Background

Controversy persists regarding preference between Herbert and Acutrak screw for internal fixation of scaphoid non-union. Acutrak screw has been shown to have better biomechanical compression properties than Herbert screw in the laboratory setting. The aim of this study was to assess the clinical, radiological and functional outcome of patients treated with the two different screw systems.

Introduction

It is well established that non-union of the scaphoid requires operative intervention to achieve stable union, restore scaphoid anatomy and prevent further degenerative change. Acutrak screw has been shown to have better biomechanical compression properties than the Herbert screw in the laboratory setting. The aims of the study were to assess the rate of union, the functional outcome and post- operative complications of patients with the two different screw systems.

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.

Backgroud: Revision total knee arthroplasty (TKA) consumes considerably more resources than primary TKA. Management of infected arthroplasty has been shown to require even more resources in terms of inpatient stay, microbiological investigation, multiple stage procedures and more complex implants than treatment of aseptic failures. We investigated the trends in cost of revision TKA over a 10 year period.

Patients and Methods: Between 1997 and 2006, 189 patients underwent revision total knee arthroplasty in our institution. The perioperative data was available for 181 of these (95.77%). Data collected included age, gender, diagnosis, number of revisions length of stay, operative time, blood loss, number of units of blood transfused and ASA grade. Financial data included cost of implants and instrumentation, cost and number of bed-days, investigations and treatment. In the case of 2 stage revisions involving 2 admissions, the cumulative data was compiled as a single episode.

Results: The study group comprised 123 females (65.07%) and 66 males (34.93%). The mean age for both groups was 68.97 (range of 20 to 91years), with a 6.7% increase in mean age over the ten year period (66.75 to 71.19). The mean ASA score dropped from 2.67 in 1997 to 2.23 in 2006. The number of revision surgeries per year increased over the study period from 8 to 36. The number of TKA revisions for infection over the 10 years was 18(9.5%).

The mean length of stay for revision due to aseptic loosening in 1997 was 14.3 days. The average length of stay for revision for infected arthroplasty was 35 days. In 2006, the length of stay increased to 65 days for infected arthroplasty and 15.03 days for aseptic cases.

The mean total cost of aseptic revision per patient was 12,409.92 (range 8,822.58–13,559.65) euro in 1997 with revisions for infection costing 20,888.66 euro, a difference of 68.32%.

The industry cost of implants increased by 32–35% (€3119–€4371 and €4216–€5800) between 1999 and 2006 depending on implant selection. There was a 20– 42% increase in generic hospital costs (admission, investigation and treatment related costs) in the same period.

Conclusion: With increasing life expectancy and increased indication for primary arthroplasty more patients are coming to revision surgery. The cost of Revision TKR has increased steadily over the last 10 years. Revision TKR for infection remains significantly more expensive than revision for aseptic loosening or other causes and provides a significant financial burden on orthopaedic services. Infected arthroplasty incurs significantly greater cost and every precaution should be taken to avoid infection in total knee arthroplasty.

Introduction: Despite the documented benefits, some countries have yet to agree on the establishment of a national arthroplasty registry.

Aim: The objective of this study was to determine the opinions regarding the establishment of an Irish National register from the Consultant Orthopaedic Surgeons and Senior Orthopaedic trainees in Ireland. We also aim to find the possible reasons why a national joint register has not been established in Ireland.

Method: We have undertaken a questionnaire study to sample the opinions of the Consultant orthopaedic surgeons and Specialist registrars(SR), regarding establishment of an Irish national joint register. The questions asked related to opinions about the setting up, purpose and maintenance of an Irish National Joint Register.

Results: A total of 79 responses were received of 114 questionnaires distributed (a 69% first response rate). 97% believe it is time we set up a registry, 94% will contribute and 81% say it should be made compulsory for unwilling Surgeons and Hospitals to participate. 82% of respondents felt the set up cost should be borne by the government (Health Service Executive). Only10% of consultants agreed that the IOA should be involved in the cost bearing. Despite the overwhelming support for a national register, privacy and liability issues were major concern. 58% of the total respondents strongly agree/agree that access to registry report by the general public can expose surgeons and Hospitals to a medicolegal loophole; hence access to database should be restricted. 78% strongly agree/agree that the registry data may be used as benchmarking tools by the administrators of health-care systems to discriminate methods, implants, surgeons and hospitals, which are found to be underperforming.

Conclusion: There are considerable logistical challenges involved in the establishment of any registry. Other countries have done it successfully, and the benefits are well documented. This subject has endorsement from the Professionals as demonstrated by this study. In a litigious society such as ours, legislation may be required to further protect the integrity of a national joint replacement registry to ensure that the data are used as intended—to serve as an early warning system for premature device failure and to improve outcomes for our patients.

Background: Unicondylar knee arthroplasty (UKA) are being expanded to include younger patients with more active lifestyles because of its minimally invasive nature. Prior to expanding this role, it is important to examine mode of failure and implication of conversion to TKA in the low demand elderly patients.

Aim: To ascertain the modes of early failure of unicondylar knee Arthroplasty and assess whether the conversion to TKA improved the functional scores, range of motion, pain, and patient satisfaction.

Method: A retrospective study to evaluate the results of 14 revision procedures after failed unicompartmental knee arthroplasty (UKA). Patients’ operative charts were reviewed. Details of modes of failure, technical difficulty of revision including exposure, component removal, and management of bone loss were noted. Post operative functional outcome was assessed using WOMAC osteoarthritis index and SF-36.

Result: Total of 106 primary unicondylar knee arthroplasty procedures was performed between 2003 and 2007 in our institution. Oxford unicondylar implant was used in all patients. 13.21% of these were revised to total knee replacement. Revisions were performed 4 months to 36 months after the primary procedure; 86% of these were required within the first 12 months. The average time to failure was 15.6 months.

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.

Conclusion: Despite the advantage of minimally invasive UKA, early failure can occur in the face of good surgical technique. The higher long-term success rate claimed by implant manufacturer is challengeable and patient should be informed during consent.

Background: Infected total knee arthroplasty causes significant morbidity to patients and also challenges to surgeons to provide a functional mobile knee joint.

Aim: Present a 10-year review (1997 to 2006) of all the revision total knee replacements performed for infection in our centre.

Methods and Materials: Data including the demographics, ASA grade, blood loss, blood transfusions, length of stay, laboratory investigations including culture and sensitivity of the deep swabs. The sensitivity and specificity of pre-operative CRP and ESR were related to culture results. Post operative complication was recorded. The financial implication of the whole treatment was calculated by applying the prescribed cost by the Voluntary health insurance limited.

Results: Revisions for suspected infection constituted 14.8% (28 out of 189 cases) of the total revision knee procedures performed during the period. All the patients underwent 2 staged revision knee Arthroplasty. The mean age was 68.6 (46–83 yrs). The mode for ASA grade was 2. The average blood loss was 2 litres and the mean blood transfusion units per case were 3.8 units. The average length of stay was 42.25 days, a 24.32 days longer than aseptic revisions.

46.4% of the cases had positive cultures from the deep tissues. Staphylococcus species were responsible for 62% of cases, while enterococci, pseudomonas, streptococcus pneumonia, and MRSA have similar occurrences. The mean total cost per case was € 21,895 (13,597 for aseptic revision) a 61% increase in cost for cases revised for non septic reasons.

Conclusion: Revision Total knee replacement for infection remains significantly more expensive than revision for aseptic loosening or other causes and provides a significant financial burden on orthopaedic services. Every precaution should be taken to avoid infection in total knee arthroplasty.