In posterior stabilised total knee replacement
(TKR) a larger femoral component is sometimes selected to manage the
increased flexion gap caused by resection of the posterior cruciate
ligament. However, concerns remain regarding the adverse effect
of the increased anteroposterior dimensions of the femoral component
on the patellofemoral (PF) joint. Meanwhile, the gender-specific
femoral component has a narrower and thinner anterior flange and
is expected to reduce the PF contact force. PF contact forces were
measured at 90°, 120°, 130° and 140° of flexion using the NexGen
Legacy Posterior Stabilized (LPS)-Flex Fixed Bearing Knee system
using Standard, Upsized and Gender femoral components during TKR.
Increasing the size of the femoral component significantly increased
mean PF forces at 120°, 130° and 140° of flexion (p = 0.005, p <
0.001 and p <
0.001, respectively). No difference was found in
contact force between the Gender and the Standard components. Among
the patients who had overhang of the Standard component, mean contact
forces with the Gender component were slightly lower than those
of the Standard component, but no statistical difference was found
at 90°, 120°, 130° or 140° of flexion (p = 0.689, 0.615, 0.253 and
0.248, respectively). Upsized femoral components would increase PF forces in deep knee
flexion. Gender-specific implants would not reduce PF forces.
The purpose of this study was twofold: first,
to determine whether the five-year results of hip resurfacing arthroplasty
(HRA) in Canada justified the continued use of HRA; and second,
to identify whether greater refinement of patient selection was
warranted. This was a retrospective cohort study that involved a review
of 2773 HRAs performed between January 2001 and December 2008 at
11 Canadian centres. Cox’s proportional hazards models were used
to analyse the predictors of failure of HRA. Kaplan–Meier survival
analysis was performed to predict the cumulative survival rate at
five years. The factors analysed included age, gender, body mass
index, pre-operative hip pathology, surgeon’s experience, surgical
approach, implant sizes and implant types. The most common modes
of failure were also analysed. The 2773 HRAs were undertaken in 2450 patients: 2127 in men and
646 in women. The mean age at operation was 50.5 years ( The failure rates of HRA at five years justify the ongoing use
of this technique in men. Female gender is an independent predictor
of failure, and a higher failure rate at five years in women leads
the authors to recommend this technique only in exceptional circumstances
for women. Cite this article:
We have reviewed five adult patients treated with endoprosthetic reconstruction of the proximal radius following resection of non-traumatic lesions. The patients had a mean age of 33.4 years (20 to 60) at the time of surgery and the mean follow-up was 7.6 years (0.8 to 16). Following surgery, all elbows were clinically stable and there was 100% survivorship of the prosthesis. Evaluation of function was assessed clinically and by the Mayo Elbow Performance Score, achieving a mean of 86% (70 to 100). Results at medium-term follow-up are encouraging with regards to elbow stability, implant survivorship and functional outcome.
Compression and absolute stability are important in the management of intra-articular fractures. We compared tension band wiring with plate fixation for the treatment of fractures of the olecranon by measuring compression within the fracture. Identical transverse fractures were created in models of the ulna. Tension band wires were applied to ten fractures and ten were fixed with Acumed plates. Compression was measured using a Tekscan force transducer within the fracture gap. Dynamic testing was carried out by reproducing cyclical contraction of the triceps of 20 N and of the brachialis of 10 N. Both methods were tested on each sample. Paired The mean compression for plating was 819 N ( During simulated movements, the mean compression was reduced in both groups, with tension band wiring at −14 N ( Pre-contoured plates provide significantly greater compression than tension bands in the treatment of transverse fractures of the olecranon, both over the whole fracture and specifically at the articular side of the fracture. In tension band wiring the overall compression was reduced and articular compression remained negligible during simulated contraction of the triceps, challenging the tension band principle.
