Background

Supination-external rotation (SER) injuries make up 80% of all ankle fractures. SER stage 2 injuries (AITFL and Weber B) are considered stable. SER stage 3 injury includes disruption of the posterior malleolus (or PITFL). In SER stage 4 there is either medial malleolus fracture or deltoid injury too. SER 4 injuries have been considered unstable, requiring surgery. The deltoid ligament is a key component of ankle stability, but clinical tests to assess deltoid injury have low specificity. This study specifically investigates the role of the components of the deep deltoid ligament in SER ankle fractures.

Osteoporosis is a disease when bone mass and tissue is lost, with a consequent increase in bone fragility and increase susceptibility to develop fracture. The osteoporosis prevalence increases markedly with age, from 2% at 50 years to more than 25% at 80 years¹ in women. The vast majority of distal radius fractures (DRFs) can be considered fragility fractures. The DRF is usually the first medical presentation of these fractures. With an aging population, all fracture clinics should have embedded screening for bone health and falls risk. DRF is the commonest type of fracture in perimenopausal women and is associated with an increased risk of later non-wrist fracture of up to one in five in the subsequent decade².

According to the national guidelines in managing the fragility fractures of distal radius with regards the bone health review, we, as orthopedic surgeons, are responsible to detect the risky patients, refer them to the responsible team to perform the required investigations and offer the treatment.

We reviewed our local database (E-trauma) all cases of fracture distal radius retrospectively during the period from 01/08/2019 to 29/09/2019. We included total of 45 patients who have been managed conservatively and followed up in fracture clinic. Our inclusion criteria was: women aged 65 years and over, men aged 75 years and over with risk factors, patients who are more than 50 years old and sustained low energy trauma whatever the sex is or any patient who has major risk factor (current or frequent recent use of oral or systemic glucocorticoids, untreated premature menopause or previous fragility fracture).

We found that 96% of patients were 50 years old or more and 84% of the patients were females. 71% of patients were not referred to Osteoporosis clinic and 11% were already under the orthogeriatric care and 18% only were referred. Out of the 8 referred patients, 3 were referred on 1st appointment, 1 on the 3rd appointment, 1 on discharge from fracture clinic to GP again and 3 were without clear documentation of the time of referral.

We concluded that we as trust are not compliant to the national guidelines with regards the osteoporosis review for the DRF as one of the first common presentations of fragility fractures. We also found that the reason for that is that there is no definitive clear pathway for the referral in our local guidelines.

We recommended that the Osteoporosis clinic referral form needs to be available in the fracture clinic in an accessible place and needs to be filled by the doctor reviewing the patient in the fracture clinic in the 1st appointment. A liaison nurse also needs to ensure these forms have been filled and sent to the orthogeriatric team. Alternatively, we added a portal on our online database (e-trauma), therefore the patient who fulfils the criteria for bone health review should be referred to the orthogeriatric team to review.

Congenital talipes equinovarus (CTEV), also known as club foot or talipes is a common congenital disorder. Parents are using the Internet more and more as a source of information about health care. Unfortunately, the quality of health care information on the Internet varies. This study looked at information available to parents using two instruments for judging the equality of information on the internet. The top five search engines were searched on Google. Three of these were also included in the top 50 sites in Ireland so these 3 sites were used. The phrases CTEV and club foot were searched from all 3 platforms. Websites were then scrutinized using the HON code and the DISCERN tool. 54 organic sites were found for the 3 search engines using the key word club foot. For the key word CTEV 55 matches were returned for the three search engines. 4 websites displayed the HON code. Using the discern tool CTEV websites had a mean score of 60 with a standard deviation of 17. While club foot had a mean score of 56.8 with a standard deviation of 13. Max score 80. Large volumes of information are available to parents on the Internet. Often parents find comfort in sharing experiences and feel empowered by learning about their children's illnesses. However, information provided on the interned can also be ambiguous and disingenuous. Practitioners should be aware of a number of key websites that parents can be directed towards.

