Gram-negative prosthetic joint infections (GN-PJI) present unique challenges in management due to their distinct pathogenesis of biofilm formation on implant surfaces. To date, there are no animal models that can fully recapitulate how a biofilm is challenged in vivo in the setting of GN-PJI. The purpose of this study is to establish a clinically representative GN-PJI in vivo model that can reliably depict biofilm formation on titanium implant surface. We hypothesized that the biofilm formation on the implant surface would affect the ability of the implant to be osseointegrated.

The model was developed using a 3D-printed, medical-grade titanium (Ti-6Al-4V), monoblock, cementless hemiarthroplasty hip implant. This implant was used to replace the femoral head of a Sprague-Dawley rat using a posterior surgical approach. To induce PJI, two bioluminescent Pseudomonas aeruginosa (PA) strains were utilized: a reference strain (PA14-lux) and a mutant strain that is defective in biofilm formation (DflgK-lux). PJI development and biofilm formation was quantitatively assessed in vivo using the in vivo imaging system (IVIS), and in vitro using the viable colony count of the bacterial load on implant surface. Magnetic Resonance Imaging (MRI) was acquired to assess the involvement of periprosthetic tissue in vivo, and the field emission scanning electron microscopy (FE-SEM) of the explanted implants was used to visualize the biofilm formation at the bone-implant interface. The implant stability, as an outcome, was directly assessed by quantifying the osseointegration using microCT scans of the extracted femurs with retained implants in vitro, and indirectly assessed by identifying the gait pattern changes using DigiGaitTM system in vivo.

A localized prosthetic infection was reliably established within the hip joint and was followed by IVIS in real-time. There was a quantitative and qualitative difference in the bacterial load and biofilm formation between PA14 and DflgK. This difference in the ability to persist in the model between the two strains was reflected on the gait pattern and implant osseointegration.

We developed a novel uncemented hip hemiarthroplasty GN-PJI rat model. This model is clinically representative since animals can bear weight on the implant. PJI was detected by various modalities. In addition, biofilm formation correlated with implant function and stability. In conclusion, the proposed in vivo GN-PJI model will allow for more reliable testing of novel biofilm-targeting therapetics

Prosthetic joint infection (PJI) is a complex disease that causes significant damage to the peri-implant tissue. Developing an animal model that is clinically relevant in depicting this disease process is an important step towards developing novel successful therapies. In this study, we have performed a thorough histologic analysis of peri-implant tissue harvested post Staphylococcus aureus (S. aureus) infection of a cemented 3D-printed titanium hip implant in rats.

Sprague-Dawley rats underwent left hip cemented 3D-printed titanium hemiarthroplasty via posterior approach under general anesthesia. Four surgeries were performed for the control group and another four for the infected group. The hip joint was inoculated with 5×10⁹ CFU/mL of S. aureus Xen36 prior to capsule closure. The animals were scarified 3 weeks after infection. The femur was harvested and underwent micro-CT and histologic analysis. Hematoxylin and eosin (H&E), as well as Masson's trichrome (MT) stains were performed. Immunohistochemistry (IHC) using rabbit antibody for S. aureus was also used to localize bacterial presence within femur and acetabulum tissue .

The histologic analysis revealed strong resemblance to tissue changes in the clinical setting of chronic PJI. IHC demonstrated the extent of bacterial spread within the peri-implant tissue away from the site of infection. The H&E and MT stains showed 5 main features in infected bone: 1) increased PMNs, 2) fibrovascular inflammation, 3) bone necrosis, and 4) increased osteoclasts 5) fibrosis of muscular tissue and cartilage. Micro CT data showed significantly more osteolysis present around the infected prosthesis compared to control (surgery with no infection).

This is the first clinically relevant PJI animal model with detailed histologic analysis that strongly resembles the clinical tissue pathology of chronic PJI. This model can provide a better understanding of how various PJI therapies can halt or reverse peri-implant tissue damage caused by infection.

Introduction

Gram-negative prosthetic joint infections (GN-PJI) present unique challenges in management due to their distinct pathogenesis of biofilm formation on implant surfaces. The purpose of this study is to establish a clinically representative GN-PJI model that can reliably recapitulate biofilm formation on titanium implant surface in vivo. We hypothesized that biofilm formation on an implant surface will affect its ability to osseointegrate.

Aims

The aims of this study were to develop an in vivo model of periprosthetic joint infection (PJI) in cemented hip hemiarthroplasty, and to monitor infection and biofilm formation in real-time.

Aims

We present the development of a day-case total hip arthroplasty (THA) pathway in a UK National Health Service institution in conjunction with an extensive evidence-based summary of the interventions used to achieve successful day-case THA to which the protocol is founded upon.

