A retrospective study was conducted to investigate
the changes in metal ion levels in a consecutive series of Birmingham
Hip Resurfacings (BHRs) at a minimum ten-year follow-up. We reviewed
250 BHRs implanted in 232 patients between 1998 and 2001. Implant
survival, clinical outcome (Harris hip score), radiographs and serum chromium
(Cr) and cobalt (Co) ion levels were assessed. Of 232 patients, 18 were dead (five bilateral BHRs), 15 lost
to follow-up and ten had been revised. The remaining 202 BHRs in
190 patients (136 men and 54 women; mean age at surgery 50.5 years
(17 to 76)) were evaluated at a minimum follow-up of ten years (mean
10.8 years (10 to 13.6)). The overall implant survival at 13.2 years
was 92.4% (95% confidence interval 90.8 to 94.0). The mean Harris
hip score was 97.7 (median 100; 65 to 100). Median and mean ion
levels were low for unilateral resurfacings (Cr: median 1.3 µg/l,
mean
1.95 µg/l (<
0.5 to 16.2); Co: median 1.0 µg/l, mean 1.62 µg/l
(<
0.5 to 17.3)) and bilateral resurfacings (Cr: median 3.2 µg/l,
mean 3.46 µg/l (<
0.5 to 10.0); Co: median 2.3 µg/l, mean 2.66
µg/l (<
0.5 to 9.5)). In 80 unilateral BHRs with sequential ion
measurements, Cr and Co levels were found to decrease significantly
(p <
0.001) from the initial assessment at a median of six years
(4 to 8) to the last assessment at a median of 11 years (9 to 13),
with a mean reduction of 1.24 µg/l for Cr and 0.88 µg/l for Co.
Three female patients had a >
2.5 µg/l increase of Co ions, associated with
head sizes ≤ 50 mm, clinical symptoms and osteolysis. Overall, there
was no significant difference in change of ion levels between genders
(Cr, p = 0.845; Co, p = 0.310) or component sizes (Cr, p = 0.505;
Co, p = 0.370). Higher acetabular component inclination angles correlated
with greater change in ion levels (Cr, p = 0.013; Co, p = 0.002).
Patients with increased ion levels had lower Harris hip scores (p
= 0.038). In conclusion, in well-functioning BHRs the metal ion levels
decreased significantly at ten years. An increase >
2.5 µg/l was
associated with poor function. Cite this article:
Permanent growth arrest of the longer bone is
an option in the treatment of minor leg-length discrepancies. The
use of a tension band plating technique to produce a temporary epiphysiodesis
is appealing as it avoids the need for accurate timing of the procedure
in relation to remaining growth. We performed an animal study to
establish if control of growth in a long bone is possible with tension
band plating. Animals (pigs) were randomised to temporary epiphysiodesis
on either the right or left tibia. Implants were removed after ten
weeks. Both tibiae were examined using MRI at baseline, and after
ten and 15 weeks. The median interphyseal distance was significantly shorter
on the treated tibiae after both ten weeks (p = 0.04) and 15 weeks
(p = 0.04). On T1-weighted images the metaphyseal water
content was significantly reduced after ten weeks on the treated
side (p = 0.04) but returned to values comparable with the untreated
side at 15 weeks (p = 0.14). Return of growth was observed in all
animals after removal of implants. Temporary epiphysiodesis can be obtained using tension band plating.
The technique is not yet in common clinical practice but might avoid
the need for the accurate timing of epiphysiodesis. Cite this article:
We prospectively studied the benefits and risks of prolonged treatment with the Pavlik harness in infants with idiopathic developmental dysplasia of the hip. Bracing was continued as long as abduction improved. It was started at a mean age of four months (1 to 6.9). Outcome measures were the number of successful reductions, the time to reduction, the acetabular index and evidence of avascular necrosis at follow-up at one year. In 50 infants with 62 subluxated and dislocated hips (42 Graf type III and 20 type IV), 37 were reduced successfully with a mean time to reduction of 13.4 weeks ( Prolonged treatment with the Pavlik harness for developmental dysplasia of the hip over the age of one month can be beneficial in type-III hips, but it is unclear as to whether this is the optimal treatment, since it may postpone the need for closed or open reduction to a more unfavourable age. The use of the Pavlik harness in type-IV hips in this age group is questionable, but if used, prolonged bracing is not advised.
