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Jonny Kent and Faizan Jabbar
The median nerve runs between the two
heads of pronator teres making it a possible site
of entrapment.
The ligament of Struthers is a connective
tissue band on the medial aspect of the distal
humerus. Struthers originally estimated that it
was present in 1% of humans. It is a potential
site of compression to the ulnar nerve.
The arcade of Struthers is a musculoaponeurotic canal that is formed by the attachments
of the internal brachial ligament (a fascial extension of the coracobrachialis tendon), the fascia
and superficial muscular fibres of the medial
head of the triceps, and the medial intermuscular
septum. It may cause entrapment or compression of the ulnar nerve.
The flexor digitorum superficialis (FDS) arch
is a potential site of median nerve compression
Supracondyloid
1
process
Brachial artery
Median nerve
Ligament of Struthers
2
Pronator teres
4
retracted
in the forearm. It is not an FDP arch. It can cause
pronator syndrome (PS).
PS presents as paraesthesia in the median
nerve distribution and aching pain in the proximal forearm with minimal weakness. It can be
confused with the more commonly diagnose d
carpal tunnel syndrome, as the clinical picture
can be very similar.
There are four additional sites of potential
compression besides the two heads of the pronator teres muscle. Other areas of potential compression include the lacertus fibrosis (bicipital
aponeurosis), the ligament of Struthers
(extending from a supracondylar process to the
medial epicondyle), by anomalous muscles such
as an accessory head of the flexor pollicis longus
(Gantzer’s muscle) and the flexor digitorum
superficialis (FDS) arch.
19. Answer B. Normal pronation strength with the
elbows fully flexed
The anterior interosseous nerve (AIN) innervates
2.5 muscles that are deep muscles of the forearm.
Flexor pollicis longus
Pronator quadratus
The radial (lateral) half of FDP (index and
main fingers)
Arch of the exor
5
digitorum supercialis m.
Figure 14.5 Sites of compression of the median nerve. (1)
Supracondylar process. (2) Ligament of Struthers. (3) Bicipital
aponeurosis. (4) Pronator teres. (5) Fibrous arch FDS
304
Bicipital
3
aponeurosis
The AIN supplies PQ. PQ is tested with the
elbow fully flexed to defunction the PT.
The AIN has no sensory innervation.
Flexion of the IPJ of the thumb is controlled
by the flexor pollicis longus (FPL) supplied by
the AIN.
Flexion of the DIPJ of the middle finger is
controlled by flexor digitorum profundus (FDP)
supplied by the AIN.
Flexion of the DIPJ of the index finger is
controlled by flexor digitorum profundus (FDP)
supplied by the AIN.
20. Answer B. Reassurance
Most cases (90%) of AIN palsy are due to neuritis
that can take up to 18 months to recover.
The scenario is of an AIN palsy. The patient
is unable to perform an ‘OK’ sign.
The patient would make a triangle sign
instead. This ‘pinch-test’ exposes the weakness of
the FPL muscle and the FDP leading to weakness
of the flexion of the DIPJ thumb and index finger.
Figure 14.6 Median nerve. Course, supplied branches
and anatomy
Shoulder/Elbow II Structured SBA
The long thoracic nerve arises from the upper
portion of the superior trunk of the brachial
plexus C5 C6 C7. The long thoracic nerve forms
as an upper portion originating from the C5 and
C6 nerve roots and a lower portion coming from
the C7 nerve root. The fusion of these two portions occurs in the axilla. Within the supraclavicular region, the upper division of the long
thoracic nerve travels parallel to the brachial
plexus near the suprascapular nerve. Due to its
long, relatively superficial course, the long thoracic nerve is susceptible to damage during certain
surgical procedures or through direct trauma or
stretch.
Ptosis is part of Horner syndrome character-
ised by a drooping eyelid (ptosis), decreased
pupil size (miosis) and dryness of the eye (anhidrosis). The syndrome results from damage to
the sympathetic nerve supply to the eye. This is
in the nearby vicinity of the BP and is usually
taken as an absolute indicator of avulsions of the
C8 and T1 ventral roots in the adult brachial
plexus.
