Abduction braces are commonly prescribed following the closed reduction of a dislocated prosthetic hip joint. Their use is controversial with limited evidence to support their use. We have conducted a retrospective review of dislocations in primary total hip replacements over a nine year period and report redislocation rates in patients braced, compared to those who were not. 67 patients were identified. 69% of those patients who were braced had a subsequent dislocation. Likewise 69% of those who did not receive a brace re-dislocated. 33% of patients that were braced dislocated whilst wearing the brace. Bracing was associated with patient discomfort, sleep disturbance, skin irritation and breakdown. Small femoral head size, monoblock femoral components and poor biomechanical reconstruction was prevalent amongst dislocators. Abduction bracing following closed reduction of a total hip replacement does not prevent redislocation and may be the cause of considerable morbidity to the patient.
To determine changes in Myosin Heavy Chain (MHC) isoform, hypertrophy marker IGF-1 and atrophy markers MuRF-1 and MAFbx.
Assessments were completed at baseline (T=0), T=6 weeks (just prior to operation) and 3 months post-operatively (T=18 weeks). Assessments included isokinetic dynamometry; MRI QF CSA and American Knee Society scores. A percutaneous muscle biopsy of the vastus lateralis muscle was also performed at T=0 and T=6 under local anaesthesia.
MHC IIa mRNA expression increased by 40% whilst IIx decreased by 60% representing a shift to a less fatigable fibre type (P=0.05 and 0.028 respectively). IGF-1, MuRF-1 and MAFbx mRNA levels did not change significantly in either group.
Osteoporosis is a common skeletal disorder characterised by a reduced bone mass and a progressive microarchitectural deterioration in bone tissue leading to bone fragility and susceptibility to fracture. The Wnt/β-catenin pathway is a major signaling cascade in bone biology, playing a key role in regulating bone development and remodeling, with aberrations in signalling resulting in disturbances in bone mass. Our objectives were to assess the gene expression profile of primary human osteoblasts (HOBs) exposed to dexamethasone with a view to identifying key genes driving bone mass regulation and to assess the effects of the Wnt antagonist Dickkopf-1 (Dkk1) on the bone profile of primary human osteoblasts exposed in vitro to dexamethasone. HOBs were cultured in vitro and exposed to 10–8M dexamethasone over a time course of 4hr, 12hr and 24hr. RNA isolation, cDNA synthesis, in vitro transcription and microarray analysis were performed. Microarray data was validated by quantitative real time RT-PCR. Dkk1 expression was silenced using small interfering RNA (siRNA). Quantitative RT-PCR was performed to confirm gene knockdown. Control and Dex-treated HOBs were compared with respect to bone turnover. Markers of bone turnover analyzed included alkaline phosphatase activity, calcium deposition, osteocalcin expression, along with cell proliferation and cellular apoptosis. Global changes in HOB gene expression were elicited by dexamethasone. Development associated gene pathways were co-ordinately dysregulated with the expression profile of key genes of the Wnt Pathway significantly altered. Dkk1 expression in HOBs was increased in response to dexamethasone exposure with an associated reduction in alkaline phosphatase activity, calcium deposition and osteocalcin expression. Silencing of Dkk1 expression, as confirmed by quantitative RT-PCR, was associated with an increase in alkaline phosphatase activity and calcium deposition, along with increased cell proliferation and reduced cellular apoptosis. Dkk1 is an antagonist of Wnt/β-catenin signalling and plays a key role in regulating bone development and remodeling. Silencing the expression of Dkk1 in primary human osteoblasts has been shown to rescue the effects of dexamethasone-induced bone loss in vitro. The pharmacological targeting of the Wnt/β-catenin signaling pathway offers an exciting opportunity for the development of novel anabolic bone agents to treat osteoporosis and disorders of bone mass.
Evaluate the ability of NMES prehabilitation to improve strength and functional recovery post-TKA.
Each shear test was then repeated at four different normal loads so as to generate a family of stress-strain graphs. The Mohr-Coulomb failure envelope from which the shear strength and interlocking vales are derived was plotted for each test.
