The literature on fracture repair has been reviewed. The traditional concepts of delayed and nonunion have been examined in terms of the phased and balanced anabolic and catabolic responses in bone repair. The role of medical manipulation of these inter-related responses in the fracture healing have been considered.
The reduced stability of hydroxyapatite (HA)-coated implants in osteopenic conditions is considered to be a major problem. We therefore developed a model of a boosted cementless implantation in osteopenic rats. Twelve-week-old rats were either ovariectomised (OVX) or sham-operated (SO), and after 24 weeks plain or HA-coated implants were inserted. They were treated with either a prostaglandin EP4 receptor agonist (ONO-4819) or saline for one month. The EP4 agonist considerably improved the osteoporosis in the OVX group. Ultrastructural analysis and mechanical testing showed an improvement in the implant-bone attachment in the HA-coated implants, which was further enhanced by the EP4 agonist. Although the stability of the HA-coated implants in the saline-treated OVX rats was less than in the SO normal rats, the administration of the EP4 agonist significantly compensated for this shortage. Our results showed that the osteogenic effect of the EP4 agonist augmented the osteoconductivity of HA and significantly improved the stability of the implant-bone attachment in the osteoporotic rat model.
The most frequent cause of failure after total
hip replacement in all reported arthroplasty registries is peri-prosthetic
osteolysis. Osteolysis is an active biological process initiated
in response to wear debris. The eventual response to this process
is the activation of macrophages and loss of bone. Activation of macrophages initiates a complex biological cascade
resulting in the final common pathway of an increase in osteolytic
activity. The biological initiators, mechanisms for and regulation
of this process are beginning to be understood. This article explores current
concepts in the causes of, and underlying biological mechanism resulting
in peri-prosthetic osteolysis, reviewing the current basic science
and clinical literature surrounding the topic.
Surgical marking during tendon surgery is often used for technical
and teaching purposes. This study investigates the effect of a gentian
violet ink marker pen, a common surgical marker, on the viability
of the tissue and cells of tendon.
Objectives
Methods
Ovine articular chondrocytes were isolated from cartilage biopsy and culture expanded All defects were assessed using the International Cartilage Repair Society (ICRS) classification. Those treated with ACFC, ACI and AF exhibited median scores which correspond to a nearly-normal appearance. On the basis of the modified O’Driscoll histological scoring scale, ACFC implantation significantly enhanced cartilage repair compared to ACI and AF. Using scanning electron microscopy, ACFC and ACI showed characteristic organisation of chondrocytes and matrices, which were relatively similar to the surrounding adjacent cartilage. Implantation of ACFC resulted in superior hyaline-like cartilage regeneration when compared with ACI. If this result is applicable to humans, a better outcome would be obtained than by using conventional ACI.
The types of explosive devices used in warfare
and the pattern of war wounds have changed in recent years. There has,
for instance, been a considerable increase in high amputation of
the lower limb and unsalvageable leg injuries combined with pelvic
trauma. The conflicts in Iraq and Afghanistan prompted the Department
of Military Surgery and Trauma in the United Kingdom to establish
working groups to promote the development of best practice and act
as a focus for research. In this review, we present lessons learnt in the initial care
of military personnel sustaining major orthopaedic trauma in the
Middle East.
In patients with traumatic brain injury and fractures
of long bones, it is often clinically observed that the rate of bone
healing and extent of callus formation are increased. However, the
evidence has been unconvincing and an association between such an
injury and enhanced fracture healing remains unclear. We performed
a retrospective cohort study of 74 young adult patients with a mean
age of 24.2 years (16 to 40) who sustained a femoral shaft fracture
(AO/OTA type 32A or 32B) with or without a brain injury. All the
fractures were treated with closed intramedullary nailing. The main
outcome measures included the time required for bridging callus
formation (BCF) and the mean callus thickness (MCT) at the final
follow-up. Comparative analyses were made between the 20 patients
with a brain injury and the 54 without brain injury. Subgroup comparisons
were performed among the patients with a brain injury in terms of
the severity of head injury, the types of intracranial haemorrhage
and gender. Patients with a brain injury had an earlier appearance
of BCF
(p <
0.001) and a greater final MCT value (p <
0.001) than
those without. There were no significant differences with respect
to the time required for BCF and final MCT values in terms of the
severity of head injury (p = 0.521 and p = 0.153, respectively),
the types of intracranial haemorrhage (p = 0.308 and p = 0.189,
respectively) and gender (p = 0.383 and
p = 0.662, respectively). These results confirm that an injury to the brain may be associated
with accelerated fracture healing and enhanced callus formation.
