There are a number of tests and actions that can be performed when a patient is suspected of having osteoarthritis caused by SLAC or SNAC.SLAC:

Tenderness 1 cm above Lister’s tubercleTests:

Watsons test
Finger extension testSNAC:

Tenderness at the anatomical snuff box
Painful pronation and supination when performed against resistance
Pain during axial pressure

X-rays
Osteoarthritis between the radius bone and the carpals is indicated by a radiocarpal joint space of less than 2mm.SLAC

Because SLAC results from scapholunate ligament rupture, there is a larger space between the two bones, also known as the Terry Thomas sign. Osteoarthritis and a space larger than 3 mm is suspicious and a space larger than 5 mm is a proven SLAC pathology. Scaphoid instability due to the ligament rupture can be stactic or dynamic. When the X-ray is diagnostic and there is a convincing Terry Thomas sign it is a static scaphoid instability. When the scaphoid is made unstable by either the patient or by manipulation by the examining physician it is a dynamic instability.SNAC
In order to diagnose a SNAC wrist you need a PA view X-ray and a lateral view X-ray. As in SLAC, the lateral view X-ray is performed to see if there is a DISI.Computed tomography (CT) or Magnetic Resonance Imaging (MRI) are rarely used to diagnose SNAC or SLAC wrist osteoarthritis because there is no additional value. Also, these techniques are much more expensive than a standard X-ray. CT or MRI may be used if there is a strong suspicion for another underlying pathology or disease.
Treatment
Post-traumatic wrist osteoarthritis can be treated conservatively or with a surgical intervention. In many patients, a conservative (non-surgical) approach is sufficient. Because osteoarthritis is progressive and symptoms may get worse, surgical treatment is advised in any stage. Stage I
For stage I, normally, nonsurgical treatment is sufficient. This type of therapy includes the use of splint or cast immobilization, injections of corticosteroid in the pain causing joints and the use of a systemic non-steroidal anti-inflammatory drug to reduce pain and improve the functional use of the affected joint. However, the amount of pain that can be suppressed by nonsurgical therapy is limited and with the progression of the wrist osteoarthritis surgical treatment is inevitable.In stage I surgical treatment often consists of neurectomy of the posterior interosseous nerve and is often combined with other procedures. In the case of a SLAC, the scapholunate ligament can be reconstructed in combination with a radial styloidectomy, in which the radial styloid is surgically removed from the distal radius. In the case of a SNAC, the scaphoid can be reconstructed by fixating the scaphoid with a screw or by placing a bone graft (Matti-Russe procedure) to increase the stability of the scaphoid. Stage II
In the treatment of stage II wrist osteoarthritis, there are two treatment options that have proved to be most successful. The first treatment option is proximal row carpectomy. During this surgical intervention the proximal row of the carpal bones is removed (scaphoid, lunate, triquetrum, pisiform).