The modes of failure were aseptic loosening (4), progression of osteoarthritis (2), instability (3), infection (2), dislocated insert (1) and persistent pain after UKA (2). Tibia insert exchange was done in one patient and the rest were converted to primary Scorpio and PFC components. Three of the patients had significant defect in femoral condyle. Fourteen percent of cases required femoral stem extension or metal wedge augmentation. Nine of the 14 knees (64%) were followed up for an average of 15 months. The mean WOMAC and SF-36 scores at latest follow up were 33.33 and 63.79 respectively.
Patients with spinal cord injuries have been seen to have increased healing of attendant fractures. While the benefits are obvious, this excessive bone growth also causes unwanted side effects, such as decreased movement around joints, joint fusion and renal tract calculi. However, the cause for this phenomenon remains unclear. This paper evaluates two groups with spinal column fractures – those with neurological compromise (n=10) and those without (n=15), and compares them with a control group with isolated long bone fractures (n=12). Serum was taken from these patients at five specific time intervals post injury (1 day, 5 days, 10 days, 42 days (6 weeks) and 84 days(12 weeks)). These samples were then analysed for levels of Transforming Growth Factor-Beta (TGF-.) using the ELISA technique. This cytokine has been shown to stimulate bone formation after both topical and systemic administration. Results show TGF-.; levels of 142.79±29.51 ng/ml in the neurology group at 84 days post injury. This is higher than any of the other time points within this group (.0.009 vs. all other time points, ANOVA). Furthermore, this level is also higher than the levels recorded in the no neurology (103.51±36.81 ng/ml) and long bone (102.28±47.58 ng/ml) groups at 84 days post injury (p=0.009 and p=0.04 respectively, ANOVA). In conclusion, the results of this work, carried out for the first time in humans, offers strong evidence of the causative role of TGF-.; in the increased bone turnover and attendant complications seen in patients with acute spinal cord injuries.
Wear debris is a key factor in the pathophysiology of aseptic loosening of orthopaedic endoprostheses. Cobalt-chromium-molybdenum (Co-CrMo) alloys are used for metal-metal hip implants due to their enhanced wear resistance profiles. Whilst these alloys have widespread clinical application, little is known about their direct effect on osteoblast biology. To address this issue, in this study we have investigated particle-mediated inflammation, as a putative mechanism of aseptic loosening. The effects of Co2+ ions on the bone cellular milieu were assessed in vitro by profiling of classical inflammatory mediators. The inflammatory driver PGE2 was quantified and found to be increased, following osteoblast stimulation with metal ions, suggesting the initiation of a local inflammatory response to metal particle exposure. To determine the biological import of this molecular event, the role of metal ions in recruiting inflammatory cells by chemokine production was assessed. These data demonstrated significant induction of the chemokines, IL-8 and MCP-1 following both 12 and 24 hour exposure to 10ppm of Co2+. In this study, we demonstrate that Co2+ particles can rapidly induce chemotactic cytokines, IL-8 and MCP-1 early stress-responsive chemokines that function in activation and chemotaxis of monocytes, and PGE2, which stimulates bone resorption. We have shown that this induction occurs at a transcriptional level with significantly increased mRNA levels. These data lend further weight to the hypothesis that wear mediated osteolysis, is due, at least in part, to underlying chronic inflammation.
The purpose of this study was to review the early results of a consecutive series of patients undergoing periac-etabular osteotomy (PAO) at Cappagh National Orthopaedic Hospital. The procedure was first carried out in 1998, and a total of 85 PAOs have been performed in 79 patients. The mean follow-up was 42 months (range 6-84 months). There were 72 females and 7 males with a mean age at the time of the operation of 22.9 years (range, 14-41 years). The preoperative diagnosis was developmental hip dysplasia in 80 hips, Legg-Calve-Perthes disease in one hip, congenital coxa vara in three hips, and slipped capital femoral epiphysis in one hip. The average Merle d’Aubigne score increased from 12.4 points preoperatively to 16 points at latest followup. The lateral center edge angle of Wiberg was between – 20 and +28 before surgery and was improved from 12 to 48 (average 30 degrees) following PAO. While, the anterior center edge angle of Lequesne and de Seze was between – 22 and +35 preoperatively and was improved by an average of 28 degrees (range, 17 – 40) postoperatively. The acetabular index angle decreased from an average of 24.8 preoperatively to 8.4 postoperatively. Clinical follow-up revealed that 77% of patients had no or mild pain, 33% of patients had a limp and 64% of patients were unlimited in physical activity, representing a markedly improved clinical outcome. Four patients underwent subsequent total hip arthroplasty. The short term results in this group of patients treated with PAO show reliable radiographic correction of deformity and improved clinical scores. The study reflects the learning curve associated with performing this procedure and the results that can be expected with a smaller clinical case-load than described in previous studies. We suggest that PAO may safely be carried out at a non-super-specialized institution provided the surgeons have sufficient experience and patients are selected appropriately.
