Few studies have examined the order in which
a spinal osteotomy and
Aims. Fretting and corrosion at the modular head/neck junction, known
as trunnionosis, in
We conducted a longitudinal study including patients with the same type of primary hybrid
Dislocation is a common and well-studied complication after
The recommendation that patients having a
Objectives. Modular junctions are ubiquitous in contemporary hip arthroplasty. The head-trunnion junction is implicated in the failure of large diameter metal-on-metal (MoM) hips which are the currently the topic of one the largest legal actions in the history of orthopaedics (estimated costs are stated to exceed $4 billion). Several factors are known to influence the strength of these press-fit modular connections. However, the influence of different head sizes has not previously been investigated. The aim of the study was to establish whether the choice of head size influences the initial strength of the trunnion-head connection. Materials and Methods. Ti-6Al-4V trunnions (n = 60) and two different sizes of cobalt-chromium (Co-Cr) heads (28 mm and 36 mm; 30 of each size) were used in the study. Three different levels of assembly force were considered: 4 kN; 5 kN; and 6 kN (n = 10 each). The strength of the press-fit connection was subsequently evaluated by measuring the pull-off force required to break the connection. The statistical differences in pull-off force were examined using a Kruskal–Wallis test and two-sample Mann–Whitney U test. Finite element and analytical models were developed to understand the reasons for the experimentally observed differences. Results. 36 mm diameter heads had significantly lower pull-off forces than 28 mm heads when impacted at 4 kN and 5 kN (p < 0.001; p < 0.001), but not at 6 kN (p = 0.21). Mean pull-off forces at 4 kN and 5 kN impaction forces were approximately 20% larger for 28 mm heads compared with 36 mm heads. Finite element and analytical models demonstrate that the differences in pull-off strength can be explained by differences in structural rigidity and the resulting interface pressures. Conclusion. This is the first study to show that 36 mm Co-Cr heads have up to 20% lower pull-off connection strength compared with 28 mm heads for equivalent assembly forces. This effect is likely to play a role in the high failure rates of large diameter MoM hips. Cite this article: A. R. MacLeod, N. P. T. Sullivan, M. R. Whitehouse, H. S. Gill. Large-diameter
There remains confusion in the literature with regard to the spinopelvic relationship, and its contribution to ideal acetabular component position. Critical assessment of the literature has been limited by use of conflicting terminology and definitions of new concepts that further confuse the topic. In 2017, the concept of a Hip-Spine Workgroup was created with the first meeting held at the American Academy of Orthopedic Surgeons Annual Meeting in 2018. The goal of this workgroup was to first help standardize terminology across the literature so that as a topic, multiple groups could produce literature that is immediately understandable and applicable. This consensus review from the Hip-Spine Workgroup aims to simplify the spinopelvic relationship, offer hip surgeons a concise summary of available literature, and select common terminology approved by both hip surgeons and spine surgeons for future research. Cite this article:
Studies describing the effect of body mass index (BMI) on the outcome of
Hip disease occurs in between 8% and 28% of patients with Down’s syndrome, many of whom develop disabling pain. We have carried out
Ultra-high-molecular-weight polyethylene sterilised in the absence of air and highly cross-linked polyethylene have been used to avoid osteolysis and loosening in
Despite advances in contemporary hip and knee
arthroplasty, blood loss continues to be an issue. Though blood transfusion
has long been used to treat post-operative anemia, the associated
risks are well established. The objective of this article is to
present two practical and effective approaches to minimising blood
loss and transfusion rates in hip and knee arthroplasty: the use
of antifibrinolytic medications such as tranexamic acid and the
adoption of more conservative transfusion indications.
This study compared the demographic, clinical and patient-reported outcomes after
We reviewed the literature on the currently available
choices of bearing surface in
Systemic mastocytosis is a rare condition that often involves the bone marrow. We report the case of a patient with systemic mastocytosis who underwent
We performed a randomised, radiostereometric study comparing two different bone cements, one of which has been sparsely clinically documented. Randomisation of 60
We studied the rate of revision in 84 consecutive
We have reviewed a group of patients with iliopsoas impingement after
Metal artefact reduction (MAR) MRI is now widely
considered to be the standard for imaging metal-on-metal (MoM) hip
implants. The Medicines and Healthcare Products Regulatory Agency
(MHRA) has recommended cross-sectional imaging for all patients
with symptomatic MoM bearings. This paper describes the natural
history of MoM disease in a 28 mm MoM
We have evaluated the extent to which diabetes affects the revision rate following