TRAPEZIECTOMY AND S-QUATTRO APPLICATION – REVIEW OF 39 CASES

Abstract

Numerous procedures have been described for degenerative arthritis of the carpometacarpal joint of the thumb. The sling procedure is technically demanding and involves sacrificing part of a healthy tendon. Silicon arthroplasty is associated with stem fracture and synovitis. We have successfully used external fixation for distraction and correction of adduction deformity following trapeziectomy with S-Quattro (Stockport Serpentine Spring System). Following trapeziectomy specially designed pins are inserted into the base of the 1^st metacarpal and radial styloid and distracted with 2 serpentine springs. The fixator is removed at six weeks and removable thermoplastic splint applied for further 6 weeks.

We reviewed the results of 39 trapeziectomy performed in 32 patients (3 male) with an average follow up of 53 months. ROM, power, pinch, pain score and patient satisfaction were reviewed by an independent hand therapist.

Average functional score was 28. 9 post-op (maximum 30) compared to 20. 7 pre operatively. Mean thumb abduction was 48. 9 and extension 49. 2 degrees which increased from 42. 9 and 43. 8 pre-operatively. Span was 19 centimetres and opposition 9. 26 on the Kapandji scale. Average grip strength was 40 lbs, pinch strength of 6 lbs and key lateral of 9. 5 lbs. Pain score improved from 7. 9 pre-op to 0. 9. There was statistically significant improvement of all functions except span. Long term follow up radiograph showed good maintenance of gap between base of 1^st metacarpal and scaphoid. Three cases had deep penetration of the pins, which required early removal. We now insert padding between the fixator and the spring to avoid deep penetration. One patient had mild RSD and another patient had pain in the distribution of the radial nerve, both of which improved following pin removal.

Application of S-Quattro following trapeziectomy is a simple and quick procedure. It is reasonably well tolerated by patients. Long-term follow-up showed improvement in hand function and good maintenance of gap between base of 1^st metacarpal and scaphoid.