The aims of this study were to map the tibial PCL footplate using MRI in patients undergoing TKR and more importantly, to document the percentage disruption of this footplate as a result of the tibial cut.
From MRI analysis, the tibial PCL footplate had a mean surface area of 83 mm2 (range: 49 – 142), and there was a significant difference between male and female patients [Male: 104 mm2 Analysis of post-operative radiographs showed that the average tibial cut extended to 4 mm above the tip of the fibular head (range 2 mm below to 14 mm above). Over one third of patients had tibial cuts extending below the inferior most aspect of their PCL footplate (complete removal) and a further one third had cuts which extended into their PCL footplate (partial removal).
Proximal tibial cuts using conventional jigs resulted in the removal of a significant portion if not all of the PCL footplate in the majority of patients. Our findings suggest that when performing PCL retaining TKR’s, we commonly do not actually preserve the PCL.
Urinary retention following total hip and knee arthroplasty is a common problem frequently requiring catheterisation in the immediate post-operative period. The direct relationship between urinary tract instrumentation and deep sepsis in total hip replacements is well documented.
Nine (41%) patients underwent surgery and 11 (50%) required rehabilitation in the National Rehabilitation Centre, Dun Laoghaire, with an average length of inpatient stay of 9.22 months (range 5 – 14 months). Eight (36%) patients felt that their injury was preventable. Of those patients without neurology, 60% have returned to playing rugby.
Nine patients had additional acetabular bone grafting with autologous femoral head, two patients had subtrochanteric osteotomy, and another patient had an adductor tenotomy performed at the time of their surgery. Follow-up ranged from 6 to 44 (mean 19.6) months.
Nine (41%) patients underwent surgery and 11 (50%) required rehabilitation in the National Rehabilitation Centre, Dun Laoghaire, with an average length of inpatient stay of 9.22 months (range 5 – 14 months). Eight (36%) patients felt that their injury was preventable. Of those patients without neurology, 60% have returned to playing rugby.
Data recorded includes medical outcome scores (WOMAC and MOS SF-36), patient data, operative details (including type of prostheses used and operative technique employed), inpatient course, and any postoperative events. For revision procedures, additional data such as location of bony defects (Gruen zones) and acetabular bone loss (Paprosky classification) are also recorded. Follow up in a special Joint Register Clinic is at six months, two years and every five years thereafter for primary procedures. This is reduced to every two years in the case of revision procedures. To date, a pilot study involving four surgeons has prospectively captured data on 82 patients undergoing both primary and revision procedures in our unit. We aim to enrol all our patients in the register from July 2005, increasing the amount of data collected, which we hope will subsequently benefit patients undergoing hip and knee arthroplasty in the future.
To date the principal focus of the mechanism of cervical spine fracture has been directed towards head/neck circumference and vertebral geometric dimensions. However the role of other measurements, including chest circumference and neck length, in a standard cervical fracture population has not yet been studied in detail. Cervical fractures often involve flexion/extension type mechanisms of injury, with the head and cervical spine flexing/extending, using the thorax as an end point of contact. Thus, the thorax may play an important role in neck injuries.