We examined the relationship between the size
of the femoral cam in femoroacetabular impingement (FAI) and acetabular
pathomorphology to establish if pincer impingement exists in patients
with a femoral cam. CT scans of 37 symptomatic impinging hips with a femoral cam
were analysed in a three-dimensional study and were compared with
34 normal hips. The inclination and version of the acetabulum as
well as the acetabular rim angle and the bony acetabular coverage
were calculated. These measurements were correlated with the size
and shape of the femoral cams. While the size of the femoral cam varied characteristically,
the acetabular morphology of the two groups was similar in terms
of version (normal mean 23° ( We found no correlation between acetabular morphology and the
severity of cam lesion and no evidence of either global or focal
over-coverage to support the diagnosis of ‘mixed’ FAI. The femoral
cam may provoke edge loading but removal of any acetabular bearing
surface when treating cam FAI might induce accelerated wear. Cite this article:
The presence of pseudotumours, which are soft-tissue masses relating to the hip, after metal-on-metal hip resurfacing arthroplasty has been associated with elevated levels of metal ions in serum, suggesting that pseudotumours occur when there is increased wear. We aimed to quantify the wear in vivo of implants revised for pseudotumours (eight) and of a control group of implants (22) revised for other reasons of failure. We found that the implant group with pseudotumours had a significantly higher rate of median linear wear of the femoral component at 8.1 μm/year (2.75 to 25.4) than the 1.79 μm/year (0.82 to 4.15; p = 0.002) of the non-pseudotumour group. For the acetabular component a significantly higher rate of median linear wear of 7.36 μm/year (1.61 to 24.9) was observed in the pseudotumour group compared with 1.28 μm/year (0.81 to 3.33, p = 0.001) in the other group. Wear of the acetabular component in the pseudotumour group always involved the edge of the implant, indicating that edge-loading had occurred. Our findings are the first direct evidence that pseudotumour is associated with increased wear at the metal-on-metal articulation. Furthermore, edge-loading with the loss of fluid-film lubrication may be an important mechanism of generation of wear in patients with a pseudotumour.
Pseudotumour is a rare but important complication of metal-on-metal hip resurfacing that occurs much more commonly in women than in men. We examined the relationship between head-neck ratio (HNR) and pseudotumour formation in 18 resurfaced hips (18 patients) revised for pseudotumour and 42 asymptomatic control resurfaced hips (42 patients). Patients in whom pseudotumour formation had occurred had higher pre-operative HNR than the control patients (mean 1.37 ( We suggest that reducing the size of the femoral head, made possible by a high pre-operative HNR, increases the risk of impingement and edge loading, and may contribute to high wear and pseudotumour formation. As the incidence of pseudotumour is low in men, it appears safe to perform resurfacing in men. However, this study suggests that it is also reasonable to resurface in women with a pre-operative HNR ≤ 1.3.
In 100 patients the fulcrum axis which is the line connecting the anterior tip of the coracoid and the posterolateral angle of the acromion, was used to position true anteroposterior radiographs of the shoulder. This method was then compared with the conventional radiological technique in a further 100 patients. Three orthopaedic surgeons counted the number of images without overlap between the humeral head and glenoid and calculated the amount of the glenoid surface visible in each radiograph. The analysis was repeated for intraobserver reliability. The learning curves of both techniques were studied. The amount of free visible glenoid space was significantly higher using the fulcrum-axis method (64 vs 31) and the comparable glenoid size increased significantly (8.56 vs 6.47). Thus the accuracy of the anteroposterior radiographs of the shoulder is impaired by using this technique. The intra and interobserver reliability showed a high consistency. No learning curve was observed for either technique.
The goals of this study were: 1) to determine if high-fat diet
(HFD) feeding in female mice would negatively impact biomechanical
and histologic consequences on the Achilles tendon and quadriceps
muscle; and 2) to investigate whether exercise and branched-chain
amino acid (BCAA) supplementation would affect these parameters
or attenuate any negative consequences resulting from HFD consumption. We examined the effects of 16 weeks of 60% HFD feeding, voluntary
exercise (free choice wheel running) and BCAA administration in
female C57BL/6 mice. The Achilles tendons and quadriceps muscles
were removed at the end of the experiment and assessed histologically
and biomechanically.Objectives
Methods
The April 2013 Wrist &
Hand Roundup360 looks at: whether botox is just for Hollywood; supercharging nerve repairs; YouTube research; options for Keinbock’s disease; volar plates; driving and plasters; symptomatic radial malunion; and MRI and acute scaphoid fractures.
