Introduction: Total knee replacement (TKR) is an established and successful treatment option for symptomatic osteoarthritis of the knee. Arthroplasty surgeons, however, continue to debate the merits of posterior cruciate ligament (PCL) preservation or resection. Published literature on this subject has not demonstrated a significant clinical difference in outcome in matched subjects. Deliberate PCL resection during non-posterior stabilised TKR has also been shown to have similar outcomes.

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.

Patients and Methods: Patients awaiting TKR were prospectively enrolled into this study. Plain radiographs and an MRI scan of the knee were performed. Using coronal and sagittal images and the available software, the cross sectional area of the tibial PCL footplate was determined along with its location relative to the tip of the fibular head. Plain x-rays of the knee were performed postoperatively. Using a number of pre-determined markers we estimated the impact of the operative tibial cut on the PCL footplate.

Results: Twenty-five patients were enrolled into this study. There were 7 male and 18 female patients, mean age: 69 years. The vast majority of implants were AMK (80%), with a mean posterior slope cut of 3.6 degrees (range 0–7) and mean spacer height 11.4 mm (range 8–16).

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 mm²versus Females: 75 mm²; t-test, p < 0.005]. The inferior most aspect of the PCL footplate was located on average 1 mm above the superior most aspect of the fibular head (range: 10 mm below to 7 mm above).

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).

Conclusions We have found a wide variation in the size and location of the tibial PCL footplate when referenced against the fibular head.

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.

Method: This prospective study analysed 164 male patients who underwent primary arthroplasty between September 2004 and March 2005 inclusive. Patients who had previous urological intervention for obstructive symptoms were excluded from the study. Upon admission and prior to surgery, all patients answered an 8-point urinary symptom questionnaire and were tested on their ability to micturate while supine.

Result: 34 patients required urinary catheterisation – 130 did not. The average age of the catheterised group was 69.5+/−10.7 years (range 45–90) and the non catheterised group was 65.2+/−10.5 years (range 33–85). There was no difference between these groups (p=0.134, ANOVA). Similarly, there was not difference (p=0.919, ANOVA) between the blood loss in the 2 groups, 880.6+/−455.5 mls and 895+/−533.7 mls respectively. With regards to the symptom questionnaire, the average score in the catheter group was 3.1+/−2.4 and the non-catheter group was 2.0+/−1.8 (p=0.034, ANOVA). The ability to micturate in a supine position was of no predictive value with 22 patients in the catheter group able to do so.

Conclusion: These results show the value of a urinary symptom questionnaire used pre-operatively in predicting those who may require post-operative urinary catheterisation. By appropriate use of this tool, patients with potential for post-operative retention may be identified before surgery. Consequently, this group should be catheterised pre-operatively thus reducing their risk of infection.

Aims: Rugby is a popular sport in Ireland, with over 100,000 players registered with the Irish Rugby Football Union (IRFU) at all levels. We report a 10 year series of spinal injuries presenting to the National Spinal Injuries Unit (NSIU) at the Mater Misericordiae University Hospital.

Methods: A large series of spinal injuries in rugby players was isolated utilizing the NSIU database, HIPE and data from the IRFU. An extensive chart review and telephone interview was performed in all cases to determine age, mechanism of injury, possible aetiological factors, anatomic location of injury, American Spinal Injuries Association (ASIA) scores, current level of activity and response to rehabilitation.

Results: From 1994 to 2004, 22 rugby players with spinal injuries necessitated admission to the NSIU. Twelve patients (54%) presented with neurology. The average age at time of injury was 21.1 years (range 14 – 44 years) and all patients were male. The average length of hospital stay was 10.1 days (range 1 – 45 days). Twenty patients had cervical spine injuries. The most common mechanism of injury was hyperflexion of the cervical spine, with C5/C6 most commonly injured. Fifteen injuries occurred at adult level, the remainder at schoolboy level. Seventeen (77%) players were injured whilst playing First Team rugby. Eleven (50%) players were injured in the Backs, the remainder in the Forwards. 68% of injuries occurred in the tackle situation and 32% in the scrums, rucks and mauls. Winger, Full Back and Hooker were the playing positions at greatest risk.

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.

Conclusion: Rugby as a sporting pastime is not without risk. During the ten year period under review, 8 players suffered permanent disability as a direct result of participation in competitive rugby. Serious spinal injuries continue to occur and recent rule changes have had little effect in reducing their incidence.

Aims: Rugby is a popular sport in Ireland, with over 90,000 players registered with the Irish Rugby Football Union (IRFU) at all levels. We report a 10 year series of spinal injuries presenting to the National Spinal Injuries Unit (NSIU) at the Mater Misericordiae University Hospital.

Methods: A large series of spinal injuries in rugby players was isolated utilizing the NSIU database, HIPE and data from the IRFU. An extensive chart review and telephone interview was performed in all cases to determine age, mechanism of injury, possible aetiological factors, anatomic location of injury, American Spinal Injuries Association (ASIA) scores, current level of activity and response to rehabilitation.

Results: From 1994 to 2004, 22 rugby players with spinal injuries necessitated admission to the NSIU. Twelve patients (54%) presented with neurology. The average age at time of injury was 21.1 years (range 14 – 44 years) and all patients were male. The average length of hospital stay was 10.1 days (range 1 – 45 days). Twenty patients had cervical spine injuries. The most common mechanism of injury was hyperflexion of the cervical spine, with C5/C6 most commonly injured. Fifteen injuries occurred at adult level, the remainder at schoolboy level. Seventeen (77%) players were injured whilst playing First Team rugby. Eleven (50%) players were injured in the Backs, the remainder in the Forwards. 68% of injuries occurred in the tackle situation and 32% in the scrums, rucks and mauls. Winger, Full Back and Hooker were the playing positions at greatest risk.

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.

Conclusion: Rugby as a sporting pastime is not without risk. During the ten year period under review, 8 players suffered permanent disability as a direct result of participation in competitive rugby. Serious spinal injuries continue to occur and recent rule changes have had little effect in reducing their incidence.

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.

Introduction: An arthroplasty database, such as the Swedish Hip Registry, provides a crude means of quality control over the sizable number of prosthetic implants available on the market today. It provides relatively rapid feedback on the performance of orthopaedic devices and surgical techniques, allowing inferior devices and methods to be discontinued. The maintenance of an arthroplasty register is inexpensive and of enormous benefit to the patient. At present, there is no nationwide arthroplasty register in operation in the Republic of Ireland.

Aim: To develop an arthroplasty register which prospectively captures all clinical, radiographic and medical outcome data on patients undergoing surgery in our unit

Materials and methods We are using an existing computer software programme (Bluespier Patient Manager) to capture our information, although our database is stored independently of this.

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.

Study design: We prospectively studied all patients with cervical spine fractures who were admitted to the National Spinal Injuries Unit from 1 July 2000 to 1 March 2001. Anthropometrical measurement of head circumference, neck circumference, chest circumference, and neck length were analysed. Ages ranged from 18 to 55 years, and all patients with concomitant cervical pathology were excluded from the study. Mechanism of injury involved flexion/extension type injuries in all cases; those with direct axial loading were excluded. A control group of 40 patients (age 18–50 years) involved in high velocity trauma with associated long bone fractures, in whom cervical injury was suspected, but who were without any cervical fracture, or associated pathology, were similarly measured.

Results: Our analysis revealed a statistically significant increase in chest size in the male control group versus the male fracture group (97.89 cm versus 94.19 cm, P < 0.05, Student’s t-test). There was a correspondingly significant increase in chest circumference between the female controls versus the female fracture group (92.33 cm versus 88.88 cm, P < 0.05, Student’s t-test). Our results revealed no statistical difference in head circumference, neck circumference, or neck length between each of the groupings. These results indicate a proportionately larger chest may be a protective factor in cervical spine fractures.

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

Study Design: A retrospective review of the functional outcome of neurologically intact patients with burst fractures of the first lumbar vertebra.

Objective: To assess the functional outcome of patients treated either surgically or conservatively following burst fractures of L1.

Methods: A retrospective review of 38 neurologically intact patients with burst fractures of L1 was performed. Follow-up clinical evaluation was obtained from 26 patients, eleven of whom were treated surgically and fifteen of whom were managed conservatively. Patients were assessed with regard to pain, employment status, ability to partake in recreational activities and their overall satisfaction with treatment. Radiographic evaluation of anterior body compression and vertebral kyphosis was performed at the time of injury. Computed tomography scanning of spinal canal compromise was also recorded at the time of injury. Subsequent recordings of vertebral kyphosis were assessed at the time of remobilisation and at 3-month follow-up evaluation.