Innominate Osteotomy first described by Salter is one of the commonest procedures performed for treatment of Developmental Dysplasia of the Hip (DDH) in children. We recently described a less invasive technique for Innominate Osteotomy, which significantly reduces the operation time without compromising outcome (J Pediatr Orthop B. 2010 Jul;19(4):318–22). As part of the evolution of this procedure we now routinely use bioabsorbable pins (INION OTPS PIN, made from co-polymers of L-lactic acid, D-lactic acid and trimethylene carbonate) instead of K-wires to secure the graft.

We prospectively followed-up 120 consecutive cases done using bioabsorbale pins over a 2 year period. The surgical technique was as described in our less invasive innominate osteotomy paper. Average age at surgery was 24 months (18–52) with mean follow-up period of 15 months (6–24 months). The mean preoperative acetabular index was 36.2^o. Our results show a mean acetabular index of 18.7^o (P< 0.0001) at latest follow-up with no loss of correction. We recorded three superficial wound infections (one MRSA), all resolved uneventfully. There was no foreign body reaction.

The use of bioabsorbable pins eliminates the need for a second anaesthetic to remove the pins with significant cost benefit without compromising outcome.

Introduction

Trauma is the leading cause of death and disability in children. Pelvic fractures although rare, with a reported incidence of one per 100,000 children per year are 2^nd only to skull fractures with respect to morbidity. The objectives of this study were to improve understanding of paediatric pelvic fractures through a concise review of all aspects of these fractures and associated injuries. Understanding the patterns in which paediatric pelvic fractures and their associated injuries occur and the outcome of treatment is vital to the establishment of effective preventative, diagnostic and therapeutic interventions.

Hypothesis

Athletes significantly alter their lumbar spinal motion when performing squat lifting at heavy weights. This altered motion effects a change in pressure in the posterior annulus of lumbar discs.

Purpose: Biomaterial-related infections continue to hamper the success of reconstructive and arthroplasty procedures in orthopaedic surgery. Staphylococci are the most common etiologic agents, with biofilm formation representing a major virulence factor. Environmental stress factors and sub-inhibitory concentration of some antibiotics have been identified to trigger staphylococcal biofilm formation through increased icaADBC expression. In staphylococci, production of polysaccharide intercellular adhesin (PIA) by the enzyme products of the icaADBC operon is the best understood mechanism of biofilm development, making the ica genes a potential target for biofilm inhibitors. Aims of the current study were

Determine the minimum inhibitory concentration (MIC) of Povidone-iodine.

Method: MIC of povidone – iodine for both reference strains and strains isolated from infected orthopaedic implants was determined. Biofilm assay was performed at different Povidone-iodine concentrations using 96-well polystyrene plates. Total RNA for cDNA synthesis was isolated from bacteria at different twofold dilutions of Povidone-iodine concentrations. Real time polymerase chain reaction was used to quantify effects of Povidone-iodine on gene expression pattern of the icaADBC operon using the constitutively expressed gyrB gene as internal control

Results: The MIC of povidone-iodine was 1.4% for all bacterial strains. Clinical in-use doses of povidone-iodine prevented biofilm formation.

A step-wise reduction of biofilm was observed at increasing sub-inhibitory doses of povidone-iodine (p< 0.0001).

IcaA expression correlated with biofilm formation in staphylococcal organisms. Decrease in icaA expression was strongly associated with an increase in expression in the biofilm repressor gene, icaR.

The repressive effect of povidone-iodine on biofilm formation by Staphylococcal bacteria is by a separate mechanism from its bacteriostatic mechanism of action.

Conclusion: This study shows that icaR is a potential therapeutic target through which the ability of Staphylococcal bacterial to form biofilm may be reduced. These data reveal an additional therapeutic benefit of povidone-iodine and suggest that studies to evaluate the suitability of povidone-iodine as biomaterial coating agent to reduce device-related infection rates are merited.

