Classifications of Acetabular Defects: Do They Provide an Objective Evidence for Complexity of Revision Hip Joint Arthroplasty? (Critical Literature Review and Own Cases)

Does the interface between individual 3D acetabular implants and host bone influence the functional outcomes in patients with severe bone loss after revision surgery?

INTRODUCTION

There is a wide range of commercially produced revision implants for adequate reconstruction of acetabular large bone defects today, however, it is not always possible to achieve long-term survival of these implants. There is an increasing number of scientific publications concerning the use of custom-designed 3D components, which make it possible not only to achieve stable fixation and connect the pelvic bones but also to restore hip joint biomechanics.

OBJECTIVES

To evaluate the positioning of 3D acetabular implants after revision hip arthroplasty and its impact on clinical and functional outcomes.

METHODS

we analyzed results in 48 patients with bone defect types IIIA and IIIB Paprosky types, after revision hip arthroplasty. A prospective study was conducted from 2017 to 2023. Revision arthroplasty due to aseptic loosening of the components was performed in 30 cases and as a second stage of periprosthetic infection treatment in 18 cases.

RESULTS

We did not achieve a statistically significant difference when using additional flanges and clinical and functional results. In 2 cases we faced aseptic loosening in patients using flanges. In no case were we able to install an implant with 100% adherence to porous structure compared to preoperatively planned adherence. According to the WOMAC and VAS scales, increasing the contact area of the components showed a slight statistical difference in the improvement of clinical and functional results and the reduction of pain.

CONCLUSIONS

When acetabular 3D components adhered to the bone by more than 68%, we did not register a single complication in the postoperative period, and acetabular 3D components adhered to the bone by less than 68%, a total of 8 (16.6%) complications were registered.

Early outcomes of using custom-made augments in revision total hip arthroplasty

INTRODUCTION

The continuing high demand for revision total hip arthroplasty (RTHA) requires not only additional economic costs, but also the search for new, effective methods to manage the reconstruction of acetabular bone loss. This study focuses on the assessment of the clinical and radiographic outcomes after RTHA using custom-made augments (CMA) in the short-term follow-up period.

MATERIALS AND METHODS

We retrospectively analyzed the results of using CMAs in 19 patients (20 hips). The average follow-up period was 41.3 months. All surgery was performed on defect types III and IV as per the Gross and Saleh classification.

RESULTS

There was a statistically significant difference when comparing the Oxford Hip Score before RTHA of 15.0 (Std. deviation-5.9) and after RTHA of 36.3 (Std. deviation-6.3) (p = 0.01). All implants were radiologically stable. CMA has demonstrated a good ability to restore position of hip centre of rotation (HCOR). In the postoperative period, two patients (2 hips) had dislocations. Only one of two patients underwent re-revision due to dislocation.

CONCLUSION

Treatment of uncontained loss of bone stock in RTHA using CMA shows promising clinical and radiographic results at short-term follow-up period; however, dislocation rate is 10% in this study.

Standard Versus Custom-Made Acetabular Implants in Revision Total Hip Arthroplasty

BACKGROUND

Today, various options are used for the reconstruction of acetabular bone loss in revision total hip arthroplasty (RTHA). The aim of the study was to compare the outcomes of using standard acetabular implants (SAIs) and custom-made acetabular implants (CMAIs) in RTHA in cases with extensive acetabular bone loss.

METHODS

This was a comparative analysis of the results of 106 operations of RTHA performed during the period from January 2013 to December 2019. In 61 cases (57.5%), CMAIs were used. In 45 cases (42.5%), SAIs were implanted.

RESULTS

The incidence of aseptic loosening of the acetabular component after RTHA in uncontained loss of bone stock of the acetabulum (type III-IV as per the Gross and Saleh classification) using the CMAI was less than that using the SAI (2.4% and 10.0%, respectively). The most significant differences in aseptic loosening rates were noted after implantation of the CMAI and SAI in pelvic discontinuity with uncontained bone defect (0% and 60.0%, respectively; P<.001).

CONCLUSION

The ideal indications for the use of the CMAI are uncontained defects and pelvic discontinuity with uncontained loss of bone stock (types III-V Gross and Saleh classification). Treatment of these defects with the SAI leads to a higher incidence of aseptic loosening requiring re-revisions. Further observation is required to assess the effectiveness of using the CMAI and SAI in the long-term follow-up period.