Background: Although different fixation techniques for the Akin osteotomy have been described in the literature, there are no many studies trying to analyze the differences between the types of fixation available. The aim of this study is to analyze if there are any differences between three types of staple fixation available in the market.
Method: We present a retrospective study of 145 cases in which an Akin osteotomy was performed and fixed with three different kinds of implants staple A (28%), staple B (45%), and staple C (27%). Staple A is made out of stainless steel, and the surgeon mechanically controls the compression applied. Staple B increases the compression when heat is applied to it. Staple C has an intrinsic elastic memory that closes the osteotomy. In all cases, distal articular set angle, interphalangeal joint obliquity angle, and metatarsophalangeal angle were measured pre-operatively and 1.5 months post-operatively on dorsoplantar weight-bearing radiographs. Other details such as post-operative complications, implant migration, osteolysis, or fracture of the lateral cortex during surgery were also recorded.
Results: Clinical and radiological results show no relevant differences between the three types of fixation. The mean angular corrections of DASA, interphalangeal joint obliquity angle, and metatarsophalangeal angle were 5, 12, and 21, respectively, for staple A; 4, 10, and 19, respectively, for staple B; and 7, 10, and 23, respectively, for staple C. The rates of intra-operative and post-operative complications were similar for all groups. There was one case of infection per group. We had five cases of delayed union two with staple A and three with staple C. In four cases, there was a loss of correction, two of them fixed with staple A and two with staple C. Seven cases developed a Südeck's syndrome, four of them fixed with staple A and three with staple C. Fifteen patients suffered an uncontrolled fracture of the lateral cortex of the phalanx when performing the osteotomy (3, 8, and 4 cases fixed with staples A, B, and C, respectively), and 87.5% of the patients that developed a plantar displacement of the osteotomy had an uncontrolled fracture of the lateral cortex (p < 0.05). All three staples achieved a rigid internal fixation and minimal periosteum damage and provided a good bone-bone contact.
Conclusions: According to our results, the radiological differences are minimal, and although the thermal compression staple had less complication, clinical differences were also not statistically significant. This means the choice of implant could be left to the surgeon's preferences or made according to cost.