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Trauma

Elbow dislocation and chronic instability

Simple elbow dislocation, origins of instability, Morrey staging, posterolateral fracture dislocation.

26 questions 4 source pages 2 images

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26 questions
Q1What is the acute management of a simple elbow dislocation?📷▸
Xray showing simple elbow dislocation
Xray showing simple elbow dislocation
  • Stabilise patient and rule out other injuries
  • Rule out local complications: open wound, compartment syndrome, NV injury
  • Analgesics, immobilise
  • Reduction + immobilise +/- operation
Q2Describe the reduction technique for elbow dislocation.▸
  • Under conscious sedation: traction, supination, direct manipulation
  • Align forearm and humerus; traction with elbow flexed 90 degrees; direct pressure over olecranon; +/- supination
  • Parvin's method: prone, traction over wrist for a few minutes, then lift arm
Q3What do you check on post-reduction fluoroscopy?▸
  • Joint congruity - drop sign = pseudosubluxation >=4mm ulnohumeral displacement (interposed soft tissue/instability)
  • Range of stable reduction
  • Collaterals - varus/valgus stress; pMCL only stable in pronation, aMCL+pMCL unstable in pronation; repeat in full extension and 30 degrees flexion
  • Rotatory instability - lateral pivot shift, PL drawer, chair sign, table to relocation test
Q4What is the management if the joint is congruent and stable?▸
  • Immobilise for 2 weeks + early mobilisation
  • Recurrence <2%, loss of terminal extension 5-15 degrees
  • Stability is better in flexion and pronation
  • Rehab: early ROM within 10 days, avoid immobilisation >3 weeks, aim full extension by 8 weeks
Q5Describe PLRI and PMRI.▸
  • Both involve axial load + forearm supination, with valgus stress in PLRI and varus stress in PMRI
  • PLRI sequence: LUCL then pMCL then aMCL (Hori circle) +/- bone injury (coronoid tip, radial head)
  • PMRI sequence: LUCL, aMCL +/- coronoid base/AM facet; radial head usually intact
  • CT/MRI is the gold standard for diagnosis
Q6When do you proceed to open reduction and what are the complications?▸
  • Open reduction +/- repair if failed congruent reduction or unstable (dislocates in splint, dislocates with <30 degree flexion + pronation)
  • Complications: HO, ulnar nerve irritation, OA, instability
Q7How is the lateral pivot shift test performed?▸
  • Forearm supinated, valgus and axial load
  • In extension the radial head is dislocated
  • Toward 40 degrees flexion the triceps reduces the radial head with a clunk
Q8What physical examination tests suggest PMRI?▸
  • Varus/valgus stress with the shoulder in max IR/ER
  • Gravity assisted varus stress: shoulder 90 degrees abduction, elbow flexed and extended - pain on flexion due to lack of medial buttress by LUCL and coronoid
  • Chair test
  • Table top relocation test: radial head subluxes as the forearm presses the table in supination - apprehension relieved by posterior radial head pressure
Q9Where does the MCL originate?▸
  • Anteroinferior portion of the medial epicondyle
  • MCL = medial collateral ligament
Q10Where does the LCL originate?▸
  • Inferior portion of a small tubercle on the lateral epicondyle
  • LCL = lateral collateral ligament
Q11What is the Morrey staging of instability used for and how does it progress?📷▸
Morrey stage of instability used in chronic condition
Morrey stage of instability used in chronic condition
  • Used in the chronic condition
  • Progresses from lateral to medial
  • LCUL --> RCL + capsule --> PMCL --> AMCL
Q12List the structures involved in the Morrey stages of elbow instability, in order.▸
  • 1. LCUL
  • 2. RCL + capsule
  • 3. PMCL
  • 4. AMCL
Q13What are the components of a terrible triad elbow injury?▸
  • Elbow dislocation
  • Radial head fracture
  • Coronoid fracture
  • XR: fragments over the medial epicondyle and sigmoid notch (likely radial head), no soft tissue gas
Q14What initial assessment and management is described for a fracture dislocation of the elbow?▸
  • ATLS protocol, primary and secondary survey, AMPLE history + premorbid status
  • Check NV status and compartments; examine one joint above and below (Essex lopresti)
  • Analgesia with adequate sedation using midazolam and pethidine
  • CR with elbow at 90 degrees flexion + gentle traction and direct olecranon manipulation, then splint
Q15What does Morrey's model describe as the primary static, secondary static and dynamic stabilizers of the elbow?▸
  • Primary static = UHJ, LUCL, MCL
  • Secondary static = RCJ, CEO, CFO
