Orthopedic Pitfalls: Approach to Upper Limb X-rays

1. Orthopedic Pitfalls:Approach to Upper Limb X-rays Yael Moussadji, PGY 3 Dr. Phil Ukrainetz Nov 2, 2006

2. Objectives • To review diagnosis and management of upper extremity orthopedic injuries • To highlight injuries that are frequently missed or mismanaged • To review, in detail, orthopedic “pitfalls” including • Posterior shoulder dislocations • Elbow fractures • Forearm fractures • Wrist injuries

4. Classified according to the final position of the humeral head Subcoracoid dislocations are most common (70%), followed by subglenoid (30%) Subclavicular and intrathoracic are associated with violent forces, fractures, and are extremely rare Anterior Shoulder Dislocations

5. Clinical Features • Arm held in slight abduction and external rotation by other extremity • Shoulder may have a squared off appearance, with fullness of anterior shoulder • Patient cannot adduct of internally rotate without severe pain • 5-54% may have axillary nerve injury, assessed by testing for sensation over lateral shoulder and motor function of deltoid (more accurate)

6. Associated fractures in 50% Most common is the Hill Sachs deformity, compression fracture of the posterolateral humeral head Bankart’s lesions may be present in up to 5% Avulsion fractures of the greater tuberosity account for 10-15% Associated Fractures

7. Selective radiology in 100 patients with suspected shoulder dislocation. The Journal of Emergency Medicine. Hendey et al, 2006. • Prospective validation of a previously derived clinical decision rule for selective radiography of patients with suspected shoulder dislocation in the ED • Pre and post reduction radiographs were ordered based on the algorithm incorporating mechanism of injury, previous dislocations, and physicians clinical certainty of joint position • 94 of 100 patients had shoulder dislocations, of which 59% were recurrent • 30% had both pre and post films, 45% had either pre or post, and 25% had none • There was a 46% reduction in x-ray utilization, with no missed fractures or dislocations, with the greatest potential for saving noted in the subset of patients with recurrent atraumatic dislocations • Previous studies have indicated that fracture dislocations can be predicted by 3 variables: first time dislocations, blunt traumatic mechanism (fall > 1 flight stairs, assult, MVC), age >40

8. Algorithm for Shoulder Radiography in the ED

9. Shoulder Reduction • Traction-counter traction • Stimson technique • Patient is placed prone with the affected limb hanging downwards in forward flexion at the shoulder; patient remains in that position with 5-10 pound weights suspended from the wrist; can take 15-20 min • External rotation • Slow gentle external rotation of the adducted arm; reduction occurs between 70 and 110 degrees • Can be done supine or sitting (80% successful) over 5-10 min • Scapular manipulation • Focus is on repositioning the glenoid fossa (85% successful) • Arm held at forward flexion with slight traction • Superior aspect of scapula is stabilized, while the inferior tip is adducted with the thumb

10. Others (Milch, Spaso etc) all employ some degree of traction and external rotation to simulate the mechanism in which dislocation occurred

11. Posterior Shoulder Dislocation • The most commonly missed joint dislocation in the body • Incidence of 1-4% of all shoulder dislocations • 79% are incorrectly diagnosed • Must have a high index of suspicion in order to seek out the classic physical findings

12. History • Occurs when the arm is forward flexed and slightly internally rotated with axial load applied, eg hitting a heavy punching bag or striking the dash with arm extended to the front • Classic history is a significant blow to the front of the shoulder, or a FOOSH with the elbow extended and humerus internally rotated • Posterior dislocations are the result of indirect forces producing a combination of internal rotation, adduction, and flexion • Can also be encountered in patients with seizures, alcohol withdrawal, or electrocution

13. Physical Exam • Generally, patients complain of severe pain (more painful than anterior dislocations) • Patient will usually be sitting with arm held tightly across front of trunk, fixed in a position of adduction and internal rotation • External rotation is blocked and abduction is severely limited • The posterior aspect of the shoulder is rounded and more pronounced, and the anterior portion will be flattened with a prominent coracoid process • Clinical pearl: Patients will be unable to supinate the palm (always present)

14. Radiographs: AP view

15. AP view • Absence of the normal elliptical shadow • On a routine AP view there is usually an overlap shadow created by the head of the humerus imposed on the glenoid fossa; in a posterior dislocation, the articular surface of the humeral head is posterior to the glenoid, distorting the elliptical overlap shadow; the inferior third of the glenoid fossa usually has no contact with the humeral head • Vacant glenoid sign • The humeral head normally occupies the majority of the glenoid cavity; in posterior dislocations the head rests behind the glenoid, producing a positive rim sign; if the space between the anterior rim and the humeral head >6mm, posterior dislocation is likely • The “trough line” • An impaction fracture of the humeral head caused by posterior rim of glenoid resulting in two parallel lines of cortical bone on the medial cotext of the humeral head • “Hollowed out” or “cystic” humeral head • Arm locked in internal rotation, aligning the greater and lesser tuberosities

