This was a randomised controlled trial studying
the safety of a new short metaphyseal fixation (SMF) stem. We hypothesised
that it would have similar early clinical results and micromovement
to those of a standard-length tapered Synergy metaphyseal fixation
stem. Using radiostereometric analysis (RSA) we compared the two
stems in 43 patients. A short metaphyseal fixation stem was used
in 22 patients and a Synergy stem in 21 patients. No difference
was found in the clinical outcomes pre- or post-operatively between
groups. RSA showed no significant differences two years post-operatively
in mean micromovement between the two stems (except for varus/valgus tilt
at p = 0.05) (subsidence 0.94 mm ( Cite this article:
The accurate reconstruction of hip anatomy and
biomechanics is thought to be important in achieveing good clinical
outcomes following total hip arthroplasty (THA). To this end some
newer hip designs have introduced further modularity into the design
of the femoral component such that neckshaft angle and anteversion,
which can be adjusted intra-operatively. The clinical effect of
this increased modularity is unknown. We have investigated the changes
in these anatomical parameters following conventional THA with a
prosthesis of predetermined neck–shaft angle and assessed the effect
of changes in the hip anatomy on clinical outcomes. In total, 44 patients (mean age 65.3 years (standard deviation
( The mean pre-operative neck–shaft angle was significantly increased
by 2.8° from 128° ( Cite this article:
Following the recall of modular neck hip stems
in July 2012, research into femoral modularity will intensify over
the next few years. This review aims to provide surgeons with an
up-to-date summary of the clinically relevant evidence. The development
of femoral modularity, and a classification system, is described.
The theoretical rationale for modularity is summarised and the clinical
outcomes are explored. The review also examines the clinically relevant problems
reported following the use of femoral stems with a modular neck. Joint replacement registries in the United Kingdom and Australia
have provided data on the failure rates of modular devices but cannot
identify the mechanism of failure. This information is needed to
determine whether modular neck femoral stems will be used in the
future, and how we should monitor patients who already have them implanted. Cite this article:
Revision knee arthroplasty presents a number
of challenges, not least of which is obtaining solid primary fixation
of implants into host bone. Three anatomical zones exist within
both femur and tibia which can be used to support revision implants.
These consist of the joint surface or epiphysis, the metaphysis
and the diaphysis. The methods by which fixation in each zone can
be obtained are discussed. The authors suggest that solid fixation
should be obtained in at least two of the three zones and emphasise
the importance of pre-operative planning and implant selection. Cite this article:
Stems may improve fixation and stability of components
during revision total knee replacement. However, the choice between
cemented and cementless stems is not a clear one. Cemented stems
offer several advantages in terms of versatility, mechanical stability, surgical
technique and clinical outcome over their cementless counterpart. Cite this article:
We report a multicentre prospective consecutive
study assessing the long-term outcome of the proximally hydroxyapatite
(HA)-coated ABG II monobloc femoral component in a series of 1148
hips in 1053 patients with a mean age at surgery of 64.77 years
(22 to 80) at a mean follow-up of 10.84 years (10 to 15.25). At
latest follow-up, the mean total Harris hip score was 94.7 points
( Cite this article:
Stems improve the mechanical stability of tibial
components in total knee replacement (TKR), but come at a cost of stress
shielding along their length. Their advantages include resistance
to shear, reduced tibial lift-off and increased stability by reducing
micromotion. Longer stems may have disadvantages including stress
shielding along the length of the stem with associated reduction
in bone density and a theoretical risk of subsidence and loosening, peri-prosthetic
fracture and end-of-stem pain. These features make long stems unattractive
in the primary TKR setting, but often desirable in revision surgery
with bone loss and instability. In the revision scenario, stems
are beneficial in order to convey structural stability to the construct
and protect the reconstruction of bony defects. Cemented and uncemented
long stemmed implants have different roles depending on the nature
of the bone loss involved. This review discusses the biomechanics of the design of tibial
components and stems to inform the selection of the component and
the technique of implantation.
