Aseptic loosening is a leading cause of uncemented arthroplasty failure, often accompanied by fibrotic tissue at the bone-implant interface. A biological target, neutrophil extracellular traps (NETs), was investigated as a crucial connection between the innate immune system’s response to injury, fibrotic tissue development, and proper bone healing. Prevalence of NETs in peri-implant fibrotic tissue from aseptic loosening patients was assessed. A murine model of osseointegration failure was used to test the hypothesis that inhibition (through Patient peri-implant fibrotic tissue was analyzed for NETs biomarkers. To enhance osseointegration in loose implant conditions, an innate immune system pathway (NETs) was either inhibited (Aims
Methods
We have evaluated the survivorship, outcomes, and failures of an interlocking, reconstruction-mode stem-sideplate implant used to preserve the native hip joint and achieve proximal fixation when there is little residual femur during large endoprosthetic reconstruction of the distal femur. A total of 14 patients underwent primary or revision reconstruction of a large femoral defect with a short remaining proximal femur using an interlocking, reconstruction-mode stem-sideplate for fixation after oncological distal femoral and diaphyseal resections. The implant was attached to a standard endoprosthetic reconstruction system. The implant was attached to a standard endoprosthetic reconstruction system. None of the femoral revisions were amenable to standard cemented or uncemented stem fixation. Patient and disease characteristics, surgical history, final ambulatory statusAims
Methods
To determine whether half-threaded screw holes in a new titanium locking plate design can substantially decrease the notch effects of the threads and increase the plate fatigue life. Three types (I to III) of titanium locking plates were fabricated to simulate plates used in the femur, tibia, and forearm. Two copies of each were fabricated using full- and half-threaded screw holes (called A and B, respectively). The mechanical strengths of the plates were evaluated according to the American Society for Testing and Materials (ASTM) F382-14, and the screw stability was assessed by measuring the screw removal torque and bending strength.Aims
Methods
Fixation of osteoporotic proximal humerus fractures remains challenging even with state-of-the-art locking plates. Despite the demonstrated biomechanical benefit of screw tip augmentation with bone cement, the clinical findings have remained unclear, potentially as the optimal augmentation combinations are unknown. The aim of this study was to systematically evaluate the biomechanical benefits of the augmentation options in a humeral locking plate using finite element analysis (FEA). A total of 64 cement augmentation configurations were analyzed using six screws of a locking plate to virtually fix unstable three-part fractures in 24 low-density proximal humerus models under three physiological loading cases (4,608 simulations). The biomechanical benefit of augmentation was evaluated through an established FEA methodology using the average peri-screw bone strain as a validated predictor of cyclic cut-out failure.Aims
Methods
The aim of this study is to report the results of a case series of olecranon fractures and olecranon osteotomies treated with two bicortical screws. Data was collected retrospectively for all olecranon fractures and osteotomies fixed with two bicortical screws between January 2008 and December 2019 at our institution. The following outcome measures were assessed; re-operation, complications, radiological loss of reduction, and elbow range of flexion-extension.Aims
Methods
Legg–Calvé–Perthes’ disease (LCP) is an idiopathic osteonecrosis of the femoral head that is most common in children between four and eight years old. The factors that lead to the onset of LCP are still unclear; however, it is believed that interruption of the blood supply to the developing epiphysis is an important factor in the development of the condition. Finite element analysis modelling of the blood supply to the juvenile epiphysis was investigated to understand under which circumstances the blood vessels supplying the femoral epiphysis could become obstructed. The identification of these conditions is likely to be important in understanding the biomechanics of LCP.Objectives
Methods
This study aims to evaluate if micro-CT can work as a method for the 3D assessment and analysis of cancellous bone by comparing micro-CT with undecalcified histological sections in OVX rats. The mandible and tibia of sham, ovariectomised (OVX) and zoledronate-injected ovariectomised (OVX-ZOL) rats were assessed morphometrically. Specimens were scanned by micro-CT. Undecalcified histological sections were manufactured from the specimen scanned by micro-CT and stained with haematoxylin and eosin. Bivariate linear regressions and one-way analysis of variance were undertaken for statistics using SPSS 16.0.1 software.Objectives
Methods
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
We hypothesised that the removal of the subchondral
bone plate (SCBP) for cemented acetabular component fixation in
total hip arthroplasty (THA) offers advantages over retention by
improving the cement-bone interface, without jeopardising implant
stability. We have previously published two-year follow-up data
of a randomised controlled trial (RCT), in which 50 patients with
primary osteoarthritis were randomised to either retention or removal
of the SCBP. The mean age of the retention group (n = 25, 13 males)
was 70.0 years ( Cite this article:
Cartilage repair in terms of replacement, or
regeneration of damaged or diseased articular cartilage with functional tissue,
is the ‘holy grail’ of joint surgery. A wide spectrum of strategies
for cartilage repair currently exists and several of these techniques
have been reported to be associated with successful clinical outcomes
for appropriately selected indications. However, based on respective
advantages, disadvantages, and limitations, no single strategy, or
even combination of strategies, provides surgeons with viable options
for attaining successful long-term outcomes in the majority of patients.