16. Shoulder radiographs • Caution: the AP view does not represent a true AP of the glenohumeral joint (scapula lies at 45 degrees, angulating the glenohumeral joint space anteriorly at 45 degrees) • Therefore loss of the joint space in a posterior dislocation may not be visualized on a normal AP of the shoulder • An axillary or scapular view is required

17. Most clinically useful AND patient friendly Virtually diagnostic of posterior shoulder dislocation Taken sitting or standing or supine with arm left undisturbed Anterolateral portion of shoulder placed against the cassette X-ray beam passes tangentially across posterolateral chest parallel to and down from spine of scapula onto cassette This represents a true lateral of the scapula, and therefore the glenohumeral joint Scapular lateral

18. In the lateral view, the scapula projects as the letter Y The vertical stem of the Y is the body of the scapula; the upper fork is formed by the juncture of the coracoid and the acromion process The glenoid is located at that junction In a posterior dislocation, the humeral head will be posterior to the glenoid Scapular lateral

19. Requires the patient to lie supine and abduct the arm 70-90 degrees with cassette above shoulder and tube near hip 2 modified axillary views available in patients who are in too much pain to tolerate Axillary lateral

20. Humeral head posterior to glenoid fossa Dots and arrows indicate trough lines (reverse Hill Sack’s lesions) B = Bankhart fracture fragment Axillary lateral

21. Management • Management depends on the presence of and size of the anterior impression fracture; incidence of co-existent fractures is 50% • When humeral head lesion <20% of articular surface, closed reduction may be attempted • Many may go on to need general anesthetic • Place patient supine and apply traction to the adducted arm in the line of deformity • While applying traction, gently lift the humeral head back into the glenoid fossa • If the head remains locked on the glenoid rim, apply lateral traction on the upper arm using a folded towel • Traction is maintained while the arm is then slowly externally rotated • Do not force the arm into external rotation; this may fracture the humerus • The arm is then immobilized in external rotation and slight abduction

23. Luxatio Erecta(a.k.a. inferior shoulder dislocation) • Comprises 0.5% of all shoulder dislocations, and can be misdiagnosed as an anterior dislocation • Mechanism is injury involves hyperabduction of arm at shoulder with extension at elbow while forearm pronated • Direct violent force applied to superior shoulder, causing inferior movement of humeral head relative to glenoid fossa disrupting the inferior glenohumeral capsule

24. Patients usually present with arm hyperabducted at shoulder and flexed at elbow with forearm resting behind the head Glenoid fossa is empty and humeral head is palpated in axilla AP view demonstrates inferior displacement of humeral head Axillary view Clinical presentation

25. Management • Closed reduction with muscle relaxation and anesthesia • In-line traction to the fully abducted arm with firm cephalad pressure on humeral head • Counter-traction using rolled bed sheet placed superior to shoulder • Once humeral head reduced, arm adducted towards body and forearm supinate • Outpatient orthopedic referral • Associated injuries include rotator cuff injuries, fractures of the clavicle, coracoid, acromion, inferior glenoid, greater tuberosity of humerus (80% of cases) • 60% suffer axillary nerve injury

27. Supracondylar fractures • Bony injury of distal humerus proximal to the epicondyles • Mean age of 7 years, rare beyond 15 • Similar injury mechanisms in adults produce posterior elbow dislocations • Classified as flexion type or extension type (95%) • Extension type supracondylar fractures result from FOOSH with elbow fully extended; force of impact directed forward fracturing the anterior aspect of the distal humerus; contraction of the triceps pulls the distal fragment posteriorly and proximally

28. Radiography • Type I • Minimal to no displacement • Type II • Incomplete injury, minimal to moderate displacement and/or intact posterior cortex • Type III • Complete displacement of fragment with posterior cortical disruption

29. Anterior humeral line should bisect the middle of the capitellum; in a supracondylar fracture, the line will strike the anterior third or miss it entirely Fat pad sign results from swelling adjacent to the distal humerus; the posterior fat pad is never seen in an uninjured patient and is associated with fracture in 90% Occult fracture

30. Management • Type I • Mechanically stable; splint for pain control and comfort • Type II • Reduction, preferably by ortho (yeah right) • Cast at 120 degrees of flexion • Type III • ED reduction • Associated with loss of arm length, deformity, neurovascular compromise • Apply traction at wrist in line with upper extremity with thumb in up position while correcting any medial or lateral deformity • When arm length restored, slowly and gently flex elbow to 100 degrees • Immobilize medially displaced fractures with forearm pronated and laterally displaced fractures with forearm supinate

32. Usually results from FOOSH in adults Impact transmitted axially, forcing radial head against capitellum X-ray may detect fracture or only pathological fat pads suggestive of occult fracture Any irregularity in radial head, especially in association with fat pads is a radial head fracture until proven otherwise Radial HeadFractures

33. Type I undisplaced Type II Minimally displaced Type III comminuted Type IV Fracture-dislocation Radial Head #Mason Classification

