Restpartikelfreie raue Oberflächen nach Stahldrahtkornstrahlen in der Hüftendoprothetik / Residual particle free rough surfaces after rough blasting with steel grit in total hip arthroplasty

[Cementless total hip arthroplasty: a review]

The purpose of total hip replacement (THR) is the restoration of a painless functioning hip joint with the main focus on the biomechanical properties. Advances in surgical techniques and biomaterial properties currently allow predictable surgical results in most patients. Despite the overwhelming success of this surgical procedure, the debate continues surrounding the optimal choice of implants and fixation. Femoral and acetabular implants with varying geometries and fixation methods are currently available. Problems inherent with acrylic bone cement, however, have encouraged surgeons to use alternative surfaces to allow biologic fixation. Optimal primary and secondary fixation of cementless hip stems is a precondition for long-term stability. Important criteria to achieve primary stability are good rotational and axial stability by press-fit fixation. The objective of the cementless secondary fixation is the biological integration of the implant by bony ingrowth. Nevertheless, current investigations show excellent results of cementless fixation even in older patients with reduced osseous quality. The main advantages of cementless fixation include biological integration, reduced duration of surgery, no tissue damage by cement polymerization and reduction of intraoperative embolisms. In comparison to cemented THR both, cementless sockets and stems provide good long-term results.

Impact of preoperative variables on the functional and radiological outcome of an uncemented femoral stem: a prospective two-year follow-up

The demand for improved clinical outcomes in total hip arthroplasty (THA) has led to improvements in fixation, bone ingrowth and designs providing an increased range of motion.The purpose of this prospective clinical study was to evaluate the outcome of a new cementless stem (Hipstar). The variables of body mass index (BMI), gender, preoperative function and age were explored as predictors for recovery after surgery. Clinical and radiological evaluation of 100 patients were undertaken preoperatively and at 6, 12 and 24 months postoperatively using the Harris Hip Score (HHS), WOMAC-Score and the SF-36-Score. The mean preoperative HHS was 53.6 + or - 14.5 points and it increased significantly to 82.8 + or - 15.4 at the postoperative evaluation at 24 months (WI-test p<0.001). Diminished preoperative function led to a lower postoperative score, but BMI, age and gender were not predictors of clinical and radiological outcome. Due to stress-shielding the straight Hipstar stem revealed radiolucent lines of between 41.5% and 68.5% in the proximal Gruen zones, which indicates a higher primary and secondary stability by enhanced osseous integration compared to other straight stems. Our clinical results are encouraging, but long-term follow-up will be necessary to confirm the successful introduction of the new Hipstar stem.

Cementless total hip replacement: a prospective clinical study of the early functional and radiological outcomes of three different hip stems

INTRODUCTION

Optimal fixation of cementless total hip stems is essential for long-term survival rates.

AIM

The purpose of this prospective study was to evaluate the early clinical and radiological outcomes of two new total hip stems with metaphyseal (Symax®) and predominantly diaphyseal (Hipstar®) anchoring principles in comparison to the well-established straight Zweymueller (SL-Plus®) stem.

METHOD

Clinical and radiological evaluations of 74 patients were undertaken preoperatively as well as at 6 and 12 months postoperatively using the Harris Hip Score (HHS) and Western Ontario and McMaster Universities-Score.

RESULTS

During follow-up no stem had to be revised. The mean preoperative HHS of the three study groups amounted to 54.6 ± 15.7 points. At the 12 months follow-up the mean HHS in the SL-Plus group (n = 22) was 88.3 ± 10.5 points, in the Hipstar group (n = 25) 83.3 ± 15.0 and the in Symax group (n = 27) 83.6 ± 15.1. Due to stress shielding the straight Hipstar stem revealed radiolucent lines in the proximal Gruen zones of about 60%, whereas the SL-Plus stem showed significantly more radiolucent lines (87%). However, subsequent long-term studies must be carried out in order to clarify if the progression of radiolucent lines may influence the clinical result and implant longevity.

Comparative surface examinations on corund blasted titanium implants and explants in total hip arthroplasty

INTRODUCTION

Blasting techniques using corundum to create rough surfaces are used in many different processes for the surface treatment of hip implants. Recent evidence points an association between residual particles and early loosenings in the sense of third-body wear.

MATERIALS AND METHOD

The surfaces of five unused, original-packaged CLS stems and ARR-Titan supporting rings, respectively, were compared with five explanted CLS stems and ARR-Titan supporting rings.

RESULTS

The surface of the ARR-Titan supporting rings was adhered to Al2O3 particles at 23.2+/-2.5% on the implants and 12.3+/-3.0% on the explants (P < 0.0001). For the CLS stem, the surface to which Al2O3 particles adhered was 16.4+/-2.2 % on the implants, whereas the surface to which Al2O3 particles adhered was 12.4+/-3.3% on the explants (P = 0.0275).

DISCUSSION

The results of this study show that corundum particles can be found to cover a high percentage on rough-blasted titanium surfaces of ready-to-use devices. In contrast, this contamination is significantly less on the explants treated in an identical fashion prior to implantation.