As such, development of novel techniques and optimisation of current techniques
need to be, and are, the focus of a great deal of research from
the basic science level to clinical trials. Translational research
that bridges scientific discoveries to clinical application involves
the use of animal models in order to assess safety and efficacy
for regulatory approval for human use. This review article provides
an overview of animal models for cartilage repair. Cite this article:
Little is known about the long-term outcome of
mobile-bearing total ankle replacement (TAR) in the treatment of end-stage
arthritis of the ankle, and in particular for patients with inflammatory
joint disease. The aim of this study was to assess the minimum ten-year
outcome of TAR in this group of patients. We prospectively followed 76 patients (93 TARs) who underwent
surgery between 1988 and 1999. No patients were lost to follow-up.
At latest follow-up at a mean of 14.8 years (10.7 to 22.8), 30 patients
(39 TARs) had died and the original TAR remained Cite this article:
Fracture repair occurs by two broad mechanisms:
direct healing, and indirect healing with callus formation. The effects
of bisphosphonates on fracture repair have been assessed only in
models of indirect fracture healing. A rodent model of rigid compression plate fixation of a standardised
tibial osteotomy was used. Ten skeletally mature Sprague–Dawley
rats received daily subcutaneous injections of 1 µg/kg ibandronate
(IBAN) and ten control rats received saline (control). Three weeks
later a tibial osteotomy was rigidly fixed with compression plating.
Six weeks later the animals were killed. Fracture repair was assessed
with mechanical testing, radiographs and histology. The mean stress at failure in a four-point bending test was significantly
lower in the IBAN group compared with controls (8.69 Nmm-2 ( Bisphosphonate treatment in a therapeutic dose, as used for risk
reduction in fragility fractures, had an inhibitory effect on direct
fracture healing. We propose that bisphosphonate therapy not be
commenced until after the fracture has united if the fracture has
been rigidly fixed and is undergoing direct osteonal healing. Cite this article:
Small animal models of fracture repair primarily investigate
indirect fracture healing via external callus formation. We present
the first described rat model of direct fracture healing. A rat tibial osteotomy was created and fixed with compression
plating similar to that used in patients. The procedure was evaluated
in 15 cadaver rats and then Objectives
Methods
Hyaline articular cartilage has been known to
be a troublesome tissue to repair once damaged. Since the introduction
of autologous chondrocyte implantation (ACI) in 1994, a renewed
interest in the field of cartilage repair with new repair techniques
and the hope for products that are regenerative have blossomed.
This article reviews the basic science structure and function of
articular cartilage, and techniques that are presently available
to effect repair and their expected outcomes.
Most animal studies indicate that early irrigation
and debridement reduce infection after an open fracture. Unfortunately,
these studies often do not involve antibiotics. Clinical studies
indicate that the timing of initial debridement does not affect
the rate of infection but these studies are observational and fraught
with confounding variables. The purpose of this study was to control
these variables using an animal model incorporating systemic antibiotics
and surgical treatment. We used a rat femur model with a defect which was contaminated
with No animal that received antibiotics and surgery two hours after
injury had detectable bacteria. When antibiotics were started at
two hours, a delay in surgical treatment from two to six hours significantly
increased the development of infection (p = 0.047). However, delaying
surgery to 24 hours increase the rate of infection, but not significantly
(p = 0.054). The timing of antibiotics had a more significant effect
on the proportion of positive samples than earlier surgery. Delaying
antibiotics to six or 24 hours had a profoundly detrimental effect
on the infection rate regardless of the timing of surgery. These
findings are consistent with the concept that bacteria progress
from a vulnerable planktonic form to a treatment-resistant biofilm.
Most surgeons favour removing forearm plates
in children. There is, however, no long-term data regarding the complications
of retaining a plate. We present a prospective case series of 82
paediatric patients who underwent plating of their forearm fracture
over an eight-year period with a minimum follow-up of two years.
The study institution does not routinely remove forearm plates.