Management of symptomatic residual acetabular dysplasia in adolescence and early adulthood remains a major therapeutic challenge. At our unit the two senior authors review all patients preoperatively and simultaneously perform each procedure. In the four years from 1998 forty-three Bernese osteotomies were performed in 40 patients with residual acetabular dysplasia. The mean average age at surgery was 21 years (range 12 – 43 years) and there were 34 female patients. The indication for surgery was symptomatic hip dysplasia (all idiopathic but for one male with a history of slipped capital femoral epiphysis) presenting with pain and restricted ambulation. 4 patients had previous surgery on the affected hip (2 Salter’s osteotomy, one Shelf procedure and one proximal femoral osteotomy). 27.5% of patients had symptomatic bilateral disease. 42% of patients had Severin class IV or V dysplasia at presentation. 100% of patients had preservation of the hip joint at last follow-up evaluation (mean 2.4 years), with excellent results in 82%, an average post-operative Harris hip score of 96, and an average d’Aubigne hip score of 16.1. The mean post-operative improvements in radiographic measures were as follows: Anterior centre edge angle +19.4°, Lateral centre angle +25.8°, Acetabular Index – 10.7°. Head to Ischial distance – 7.3mm. Surgical operative time decreased from 128 minutes to 43 minutes from the first to the most recent case. Average blood loss has reduced from 1850mls to 420mls over the four years experience. Predonation of 2 units of blood requested from all patients with baseline hemoglobin of >
12g/dl. When combined with intraopera-tive cell salvage the need for transfusion of homologous blood has been eliminated. All complications occurred in the first 9 patients: (one major – iliac vein injury requiring no further treatment; four moderate – lateral cutaneous nerve injuries; four minor – asymptomatic heterotopic ossification). Our experience confirms that the Ganz periacetabular osteotomy is an efficacious procedure for the treatment of the residually dysplastic hip, providing excellent clinical results, where early intervention is the key to improved outcome. It is a technically demanding procedure with a significant early learning curve and we believe that a two
No correlation was found between kyphotic deformity, extent of canal compromise and clinical outcome.
Percutaneous Radiofrequency Ablation (RFA) has become the method of choice in the treatment of a wide spectrum of disorders. It was introduced for the treatment of Trigeminal Neuralgia and has since been used both extensively and successfully in the treatment of this disorder. Over the past two decades it has been advocated in the treatment of hepatic metastases, lung tumours and cerebral tumours. In 1992 Rosenthal et al reported using this procedure for the treatment of Osteoid Osteomas with good outcome. Further case series have supported this modality of treatment. However, the biomechanical effects of RFA on cortical bone have not been reported to date. The study comprised of 16 large white land-raised male pigs. All were between 70–80kg in weight at the time of treatment. RFA was performed on the femur, tibia and humerus of each animal 24 hours, 1 week and 4 weeks before euthanisation. RFA was carried out via a percutaneous technique under fluoroscopic guidance. The fibula was not treated in each case and used as an intrinsic control to account for inter-group variability. The Modulus of Rigidity, Maximum Torsional Strength of all bones were determined and compared. There were three pathological fractures, all occurring in the hemerii and all occurring at 4 weeks post treatment. The Modulus of Rigidity and Maximum Torsional strength were significantly reduced at 24 hours and 1 week when compared with the control. However in the 4 weeks group the biomechanical strength of cortical bone was not significantly different and had almost returned to normal which is contradictory to the clinical setting. There was no significant difference at 24 hours and 1 week. RFA has become well established as the method of choice for the treatment of Osteoid Osteomas, however the biomechanical consequences of this procedure have not been reported to date. The torsional strength of RF ablated cortical bone is severely attenuated after 1 week, 40% reduction in torsional strength when compared with the control group. This study demonstrated that RFA of cortical bone is an effective treatment for cortical lesions however the biomechanical weakness promotes the need for weight-bearing restrictions when managing these patients postoperatively.