The purpose of this study was to evaluate the
risk of late displacement after the treatment of distal radial fractures with
a locking volar plate, and to investigate the clinical and radiological
factors that might correlate with re-displacement. From March 2007
to October 2009, 120 of an original cohort of 132 female patients
with unstable fractures of the distal radius were treated with a
volar locking plate, and were studied over a follow-up period of
six months. In the immediate post-operative and final follow-up
radiographs, late displacement was evaluated as judged by ulnar
variance, radial inclination, and dorsal angulation. We also analysed
the correlation of a variety of clinical and radiological factors
with re-displacement. Ulnar variance was significantly overcorrected
(p <
0.001) while radial inclination and dorsal angulation were
undercorrected when compared statistically (p <
0.001) with the unaffected
side in the immediate post-operative stage. During follow-up, radial
shortening and dorsal angulation progressed statistically, but none
had a value beyond the acceptable range. Bone mineral density measured
at the proximal femur and the position of the screws in the subchondral
region, correlated with slight progressive radial shortening, which
was not clinically relevant. Volar locking plating of distal radial fractures is a reliable
form of treatment without substantial late displacement. Cite this article:
Extensive limb lengthening may be indicated in achondroplastic patients who wish to achieve a height within the normal range for their population. However, increasing the magnitude of lengthening is associated with further complications particularly adjacent joint stiffness and fractures. We studied the relationship between the magnitude of femoral lengthening and callus pattern, adjacent joint stiffness and fracture of the regenerate bone in 40 femoral lengthenings in 20 achondroplastic patients. They were divided into two groups; group A had lengthening of less than 50% and group B of more than 50% of their initial femoral length. The patterns of radiological callus formation were classified according to shape, type and features. The incidence of callus features, knee stiffness and regenerate bone fracture were analysed in the two groups. Group B was associated with an increased incidence of concave, lateral and central callus shapes, adjacent joint and stiffness and fracture. Statistically, the incidence of stiffness in adjacent joints and regenerate bone fracture was significantly associated with the magnitude of lengthening. We suggest that careful radiological assessment of the patterns of callus formation is a useful method for the evaluation and monitoring of regenerate bone.
This study examined the relationship between the cross-over sign and the true three-dimensional anatomical version of the acetabulum. We also investigated whether in true retroversion there is excessive femoral head cover anteriorly. Radiographs of 64 hips in patients being investigated for symptoms of femoro-acetabular impingement were analysed and the presence of a cross-over sign was documented. CT scans of the same hips were analysed to determine anatomical version and femoral head cover in relation to the anterior pelvic plane after correcting for pelvic tilt. The sensitivity and specificity of the cross-over sign were 92% and 55%, respectively for identifying true acetabular retroversion. There was no significant difference in total cover between normal and retroverted cases. Anterior and posterior cover were, however, significantly different (p <
0.001 and 0.002). The cross-over sign was found to be sensitive but not specific. The results for femoral head cover suggest that retroversion is characterised by posterior deficiency but increased cover anteriorly.
Ensuring correct rotation of the femoral component
is a challenging aspect of patellofemoral replacement surgery. Rotation
equal to the epicondylar axis or marginally more external rotation
is acceptable. Internal rotation is associated with poor outcomes.
This paper comprises two studies evaluating the use of the medial
malleolus as a landmark to guide rotation. We used 100 lower-leg anteroposterior radiographs to evaluate
the reliability of the medial malleolus as a landmark. Assessment
was made of the angle between the tibial shaft and a line from the
intramedullary rod entry site to the medial malleolus. The femoral
cut was made in ten cadaver knees using the inferior tip of the
medial malleolus as a landmark for rotation. Rotation of the cut
relative to the anatomical epicondylar axis was assessed using CT.
The study of radiographs found the position of the medial malleolus
relative to the tibial axis is consistent. Using the inferior tip
of the medial malleolus in the cadaver study produced a mean external
rotation of 1.6° (0.1° to 3.7°) from the anatomical epicondylar
axis. Using the inferior tip of the medial malleolus to guide the
femoral cutting jig avoids internal rotation and introduces an acceptable
amount of external rotation of the femoral component.
We reviewed 87 patients who had undergone expansive cervical laminoplasty between 1999 and 2005. These were divided into two groups: those who had diabetes mellitus and those who did not. There were 31 patients in the diabetes group and 56 in the control group. Although a significant improvement in the Japanese Orthopaedic Association score was seen in both groups, the post-operative recovery rate in the control group was better than that of the diabetic group. The patients’ age and symptom duration adversely affected the rate of recovery in the diabetic group only. Smoking did not affect the outcome in either group. A logistic regression analysis found diabetes and signal changes in the spinal cord on MRI to be significant risk factors for a poor outcome (odds ratio 2.86, 3.02, respectively). Furthermore, the interaction of diabetes with smoking and/or age increased this risk. We conclude that diabetes mellitus, or the interaction of this with old age, can adversely affect outcome after cervical laminoplasty. However, smoking alone cannot be regarded as a risk factor.
