The August 2012 Hip &
Pelvis Roundup360 looks at: whether cemented hip replacement might be bad for your health; highly cross-linked polyethylene; iHOT-33 - a new hip outcome measure; hamstring injuries; total hip replacement; stemmed metal-on-metal THR; bipolar hemiarthroplasty, neuromuscular disease and dislocation; the high risk of secondary hemiarthroplasty; and whether we have to repair the labrum after all?
Between June 2001 and November 2008 a modified Dunn osteotomy with a surgical hip dislocation was performed in 30 hips in 28 patients with slipped capital femoral epiphysis. Complications and clinical and radiological outcomes after a mean follow-up of 3.8 years (1.0 to 8.5) were documented. Subjective outcome was assessed using the Harris hip score and the Western Ontario and McMaster Universities osteoarthritis index questionnaire. Anatomical or near-anatomical reduction was achieved in all cases. The epiphysis in one hip showed no perfusion intra-operatively and developed avascular necrosis. There was an excellent outcome in 28 hips. Failure of the implants with a need for revision surgery occurred in four hips. Anatomical reduction can be achieved by this technique, with a low risk of avascular necrosis. Cautious follow-up is necessary in order to avoid implant failure.
Revision total hip arthroplasty (THA) is challenging
when there is severe loss of bone in the proximal femur. The purpose
of this study was to evaluate the clinical and radiographic outcomes
of revision THA in patients with severe proximal femoral bone loss
treated with a fluted, tapered, modular femoral component. Between
January 1998 and December 2004, 92 revision THAs were performed
in 92 patients using a single fluted, tapered, modular femoral stem
design. Pre-operative diagnoses included aseptic loosening, infection
and peri-prosthetic fracture. Bone loss was categorised pre-operatively
as Paprosky types III-IV, or Vancouver B3 in patients with a peri-prosthetic
fracture. The mean clinical follow-up was 6.4 years (2 to 12). A
total of 47 patients had peri-operative complications, 27 of whom
required further surgery. However, most of these further operations
involved retention of a well-fixed femoral stem, and 88/92 femoral
components (97%) remained Revision THA in patients with extensive proximal femoral bone
loss using the Link MP fluted, tapered, modular stem led to a high
rate of osseointegration of the stem at mid-term follow-up. Cite this article:
The February 2014 Hip &
Pelvis Roundup360 looks at: length of stay; cementless metaphyseal fixation; mortality trends in over 400,000 total hip replacements; antibiotics in hip fracture surgery; blood supply to the femoral head after dislocation; resurfacing and THR in metal-on-metal replacement; diabetes and hip replacement; bone remodelling over two decades following hip replacement; and whether bisphosphonates affect acetabular fixation.
An experimental piglet model induces avascular necrosis (AVN)
and deformation of the femoral head but its secondary effects on
the developing acetabulum have not been studied. The aim of this
study was to assess the development of secondary acetabular deformation
following femoral head ischemia. Intracapsular circumferential ligation at the base of the femoral
neck and sectioning of the ligamentum teres were performed in three
week old piglets. MRI was then used for qualitative and quantitative
studies of the acetabula in operated and non-operated hips in eight
piglets from 48 hours to eight weeks post-surgery. Specimen photographs and
histological sections of the acetabula were done at the end of the
study. Objectives
Methods
We present the clinical results and survivorship
of consecutive 100 Birmingham Hip Resurfacings in 90 patients at
a minimum follow-up of ten years. All procedures were carried out
by an independent surgeon who commenced a prospective study in 1998.
Patients were assessed clinically using the Western Ontario and
McMaster Universities osteoarthritis index, Short-Form 36, Harris
hip score and University of California, Los Angeles activity score. Radiological
analysis was performed by an independent observer and blood metal
ion levels concentrations were measured at ten years post-operatively
in 62 patients. The median acetabular component inclination was
46.2° (34° to 59°) and anteversion 11.0° (0° to 30°). The median
chromium concentration in the unilateral group was 1.74 (0.41 to
15.23) and for the bilateral group was 2.98 (1.57 to 18.01). The
equivalent values for cobalt were 1.67 (0.54 to 20.4) and 1.88 (1.38
to 19.32). In total there were eight failures giving an overall survival
at ten years of 92% (95% confidence interval (CI) 86.7 to 97.3).
BHR in male patients had an improved survivorship of 94.6% (95%
CI 89.4 to 100) compared with females at 84.6% (95% CI 70.7 to 98.5),
but this did not reach statistical significance (p = 0.119). Four
of the nine BHRs with a bearing diameter of 42 mm failed. The overall results were consistent with data produced from other
centres in that the clinical outcome of large male patients was
extremely encouraging, whereas the survival of the smaller joints
was less satisfactory.