The aim of this study was to assess the accuracy
of placement of pelvic binders and to determine whether circumferential
compression at the level of the greater trochanters is the best
method of reducing a symphyseal diastasis. Patients were identified by a retrospective review of all pelvic
radiographs performed at a military hospital over a period of 30
months. We analysed any pelvic radiograph on which the buckle of
the pelvic binder was clearly visible. The patients were divided
into groups according to the position of the buckle in relation
to the greater trochanters: high, trochanteric or low. Reduction
of the symphyseal diastasis was measured in a subgroup of patients
with an open-book fracture, which consisted of an injury to the
symphysis and disruption of the posterior pelvic arch (AO/OTA 61-B/C). We identified 172 radiographs with a visible pelvic binder. Five
cases were excluded due to inadequate radiographs. In 83 (50%) the
binder was positioned at the level of the greater trochanters. A
high position was the most common site of inaccurate placement,
occurring in 65 (39%). Seventeen patients were identified as a subgroup
to assess the effect of the position of the binder on reduction
of the diastasis. The mean gap was 2.8 times greater (mean difference
22 mm) in the high group compared with the trochanteric group (p
<
0.01). Application of a pelvic binder above the level of the greater
trochanters is common and is an inadequate method of reducing pelvic
fractures and is likely to delay cardiovascular recovery in these
seriously injured patients.
This study was performed to determine whether
pure cancellous bone graft and Kirschner (K-) wire fixation were sufficient
to achieve bony union and restore alignment in scaphoid nonunion.
A total of 65 patients who underwent cancellous bone graft and K-wire
fixation were included in this study. The series included 61 men
and four women with a mean age of 34 years (15 to 72) and mean delay
to surgery of 28.7 months (3 to 240). The patients were divided
into an unstable group (A) and stable group (B) depending on the
pre-operative radiographs. Unstable nonunion was defined as a lateral
intrascaphoid angle >
45°, or a radiolunate angle >
10°. There were
34 cases in group A and 31 cases in group B. Bony union was achieved
in 30 patients (88.2%) in group A, and in 26 (83.9%) in group B
(p = 0.439). Comparison of the post-operative radiographs between
the two groups showed no significant differences in lateral intrascaphoid
angle (p = 0.657) and scaphoid length
(p = 0.670) and height (p = 0.193). The radiolunate angle was significantly
different
(p = 0.020) but the mean value in both groups was <
10°. Comparison
of the dorsiflexion and palmar flexion of movement of the wrist
and the mean Mayo wrist score at the final clinical visit in each
group showed no significant difference (p = 0.190, p = 0.587 and
p = 0.265, respectively). Cancellous bone graft and K-wire fixation
were effective in the treatment of stable and unstable scaphoid
nonunion. Cite this article:
The use of plate-and-cable constructs to treat periprosthetic fractures around a well-fixed femoral component in total hip replacements has been reported to have high rates of failure. Our aim was to evaluate the results of a surgical treatment algorithm to use these lateral constructs reliably in Vancouver type-B1 and type-C fractures. The joint was dislocated and the stability of the femoral component was meticulously evaluated in 45 type-B1 fractures. This led to the identification of nine (20%) unstable components. The fracture was considered to be suitable for single plate-and-cable fixation by a direct reduction technique if the integrity of the medial cortex could be restored. Union was achieved in 29 of 30 fractures (97%) at a mean of 6.4 months (3 to 30) in 29 type-B1 and five type-C fractures. Three patients developed an infection and one construct failed. Using this algorithm plate-and-cable constructs can be used safely, but indirect reduction with minimal soft-tissue damage could lead to shorter times to union and lower rates of complications.
In a study on ten fresh human cadavers we examined the change in the height of the intervertebral disc space, the angle of lordosis and the geometry of the facet joints after insertion of intervertebral total disc replacements. SB III Charité prostheses were inserted at L3-4, L4-5, and L5-S1. The changes studied were measured using computer navigation sofware applied to CT scans before and after instrumentation. After disc replacement the mean lumbar disc height was doubled (p <
0.001). The mean angle of lordosis and the facet joint space increased by a statistically significant extent (p <
0.005 and p = 0.006, respectively). By contrast, the mean facet joint overlap was significantly reduced (p <
0.001). Our study indicates that the increase in the intervertebral disc height after disc replacement changes the geometry at the facet joints. This may have clinical relevance.
