The eccentric glenosphere was principally introduced into reverse
shoulder arthroplasty to reduce the incidence of scapular notching.
There is only limited information about the influence of its design
on deltoid power and joint reaction forces. The aim of our study was to investigate how the diameter and
eccentricity of the glenosphere affect the biomechanics of the deltoid
and the resultant joint reaction forces. Different sizes of glenosphere and eccentricity were serially
tested in ten cadaveric shoulders using a custom shoulder movement
simulator.Aims
Methods
Until now, there has been no consensus as to whether stemmed
acetabular components are appropriate for use in patients undergoing
revision total hip arthroplasty (THA) who have major acetabular
defects or pelvic discontinuity. We wished to address this deficiency
in the literature. We carried out a retrospective study of 35 patients (six men
and 29 women) with a mean age of 68 years (37 to 87), with major
acetabular defects who underwent revision THA between 2000 and 2012.Aim
Patients and Methods
This pilot study reports the clinical outcomes
of a combination of partial subscapularis tendon transfer and small-head
hemiarthroplasty in patients with rotatator cuff arthropathy. A
total of 30 patients (30 shoulders; eight men and 22 women) with
a mean age of 74 years (55 to 84) were assessed at a mean follow-up
of 31 months (24 to 60). The inclusion criteria were painful cuff
tear arthropathy with normal deltoid function and a non-degenerative subscapularis
muscle and tendon and a preserved teres minor. Outcome was assessed using the University of California Los Angeles
score, the Japanese Orthopaedic Association score, and the Oxford
Shoulder Score. Radiographic measurements included the centre of
rotation distance and the length of the deltoid. All clinical scores were significantly improved post-operatively.
The active flexion and external rotation improved significantly
at the most recent follow-up (p <
0.035). Although the mean centre
of rotation distance changed significantly (p <
0.001), the mean
length of the deltoid did not change significantly from the pre-operative
value (p = 0.29). The change in the length of the deltoid with <
100° flexion was significantly less than that with >
100° (p <
0.001). Progressive erosion of the glenoid was seen in four patients.
No patient required revision or further surgery. A combination of partial subscapularis tendon transfer and small-head
hemiarthroplasty effectively restored function and relieved pain
in patients with rotator cuff arthropathy. Cite this article: 2015;97-B:1090–5.
Secondary fracture healing is strongly influenced by the stiffness of the bone-fixator system. Biomechanical tests are extensively used to investigate stiffness and strength of fixation devices. The stiffness values reported in the literature for locked plating, however, vary by three orders of magnitude. The aim of this study was to examine the influence that the method of restraint and load application has on the stiffness produced, the strain distribution within the bone, and the stresses in the implant for locking plate constructs. Synthetic composite bones were used to evaluate experimentally the influence of four different methods of loading and restraining specimens, all used in recent previous studies. Two plate types and three screw arrangements were also evaluated for each loading scenario. Computational models were also developed and validated using the experimental tests.Objectives
Methods
Long-term clinical outcomes for ceramic-on-ceramic (CoC) bearings
are encouraging. However, there is a risk of squeaking. Guidelines
for the orientation of the acetabular component are defined from
static imaging, but the position of the pelvis and thus the acetabular
component during activities associated with edge-loading are likely
to be very different from those measured when the patient is supine.
