First Metatarsophalangeal Joint Fusion with Orthogonal Memory Staple Fixation

Abstract

Category:Midfoot/ForefootIntroduction/Purpose:First metatarsophalangeal joint (MTPJ) fusion is one of the most commonly performed procedure for painful symptomatic arthritis. The implants used for osteosynthesis are variable and depend on surgeon preference. The aim of this paper was to study the outcome of first MTPJ fusion surgery using fixation with orthogonal shape memory alloy (Nitinol) staples.Methods:75 consecutive patients who underwent first MTPJ fusion with orthogonal memory staples were included in the study. All patients underwent surgery using standard surgical technique with fixation of the arthrodesis with two 20 mm shape memory alloy (Nitinol) staples (Memo staples, Ortho Solutions Inc). The first staple placed medially and the second staple placed dorsally in orthogonal plane. The arthrodesis surfaces were prepared and temporarily fixed with K wire. Once the position and bone approximation was confirmed satisfactory under image intensifier guidance, a flat staple bed was prepared with saw blade to make sure the staples are not proud after fixation. All patients also received standard postoperative care with heel weight bearing shoe for six weeks and follow-up at 3,6 and 12 weeks as standard regimen. Patient demography, time to clinical and radiological union, early/late complications, rate of non-union, revision surgery and implant removal were noted.Results:Average age was 64.6 years. 42 patients had severe radiologic arthritic changes while 27 patients had associated moderate to severe hallux valgus deformity. Five patients were known to have inflammatory arthritis. The average follow-up was 18.3 weeks. There were two early complication of superficial infection treated successfully with oral antibiotics. Average clinical union was 7.2 weeks and radiological union at 12 weeks. Five patients (6.6%) had radiological non-union of which four underwent revision surgery with plate fixation. One patient had delayed union while one had dorsal staple back-out but did not warrant removal. None required staple removal from hardware prominence. There was no significant difference in union or complication rates with regards to gender or presence inflammatory arthritis.Conclusion:This study demonstrates that the outcome of 1st MTPJ fusion with two memory staples in orthogonal position is comparable with other modalities of fixation in terms of rate of union and resurgery. It is safe, simple and easily reproducible technique. Besides, none of the patients in this series required implant removal for hardware related complications. This could be advantageous compared to fewer other modalities like plate fixation, though larger studies are needed to confirm it.