In this study we randomised 140 patients who
were due to undergo primary total knee arthroplasty (TKA) to have the
procedure performed using either patient-specific cutting guides
(PSCG) or conventional instrumentation (CI). The primary outcome measure was the mechanical axis, as measured
at three months on a standing long-leg radiograph by the hip–knee–ankle
(HKA) angle. This was undertaken by an independent observer who
was blinded to the instrumentation. Secondary outcome measures were
component positioning, operating time, Knee Society and Oxford knee
scores, blood loss and length of hospital stay. A total of 126 patients (67 in the CI group and 59 in the PSCG
group) had complete clinical and radiological data. There were 88
females and 52 males with a mean age of 69.3 years (47 to 84) and
a mean BMI of 28.6 kg/m2 (20.2 to 40.8). The mean HKA
angle was 178.9° (172.5 to 183.4) in the CI group and 178.2° (172.4
to 183.4) in the PSCG group (p = 0.34). Outliers were identified
in 22 of 67 knees (32.8%) in the CI group and 19 of 59 knees (32.2%)
in the PSCG group (p = 0.99). There was no significant difference
in the clinical results (p = 0.95 and 0.59, respectively). Operating time,
blood loss and length of hospital stay were not significantly reduced
(p = 0.09, 0.58 and 0.50, respectively) when using PSCG. The use of PSCG in primary TKA did not reduce the proportion
of outliers as measured by post-operative coronal alignment. Cite this article:
In arthritis of the varus knee, a high tibial
osteotomy (HTO) redistributes load from the diseased medial compartment
to the unaffected lateral compartment. We report the outcome of 36 patients (33 men and three women)
with 42 varus, arthritic knees who underwent HTO and dynamic correction
using a Garches external fixator until they felt that normal alignment
had been restored. The mean age of the patients was 54.11 years
(34 to 68). Normal alignment was achieved at a mean 5.5 weeks (3
to 10) post-operatively. Radiographs, gait analysis and visual analogue
scores for pain were measured pre- and post-operatively, at one
year and at medium-term follow-up (mean six years; 2 to 10). Failure
was defined as conversion to knee arthroplasty. Pre-operative gait analysis divided the 42 knees into two equal
groups with high (17 patients) or low (19 patients) adductor moments.
After correction, a statistically significant (p <
0.001, At final follow-up, after a mean of 15.9 years (12 to 20), there
was a survivorship of 59% (95% CI 59.6 to 68.9) irrespective of
adductor moment group, with a mean time to conversion to knee arthroplasty
of 9.5 years (3 to 18; 95% confidence interval ± 2.5). HTO remains a useful option in the medium-term for the treatment
of medial compartment osteoarthritis of the knee but does not last
in the long-term. Cite this article:
Robots have been used in surgery since the late
1980s. Orthopaedic surgery began to incorporate robotic technology
in 1992, with the introduction of ROBODOC, for the planning and
performance of total hip replacement. The use of robotic systems
has subsequently increased, with promising short-term radiological
outcomes when compared with traditional orthopaedic procedures.
Robotic systems can be classified into two categories: autonomous
and haptic (or surgeon-guided). Passive surgery systems, which represent
a third type of technology, have also been adopted recently by orthopaedic
surgeons. While autonomous systems have fallen out of favour, tactile systems
with technological improvements have become widely used. Specifically,
the use of tactile and passive robotic systems in unicompartmental
knee replacement (UKR) has addressed some of the historical mechanisms
of failure of non-robotic UKR. These systems assist with increasing
the accuracy of the alignment of the components and produce more
consistent ligament balance. Short-term improvements in clinical
and radiological outcomes have increased the popularity of robot-assisted
UKR. Robot-assisted orthopaedic surgery has the potential for improving
surgical outcomes. We discuss the different types of robotic systems
available for use in orthopaedics and consider the indication, contraindications
and limitations of these technologies.
