigger finger? Which fingers are most
Trigger finger (or tendon nodules) is probably caused by a swelling of the flexor tendon, or tightening of the flexor tendon sheath. Ring and middle fingers are most commonly affected, and the thumb especially in babies and children. Swelling of the tendon sheath along with nodule formation on the tendon, proximal to the A1 pulley prevents smooth gliding of the tendon. As a result, the tendon "catches" causing the finger to lock in flexion. As extension occurs the nodule moves with the flexor tendon, but then becomes jammed on the proximal side of the pulley, and has to be flicked straight so producing triggering.
How is trigger finger treated?
Simple immobilisation is the initial treatment of choice. If severe, steroid injection into the region of the nodule may be tried (not if the patient is a child, has renal failure or diabetes). Risk of recurrence is high, so surgery may be needed.
What is Volkmann's ischaemic contracture?
This follows compartment syndrome or interruption of the brachial artery near the elbow (e.g. after supracondylar fracture of the humerus). Muscle necrosis (especially flexor pollicis longus and flexor digitorum profundus) result in contraction and fibrosis causing a flexion deformity at wrist and elbow with forearm pronation, wrist flexion, thumb flexion and adduction, digital MCP joint extension and interphalangeal joint flexion.
Suspect compartment syndrome if a damaged arm has no radial pulse, and passive finger extension is painful (a crucial sign).
How is Volkmann's contracture treated?
Firstly, remove any constricting splints, and warm other limbs (promotes vasodilation). If pulse doesn't return within 30 mins, exploration of the artery is needed.
To treat the contracture, release of any compressed nerves and tendon lengthening usually restores lost function.
What is the function of the flexor tendon pulley mechanism?
In order to stop the long flexor tendons of the hand bowing when the fingers are flexed, the fingers have a number of pulleys attached to the bones and volar plates beneath. Named as either A for annular or C for cruciate, there are 5 A pulleys and 3 C pulleys. The most important are A2 (which is at the proximal end of the proximal phalanx) and A4 (at the middle of the middle phalanx) both of which NEED to be preserved during any surgery to prevent bowing of the flexor tendons.
What is a Colles fracture?
This is a distal radius fracture.
It occurs following a fall onto an outstretched hand.
Most common in elderly females with OA.
Physical signs include the dinner fork deformity.
How should a Colles' fracture be managed?
Examine for neurovascular injury as the median and radial nerves are close.
If there is considerable displacement then reduce the fracture:
- under haematoma block, IV regional anaesthesia (Bier's) or GA
- Disimpact and correct angulation
- Position: ulnar deviation + some wrist flexion
- Apply dorsal backslab: provide 3 point pressure
Re-X ray, satisfactory position?
- No: ortho review and consider MUA +/- K wires
- Yes: home with fracture clinic review, and follow up fowithin 48 hours