The December 2013 Trauma Roundup360 looks at: Re-operation for intertrochanteric hip fractures; Are twin incisions better than one round the acetabulum?; Salvage osteotomy for calcaneal fractures; Posterior dislocation; Should MRSA be covered in open fractures?; Characterising the saline load test; Has it healed: hip fractures under the spotlight; and stem cells present in atrophic non-union.
Squeaking arising from a ceramic-on-ceramic (CoC)
total hip replacement (THR) may cause patient concern and in some
cases causes patients to seek revision surgery. We performed a meta-analysis
to determine the incidence of squeaking and the incidence of revision
surgery for squeaking. A total of 43 studies including 16 828 CoC
THR that reported squeaking, or revision for squeaking, were entered
into the analysis. The incidence of squeaking was 4.2% and the incidence
of revision for squeaking was 0.2%. The incidence of squeaking in
patients receiving the Accolade femoral stem was 8.3%, and the incidence
of revision for squeaking in these patients was 1.3%. Cite this article:
We evaluated an operative technique, described
by the Exeter Hip Unit, to assist accurate introduction of the femoral
component. We assessed whether it led to a reduction in the rate
of leg-length discrepancy after total hip arthroplasty (THA). A total of 100 patients undergoing THA were studied retrospectively;
50 were undertaken using the test method and 50 using conventional
methods as a control group. The groups were matched with respect
to patient demographics and the grade of surgeon. Three observers
measured the depth of placement of the femoral component on post-operative
radiographs and measured the length of the legs. There was a strong correlation between the depth of insertion
of the femoral component and the templated depth in the test group
(R = 0.92), suggesting accuracy of the technique. The mean leg-length
discrepancy was 5.1 mm (0.6 to 21.4) pre-operatively and 1.3 mm
(0.2 to 9.3) post-operatively. There was no difference between Consultants
and Registrars as primary surgeons. Agreement between the templated
and post-operative depth of insertion was associated with reduced
post-operative leg-length discrepancy. The intra-class coefficient
was R ≥ 0.88 for all measurements, indicating high observer agreement.
The post-operative leg-length discrepancy was significantly lower
in the test group (1.3 mm) compared with the control group (6.3
mm, p <
0.001). The Exeter technique is reproducible and leads to a lower incidence
of leg-length discrepancy after THA. Cite this article:
The augmentation of fixation with bone cement
is increasingly being used in the treatment of severe osteoporotic fractures.
We investigated the influence of bone quality on the mechanics of
augmentation of plate fixation in a distal femoral fracture model
(AO 33 A3 type). Eight osteoporotic and eight non-osteoporotic femoral
models were randomly assigned to either an augmented or a non-augmented
group. Fixation was performed using a locking compression plate.
In the augmented group additionally 1 ml of bone cement was injected
into the screw hole before insertion of the screw. Biomechanical
testing was performed in axial sinusoidal loading. Augmentation significantly
reduced the cut-out distance in the osteoporotic models by about
67% (non-augmented mean 0.30 mm ( Cite this article:
We examined the morphology of mammalian hips asking whether evolution can explain the morphology of impingement in human hips. We describe two stereotypical mammalian hips, coxa recta and coxa rotunda. Coxa recta is characterised by a straight or aspherical section on the femoral head or head-neck junction. It is a sturdy hip seen mostly in runners and jumpers. Coxa rotunda has a round femoral head with ample head-neck offset, and is seen mostly in climbers and swimmers. Hominid evolution offers an explanation for the variants in hip morphology associated with impingement. The evolutionary conflict between upright gait and the birth of a large-brained fetus is expressed in the female pelvis and hip, and can explain pincer impingement in a coxa profunda. In the male hip, evolution can explain cam impingement in coxa recta as an adaptation for running.
Conventional uncemented femoral implants provide
dependable long-term fixation in patients with a wide range of functional
requirements. Yet challenges associated with proximal–distal femoral
dimensional mismatch, preservation of bone stock, and minimally
invasive approaches have led to exploration into alternative implant designs.
Short stem designs focusing on a stable metaphyseal fit have emerged
to address these issues in total hip replacement (THR). Uncemented
metaphyseal-engaging short stem implants are stable and are associated
with proximal bone remodeling closer to the metaphysis when compared
with conventional stems and they also have comparable clinical performances.
Short stem metaphyseal-engaging implants can meet the goals of a
successful THR, including tolerating a high level of patient function,
as well as durable fixation. Cite this article:
Radiostereometric analysis (RSA) can detect early
micromovement in unstable implant designs which are likely subsequently
to have a high failure rate. In 2010, the Articular Surface Replacement
(ASR) was withdrawn because of a high failure rate. In 19 ASR femoral
components, the mean micromovement over the first two years after implantation
was 0.107 mm ( We conclude that the ASR femoral component achieves initial stability
and that early migration is not the mode of failure for this resurfacing
arthroplasty.