We determined the midterm survival, incidence
of peri-prosthetic fracture and the enhancement of the width of
the femur when combining struts and impacted bone allografts in
24 patients (25 hips) with severe femoral bone loss who underwent
revision hip surgery. The pre-operative diagnosis was aseptic loosening
in 16 hips, second-stage reconstruction in seven, peri-prosthetic
fracture in one and stem fracture in one hip. A total of 14 hips
presented with an Endoklinik grade 4 defect and 11 hips a grade
3 defect. The mean pre-operative Merle D’Aubigné and Postel score
was 5.5 points (1 to 8). The survivorship was 96% (95% confidence interval 72 to 98) at
a mean of 54.5 months (36 to 109). The mean functional score was
17.3 points (16 to 18). One patient in which the strut did not completely
bypass the femoral defect was further revised using a long cemented
stem due to peri-prosthetic fracture at six months post-operatively.
The mean subsidence of the stem was 1.6 mm (1 to 3). There was no
evidence of osteolysis, resorption or radiolucencies during follow-up
in any hip. Femoral width was enhanced by a mean of 41% (19% to
82%). A total of 24 hips had partial or complete bridging of the
strut allografts. This combined biological method was associated with a favourable
survivorship, a low incidence of peri-prosthetic fracture and enhancement
of the width of the femur in revision total hip replacement in patients
with severe proximal femoral bone loss.
Structural allografts may be used to manage uncontained
bone defects in revision total knee replacement (TKR). However,
the availability of cadaver grafts is limited in some areas of Asia.
The aim of this study was to evaluate the mid-term outcome of the
use of femoral head allografts for the reconstruction of uncontained
defects in revision TKR, focusing on complications related to the
graft. We retrospectively reviewed 28 patients (30 TKRs) with Anderson
Orthopaedic Research Institute (AORI) type 3 bone defects, who underwent
revision using femoral head allografts and stemmed components. The
mean number of femoral heads used was 1.7 (1 to 3). The allograft–host
junctions were packed with cancellous autograft. At a mean follow-up of 76 months (38 to 136) the mean American
Knee Society knee score improved from 37.2 (17 to 60) pre-operatively
to 90 (83 to 100) (p <
0.001). The mean function score improved
from 26.5 (0 to 50) pre-operatively to 81 (60 to 100) (p <
0.001).
All the grafts healed to the host bone. The mean time to healing
of the graft was 6.6 months
(4 to 16). There have been no complications of collapse of the graft,
nonunion, infection or implant loosening. No revision surgery was
required. The use of femoral head allografts in conjunction with a stemmed
component and autogenous bone graft in revision TKR in patients
with uncontained bone defects resulted in a high rate of healing
of the graft with minimal complications and a satisfactory outcome.
Longer follow-up is needed to observe the evolution of the graft. Cite this article:
The February 2014 Shoulder &
Elbow Roundup360 looks at: whether arthroscopic acromioplasty is a cost-effective intervention; shockwave therapy in cuff tear; whether microfracture relieves short-term pain in cuff repair; the promising early results from L-PRF augmented cuff repairs; rehabilitation following cuff repair; supination strength following biceps tendon rupture; whether longer is better in humeral components; fatty degeneration in a rodent model; and the controversial acromioclavicular joint dislocation.
Bone preservation and physiological distribution of forces on the proximal femur are key elements in introducing a successful uncemented total hip replacement. In order to achieve this, in the mid 1990s, we developed an ultra short proximal loading custom-made component with a lateral flare, a high femoral neck osteotomy and without a diaphyseal stem. We report the outcome of 129 custom-made hydroxyapatite-coated uncemented short femoral components inserted into 109 patients between June 1995 and May 2004. The mean age of the patients was 51 years (21 to 71) and the mean follow-up was eight years (4.9 to 14.1). Bone behaviour around the implant was studied on the post-operative radiographs. The mean Harris hip score improved from 44 (8 to 66) pre-operatively to 95 (76 to 100) at final follow-up. The Western Ontario MacMaster University Osteoarthritis index was 93 of 100 at final review. None of the patients reported thigh pain. A total of five hips were revised, three for polyethylene liner exchange and two for complete revision of the acetabular component. No femoral components were revised. The radiological changes in the proximal femur were generally good, as evidenced by spot welds both on the medial and lateral aspects of the femur. No component migrated. The presence of a lateral flare and use of a high osteotomy of the femoral neck provided good clinical and radiological results. The absence of a diaphyseal portion of the stem did not impair stability.
