Total knee replacement (TKR) smart tibial trials
have load-bearing sensors which will show quantitative compartment
pressure values and femoral-tibial tracking patterns. Without smart
trials, surgeons rely on feel and visual estimation of imbalance
to determine if the knee is optimally balanced. Corrective soft-tissue
releases are performed with minimal feedback as to what and how
much should be released. The smart tibial trials demonstrate graphically
where and how much imbalance is present, so that incremental releases
can be performed. The smart tibial trials now also incorporate accelerometers
which demonstrate the axial alignment. This now allows the surgeon
the option to perform a slight recut of the tibia or femur to provide
soft-tissue balance without performing soft-tissue releases. Using
a smart tibial trial to assist with soft-tissue releases or bone
re-cuts, improved patient outcomes have been demonstrated at one
year in a multicentre study of 135 patients (135 knees). Cite this article:
Fractures around total knee arthroplasties pose
a significant surgical challenge. Most can be managed with osteosynthesis
and salvage of the replacement. The techniques of fixation of these
fractures and revision surgery have evolved and so has the assessment
of outcome. This specialty update summarises the current evidence
for the classification, methods of fixation, revision surgery and
outcomes of the management of periprosthetic fractures associated
with total knee arthroplasty. Cite this article:
Extendible endoprostheses have been available for more than 30
years and have become more sophisticated with time. The latest generation
is ‘non-invasive’ and can be lengthened with an external magnetic
force. Early results have shown a worryingly high rate of complications
such as infection. This study investigates the incidence of complications
and the need for further surgery in a cohort of patients with a
non-invasive growing endoprosthesis. Between 2003 and June 2014, 50 children (51 prostheses) had a
non-invasive growing prosthesis implanted for a primary bone sarcoma.
The minimum follow-up was 24 months for those who survived. Their
mean age was 10.4 years (6 to 14). The incidence of complications
and further surgery was documented.Aims
Patients and Methods
Malrotation of the femoral component can result in post-operative complications in total knee arthroplasty (TKA), including patellar maltracking. Therefore, we used computational simulation to investigate the influence of femoral malrotation on contact stresses on the polyethylene (PE) insert and on the patellar button as well as on the forces on the collateral ligaments. Validated finite element (FE) models, for internal and external malrotations from 0° to 10° with regard to the neutral position, were developed to evaluate the effect of malrotation on the femoral component in TKA. Femoral malrotation in TKA on the knee joint was simulated in walking stance-phase gait and squat loading conditions.Objectives
Materials and Methods
Up to 40% of unicompartmental knee arthroplasty (UKA) revisions are performed for unexplained pain which may be caused by elevated proximal tibial bone strain. This study investigates the effect of tibial component metal backing and polyethylene thickness on bone strain in a cemented fixed-bearing medial UKA using a finite element model (FEM) validated experimentally by digital image correlation (DIC) and acoustic emission (AE). A total of ten composite tibias implanted with all-polyethylene (AP) and metal-backed (MB) tibial components were loaded to 2500 N. Cortical strain was measured using DIC and cancellous microdamage using AE. FEMs were created and validated and polyethylene thickness varied from 6 mm to 10 mm. The volume of cancellous bone exposed to < -3000 µε (pathological loading) and < -7000 µε (yield point) minimum principal (compressive) microstrain and > 3000 µε and > 7000 µε maximum principal (tensile) microstrain was computed.Objectives
Materials and Methods
Accurate placement of the acetabular component during total hip
arthroplasty (THA) is an important factor in the success of the
procedure. However, the reported accuracy varies greatly and is
dependent upon whether free hand or navigated techniques are used.
The aim of this study was to assess the accuracy of an instrument
system that incorporates 3D printed, patient-specific guides designed
to optimise the placement of the acetabular component. A total of 100 consecutive patients were prospectively enrolled
and the accuracy of placement of the acetabular component was measured
using post-operative CT scans.Aims
Patients and Methods
The aim of this study was to analyse the effect of altered viewing
perspectives on the measurement of the glenopolar angle (GPA) and
the differences between these measurements made on 3D CT reconstructions
and anteroposterior (AP) scapular view radiographs. The influence of the viewing perspective on the GPA was assessed,
as were the differences in the measurements of the GPA between 3D
CT reconstructions and AP scapular view radiographs in 68 cadaveric
scapulae.Aims
Materials and Methods
Studies reporting specifically on squeaking in total hip arthroplasty have focused on cementless, and not on hybrid, fixation. We hypothesised that the cement mantle of the femur might have a damping effect on the sound transmitted through the metal stem. The objective of this study was to test the effect of cement on sound propagation along different stem designs and under different fixation conditions. An Objectives
Methods
This is the first prospective study to report the pre- and post-operative
patient reported outcomes and satisfaction scores following excision
of interdigital Morton’s neuroma. Between May 2006 and April 2013, we prospectively studied 99
consecutive patients (111 feet) who were to undergo excision of
a Morton’s neuroma. There were 78 women and 21 men with a mean age
at the time of surgery of 56 years (22 to 78). Patients completed
the Manchester-Oxford Foot Questionnaire (MOXFQ), Short Form-12
