Retrograde percutaneous screw fixation for scaphoid type II non-union in Schernberg zones 2 to 4: a series of 38 cases.

Regardless of the treatment used, 25 to 45% of scaphoid fractures do not heal. Open surgery compromises vascularization and destabilizes ligament attachments. The aim of this retrospective study was to assess the value of retrograde percutaneous screw fixation of Alnot stage IIA and IIB scaphoid non-union in Schernberg zones 2 to 4. This series included 38 patients with a mean age of 31 years. Based on the Alnot classification, there were 16 stage IIA non-unions (12 in zone 3 and 4 in zone 2 according to the Schernberg classification) and 22 stage IIB non-unions (9 in zone 3 and 13 in zone 2). The time elapsed between the initial trauma and the surgical treatment was 10 months on average. Percutaneous retrograde fixation was performed with a cannulated 2.7mm compression screw. At 25 months follow-up, 31 of the non-union cases had healed (81.6%), of which 14 were stage IIA (87.5%) and 17 were stage IIB (77.3%), after an average 6.3 months. Average pain was 1.6. The average Quick DASH was 17.3/100. Compared to the opposite side, the average range of motion was 84.8% in flexion, 84.7% in extension, 98.9% in pronation, 96.5% in supination, 96.8% in ulnar deviation and 86.4% in radial deviation. The grip strength was 80.4% of the contralateral side. Seven patients did not heal after screw fixation; four of them healed after additional electromagnetic stimulation and three after addition of a vascularized bone graft. Based on this study's results, stage IIA non-unions can heal with simple retrograde percutaneous screw fixation. The same procedure could be enough for stage IIB non-union cases, however we recommend adding a cancellous bone graft by arthroscopy. Open surgery procedures are preferred when percutaneous procedures have failed.