The management of bone loss in revision replacement of the knee remains a challenge despite an array of options available to the surgeon. Bone loss may occur as a result of the original disease, the design of the prosthesis, the mechanism of failure or technical error at initial surgery. The aim of revision surgery is to relieve pain and improve function while addressing the mechanism of failure in order to reconstruct a stable platform with transfer of load to the host bone. Methods of reconstruction include the use of cement, modular metal augmentation of prostheses, custom-made, tumour-type or hinged implants and bone grafting. The published results of the surgical techniques are summarised and a guide for the management of bone defects in revision surgery of the knee is presented.
The term developmental dysplasia of the hip (DDH)
describes a spectrum of disorders that results in abnormal development
of the hip joint. If not treated successfully in childhood, these
patients may go on to develop hip symptoms and/or secondary osteoarthritis
in adulthood. In this review we describe the altered anatomy encountered
in adults with DDH along with the management options, and the challenges
associated with hip arthroscopy, osteotomies and arthroplasty for
the treatment of DDH in young adults. Cite this article:
The optimum cementing technique for the tibial
component in cemented primary total knee replacement (TKR) remains
controversial. The technique of cementing, the volume of cement
and the penetration are largely dependent on the operator, and hence
large variations can occur. Clinical, experimental and computational
studies have been performed, with conflicting results. Early implant
migration is an indication of loosening. Aseptic loosening is the
most common cause of failure in primary TKR and is the product of
several factors. Sufficient penetration of cement has been shown
to increase implant stability. This review discusses the relevant literature regarding all aspects
of the cementing of the tibial component at primary TKR. Cite this article:
We report our experience of revision total hip
replacement (THR) using the Revitan curved modular titanium fluted revision
stem in patients with a full spectrum of proximal femoral defects.
A total of 112 patients (116 revisions) with a mean age of 73.4
years (39 to 90) were included in the study. The mean follow-up
was 7.5 years (5.3 to 9.1). A total of 12 patients (12 hips) died
but their data were included in the survival analysis, and four
patients (4 hips) were lost to follow-up. The clinical outcome,
proximal bone regeneration and subsidence were assessed for 101
hips. The mean Harris Hip Score was 88.2 (45.8 to 100) after five years
and there was an increase of the mean Barnett and Nordin-Score,
a measure of the proximal bone regeneration, of 20.8 (-3.1 to 52.7).
Five stems had to be revised (4.3%), three (2.9%) showed subsidence,
five (4.3%) a dislocation and two of 85 aseptic revisions (2.3%)
a periprosthetic infection. At the latest follow-up, the survival with revision of the stem
as the endpoint was 95.7% (95% confidence interval 91.9% to 99.4%)
and with aseptic loosening as the endpoint, was 100%. Peri-prosthetic
fractures were not observed. We report excellent results with respect to subsidence, the risk
of fracture, and loosening after femoral revision using a modular
curved revision stem with distal cone-in-cone fixation. A successful
outcome depends on careful pre-operative planning and the use of
a transfemoral approach when the anatomy is distorted or a fracture
is imminent, or residual cement or a partially-secured existing
stem cannot be removed. The shortest appropriate stem should, in
our opinion, be used and secured with >
3 cm fixation at the femoral
isthmus, and distal interlocking screws should be used for additional
stability when this goal cannot be realised. Cite this article:
This was a retrospective analysis of the medium-
to long-term results of 46 TC3 Sigma revision total knee replacements
using long uncemented stems in press-fit mode. Clinical and radiological analysis took place pre-operatively,
at two years post-operatively, and at a mean follow-up of 8.5 years
(4 to 12). The mean pre-operative International Knee Society (IKS)
clinical score was 42 points (0 to 74), improving to 83.7 (52 to
100) by the final follow-up. The mean IKS score for function improved
from 34.3 points (0 to 80) to 64.2 (15 to 100) at the final follow-up.
At the final follow-up 30 knees (65.2%) had an excellent result, seven
(15.2%) a good result, one (2.2%) a medium and eight (17.4%) a poor
result. There were two failures, one with anteroposterior instability
and one with aseptic loosening. The TC3 revision knee system, when used with press-fit for long
intramedullary stems and cemented femoral and tibial components,
in both septic and aseptic revisions, results in a satisfactory
clinical and radiological outcome, and has a good medium- to long-term
survival rate.