Between 1994 and 2002, 42 patients aged over 65 years were admitted to the spinal injuries unit with odontoid fractures. Data was retrospectively collected by analysis of the national spinal unit database, hospital inpatient enquiry (HIPE) system, chart and x-ray review. Mean age of patients was 79 years (66–88). Mean following-up with 4.4 years (1–9 yrs). Male to female ratio was 1:1.2 (M=19, F=23). Among the mechanism of injury, simple fall (low-energy) was the commonest underlying cause in 76% of the odontoid fracture, whereas 23% fractures were sustained as a result of motor vehicle accident. Fractures were classified according to Anderson and D’Alonzo method. There were 29 (69%) type 11 fractures, 13 (30%) were type 111 fractures and there was no type 1 fracture. Anterior and posterior displacements were recorded with almost equal frequency. Seven fractures displaced anteriorly and six fractures posteriorly. Primary union occurred in 59% of fractures. Forty (95.3%) fractures were treated non-operatively. Two fractures were stabilized primarily with C1/C2 posterior interspinous fusion. These fractures were odontoid type 11, anteriorly displaced. Three fractures (7.1%) failed to unite and another three fractures (7.1%) united with prolonged interval (9–11 months). Neurological compromise was mainly related to displacement of the fracture. The overall complication rate was significant (48%) with an associated in-hospital mortality of 11.1%. Loss of reduction, non-union after non operative treatment, pin site problems and complication due to associated injuries accounted primarily for this significant complication rate. Most fractures can be managed in orthosis but unstable fractures require rigid external immobilization or surgical fixation. Outcome was assessed using a cervical spine outcome questionnaire from Johns Hopkins School of Medicine. Questionnaires were sent by post to all patients identified. Non responders were subsequently contacted by phone, if possible, to complete the questionnaire. In the follow-up, additional 6(14.2%) patients were found deceased, 4 patients were unavailable for review and the remaining 69% had significant recovery. Functional outcome scores approached pre-morbid level in all patients. Outcome of these patients are related to increasing age, co-morbidity and the severity of neurological deficit.
Management of symptomatic residual acetabular dysplasia in adolescence and early adulthood remains a major therapeutic challenge. At our unit the two senior authors review all patients preoperatively and simultaneously perform each procedure. In the four years from 1998 forty-three Bernese osteotomies were performed in 40 patients with residual acetabular dysplasia. The mean average age at surgery was 21 years (range 12 – 43 years) and there were 34 female patients. The indication for surgery was symptomatic hip dysplasia (all idiopathic but for one male with a history of slipped capital femoral epiphysis) presenting with pain and restricted ambulation. 4 patients had previous surgery on the affected hip (2 Salter’s osteotomy, one Shelf procedure and one proximal femoral osteotomy). 27.5% of patients had symptomatic bilateral disease. 42% of patients had Severin class IV or V dysplasia at presentation. 100% of patients had preservation of the hip joint at last follow-up evaluation (mean 2.4 years), with excellent results in 82%, an average post-operative Harris hip score of 96, and an average d’Aubigne hip score of 16.1. The mean post-operative improvements in radiographic measures were as follows: Anterior centre edge angle +19.4°, Lateral centre angle +25.8°, Acetabular Index – 10.7°. Head to Ischial distance – 7.3mm. Surgical operative time decreased from 128 minutes to 43 minutes from the first to the most recent case. Average blood loss has reduced from 1850mls to 420mls over the four years experience. Predonation of 2 units of blood requested from all patients with baseline hemoglobin of >
12g/dl. When combined with intraoperative cell salvage the need for transfusion of homologous blood has been eliminated. All complications occurred in the first 9 patients: (one major – iliac vein injury requiring no further treatment; four moderate – lateral cutaneous nerve injuries; four minor – asymptomatic heterotopic ossification). Our experience confirms that the Ganz peri-acetabular osteotomy is an efficacious procedure for the treatment of the residually dysplastic hip, providing excellent clinical results, where early intervention is the key to improved outcome. It is a technically demanding procedure with a significant early learning curve and we believe that a two-surgeon approach is invaluable to the management of these difficult cases.
