Enterococcus faecalis is a rare but recognized cause of prosthetic joint infection. It is notorious for formation of biofilm on prosthetic surfaces. We hypothesized that a ‘serum factor’ was responsible for transformation of E. faecalis from its planktonic form to a biofilm existence upon making contact with prostheses. Using a novel ‘proteomic approach’, we studied the protein expression profiles of this bacterium when grown on an artificial surface in a serum environment against a control. E.faecalis 628 transconjugant formed by conjugation clinical strain (E55) and laboratory strain (JH2-2) was used to inoculate each of rabbit serum (RS) and Brain Heart Infusion (BHI) agar as a control and grown for 24 hours. Proteins were harvested for analysis in fractions including cell surface, membrane and cytosolic proteins. Recovered proteins were separated using 2-dimentional polyacrylamide gel electrophoresis (2D PAGE). Gels were stained and spots of interest harvested. These were analyzed using MALDI mass spectrometry followed by peptide mass fingerprinting using online database searches. Two surface exclusion proteins Sea1 and PrgA were only expressed from the serum culture. These proteins are both encoded by genes very close to the gene for enterococcal aggregation substance PrgB, which plays an integral role in biofilm formation. PrgA and PrgB are both encoded by the prgQ operon and hence expressed simultaneously upon activation of the operon. This tendency for serum only protein expression suggests the possibility of a pheromone-like activator in serum that could be a potential therapeutic target for management of biofilm associated E. faecalis prosthetic infections

Introduction. The prosthetic impingement occurs if the range of motion of the hip exceeds implant mobility or in case of component malorientation. This retrieval study was designed to assess the frequency and the risk factors of this phenomenon. Material and Methods. The frequency and the severity of the impingement were calculated from a continuous series of 311 cups retrievals collected between 1989 and 2004 by a single surgeon. The reason for retrieval was loosening (131 cases), infection (43 cases), instability (56 cases), osteolysis (28 cases), unexplained pain (48 cases) and prosthetic impingent (5 cases all with hard bearings). The notching at the cup rim was assessed twice by two examiners with optic magnification. The risk factors were analyzed from clinical charts by univariate and cox multihazard. Results. Among the 311 cups explants, the frequency of impingement was 59.2% (it was severe in 11%, the notching exceeding 3 millimeters). The impingement was the reason for removal in only 1.6%, meaning that it was mainly unexpected (98.4 percent). The impingement was more frequent when revisions were performed because of instability (notching 80%), when the sum of hip motion exceeded 200 degrees (sum of motion in the 6 degrees of freedom of the hip) (notching 66%). The other risk factors were: use of heads with skirts, liner with an elevated rim, and head-neck ratio below 2, younger age at surgery. The multivariate analysis identified only two independent factors: 1) the use of skirted heads (Odd ratio 3.2 (1.2–15.3)), 2) and revision because of instability (Odd ratio 4.2 (1.1–16.2)). In contrast different classical factors were not correlated with impingement on retrieval: cup inclination, the duration before retrieval, the indication for primary prosthetic replacement. Discussion and Conclusion. This study underlines the impingement is common when assessing cup retrievals (over 50 percent). One should be aware of impingement when performing hip replacement in patients having a high range of motion. This situation may require prostheses with a high head-neck ratio, as well as use of computer-assisted surgery. One should avoid liners with elevated rim as well as heads with skirts to prevent dislocation, particularly when other risk factors are detected

Prosthetic joint infection is one of the most challenging complications of joint alloplasty and the diagnosis remains difficult. The aim of the study was to investigate the bacterial flora in surgical samples from 22 prosthetic patients using a panel of culture-independent molecular methods including broad range 16S rRNA gene PCR, cloning, sequencing, phylogeny, quantitative PCR (qPCR), and fluorescence in situ hybridization (FISH). Concomitant samples were cultured by standard methods. Molecular methods detected presence of bacteria in samples from 12 of 22 patients. Using clone libraries a total of 40 different bacterial species were identified including known pathogens and species not previously described in association with prosthetic joint infections. The predominant species were Propionibacterium acnes and Staphylococcus epidermidis; polymicrobial infections were found in 9 patients. Culture-based methods showed bacterial growth in 8 cases with the predominant species being S. epidermidis. Neither anaerobic bacteria (including P. acnes) nor any of the species not previously described in implant infections were isolated. Additionally, 7 of the 8 culture positive cases were monomicrobial. Overall, the results of culture-based and molecular methods showed concordance in 11 cases (hereof 9 negative by both methods) and discrepancy in 6 cases. In the remaining 5 cases, culture-based methods identified only one species or a group of bacteria (e.g., coagulase negative staphylococci or coryneform rods), while culture-independent molecular methods were able to detect several distinct bacterial species including a species within the group identified by culture. A qPCR assay was developed to assess the abundance of Propionibacterium while S. aureus was quantified by a published S. aureus qPCR assay. These quantifications confirmed the findings from the clone library approach and showed the potential of qPCR for fast detection of bacteria in orthopedic samples. Additionally, both single cells and microcolonies were visualized using FISH and confocal scanning laser microscopy. In conclusion, the molecular methods detected a more diverse bacterial flora in prosthetic joint infections than revealed by standard culture-based methods, and polymicrobial infections were more frequently observed. The pathogenesis of these microorganisms and their role in implant-associated infections needs to be determined

