Olecranon bursitis and posterior interosseous nerve entrapment
- student's elbow (olecranon bursitis)
- acute medial epicondylitis
- chronic lateral epicondylitis
- posterior interosseous nerve entrapment at the arcade of Frohse
- a small posterior joint effusion
- bilateral dislocation of the ulnar nerve over the medial epicondyle on elbow extension implying congenital rather than traumatic absence of the Osborn retinacula
The PIN entrapment explains the finger drop and radial deviation of the wrist on extension. The dislocation of the ulnar nerve (a form of cubital tunnel syndrome) and being right-handed may explain the right-sided ulnar neuropathy.
The triceps and biceps tendon insertions were unremarkable as were the anterior joints, median nerve and the anterior, posterior and oblique ulnar collateral ligaments.
In light of the posterior joint effusion (and trauma) an X-ray was performed. It was unremarkable aside from the swelling at the olecranon bursa.
The olecranon bursa was drained the following day and sent for pathology. The results showed that the fluid was blood. No fluid, leukocytes or organisms were detected.