The spiral blade modification of the Dynamic
Hip Screw (DHS) was designed for superior biomechanical fixation
in the osteoporotic femoral head. Our objective was to compare clinical
outcomes and in particular the incidence of loss of fixation. In a series of 197 consecutive patients over the age of 50 years
treated with DHS-blades (blades) and 242 patients treated with conventional
DHS (screw) for AO/OTA 31.A1 or A2 intertrochanteric fractures were
identified from a prospectively compiled database in a level 1 trauma
centre. Using propensity score matching, two groups comprising 177
matched patients were compiled and radiological and clinical outcomes
compared. In each group there were 66 males and 111 females. Mean
age was 83.6 (54 to 100) for the conventional DHS group and 83.8
(52 to 101) for the blade group. Loss of fixation occurred in two blades and 13 DHSs. None of
the blades had observable migration while nine DHSs had gross migration
within the femoral head before the fracture healed. There were two
versus four implant cut-outs respectively and one side plate pull-out
in the DHS group. There was no significant difference in mortality
and eventual walking ability between the groups. Multiple logistic
regression suggested that poor reduction (odds ratio (OR) 11.49,
95% confidence intervals (CI) 1.45 to 90.9, p = 0.021) and fixation
by DHS (OR 15.85, 95%CI 2.50 to 100.3, p = 0.003) were independent
predictors of loss of fixation. The spiral blade design may decrease the risk of implant migration
in the femoral head but does not reduce the incidence of cut-out
and reoperation. Reduction of the fracture is of paramount importance
since poor reduction was an independent predictor for loss of fixation
regardless of the implant being used. Cite this article:
Total hip replacement (THR) after acetabular
fracture presents unique challenges to the orthopaedic surgeon.
The majority of patients can be treated with a standard THR, resulting
in a very reasonable outcome. Technical challenges however include
infection, residual pelvic deformity, acetabular bone loss with
ununited fractures, osteonecrosis of bone fragments, retained metalwork,
heterotopic ossification, dealing with the sciatic nerve, and the
difficulties of obtaining long-term acetabular component fixation.
Indications for an acute THR include young patients with both femoral
head and acetabular involvement with severe comminution that cannot
be reconstructed, and the elderly, with severe bony comminution.
The outcomes of THR for established post-traumatic arthritis include
excellent pain relief and functional improvements. The use of modern
implants and alternative bearing surfaces should improve outcomes
further. Cite this article:
The femoral head receives blood supply mainly
from the deep branch of the medial femoral circumflex artery (MFCA).
In previous studies we have performed anatomical dissections of
16 specimens and subsequently visualised the arteries supplying
the femoral head in
55 healthy individuals. In this further radiological study we compared
the arterial supply of the femoral head in 35 patients (34 men and
one woman, mean age 37.1 years (16 to 64)) with a fracture/dislocation
of the hip with a historical control group of 55 hips. Using CT
angiography, we identified the three main arteries supplying the femoral
head: the deep branch and the postero-inferior nutrient artery both
arising from the MFCA, and the piriformis branch of the inferior
gluteal artery. It was possible to visualise changes in blood flow
after fracture/dislocation. Our results suggest that blood flow is present after reduction
of the dislocated hip. The deep branch of the MFCA was patent and
contrast-enhanced in 32 patients, and the diameter of this branch
was significantly larger in the fracture/dislocation group than
in the control group (p = 0.022). In a subgroup of ten patients
with avascular necrosis (AVN) of the femoral head, we found a contrast-enhanced
deep branch of the MFCA in eight hips. Two patients with no blood
flow in any of the three main arteries supplying the femoral head
developed AVN. Cite this article:
The December 2014 Hip &
Pelvis Roundup360 looks at: Sports and total hips; topical tranexamic acid and blood conservation in hip replacement; blind spots and biases in hip research; no recurrence in cam lesions at two years; to drain or not to drain?; sonication and diagnosis of implant associated infection; and biomarkers and periprosthetic infection
Third-body wear is believed to be one trigger for adverse results
with metal-on-metal (MOM) bearings. Impingement and subluxation
may release metal particles from MOM replacements. We therefore
challenged MOM bearings with relevant debris types of cobalt–chrome
alloy (CoCr), titanium alloy (Ti6Al4V) and polymethylmethacrylate
bone cement (PMMA). Cement flakes (PMMA), CoCr and Ti6Al4V particles (size range
5 µm to 400 µm) were run in a MOM wear simulation. Debris allotments
(5 mg) were inserted at ten intervals during the five million cycle
(5 Mc) test. Objectives
Methods