However, the severity of the injury to the brain, the type of intracranial
haemorrhage and gender were not statistically significant factors
in predicting the rate of bone healing and extent of final callus formation.
This study evaluated the effect of limb lengthening
on longitudinal growth in patients with achondroplasia. Growth of
the lower extremity was assessed retrospectively by serial radiographs
in 35 skeletally immature patients with achondroplasia who underwent
bilateral limb lengthening (Group 1), and in 12 skeletally immature
patients with achondroplasia who did not (Group 2). In Group 1,
23 patients underwent only tibial lengthening (Group 1a) and 12 patients
underwent tibial and femoral lengthening sequentially (Group 1b). The mean lengthening in the tibia was 9.2 cm (59.5%) in Group
1a, and 9.0 cm (58.2%) in the tibia and 10.2 cm (54.3%) in the femur
in Group 1b. The mean follow-up was 9.3 years (8.6 to 10.3). The
final mean total length of lower extremity in Group 1a was 526.6
mm (501.3 to 552.9) at the time of skeletal maturity and 610.1 mm
(577.6 to 638.6) in Group 1b, compared with 457.0 mm (411.7 to 502.3)
in Group 2. However, the mean actual length, representing the length
solely grown from the physis without the length of distraction,
showed that there was a significant disturbance of growth after
limb lengthening. In Group 1a, a mean decrease of 22.4 mm (21.3
to 23.1) (4.9%) was observed in the actual limb length when compared
with Group 2, and a greater mean decrease of 38.9 mm (37.2 to 40.8)
(8.5%) was observed in Group 1b when compared with Group 2 at skeletal
maturity. In Group 1, the mean actual limb length was 16.5 mm (15.8 to
17.2) (3.6%) shorter in Group 1b when compared with Group 1a at
the time of skeletal maturity. Premature physeal closure was seen
mostly in the proximal tibia and the distal femur with relative
preservation of proximal femur and distal tibia. We suggest that significant disturbance of growth can occur after
extensive limb lengthening in patients with achondroplasia, and
therefore, this should be included in pre-operative counselling
of these patients and their parents.
This study aims to assess the correlation of CT-based structural
rigidity analysis with mechanically determined axial rigidity in
normal and metabolically diseased rat bone. A total of 30 rats were divided equally into normal, ovariectomized,
and partially nephrectomized groups. Cortical and trabecular bone
segments from each animal underwent micro-CT to assess their average
and minimum axial rigidities using structural rigidity analysis.
Following imaging, all specimens were subjected to uniaxial compression
and assessment of mechanically-derived axial rigidity.Objectives
Methods
For over a decade, bisphosphonate administration
has evolved and become the cornerstone of the prevention and treatment
of fragility fractures. Millions of post-menopausal women have relied
on, and continue to depend on, the long-acting, bone density-maintaining
pharmaceutical drug to prevent low-energy fractures. In return,
we have seen the number of fragility fractures decrease, along with
associated costs and emotional benefits. However, with any drug,
there are often concerns with side effects and complications, and
this unique drug class is seeing one such complication in atypical
subtrochanteric femoral fracture, counterproductive to that which
it was designed to prevent. This has created concern over long-term
bisphosphonate administration and its potential link to these atypical
fractures. There is controversial evidence surrounding such a definitive
link, and no protocol for managing these fractures. This review offers the latest information regarding this rare
but increasingly controversial adverse effect and its potential
connection to one of the most successful forms of treatment that
is available for the management of fragility fractures.
