This study investigates head-neck taper corrosion with varying head size in a novel hip simulator instrumented to measure corrosion related electrical activity under torsional loads. In all, six 28 mm and six 36 mm titanium stem-cobalt chrome head pairs with polyethylene sockets were tested in a novel instrumented hip simulator. Samples were tested using simulated gait data with incremental increasing loads to determine corrosion onset load and electrochemical activity. Half of each head size group were then cycled with simulated gait and the other half with gait compression only. Damage was measured by area and maximum linear wear depth.Aims
Methods
Vitamin E-infused highly crosslinked polyethylene (VEPE) has been introduced into total hip arthroplasty (THA) with the aim of further improving the wear characteristics of moderately and highly crosslinked polyethylenes (ModXLPE and HXLPE). There are few studies analyzing the outcomes of vitamin E-infused components in cemented arthroplasty, though early acetabular component migration has been reported. The aim of this study was to measure five-year polyethylene wear and acetabular component stability of a cemented VEPE acetabular component compared with a ModXLPE cemented acetabular component. In a prospective randomized controlled trial (RCT), we assessed polyethylene wear and acetabular component stability (primary outcome) with radiostereometric analysis (RSA) in 68 patients with reverse hybrid THA at five years follow-up. Patients were randomized to either a VEPE or a ModXLPE cemented acetabular component.Aims
Methods
To investigate the longevity of uncemented fixation of a femoral
component in total hip arthroplasty (THA) in patients with Dorr
type C proximal femoral morphology. A total of 350 consecutive uncemented THA in 320 patients were
performed between 1983 and 1987, by a single surgeon using the Taperloc
femoral component. The 63 patients (68 hips) with Dorr type C proximal
femoral morphology were the focus of this review. The mean age of
the patients was 69 years (24 to 88) and mean follow-up was 16.6
years (ten to 29). Survival analysis included eight patients (eight
hips) who died without undergoing revision surgery prior to obtaining
ten years follow-up. All 55 surviving patients (60 hips) were available
for clinical assessment and radiographic review. As a comparator
group, the survival and implant fixation in the remaining 282 THAs
(257 patients) with Dorr type A and B morphology were evaluated.
The mean age of these patients was 52 years (20 to 82).Aims
Patients and Methods
Large femoral heads have been used with increasing
frequency over the last decade. The prime reason is likely the effect
of large heads on stability. The larger head neck ratio, combined
with the increased jump distance of larger heads result in a greater
arc of impingement free motion, and greater resistance to dislocation
in a provocative position. Multiple studies have demonstrated clear
clinical efficacy in diminishing dislocation rates with the use
of large femoral heads. With crosslinked polyethylene, wear has
been shown to be equivalent between larger and smaller heads. However,
the stability advantages of increasing diameter beyond 38 mm have
not been clearly demonstrated. More importantly, recent data implicates
large heads in the increasing prevalence of groin pain and psoas impingement.
There are clear benefits with larger femoral head diameters, but
the advantages of diameters beyond 38 mm have not yet been demonstrated
clinically.
