Comparison of two reinforcement rings for primary total hip arthroplasty addressing displaced acetabular fractures: a biomechanical analysis

Abstract

Introduction Aim of this study was to biomechanically compare two different acetabular cup fixation constructs in terms of fracture fixation for displaced acetabular fractures involving the anterior column with hemitransverse fracture under partial and full weight-bearing conditions. Methods Two different reinforcement rings designed as cages for primary THA were biomechanically tested in terms of managing a complex acetabular fracture. Single-leg stance cyclic loading was performed to assess fracture gap movement and fragment rotation. Twelve hemi pelvis Sawbones were divided into two groups: primary THA with acetabulum roof reinforcement plate (ARRP) (n = 6) and primary THA with Burch-Schneider reinforcement cage (BSRC) (n = 6). Results During loading under partial weight-bearing (250 N) fracture gap movement tended to be larger in the BSRC group as compared to the ARRP group. Under full weight-bearing conditions, the ARRP showed 60% significantly less motion (p = 0.035) of the os ilium to os ischii gap compared to BSRC. Fracture gap movements between the os ilium and spina iliaca fragments were significantly reduced by 76% (p = 0.048) for ARRP in contrast to BSRC. The ARRP group also demonstrated significantly less movement in the fracture gaps os ischii to quadrilateral plate (62% reduction, p = 0.009) and quadrilateral plate to spina iliaca (87% reduction, p < 0.001). Significantly less rotational movement of the quadrilateral plate to the os ilium was exhibited by the ARRP group (p = 0.015). Conclusions The presented acetabulum roof-reinforcement plate (ARRP) provides stable conditions at the acetabular component with adequate stabilization of a displaced acetabular fracture.Publisher's Note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Primary stability of multi-hole cups compared to plate osteosynthesis in osteoporotic anterior column and posterior hemi-transverse acetabular fractures—A biomechanical comparison

“…There is only one study known to us that used a similar experimental setup and investigated the primary stability of arthroplasty of acetabular fractures with revision cups alone. However, in contrast to our study, no failure test was performed [ 11 ]. Compared to the previous studies, our test setup allows both test variants, a failure test and a cyclic loading test with the anatomically correct force direction while walking.…”

“…In contrast to the present study it must be emphasized that not all studies used an experimental set-up with an anatomical force vector in the sense of a single-legged stand [ 11 , 24 , 25 ]. Furthermore, most authors have not tested a full weight bearing or defined it very diversely, which makes it impossible to compare the results [ 25 – 27 ].…”

“…Therefore, the primary arthroplasty of acetabular fractures in elderly is increasingly discussed to avoid unnecessary secondary interventions [ 6 , 9 , 11 , 12 ].…”

The acetabular roof reinforcement plate for the treatment of displaced acetabular fractures in the elderly: results in 59 patients

“…The key part of the presented procedure is an antiprotrusion ring called ARRP (41medical, Bettlach Switzerland). The ARRP is characterized by a high primary stability allowing for early FWB in almost all cases [ 42 ]. The high primary stability is provided by a high number of 3.5-mm angular stable screws fixed in stable iliac bone (2–4 upper ring screws and 8 screws through the fin).…”

“…According to Culemann et al [ 43 ] we used an anterior column with posterior hemitransverse fracture model. In this study, the high primary stability of the ARRP was demonstrated and was significantly higher than that of the Burch Schneider ring [ 42 ].…”