(SF-12) and a supplementary patient satisfaction survey three months
pre-operatively and six months post-operatively.Aims
Patients and Methods
Femoral impaction bone grafting was first developed in 1987 using
morselised cancellous bone graft impacted into the femoral canal
in combination with a cemented, tapered, polished stem. We describe
the evolution of this technique and instrumentation since that time. Between 1987 and 2005, 705 revision total hip arthroplasties
(56 bilateral) were performed with femoral impaction grafting using
a cemented femoral stem. All surviving patients were prospectively
followed for a mean of 14.7 years (9.8 to 28.3) with no loss to
follow-up. By the time of the final review, 404 patients had died.Aims
Patients and Methods
The aim of this study was to investigate differences in pain,
range of movement function and satisfaction at three months and
one year after total knee arthroplasty (TKA) in patients with an
oblique pattern of kinematic graph of the knee and those with a
varus pattern. A total of 91 patients who underwent TKA were included in this
retrospective study. Patients (59 women and 32 men with mean age
of 68.7 years; 38.6 to 88.4) were grouped according to kinematic
graphs which were generated during navigated TKA and the outcomes
between the groups were compared.Aims
Patients and Methods
To assess the structure and extracellular matrix molecule expression of osteogenic cell sheets created via culture in medium with both dexamethasone (Dex) and ascorbic acid phosphate (AscP) compared either Dex or AscP alone. Osteogenic cell sheets were prepared by culturing rat bone marrow stromal cells in a minimal essential medium (MEM), MEM with AscP, MEM with Dex, and MEM with Dex and AscP (Dex/AscP). The cell number and messenger (m)RNA expression were assessed Objectives
Methods
To compare the structural durability of hydroxyapatite-tricalcium
phosphate (HATCP) to autologous iliac crest bone graft in calcaneal
lengthening osteotomy (CLO) for pes planovalgus in childhood. We present the interim results of ten patients (HATCP, n = 6
and autograft, n = 5) with a mean age of 11.5 years (8.2 to 14.2)
from a randomised controlled non-inferiority trial with six months
follow-up. The primary outcome was the stability of the osteotomy
as measured by radiostereometric analysis. A non-inferiority margin
of ≤ 2 mm osteotomy compression was set.Aims
Patients and Methods
The spinopelvic relationship (including pelvic incidence) has been shown to influence pelvic orientation, but its potential association with femoroacetabular impingement has not been thoroughly explored. The purpose of this study was to prove the hypothesis that decreasing pelvic incidence is associated with increased risk of cam morphology. Two matching cohorts were created from a collection of cadaveric specimens with known pelvic incidences: 50 subjects with the highest pelvic incidence (all subjects > 60°) and 50 subjects with the lowest pelvic incidence (all subjects < 35°). Femoral version, acetabular version, and alpha angles were directly measured from each specimen bilaterally. Cam morphology was defined as alpha angle > 55°. Differences between the two cohorts were analysed with a Student’s Objectives
Methods
Although gradual bone transport may permit the
restoration of large-diameter bones, complications are common owing
to the long duration of external fixation. In order to reduce such
complications, a new technique of bone transport involving the use
of an external fixator and a locking plate was devised for segmental
tibial bone defects. A total of ten patients (nine men, one woman) with a mean age
at operation of 40.4 years (16 to 64) underwent distraction osteogenesis
with a locking plate to treat previously infected post-traumatic
segmental tibial defects. The locking plate was fixed percutaneously
to bridge proximal and distal segments, and was followed by external fixation.
After docking, percutaneous screws were fixed at the transported
segment through plate holes. At the same time, bone grafting was
performed at the docking site with the external fixator removed. The mean defect size was 5.9 cm (3.8 to 9.3) and mean external
fixation index was
13.4 days/cm (11.8 to 19.5). In all cases, primary union of the
docking site and distraction callus was achieved, with an excellent
bony result. There was no recurrence of deep infection or osteomyelitis,
and with the exception of one patient with a pre-existing peroneal
nerve injury, all achieved an excellent or good functional result. With short external fixation times and low complication rates,
bone transport with a locking plate could be recommended for patients
with segmental tibial defects. Cite this article:
The purpose of this study was to compare the thickness of the hip capsule in patients with surgical hip disease, either with cam-femoroacetabular impingement (FAI) or non-FAI hip pathology, with that of asymptomatic control hips. A total of 56 hips in 55 patients underwent a 3Tesla MRI of the hip. These included 40 patients with 41 hips with arthroscopically proven hip disease (16 with cam-FAI; nine men, seven women; mean age 39 years, 22 to 58) and 25 with non-FAI chondrolabral pathology (four men, 21 women; mean age 40 years, 18 to 63) as well as 15 asymptomatic volunteers, whose hips served as controls (ten men, five women; mean age 62 years, 33 to 77). The maximal capsule thickness was measured anteriorly and superiorly, and compared within and between the three groups with a gender subanalysis using student’s Objectives
Methods
We measured the tension in the interosseous membrane
in six cadaveric forearms using an Cite this article:
The June 2015 Hip &
Pelvis Roundup360 looks at: neuraxial anaesthesia and large joint arthroplasty; revision total hip arthoplasty: factors associated with re-revision surgery; acetabular version and clinical outcomes in impingement surgery; hip precautions may be ineffective; implant selection and cost effectiveness; femoroacetabular impingement in the older age group; multiple revision in hip arthroplasty