We assessed the functional orientation of the acetabular component. A total of 18 patients with reproducible squeaking in their CoC
hips during deep flexion were investigated with a control group
of 36 non-squeaking CoC hips. The two groups were matched for the
type of implant, the orientation of the acetabular component when
supine, the size of the femoral head, ligament laxity, maximum hip
flexion and body mass index. Aims
Patients and Methods
We sought to determine whether cobalt-chromium alloy (CoCr) femoral
stem tapers (trunnions) wear more than titanium (Ti) alloy stem
tapers (trunnions) when used in a large diameter (LD) metal-on-metal
(MoM) hip arthroplasty system. We performed explant analysis using validated methodology to
determine the volumetric material loss at the taper surfaces of
explanted LD CoCr MoM hip arthroplasties used with either a Ti alloy
(n = 28) or CoCr femoral stem (n = 21). Only 12/14 taper constructs
with a rough male taper surface and a nominal included angle close
to 5.666° were included. Multiple regression modelling was undertaken
using taper angle, taper roughness, bearing diameter (horizontal
lever arm) as independent variables. Material loss was mapped using
a coordinate measuring machine, profilometry and scanning electron
microscopy.Aims
Patients and Methods
We describe our technique and rationale using
hybrid fixation for primary total hip arthroplasty (THA) at the Hospital
for Special Surgery. Modern uncemented acetabular components have
few screw holes, or no holes, polished inner surfaces, improved
locking mechanisms, and maximised thickness and shell-liner conformity. Uncemented
sockets can be combined with highly cross-linked polyethylene liners,
which have demonstrated very low wear and osteolysis rates after
ten to 15 years of implantation. The results of cement fixation
with a smooth or polished surface finished stem have been excellent,
virtually eliminating complications seen with cementless fixation
like peri-operative femoral fractures and thigh pain. Although mid-term
results of modern cementless stems are encouraging, the long-term
data do not show reduced revision rates for cementless stems compared
with cemented smooth stems. In this paper we review the conduct
of a hybrid THA, with emphasis on pre-operative planning, surgical
technique, hypotensive epidural anaesthesia, and intra-operative
physiology. Cite this article:
There is no consensus about the best method of achieving equal
leg lengths at total hip arthroplasty (THA) in patients with Crowe
type-IV developmental dysplasia of the hip (DDH). We reviewed our
experience of a consecutive series of patients who underwent THA
for this indication. We retrospectively reviewed 78 patients (86 THAs) with Crowe
type-IV DDH, including 64 women and 14 men, with a minimum follow-up
of two years. The mean age at the time of surgery was 52.2 years
(34 to 82). We subdivided Crowe type-IV DDH into two major types
according to the number of dislocated hips, and further categorised
them into three groups according to the occurrence of pelvic obliquity
or spinal curvature. Leg length discrepancy (LLD) and functional
scores were analysed.Aims
Patients and Methods
Revision total elbow arthroplasty (TEA) is often challenging.
The aim of this study was to report on the clinical and radiological
results of revision arthroplasty of the elbow with the Latitude
TEA. Between 2006 and 2010 we used the Latitude TEA for revision in
18 consecutive elbows (17 patients); mean age 53 years (28 to 80);
14 women. A Kudo TEA was revised in 15 elbows and a Souter-Strathclyde
TEA in three. Stability, range of movement (ROM), visual analogue score (VAS)
for pain and functional scores, Elbow Functional Assessment Scale
(EFAS), the Functional Rating Index of Broberg and Morrey (FRIBM)
and the Modified Andrews’ Elbow Scoring System (MAESS) were assessed
pre-operatively and at each post-operative follow-up visit (six,
12 months and biennially thereafter). Radiographs were analysed
for loosening, fractures and dislocation. The mean follow-up was
59 months (26 to 89).Aims
Patients and Methods
Aims. To determine the effect of a change in design of a cementless
ceramic acetabular component in fixation and clinical outcome after
total hip arthroplasty. Patients and Methods. We compared 342 hips (302 patients) operated between 1999 and
2005 with a relatively smooth hydroxyapatite coated acetabular component
(group 1), and 337 hips (310 patients) operated between 2006 and
2011 using a similar acetabular component with a macrotexture on
the entire outer surface of the component (group 2). The mean age of
the patients was 53.5 (14 to 70) in group 1 and 53.0 (15 to 70)
in group 2. The mean follow-up was 12.7 years (10 to 17) for group
1 and 7.2 years (4 to 10) for group 2. Results. No hips were revised due to complications related to bearing
fracture or to stem loosening. A total of 15 acetabular components
were revised for aseptic loosening in group 1 and two in group 2.
