Effect of Taper Design on Trunnionosis in Metal on Polyethylene Total Hip Arthroplasty.

This study examines how taper design affects corrosion and fretting at the head trunnion surface. All hip prostheses retrieved between 1999 and 2013 with 28mm/+0 heads were selected, resulting in 44 cobalt-chrome-on-polyethylene implants, representing six taper designs. Mean implantation time: 8.9±3.7years. The femoral head tapers were scored for fretting and corrosion using the Goldberg scale as both a combined score and by three zones (apex, central and base). There was no difference in age (P=0.34), BMI (P=0.29), or implantation time (P=0.19) between taper groups. The 11/13 taper had the highest combined corrosion and fretting score, but no difference (P=0.22) between groups for combined scores (P=0.22 for corrosion, P=0.19 for fretting). In a zone-specific analysis, the 11/13 taper had highest corrosion score at base zone (P=0.02). Taper design had a significant effect on corrosion at base of trunnion

Trunnionosis: Does Head Size Affect Fretting and Corrosion in Total Hip Arthroplasty?

© 2016 Elsevier Inc. Background Wear and tribocorrosion at the modular head–neck taper interface may be a cause of failure in metal-on-polyethylene total hip arthroplasty (THA). The present investigation endeavored to elucidate the effect of femoral head diameter on fretting and corrosion in retrieved head–neck tapers. Methods A retrieval analysis of THA prostheses in vivo for a minimum of 1 year was performed. Twenty-three femoral heads of 32-mm diameter were matched with 28-mm heads based on time in vivo and head length (−3 mm to +8 mm). All included implants featured a single taper design from a single manufacturer. Fretting and corrosion damage scoring was performed for each implant under stereomicroscopic visualization. Results Head diameter was observed to affect fretting (P =.01), with 32-mm femoral heads exhibiting greater total fretting scores than 28-mm heads. Fretting damage was greatest (P =.01) in the central concentric zone of the femoral head bore tapers, regardless of head diameter, length, or stem offset. No significant effect on total corrosion scores was observed for any head or stem variable. Retrieved implant total corrosion scores were positively correlated (ρ = 0.51, P \u3c.001) with implantation time. Conclusion Increased femoral head diameter in THA may produce greater fretting damage owing to and increased head–neck moment arm. There is no associated increase in corrosion with 28-mm and 32-mm heads of this taper design. The longer a THA prosthesis is implanted, the greater the risk of damage due to corrosion

Does the Additional Articulation in Retrieved Bipolar Hemiarthroplasty Implants Decrease Trunnionosis Compared to Total Hip Arthroplasty?

© 2017 Background Trunnionosis at the modular head-neck taper interface in metal-on-polyethylene total hip arthroplasty (MoP THA) has been shown to occur, and represents a potential mode of MoP THA failure. The purpose of the present investigation is to elucidate differences in fretting and corrosion at the head-neck taper interface of prostheses retrieved from bipolar hemiarthroplasty (BH) and MoP THA. Methods A retrieval analysis of BH and MoP THA prostheses featuring a single taper design from a single manufacturer and in vivo for a minimum 2 years was performed. Fifteen femoral heads of 28-mm diameter and corresponding femoral stems retrieved from BH were compared with MoP THA implants matched based on time in vivo and head length (28 mm, −3 mm to 28 mm, +8 mm). Fretting and corrosion damage scoring was completed under stereomicroscopic visualization. Results Femoral head bore tapers retrieved from BH exhibited decreased overall fretting (P =.02), when compared to those retrieved from MoP THA. Total corrosion scores for all retrieved implants were positively correlated with implantation time (ρ = 0.54, P \u3c.02). Conclusion Femoral heads retrieved from BH exhibit decreased fretting damage compared to those retrieved from MoP THA. The added articulation in BH implants may decrease torque produced at the head-neck taper junction, thereby decreasing fretting. Increased fretting damage in implants from MoP THA is not associated with increased corrosion in 28-mm heads of this taper design. The longer a BH or MoP THA prosthesis is implanted, the greater the risk of damage due to corrosion

Biomechanical Consequences of Nail Insertion Point and Anterior Cortical Perforation for Antegrade Femoral Nailing

