Retained polymethylmethacrylate (PMMA) debris in surgical instrument trays is a rare, but disquieting situation for the arthroplasty surgeon. Although retained debris could be considered to be sterile after autoclaving, there is no peer-reviewed literature to support this assumption. This uncertainty and subsequent fear of contamination from this bioburden often leads to operating room personnel turning over entire surgical tables and opening new surgical instruments, which consumes time and burdens a hospital's sterilization infrastructure. Consequently, the purpose of the current study was to determine if retained, heavily contaminated PMMA in surgical trays could be effectively sterilized through clinically utilized autoclave protocols. MSSA (Xen36, Perkin Elmer) biofilm was grown on identically sized PMMA (Palacos R) coupons for 72-hour duration. Following incubation, coupons were exposed to three commonly used sterilization protocols. Cobalt-Chrome (CC) coupons were included in the same tray, replicating instruments in proximity to retained PMMA. Autoclave protocols included: 1.) Single Instrument Flash protocol: Pre-vac, 270° F, 10 min exposure, 1 min drying, 2.) One Tray OR protocol: Pre-vac, 270° F, 4 min exposure, 1 min drying, and 3.) Standard Post-Operative protocol: Pre-vac, 270° F, 10 min exposure, 60 min drying. Control coupons did not undergo autoclaving. Coupons were then sonicated for 30 minutes in tryptic soy broth and plated to count CFUs. Experiments were performed in quadruplicate. Control coupons showed significant contamination with CFU counts in the range of 10. 6. CFU/mL. CFU counts of zero across all autoclaved PMMA and CC coupons revealed that each protocol was effective in completely eradicating culturable S. aureus, confirming clinical efficacy on orthopaedic cement sterilized in surgical trays. Our findings demonstrate that heavily contaminated PMMA and exposed metal in surgical trays can be effectively sterilized through several autoclaving protocols. Clinicians should feel confident in the efficacy of autoclave protocols in removing bacteria and its associated biofilm from othopaedic materials

Cutibacterium species (formerly Propionibacterium species) are increasingly recognized as causative pathogens of low-grade periprosthetic joint infections (PJI). The clinical manifestation of infections caused by this low virulent microorganism is nonspecific and the interpretation remains challenging. In this prospective cohort study from 01/2012 to 07/2017 we analyzed the clinical and diagnostic characteristics of microbiologically proven hip PJI caused by Cutibacterium species. PJI was defined by growth of Cutibacteria in ≥2 periprosthetic tissue samples or in sonication fluid of the removed implant (>50 CFU/ml) at revision surgery. If Cutibacteria grew only in synovial fluid at least one other positive microbiological specimen or non-microbiological criterion was required. We included 26 patients suffering from Cutibacterium hip PJI, among them 19 were males (73%). The majority of PJI (24, 92%) presented delayed (3–24 months) or late (>24 months) after implantation. Sinus tract was present in 4 patients (16%) and radiological implant loosening in 16 patients (62%). Among non-microbiological diagnostic tests, increased synovial fluid leukocyte count showed the highest sensitivity (82%), followed by tissue histology (71%) and serum C-reactive protein (58%). After 7 days of incubation Cutibacterium grew in synovial fluid, periprosthetic tissue and sonication fluid culture in 20%, 42% and 32%, respectively, and in 43%, 76% and 83%, respectively, after 14 days of incubation. We conclude that Cutibacterium PJI was diagnosed late in the disease course and presented with subtle clinical signs. Prolonged culture incubation and implant sonication improved the poor performance of conventional microbiological tests. Due to lack of reliable diagnostic tests, Cutibacterium remains difficult to detect making the diagnosis challenging

Literature debates whether fluid aspirates for suspected PJI should undergo prolonged incubation for cultures. We looked at sensitivity and specificity of 14-day cultures, compared to 7-days, for aspirates from prosthetic hips and knees. Design and methods. Conducted at a quaternary referral centre for PJIs from Jan 2017 to July 2019. Suspected PJIs who underwent aspiration, incubated 14 days and later surgical intervention with minimum three tissue samples were included. Results. 176 aspirates were included. This is an increased number compared to our historic figures (average 88 Vs 48 pts/yr). 47 patients had fluid and tissue positive (true positive), 20 fluid +ive but tissue -ive (false positive), 98 fluid and tissue -ive (true negative) and 15 fluid negative but tissue +ive (False negative). Thus, sensitivity 76%, specificity 83%, positive predictive value70% and negative predictive value 87%. Of 88 positive aspirates, only 75% were within 7-day cultures. Low virulence organisms as Propionibacterium acnes and coagulase negative staph were grown later. Of 48 with only one tissue sample positive, 38 were culture-negative on aspiration and 6 grew different organisms on aspirate and tissues. Also, as many were cultured later, it suggests contamination. Conclusion. Increased numbers reflect quaternary referral nature of institution and increasing PJI load. Modest drop in sensitivity and specificity of 14-day cultures compared to 7-day(84 and 85% respectively) is due to higher false negatives. Contamination contributes to false-ive as more tissue samples become positive (there were 1076 tissue samples due to multiple sampling Vs 176 aspirates). Higher tissue yield may also be because they are more representative. Effect of antibiotic use between samples cannot be determined. Organism profile suggest14-day culture produces more contaminant growth despite a well-equipped microbiology lab with laminar airflow for subcultures. Caution in interpreting 14-day results in diagnosis of PJI of Hip and Knee is advised