Decreases in upper limb function following
BPI negatively affect postural control and balance, as observed by increases in body sway or
reduced performance in dynamic balance tests.
A raised hemidiaphragm suggests a C4 nerve
root injury. This can occur at the same time
as C5.
This results in impairment of the pincer movement and the patient will have difficulty picking
up a small item, such as a coin, from a flat surface.
The AIN innervates three muscles in the forearm: flexor pollicis longus (FPL), pronator quadratus (PQ) and the radial half of flexor digitorum
profundus (FDP). In the hand, the median nerve
innervates five muscles: The two lateral lumbricals, opponens pollicis, abductor pollic is brevis
and flexor pollicis brevis.
21. Answer A. Jobe test positive
The Jobe test or empty can test involves testing
the supraspinatus supplied by the suprascapular
nerve. All the other features listed are preganglionic signs of BP injury.
Medial winging of the scapula is caused by
weakness of the serratus anterior supplied by the
long thoracic nerve.
22. Answer C. Parsonage–Turner syndrome
Clinical symptoms of Parsonage–Turner syndrome include abrupt and acute onset of significant pain within the shoulder girdle and upper
arm followed by numbness and weakness within
the upper arm. Symptoms are usually unilateral,
and patients report a distinct sharp and radiating
pain circulating within the arm-pit region. Onset
of sharp and excruciating pain denotes the beginning of symptoms which then later transitions to
weakness and numbness over the course of a few
hours to days. The severe initial pain usually
subsides after weakness or paralysis develops.
This incidence and observation of pain translating to weakness is crucial to the accurate diagnosis of acute brachial plexus neuritis. Brachial
neuritis is more prevalent in men between the
ages of 30–70, is commonly diagnosed on the
right side and following surgery.
305
Jonny Kent and Faizan Jabbar
Peripheral nervous system infections
(Options A and B) are in the small print differe ntial diagnosis.
Lyme disease (borreliosis) is an infection
caused by Borrelia burgdorferi which is tr ansmitted by the tick Ixodes. The primary stage of the
disease is characterised by erythem a migrans
which begins 3–30 days after the tick bite. After
1 week to 3 months, a secondary stage which
affects the neurological system can occur and
can persist for several weeks or months. The
tertiary stage with neurological symptoms (‘late’
neuroborreliosis) can start 6 months after the
tick bite and can last for several years.
No mention of a tick bite or a preceding rash.
Again, no reason to suspect HIV infection
and nothing in the history to point you towards
this as the cause.
Distinction between post-operative PTS (brachial neuritis) and post-operative C5 palsy is very
difficult. C5 palsy shortly after recent cervical
decompression, due to migration of a graft or
intraoperative root injury is well recognised.
These would present earlier on post-operatively.
The history of intolerable pain, followed by
weakness and improvement of pain highly suggestive of PTS. Another important discriminator
is the fact that in case of PTS the weakness,
sensory deficit and pain usually do not correspond to the same nerve root or peripheral nerve
distribution. This is in sharp contrast with C5
palsy, where C5 motor symptoms predominate.
Thoracic outlet syndrome is in the DD, but
nothing is given in the history to point you in
this direction.
Comment: This SBA is too long to use in a
real FRCS (Tr&Orth) exam. It would need to be
cut down to about one-third in length. It is more
in keeping with USA type SBA where there is a lot
of clinical information contained within the stem.
Verhasselt S, Schelfaut S, Bataillie F, Moke
L. Postsurgical Parsonage–Turner syndrome: a
challenging diagnosis. Acta Orthop Belg.
2013;79:20–24.
23. Answer D. Opposition of the thumb
The lesion described is of a median nerve palsy.
This must be worked out from the SBA.
The last muscles to the innervated from the
median nerve are the first and second lumbricals.
However, to make the question more difficult,
the third and fourth lumbricals are included.
Adductor pollicis and the first dorsal
interossei.
To make the SBA easier, we could have substituted pronator teres as one of the options. This
is the first muscle to be innervated by the median
nerve. Including the first and second lumbrical as
an option might have made the question guessable to a streetwise candidate.