This biomechanical study assessed the influence of changing antegrade cephalomedullary nail insertion point from anterior to neutral to posterior locations relative to the tip of the greater trochanter with or without anterior cortical perforation in the distal femur. Artificial osteoporotic femurs and cephalomedullary nails were used to create 5 test groups each with 8 specimens: intact femur without a nail or perforation, anterior nail insertion point without perforation, neutral nail insertion point without perforation, posterior nail insertion point without perforation, and posterior nail insertion point with perforation. Nondestructive biomechanical tests were done at 250 N in axial, coronal 3-point bending, sagittal 3-point bending, and torsional loading in order to measure overall stiffness and bone stress. The intact femur group vs. all femur/nail groups had lower stiffness in all loading modes (p≤0.018), as well as higher bone stress in the proximal femur (p≤0.027) but not in the distal femur above the perforation (p=0.096). Compared to each other, femur/nail groups only showed differences in sagittal 3-point bending stiffness for anterior and neutral vs. posterior nail insertion points without (p≤0.025) and with perforation (p≤0.047). Although it did not achieve statistical significance (p≥0.096), moving the nail insertion point from anterior to neutral to posterior to posterior with perforation did gradually increase bone stress by 45% (proximal femur) and 46% (distal femur). No femur or hardware failures occurred. Moving the nail insertion point and the presence of a perforation had little effect on stiffness, but the increased bone stress may be important as a predictor of fracture. Based on current bone stress results, surgeons should use anterior or neutral nail insertion points to reduce the risk of anterior cortical perforation

Tribocorrosion: Ceramic and Oxidized Zirconium vs Cobalt-Chromium Heads in Total Hip Arthroplasty

© 2016 Elsevier Inc. Background This matched-cohort study aims to compare tribocorrosion between matched ceramic and cobalt-chromium femoral head trunnions and between matched Oxinium and cobalt-chromium femoral head trunnions. Secondary objectives were to investigate whether taper design, depth of trunnion, implantation time, age, body mass index, and gender have an effect on fretting and corrosion. Methods All hip prostheses retrieved between 1999 and 2015 at one center were reviewed, giving a total of 52 ceramic heads. These were matched to a cobalt-chromium cohort according to taper design, head size, neck length, and implantation time. The trunnions were examined by 2 observers using a 4-point scoring technique and scored in 3 zones: apex, middle, and base. The observers were blinded to clinical and manufacturing data where possible. A separate matched-cohort analysis was performed between 8 Oxinium heads and 8 cobalt-chromium heads, which were similarly scored. Results Ceramic head trunnions demonstrated a lower median fretting and corrosion score at the base zone (P \u3c.001), middle zone (P \u3c.001), and in the combined score (P \u3c.001). Taper design had a significant effect on fretting and corrosion in the apex zone (P =.04) of the ceramic group, as well as the cobalt-chromium group (P =.03). Between Oxinium heads and cobalt-chromium heads, there was no significant difference in the fretting and corrosion score across all 3 zones (base: P =.22; middle: P =.92; and apex: P =.71) and for the combined score (P =.67). Conclusion This study shows that ceramic head confers an advantage in trunnion fretting and corrosion. Taper design and implantation time were also significant factors for fretting and corrosion

Factors Predictive of Early Complications Following Total Ankle Arthroplasty

Background: The safety of outpatient total ankle arthroplasty (TAA), and factors predictive of early complications are poorly understood. The objective of this study was to determine the frequency of early complications in patients undergoing outpatient TAA compared to a matched inpatient TAA cohort. Factors predictive of early complications following TAA are elucidated. Methods: A retrospective review of prospectively collected data from the 2011-2018 American College of Surgeons–National Surgical Quality Improvement Program (ACS-NSQIP) database was performed. An unadjusted analysis comparing complication rates in outpatient, and inpatient TAA was performed followed by a propensity score–matched cohort analysis. A multivariate logistic regression model was then used to identify significant independent predictors for complications, reoperation, and readmission following TAA. Results: A total of 1487 patients (198 outpatient, 1289 inpatient) undergoing TAA were included in the study. Inpatient TAA was associated with increased 30-day readmission compared with outpatient TAA (3.54% vs 0.51%, P = .032) in a matched cohort analysis. Thirty-eight (2.6%) patients had a minor complication, with 16 (1.1%) patients having a major complication after TAR. Nineteen (1.3%) patients underwent reoperation, and 42 (2.8%) patients were readmitted within 30 days of the index TAR. Multivariate analysis identified factors predictive of early complications to include length of stay (LOS) >2 days, smoking, hypertension, bleeding disorders, and diabetes mellitus. Conclusion: From this relatively limited data set, outpatient TAA appears to be safe for management of end-stage ankle arthritis in select patients. Inpatient status was associated with an increased rate of 30-day readmission following TAA. Postoperative length of stay >2 days, smoking, hypertension, bleeding disorders, and diabetes mellitus were identified to be associated with early postoperative complications following TAA in this cohort. Level of Evidence Level III, retrospective cohort study