Ortho Case of the Week – Wrist ANSWERS
Case 1: A previously healthy, right handed 52 year old male presents with a chief complaint of right hand pain occurring immediately after a fall on outstretched hand (FOOSH) injury 3 hours prior to arrival.
1. What is your full read of the x-rays below?
Lunate dislocation and ulnar styloid fracture.
On the AP view there is disruption of the normal alignment of the proximal carpal row with the lunate (blue) appearing triangular in shape and superimposed over the capitate (piece of pie sign), with no normal lunocapitate joint space.
Lateral projection confirms ventral dislocation of the lunate (yellow). Note how the alignment of the distal radius (red) and the capitate (blue) are maintained (green line).
X-rays c/o Radiopedia
2. What nerve is most commonly concurrently injured, and how would you test it?
Median nerve. Acute median nerve compression occurs in up to 30% of patients. The median nerve can be tested with sensation to the radial palm and first three digits, and by having the patient make an ok sign.
C/o EMNotebook.org
3. How would you treat this injury if you were in a community ED without an orthopedics service at your beck and call? What splint would you use?
Reduction followed by splinting with sugar tong splint (video). General steps of closed reduction include traction followed by wrist extension, more traction, wrist flexion with volar pressure applied to rearticulate the lunate with the radius.
Case 2: A previously healthy, right handed 45 year old male presents with a chief complaint of right wrist pain occurring immediately after a FOOSH injury just prior to arrival.
1. What is your full read of the x-rays below?
Irregular transverse fracture through the waist of the scaphoid.
Most commonly waist >> distal pole > proximal pole.
2. What is the feared complication from this injury?
Avascular necrosis (incidence estimated at 13-50%).
The major blood supply of the scaphoid is the dorsal carpal branch of the radial artery, which enters scaphoid on the dorsal surface and supplies the proximal 80% of scaphoid via retrograde blood flow. Minor blood supply is from superficial palmar arch of volar radial artery, which enters distal tubercle and supplies the distal 20% of the scaphoid, creating a vascular watershed and poor fracture healing environment.
3. How would you treat it?
Thumb spica splint (video). May be prefabricated or may need to create one.
4. How would you treat the same patient if they had normal x-rays?
Repeat plain films in 7-10 days which should include scaphoid views. The patient should remain in thumb spica splint during this time. If these are negative but clinical suspicion remains high, MRI may be pursued. Alternatively, immediate MRI after point of injury is the most sensitive imaging modality for nondisplaced fractures within the first 24 hours. MRI is also useful in detecting signs of AVN.
Other useful links:
https://wikem.org/wiki/Hand_exam
https://www.orthobullets.com/hand/6034/scaphoid-fracture
https://radiopaedia.org/articles/scaphoid-fracture