FCR – flexio n and abduction of the wrist.
FDS – flexion at the PIP joint main finger.
Abductor pollicis brevis – palmar abduction.
Opposition of the thumb – opponens pollicis.
Ring and little finger MCP joint flexion and
IP joint extension – third and fourth
lumbricals – ulnar nerve.
24. Answer B. Weakness of index finger extension
at the MCPJ and IPJs
The extensor indicis proprius is the last muscle
innervated by the PIN. Its action is to extend the
index finger at the MCPJ and IPJ. It would be
difficult to differentiate between abductor pollicis longus and extensor pollicis brevis.
EPL – extension of the IPJ thumb – PIN.
Extensor pollicis brevis – extension and
abduction of the thumb at the MCPJ and CMCJ.
Abductor pollicis longus – abduction thumb
at the CMC joint
Supinator muscle-forearm supination –
weakness unscrewing a jar – PIN.
25. Answer D. Ulnar collateral ligament (UCL) tear
The ulnar collateral ligament (UCL) is the primary structure responsible for stability of the
elbow joint against the valgus forces associated
with the throwing mechanism. The ligament
complex is composed of three bundles: the anterior, posterior and transverse bundles, with the
anterior bundle being the strongest component.
The anterior bundle originates on the medial
epicondyle of the humerus and inserts on the
tubercle of the ulna. This bundle is crucial in
the maintenance of joint stability during the late
cocking and early acceleration phases of overhead throwing. The anterior bundle of the UCL
is placed under the greatest amount of valgus
stress during the throwing motion, between 20°
– PIN.
306
Shoulder/Elbow II Structured SBA
abduction and externally rotated (palm up). A
constant moderate valgus torque is applied to the
fully flexed elbow and then the elbow is quickly
extended. The test is posit ive if the medial elbow
pain is reproduced at the medial collateral ligament and is at maximum between 120° and 70°.
26. Answer D. Medial head of triceps
With answer C, weakness of pinch is compensated for by a positive Froment’s sign, which
indicates proximal nerve compression rather
than within Guyon’s canal.
All other choices of sites of ulnar nerve com-
pression are possible, but the clue is bodybuilding. With bodybuilders there is hypertrophy of
the medial head of the triceps. This is an uncommon site of compression in the general
population.
There are several sites of ulnar nerve com-
pression around the elbow:
Arcade of Struthers.
Medial intermuscular septum.
Medial head of triceps.
Medial epicondyle.
Arcuate ligament.
Osbourne fascia.
Epicondylar groove.
Anconeus epitrochlearis.
Deep flexor pronator aponeurosis.
Figure 14.7 Ulnar nerve. Branches and anatomy
and 30° of elbow flexion as a result of the olecranon process unlocking from the olecranon fossa.
The valgus stress test for medial elbow joint
instability can be used to detect joint space gapping. In addition, the milking manoe uvre technique can be performed. This involves the
forearm being supinated fully and the elbow
flexed beyond 90°. The thumb is then pulled
laterally by the athlete’s contralateral extremity,
creating a valgus force on the elbow. Pain,
instability or apprehension is indicative of injury
to the UCL.
The most sensitive test is the moving valgus
stress test. The patient’s shoulder is placed in 90°
27. Answer B. Cut-off size for tears to be symptom-
atic is 2.5cm
The presence of rot ator cuff tears does not necessarily lead to clinical symptoms. A large number
of rotator cuff tendon tears are asymptomatic,
detected as incidental findings on radiological
imaging.
Failure of a rotator cuff tear repair is
common, seen in up to 30% of cases. However,
some patien ts who have a failed repair may be
pain free with good outcom es.
Physiotherapy along with activity modifications, anti-inflammatory and analgesic medications form the pillars of non-operative treatment.
Only around one-third of rotator cuff tears
cause pain.
Curry et al. (2015) have shown that pain and
functional status were not associated with tear
size or thickness, fatty infiltration and muscle
307
Jonny Kent and Faizan Jabbar
atrophy. Instead, poor mental health, female sex
and increased number of comorbidities were
associated with greater disability scores. As such,
pain and functional disability may have multiple
causes and should not be purely related to the
characteristics of the tear.
