Review Question - QID 211886

The farmer in question has scapholunate advanced collapse wrist (SLAC) with degeneration of the capitate-lunate joint, which is a contraindication for a Proximal row carpectomy (PRC).

Injury of the scapholunate (SL) ligament permanently changes carpal kinematics, as the SL interval widens and the scaphoid flexes. SLAC wrist is also commonly caused by a crystalline arthropathy. The altered carpal kinematics may precipitate a predictable pattern of degeneration; starting at the radial styloid, then in the scaphoid fossa and finally between the capitate and lunate. On physical exam, in addition to pain, loss of motion, and loss of strength; A Watson shift may be appreciated in earlier stages of disease progression. In this maneuver, the scaphoid may be subluxed dorsally with direct volar to dorsal pressure over the scaphoid tuberosity while moving the wrist from an ulnar to radial direction. Treatment depends on the stage of progression with earlier stages managed with scaphoid stabilization and styloidectomy. A PRC is indicated in stage II (scaphoid-scaphoid facet arthritis), and limited or total wrist fusion for stage III (capitate-lunate arthritis).

Mulford et al. performed a systematic review of 52 articles which detailed the surgical treatment of PRC versus 4 corner fusion (4CF) for SLAC and SNAC wrists. The authors reported while both procedures successfully reduced pain and improved grip strength, the PRC provided improved range of motion while reducing potential complications associated with a 4CF, such as non-union or hardware complications. There is a risk of arthritis progression in a PRC, although this is not always symptomatic.

Weiss et al. review osteoarthritis of the wrist, which often follows disruption of the scapholunate ligament, and may ultimately lead to arthritic degeneration. PRC is the surgical option which best preserves range of motion (50-75% of the contralateral wrist) but requires a preserved capito-lunate joint. Arthritis at the CL joint is best treated surgically with a limited carpal fusion (4CF or capitolunate fusion) or a total wrist fusion.

Figure 1 demonstrates a SLAC III wrist with degeneration of the capitoluante joint.

Answer 1: Arthritis between the scaphoid and radial styloid represents SLAC I is not a contraindication to a PRC.
Answer 2: Arthritis between the scaphoid and radius (scaphoid facet) represents SLAC II is not a contraindication to a PRC.
Answer 3: Arthritis between the scaphoid and capitate represents SNAC II is not a contraindication to a PRC.
Answer 4: Arthritis between the scaphoid and lunate represents a typical pattern for neither SLAC nor SNAC.