Hip dysplasia has traditionally been classified based on the lateral centre edge angle (LCEA). A recent meta-analysis demonstrated no definite consensus and a significant heterogeneity in LCEA values used in various studies to define hip dysplasia and borderline dysplasia. To overcome the shortcomings of classifying hip dysplasia based on just LCEA, a comprehensive classification for adult acetabular dysplasia (CCAD) was proposed to classify symptomatic hips into three discrete prototypical patterns of hip instability, lateral/global, anterior, or posterior. The purpose of this study was to assess the reliability of this recently published CCAD.

One thirty four consecutive hips that underwent a PAO were categorized using a validated software (Hip2Norm) into four categories of normal, lateral/global, anterior or psosterior. Based on the prevalence of individual dysplasia and using KappaSize R package version 1.1, seventy four cases were necessary for reliability analysis: 44 dysplastic and 30 normal hips were randomly selected. Six blinded fellowship trained raters were then provided with the classification system and they looked at the x-rays (74 images) at two separate time points (minimum two weeks apart) to classify the hips using standard PACS measurements. Thereafter, a consensus meeting was held where a simplified flow diagram was devised before a third reading by four raters using a separate set of 74 radiographs took place.

Intra-rater results per surgeon between Time 1 and Time 2 showed substantial to almost perfect agreement amongst the raters. With respect to inter-rater reliability, at time 1 and time 2, there was substantial agreement overall between all surgeons (kappa of 0.619 for time 1 and 0,623 for time 2). Posterior and anterior rating categories had moderate and fair agreement at time 1 and time 2, respectively. At time 3, overall reliability (kappa of 0.687) and posterior and anterior rating improved from Time 1 and Time 2.

The comprehensive classification system provides a reliable way to identify three categories of acetabular dysplasia that are well-aligned with surgical management. The term borderline dysplasia should no longer be used.

Aims

The aim of the current study was to assess the reliability of the Ottawa classification for symptomatic acetabular dysplasia.

Aims

Calcium sulphate has traditionally been used as a filler of dead space arising during surgery. Various complications have been described following the use of Stimulan bio-absorbable calcium sulphate beads. This study is a prospective observational study to assess the safety profile of these beads when used in revision arthroplasty, comparing the complication rates with those reported in the literature.

Purpose

The purpose of this study is to compare radiographic outcomes of patients treated with dorsal spanning plates with previously reported normal values of radiographic distal radius anatomy and compare the results to prior publications for both external fixation and internal fixation with volar locked plates.

The current study aimed to determine the influence of acetabular coverage and intraarticular pathology on post-operative functional outcomes of arthroscopy for cam type FAI.

Based on 762 hip scopes performed by a single surgeon between 2013 and 2016, we excluded patients with previous surgery on the hip, mixed FAI, surgical hip dislocation, and missing outcome scores. From this, 97 hips between the ages 17 and 48 that underwent arthroscopy for cam deformity were identified for analysis. Every patient received a partial capsulotomy, cam resection and either labral repair or resection. Measurements for acetabular coverage consisted of pre-operative lateral edge angle (LCEA) (mean 30°, range: 15.4°–40°) and three-dimensional anterior and posterior acetabular coverages. Intraoperative Beck scores were acquired from operative reports, and Hip Disability and Osteoarthritis Outcome Score (HOOS) was collected pre- and post-operatively.

Significant post-operative improvement was found in scores of all categories of the HOOS (p < 0.05). However, improvement in HOOS was not correlated with the LCEA, anterior coverage, or posterior coverage. There was a trend toward lower Beck grades (1–3) resulting in better HOOS outcomes than higher Beck grades (4–5). Also, lower Beck grades showed significantly lower alpha angle (mean = 55.86) than higher grades (mean = 73.48).

We showed that cam FAI arthroscopic resection improved patient outcome, and confirmed the relationship between the Beck score and functional outcome. However, functional improvement was not related to acetabular coverage suggesting that the so-called “borderline” dysplasia is not a useful radiographic indicator for surgical management.

Periprosthetic joint infection (PJI) remains a challenging complication following Total Hip Arthroplasty (THA). It is associated with high levels of morbidity, mortality and is time consuming and expensive to treat. Our management generally relies on identification of the infecting organism(s) in order to define the appropriate treatment strategy. Patients with culture-negative PJI poses a greater challenge to surgeons and to the wider multidisciplinary team.

This study compares the outcomes of 50 consecutive complex culture-positive (deemed unsuitable for single stage exchange) and 50 culture-negative THAs managed with two-stage revision arthroplasty with a minimum of five years follow-up.

Culture-negative PJIs were associated with older age, smoking, external referral source and greater use of preoperative antibiotics. There was however no significant difference in outcome between these groups of patients with a similar complication rates and reinfection rates of 6% at 5 years.

Culture negative periprosthetic sepsis generates concern, and is often considered a poor prognostic indicator. This study suggests that a strict 2 stage protocol is associated with satisfactory outcomes in such cases.

Revision surgery for total knee replacement is a complex procedure, carrying an increased risk for the patient and cost for hospitals. As well as increased cost of peri-operative investigations, blood transfusions, surgical instrumentation, implants and theatre time, there is a well documented increased length of stay (LOS), accounting for the majority of actual costs associated with surgery.

We compared revision surgery for infection vs. other causes (aseptic loosening, dislocation, mal-alignment). Clinical, demographic and economic data were obtained for 180 consecutive revision total knee replacements performed at a tertiary referral centre between 2003 and 2012. Actual costs and National Health Service tariffs were compared per patient and mean difference calculated.

Mean age was 66 years (range 17–87) with 62 male and 117 female patients. Mean LOS for aseptic cases was 10 days (range 1–62) and 20 days (range 4–103) for infection. Mean cost difference in aseptic cases (n = 125) was £−933 (SD = £12,204), and £−3907 (SD = £7,256) for infection (n = 54).

Surgery for infection was associated with increased operating times, blood loss and complications compared to revision for aseptic causes. LOS for infection was on average double that for aseptic cases (p < 0.05). Current NHS tariffs do not fully reimburse the increased costs associated with providing a revision knee surgery service, with even greater cost incurred by the treating hospital for infected cases. These losses may negatively influence the provision of revision surgery in the NHS.

Introduction/Aim

Flexor tendon injuries of the hand are common with an incidence of over 3000 per annum in the UK. These injuries can affect hand function significantly. Early treatment with optimal repair is crucial to prevent disability.

This study aimed at investigating the re-rupture rate following primary flexor tendon repair at our institution and to identify potential risk factors for re-rupture.

Introduction

Anterior cruciate ligament (ACL) rupture is a common sporting injury, often managed surgically with patella-tendon or hamstrings autograft. Surgeons are under increasing pressure for open transparent assessment of their performance. Scoring systems can be used to assess outcome. More than 50 different scoring systems have been identified to assess the ACL deficient knee.

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.

Introduction: Clavicle fractures represent 5% of fractures in adults and almost 44% of shoulder injuries and are usually treated none operatively with good results. However significantly displaced fractures can be associated with high non-union rate and there is a lack of consensus on when surgical treatment is indicated for such fractures. The aim of this study was to identify guidelines for surgical intervention, safer surgical approach and outcome of surgical intervention.

Method: A retrospective audit of all clavicle fractures managed surgically over past 5 years (March 2004 to 2009) in a district general hospital. Case notes were reviewed to study the surgical indication, surgical approach, patient satisfaction and oxford should score and need for metal work removal.

In all 35 patients (29 male) underwent surgery for significant fracture displacement with shortening, manual workers and keen sportsmen at the time of injury. The infraclavicular approach was used in 21 patients and 14 patients had direct incision approach. Radiological union was achieved in all patients after an average of 13.26(8–24) weeks. Six patients required plate removal at 6 months following surgery, infraclavicular (2 patients) & direct approach (4 patients). All patients returned to their original occupation at average 2.55 months. The Oxford Shoulder Score at 3 months after surgery was average 15 (range12–20) and all patients, except one, scored excellent on subjective scoring.

Conclusion: Our study showed excellent surgical outcome for displaced clavicle fractures in young and active patients and is supported by the high union rate, good oxford shoulder score, early return to work and high patient satisfaction scores. The infraclaviculr approach is a betterthan direct approach based on the low complication rate and less need for metal work removal.

Clavicle fracture account for about 44% of all adult fracture around the shoulder, although non-operative care results in high union rates for most, surgery is indicated in particular if displacement and/or shortening greater than 15–20 mm, lack of cortical apposition in young, healthy, active individual to yield the best clinical results in terms of alignment, union and early mobilisation.

We did a retrospective audit to define the guidelines for admission, safer surgical approach and functional outcome using oxford score for the period Jan2002–Jan2007.

This included 35pts, with Female: male ratio 1:2.5, Right: left side of 12:23, just over 50%were manual labours. Most common indication for surgery was displacement/shortening (16pts). 28 pts were operated within 4 weeks as acute admission.

Direct incision was used in 14pts and infraclavicular incision in 21pts.

Radiological union were seen in all pts on average 13.26 weeks (8 – 24wks). 10 patients had minor complications, 28% with direct incision and 19% with infraclavicular approach 29 patients went back to original work by 2.55 month, 5 excluded as 3 were at school, 2 unemployed and 1 did not mention. All patients had an oxford score of 12–20, showing satisfactory joint function.

Metal work were removed in 6 patients, 2 (9.5%) in infraclavicular and 4 (28%) in direct incision.

Conclusion: Our study included 35 patients, union were achieved in all with good functional results. 34 patients express to recommend surgical fixation to others. Infraclavicular approach was associated with less complication and less metal work removal.