In total hip arthroplasty (THA), the cementless, tapered-wedge stem design contributes to achieving initial stability and providing optimal load transfer in the proximal femur. However, loading conditions on the femur following THA are also influenced by femoral structure. Therefore, we determined the effects of tapered-wedge stems on the load distribution of the femur using subject-specific finite element models of femurs with various canal shapes. We studied 20 femurs, including seven champagne flute-type femurs, five stovepipe-type femurs, and eight intermediate-type femurs, in patients who had undergone cementless THA using the Accolade TMZF stem at our institution. Subject–specific finite element (FE) models of pre- and post-operative femurs with stems were constructed and used to perform FE analyses (FEAs) to simulate single-leg stance. FEA predictions were compared with changes in bone mineral density (BMD) measured for each patient during the first post-operative year.Objectives
Patients and Methods
As adverse events related to metal on metal hip
arthroplasty have been better understood, there has been increased
interest in toxicity related to the high circulating levels of cobalt ions.
However, distinguishing true toxicity from benign elevations in
cobalt levels can be challenging. The purpose of this review is
to examine the use of cobalt alloys in total hip arthroplasty, to
review the methods of measuring circulating cobalt levels, to define
a level of cobalt which is considered pathological and to review
the pathophysiology, risk factors and treatment of cobalt toxicity.
To the best of our knowledge, there are 18 published cases where
cobalt metal ion toxicity has been attributed to the use of cobalt-chromium
alloys in hip arthroplasty. Of these cases, the great majority reported
systemic toxic reactions at serum cobalt levels more than 100 μg/L.
This review highlights some of the clinical features of cobalt toxicity,
with the goal that early awareness may decrease the risk factors
for the development of cobalt toxicity and/or reduce its severity. Take home message: Severe adverse events can arise from the release
of cobalt from metal-on-metal arthroplasties, and as such, orthopaedic
surgeons should not only be aware of the presenting problems, but
also have the knowledge to treat appropriately. Cite this article:
The April 2015 Knee Roundup360 looks at: Genetic determinants of ACL strength; TKA outcomes influenced by prosthesis; Single- or two-stage revision for infected TKA?; Arthroscopic meniscectomy: a problem that just won’t go away!; Failure in arthroscopic ACL reconstruction; ACL reconstruction in the over 50s?; Knee arthroplasty for early osteoarthritis; All inside meniscal repair; Steroids, thrombogenic markers and TKA
Unlinked, linked and convertible total elbow
arthroplasties (TEAs) are currently available. This study is the
first to report the clinical results of the convertible Latitude
TEA. This was a retrospective study of a consecutive cohort of 63
patients (69 primary TEAs) with a mean age of 60 years (23 to 87).
Between 2006 and 2008 a total of 19 men and 50 women underwent surgery.
The mean follow-up was 43 months (8 to 84). The range of movement,
function and pain all improved six months post-operatively and either
continued to improve slightly or reached a plateau thereafter. The
complication rate is similar to that reported for other TEA systems.
No loosening was seen. Remarkable is the disengagement of the radial
head component in 13 TEAs (31%) with a radial head component implanted. Implantation of both the linked and the unlinked versions of
the Latitude TEA results in improvement of function and decreased
pain, and shows high patient satisfaction at mid-term follow-up. Cite this article:
To determine whether there is any difference in infection rate
at 90 days between trauma operations performed in laminar flow and
plenum ventilation, and whether infection risk is altered following
the installation of laminar flow (LF). We assessed the impact of plenum ventilation (PV) and LF on the
rate of infection for patients undergoing orthopaedic trauma operations.
All NHS hospitals in England with a trauma theatre(s) were contacted
to identify the ventilation system which was used between April
2008 and March 2013 in the following categories: always LF, never
LF, installed LF during study period (subdivided: before, during
and after installation) and unknown. For each operation, age, gender,
comorbidity, socio-economic deprivation, number of previous trauma
operations and surgical site infection within 90 days (SSI90) were
extracted from England’s national hospital administrative Hospital
Episode Statistics database. Crude and adjusted odds ratios (OR)
were used to compare ventilation groups using hierarchical logistic
regression. Subanalysis was performed for hip hemiarthroplasties.Aims
Patients and Methods
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:
The February 2015 Knee Roundup360 looks at: Intra-operative sensors for knee balance; Mobile bearing no advantage; Death and knee replacement: a falling phenomenon; The swings and roundabouts of unicompartmental arthroplasty; Regulation, implants and innovation; The weight of arthroplasty responsibility!; BMI in arthroplasty
Fractures of the distal femur are an important cause of morbidity.