This study reports the application of a novel method for quantitatively determining differences in the mechanical properties of healthy and torn rotator cuff tissues. In order to overcome problems of stress risers at the grip-tendon interface that can obscure mechanical measurements of small tendons, we conducted our investigation using dynamic shear analysis. Rotator cuff tendon specimens were obtained from 100 patients during shoulder surgery. They included 82 differently sized tears and 18 matched controls. We subjected biopsy samples of 3 mm in diameter to oscillatory deformation under compression using dynamic shear analysis. The storage modulus (G’) was calculated as an indicator of mechanical integrity. Normal tendons had a significantly higher storage modulus than torn tendons, indicating that torn tendons are mechanically weaker than normal tendons (p = 0.003). Normal tendons had a significantly higher mean shear modulus than tendons with massive tears (p <
0.01). Dynamic shear analysis allows the determination of shear mechanical properties of small tissue specimens obtained intra-operatively that could not be studied by conventional methods of tensile testing. These methods could be employed to investigate other musculoskeletal tissues. This pilot study provides some insight into mechanisms that might contribute to the failure of repair surgery, and with future application could help direct the most appropriate treatment for specific rotator cuff tears.
Two-stage revision surgery for infected total knee replacement offers the highest rate of success for the elimination of infection. The use of articulating antibiotic-laden cement spacers during the first stage to eradicate infection also allows protection of the soft tissues against excessive scarring and stiffness. We have investigated the effect of cyclical loading of cement spacers on the elution of antibiotics. Femoral and tibial spacers containing vancomycin at a constant concentration and tobramycin of varying concentrations were studied The elution of tobramycin increased proportionately with its concentration in cement and was significantly higher at all sampling times from five minutes to 1680 minutes in loaded components compared with the control group (p = 0.021 and p = 0.003, respectively). A similar trend was observed with elution of vancomycin, but this failed to reach statistical significance at five, 1320 and 1560 minutes (p = 0.0508, p = 0.067 and p = 0.347, respectively). However, cyclically loaded and control components showed an increased elution of vancomycin with increasing tobramycin concentration in the specimens, despite all components having the same vancomycin concentration. The concentration of tobramycin influences both tobramycin and vancomycin elution from bone cement. Cyclical loading of the cement spacers enhanced the elution of vancomycin and tobramycin.
Failure of bone repair is a challenging problem in the management of fractures. There is a limited supply of autologous bone grafts for treating nonunions, with associated morbidity after harvesting. There is need for a better source of cells for repair. Mesenchymal stem cells (MSCs) hold promise for healing of bone because of their capacity to differentiate into osteoblasts and their availability from a wide variety of sources. Our review aims to evaluate the available clinical evidence and recent progress in strategies which attempt to use autologous and heterologous MSCs in clinical practice, including genetically-modified MSCs and those grown on scaffolds. We have compared various procedures for isolating and expanding a sufficient number of MSCs for use in a clinical setting. There are now a number of clinical studies which have shown that implantation of MSCs is an effective, safe and durable method for aiding the repair and regeneration of bone.
Bacterial infection in orthopaedic surgery can be devastating, and is associated with significant morbidity and poor functional outcomes, which may be improved if high concentrations of antibiotics can be delivered locally over a prolonged period of time. The two most widely used methods of doing this involve antibiotic-loaded polymethylmethacrylate or collagen fleece. The former is not biodegradable and is a surface upon which secondary bacterial infection may occur. Consequently, it has to be removed once treatment has finished. The latter has been used successfully as an adjunct to systemic antibiotics, but cannot effect a sustained release that would allow it to be used on its own, thereby avoiding systemic toxicity. This review explores the newer biodegradable carrier systems which are currently in the experimental phase of development and which may prove to be more effective in the treatment of osteomyelitis.
Smoking is known to have an adverse effect on wound healing and musculoskeletal conditions. This case-controlled study looked at whether smoking has a deleterious effect in the outcome of autologous chondrocyte implantation for the treatment of full thickness chondral defects of the knee. The mean Modified Cincinatti Knee score was statistically significantly lower in smokers (n = 48) than in non-smokers (n = 66) both before and after surgery (p <
0.05). Smokers experienced significantly less improvement in the knee score two years after surgery (p <
0.05). Graft failures were only seen in smokers (p = 0.016). There was a strong negative correlation between the number of cigarettes smoked and the outcome following surgery (Pearson’s correlation coefficient −0.65, p = 0.004). These results suggest that patients who smoke have worse pre-operative function and obtain less benefit from this procedure than non-smokers. The counselling of patients undergoing autologous chondrocyte implantation should include smoking, not only as a general cardiopulmonary risk but also because poorer results can be expected in smokers following this procedure.