It is estimated 1 in 15 patients with a rotator
cuff tear has surgery for symptoms only.
Hinsley et al. (2014) used ultrasound to evaluate cuff tendinopathy in a general population
cohort. They reported 110 normal tendons, 217
abnormal tendons, 77 partial tears and 124 fullthickness tears. They reported that symptomatic
shoulders had a larger median tear size than
asymptomatic shoulders. When they looked at tear
size as a predictor of the presence of pain (trying to
decide the point at which full-thickness tears
become increasingly likely to be symptomatic),
they found the cut-off size to be 2.5cm; this would
be consistent with the difference between single
and multi-tendon tears and may signify the point
at which altered shoulder biomechanics occur.
Charalambous CP. The Shoulder Made Easy.
New York, N Y: Springer; 2019.
Curry EJ et al. Structural characteristics are
not associated with pain and function in rotator
cuff tears: the row cohort study. Orthop J Sports
Med. 2015;3(5).
Hinsley H et al. Classification of rotator cuff
tendinopathy using high definition ultrasound.
Muscles Ligaments Tendons J. 2014;4:391–397.
28. Answer A. A fall onto the outstretched hand
The majority of periprosthetic humeral fractures
are caused by low-energy mechanisms such as a
fall from standing or onto an outstretched hand.
It is important to determine whether or not pain
was present prior to the fracture, as that could be
a sign of implant loosening or low virulence
infection such as Propionibacterium acnes.
The treatment of post-operative fractures is
based on fracture location, prosthesis type and
stability, rotator cuff status and available bone
stock.
The main risk factor is humeral osteopenia.
Most patients are elderly females with a high
incidence of rheumatoid disease.
Fram B, Elder A, Namdari S. Periprosthetic
humeral fractures in shoulder arthroplasty. JBJS
Rev. 2019;7:e6.
29. Answer A. Injection of local anaesthetic into
the subacromial space
The history and clinical signs are of a classic
rotator cuff tear of the shoulder. There is pain
from subacromial impingement, muscle weakness and limited range of movement. After an
injection of local anaesthetic into the subacromial space, the shoulder could be moved through
a full range of movement, but actively there was
still limitation of abduction and forward flexion
to 50°. External rotation was still weak. This is
highly suggestive of a rotator cuff tear.
No single test alone is sufficient to diagnose
rotator cuff disease. Outpatient ultrasound scanning of the shoulder is simple, quick and affordable, and provides an immediate imaging
method as an adjunct to clinical evaluation and
a high rate of detection of full-thickness rotator
cuff tears.
One difficulty is that it is highly operator
dependent, and its accuracy in detecting rotator
cuff tears may vary, depending on the level of
expertise of the musculoskeletal radiologist and/
or shoulder surgeon.
MRI provides an anatomical picture, demonstrates the quality of rotator cuff muscles and the
degree of tendon retraction and shows other
eventual intra-a rticular and extra-articular pathologies. However, MRI examinations are expensive to perform, have longer waiting periods and
can be extremely problematic in claustrophobic
patients.
Walton and Murrell (2012) reviewed 23 clinical examinations for rotator cuff tears and found
that supraspinatus weakness, weakness of external rotation and impingement were the most
useful indicators. If all three signs are positive,
or if two signs are positive and the patient is at
least 60 years old, the chance of partial- or fullthickness rotator cuff tear is 98%.
Radiographs of the shoulder may show spur
formation on the undersurface of the acromioclavicular joint or a type III acromion, in which
the anterior aspect of the acromion is hooked
inferiorly and best seen on a supraspinatus outlet
view (a modified Y view). Type III acromion has
been associated with a higher prevalence of rotator cuff tears.
Murrell GA, Walton JR. Diagnosis of rotator
cuff tears [letter]. Lancet 200 1;357:769–770.
308
Shoulder/Elbow II Structured SBA
Walton JR, Murrell GA. Clinical tests diag-
nostic for rotator cuff tear. J Shoulder Elbow
Surg. 2012;13:17–22.