Given the increasing number of total hip arthroplasty
procedures being performed annually, it is imperative that orthopaedic
surgeons understand factors responsible for instability. In order
to treat this potentially complex problem, we recommend correctly
classifying the type of instability present based on component position, abductor
function, impingement, and polyethylene wear. Correct classification
allows the treating surgeon to choose the appropriate revision option
that ultimately will allow for the best potential outcome. Cite this article:
The purpose of this study was to determine whether
it would be feasible to use oblique lumbar interbody fixation for
patients with degenerative lumbar disease who required a fusion
but did not have a spondylolisthesis. A series of CT digital images from 60 patients with abdominal
disease were reconstructed in three dimensions (3D) using Mimics
v10.01: a digital cylinder was superimposed on the reconstructed
image to simulate the position of an interbody screw. The optimal
entry point of the screw and measurements of its trajectory were
recorded. Next, 26 cadaveric specimens were subjected to oblique
lumbar interbody fixation on the basis of the measurements derived
from the imaging studies. These were then compared with measurements
derived directly from the cadaveric vertebrae. Our study suggested that it is easy to insert the screws for
L1/2, L2/3 and L3/4 fixation: there was no significant difference
in measurements between those of the 3-D digital images and the
cadaveric specimens. For L4/5 fixation, part of L5 inferior articular
process had to be removed to achieve the optimal trajectory of the
screw. For L5/S1 fixation, the screw heads were blocked by iliac
bone: consequently, the interior oblique angle of the cadaveric specimens
was less than that seen in the 3D digital images. We suggest that CT scans should be carried out pre-operatively
if this procedure is to be adopted in clinical practice. This will
assist in determining the feasibility of the procedure and will
provide accurate information to assist introduction of the screws. Cite this article:
Determining and accurately restoring the flexion-extension
axis of the elbow is essential for functional recovery after total
elbow arthroplasty (TEA). We evaluated the effect of morphological
features of the elbow on variations of alignment of the components
at TEA. Morphological and positioning variables were compared by
systematic CT scans of 22 elbows in 21 patients after TEA. There were five men and 16 women, and the mean age was 63 years
(38 to 80). The mean follow-up was 22 months (11 to 44). The anterior offset and version of the humeral components were
significantly affected by the anterior angulation of the humerus
(p = 0.052 and p = 0.004, respectively). The anterior offset and
version of the ulnar components were strongly significantly affected
by the anterior angulation of the ulna (p <
0.001 and p <
0.001). The closer the anterior angulation of the ulna was to the joint,
the lower the ulnar anterior offset (p = 0.030) and version of the
ulnar component (p = 0.010). The distance from the joint to the
varus angulation also affected the lateral offset of the ulnar component
(p = 0.046). Anatomical variations at the distal humerus and proximal ulna
affect the alignment of the components at TEA. This is explained
by abutment of the stems of the components and is particularly severe
when there are substantial deformities or the deformities are close
to the joint. 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:
Correct positioning and alignment of components during primary total knee replacement (TKR) is widely accepted to be an important predictor of patient satisfaction and implant durability. This retrospective study reports the effect of the post-operative mechanical axis of the lower limb in the coronal plane on implant survival following primary TKR. A total of 501 TKRs in 396 patients were divided into an aligned group with a neutral mechanical axis (± 3°) and a malaligned group where the mechanical axis deviated from neutral by >
3°. At 15 years’ follow-up, 33 of 458 (7.2%) TKRs were revised for aseptic loosening. Kaplan-Meier survival analysis showed a weak tendency towards improved survival with restoration of a neutral mechanical axis, but this did not reach statistical significance (p = 0.47). We found that the relationship between survival of a primary TKR and mechanical axis alignment is weaker than that described in a number of previous reports.
The orientation of the acetabular component can
influence both the short- and long-term outcomes of total hip replacement
(THR). We performed a prospective, randomised, controlled trial
of two groups, comprising of 40 patients each, in order to compare
freehand introduction of the component with introduction using the transverse
acetabular ligament (TAL) as a reference for anteversion. Anteversion
and inclination were measured on pelvic radiographs. With respect to anteversion, in the freehand group 22.5% of the
components were outside the safe zone With respect to inclination, in the freehand group 37.5% of the
components were outside the safe zone The transverse acetabular ligament may be used to obtain the
appropriate anteversion when introducing the acetabular component
during THR, but not acetabular component inclination. Cite this article:
Isolated patellofemoral arthritis is a common
condition and there are varying opinions on the most effective treatments.