Background: The success of the increasing number of arthroplasty, spinal instrumentation and other implanted orthopaedic devices is hampered by device-related infections. More than half of these infections are caused by staphylococcal biofilm mediated antibiotic resistance. The hope of preventing prosthetic joint infection by antibiotic loaded cement is threatened by emerging resistant organisms. No bacterial resistance to betadine has been reported.

Current intervention strategy is focussed on prevention of initial device colonisation and inhibition of genes encoding biofilm formation.

Aim:

Determine the minimum inhibitory concentration (MIC) of betadine.

Methods: MIC of betadine for both reference strains and strains isolated from infected orthopaedic implants was determined. Biofilm assay was performed at different betadine concentrations using 96-well polystyrene plates.

Total RNA for cDNA synthesis was isolated from bacterial at different twofold dilutions of betadine concentrations.

Real time polymerase chain reaction was used to quantify effects of betadine on gene expression pattern of the icaADBC operon using the constitutively expressed gyrB gene as internal control.

Bacterial was cultivated on polystyrene plates coated with different sub-inhibitory and clinical in-use doses of betadine to assess surface adherence.

Results: The MIC of betadine was 1.4% for all bacterial strains. Clinical in-use doses of betadine prevented biofilm formation.

A step-wise reduction of biofilm was observed at increasing sub-inhibitory doses of betadine (p< 0.0001).

IcaA expression correlated with biofilm formation in staphylococcal organisms. Decrease in icaA expression was strongly associated with an increase in expression in the biofilm repressor gene, icaR.

The repressive effect of betadine on biofilm formation by Staphylococcal bacteria is by a separate mechanism from its bacteriostatic mechanism of action.

Conclusion: This study shows that icaR is a potential therapeutic target through which the ability of Staphylococcal bacterial to form biofilm may be reduced. Sub-inhibitory dose of betadine inhibited biofilm formation.

Prevention of bacterial surface attachment as demonstrated by this study is suggestive that these compounds could be developed as a surface coating agents for orthopaedic implants.

Hypothesis: Athletes significantly alter their lumbar spinal motion when performing squat lifting at heavy weights. This altered motion effects a change in pressure in the posterior annulus of lumbar discs.

Study Design:

3-D motion analysis of lumbar spinal motion in athletes, during squat weight lifting.

Methods: 48 athletes performed 6 lifts at 40% maximum, 4 lifts at 60% max and 2 lifts at 80% max. 3-D motion analysis system, measured lumbar spine motion. Exercise performed as a ‘free’ squat and repeated with a weight lifting support belt.

4 cadaveric sheep spinal motion segments mounted in purpose built jig, replicating angulation seen in the in vivo motion study. These samples were then fixed to a tension/compression loading frame, replicating the forces seen in the in vivo study. Pressure measurement was achieved using a Flexiforce single element force sensor strip, positioned at the posterior annulus.

Posterior annulus pressure was measured during axial compression and on compression with the specimen fixed at 3° of extension.

Results:

Significant decrease (p< 0.05) in flexion in all groups when lifting at 40% max was compared with lifting at 60% and 80% of max. Flexion from calibrated zero point ranged from 24.7° (40% group), to 6.8° (80% group). A progressively significant increase (p< 0.05) seen in extension in groups studied when lifting at 40% max was compared with lifting at 60% and 80% max lift. Extension from a calibrated zero point ranged from − 1.5° (40% group), to − 20.3° (80% group). No statistically significant difference found between motion seen when performing the exercise as a ‘free’ squat or when lifting using a support belt in any group studied.

Comparing axially loaded specimens with specimens loaded in extension, there was an average increase in pressure of 36.4% in the posterior annulus, when the spine was loaded in 3° of extension at a pressure equivalent to the 80% lift in the in vivo motion study, in comparison to axial loading.