The thoracic spine has always been associated with a stability that is considerably augmented by the rib cage and associated ligaments. Fractures of the thoracic spine require great forces to be applied, causing high levels of other injuries. In addition, the narrow spinal canal dimensions result in high levels of neurological compromise when fractures occur. Between February 2nd 1995 and March 21st 2001, 1249 patients were admitted to our spinal tertiary referral unit. Of these, 77 had suffered fractures to some part of their upper thoracic spine (T1–T6), of which, 32 required surgical procedures. Using patient case notes, we retrospectively studied this series. Twenty-six of the 32 patients were male, with an average age of the group of 24.4 +/− 11.3 years and an average impatient stay of 17.5 +/− 10.5 days. 29 patients suffered fractures at more than one level and 23 patients suffered complete neurological compromise. Only 2 patients were neurologically intact. 90.7% sustained their injuries in road traffic accidents, with 53.9% of the male group being involved in motorcycle accidents. Multiple imaging (in addition to plain film radiography) was required in 30 cases with 20 patients suffering injuries apart from their spinal fracture. Of these, 15 had associated chest injuries. Cardiothoracic surgical consultants were required in 56.3% of cases, and from the general surgeons in 37.5% of patients. 59.4% of patients required intensive care unit therapy, with another 4 patients going to the high dependency unit. Fractures to the upper thoracic spine are injuries with devastating consequences, both due to high levels of neurological compromise and concomitant injuries. This series would suggest that patients suffering from these injuries are best treated in a multi-disciplinary approach within a general setting, rather that in a specialist orthopaedic unit, where other medical and surgical services may not be readily available.
The Mater Hospital is Ireland’s primary referral centre for spinal injuries receiving 80–90% of all spinal cases annually. In today’s society the number of people competing at more competitive and professional levels is also increasing. Over the years, a lot of work has gone into safety precautions in sport. However despite those improvements our impression was that the incidence of both minor and serious sporting injuries is increasing. The purpose of this study was to determine the incidence, pattern and mechanism of sports-related spinal injuries in Ireland over the last decade. Data was collected by performing an audit of the National Spinal Injuries Database from 1994–2001. This database is a prospective computerized database. Data entered relates to the initial presentation, mechanism, level of injury and their acute in-hospital management. On average 200–220 patients are admitted annually to the National Injuries Spinal Unit. 173 of these were related to sport, which represented 13% of total spinal injuries. 80% are male under 40 years. 29% sustained neurological deficit. The sports responsible for most spinal injuries in Ireland were equestrian (43.8%), followed by rugby (16.4%), diving (15%), GAA (13.6%) and skiing (3%). Rugby injuries were most likely to cause neurological damage. Equestrian accidents commonly caused thoracolumbar fractures while injuries sustained in diving, rugby and GAA were mostly to the cervical spine. Sport is an important cause of spinal injuries in Ire-land. Coaches and team doctors must be educated about safe practices and emergency management of these terrible injuries and for those unfortunately affected in the prime of their lives adequate rehabilitation resources need to be implemented so as to lessen their economic burden.
Data = mean ± standard deviation. Statistical analysis was by students t test. A significant result between control and stimulated groups is indicated by: * p=0.024m, † p=0.0007 or ‡ p=0.012. Methylprednisolone (2mg/ml) caused a significant (p=0.044) 30-fold reduction in IL-6 production and a significant (p=0.00004) 500-fold reduction in IL-8 levels as compared with nucleus pulposus cultured with 5 μg/ml LPS alone for 24 hours. Addition of 500 μM indomethacin significantly (p=0.04) decreased IL-6 production by a factor of 120 and IL-8 levels by a factor of 50 (p=0.00004). Necrotic cell death, as measured by lactate dehydrogenase (LDH) concentration, was not significant in any of the experiments.
In summary, this study suggests that patients with symptomatic knee arthritis are likely to have meniscal derangement and medial collateral oedema. A greater understanding of the origin of pain in the degenerate knee may assist in the choice of management options for these patients.
Standard protocol following total hip arthroplasty dictates that the hip is kept in a position of abduction until soft tissue healing is sufficient to provide stability. This is maintained by use of an abduction pillow while in bed, meaning that the patient must sleep on their back. Many patients find this position uncomfortable and have significant difficulty in sleeping.
The thoracic spine has always been associated with a stability that is considerably augmented by the rib cage and associated ligaments. Fractures of the thoracic spine require great forces to be applied, causing high levels of other injuries. In addition, the narrow spinal canal dimensions result in high levels of neurological compromise when fractures occur. Between 2 February 1995 and 21 March 2001, 1249 patients were admitted to our spinal tertiary referral unit. Of these, 77 had suffered fractures to some part of their upper thoracic spine (T1-T6), of which 32 required surgical procedures. Using patient case notes, we retrospectively studied this series. 26 of the 32 patients were male, with an average age of the group of 24.4 ± 11.3 years and an average inpatient stay of 17.5 ± 10.5 days. 29 patients suffered fractures at more than one level and 23 patients suffered complete neurological compromise. Only 2 patients were neurologically intact. 90.7% sustained their injuries in road traffic accidents, with 53.9% of the male group being involved in motorcycle accidents. Multiple imaging (in addition to plain film radiography) was required in 30 cases with 20 patients suffering injuries apart from their spinal fracture. Of these, 15 had associated chest injuries. Cardiothoracic surgical consultations were required in 56.3% of cases, and from the general surgeons in 37.5% of patients. 59.4% of patients required intensive care unit therapy, with another 4 patients going to the high dependency unit. Fractures to the upper thoracic spine are injuries with devastating consequences, both due to high levels of neurological compromise and concomitant injuries. This series would suggest that patients suffering from these injuries are best treated in a multi-disciplinary approach within a general setting, rather than in a specialist orthopaedic unit, where other medical and surgical services may not be readily available.
Degenerate disc disease is a major cause of low back pain, yet its aetiology is still poorly understood. The intervertebral disc is the largest avascular structure in the body. Cells of the nucleus pulposus, therefore, rely on diffusion of oxygen &
nutrients down concentration gradients from peripheral vessels in the cartilage end-plates. Thus, there is a low oxygen tension and cellular respiration is largely anaerobic. The purpose of this study was to examine the effects of inflammation, hypoxia and acidosis on degeneration and pro-inflammatory mediator production in virgin porcine nucleus pulposus cultures. Intervertebral discs were harvested from normal 6-month old agricultural pigs slaughtered for other purposes. Nucleus pulposus was contained within the annulus until further dissection under sterile conditions in the laboratory was performed. Nucleus pulposus was harvested, diced and divided into 200mg samples. Samples were incubated under optimal conditions. Discs were cultured in 5μg/ml E. coli lipopolysaccharide, in a hypoxic environment or at low pH. IL-6, IL-8 and LDH assays were performed by ELISA, in accordance with manufacturer’s instructions. Time and dose-response curves were generated for each experiment (results not shown). Results at 72 hours incubation are tabulated below: These results confirm that nucleus pulposus is a biochemically active tissue capable of producing pro-inflammatory mediators in response to environmental stresses. IL-6 and IL-8 are both involved in the inflammatory cascade, causing chemotaxis of neutrophils and macrophages to the area. IL-8 itself causes hyperalgesia. Acidotic and inflammatory conditions, but not hypoxia, stimulated cytokine release. This may indicate a protective reduction in cellular activity in reduced oxygen environments. Necrosis, as measured by LDH production, was negligible.
Aseptic loosening is currently the leading cause of failure of total hip arthroplasty. The aetiology of periprosthetic bone resorption is currently under intense investigation. Wear particles are produced from the articulating surface of the femoral and acetabular components. These particles gain access to the bone-cement interface where they are phagocytosed by macrophages. Particle stimulated macrophages differentiate into bone resorping osteoclasts. This leads to periprosthetic bone resorption and subsequent implant loosening. Nuclear factor kappa B (NFκB) is a transcription factor known to be activated by pathogenic stimuli in a variety of cells. The activation of NFkB would appear to be the primary event in the activation of particle stimulated macrophages in the periprosthetic membrane. NFκB subsequently causes a cascade of events leading to the release of bone resorbing cytokines, namely interleukin-6 (IL-6) and tumour necrosis factor α (TNFα). The aim of our study was to ascertain if bone resorption could be prevented in vitro by the addition of PDTC, an NFkB inhibitor to particle stimulated macrophages. Human monocytes were isolated and cultured from healthy volunteers. The monocyte/macrophage cell line was differentiated into osteoclasts by the addition of alumina particles and allowed to adhere onto bone slices. The NFkB inhibitor, PDTC, has added to the cultured osteoclasts. Bone resorption was analysed by counting the number of resorption pits in each bone slice. The addition of PDTC to stimulated macrophages reduced the number of resorption pits by greater than 40% compared to control. This is a unique and promising finding that may offer a future therapeutic strategy for the prevention of periprosthetic bone resorption and therefore aseptic loosening in total hip arthoplasty.