Non-operative and operative treatments have failed to demonstrate
effective long-term treatment for those in an advanced stage of
the condition. Newer designs and increased technology in patellofemoral replacement
(PFR) have produced more consistent outcomes. This has led to a
renewed enthusiasm for this procedure. Newer PFR prostheses have
addressed the patellar maltracking issues plaguing some of the older designs.
Short-term results with contemporary prostheses and new technology
are described here. Cite this article:
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.
Primary total knee arthroplasty (TKA) is a reliable
procedure with reproducible long-term results. Nevertheless, there
are conditions related to the type of patient or local conditions
of the knee that can make it a difficult procedure. The most common
scenarios that make it difficult are discussed in this review. These
include patients with many previous operations and incisions, and
those with severe coronal deformities, genu recurvatum, a stiff knee,
extra-articular deformities and those who have previously undergone
osteotomy around the knee and those with chronic dislocation of
the patella. Each condition is analysed according to the characteristics of
the patient, the pre-operative planning and the reported outcomes. When approaching the difficult primary TKA surgeons should use
a systematic approach, which begins with the review of the existing
literature for each specific clinical situation. Cite this article:
Valid and reliable techniques for assessing performance
are essential to surgical education, especially with the emergence
of competency-based frameworks. Despite this, there is a paucity
of adequate tools for the evaluation of skills required during joint
replacement surgery. In this scoping review, we examine current
methods for assessing surgeons’ competency in joint replacement
procedures in both simulated and clinical environments. The ability
of many of the tools currently in use to make valid, reliable and
comprehensive assessments of performance is unclear. Furthermore,
many simulation-based assessments have been criticised for a lack
of transferability to the clinical setting. It is imperative that
more effective methods of assessment are developed and implemented
in order to improve our ability to evaluate the performance of skills
relating to total joint replacement. This will enable educators
to provide formative feedback to learners throughout the training
process to ensure that they have attained core competencies upon
completion of their training. This should help ensure positive patient
outcomes as the surgical trainees enter independent practice. Cite this article:
We have evaluated Four clinicians were asked to perform registration of the landmarks of the anterior pelvic plane on two cadavers. Registration was performed under four different conditions of acquisition. Errors in rotation were not significant. Version errors were significant with percutaneous methods (16.2°; p <
0.001 and 19.25° with surgical draping; p <
0.001), but not with the ultrasound acquisition (6.2°, p = 0.13). Intra-observer repeatability was achieved for all the methods. Inter-observer analysis showed acceptable agreement in the sagittal but not in the frontal plane. Ultrasound acquisition of the anterior pelvic plane was more reliable
This study used CT analysis to determine the rotational alignment of 39 painful and 26 painless fixed-bearing total knee replacements (TKRs) from a cohort of 740 NexGen Legacy posterior-stabilised and cruciate-retaining prostheses implanted between May 1996 and August 2003. The mean rotation of the tibial component was 4.3° of internal rotation (25.4° internal to 13.9° external rotation) in the painful group and 2.2° of external rotation (8.5° internal to 18.2° external rotation) in the painfree group (p = 0.024). In the painful group 17 tibial components were internally rotated more than 9° compared with none in the painfree group (p <
0.001). Additionally, six femoral components in the painful group were internally rotated more than 6° compared with none in the painfree group (p = 0.017). External rotational errors were not found to be associated with pain. Overall, 22 (56.4%) of the painful TKRs had internal rotational errors involving the femoral, the tibial or both components. It is estimated that at least 4.6% of all our TKRs have been implanted with significant internal rotational errors.
The June 2013 Knee Roundup360 looks at: iodine washout: chondrotoxic or antiseptic?; stem tip pain following revision knee replacements; metalwork removal prior to TKR; astroturf and ACL rupture; Robert Jones dressings; if thicker gloves safer; and the long leg radiograph: is it still the gold standard?
The April 2015 Research Roundup360 looks at: MCID in grip strength and distal radial fracture; Experiencing rehab in a trial setting; Electrical stimulation and nerve recovery; Molecular diagnosis of TB?; Acetabular orientation: component and arthritis; Analgesia after knee arthroplasty; Bisphosphonate-associated femoral fractures