  • Dynamic = anconeus, triceps and biceps
  • Indication for surgery = loss of dynamic and static stabilisers
  • Aim = concentric stable reduction to allow early mobilisation
Q16What definitive planning is required after initial reduction of a terrible triad?▸
  • CT for planning: classify the coronoid fracture (O'Driscoll/Morrey) and radial head fracture (Mason)
  • Indicated for surgical repair and ORIF due to loss of dynamic and static stabilisers
  • Aim: concentric stable reduction to allow early mobilisation
  • Position supine; approach = utility posterior approach
Q17What is the sequence of fixation in operative management of a terrible triad?▸
  • Fix the coronoid first through the radial head fracture window - small, use lasso transosseous repair
  • Fixation or replacement of the radial head or neck
  • Repair the LUCL with suture anchor or fibre tape
  • Test stability; repair MCL via a medial approach if still unstable
  • If still unstable, prepare radial head replacement or apply a dynamic joint distractor (DJD)
Q18Which approach is chosen in a terrible triad and what are the options?▸
  • Posterior utility approach, raising thick flaps on the medial and lateral sides to address the respective pathologies
  • Laterally: Kocher interval (ECU-anconeus), Kaplan interval (ECRB-EDC) or Boyd interval (anconeus and FCU)
  • Kaplan may preserve the remaining lateral ligamentous complex but has more PIN palsy
  • Boyd if there is also an olecranon fracture
  • Key point: watch out for the PIN and radial nerve
Q19How can exposure be improved during the posterior utility approach?▸
  • Release the ECRB along the supracondylar ridge
  • Release some of the supinator distally
Q20What medial approaches are available in a terrible triad and what are their pros and cons?▸
  • Hotchkiss (flexor pronator mass, PL-FCU), split FCU, or Taylor Scham (elevate the entire flexor pronator mass from posterior to anterior)
  • Watch the medial antebrachial cutaneous nerve on skin incision; deep, watch the ulnar nerve
  • Hotchkiss: good access to the anterior elbow capsule, BUT limited access to the medial facet of the coronoid and poor access to its base
  • Split FCU probably most versatile in terrible triad (addresses base and anteromedial facet)
  • Taylor Sham best for accessing the base
Q21How can PIN injury be avoided during the Kocher approach in terrible triad surgery?▸
  • Fully pronate the forearm
  • Avoid incising the capsule too anteriorly (PIN lies over it)
  • Avoid dissection distal to the annular ligament (PIN lies within supinator)
  • Do not place retractors around the radial neck
Q22When is radial head ORIF preferred over replacement, and when is replacement indicated?▸
  • ORIF best reserved for non-comminuted fractures with 3 or fewer fragments
  • Attempted fixation of more comminuted fractures is prone to fixation failure and nonunion (Ring and Jupiter JBJS 2002)
  • Replacement indications: Mason III + >3 articular fragments
  • Replacement also for an unstable elbow (Mason IV / Essex-Lopresti injury)
  • Prepare radial head replacement if still unstable after MCL + LUCL repair and ORIF
Q23What did the Sun 2016 meta-analysis find comparing arthroplasty with ORIF for radial head fractures?▸
  • Metaanalysis by Sun 2016 Eur J ortho trauma: arthroplasty yielded higher satisfaction, better elbow scores, shorter surgical time and lower incidence of recurrent instability
  • Replacement has better ROM and is a faster operation
  • ORIF has a higher reoperation rate and higher complication rate
  • BUT functional score is similar
Q24Describe the safe zones for applying a dynamic joint distractor (DJD).▸
  • Distal 1/3 humerus: anterolateral or posterolateral
  • Middle 1.3 humerus: anterolateral (middle third of the humerus)
  • Proximal forearm: lateral/posterolateral proximal and middle 1/3 ulna, neutral rotation
  • Axis guidewire: lateral just distal to lateral epicondyle, medial slightly anterior and distal to medial epicondyle; place hinge over the guidewire
Q25What rehabilitation and prophylaxis follow fixation of a terrible triad?▸
  • Long arm slab in pronation for 2 weeks
  • Then progressive ROM exercises, starting with active assisted FE and SP
  • HO prophylaxis
Q26For a transolecranon fracture dislocation, which radiographic parameters must be restored?▸
  • PUDA (proximal ulnar diaphyseal angle): 8-10 degrees
  • OW (olecranon width)
  • ODA (olecranon diaphyseal angle): 23 degrees between the olecranon tip and the diaphysis
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