Multi-ligamentous injury of the elbow with instability

Case contributed by Joachim Feger
Diagnosis certain

Presentation

Recurrent instability now pain and swelling of the left elbow after minor trauma during a football game

Patient Data

Age: 20 years
Gender: Male

Findings:

  • elbow joint effusion

Bones:

  • posterolateral  subluxation of the radial head in relation to the capitellum
  • mild bone marrow edema of the anterior and posterior radial head and the posterior capitellum
  • peripherally sclerosed osseous fragment with mild proximal marrow edema distal  to the medial (ulnar) epicondyle, and several smaller ones posterior to the capitellum consistent with old avulsions

Ligaments:

  • partial tear of the lateral ulnar collateral ligament (LUCL)
  • partial tear of the radial collateral ligament  (RCL)
  •  a tear of the posterior bundle of the ulnar collateral ligament (UCL)

Muscles and tendons:

  • a musculotendinous strain of the extensor carpi ulnaris origin
  • myotendinous injury of the flexor digitorum superficialis muscle
  • myotendinous injury of the brachialis muscle
  • a tear of the insertion of the anconeus muscle
  • unremarkable distal biceps tendon

Impression:

  1. Multi-ligament injury of the elbow joint with posterolateral subluxation of the radial head and Osborne-Cotterill lesion compatible with a posterolateral rotatory instability pattern.
  2. Myotendinous injuries of the brachialis and flexor digitorum superficialis muscle.
  3. Old avulsion fracture of the medial epicondyle suggestive of an old elbow injury possibly an old dislocation.

old X-ray 5 years earlier

x-ray
  • anterior elbow dislocation
  • large peripherally sclerosed fragment distal to the medial epicondyle
  • several small fragments posterior to the distal humerus capitellum

Key findings:

  • increased radiocapitellar joint space (red double arrow)
  • bone bruise of the posterior capitellum (red arrow) and anterior radial head (red arrowhead)
  • bone bruise of the posterior radial head (orange  arrowhead)
  • small peripherally sclerosed fragments posterior to the capitellum (red dotted circle) - old Osborne-Cotterill lesion
  • myotendinous injury of the brachialis muscle (light blue arrow) and the flexor digitorum superficialis origin (light blue arrowhead)
  • the humeral insertion of the radial collateral ligament (purple arrowhead) and the lateral ulnar collateral ligament (dark blue arrowhead) are not readily identified, instead, there is some ill-defined tissue
  • the posterior part of the ulnar collateral ligament is torn
  • the anterior part of the ulnar collateral ligament (green arrow) is attached to an old medial avulsion fragment, intact distal lateral ulnar collateral ligament (LUCL)
  • anterior radiocapitellar shift - the distance between the radial axis and the midpoint of the capitellum > 2mm
  • ulnohumeral joint asymmetry

Case Discussion

This case illustrates MRI findings of recurrent instability in an elbow joint:

The posterolateral subluxation of the radial head in relation to the capitellum, the bone bruises of the posterolateral capitellum and the anterior radial head indicate a posterolateral rotatory instability pattern of previous elbow dislocation 2-7, which we found proof of merely by chance in form of old x-ray films.

The diagnosis is further supported by the Osborne-Cotterill lesion, the proximally torn radial collateral ligament complex (lateral ulnar collateral ligament and radial collateral ligaments).  

The injury of the ulnar collateral ligament complex and flexor digitorum superficialis point towards an advanced grade of posterolateral rotatory instability and an additional valgus instability 3-5.

Treatment of lateral collateral ligament injury depends on clinical symptoms. In a young patient with a posterolateral rotatory instability, it is mainly surgical, especially if recurrent, and focused on stabilizing the ulnohumeral joint by reconstruction of the lateral ulnar collateral ligament 7-9.

Because of the current COVID-19 pandemic, the patient chose not to have surgery for the time being.

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