Perilunate instability - Mayfield classification of carpal instability
Mayfield et al. described in 1980 the following four stages of progressive carpal instability.
| Stage | Description |
|---|---|
| Stage I | scapholunate dissociation: dorsal dislocation of the proximal scaphoid pole in the radiocarpal joint (rotatory subluxation of the scaphoid) with disruption of the dorsal scapholunate ligament leads to widened scapholunate distance (Terry Tomas sign) on radiograph |
| Stage II | perilunate dislocation: midcarpal instability between the lunate and the capitate - the scaphoid and distal row complex dislocates dorsally relative to the lunate |
| Stage III | midcarpal dislocation: fracture of the triquetrum or rupture of the lunotriquetral ligament |
| Stage IV | lunate dislocation: palmar rotatory dislocation of the lunate into the carpal canal - "tipped teacup" appearance |
References:
1. Schmitt R, Lanz U. Diagnostic Imaging of the Hand. Thieme; 2008.
2. Mayfield JK, Johnson RP, Kilcoyne RK. Carpal dislocations: pathomechanics and progressive perilunar instability. J Hand Surg Am. 1980 May;5(3):226–41.
3. Bellot F, Tran Van F, Leroy N, Blejwas D, Mertl P. [Peri-lunate wrist dislocation: long-term outcome]. Rev Chir Orthop Reparatrice Appar Mot. 2003 Jun;89(4):320–32.
4. Wolfe SW, Hotchkiss RN, Pederson WC, Kozin SH. Green’s Operative Hand Surgery E-Book: Expert Consult: Online and Print. Elsevier Health Sciences; 2010.
Updated 5/12/2013 13:17 by Lambert