We assessed the reliability, accuracy and variability of closed-wedge high tibial osteotomy (HTO) using computer-assisted surgery compared to the conventional technique. A total of 50 closed-wedge HTO procedures were performed using the navigation system, and compared with 50 HTOs that had been performed with the conventional technique. In the navigation group, the mean mechanical axis prior to osteotomy was varus 8.2°, and the mean mechanical axis following fixation was valgus 3.6°. On the radiographs the mean pre-operative mechanical axis was varus 7.3°, and the mean post-operative mechanical axis was valgus 2.1°. There was a positive correlation between the measured data taken under navigation and by radiographs (r >
0.3, p <
0.05). The mean correction angle was significantly more accurate in the navigation group (p <
0.002). The variability of the correction was significantly lower in the navigation group (2.3°
Noise generation has been reported with ceramic-on-ceramic
articulations in total hip replacement (THR). This study evaluated
208 consecutive Delta Motion THRs at a mean follow-up of 21 months
(12 to 35). There were 141 women and 67 men with a mean age of 59
years (22 to 84). Patients were reviewed clinically and radiologically,
and the incidence of noise was determined using a newly described
assessment method. Noise production was examined against range of
movement, ligamentous laxity, patient-reported outcome scores, activity
level and orientation of the acetabular component. There were 143
silent hips (69%), 22 (11%) with noises other than squeaking, 17
(8%) with unreproducible squeaking and 26 (13%) with reproducible
squeaking. Hips with reproducible squeaking had a greater mean range
of movement (p <
0.001) and mean ligament laxity (p = 0.004), smaller
median head size (p = 0.01) and decreased mean acetabular component
inclination (p = 0.02) and anteversion angle (p = 0.02) compared
with the other groups. There was no relationship between squeaking
and age (p = 0.13), height (p = 0.263), weight (p = 0.333), body
mass index (p = 0.643), gender (p = 0.07) or patient outcome score
(p = 0.422). There were no revisions during follow-up. Despite the
surprisingly high incidence of squeaking, all patients remain satisfied
with their hip replacement. Cite this article:
From a search of MRI reports on knees, 20 patients were identified with evidence of early anteromedial osteoarthritis without any erosion of bone and a control group of patients had an acute rupture of the anterior cruciate ligament. The angle formed between the extension and flexion facets of the tibia, which is known as the extension facet angle, was measured on a sagittal image at the middle of the medial femoral condyle. The mean extension facet angle in the control group was 14° (3° to 25°) and was unrelated to age (Spearman’s rank coefficient, p = 0.30, r = 0.13). The mean extension facet angle in individuals with MRI evidence of early anteromedial osteoarthritis was 19° (13° to 26°, SD 4°). This difference was significant (Mann-Whitney U test, p <
0.001). A wide variation in the extension facet angle was found in the normal control knees and an association between an increased extension facet angle and MRI evidence of early anteromedial osteoarthritis. Although a causal link has not been demonstrated, we postulate that a steeper extension facet angle might increase the duration of loading on the extension facet during the stance phase of gait, and that this might initiate failure of the articular cartilage.
The aim of this study was to determine the association
between the Oxford knee score (OKS) and direct assessment of outcome,
and to examine how this relationship varied at different time-points
following total knee replacement (TKR). Prospective data consisting
of the OKS, numerical rating scales for ‘worst pain’ and ‘perceived
mean daily pain’, timed functional assessments (chair rising, stairs
and walking ability), goniometry and lower limb power were recorded
for 183 patients pre-operatively and at six, 26 and 52 weeks post-operatively.
The OKS was influenced primarily by the patient’s level of pain
rather than objective functional assessments. The relationship between report
of outcome and direct assessment changed over time: R2 =
35% pre-operatively, 44% at six weeks, 57% at 26 weeks and 62% at
52 weeks. The relationship between assessment of performance and report
of performance improved as the patient’s report of pain diminished,
suggesting that patients’ reporting of functional outcome after
TKR is influenced more by their pain level than their ability to
accomplish tasks.
The October 2012 Hip &
Pelvis Roundup360 looks at: diagnosing the infected hip replacement; whether tranexamic acid has a low complication rate; the relationship between poor cementing technique and early failure of resurfacing; debridement and retention for the infected replacement; triple-tapered stems and bone mineral density; how early discharge can be bad for your sleep; an updated QFracture algorithm to predict the risk of an osteoporotic fracture; and local infiltration analgesia and total hip replacement.
Eighteen hip fusions were converted to total
hip replacements. A constrained acetabular liner was used in three hips.
Mean follow up was five years (two to 15). Two (11%) hips failed,
requiring revision surgery and two patients (11%) had injury to
the peroneal nerve. Heterotopic ossification developed in seven
(39%) hips, in one case resulting in joint ankylosis. No hips dislocated. Conversion of hip fusion to hip replacement carries an increased
risk of heterotopic ossification and neurological injury. We advise
prophylaxis against heterotropic ossification. When there is concern
about hip stability we suggest that the use of a constrained acetabular
liner is considered. Despite the potential for complications, this procedure
had a high success rate and was effective in restoring hip function.