The April 2013 Shoulder &
Elbow Roundup360 looks at: biceps, pressure and instability; chronic acromio-clavicular joint instability; depression and shoulder pain; shoulder replacement and transfusion; cuff integrity and function; iatropathic plexus injury; the accuracy of acromio-clavicular joint injection; and tennis as a risk factor for tennis elbow.
We undertook this study to determine the minimum
amount of coronoid necessary to stabilise an otherwise intact elbow
joint. Regan–Morrey types II and III, plus medial and lateral oblique
coronoid fractures, collectively termed type IV fractures, were
simulated in nine fresh cadavers. An electromagnetic tracking system
defined the three-dimensional stability of the ulna relative to
the humerus. The coronoid surface area accounts for 59% of the anterior articulation.
Alteration in valgus, internal and external rotation occurred only
with a type III coronoid fracture, accounting for 68% of the coronoid
and 40% of the entire articular surface. A type II fracture removed
42% of the coronoid articulation and 25% of the entire articular
surface but was associated with valgus and external rotational changes
only when the radial head was removed, thereby removing 67% of the
articular surface. We conclude that all type III fractures, as defined here, are
unstable, even with intact ligaments and a radial head. However,
a type II deficiency is stable unless the radial head is removed.
Our study suggests that isolated medial-oblique or lateral-oblique
fractures, and even a type II fracture with intact ligaments and
a functional radial head, can be clinically stable, which is consistent
with clinical observation.
The aim of this study was to review the number of patients operated on for traumatic disruption of the pubic symphysis who developed radiological signs of movement of the anterior pelvic metalwork during the first post-operative year, and to determine whether this had clinical implications. A consecutive series of 49 patients undergoing internal fixation of a traumatic diastasis of the pubic symphysis were studied. All underwent anterior fixation of the diastasis, which was frequently combined with posterior pelvic fixation. The fractures were divided into groups using the Young and Burgess classification for pelvic ring fractures. The different combinations of anterior and posterior fixation adopted to stabilise the fractures and the type of movement of the metalwork which was observed were analysed and related to functional outcome during the first post-operative year. In 15 patients the radiographs showed movement of the anterior metalwork, with broken or mobile screws or plates, and in six there were signs of a recurrent diastasis. In this group, four patients required revision surgery; three with anterior fixation and one with removal of anterior pelvic metalwork; the remaining 11 functioned as well as the rest of the study group. We conclude that radiological signs of movement in the anterior pelvic metalwork, albeit common, are not in themselves an indication for revision surgery.
Many radiographic techniques have been described for measuring patellar height. They can be divided into two groups: those that relate the position of the patella to the femur (direct) and those that relate it to the tibia (indirect). This article looks at the methods that have been described, the logic behind their conception and the critical analyses that have been performed to test them.
Failure of fixation is a common problem in the treatment of osteoporotic fractures around the hip. The reinforcement of bone stock or of fixation of the implant may be a solution. Our study assesses the existing evidence for the use of bone substitutes in the management of these fractures in osteoporotic patients. Relevant publications were retrieved through Medline research and further scrutinised. Of 411 studies identified, 22 met the inclusion criteria, comprising 12 experimental and ten clinical reports. The clinical studies were evaluated with regard to their level of evidence. Only four were prospective and randomised. Polymethylmethacrylate and calcium-phosphate cements increased the primary stability of the implant-bone construct in all experimental and clinical studies, although there was considerable variation in the design of the studies. In randomised, controlled studies, augmentation of intracapsular fractures of the neck of the femur with calcium-phosphate cement was associated with poor long-term results. There was a lack of data on the long-term outcome for trochanteric fractures. Because there were only a few, randomised, controlled studies, there is currently poor evidence for the use of bone cement in the treatment of fractures of the hip.
The April 2013 Knee Roundup360 looks at: graft tension and outcome; chondrocytes at the midterm; pre-operative deformity and failure; the designer effect; whether chondroitin sulphate really does work; whether ACL reconstruction is really required; analgesia after TKR; and degenerative meniscus.
