Background: Scaphotrapeziotrapezoid (STT) fusion, is a motion preserving limited wrist arthrodesis aiming to achieve a painless and stable wrist joint. The aim of the current study was to assess outcome STT fusion without lunate excision in management of stage IIIB Kienbock’s disease using miniplate and screws.
Methods: All 36 patients were males with an average age 43 years. All patients were evaluated clinically (pain, range of motion and grip strength) and radiologically by x-rays and CT scans (for measurement of carpal height ratio (CHR), ulnar carpal distance ratio (UDR) and radioscaphoid angle (RSA)). Functional evaluation was carried out using the modified Mayo wrist score.
Results: The mean follow-up period was 30 months. The averages VAS score and grip strength improved significantly. The postoperative arc of extension/flexion of the wrist was 60% of the contralateral side and 85% of preoperative range, while the arc of ulnar and radial deviation was 52% of the contralateral side, 65% of pre-operative range. The average Mayo score significantly improved from 45 to 75 postoperatively. All patients achieved union in an average of 8.2 weeks except in one patient. No evidence of radioscaphoid arthritis was observed till the last follow-up. No cases of hardware failure or soft tissue impingement were recorded.
Conclusion: STT fusion without lunate excision can prevent progressive carpal collapse in Kienbock’s disease stage IIIB without radioscaphoid arthritis. The procedure provides pain relief, preserves an acceptable range of wrist motion and improves grip strength. The use of miniplate and screws allows rigid fixation with high rate of union. However STT fusion is a salvage procedure and further research is necessary to find a proper treatment which preserves the normal anatomy of the wrist. |