A total of 116 plates were used: 79 one-third tubular plates and 37 dynamic
compression plates (DCP). There were 12 complications: six plates
(7.3%) were removed for pain or stiffness and there were six (7.3%)
implant-related fractures. Overall, survival of the plates was 85%
at 10 years. Cox regression analysis identified radial plates (odds
ratio (OR) 4.4, p = 0.03) and DCP fixation (OR 3.2, p = 0.02) to
be independent risk factors of an implant-related fracture. In contrast
ulnar plates were more likely to cause pain or irritation necessitating
removal (OR 5.6, p = 0.04). The complications associated with retaining a plate are different,
but do not occur more frequently than the complications following
removal of a plate in children.
We evaluated radiological hip remodelling after shelf acetabuloplasty and sought to identify prognostic factors in 25 patients with a mean age of 8.9 years (7.0 to 12.3) who had unilateral Perthes’ disease with reducible subluxation of the hip in the fragmentation stage. At a mean follow-up of 6.7 years (3.2 to 9.0), satisfactory remodelling was observed in 18 hips (72%). The type of labrum in hip abduction, as determined by intra-operative dynamic arthrography, was found to be a statistically significant prognostic factor (p = 0.012). Shelf acetabuloplasty as containment surgery seems to be best indicated for hips in which there is not marked collapse of the epiphysis and in which the extruded epiphyseal segment slips easily underneath the labrum on abduction, without imposing undue pressure on the lateral edge of the acetabulum.
We used an A significant improvement in functional weight-bearing was observed between six and 12 weeks. The significant increase in ground reaction force through the operated limb between six and 12 weeks was greater than that reported previously with morcellised graft augmented reconstructions. Histological appearance and collagen fibre orientation with bone block augmentation more closely resembled that of an intact enthesis compared with the morcellised grafting technique. Bone block augmentation of tendon-implant interfaces results in more reliable functional and histological outcomes, with a return to pre-operative levels of weight-bearing by 24 weeks.
We used a knee-sparing distal femoral endoprosthesis in young patients with malignant bone tumours of the distal femur in whom it was possible to resect the tumour and to preserve the distal femoral condyles. The proximal shaft of the endoprosthesis had a coated hydroxyapatite collar, while the distal end had hydroxyapatite-coated extracortical plates to secure it to the small residual femoral condylar fragment. We reviewed the preliminary results of this endoprosthesis in eight patients with primary bone tumours of the distal femur. Their mean age at surgery was 17.years (14 to 21). The mean follow-up was 24 months (20 to 31). At final follow-up the mean flexion at the knee was 102° (20° to 120°) and the mean Musculoskeletal Tumour Society score was 80% (57% to 96.7%). There was excellent osteointegration at the prosthesis-proximal bone interface with formation of new bone around the hydroxyapatite collar. The prosthesis allowed preservation of the knee and achieved a good functional result. Formation of new bone and remodelling at the interface make the implant more secure. Further follow-up is required to determine the long-term structural integrity of the prosthesis.
We studied bone-tendon healing using immunohistochemical methods in a rabbit model. Reconstruction of the anterior cruciate ligament was undertaken using semitendinosus tendon in 20 rabbits. Immunohistochemical evaluations were performed at one, two, four and eight weeks after the operation. The expression of CD31, RAM-11, VEGF, b-FGF, S-100 protein and collagen I, II and III in the bone-tendon interface was very similar to that in the endochondral ossification. Some of the type-III collagen in the outer layer of the graft, which was deposited at a very early phase after the operation, was believed to have matured into Sharpey-like fibres. However, remodelling of the tendon grafted into the bone tunnel was significantly delayed when compared with this ossification process. To promote healing, we believe that it is necessary to accelerate remodelling of the tendon, simultaneously with the augmentation of the ossification.
Massive endoprostheses using a cemented intramedullary stem are widely used to allow early resumption of activity after surgery for tumours. The survival of the prosthesis varies with the anatomical site, the type of prosthesis and the mode of fixation. Revision surgery is required in many cases because of aseptic loosening. Insertion of a second cemented endoprosthesis may be difficult because of the poor quality of the remaining bone, and loosening recurs quickly. We describe a series of 14 patients with triplate fixation in difficult revision or joint-sparing tumour surgery with a minimum follow-up of four years. The triplate design incorporated well within a remodelled cortex to achieve osseomechanical integration with all patients regaining their original level of function within five months. Our preliminary results suggest that this technique may provide an easy, biomechanically friendly alternative to insertion of a further device with an intramedullary stem, which has a shorter lifespan in revision or joint-sparing tumour surgery. A short segment of bone remaining after resection of a tumour will not accept an intramedullary stem, but may be soundly fixed using this method.
We compared the mechanical properties of carbon fibre composite