30. Answer A. Arthroscopic cuff repair
The MRI demonstrates a full-thickness tear of
the anterior part of the supraspinatus tendon.
This should be amenable to surgical repair.
Most studies show that both arthroscopic and
mini open cuff repair techniques improve functional outcome, improve pain scores and shoulder range of movement. Reported advantages of
arthroscopic rotator cuff repair include quicker
recovery from surgery, less extreme pain scores,
lower re-tear rates and better patient satisfaction.
The other treatment options deal with irreparable tears. Superior capsule reconstruction is a
newish technique that involves either a fascia lata
autograft or dermal allograft. A dermal allograft
limits donor site morbidity. In a subset of
patients with rotator cuff tears, the glenohumeral
joint has minimal degenerative changes, and the
rotator cuff tendon is either irreparable or very
poor quality and unlikely to heal. Reverse shoulder arthroplasty (RSA) could be considered for
these patients despite the lack of glenohumeral
arthritis. However, due to concerns with functional outcome of RSA in a younger patient
group, complication rates and co ncerns about
implant longevity, a superior capsular reconstruction (SCR) is a possible alternative.
31. Answer E. Total shoulder arthroplasty (TSA)
The patient’s radiographs demonstrate advanced
glenohumeral osteoarthritis. The history implies a
functioning rotator cuff; she has good overall
health and will place acceptable functional
demands onthe shoulder. As such, a total shoulder
arthroplasty is the most suitable option for her.
On examination an irreparable or chronic
rotator cuff deficiency in an elderly patient
would require a reverse shoulder arthroplasty
(RSA). TSA results in significantly greater pain
relief and internal rotation than shoulder hemiarthroplasty but is as sociated with increased cost,
operating time and blood loss.
For low-demand patients lacking a functioning rotator cuff, hemiarthroplasty will relieve
pain but is unlikely to improve functional range
of movement.
Humeral head resurfacing is reserved for
concentric osteoarthritis without glenoid erosions or rotator cuff damage. It has high rates
of revisions at medium term due to glenoid attrition and rotator cuff problems.
A stemless shoulder prosthesis has its fixation
in the metaphyseal part of the humerus, making
it possible to restore shoulder joint anatomy
without dissecting the diaphyseal part. This is a
relatively new implant showing good early results
but with no long-term follow up.
32. Answer C. The carrying angle is defined as the
angle between the long axis of the extended and
supinated forearm as it lies lateral to the long
axis of the arm
This SBA is testing biomechanics of the elbow.
The carrying angle increases with age.
The opposite is true. The carrying angle
decreases with elbow flexion.
The carrying angle is greater in females than
males. The normal carrying angle is 11–14° in
males and 13–16° in females.
Normal carrying angle is 10– 15°.
The carrying angle allows the forearm to clear
the hip when the upper limb is swinging, such as
during walking. The axis of the arm is defined by
the lateral border of the cranial surface of the
acromion to the midpoint of the lateral and medial
epicondyles of the humerus. The axis of the forearm is defined by the midpoint of the lateral and
medial epicondyles of the humerus tothe midpoint
of the distal radial and ulnar styloid processes.
33. Answer D. Medialising the joint centre of rota-
tion increases the torque on the glenoid bone–
implant interface and decreases the lengths of
the deltoid abductor moment arm
Increasing numbers of RTSA are being performed and indications for use are widening.
As such, the biomechanics of RTSA is classic T
+O basic science material.
Lateralising the joint centre of rotation increases
the torque on the glenoid bone implant–interface
and decreases the lengths of the deltoid abductor
moment arm. Placing the centre of rotation further
distal (inferior) also has an advantage in that it
tensions the deltoid and improves the clearance of
the humeral prosthesis inferiorly, reducing the incidence of inferior impingement and notching.