We identified 1305 femoral impaction bone grafting revisions using the Exeter stem performed between 1989 and 2002 in 30 hospitals throughout Sweden. There were 1188 patients with a mean age of 71 years (29 to 94) followed up for between five and 18 years. The participating departments reported 70 further revisions in total, of which 57 could also be identified on the Swedish National Arthroplasty Registry. Kaplan-Meier survivorship for all causes of failure was 94.0% (95% confidence interval (CI) 92 to 96) for women and 94.7% (95% CI, 92 to 96) for men at 15 years. Survivorship at 15 years for aseptic loosening was 99.1% (95% CI 98.4 to 99.5), for infection 98.6% (95% CI 97.6 to 99.2), for subsidence 99.0% (95% CI 98.2 to 99.4) and for fracture 98.7% (95% CI 97.9 to 99.2) Statistically significant predictors of failure were the year in which revision was conducted (p <
0.001). The number of previous revisions was slightly above the level of signifance (p = 0.056). Age, gender, the length of the stem and previous septic loosening were not predictors of failure (p = 0.213, p = 0.399, p = 0.337, p = 0.687, respectively). The difference in survivorship between high- and low-volume departments was only 3% at ten years. We conclude that impaction bone grafting with the Exeter stem has an excellent long-term survivorship following revision arthroplasty. The technique of impaction grafting appears to be reliable, can be learned rapidly and produces a predictably low incidence of aseptic loosening.
The treatment of bony defects of the tibia at the time of revision total knee replacement is controversial. The place of compacted morsellised bone graft is becoming established, particularly in contained defects. It has previously been shown that the initial stability of impaction-grafted trays in the contained defects is equivalent to that of an uncemented primary knee replacement. However, there is little biomechanical evidence on which to base a decision in the treatment of uncontained defects. We undertook a laboratory-based biomechanical study comparing three methods of graft containment in segmental medial tibial defects and compared them with the use of a modular metal augment to bypass the defect. Using resin models of the proximal tibia with medial defects representing either 46% or 65% of the medial cortical rim, repair of the defect was accomplished using mesh, cement or a novel bag technique, after which impaction bone grafting was used to fill the contained defects and a tibial component was cemented in place. As a control, a cemented tibial component with modular metal augments was used in identical defects. All specimens were submitted to cyclical mechanical loading, during which cyclical and permanent tray displacement were determined. The results showed satisfactory stability with all the techniques except the bone bag method. Using metal augments gave the highest initial stability, but obviously lacked any potential for bone restoration.
Clinical experience of impaction bone grafting for revision knee arthroplasty is limited, with initial stability of the tibial tray emerging as a major concern. The length of the stem and its diameter have been altered to improve stability. Our aim was to investigate the effect of the type of stem, support of the rim and graft impaction on early stability of the tray. We developed a system for impaction grafting of trays which we used with morsellised bone in artificial tibiae. Trays with short, long thick or long thin stems were implanted, with or without support of the rim. They were cyclically loaded while measuring relative movement. Long-stemmed trays migrated 4.5 times less than short-stemmed trays, regardless of diameter. Those with support migrated 2.8 times less than those without. The migration of short-stemmed trays correlated inversely with the density of the impacted groups. That of impaction-grafted tibial trays was in the range reported for uncemented primary trays. Movements of short-stemmed trays without cortical support were largest and sensitive to the degree of compaction of the graft. If support of the rim was sufficient or a long stem was used, impacted morsellised bone graft achieved adequate initial stability.
In a retrospective study we compared 32 HINTEGRA
total ankle replacements (TARs) and 35 Mobility TARs performed between
July 2005 and May 2010, with a minimum follow-up of two years. The
mean follow-up for the HINTEGRA group was 53 months (24 to 76) and
for the Mobility group was 34 months (24 to 45). All procedures
were performed by a single surgeon. There was no significant difference between the two groups with
regard to the mean AOFAS score, visual analogue score for pain or
range of movement of the ankle at the latest follow-up. Most radiological
measurements did not differ significantly between the two groups.
However, the most common grade of heterotopic ossification (HO)
was grade 3 in the HINTEGRA group (10 of 13 TARs, 76.9%) and grade
2 in the Mobility group (four of seven TARs, 57.1%) (p = 0.025).
Although HO was more frequent in the HINTEGRA group (40.6%) than
in the Mobility group (20.0%), this was not statistically significant
(p = 0.065).The difference in peri-operative complications between
the two groups was not significant, but intra-operative medial malleolar
fractures occurred in four (11.4%) in the Mobility group; four (12.5%)
in the HINTEGRA group and one TAR (2.9%) in the Mobility group failed
(p = 0.185). Cite this article: