Radiostereometric analysis of keeled versus pegged glenoid components in total shoulder arthroplasty: a randomized feasibility study.

Background: This study aimed to assess differences in the fixation and functional outcomes between pegged and keeled all-polyethylene glenoid components for standard total shoulder arthroplasty.

Methods: Patients were randomized to receive a keeled or pegged all-polyethylene glenoid component. We used model-based radiostereometric analysis (RSA) to assess glenoid fixation and subjective outcome measures to assess patient function.

Wear of a sequentially annealed polyethylene acetabular liner.

Background And Purpose: We previously reported on a randomized controlled trial (RCT) that examined the effect of adding tobramycin to bone cement after femoral stem migration. The present study examined femoral head penetration into both conventional and highly crosslinked polyethylene acetabular liners in the same group of RCT patients, with a minimum of 5 years of postoperative follow-up.

Patients And Methods: Linear penetration of the femoral head into an X3 (Stryker) crosslinked polyethylene (XLPE) liner was measured in 18 patients (19 hips) using radiostereometric analysis (RSA).

Prediction of backside micromotion in total knee replacements by finite element simulation.

The micromotion at the interface between the polyethylene tibial insert and metal tibial tray [corrected] in modular total knee replacements [corrected] has been shown to contribute to wear particle-induced osteolysis and may [corrected] cause implant failure. Therefore, studying the design parameters that are involved in the backside wear process is an important task that may lead to improvement in new total knee replacements. In the present study, a finite element model was developed to predict the backside micromotion along the entire modular interface.

The effect of adding tobramycin to Simplex P cement on femoral stem micromotion as measured by radiostereometric analysis: a 2-year randomized controlled trial.

Background: Previous in vitro research on addition of antibiotics to bone cement has found no statistically significant deterioration in mechanical properties. However, no clinical studies have compared the performance of tobramycin-laden bone cement with that of standard bone cement (Simplex P).

Patients And Methods: 23 patients (25 hips) were randomized to receive an Exeter (Stryker Orthopaedics) femoral stem cemented with either Simplex P (standard) or Simplex T (tobramycin-laden) cement.

The Frank Stinchfield Award: Dislocation in revision THA: do large heads (36 and 40 mm) result in reduced dislocation rates in a randomized clinical trial?

Background: Dislocation after revision THA is a common complication. Large heads have the potential to decrease dislocation rate, but it is unclear whether they do so in revision THA.

Questions/purposes: We therefore determined whether a large femoral head (36 and 40 mm) resulted in a decreased dislocation rate compared to a standard head (32 mm).

Posterior condyle surface damage on retrieved femoral knee components.

Twenty-two retrieved femoral knee components were identified with posterior condyle surface damage on average at 99° flexion (range, 43°-135° flexion). Titanium alloy material transfer and abrasive surface damage were evident on cobalt-chromium alloy femoral components that were in contact with titanium alloy tibial trays. Surface damage on the retrieved Oxinium femoral components (Smith and Nephew, Inc, Memphis, Tenn) that were in contact with titanium alloy tibial trays showed gouging, associated with the removal and cracking of the oxide and exposure of the zirconium-niobium alloy substrate.