309
Jonny Kent and Faizan Jabbar
34. Answer A. Allowing inferior overhang of the
glenosphere
Figure 14.8 Biomechanics of the RTSA
This SBA concerns scapula notching. Scapular
notching is thought to result from mechanical
impingement of the superomedial humeral prosthesis against the inferior scapular neck during
adduction (Figure 14.8). Rates of scapular notching are significant, occurring in up to two-thirds
of patients within 2 years of reverse shoulder
arthroplasty.
Eccentric glenosphere positioning resulting
in inferior overhang of the glenosphere leads to
the creation of a space between the scapular neck
and the glenosphere. This decreases the incidence
of scapular notching and reduces impingement
of the humeral tuberosity against the acromion,
resulting in increased range of motion.
Inferior inclination of the glenoid component,
option D, has shown contradictory results.
Cadaveric studies demonstrated increased
impingement-free range of movements following
RTSA that has not been validated by clinical studies.
Scapula notching is reduced by the following:
Eccentric (inferior) glenosphere position.
Increased lateral offset.
Increasing inclination (neck–shaft angle) of the
humeral component.
Known predictors of scapular notching can be
categorised into the following:
1. Patient-specific risk factors
Rotator cuff tear arthropathy with a
narrowed acromiohumeral distance
(incidence 76% compared with 38% in posttraumatic cases).
Glenoids with superior erosion (type E2
glenoid wear), and MRI evidence of grade 3 or
4 fatty infiltration of the infraspinatus muscle.
2. Surgical technique
Anterosuperior approach has a higher
incidence of scapular notching than
deltopectoral interval (86% versus 56%).
Increased risk of malpositioning with glenoid
caudal or cranial tilt.
Neutral or sup eriorly tilted baseplates
increase the risk of scapular notching
compared with inferior glenoid tilt.
Allowing inferior overhang of the
glenosphere improved impingement-free
adduction and abduction angles.
Baseplates implanted with a slight inferior
tilt had the most compressive forces under
the baseplate during loading with the least
amount of tensile forces.
35. Answer E. Supraspinatus, infraspinatus and
teres minor
‘Hornblower’s’ sign occurs due to significant
weakness in shoulder external rotation, specifically infraspinatus and teres minor . When the
patient is asked to bring both hands to the
mouth, they have difficulty doing so on the side
with the rotator cuff injury. Instead, they compensate by abducting the injured arm and
allowing it to fall into internal rotation, mimicking the position of a Hornblower.
The classic reference for this is Walch et al.
(1998) where a Hornblower’s sign indicated an
irreparable tear of infraspinatus and teres minor.
The companion sign is the ‘dropping’ sign. To
perform this, the arm is held at the side (0°
abduction) with the elbow flexed to 90°. The
examiner passively externally rotates the arm to
45° and the patient is asked to hold this position.
The dropping sign is positive when the patient is
unable to do so, and the arm returns to neutral.
The dropping sign indicated an irreparable infraspinatus tear; infraspinatus is the strongest external rotator when the arm is held by the side.
Walch G, Boulahia A, Calderone S,
Robinson AH. The ‘dropping’ and ‘ horn-
blower’s’ signs in evaluation of rotator-cuff tears.
J Bone Joint Surg Br. 1998;80:624–628.
310
Shoulder/Elbow II Structured SBA
36. Answer D. Parsonage–Turner syndrome
Each answer is possible and valid if we were to
only look at specific parts of the history. A history of diabetes and the severity of symptoms
raise the suspicion of adhesive capsulitis and
septic arthritis. Entrapment of the suprascapular
nerve in the supra-glenoid notch is associated
with labral tears and would lead to wasting of
supraspinatus and infraspinatus. Cervical radiculopathy (C5–6) should be on the list of differential diagnosis for those presenting with rotator
cuff weakness and atrophy.
The discerning features are the near full range
of passive movement (suggesting minimal pain
inhibition) and unremarkable inflammatory
markers. This helps us exclude adhesive capsulitis
and more importantly, septic arthritis. Diabetes in
this case has been used as a distractor for adhesive
capsulitis. Cervical disc prolapse and associated
radiculopathy is also unlikely as there is no mention of neck pain nor radiculopathy symptoms.
