Сomparative analysis of large diameter bearing ceramic monoblock acetabular components.

INTRODUCTION

The goal of total hip arthroplasty (THA) is to provide ease to patients with persistent and exhausting pain. Durability is the main challenge associated with any tribological pair, with the aim of minimizing wear and thus avoiding problems with aseptic loosening of components and osteolysis. When polyethylene inserts are used in young patients, we should always consider their disadvantages, e.g., increased wear of the interacting components. Proper selection of friction pairs allows prolonged implant life. Ceramic-on-ceramic (CoC) friction pairs should provide long-term wear of the friction components.

OBJECTIVES

To evaluate the mid-term results of using the monoblock Maxera Cup (Zimmer Biomet) acetabular system in cementless THA.

METHODS

We operated on 151 patients using the monoblock Maxera Cup (Zimmer Biomet) acetabular system. The mean follow-up duration was 6 years (73.8 ± 11.7 months). Fifty-seven women and 94 men aged 19-64 years were surgically treated. All 170 THA cases in 151 patients were divided into 3 groups according to the diameters of the CoC friction pairs used (40, 44, and 48 mm). As a control group, we have taken 50 patients who received 50 THA using a standard 36 mm CoC friction pair. The achieved functional results were evaluated using the HHS scale, WOMAC scale, and SF36 scale. We also evaluated the mean duration of surgical intervention and blood loss.

RESULTS

When assessing long-term results, the average HHS significantly increased from 34.10 (before surgery) to 87.50 (postoperation) points in the 1st group, from 46.24 to 96.5 points in the 2nd group, and from 38.70 to 92.10 points in the 3rd group. From preoperative examination to 1 year after surgery, there was a 2.4-fold improvement in the functional results in group 1 and 1,8 and 2.9 -fold improvement in groups 2 and 3, indicating excellent treatment results. Inconsistent creaking in the implanted joint was noted in only 2.6% of cases in which a CoC friction pair with a diameter of 44 mm was used. We did not observe any complications associated with aseptic or septic loosening of the components either clinically or radiologically during the 7-year follow-up period after surgery in the entire patient population.

CONCLUSIONS

1Use of the CoC monoblock allowed us to expect an increase in the life cycle of the implant and provided good joint function and perception by the patient.2Monoblock cups provided good joint function and perception by the patient.3Acoustic effects, in the form of minor creaking, did not affect the functional results.