Vascularized Bone Grafting for Scaphoid Nonunion with Humpback Deformity: The Surgical Technique

Abstract

Background Scaphoid nonunion with humpback deformity and avascular necrosis (AVN) is a challenging problem. Correction of dorsal intercalated segment instability (DISI) requires grafting of a large and hard vascularized bone segment onto the volar side of the scaphoid. Purposes We have been treating the patients with one-incision vascularized bone grafting technique for scaphoid nonunion to improve blood supply and correct humpback deformity. We evaluated these cases retrospectively to the surgical efficacy of our procedure. Methods We harvested vascularized bone from the dorsal side of the radius using the method by Zaidemberg et al and inserted the cortical aspect into the scaphoid volar side using a direct lateral approach. Totally, 11 patients (nine males andtwo females) with a mean age of 40 years were recruited for this study. The mean time from fracture to treatment was 6 years and 3 months. The mean preoperative radiolunate angle was 25 degrees. All the patients showed AVN of the proximal scaphoid on T1-weighted images. An averaged follow-up period was 2 years and 3 months. Results Postoperative computed tomography revealed bony union in 10 patients (91% of union rate) with a mean modified Mayo'swrist score of 88 points (range, 75-100 points) and a mean disabilities of arm, shoulder, and hand (DASH) score of 4 points (range, 0-20 points). The mean radiolunate angle was corrected from 25 to 5 degrees. No adverse events were observed, except temporary mild paresthesia of the radial nerve territory in two patients. Conclusion This technique effectively corrected DISI in patients with scaphoid nonunion accompanied by humpback deformity and AVN.

Keywords: direct lateral approach; humpback deformity; radial approach; scaphoid nonunion; vascularized bone graft.

Fig. 1

Schema of our technique. ( A ) Curved skin incision on the radial side of the wrist. We elevated the harvesting bone pedicled from the 1, 2 intercompartmental supraretinacular artery and detached the joint capsule from the styloid to the volar side. ( B ) We cut the tip of the radial styloid, excised the volar part of the scaphoid nonunion, and inserted harvested vascularized bone by rotating the cortical aspect of bone to the volar side.

Fig. 2

intraoperative findings. ( A ) Skin incision. ( B ) Identified 1,2-ICSRA. ( C ) Turning the pedicled bone after harvesting. ( D ) Creating cavity on the scaphoid (arrow) ( E ) Inserting the vascularized bone onto the volar side. An arrow indicated pedicle. ICSRA, intercompartmental supraretinacular artery.

Fig. 3

Preoperative images. ( A1 ) Preoperative anterolateral radiograph. ( A2 ) Preoperative lateral radiograph. Preoperative CT scan:( B1 )coronal, ( B2 ) sagittal on the scaphoid, and ( B3 ) sagittal on the lunate. ( C1 ) Preoperative T1-weighted magnetic resonance imaging. ( C2 )Preoperative T2-STIR image postoperative. CT, computed tomography. STIR, short TI inversion recovery.

Fig.4

Postoperative images. ( A1 ) Postoperative anterolateral radiograph. ( A2 ) Postoperative lateral radiograph. Postoperative CT scan:( B1 )coronal, ( B2 ) sagittal on the scaphoid, ( B3 ) sagittal on the lunate.