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

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 < .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.

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

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 < .001), middle zone (P < .001), and in the combined score (P < .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.

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.

Association of surgeon factors with outcome scores after total knee arthroplasty.

PURPOSE: To identify preoperative factors (including surgeon factors) associated with outcome scores after total knee arthroplasty (TKA). METHODS: Medical records of 2848 patients (3458 knees) who underwent primary TKA by 27 orthopaedic specialists were retrieved. Three specialty knee surgeons who had one-year fellowship in TKA performed 1930 TKAs, and 24 general orthopaedic surgeons performed 1528 TKAs. Four of them (including all 3 specialty knee surgeons) were ultrahigh- volume (≥ 100 TKAs a year), and 21 of them were senior consultants (≥ 5 years post residency). At 2 years, 2922 (85%) of knees had complete followup data. Oxford Knee Score, Knee Society knee and function scores, and SF-36 quality-of-life score were assessed by independent physiotherapists before and after surgery. Outcomes were compared in terms of dichotomised specialty, seniority, and surgical volume of surgeons. RESULTS: Comparing ultra-high-volume (≥ 100 TKAs per year) specialty knee surgeons with general orthopaedic surgeons, the former achieved better outcomes in terms of the Oxford Knee Score at 6 months, Knee Society knee and function scores at 2 years, and SF-36 scores at 6 months and 2 years. Comparing lower-volume (<100 TKAs per year) specialty knee surgeons with general orthopaedic surgeons, the former still achieved better outcome and quality-of-life scores, except for SF-36 Mental Component Score at 2 years. CONCLUSION: Specialty training and clinical research in TKA improved outcome and quality-of-life scores.