Aims

Developmental dysplasia of the hip (DDH) is a complex musculoskeletal disease that occurs mostly in children. This study aimed to investigate the molecular changes in the hip joint capsule of patients with DDH.

Aims

Current treatments of prosthetic joint infection (PJI) are minimally effective against Staphylococcus aureus biofilm. A murine PJI model of debridement, antibiotics, and implant retention (DAIR) was used to test the hypothesis that PlySs2, a bacteriophage-derived lysin, can target S. aureus biofilm and address the unique challenges presented in this periprosthetic environment.

Aims

There are reports of a marked increase in perioperative mortality in patients admitted to hospital with a fractured hip during the COVID-19 pandemic in the UK, USA, Spain, and Italy. Our study aims to describe the risk of mortality among patients with a fractured neck of femur in England during the early stages of the COVID-19 pandemic.

Aims

During the COVID-19 pandemic, many patients continue to require urgent surgery for hip fractures. However, the impact of COVID-19 on perioperative outcomes in these high-risk patients remains unknown. The objectives of this study were to establish the effects of COVID-19 on perioperative morbidity and mortality, and determine any risk factors for increased mortality in patients with COVID-19 undergoing hip fracture surgery.

Aims

Of growing concern in arthroplasty is the emergence of atypical infections, particularly Cutibacterium (formerly Propionibacterium) sp. infections. Currently, the dermal colonization rate of Cutibacterium about the hip is unknown. Therefore, the aim of this study was to investigate colonization rates of Cutibacterium sp. at locations approximating anterior and posterolateral approaches to the hip joint.

Aims

Early evidence has emerged suggesting that ceramic-on-ceramic articulations induce a different tissue reaction to ceramic-on-polyethylene and metal-on-metal bearings. Therefore, the aim of this study was to investigate the tissue reaction and cellular response to ceramic total hip arthroplasty (THA) materials in vitro, as well as the tissue reaction in capsular tissue after revision surgery of ceramic-on-ceramic THAs.

Objectives

The injured anterior cruciate ligament (ACL) is thought to exhibit an impaired healing response, and attempts at surgical repair have not been successful. Connective tissue growth factor (CTGF) is reported to be associated with wound healing, probably through transforming growth factor beta 1 (TGF-β1).

Aims

We present a case series of ten metal-on-polyethylene total hip arthroplasties (MoP THAs) with delayed dislocation associated with unrecognised adverse local tissue reaction due to corrosion at the trunnion and pseudotumour formation.

In this study of 41 patients, we used proteomic, Western blot and immunohistochemical analyses to show that several reactive oxygen species scavenging enzymes are expressed differentially in patients with primary osteoarthritis and those with non-loosening and aseptic loosening after total hip replacement (THR). The patients were grouped as A (n = 16, primary THR), B (n = 10, fixed THR but requiring revision for polyethylene wear) and C (n = 15, requiring revision due to aseptic loosening) to verify the involvement of the identified targets in aseptic loosening. When compared with Groups A and B, Group C patients exhibited significant up-regulation of transthyretin and superoxide dismutase 3, but down-regulation of glutathione peroxidase 2 in their hip synovial fluids. Also, higher levels of superoxide dismutase 2 and peroxiredoxin 2, but not superoxide dismutase 1, catalase and glutathione perioxidase 1, were consistently detected in the hip capsules of Group C patients.

We propose that dysregulated reactive oxygen species-related enzymes may play an important role in the pathogenesis and progression of aseptic loosening after THR.

Infection of a total hip replacement (THR) requires component removal and thorough local debridement. Usually, long-term antibiotic treatment in conjunction with a two-stage revision is required. This may take several months. One-stage revision using antibiotic-loaded cement has not gained widespread use, although the clinical and economic advantages are obvious. Allograft bone may be impregnated with high levels of antibiotics, and in revision of infected THR, act as a carrier providing a sustained high local concentration.

We performed 37 one-stage revision of infected THRs, without the use of cement. There were three hips which required further revision because of recurrent infection, the remaining 34 hips (92%) stayed free from infection and stable at a mean follow-up of 4.4 years (2 to 8). No adverse effects were identified. Incorporation of bone graft was comparable with unimpregnated grafts.

Antibiotic-impregnated allograft bone may enable reconstruction of bone stock, insertion of an uncemented implant and control of infection in a single operation in revision THR for infection.