The survival rate for acetabular component aseptic loosening at
eight years was 96.8% (95% confidence interval (CI) 94.8 to 98.7)
for group 1 and 99.2% (95% CI 98.0 to 100) for group 2. The risk
for aseptic loosening of the acetabular component was higher in group
1 (p = 0.04, Hazard Ratio (HR) 4.99), dysplastic acetabula (p =
0.01, HR 4.12), components outside Lewinnek´s zone (p <
0.001,
HR 6.13) and in those with a hip
Computer hexapod assisted orthopaedic surgery (CHAOS), is a method
to achieve the intra-operative correction of long bone deformities
using a hexapod external fixator before definitive internal fixation
with minimally invasive stabilisation techniques. The aims of this study were to determine the reliability of this
method in a consecutive case series of patients undergoing femoral
deformity correction, with a minimum six-month follow-up, to assess
the complications and to define the ideal group of patients for
whom this treatment is appropriate. The medical records and radiographs of all patients who underwent
CHAOS for femoral deformity at our institution between 2005 and
2011 were retrospectively reviewed. Records were available for all
55 consecutive procedures undertaken in 49 patients with a mean
age of 35.6 years (10.9 to 75.3) at the time of surgery.Aims
Patients and Methods
A failed total ankle arthroplasty (TAA) is often associated with
much bone loss. As an alternative to arthrodesis, the surgeon may
consider a custom-made talar component to compensate for the bone
loss. Our aim in this study was to assess the functional and radiological
outcome after the use of such a component at mid- to long-term follow-up. A total of 12 patients (five women and seven men, mean age 53
years; 36 to77) with a failed TAA and a large talar defect underwent
a revision procedure using a custom-made talar component. The design
of the custom-made components was based on CT scans and standard
radiographs, when compared with the contralateral ankle. After the
anterior talocalcaneal joint was fused, the talar component was
introduced and fixed to the body of the calcaneum.Aims
Patients and Methods
The primary aim of this study was to analyse the position of
the acetabular and femoral components in total hip arthroplasty
undertaken using an anterior surgical approach. In a prospective, single centre study, we used the EOS imaging
system to analyse the position of components following THA performed
via the anterior approach in 102 patients (103 hips) with a mean
age of 64.7 years (Aims
Patients and Methods
An uncemented hemispherical acetabular component
is the mainstay of acetabular revision and gives excellent long-term
results. Occasionally, the degree of acetabular bone loss means that a
hemispherical component will be unstable when sited in the correct
anatomical location or there is minimal bleeding host bone left
for biological fixation. On these occasions an alternative method
of reconstruction has to be used. A major column structural allograft has been shown to restore
the deficient bone stock to some degree, but it needs to be off-loaded
with a reconstruction cage to prevent collapse of the graft. The
use of porous metal augments is a promising method of overcoming
some of the problems associated with structural allograft. If the defect
is large, the augment needs to be protected by a cage to allow ingrowth
to occur. Cup-cage reconstruction is an effective method of treating
chronic pelvic discontinuity and large contained or uncontained
bone defects. This paper presents the indications, surgical techniques and
outcomes of various methods which use acetabular reconstruction
cages for revision total hip arthroplasty. Cite this article:
Sustained intra-articular delivery of pharmacological agents is an attractive modality but requires use of a safe carrier that would not induce cartilage damage or fibrosis. Collagen scaffolds are widely available and could be used intra-articularly, but no investigation has looked at the safety of collagen scaffolds within synovial joints. The aim of this study was to determine the safety of collagen scaffold implantation in a validated A total of 96 rabbits were randomly and equally assigned to four different groups: arthrotomy alone; arthrotomy and collagen scaffold placement; contracture surgery; and contracture surgery and collagen scaffold placement. Animals were killed in equal numbers at 72 hours, two weeks, eight weeks, and 24 weeks. Joint contracture was measured, and cartilage and synovial samples underwent histological analysis.Objectives
Materials and Methods
We describe the clinical and radiological results
of cementless primary total hip replacement (THR) in 25 patients
(18 women and seven men; 30 THRs) with severe developmental dysplasia
of the hip (DDH). Their mean age at surgery was 47 years (23 to
89). In all, 21 hips had Crowe type III dysplasia and nine had Crowe
type IV. Cementless acetabular components with standard polyethylene
liners were introduced as close to the level of the true acetabulum
as possible. The modular cementless S-ROM femoral component was
used with a low resection of the femoral neck. A total of 21 patients (25 THRs) were available for review at
a mean follow-up of 18.7 years (15.8 to 21.8). The mean modified
Harris hip score improved from 46 points pre-operatively to 90 at
final follow up (p <
0.001). A total of 15 patients (17 THRs; 57%) underwent revision of the
acetabular component at a mean of 14.6 years (7 to 20.8), all for
osteolysis. Two patients (two THRs) had symptomatic loosening. No
patient underwent femoral revision. Survival with revision of either
component for any indication was 81% at 15 years (95% CI 60.1 to
92.3), with 21 patients at risk. This technique may reduce the need for femoral osteotomy in severe
DDH, while providing a good long-term functional result. Cite this article:
