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Volume 97-B, Issue SUPP_3 April 2015 Glasgow Meeting of Orthopaedic Research (GLAMOR) West of Scotland Orthopaedic Research Society

S.G.F. Abram J.B. Murray

Recent National Institute for Health and Care Excellence (NICE) guidance has advised against the continued use of the Thompson implant when performing hip hemiarthroplasty and recommended surgeons consider using the anterolateral surgical approach over a posterior approach.

Our objective was to review outcomes from a consecutive series of Thompson hip hemiarthroplasty procedures performed in our unit and to identify any factors predicting the risk of complications.

807 Thompson hip hemiarthroplasty cases performed between April 2008 and November 2013 were reviewed. 721 (89.3%) were cemented and 86 (10.7%) uncemented. 575 (71.3%) were performed in female patients. The anterolateral approach was performed in 753 (93.3%) and the posterior approach with enhanced soft tissue repair in 54 (6.7%).

Overall, there were 23 dislocations (2.9%). Dislocation following the posterior approach occurred in 13.0% (7 of 54) in comparison to 2.1% (16 of 753) with the anterolateral approach (odds ratio (OR) 8.5 (95% CI 2.8 to 26.3) p < 0.001). Surgeon grade and patient history of cognitive impairment did not have a significant impact on dislocation rate.

Patients were discharged home in 459 cases (56.9%), to a care home or other hospital in 273 cases (33.8%). 51.8% (338 of 653) returned home within 30 days. 75 died during their admission (9.3%). 30-day mortality was 7.1% and 1-year mortality was 16.6%.

Intraoperative fracture occurred in 15 cases (1.9%) of which 14 were cemented. Superficial or deep infection occurred in 33 cases (4.1%).

We recommend against the continued use of the posterior approach in hip hemiarthroplasty, as enhanced soft tissue repair did not reduce dislocation rates to an acceptable level. Our findings, however, demonstrate satisfactory results for patients treated with the Thompson hip hemiarthroplasty performed through an anterolateral approach. We suggest that the continued use of the Thompson implant in a carefully selected patient cohort is justifiable.


D. Hansom G. Ramage K. Burgess N. Gadengaard N. Millar J. Clarke

The most common bacteria in orthopaedic prosthetic infections are Staphylococcus, namely Staphylococcus Epidermidis (SE) and Staphylococcus Aureus (SA). Infection causes implant failure due to biofilm production. Biofilms are produced by bacteria once they have adhered to a surface.

Nanotopography has major effects on cell behaviour. Our research focuses on bacterial adhesion and biofilm formation on nanofabricated materials. Bacteria studied were clinically relevant from an orthopaedic perspective, SA and SE. We hypothesise that that nanosurfaces can modulate bacterial adherence and biofilm formation and may reduce orthopaedic implant infection rate.

Isolated bacteria were grown and growth conditions optimised. Bacterial concentrations were calculated by using qPCR. Statistical analysis allowed identification of optimal biofilm growth conditions. These were refined on standard, non-nanopatterned surfaces, and then control and nanopatterned polystyrene (nanopits) and titanium plates (nanowires). Adhesion analysis was performed using fluorescence imaging and quantitative PCR.

4 bacterial strains were isolated and cultured. Growth kinetics based on 24hr cultures allowed isolation of optimal media for biofilm conditions (Dulbecco's Modified Eagle Medium with additional supplements). Highest bacterial concentrations were found following 2hrs incubation with Lysozyme during qPCR. Bacterial concentration significantly increased between 30, 60 and 90 minutes incubation. Differences in percentage coverage on different polysyrene nanosurfaces (nanopits) were noted varying. This was confirmed by qPCR extractions that showed different bacterial concentrations on different nanopatterns. Titanium nanowire surfaces significantly increased bacterial adhesion (P<0.05).

Our study cultured and quantified bacterial biofilm and suggests that by altering nanotopography, bacterial adhesion and therefore biofilm formation can be affected. Specific nanopatterned surfaces may reduce implant infection associated morbidity and mortality. Clearly this is of significant benefit to the patient, the surgeon and the NHS, and may well extend far beyond the realms of orthopaedics.


S. Gupta D. Cafferky F. Cowie P. Riches I. Anthony A. Mahendra

Extracorporeal irradiation and re-implantation of a bone segment is a technique employed in bone sarcoma surgery for limb salvage in the setting of reasonable bone stock. There is neither consensus nor rationale given for the dosage of irradiation used in previous studies, with values of up to 300Gy applied. We investigated the influence of extracorporeal irradiation on the elastic and viscoelastic properties of bone. Bone specimens were extracted from mature cattle and subdivided into thirteen groups; twelve groups exposed to increasing levels of irradiation and a control group. The specimens, once irradiated, underwent mechanical testing in saline at 37°C.

Mechanical properties were calculated by experimental means which included Young's Modulus, Storage Modulus and Loss Modulus. These were all obtained for comparison of the irradiated specimens to the control group.

There were non-significant negligible changes in all of the mechanical properties of bone that were assessed with increasing dosage of irradiation. Therefore, we conclude that the overall mechanical effect of high levels of extracorporeal irradiation (300Gy) is minute, and can be administered to reduce the risk of malignancy recurrence.


A. Tanagho S. Hatab S. Roberts S. Shewale

Introduction:

Antimicrobial resistance is an important patient safety issue. Antibiotic Stewardship is one of the key strategies in tackling this problem. We present our data over a two year period from October 2011 to December 2013.

Method:

A multidisciplinary, consultant led antibiotic ward round was implemented in October 2011. This involved the consultant orthopaedic surgeon, microbiologist, pharmacist and antibiotic prescription nurse. Data from the meetings was collected prospectively over a 118 week period using a standard data form.

The case notes, prescription kardex, laboratory results including microbiology data and clinical information of patients was available at the time of the Ward round. The indications for, choice of antibiotics, duration and further treatment plan were made and a note for the case notes was dictated immediately. Changes to prescriptions were also made at the time.


O. Al Fakayh A.G. Marsh S. Patil

Ganz peri-acetabular osteotomy is commonly used to treat symptomatic hip dysplasia. It aims to increase the load bearing contact area of the hip to reduce the risk of subsequent osteoarthritis. In this study we assess the radiographic and clinical results of the procedure since its introduction to our unit.

All patients undergoing Ganz osteotomies at our unit were followed up prospectively. Data collected included patient demographics and pre- and post-operative functional scores (Harris and Non-arthritic hip scores). In addition, acetabular correction was evaluated on pre-and post-operative radiographs (using Centre-Edge angle and Tonnis angle). Complications were also noted.

Overall 50 procedures were performed between 2007 and 2013 with median follow-up of 3 years (1 – 7 years). The majority of patients (90%) were female. Average age at time of surgery was 29 years (16–49). There were significant improvements in pre- and post-operative median functional scores (Modified Harris Hip Score = 49 versus 64, p=0.001), Non-arthritic Hip Score = 42 versus 56, p=0.007). Median Centre Edge Angle improved from 16 degrees pre-operatively (range = 7–31 degrees) to 30 degrees post-operatively (18–33) degrees), p<0.0001. Similarly, pre-operative Tonnis angle improved from 18 degrees (9–38) to 7 degrees (2–14), p<0.0001. Five patients developed post-operative complications: 2 superficial wound infection, 1deep infection requiring hip washout and antibiotic treatment and 2 patients subsequently requiring total hip replacements.

We have shown that the Ganz peri-acetabular osteotomy can be effective for the treatment of painful hip dysplasia improving both functional and radiographic outcomes. However, patient selection is a key factor.


S. Hatab A. Tanagho S. Ansara

The patella is an important component of the extensor mechanism of the knee. Patellar fractures need to be fixed if displacement occurs more than 2 mm. Transverse fractures comprise the largest category. Several different techniques for internal fixation have been employed.

The aim of this work was to evaluate the results of treatment of transverse patellar fractures with figure of eight wiring through cannulated screws.

Twenty patients were included in the study, all suffering from displaced transverse patellar fractures. All were treated by open reduction and internal fixation with figure of eight tension band wire through 4.0 mm cannulated screws.

All patients were assessed after 1 month, 3 months and 6 months according to a modified Hospital for special surgery (HSS) knee scoring system. Because varus and valgus knee alignment and stability are not affected by patellar fracture fixation, the ten points assigned to these functions are eliminated, making the highest score ninety points. Excellent results are considered with points from 75 to 90, good from 60 to 74, fair from 50 to 59 and poor with points below 50.

The final results of the study showed fourteen patients (70%) had excellent results, five (25%) good result, one (5%) fair result and no patient had a poor result. There was a statistically significant improvement of the patients' score throughout the follow up period.

The complications occurred included knee pain in one patient (5%), loss of terminal flexion of knee occurred in three patients (15%), one patient lost 30 degrees, another lost 20 degrees while the last lost 10 degrees. There were no cases with extension lag in this series.

Treatment of patellar fractures using figure of eight wiring through cannulated screws is an easy technique which gives good stability leading to good results with a low complication rate.


R. Bhattacharyya A. Ker Q. Fogg J. Joseph

Background:

The Lateral Intercondylar Ridge (LIR) gained notoriety with arthroscopic trans-tibial Anterior Cruciate Ligament (ACL) reconstruction where it was mistakenly used to position the ‘over the top’ guide resulting in graft malposition.

With anatomic ACL reconstruction some surgeons use the same ridge to define the anterior margin of the ACL femoral insertion in order to guide graft placement. However there is debate about whether this ridge is a consistent and reliable anatomical structure.

The aim of our study was to identify whether the LIR is a consistent anatomical structure and to define its relationship with the femoral ACL insertion.

Methods:

In the first part, we studied 23 dry bone specimens. Using a digital microscribe, we created a 3D model of the medial surface of the lateral femoral condyle to evaluate whether there was an identifiable bony ridge.

In the second part, we studied 7 cadaveric specimens with soft tissues intact. The soft tissues were dissected to identify the femoral ACL insertion. A 3D reconstruction of the femoral insertion and the surface allowed us to define the relationship between the LIR and the ACL insertion.


L. Russo K.B. Ferguson A. Winter M. MacGregor G. Holt

Introduction

Acute kidney injury is a recognised post-operative complication in primary joint replacement. Recently it has been demonstrated that antibiotic regimen can significantly impact on the proportion of patients who develop acute kidney impairment post-operatively. Within our unit an increased rate of acute kidney injury had been noted post-operatively over the last 5 years. This increase followed the introduction of a rapid recovery protocol for arthroplasty patients. Our aim was determine whether we could identify a causative factor or those who were at increased risk of post-operative renal impairment.

Methods

Data were collected for 413 patients initially retrospectively but continued prospectively. Univariable and multivariable analysis was performed to determine any causative factors. The primary increase was 150% increase in baseline creatinine, but as some authors recognise an increase in 125% this was also analysed.


M. Siddiqui R. Farro K. Shah J. Roberts

Background-

Health care is best delivered face to face, doctor to patient. However, in some places like Scotland, patients can be in remote areas, far from the nearest health care provider. Medical video conferencing (VC) enables patients and doctors to meet for consultations from wherever they may be without the need for travel, and is already used widely in countries like Australia and Canada.

Aim-

To do a pilot study of using the existing VC facility at our hospital for surgical pre-assessment of patients for elective foot/ankle and lower limb arthroplasty surgery. Methods- A prospective pilot study was performed at our hospital after approval from our ethics committee. Patient-records were vetted to include/exclude from the study and cases considered as “straightforward” were included. Two separate rooms with VC facility were set up in the orthopaedic outpatients, one with the patient and a trained physiotherapist, while the surgeon used the second room to discuss patient's complaints, do a physical examination, and discuss surgery where appropriate.


N. Mackay F. Mahmood K. Chan K. Baird S. McMillan J. Logan C. Dowell R. Miller

Ankle lateral ligament complex injury is common. Traditional ‘Brostrum’ repair, performed either open or arthroscopically, still has a protracted post-operative period. The ‘Internal Brace’ provides a scaffold for the ligament repair and acts as a ‘check-rein’ preventing further injury.

16 patients with ankle instability and injury to the Anterior-Talo-Fibular-Ligament (ATFL) confirmed on MRI were identified. All had completed a period of conservative treatment. All had symptoms of pain in the region of the ATFL and described a feeling of instability. Surgery was performed under general anaesthetic and regional popliteal block. Anterior ankle arthroscopy demonstrated a positive ‘drive through’ in all cases. The ATFL was absent and in the majority replaced by incompetent scar. Scar tissue was removed from the anterior aspect of the ankle allowing visualisation of the fibula and lateral talar neck. Using the Internal Brace system (Arthrex), a 3.5mm swivel-lock with fibre-tape was placed into the fibula. With the ankle in plantar flexion, to allow appropriate tensioning, the distal end of the fibre-tape was secured to the talar neck, at a 45 degree angle, with a 4.75mm biotenodesis screw. The patient was placed into a moon-boot for 7–10 days and mobilised fully weight-bearing. Pre-op score, using EDQ-5, MOXFQ, AOFAS and visual analogue scores, with post-op PROMS were performed.

All patients reported improvement in their symptoms at 6 week visit. The majority were back to normal activities at 12 weeks. The few that were not, had missed physiotherapy appointments for various reasons. There were no infections and no implant failures.

Arthroscopy allows direct visualisation for accurate placement of the Internal Brace. Post-operatively recovery is expedited due to the stability provided by the ‘Brace’, permitting a more aggressive rehabilitation programme. The greatest potential is arguably for the elite athlete, where an accelerated return to full activity has significant occupational implications.


A. Powell I. Mcgraw C. Shaw O. Alanie I. Anthony G. Ayana

Introduction:

Mayo 2A Olecranon fractures are traditionally managed with a tension band wire device (TBW) but locking plates may also be used to treat these injuries.

Objectives:

To compare clinical outcomes and treatment cost between TBW and locking plate fixation in Mayo 2A fractures.


H. Bradman S. Patil D. Martin A.G. Marsh

Postgraduate training in orthopaedics has traditionally been delivered through an apprenticeship model. However, junior doctor working patterns have more recently moved away from a team based structure, potentially affecting training experience. We aimed to compare the perceived quality of training between medical students, junior non-orthopaedic trainees and orthopaedic specialty trainees.

We conducted an anonymous questionnaire of all medical students and trainees rotating through our unit over 24 months. The questionnaire contained 6, 10-point Likert rating scale questions and free text responses. Results were collated and analysed according to training stage.

Of 82 questionnaires distributed, 60 (73%) were completed (18 specialty registrars, 22 junior trainees and 20 medical students). Junior trainees consisted of 8 GPSTs and 14 Foundation Year (FY2) doctors, only one of whom had specifically chosen an orthopaedic placement.

Median Likert rating of training experience was (1 = very poor, 10 = excellent): ST4-ST8 = 8 (range 7–9), ST1-ST3 = 7 (6–9), GPSTs/FY2s = 4 (2–5) and medical students = 8 (7–10). Further analysis of junior non-orthopaedic doctors' training experience showed that placement induction, organisation of formal teaching and opportunities for training out with formal sessions were rated as poor. However, content of delivered teaching was rated highly. Free text responses identified several barriers to training including being too busy on wards and no opportunity for protected teaching.

Our study shows that junior non-orthopaedic trainees feel their training experience during orthopaedic placements is much poorer than orthopaedic trainees and medical students. Time constraints and less team based working patterns may detract from their teaching opportunities. In addition, junior doctors rotating through orthopaedic units now have a wider spectrum of career interests with heterogeneous training needs. Therefore, orthopaedic departments may need to adopt a more targeted training programme that recognises individual training needs if junior doctor training is to improve.


G. Augustithis J. Huntley

‘Safety’ is at the centre of surgical practice with the aim of minimising the risks of complications and adverse events. Much evidence, based on either retrospective case series or prospective cohorts, concerns the frequency of adverse events. There may be a temptation to describe a procedure as ‘safe’ if no – or few – serious adverse events (the numerator) have occurred out of a number of procedures performed (the denominator). In 1983, Hanley and Lippman-Hand described a simple algorithm to calculate the 95% upper Confidence Interval for data sets in which the numerator is zero (ie series in which there no adverse events). Paediatric orthopaedics suffers from small datasets which may make its researchers especially prone to the erroneous attribution of procedures being ‘safe’. The aim of the current study was to formally assess the evidence on which paediatric orthopaedic surgical procedures are described as ‘safe’. In particular, the objective was to ascertain the proportion of studies describing a procedure as ‘safe’ which achieved a 95% upper limit Confidence Interval of risk of 5% for major adverse events.

We examined all papers published by the Journal of Paediatric Orthopaedics in the previous 5 years searching for the single term ‘safe’. 84 papers were returned and 71 were considered appropriate for analysis. Of these 60 papers positively identified their intervention as ‘safe’. These papers were read in full and the number of interventions was recorded along with the rate of complication. 66 data sets were created and the 95% upper confidence interval was calculated for complication rates. Only 16 out of 66 data sets could safely predict a major complication rate of under 5%.

Our work would tend to suggest that a failure to apply proper statistical tools is leading to procedures being erroneously classified as safe in the published literature.


M. Halai A. Augustine N. Holloway D. MacDonald A. Mohammed RDM. Meek S. Patil

Two major challenges in arthroplasty are obesity and antibiotic resistance. This study was performed to characterise the organisms responsible for deep infection following total hip arthroplasty and to determine if obesity affected the microbiology profile.

A retrospective analysis of the national surgical site infection register was made to obtain data regarding deep infection following 10948 primary total hip arthroplasty (THA) from 1998–2013, with a minimum of 2 year follow-up.

Of all the primary THAs performed, there were 108 deep infections (56 patients had a BMI >30 (obese) and 52 patients <30). There were no significant differences between cardio-respiratory disease, smoking and alcohol status, and diabetes between the 2 groups. Over the last 15 years, staphylococcus aureus continues to be the most frequently isolated organism. Infection with multiple organisms was found exclusively in obese patients. Furthermore, in obese patients, there was a linear increase with methicillin resistant staphylococcus aureus (MRSA) infections and streptococcus viridans.

On this basis, we recommend careful selection of antibiotic therapy in obese patients, rather than empirical therapy, which can be especially important if there is no growth in an infected THA. In addition, a preoperative discussion regarding dental prophylaxis against streptococcus viridans may be warranted.


A.S. Brydone F. Henderson D. Allen

Since the establishment of our department a multi-modal approach to thromboprophylaxis that uses aspirin for chemical prophylaxis was adopted. In accordance with the latest national recommendations, our routine chemical prophylaxis following arthroplasty was changed to rivaroxaban in 2012 and then dalteparin in 2013.

This study aimed to compare venous thromboembolism (VTE) rates during the use of the aspirin-based protocol used from 2004 to 2011 with recent, rivaroxaban and dalteparin-based guidelines.

Outcome data from ISD Scotland was retrieved and radiology reports performed for CT pulmonary angiograms and lower limb doppler ultrasound scans in our institution were assessed to identify cases of VTE following primary hip or knee arthroplasty. The incidence of pulmonary embolism (PE) and proximal deep venous thrombosis (DVT) was calculated for each year and compared using a Chi-squared test. Additionally, the change in extended thromboprophylaxis regimen was surveyed by recording the discharge prescriptions for consecutive arthroplasty patients for March every year.

There were 90 radiologically confirmed cases of DVT or PE between 2004 and 2011 (incidence of 0.71%). The DVT/PE rate was subsequently 0.67% in 2012 and 0.69% in 2013, with a further 29 cases identified. This does not represent a significant change in the venous thromboembolism rates and remains below the national incidence of VTE (1.06%).

Aspirin alone was used as chemical thromboprophylaxis in 80.8% of patients from 2004 to 2011, 50.9% in 2012, and 12.1% in 2013.

The incidence of VTE at our centre remains favourable to national figures, but the modification of thromboprophylaxis guidelines will incur additional financial costs and has not had a significant reduction on the rate of VTE.


A.G. Marsh E. Crighton L. Yapp M. Kelly B. Jones R.M.D. Meek

Successful treatment of periprosthetic joint infection involves surgical intervention and identification of infecting organisms to enable targeted antibiotic therapy. Current guidelines recommend intra-operative culture sampling to include at least 4 tissue samples and for each sample to be taken with a separate instrument.

We aimed to review current revision arthroplasty practice for Greater Glasgow, specifically comparing intra-operative sampling technique for infected revision cases with these guidelines.

We reviewed the clinical notes of all patients undergoing lower limb revision arthroplasty procedures in Greater Glasgow Hospitals (WIG, GRI, SGH) from July 2013 to August 2014. Demographics of all cases were collected. For revision procedures performed for infection we recorded details of intraoperative samples taken (number, type and sampling technique) and time for samples to reach the laboratory. Results of microbiology cultures were reviewed.

Two hundred and fifty five revision arthroplasty procedures (152 hips, 103 knees) were performed in the 12 month study period. Of these 57 (22%) were infected cases (28 hips, 29 knees). These cases were treated by 14 arthroplasty surgeons with a median number of 3 infected cases managed per surgeon (range 1–11). 58% of cases had the recommended number of tissue samples taken. The median number of microbiology samples collected was 4 (range 1–14). Most procedures (91%) had no documentation of whether separate instruments were used for sampling. Number of tissue samples taken (≥4, p=0.01), time to lab (<24 hours, p=0.03) were significantly associated with positive culture results.

In Greater Glasgow, a large number of surgeons manage infected arthroplasty cases with variability in intra-operative sampling techniques. Sample collection adheres to guideline recommendations in 58% cases. Adhering to guideline standards increases the likelihood of positive tissue cultures. Implementation of a standardised approach to intra-operative sampling for infected cases may improve patient management.


A.S. Brydone D.S.S. Morrison R.D.M. Meek M.J. Dalby N. Gadegaard

Poly-ether-ether-ketone (PEEK) is a biomaterial commonly used for spinal implants and screws. It is often desirable for orthopaedic implants to osseointegrate, but as PEEK is biologically inert this will not occur. The aim of this project was to determine if injection mould nanopatterning can be used to create a make PEEK bioactive and stimulate osteogenesis in vitro.

PEEK substrates were fabricated by injection mould nanopatterning to produce near-square (NSQ) nanopatterned PEEK and planar (FLAT) PEEK samples. Atomic force microscopy (AFM) and scanning electron microscopy were used to characterize the surface topography. Human bone marrow stromal cells (hBMSCs) were isolated from patients undergoing primary hip replacement operations and seeded onto the PEEK substrates. After 6 weeks the cells were stained using alizarin red S (ARS) stain (to detect calcium) and the von Kossa technique (to detect phosphate) and analyzed using CellProfiler image analysis software to determine: surface coverage; cell number; and expression of either calcium (ARS stain) or phosphate (von Kossa technique).

ARS stain showed calcium expression (quantified relative to the number of cells) was increased on NSQ PEEK compared to FLAT PEEK (not statistically significant) and the surface coverage was similar. Von Kossa staining revealed more surface coverage on FLAT PEEK (69.1% cf. 31.9%), cell number was increased on FLAT PEEK (9803 ± 4066 cf. 4068 ± 1884) and phosphate expression relative to cell number was also increased (seven-fold) on NSQ PEEK (P < 0.05) compared to FLAT PEEK.

Although hBMSCs may adhere to NSQ PEEK in smaller numbers, the cells expressed a relatively larger amount of calcium and phosphate. This indicates that the cells adopted a more osteoblastic phenotype and that nanopatterning PEEK induces hBMSC differentiation and stimulates osteogenesis. Injection mould nanopatterning therefore has the potential to improve osseointegration of PEEK implants in vivo.