Comparison of proximal row carpectomy and midcarpal arthrodesis for the treatment of scaphoid nonunion advanced collapse (SNAC-wrist) and scapholunate advanced collapse (SLAC-wrist) in stage II.

BACKGROUND: Traumatic instability of the proximal carpal row is based either on a scaphoid fracture or a scapholunate dissociation. Long-standing scaphoid nonunion or scapholunate ligament insufficiency may lead to a carpal collapse and subsequent arthrosis. Controversy exists regarding the appropriate salvage procedure for patients with scapholunate advanced collapse (SLAC)- or scaphoid nonunion advanced collapse (SNAC)-wrist in stage II. Proximal row carpectomy (PRC) and midcarpal arthrodesis (MCA) are two commonly used options. The purpose of this retrospective study was to evaluate the functional outcome and pain relief in SNAC-SLAC-wrist stage II after MCA, compared to PRC in a long term follow up.

METHODS: In the MCA group 17 patients, nine SLAC- and eight SNAC-wrists, with an average age of 47 years at surgery and a mean follow up of 42 months were examined. The PRC group consisted of 30 patients, seven SLAC- and 23 SNAC-wrists, with an average age of 39 years at surgery and a mean follow up of 27 months. Active range of motion (AROM) was verified with a goniometer, grip strength was measured with a JAMAR-Dynamometer II. Pain was evaluated by a visual analogue scale from zero to 100 (VAS 0-100) under resting and stress conditions. Patients' upper extremity disability was measured with the DASH questionnaire. Radiographic evaluation was carried out by conventional X-ray to verify bony consolidation.

RESULTS: Mean values of postoperative AROM in extension/flexion was 61 degrees in MCA, and 75 degrees in PRC patients; radial/ulnar deviation was 32 degrees and 33 degrees, respectively. Mean DASH-score was 21 in the MCA and 25 in the PRC group. Pain relief was 54% in MCA and 77% in PRC during resting conditions and 22% and 42% during stress conditions. Static grip strength was significantly higher following MCA than PRC (72% to 50%). Among both the MCA and PRC groups three patients required further treatment with total arthrodesis due to persisting pain or absence of bony consolidation.

CONCLUSION: Our data demonstrate that PRC is more favourable for patients who require less grip strength at work. For patients carrying out heavy manual work we recommend MCA due to the significantly better grip strength postoperatively.