Vertebral compression fractures are the most prevalent complication of osteoporosis and percutaneous vertebroplasty (PVP) has emerged as a promising addition to the methods of treating the debilitating pain they may cause. Since PVP was first reported in the literature in 1987, more than 600 clinical papers have been published on the subject. Most report excellent improvements in pain relief and quality of life. However, these papers have been based mostly on uncontrolled cohort studies with a wide variety of inclusion and exclusion criteria. In 2009, two high-profile randomised controlled trials were published in the
At our institution surgical correction of symptomatic
flat foot deformities in children has been guided by a paradigm in
which radiographs and pedobarography are used in the assessment
of outcome following treatment. Retrospective review of children
with symptomatic flat feet who had undergone surgical correction
was performed to assess the outcome and establish the relationship
between the static alignment and the dynamic loading of the foot. A total of 17 children (21 feet) were assessed before and after
correction of soft-tissue contractures and lateral column lengthening,
using standardised radiological and pedobarographic techniques for
which normative data were available. We found significantly improved static segmental alignment of
the foot, significantly improved mediolateral dimension foot loading,
and worsened fore-aft foot loading, following surgical treatment.
Only four significant associations were found between radiological
measures of static segmental alignment and dynamic loading of the foot. Weakness of the plantar flexors of the ankle was a common post-operative
finding. Surgeons should be judicious in the magnitude of lengthening
of the plantar flexors that is undertaken and use techniques that
minimise subsequent weakening of this muscle group. Cite this article:
Components from 73 failed knee replacements (TKRs) consisting of rotating-platform, mobile-bearing and fixed-bearing implants were examined to assess the patterns of wear. The patterns were divided into low-grade (burnishing, abrasion and cold flow) and high-grade (scratching, pitting/metal embedding and delamination) to assess the severity of the wear of polyethylene. The rotating-platform group had a higher incidence of low-grade wear on the upper surface compared with the fixed-bearing group. By contrast, high-grade wear comprising scratching, pitting and third-body embedding was seen on the lower surface. Linear regression analysis showed a significant correlation of the wear scores between the upper and lower surfaces of the tibial insert (R2 = 0.29, p = 0.04) for the rotating-platform group, but no significant correlation was found for the fixed-bearing counterpart. This suggests that high-grade wear patterns on the upper surface are reduced with the rotating-platform design. However, the incidence of burnishing, pitting/third-body embedding and scratching wear patterns on the lower surface was higher compared with that in the fixed-bearing knee.
Up to 20% of patients are not satisfied with the outcome following total knee replacement (TKR). This study investigated the pre- and post-operative predictors of dissatisfaction in a large cohort of patients undergoing TKR. We assessed 1217 consecutive patients between 2006 and 2008 both before operation and six months after, using the Short-form (SF)-12 health questionnaire and the Oxford Knee Score. Detailed information concerning comorbidity was also gathered. Satisfaction was measured at one year when 18.6% (226 of 1217) of patients were unsure or dissatisfied with their replacement and 81.4% (911 of 1217) were satisfied or very satisfied. Multivariate regression analysis was performed to identify independent predictors of dissatisfaction. Significant (p <
0.001) predictors at one year included the pre-operative SF-12 mental component score, depression and pain in other joints, the six-month SF-12 score and poorer improvement in the pain element of the Oxford Knee Score. Patient expectations were highly correlated with satisfaction. Satisfaction following TKR is multifactorial. Managing the expectations and mental health of the patients may reduce dissatisfaction. However, the most significant predictor of dissatisfaction is a painful total knee replacement.
The February 2013 Shoulder &
Elbow Roundup360 looks at: whether we should replace fractured shoulders; the limited evidence for shoulder fractures; cuffs and early physio; matrix proteins and cuff tears; long-term SLAP tear outcomes; suture anchors; recurrent Bankart repairs; and acromial morphology and calcific tendonitis.
The February 2013 Children’s orthopaedics Roundup360 looks at: the human genome; new RNA; cells, matrix and gene enhancement; the histology of x-rays; THR and VTE in the Danish population; potential therapeutic targets for GCT; optimising vancomycin elution from cement; and how much sleep is enough.