Their optimal management remains controversial. Contemporary implants
include angular-stable anatomical locking plates and locked intramedullary
nails (IMNs). We compared the long-term patient-reported functional
outcome of fixation of fractures of the distal femur using these
two methods of treatment. A total of 297 patients were retrospectively identified from
a State-wide trauma registry in Australia: 195 had been treated
with a locking plate and 102 with an IMN. Baseline characteristics
of the patients and their fractures were recorded. Health-related
quality-of-life, functional and radiographic outcomes were compared
using mixed effects regression models at six months and one year.Aims
Patients and Methods
Injectable Bromelain Solution (IBS) is a modified investigational derivate of the medical grade bromelain-debriding pharmaceutical agent (NexoBrid) studied and approved for a rapid (four-hour single application), eschar-specific, deep burn debridement. We conducted an Specially prepared medical grade IBS was injected into fresh Dupuytren’s cords excised from patients undergoing surgical fasciectomy. These cords were tested by tension-loading them to failure with the Zwick 1445 (Zwick GmbH & Co. KG, Ulm, Germany) tension testing system.Objectives
Materials and Methods
We present the medium-term clinical results of a reverse total
shoulder arthroplasty with a trabecular metal glenoid base plate. We reviewed 125 consecutive primary reverse total shoulder arthroplasties
(RTSA) implanted in 124 patients for rotator cuff arthropathy. There
were 100 women and 24 men in the study group with a mean age of
76 years (58 to 89). The mean follow-up was 32 months (24 to 60).
No patient was lost to follow-up.Aim
Patients and Methods
Modular junctions are ubiquitous in contemporary hip arthroplasty. The head-trunnion junction is implicated in the failure of large diameter metal-on-metal (MoM) hips which are the currently the topic of one the largest legal actions in the history of orthopaedics (estimated costs are stated to exceed $4 billion). Several factors are known to influence the strength of these press-fit modular connections. However, the influence of different head sizes has not previously been investigated. The aim of the study was to establish whether the choice of head size influences the initial strength of the trunnion-head connection. Ti-6Al-4V trunnions (n = 60) and two different sizes of cobalt-chromium (Co-Cr) heads (28 mm and 36 mm; 30 of each size) were used in the study. Three different levels of assembly force were considered: 4 kN; 5 kN; and 6 kN (n = 10 each). The strength of the press-fit connection was subsequently evaluated by measuring the pull-off force required to break the connection. The statistical differences in pull-off force were examined using a Kruskal–Wallis test and two-sample Mann–Whitney U test. Finite element and analytical models were developed to understand the reasons for the experimentally observed differences.Objectives
Materials and Methods
The aim of this study was to quantify the stability
of fracture-implant complex in fractures after fixation. A total
of 15 patients with an undisplaced fracture of the femoral neck,
treated with either a dynamic hip screw or three cannulated hip
screws, and 16 patients with an AO31-A2 trochanteric fracture treated
with a dynamic hip screw or a Gamma Nail, were included. Radiostereometric
analysis was used at six weeks, four months and 12 months post-operatively
to evaluate shortening and rotation. Migration could be assessed in ten patients with a fracture of
the femoral neck and seven with a trochanteric fracture. By four
months post-operatively, a mean shortening of 5.4 mm (-0.04 to 16.1)
had occurred in the fracture of the femoral neck group and 5.0 mm
(-0.13 to 12.9) in the trochanteric fracture group. A wide range
of rotation occurred in both types of fracture. Right-sided trochanteric
fractures seem more rotationally stable than left-sided fractures. This prospective study shows that migration at the fracture site
occurs continuously during the first four post-operative months,
after which stabilisation occurs. This information may allow the
early recognition of patients at risk of failure of fixation. Cite this article:
Osteochondritis Dissecans (OCD) is a condition
for which the aetiology remains unknown. It affects subchondral bone
and secondarily its overlying cartilage and is mostly found in the
knee. It can occur in adults, but is generally identified when growth
remains, when it is referred to as juvenile OCD. As the condition
progresses, the affected subchondral bone separates from adjacent
healthy bone, and can lead to demarcation and separation of its associated
articular cartilage. Any symptoms which arise relate to the stage