This leaves entrapment neuropathy and
Parsonage–Turner syndrome (PTS). The acute
onset and severity of pain coupled with risk
factors (middle aged, male, post-surgery) make
PTS the most likely diagnosis. PTS (also call ed
idiopathic brachial plexopathy) is thought to be
an immune-mediated disorder, characterised by
acute, debilitating unilateral shoulder pain that is
followed by paresis and atrophy of the shoulder
girdle. It is known to present following surgery,
often unrecognised and diagnosed late. The
sudden loss of strength may not be noted immediately as the patient is reluctant to use the limb
due to severe pain. Within a month, the weakness is usually fairly obvious and atrophic
changes identifiable. Scapulothoracic nerve
involvement, innervating the serratus anterior,
may present with scapular winging. This could
be missed if the patient is not adequately exposed
during examination.
37. Answer B. Close outpatient follow up
Osteonecrosis is a very rare complication
following paediatric fracture dislocations of the
shoulder. Studies have demonstrated that revascularisation at long-term follow up occurs in the
majority of cases without surgical intervention.
Therefore, the most appropriate answer for this
case is b.
Wang P Jr et al. Salter-Harris type III
fracture-dislocation of the proximal humerus. J
Pediatr Orthop B. 1997;6:219–222.
38. Answer D. Infection
Current evidence suggests the commonest mode
of early failure following semi-constrained total
elbow arthroplasty is infection. Apart from bushing failure, which is uncommon , the rest of the
options are likely to occur in the intermediate/
late term post-operatively.
Throckmorton T, Zarkadas P, Sanchez-
Sotelo J, Morrey B. Failure patterns after linked
semiconstrained total elbow arthroplasty for
posttraumatic arthritis. J Bone Joint Surg Am.
2010;92:1432–1441.
39. Answer E. Suprascapular nerve
Establishing a posterior portal can put the axillary nerve and suprascapular nerve at risk. If the
portal is established too inferior the axillary
nerve is at risk vs a medial placement which runs
the risk of a suprascapular nerve injury.
The musculocutaneous nerve is at risk if the
anterior portal is positioned too inferior. The
phrenic nerve is at risk if an interscalene block
is performed.
40. Answer D. Spinoglenoid notch and ligament
This stem is testing your anatomical kno wledge
of the suprascapular nerve and potential compression sites. The stem describes a weakness of
infraspinatus and isolated infraspinatus atrophy
therefore the compression is likely at the distal
compression site at the spinoglenoid notch.
Supraspinatus strength would likely be normal
in this case.
41. Answer D. 30° forward flexion, 30°abduction,
30° internal rotation
The optimal position of fusion to maximise
activities of daily living: think 30-30-30. 30° forward flexion, 30° abduction and 30° internal
rotation. This will allow the patient to bring their
hand to mouth and allow for self-care.
42. Answer C. Lateral pivot shift-test
This stem describes lateral ulnar collateral ligament injury (PLRI). The lateral pivot shift test is
performed usually with the patient supine,
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Jonny Kent and Faizan Jabbar
shoulder and elbow flexed to 90° with forearm
supinated. While bringing the arm into extension
a valgus stress is applied, a positive test would
demonstrate prominence posterolate rally with
skin dimpling. One may also elicit a palpable
clunk as there may be subluxation of the radial
head. Considering the prone push up test with
the elbow flexed at 90° and forearm supinated, as
the patient attempts to push up the patient would
experience apprehension with a PLRI injury
(87.5% sensitivity in isolation). Cozen’s test is a
provocation test for lateral epicondylitis. Varus
stress testing is applicable for assessing varus
instability. Answer D describes provocation
testing for medial epicondylitis. Hyperpronation
testing is specific for varus posteromedial rotatory instability.
Karbach LE, Elfar J. Elbow instability: anat-
omy, biomechanics, diagnostic maneuvers, and
testing. J Hand Surg Am. 2017;42:118–126.
O’Driscoll SW, Bell DF, Morrey BF.
Posterolateral rotatory instability of the elbow. J
Bone Joint Surg Am. 1991;73:440–446.