Conclusions: Squat weight lifting at heavier weights, causes athletes to lift at a progressively greater degree of extension. The use of a weight lifting support belt does not significantly alter spinal motion during lifting. The increased extension at heavier weights results in a stress concentration in the posterior annulus of lumbar discs.

Introduction: Duchenne’s Muscular Dystrophy (DMD) is a progresssive sex linked recessive disorder predominantly involving skeletal muscle. Scoliosis is almost universal in patients with DMD. Surgical stabilisation carries significant risks and complications with per-operative mortality of < 6%. Cardiopulmonary complications along with severe intraoperative blood loss requiring massive nlood transfusion are the major cause of morbidity.

Aim: To evaluate the efficacy of single rod fusion technique in reducing the peroperative and post operative complications especially blood loss, duration of surgery and progression of curve.

Materials and Methods: Retrospective review- 32 patients with scoliosis secondary to DMD with an average age of 14 years (range, 11–18) underwent either single rod fusion technique (19 patients) using Isola rod system or Hartshill rectangle/double rod fusion technique (13 patients). Blood loss was measured directly from the peroperative suction and postoperative drainage, indirectly by weighing swabs. Vapour free hypotensive anaesthesia was used in all cases. Progression of curve was followed up in the outpatients.

Results: The mean operative time was 130 minutes (range, 80–180) for the single rod fusion technique in comparison to 250 minutes (range, 170–300) for the Hartshill/Double rod technique. The average blood loss for the single rod fusion technique was reduced, 2.2 L (range 0.4–4) versus 3.1L (0.8–4). The mean follow up was 35 months (range, 5–72). The inpatient stay was 12 days (range, 6–23). Seven patients developed complications: 3 ileus, 2 respiratory tract infections, one patient had loosening and migration of the rod, which required revision under LA, and one patient developed a superficial wound infection, which resolved with intravenous antibiotics.

Conclusion: In our experience, single rod stabilisation is a safe and quick method of correcting the DMD scoliotic spine, with less blood loss and complications compared to traditional methods.

The cervical spine exhibits the greatest range of motion amongst the spinal segments due to its tri-planar components of movement. As a result, measurement of movements has proved difficult. A variety of methods have been used in an attempt to measure these movements but none have provided satisfactory triplanar data.

This paper uses the Zebris ultrasonic 3-D motion analysis system to measure flexion, extension, range of lateral bending and range of axial rotation in five similar male and five similar female subjects with no history of neck injuries. The subjects were tested unrestrained and in soft and hard collars, as well as in Philadelphia, Miami J and Minerva orthoses.

Results show that the Minerva is the most stable construct for restriction of movement in all planes in both groups (p< 0.001 vs. all groups (p=0.01 vs. Philadelphia in female extension), ANOVA). In the male group, the standard hard collar provides the second best resistance to flexion, lateral bending and axial rotation. The female group showed no one orthosis in second place overall. Looking at these results allows ranking of the measured orthoses in order of their three-dimensional stability. Furthermore, they validate the Zebris as a reliable and safe method of measurement of the complex movements of the cervical spine with low intersubject variability.

In conclusion, this paper, for the first time presents reproducible data incorporating the composite triplanar movements of the cervical spine thus allowing comparative analysis of the three-dimensional construct stability of the studied orthoses. In addition, these results validate the use of the Zebris system for measurement of cervical spine motion.

Aims: A retrospective review of all periacetabular osteotomies (PAO) performed at a general elective orthopaedic Hospital over a 7-year period. To assess the clinical, functional and radiographic outcome associated with PAO when introduced as a new procedure to a non-super-specialised regional centre.

Methods: A retrospective review of 85 PAOs performed on 79 patients at Cappagh Hospital between 1/4/1998 and 1/4/2005. The medical records and radiographic images of all patients were reviewed. Clinical follow-up evaluations were also performed.

Results: 85 PAOs were performed on 79 patients. Mean age at time of surgery was 22.9 years (range, 14–41 years) with an increased preponderance of females (F:M=10:1) and right sided hip involvement (R:L=1.1:1). The mean Merle D’Aubigne and Postel hip score increased from 12.4 (range 9–14) preoperatively to 16 (range 11–18) postoperatively (P< 0.0001). The average lateral center edge angle increased from 5° preoperatively to 26° postoperatively (P< 0.0001). The anterior center edge angle averaged 6.6° preoperatively and improved to 34.4° postoperatively (P < 0.0001). The acetabular index angle decreased from an average of 24.8° preoperatively to 8.4° postoperatively (P< 0.0001). At clinical follow-up, 77% of patients had no/mild pain, 30% of patients had a limp and 64% of patients were unlimited in physical activity.

Conclusions: The short term results in this group of patients treated with PAO show reliable radiographic correction of deformity and improved clinical scores. 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 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.

Many pedicle screw instrumentation systems are currently available to the spine surgeon. Each system has its unique characteristics. It is important for the surgeon to understand the differences in these pedicle screw systems¹

Following the introduction of a new spinal instrumentation set to our clinical practice we encountered two cases of pedicle screw breakage. We thus decided to investigate the mechanism of this screw failure (screw A) in these particular cases and to compare the biomechanical properties, through independent analysis, of a variety of pedicle screws from different manufacturers.

Samples of the broken pedicle screws were retrieved at surgery. Surface analysis of the fracture area using the electron microscope, demonstrated features consistent with fatigue fracture.

Pedicle screws of comparable size from a variety of manufacturers were gathered for independent analysis. Shadowgraph analysis was performed of each screw allowing multiple measurements to be taken of the screw’s geometry. Using this data stress concentration factors were determined demonstrating screw A to have larger values than all the other screws ranging from 2 – 3.6 times the nominal stress. The smaller teeth of screw A, spaced further apart than in the other screws, means that the large proportion of the load which would be carried by the threads is distributed over a smaller area resulting in higher stresses in the threads. The sharp corner at the root of the thread, acting as a stress concentrator, would become the focal point of these high stresses, and magnify them by 2 to 3.6 times.

These increased stresses most likely account for an increased susceptibility to fatigue fracture seen in screw A.

In conclusion it is important to be careful with the introduction and use of new pedicle screw materials and designs, that all the standard biomechanical testing has been performed to a satisfactory standard.

Knowing the physical characteristics of the available pedicle screw instrumentation systems may allow the choice of pedicle screw best suited for a given clinical situation.

Slipped upper femoral epiphysis (SUFE) is a condition, which affects the immature hip joint. Many theories have been postulated as to its underlying aetiology however; its exact cause is, as yet unknown. The final common pathway appears to be failure of the of the growth plate to resist shearing forces, giving rise to displacement of the femoral head. We hypothesized that the lubricating ability of the synovial fluid in hip joints of children with SUFE was defective, thereby allowing increasing shear forces on the physis to occur, so that when the joint is loaded it will fail at its weakest point, namely the capital epiphysis.

Aim: The aim of this study was to establish a biomechanical porcine cadaveric model to study SUFE and use this model to determine how defective joint lubrication may increase the probability of SUFE.

Methods: Using immature porcine femurs and a custom-made rig, a torsional load was applied about an axis perpendicular to the growth plate in order to cause the femur to fail along the growth plate. The Hounsefield testing machine applied a tensile load and recorded the associated elongation. From these figures the torque applied to the femoral head and the associated angular rotation could be computed. Using Weibel analysis we were able to determine the probability of SUFE occurring for a range of synovial fluid coefficients of friction, a range of joint reaction forces and neck-shaft angles.

Results: We found that it is possible to induce a SUFE in an immature porcine loaded hip joint and that there was an increased probability of slip with increased coefficient of friction of synovial fluid, increased percentage body weight and increased neck-shaft angle.

Conclusion: Defective lubrication may be a key underlying aetiological factor responsible for SUFE.

Introduction: Total hip arthroplasty for osteoarthritis secondary to developmental dysplasia of the hip (DDH) is technically difficult due to the abnormal anatomy involved. The use of a modular hip replacement system is advantageous in that its versatility allows for intra-operative adjustment to accommodate for final acetabular position and version.

Aim: The aim of this study was to assess our early results with the S-ROM hip (DePuy), a cementless modular femoral implant.

Methods and materials: We performed 22 total hip replacements on 20 patients with DDH over a three and a half year period. Nineteen patients were female and one was male. Ages ranged from 30 to 59 years (average 38.3 years). Ten patients had had previous osteotomies performed, including two of whom had Ganz periace-tabular osteotomies performed in our centre.

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.

Results: Harris hip scores improved from an average of 42 points pre-operatively to 90 points post-operatively. No radiographic evidence of osteolysis was seen around the femoral implant. Two patients required revision of their acetabular components. Both had satisfactory outcomes.

Conclusion: Our early results with the S-ROM femoral prosthesis correlate well with those from other studies involving arthroplasty for DDH. There were no complications related to the use of uncemented prostheses. Modularity makes this implant extremely versatile and easy to use in this complex patient population.

Purpose: The use of a bioabsorbable suture anchor across a joint as a means of internal stabilization has not previously been described. This study assesses the iatrogenic damage caused by such a procedure in the normal immature porcine hip.

Materials and Methods: Six twelve week old pigs underwent unilateral transarticular suture anchorage of the hip using a Panalok® RC Quick Anchor® Plus with Panacryl® suture. (Mitek® Products Johnson and Johnson). Anteroposterior pelvic radiographs were taken pre-operatively and six weeks post-operatively. Acetabular index, diameter of the femoral head ossific nucleus of both hips on both occasions were measured and compared. Pigs were sacrificed six weeks post-operatively. Specimens were analysed macroscopically for femoral head diameter, acetabular dimensions, and presence of gross chondrolysis. Histological analysis was performed to assess the presence of articular chondrolysis, and proximal femoral physeal arrest.

Results: In four out of six hips the rate of change of the acetabular index slowed as compared to the unoperated side though none worsened. The diameter of the femoral ossific nucleus on the operated side continued to increase in size at a similar rate as the unoperated side, despite the surgical procedure according to radiographic comparison. Similar findings were made in the macroscopic analysis of the hip geometry. Gross and histological analysis of the articular cartilage show only local areas of chondrolysis related to the drill holes, and in one hip where a second hole was drilled, cartilage regeneration was noted. Metaphyseal growth at the proximal femoral physis was unaffected by the procedure.

Conclusions: The use of a trans-articular suture anchor across the hip appears to cause marginal retardation of acetabular development in the normal hip. The procedure does not appear to affect proximal femoral physeal or epiphyseal growth and the presence of a bioabsorbable suture within the joint did not result in chondrolysis.

Introduction: Staphylococcal bacteria, especially the coagulase negative Staphylococci, are responsible for the majority of orthopaedic device related infection. These infections are sub acute, and may not present for months or years following surgery. The virulence of these bacteria is related to their ability to form biofilm, a protective slime which allows them to survive the effects of the host immune system and antimicrobial therapy. Treatment of biofilm based infection almost always necessitates removal of the implant.

Recent work has identified environmental stimuli which induce biofilm formation in Staphylococci. These include stressors such as high temperature, high osmolarity, anaerobiosis, nutrient depletion, salt, ethanol and subinhibitory concentrations of certain antimicrobial drugs. Given the ability of these bacteria to survive the “respiratory burst” from the cells of the mononuclear-macrophage system, we hypothesised that oxidative stress may be one such promoter of biofilm formation by Staphylococci.

Methods and Materials: Staphylococcus epidermidis CSF41498 and Staphylococcus aureus RN422O were selected for study as these are known biofilm forming organisms. Hydrogen peroxide (H₂O₂) was used as an oxidizing agent.

Bacteria were incubated for 24 hours at 37°C in Brain-Heart Infusion (BHI, Oxoid) containing progressively weaker concentrations of H₂O₂ to determine a Minimal Inhibitory Concentration (M.I.C.) for the representative strains. Bacterial viability was assessed by measuring the optical density of the incubated culture using a cell density meter (Ultraspec 10, Amersham Biosciences).

The bacteria were then grown as a biofilm on a 96 well microtitre plate (Nunc) in the presence of subinhibitory concentrations of H₂O₂, using pure BHI as a control. Semiquantative determination of biofilm formation was performed by washing the plates, staining the adherent cells with crystal violet, and measuring the light absorbance of the adherent stained cells at 492 nm using a Multiskan plate reader (Flow Laboratories).

Results: The M.I.C. of H₂O₂ was 18 mM for both Staphylococcus epidermidis CSF41498 and Staphylococcus aureus RN422O. Concentrations of H₂O₂ of 16 mM and below had no normal bacterial growth and replication.

There was no difference in biofilm formation by Staphylococcus epidermidis csf41498 in the presence of 15 mM H₂O₂ when compared to that of the control. However, H₂O₂ had a significant inhibitory effect on biofilm formation by Staphylococcus aureus RN422O, even at a concentration well below the M.I.C.

Conclusion: We conclude that oxidative stress may have an antibiofilm action on certain Staphylococcal species, which is independent from its bactericidal effect, and which is manifest at a concentration below the M.I.C. for that species.

Introduction: The use of a trans-physeal, trans-articular suture anchor across a joint as a means of internal stabilisation has not previously been described. This study assesses the damage caused by the procedure to the immature porcine hip.

Methods: Six twelve week old pigs underwent unilateral hip surgery. Anteroposterior pelvic radiographs were taken preoperatively and six weeks post-operatively. The acetabular index and diameter of the femoral head ossific nucleus of both hips were measured and compared. Specimens were analysed macroscopically for femoral head diameter, acetabular dimensions and for evidence of gross chondrolysis. Histological analysis was performed to assess the presence of articular chondrolysis and proximal femoral physeal arrest.

Results: In four out of six specimens the rate of change of the acetabular index slowed as compared to the unoperated side, though none worsened. The diameter of the femoral ossific nucleus continued to increase in size at a similar rate to the unoperated side on radiological examination. Similar findings were seen with the macroscopic analysis. Gross and histological analysis of the articular cartilage showed only local areas of chondrolysis, related to the drilling. Metaphyseal growth at the proximal femoral physis was unaffected by the procedure.

Discussion: The use of a trans-articular suture-anchor across the hip appears to cause marginal retardation of acetabular development in the normal hip. The trans-physeal approach to the hip does not appear to affect proximal femoral physeal or epiphyseal growth in the short-term, and the presence of a bioabsorbable suture within the joint did not result in chondrolysis.

Introduction: Despite early screening, infants continue to present late ( > 4 months) with DDH. The impact of late diagnosis is significant. Established DDH causes significant morbidity and may have major medicolegal implications.

Aim: To review the incidence of late presenting DDH nationally for a single year and assess the patterns of referral. To identify the reasons for the late presentation of DDH in the presence of early clinical screening.

Methods: In a retrospective study all cases of late DDH presenting in 2004 were identified using inpatient database. Patient records were retrieved and data collected.

Results: Fifty nine cases of DDH were diagnosed at greater than 4 months. There was an additional 26 cases of isolated acetabular dysplasia treated at greater than four months.

The mean age of diagnosis was 14.6 months (range 4–72). Many of the late referrals had risk factors for DDH.

Conclusion: Despite routine clinical screening at birth and six weeks, children continue to present with late DDH. This represents a significant workload for our tertiary unit.