of the disease. Early disease without separation of the lesion results
in pain. Separation of the lesion leads to mechanical symptoms and
swelling and, in advanced cases, the formation of loose bodies. Early identification of OCD is essential as untreated OCD can
lead to the premature degeneration of the joint, whereas appropriate
treatment can halt the disease process and lead to healing. Establishing
the stability of the lesion is a key part of providing the correct
treatment. Stable lesions, particularly in juvenile patients, have
greater propensity to heal with non-surgical treatment, whereas
unstable or displaced lesions usually require surgical management. This article discusses the aetiology, clinical presentation and
prognosis of OCD in the knee. It presents an algorithm for treatment,
which aims to promote healing of native hyaline cartilage and to
ensure joint congruity. Take home message: Although there is no clear consensus as to
the best treatment of OCD, every attempt should be made to retain
the osteochondral fragment when possible as, with a careful surgical
technique, there is potential for healing even in chronic lesions Cite this article:
This study evaluated the mechanical performance, under low-load cyclic loading, of two different knotless suture anchor designs: sutures completely internal to the anchor body (SpeedScrew) and sutures external to the anchor body and adjacent to bone (MultiFIX P). Using standard suture loops pulled in-line with the rotator cuff (approximately 60°), anchors were tested in cadaveric bone and foam blocks representing normal to osteopenic bone. Mechanical testing included preloading to 10 N and cyclic loading for 500 cycles from 10 N to 60 N at 60 mm/min. The parameters evaluated were initial displacement, cyclic displacement and number of cycles and load at 3 mm displacement relative to preload. Video recording throughout testing documented the predominant source of suture displacement and the distance of ‘suture cutting through bone’.Objectives
Methods
Wrist block has been used to provide pain relief
for many procedures on the hand and wrist but its role in arthroscopy
of the wrist remains unexplored. Chondrotoxicity has been a concern
with the intra-articular infiltration of local anaesthetic. We aimed
to evaluate and compare the analgesic effect of portal and wrist
joint infiltration with a wrist block on the pain experienced by
patients after arthroscopy of the wrist. A prospective, randomised, double-blind trial was designed and
patients undergoing arthroscopy of the wrist under general anaesthesia
as a day case were recruited for the study. Levo-bupivacaine was
used for both techniques. The effects were evaluated using a ten-point
visual analogue scale, and the use of analgesic agents was also
compared. The primary outcomes for statistical analyses were the
mean pain scores and the use of analgesia post-operatively. A total of 34 patients (63% females) were recruited to the portal
and joint infiltration group and 32 patients (59% males) to the
wrist block group. Mean age was 40.8 years in the first group and
39.7 years in the second group (p >
0.05). Both techniques provided
effective pain relief in the first hour and 24 hours post-operatively
but wrist block gave better pain scores at bedtime on the day of
surgery (p = 0.007) and at 24 hours post-operatively (p = 0.006). Wrist block provides better and more reliable analgesia in patients
undergoing arthroscopy of the wrist without exposing patients to
the risk of chondrotoxicity. Cite this article:
This study reports on the first 150 consecutive
Oxford cementless unicompartmental knee arthroplasties (UKA) performed
in an independent centre (126 patients). All eligible patients had
functional scores (Oxford knee score and high activity arthroplasty
score) recorded pre-operatively and at two- and five-years of follow-up. Fluoroscopically
aligned radiographs were taken at five years and analysed for any
evidence of radiolucent lines (RLLs), subsidence or loosening. The
mean age of the cohort was 63.6 years (39 to 86) with 81 (53.1%)
males. Excellent functional scores were maintained at five years
and there were no progressive RLLs demonstrated on radiographs.
Two patients underwent revision to a total knee arthroplasty giving
a revision rate of 0.23/100 (95% confidence interval 0.03 to 0.84)
component years with overall component survivorship of 98.7% at
five years. There were a further four patients who underwent further
surgery on the same knee, two underwent bearing exchanges for dislocation
and two underwent lateral UKAs for disease progression. This was
a marked improvement from other UKAs reported in New Zealand Joint
Registry data and supports the designing centre’s early results. Cite this article:
