Modular dual mobility (DM) prostheses in which a cobalt-chromium liner is inserted into a titanium acetabular shell ( This was a prospective study of patients between 18 and 65 years of age, with a body mass index (BMI) < 35 kg/m2 and University of California at Los Angeles (UCLA) activity score > 6, who received a modular cobalt-chromium acetabular liner, highly crosslinked polyethylene mobile bearing, and cementless titanium femoral stem for their primary THA. Patients with a history of renal disease and metal hardware elsewhere in the body were excluded. A total of 43 patients (30 male, 13 female; mean age 52.6 years (Aims
Patients and Methods
Despite well-fixed implants, persistent pain following total hip arthroplasty (THA) remains a concern. Various surgical approaches have been advocated, yet whether patient-reported pain differs amongst techniques has not been investigated. This study's purposes were to determine differences in patient-reported pain based on surgical approach (direct anterior –DA versus posterolateral-PL) or PL approach incision length. Our hypothesis was that no differences in patient-reported pain would be present. A retrospective, IRB-approved investigation from 2 centers was performed. 7 fellowship trained arthroplasty surgeons (3 DA, 3 PL, 1 both) enrolled patients undergoing primary THA for non-inflammatory arthritis. PL approach patients were categorized based on incision length (6–8cm, 8–12cm, 12–15cm). Exclusion criteria were a prior hip surgery, revision procedure, or limited postoperative mobility. All THAs were performed using a cementless titanium, proximally coated, tapered femoral stem and hemispherical acetabular component. All patients had a minimum of 1-year clinical follow-up with radiographically well-fixed components. A pain-drawing questionnaire was administered in which patients identify the location and intensity of pain on an anatomic diagram. Independent Student's t-tests and Chi-square analyses were performed (p<0.05 = significant). Power analysis indicated 800 patients in each cohort would provide adequate power to detect a 4% difference in patient-reported pain (alpha = 0.05, beta = 0.80).Introduction
Methods
To assess clinical outcomes, metal ion levels, and periprosthetic femoral bone mineral density (BMD) in young, active patients receiving a modular dual mobility acetabulum and recently introduced titanium, proximally coated, tapered femoral stem design. This was a prospective study of patients 65 years of age, with a BMI 35 kg/m2, and UCLA activity score > 6 who received a modular cobalt chrome acetabular liner, highly cross-linked polyethylene mobile bearing, and cementless titanium femoral stem for their primary THA. Patients with a history of renal disease and metal hardware elsewhere in the body were excluded. All patients had a minimum of 2-year clinical follow-up. Patient reported outcome measures, whole blood metal ion levels ( 43 patients (30 male, 13 female; mean age 52.6 ± 6.5 years) were enrolled. Harris Hip Scores improved from 54.1 ± 20.5 to 91.2 ± 10.8 at 2 years postoperatively (p<0.001). All patients had radiographically well-fixed components, no patients have sustained an instability event, and no patients have required a return to the operating room or revision procedure. Mean cobalt levels increased from 0.065 ± 0.03 The mean femoral BMD ratio was maintained in Gruen zones 2 thru 7 at both 1- and 2-years postoperatively using this stem design (Table 2). At 2 years postoperatively, BMD in the medial calcar was 101.5% of the baseline value. Use of a modular dual mobility prosthesis and cementless, tapered femoral stem has shown encouraging results in young, active patients undergoing primary THA. Elevation in mean cobalt levels and the presence of four patients outside the reference range at 2 years postoperatively demonstrates the necessity of continued surveillance in this cohort. For any figures or tables, please contact authors directly:
