Biomechanical effect of metal augment and bone graft on cup stability for acetabular reconstruction of total hip arthroplasty in hip dysplasia: a finite element analysis

Abstract

Background Different methods of acetabular reconstruction with total hip arthroplasty (THA) for Crowe II and III of adult developmental dysplasia of the hip (DDH) acetabular bone defect have been implemented clinically. However, the biomechanical effect of different augmented materials for acetabular reconstruction in THA on shell stability has never been discussed. Methods In the present study, autologous bone graft (BG)and metal (Ti6Al4V) augment (MA) were simulated with several acetabular bone defect models of DDH in THA. The contact pressure and micromotion between the shell and host bone were measured for evaluating the shell stability using a finite element method. Results The peak contact stress between shell and host bone was higher in the MA situation (12.45 vs 8.71 MPa). And the load transfer path was different, for BG models, the high local contact stresses were found at the junction of bone graft and host bone while for MA models the concentrated contact stresses were at the surface of MA. The peak relative micromotion between shell and host bone was higher in the MA situation (12.61 vs 11.13 µm). However, the peak micromotion decreased in the contact interface of MA and cup compared to the BG models. Conclusions The higher micromotion was found in MA models, however, enough for bone ingrowth, and direct stronger fixation was achieved in the MA-cup interface. Thus, we recommended the MA can be used as an option, even for Crowe III, however, the decision should be made from clinical follow-up results.

Biomechanical analysis and clinical observation of 3D-printed acetabular prosthesis for the acetabular reconstruction of total hip arthroplasty in Crowe III hip dysplasia

“…The FE model used in this study for MAP acetabular reconstruction under walking and jogging loads had been validated through comparison with previous biomechanical models. The results of implant peak stress from Fu et al (2018) (50.25 MPa for walking and 75.86 MPa for jogging) and relative micromotion under walking load (12.61 μm) from Wang et al (2022) were compared with those of our study: implant peak stress of 52.3 MPa (walking) and 83.1 MPa (jogging), along with a relative micromotion of 13.7 μm under walking load. The results are similar, verifying that our FE model is suitable for further analysis.…”

“…Since the femoral part was not involved in this study, to save the calculation time of the Finite element (FE) model, the construction of the femoral and femoral stem prosthesis was omitted in this paper. In addition, to facilitate the application of the load, the femoral head of the prosthesis was simplified to a hemisphere in FE analysis ( Wang et al, 2022 ). Finally, the aforementioned model was non-fluid-assembled in 3-Matic ( Figures 1D, E ).…”

Total hip arthroplasty with porous tantalum trabecular metal pads in patients with Crowe IV developmental dysplasia of the hip: a midterm followup study

“…Many different strategies have been used to reconstruct the acetabulum. These include autogenous femoral head transplantation, impacted bone grafting, and the use of metal cups with particle bone grafting [ 17 ]. Our previous study used porous-coat acetabular components and transverse subtrochanteric osteotomy to manage patients with Crowe type IV DDH.…”

“…Various methods and techniques have been proposed to restore the normal anatomical relations of the distorted hip joint in Crowe IV DDH. Additionally, previous studies have described several strategies to reconstruct the abnormal acetabulum using autogenous femoral head grafts, embedded bone grafts, and porous tantalum cups plus granular bone grafts during THA [ 16 , 17 ]. However, the optimal treatment remains unclear.…”

Extra‐articular Blocking Technique to Resolve Severe Acetabular Bone Defect in Developmental Dysplasia of the Hip

“…This procedure forms a blocking effect to offload the shearing force directing the cup toward the proximal and medial migration. The exposed part of the screws should not be more than one‐third of their length as shown by an initial finite element analysis 11,12 . When the total hip components were reduced, the morselized cancellous bony fragments derived from acetabular reaming were collected and used to fill the irregular bone defect, and the tails of the screws were covered in most situations (Fig.…”