The management of type two odontoid peg fractures remains controversial. The policy in our unit is to initially manage all of these injuries non-operatively. Patients with displaced fractures (0.2mm translation, >
15° angulation) are placed in halo vests followed by fracture reduction under radiological control. Undisplaced or minimally displaced fractures are treated in either custom-made minerva orthoses or halo vests. We report the results of 42 consecutive cases of type two odontoid peg fractures. There were 24 males and 18 females with a mean age of 53 (range 18–89) years. Twenty-one (50%) of patients were >
65 years of age. In 29 cases the fracture was undisplaced or minimally displaced and in the remaining 13 cases it was displaced (>
2mm translation, >
15° angulation) either posteriorly (extension-type)(6) or anteriorly (flexion type) (7). All displaced cases were treated in halo vests while the remainder were treated in minervas (14) or halo vests (15). Loss of reduction occurred in nine cases necessitating adjustment in five and C1/2 posterior fusion in four. Of these cases five were displaced extension type-fractures, two required fusion. Pin site infection necessitated early removal of halo vest and conversion to minerva in three cases. In all of these cases fracture union was achieved. Overall, union was achieved in 37 patients giving a non-union rate of 12%. The mean age of the five non-unions was 42 years with only one patient over 65 years of age. Four of these patients had C1/2 posterior fusions and the remaining patient refused surgery. Of the 29 patients with displaced or minimally displaced fractures five (17%) required surgery for either non-union (3) or displacement (2), whereas three (23%) of the displaced group required surgery for non-union (1) or displacement (2). All of these were extension type fractures. We conclude that a policy of non-operative management of these fractures resulted in union in a high proportion of patients of all age groups except for those with extension type fractures. This fracture pattern may warrant primary surgical intervention.
Aseptic loosening has become the single most important long-term complication of total joint replacements. The pathophysiology of this loosening is multifactorial in origin ranging from mechanical wear, poor surgical technique, thermal damage and the inflammatory response to particulate wear debris. Cytokines are released in response to macrophage activation by particulate wear debris (PWD), the resultant inflammatory cascade stimulates osteoclastic resorption of bone. The failure of remodelling and repair mechanisms may be as a result of Osteonecrosis from cement (PMMA).
This study examines patient characteristics, indications for conversion, surgical and anaesthetic technique, peri-operative management and complications of surgery in this small and challenging group of patients. In the six years from 1994 to 1999, 33 conversion arthroplasties were performed for failed femoral hemiarthroplasty. The average age at conversion surgery was 75.5 years (range 65–90). The female to male ratio was 6:1. Primary hemiarthroplasties comprised 24 Austin-Moore, 6 Thompson &
3 Bipolar prostheses. The average interval from primary to conversion surgery was 50 months (6 months to 17 years). The average age at primary surgery was 71.2 years (62–88) – AMP:71.4 years, Thompson’s: 74.2 years, Bipolar: 63.5 years. All hemiarthroplasties were performed for fractured femoral necks. 62% of patients came from the Eastern Health Board area, while 38% were tertiary are referrals from other Health Boards. The average length of stay was 17.5 days (3–24). Indications for conversion included gross loosening/acetabular erosion in 9 cases, suspected infection in 4 cases and abscess/septicaemia in 1 case. All but 3 patients had significant pain (night pain etc.) and/or severely impaired mobility. We also looked at anaesthetic and analgesic practice, surgical technique and prostheses used. Post-operatively, mean total blood loss was 1430 ml (420–2280) with an average of 1.4 units of blood transfused (0–5). Intraoperative complications included acetabular &
femoral perforation, periprosthetic fracture and cement reactions. Complications post-op (in hospital) included cardiac arrhythmia’s, cerebrovascular accidents, pulmonary embolus, myocardial infarct, respiratory &
urinary tract infections, constipation, nausea &
vomiting. The elderly nature of these patients and the physiological stress of what is major surgery allied with multiple co-morbidities make their care especially challenging. A conversion arthroplasty is a procedure with a significant risk of considerable morbidity. Primary total hip replacement or bipolar hemiarthroplasty are options which, therefore, should be seriously considered in the case of fractured femoral necks to minimise the need for further surgery in the future, with all its attendant risks.