EXTENSOR TENDON RUPTURE (VAUGHAN-JACKSON SYNDROME)

Vaughan-Jackson syndrome, as the eponym suggests, was first described by OJ Vaughan-Jackson in elderly laborers with degenerative arthritis of the distal radioulnar joint (DRUJ). Ten years later, he described the process of attritional rupture of the digital extensor tendons in the rheumatoid hand, with which his name has become associated. Rheumatoid arthritis (RA) is the most common underlying etiology of tendon rupture in the hand and wrist. As the tendons generally rupture in an ulnar-to-radial direction, the condition is also frequently referred to as Caput Ulnae syndrome.

Related Anatomy

• Extensor tendons of the fingers
• DRUJ
• MP joints of fingers

Pathophysiology

• In RA, tendons may subluxated or dislocate dorsally due to the loss of normal supporting structures, which in turn, leads to gradual attrition of tendons on the ulnar head.
• Tendon wear may be exacerbated by osteophytes and sharp prominences resulting from primary or secondary degenerative changes of the bone.
• Rheumatoid tenosynovitis affects tendons and interferes with normal blood supply to the tendons.

Incidence and Related Conditions

• Vast majority of tendon ruptures occur in patients with RA, and the incidence of extensor tendon involvement is 10–15 times that of the flexor tendon involvement.
• In patients with RA, tendon ruptures have been seen in the disease for ≤2 years to as long as 25 years; in most series, RA has been present for 10–15 years.

Differential Diagnosis

• Extensor tendon subluxation at the metacarpophalangeal (MP) joint
• MP joint subluxation or dislocation
• Posterior interosseous nerve (PIN) palsy

Vaughan-Jackson (Caput Ulna) Syndrome is rupture of the extensor tendons usually starting with the extensors to the fifth finger and ring finger. Osteoarthritis or in the past commonly Rheumatoid Arthritis causes excessive dorsal tenosynovitis and DRUJ degenerative changes which can attritionally rupture the extensor tendons. The EDM and EDC V and IV which are immediately dorsal to the deformed and dorsally subluxating distal ulna are most at risk. There are three suggested causes for the extensor tendon rupture: 1. The damaged sharp edges of the dorsally displaced head of the distal ulna cut the tendons by repeated rubbing of the tendons over the sharp edges which also ruptures the dorsal capsule of the DRUJ. 2. The dorsal tenosynovitiis directly attacks and weakens the extensor tendons until they rupture under the ordinary load of finger extension. 3. In the case of Rheumatoid Arthritis rheumatoid nodules can develop in the substance of the extensor tendon and destroy the tendons structural integrity.