Treatment of Proximal Ulnar Stump after Darrach or Sauvé-Kapandji Procedure by Transfer of Insertion-Released Pronator Quadratus Pedicle.

Treatment of the proximal ulnar stump with the Darrach or Sauvé-Kapandji (SK) procedure remains controversial. Ulnar wrist symptoms can result, and although many surgeons attribute these to ulnar stump instability, they can also be caused by radioulnar convergence or stump irritation. We present a novel surgical method for protecting the proximal ulnar stump and avoiding these complications. Our cases were five men and five women (mean age 72.0 years, range, 34-89). Mean follow-up duration was 41.7 months (range, 6-101 months). Radiological findings were osteoarthritis in five, rheumatoid arthritis of distal radioulnar joint in three, and ulnocarpal abutment syndrome in two. Pronator quadratus (PQ) was released from its insertion on the radius and transferred dorsally to cover the proximal ulnar stump. Postoperative ulnar wrist symptoms such as ulnar stump tenderness, forearm range of motion, and grip strength were compared with contralateral values. Dynamic radioulnar impingement was evaluated by Lee and Scheker's stress roentgenogram. Nine patients completed the Patient Rated Wrist Evaluation (PRWE) at final follow-up. No patients reported ulnar wrist pain or tenderness at the proximal ulnar stump. Postoperative forearm range of motion recovered almost to contralateral values in cases without preoperative forearm contracture. In the two cases with contracture, postoperative pronation and supination recovered to more than their preoperative range. Grip strength averaged 86.4% (range, 66.7-103%) of the contralateral value at final follow-up. Lees and Scheker's stress roentgenogram revealed marked radioulnar impingement in one case, mild impingement in four cases and none in five, yet no patient complained of pain during the maneuver. The mean PRWE score was 34.7 points (range, 0-52.5 points). Insertion-released PQ pedicle transfer is an effective treatment option for the proximal ulnar stump after the Darrach or SK procedure.