Short intense electrical pulses transiently increase the permeability of the cell membrane, an effect known as electroporation. This can be combined with antiblastic drugs for ablation of tumours of the skin and subcutaneous tissue. The aim of this study was to test the efficacy of electroporation when applied to bone and to understand whether the presence of mineralised trabeculae would affect the capability of the electric field to porate the membrane of bone cells. Different levels of electrical field were applied to the femoral bone of rabbits. The field distribution and modelling were simulated by computer. Specimens of bone from treated and control rabbits were obtained for histology, histomorphometry and biomechanical testing. After seven days, the area of ablation had increased in line with the number of pulses and/or with the amplitude of the electrical field applied. The osteogenic activity in the ablated area had recovered by 30 days. Biomechanical testing showed structural integrity of the bone at both times. Electroporation using the appropriate combination of voltage and pulses induced ablation of bone cells without affecting the recovery of osteogenic activity. It can be an effective treatment in bone and when used in combination with drugs, an option for the treatment of metastases.
We implanted titanium and carbon fibre-reinforced plastic (CFRP) femoral prostheses of the same dimensions into five prosthetic femora. An abductor jig was attached and a 1 kN load applied. This was repeated with five control femora. Digital image correlation was used to give a detailed two-dimensional strain map of the medial cortex of the proximal femur. Both implants caused stress shielding around the calcar. Distally, the titanium implant showed stress shielding, whereas the CFRP prosthesis did not produce a strain pattern which was statistically different from the controls. There was a reduction in strain beyond the tip of both the implants. This investigation indicates that use of the CFRP stem should avoid stress shielding in total hip replacement.
We used interconnected porous calcium hydroxyapatite ceramic to bridge a rabbit ulnar defect. Two weeks after inducing the defect we percutaneously injected rabbit bone marrow-derived mesenchymal stromal cells labelled with ferumoxide. The contribution of an external magnetic targeting system to attract these cells into the ceramic and their effect on subsequent bone formation were evaluated. This technique significantly facilitated the infiltration of ferumoxide-labelled cells into ceramic and significantly contributed to the enhancement of bone formation even in the chronic phase. As such, it is potentially of clinical use to treat fractures, bone defects, delayed union and nonunion.
We studied the effects of coating titanium implants with teicoplanin and clindamycin in 30 New Zealand White rabbits which were randomly assigned to three groups. The intramedullary canal of the left tibia of each rabbit was inoculated with 500 colony forming units of Staphylococcus aureus. Teicoplanin-coated implants were implanted into rabbits in group 1, clindamycin-coated implants into rabbits in group 2, and uncoated implants into those in group 3. All the rabbits were killed one week later. The implants were removed and cultured together with pieces of tibial bone and wound swabs. The rate of colonisation of the organisms in the three groups was compared. Organisms were cultured from no rabbits in group 1, one in group 2 but from all in group 3. There was no significant difference between groups 1 and 2 (p = 1.000). There were significant differences between groups 1 and 3 and groups 2 and 3 (p <
0.001). Significant protection against bacterial colonisation and infection was found with teicoplanin- and clindamycin-coated implants in this experimental model.
Metastatic epidural compression of the spinal cord is a significant source of morbidity in patients with systemic cancer. With improved oncological treatment, survival in these patients is improving and metastatic cord compression is encountered increasingly often. The treatment is mostly palliative. Surgical management involves early circumferential decompression of the cord with concomitant stabilisation of the spine. Patients with radiosensitive tumours without cord compression benefit from radiotherapy. Spinal stereotactic radiosurgery and minimally invasive techniques, such as vertebroplasty and kyphoplasty, with or without radiofrequency ablation, are promising options for treatment and are beginning to be used in selected patients with spinal metastases. In this paper we review the surgical management of patients with metastatic epidural spinal cord compression.