43. Answer B. Associated greater tuberosity
fracture
This stem is testing one’s knowledge of the
‘instability severity index score’ described by
Balg and Boileau (2007). They prospectively analysed patients who underwent an arthroscopic
Bankart repair for recurrent anterior shoulder
instability, specifically identifying predisposing
factors for recurrent post operative instability.
The following risk factors were identified and a
scoring system applied. A score 6 points demonstrated an acceptable recurrence risk of 10%
recurrence with arthroscopic stabilisation, while
a score >6 points demonstrated an unacceptable
recurrence risk of 70% and an open surgical
stabilisation should be advised (Laterjet
procedure).
Balg F, Boileau P. The instability severity
index score: a simple pre-operative score to select
patients for arthroscopic or open shoulder stabilisation. J Bone Joint Surg Br. 2007;89:1470–1477.
44. Answer A. Syringomyelia
Syringomyelia causes 25% of Charcot joints of
the upper extremity. This is a rare condition with
Table 14.1 Instability severity index score
Factor Points
Age at Surgery
20 2
>20 0
Degree of sport participation
Competitive 2
Recreational or none 0
Type of sport
Contact or forced overhead 1
Other 0
Shoulder hyperlaxity
Hyperlaxity 1
Normal 0
Hill-Sachs lesion on AP radiograph
Visible on external rotation 2
Not visible on external rotation 0
Glenoid loss of contour on AP radiograph
Loss of contour 2
No lesion 0
limited evidence within the literature, however
one should be aware of the potential differentials
and assessment and further management of
neuropathic joint prese ntation. This is dependent
on the underlying condition and clin ical assessment. One should evaluate for a syrinx with
MRI. There is an association with Arnold
Chiari malformation as the most common cause
of syringomyelia. Hansen’s disease is the next
most common cause of upper limb neuropathic
arthropathy. In the presence of a syrinx, one
should consult with the neurosurgical team for
consideration of surgical decompression. Elbow
arthrodesis is predominantly a salvage procedure
once conservative options have failed. Total
elbow arthroplasty is generally contraindicated
for an underlying Charcot joint.
Jen CL, Tan JC. Neuropathic arthropathy of
the elbow treated with double-plate arthrodesis
and resection site bone graft. Shoulder Elbow
2016;8:48–53.
312
Section 3
Chapter
15
Trauma
Trauma I Structured SBA
Tim Brock and Rishi Dhir
TRAUMA I STRUCTURED SBA QUESTIONS
1. A 75-year-old female presents with a shoulder
injury following a fall. Radiographs show a fractured proximal humerus (Figure 15.1).
According to Hertel’s study, which of the
following is NOT a good predictor of humeral
head ischaemia?
A. Basic fracture pattern
B. Calcar fragment <8mm
C. Glenohumeral dislocation
D. Integrity of the medial hinge
E. Length of the metaphyseal head extension
2. A 35-year-old male sustains a closed proximal
tibial fracture and elects to undergo intramedullary nailing. His radiographs are shown in Figure
15.2.
Which of the follow ing surgical techniques is
used to prevent a valgus and procurvatum
deformity?
A. Place a coronal Poller (blocking) screw in the
anterior half of the distal aspect of the proximal fragment
B. Place a sagittal Poller (blocking) screw on the
medial convex side of the distal aspect of the
proximal fragment
C. Suprapatellar nailing
D. Use of a nail with a more distally based bend
E. Using a more medial entry point
3. While playing rugby , a 30-year-old male sus-
tained the injury seen in Figure 15.3, taken on
presentation to the ED.
Which of the following is true?
A. If reduced and stable, it does not require
extension splinting
B. It can lead to a Swan neck deformity
C. It has a positive Elson test
D. It is associate d with a volar plate injury
E. It is the most common type of PIPJ
dislocation
4. A 40-year-old roofer fell 10 feet off a ladder onto
his left foot. Radiograph and CT scan are shown
in Figure 15.4.
Regarding this injury, which of the following is
true?
(a) (b)
Figure 15.1 (a) Anteroposterior (AP)
and (b) lateral scapula view radiographs
proximal humerus
313
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