34. Management • Type I • Treat symptomatically with sling and early ROM • Type II • Treat as Type I; patients may require radial head excision if fails ROM maneuvering • Type III • Early ortho follow-up for excision of radial head • Type IV • Reduction and early surgical excision • Outcomes excellent

36. Galeazzi and Monteggia fracture dislocations • Dislocation at the elbow or wrist may accompany any forearm fracture • Monteggia pattern of injury consists of a fracture of proximal third of ulna with dislocation of radial head • Galeazzi pattern of injury consists of radius fracture, most often at junction of middle and distal third, with dislocation at DRUJ

37. Proximal dorsally angulated ulna fracture Radiocapetellar line misses the capitellum indicating a proximal radial head dislocation Monteggia

38. Comminuted distal radius fracture Subtle disruption of DRUJ evident by shortened radius and loss of overlap between radius and ulna Galeazzi

39. Mechanism • Can be caused by low energy (FOOSH) while hyperpronated or high energy (MVC) • Galeazzi is three times more common; miss rate of up to 50% in diagnosis quoted in some studies • Monteggia fractures result in an ulnar shaft fracture with an anterior radial head dislocation in 60% • Galeazzi fractures usually occur distal to biceps tuberosity and proximal to 4cm from distal radius; with displaced radial shaft fracture, DRUJ disruption is common but frequently subtle • May be purely ligamentous, or may involve fracture of ulnar styloid

40. Presentation • Monteggia • Extremely limited ROM of elbow, especially flexion and supination • Dislocated radial head may be palpable • Deep branch of radial nerve may be affected resulting in weakness of extension of fingers/thumb • Galeazzi • Resist any attempts at pronation and supination • Ulnar styloid process may be prominent • However, in nondisplaced fractures the patient may not complain of any wrist pain

41. Ulna fracture usually clearly evident ALWAYS measure the radiocapitellar line to avoid missing a radial head dislocation If the ulnar fracture is angulated, the apex of angulation points in the same direction as the dislocation Radiography: Monteggia

42. Radius fractured and shortened Increased space between distal radius and ulna on PA (should not be wider than 1-2mm) On lateral, fractured radius angulated dorsally and ulna appears dorsally displaced (normally overlies the radius) Inability of the tech to get a true lateral should raise suspicion of injury Radiography: Galeazzi

43. Management • Monteggia fractures can be successfully treated in children with closed reduction and supinated long arm splinting • More severe injury in adults, required ORIF • Galeazzi in particular is prone to poor outcome if missed (>90%) • Treated with ORIF of fracture and pin or open fixation of DRUJ

44. Wrist Sprain?

45. Wrist Injuries • The most common but inaccurate diagnosis made in wrist injuries is wrist sprain • This should be a diagnosis of exclusion • Commonly missed injuries include scaphoid fractures, scapholunate dissociations, lunate and perilunate injuries, DRUJ dislocations, hamate hook fractures, and triquetral avulsion fractures

46. Clinical Approach • Demonstration of specific point tenderness is the most important diagnostic test, so know your anatomy • Anatomic snuffbox sits between the extensor pollicus longus and extensor pollicus brevis when the thumb is radially abducted; body of scaphoid is palpated here • Scaphoid tuberosity palpable at the base of the thenar muscles on palmar aspect of wrist • Pisiform palpable at the junction of the flexor carpi ulnaris and volar wrist crease; just distal to this lies the hook of the hamate • On dorsal wrist palpate Lister’s tubercle; the scapholunate ligament is just distal to this • Just distal to ulnar head and radial to its styloid lies the lunotriquetral junction

47. Scaphoid fractures • Accounts for 60-70% of all wrist fractures, and is the most commonly missed injury • Scaphoid links the proximal and distal carpal rows and is the principle bony block to wrist extension • Classic history is a FOOSH with hyperextension at the wrist in 97% of cases • Immediate pain, minimal swelling, and patient is able to continue on with daily activities • Palpation in the anatomic snuffbox is the most reliable diagnostic maneuver

48. Scaphoid fractures • Fracture of the middle third is most common (80%), followed by proximal third (15%), distal third (4%) and distal tubercle (1%) • Propensity for nonunion and AVN caused by blood supply which arises distally • Proximal bone is completely dependent on this blood supply and most at risk • Common associated injuries include fractures of distal radius, lunate, or radial head; median nerve injury has also been described • 10-20% of fractures are not visible on initial x-rays

49. Scaphoid view positions wrist in ulnar deviation, placing scaphoid in extended position, allowing you to view the entire length of the scaphoid Also accentuates any scapholunate dissociation X-rays

50. Management • Treat all suspected fractures as though one exists, with thumb spica splint and f/u in 7-10 days for reassessment and repeat X-rays • 15% are ultimately shown to have a fracture • For confirmed fractures, treat with long arm thumb spica splint with hand clinic follow-up in 7 days • Consult a hand surgeon on presentation if any significant angulation, displacement, or comminution