Results: Mean follow-up time for the 26 patients was 43.02 months. At final clinical follow-up of the fifteen patients managed conservatively, 6 patients (40%) had little or no pain; 12 patients (80%) had returned to work with 6 (40%) stating that they had little or no restrictions in their ability to work; 8 patients (53%) had returned to the same level of recreational activity as prior to their injury with 7 (47%) stating they had little or no restrictions in their ability to participate in recreational activities. One patient (9%) reported being very dissatisfied with the operative treatment of their spine fracture.

No correlation was found between kyphotic deformity, extent of canal compromise and clinical outcome.

Conclusions: Non-operative management of burst fractures of the first lumbar vertebra is a very safe and effective method of treatment. It reduces hospitalisation time and avoids the costs and risk of surgery. Patients return to the functional activities of daily living quickly and have a better clinical outcome when compared with operative management.

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.

Introduction: Fractures of the sternum result from a direct blow or from an indirect mechanism with hyperflexion of the spine. The association between spinal injury and sternal fractures has been reported but is commonly overlooked and underestimated.

Aims: Our aim was to study the clinical and radiological effects of an attendant sternal fracture on vertebral fractures. Berg first described the extra stability afforded to the thoracic spine by the sternal-rib complex and the adverse effects of damage to this “4th column” apropos of 2 cases.

Materials and Methods: None patients were admitted to our unit from October 1996 to August 2001 suffering from vertebral fractures and concomitant sternal fractures. The clinical notes and plain film radiographs of these patients were studied.

Results: The average age of the 9 patients (5 males and 4 females) was 33 years (range 21–73). Seven had been involved in road traffic accidents and 2 had fallen from a height. Four patients had injuries to their cervical spine, 4 to their thoracic spine and one had a lumbar spine fracture. In terms of neurological compromise, only one of the cervical groups had a neurological deficit compared to all 4 in the thoracic group (2 complete and 2 incomplete). The patient with the lumbar spine fracture suffered incomplete neurological compromise. All 6 of the patients with neurological compromise underwent surgical management. The other 3 patients were treated conservatively.

Conclusion: It has been traditionally accepted that the sternum is injured only in association with upper thoracic spine. Our findings suggest that spinal injury at lower thoracic, upper lumbar or cervical level may also be associated with sternal injuries. However, the relative severity of the vertebral injury and neurological compromise in the thoracic spine subgroup offers clear support of Berg’s “4th column” theory of thoracic spine fractures when compared to fractures of the cervical or lumbar spine with sternal injuries.

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.

Introduction: The Ganz periacetabular osteotomy aims to improve femoral head coverage in dysplastic hips. It is joint preserving procedure and therefore is ideally preformed before significant articular cartilage degeneration. One proposed advantage of this procedure is that it partially preserves the posterior column and does not disrupt the vascular supply of the main fragment. This study aims to 1) assess the role of MR imaging in the perioperative evaluation of articular cartilage and labrial tissues prior to Ganz osteotomies and 2) to document any alteration in the vascularity of the acetabular fragment post operatively.

Patient and Methods: Twenty patients (all female, average age 18.2 years) under consideration for peracetabular osteotomy for hip dysplasia and MR Studies of the pelvis as part of the perioperative assessment. Sixteen patients had follow-up imaging at 4, 12 and 26 weeks post surgery, at which time evidence of healing, oedema, vascularity and femoral head coverage were assessed.

Discussion: MR imaging has proven to be a reliable method of assessing articular cartilage health before considering pelvic osteotomy. Hopefully this will allow more appropriate selection of patients likely to benefit from this procedure. In addition MRI scanning allows clearer assessment of other articular elements, such as labium and ligamentum teres, that are difficult to visualize with plain radiographs and CT scans. A further benefit of MR scanning is that, as this study has shown the vast majority of patients who are potential candidates are female of childbearing age and it voids the use of ionizing radiation in this sensitive group of patients. This study has shown that despite some early alterations in osteotomy fragment vascularity the ultimate outcome is that vascularity is substantively unharmed by periacetabular osteotomy.

Conclusion: MR imaging is extremely useful in the perioperative workup and postoperative follow-up in patients undergoing Ganz periacetabular osteotomies.

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.

Introduction: Increased levels of IL-6 and IL-8 have been found in intervertebral disc (IVD) tissue from patients undergoing fusion for discogenic low back pain. The stimuli that induce these mediators in degenerate discs remain unknown. Impaired diffusion of nutrients and wastes to and from the nucleus pulposus (NP) is believed to be an important factor in the degenerative process. The oxygen tension and pH in the NP of degenerating discs are significantly decreased.

Aims: The aims of this study were to (1) demonstrate the ability of porcine NP to respond to a proinflamma-tory stimulus (lipopolysaccharride) in vitro, (2) investigate the effects of pH, pO₂ and glucose concentration on NP proinflammatory mediator secretion and (3) determine if methylprednisolone or indomethacin can block NP proinflammatory mediator secretion.

Methods: IVDs were harvested from 6-month old pigs and dissected under sterile conditions in the laboratory. 200mg samples of NP were cultured under optimal conditions (control), in a 1% O₂ environment, at pH6 and in culture medium without glucose for 72 hours. Blocking experiments were performed by culturing LPS-stimulated samples with either methylprednisolone or indomethacin for 24 hours. IL-6 and IL-8 levels were estimated by ELISA.

Results: Time and dose-response curves were generated for each experiment (results not shown). Results for the optimum dose and at 72 hours incubation were note.

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.

Aims: To correlate clinical imaging and surgical finding in patients with knee arthritis. In an attempt to identify specific lesions that correlate with the location of clinical pain.

Methods: 26 patients and 32 knees were eligible for inclusion in the study. All patients had been admitted for total knee arthroplasty. In all patients an attempt was made to correlate symptoms with radiographic findings and then intraoperative findings. A senior orthopaedic registrar carried out standard knee scores and clinical examinations, radiographs and a radiologist blindly evaluated MRI scans. The integrity of the articular cartilage as well as the menisci and ligaments were all graded.

Results: At clinical examination all patients score 70 or higher on a visual analogue scale. In eighteen patients, the maximum site of clinical tenderness was referable to the medial joint line. In seven patients symptoms were on the lateral aspect. Pain was recorded on a line diagram of the knee for analysis. MR images confirmed advanced arthritis with meniscal derangement with extrusion and maceration. Note was made of osteophyte formation, medial collateral ligament laxity and oedema and discrete osteochondral defects. Bone marrow bruising and oedema was also recorded. In nine patients subchondral cysts were identified with extensive associated bone oedema. At surgery, meniscal degeneration was identified in fifteen of twenty-six, meniscal tears were identified in six; the menisci were normal in two patients.

Discussion: These results suggest that there is a direct correlation between clinical symptoms and meniscal derangement in severe osteoarthritis. Isolated articular defects and bone marrow oedema did not correlate well with location of pain. Presence of medial collateral oedema correlated well with severity of radiological arthritis and clinical findings.

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.

Aims: To assess the impact of sleep deprivation on recovery of the patient and quality of life in the peri-operative period.

Methods: Patient cohort consisted of elective admissions for total hip replacement. All were assessed using the Epworth sleep scale, SF-36 as well as the Hospital Anxiety and depression score. Body mass index and history of insomnia or obstructive sleep apnoea were recorded. Baseline oxygen saturation was compared with postoperative overnight saturation and request for night sedation.

Results: 64 consecutive patients undergoing total hip arthroplasty surgery were eligible for inclusion in the study. Mean age 68 (43 to 85), 42 females, 22 males, 62 patients were satisfied with the result of surgery, 1 patient with hip dysplasia had a persistent leg length inequality and one complained of back pain. All patients were nursed according to standard protocol with abduction pillow while in hospital and instructions to sleep on their back while at home. 18 patients did not fully comply with this instruction while at home. There were no early dislocations with a mean follow up of 5.4 months. Mean hospital anxiety and depression scores were significantly increased following surgery mean pre-operatively (5.2), to highest level (3.4) at two weeks, (8.5) at six weeks, returning to normal levels after three months (4.2). Epworth sleep scores were similarly increased with sleep patterns returning to normal at the three month stage. Increasingly, body mass index correlated significantly with poor scores and low oxygen saturation readings. This group of patients had a predisposition to obstructive sleep apnoea, which was predicated by sleeping on their backs, they require more night sedation and analgesia.

Conclusions: Standard precautions following total hip arthroplasty are not without morbidity. Sleep deprivation leading to increased anxiety and decreased satisfaction. Increased demand for night sedation and analgesia with their resultant costs and dependence. Sleeping in the supine position may also precipitate obstructive sleep apnoea in at risk patients.

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.