Aims. The aim of this study was to describe implant and patient-reported outcome in patients with a unilateral transfemoral amputation (TFA) treated with a bone-anchored, transcutaneous prosthesis. Methods. In this cohort study, all patients with a unilateral TFA treated with the Osseointegrated Prostheses for the Rehabilitation of Amputees (OPRA) implant system in Sahlgrenska University Hospital, Gothenburg, Sweden, between January 1999 and December 2017 were included. The cohort comprised 111 patients (78 male (70%)), with a mean age 45 years (17 to 70). The main reason for amputation was trauma in 75 (68%) and tumours in 23 (21%). Patients answered the Questionnaire for Persons with Transfemoral Amputation (Q-TFA) before treatment and at two, five, seven, ten, and 15 years’ follow-up. A prosthetic activity grade was assigned to each patient at each timepoint. All mechanical complications, defined as fracture, bending, or wear to any part of the implant system resulting in removal or change, were recorded. Results. The Q-TFA scores at two, five, seven, and ten years showed significantly more prosthetic use, better mobility, fewer problems, and an improved global situation, compared with baseline. The survival rate of the osseointegrated implant part (the fixture) was 89% and 72% after seven and 15 years, respectively. A total of 61 patients (55%) had mechanical complications (mean 3.3 (SD 5.76)), resulting in exchange of the percutaneous implant parts. There was a positive relationship between a higher activity grade and the number of mechanical complications. Conclusion. Compared with before treatment, the patient-reported outcome was significantly better and remained so over time. Although osseointegration and the ability to transfer loads over a 15-year period have been demonstrated, a large number of mechanical failures in the external implant parts were found. Since these were related to higher activity, restrictions in activity and improvements to the mechanical properties of the implant system are required. Cite this article: Bone Joint J 2020;102-B(1):55–63

Aims. Osseointegrated prosthetic limbs allow better mobility than socket-mounted prosthetics for lower limb amputees. Fractures, however, can occur in the residual limb, but they have rarely been reported. Approximately 2% to 3% of amputees with socket-mounted prostheses may fracture within five years. This is the first study which directly addresses the risks and management of periprosthetic osseointegration fractures in amputees. Methods. A retrospective review identified 518 osseointegration procedures which were undertaken in 458 patients between 2010 and 2018 for whom complete medical records were available. Potential risk factors including time since amputation, age at osseointegration, bone density, weight, uni/bilateral implantation and sex were evaluated with multiple logistic regression. The mechanism of injury, technique and implant that was used for fixation of the fracture, pre-osseointegration and post fracture mobility (assessed using the K-level) and the time that the prosthesis was worn for in hours/day were also assessed. Results. There were 22 periprosthetic fractures; they occurred exclusively in the femur: two in the femoral neck, 14 intertrochanteric and six subtrochanteric, representing 4.2% of 518 osseointegration operations and 6.3% of 347 femoral implants. The vast majority (19/22, 86.4%) occurred within 2 cm of the proximal tip of the implant and after a fall. No fractures occurred spontaneously. Fixation most commonly involved dynamic hip screws (10) and reconstruction plates (9). No osseointegration implants required removal, the K-level was not reduced after fixation of the fracture in any patient, and all retained a K-level of ≥ 2. All fractures united, 21 out of 22 patients (95.5%) wear their osseointegration-mounted prosthetic limb longer daily than when using a socket, with 18 out of 22 (81.8%) reporting using it for ≥ 16 hours daily. Regression analysis identified a 3.89-fold increased risk of fracture for females (p = 0.007) and a 1.02-fold increased risk of fracture per kg above a mean of 80.4 kg (p = 0.046). No increased risk was identified for bilateral implants (p = 0.083), time from amputation to osseointegration (p = 0.974), age at osseointegration (p = 0.331), or bone density (g/cm2, p = 0.560; T-score, p = 0.247; Z-score, p = 0.312). Conclusion. The risks and sequelae of periprosthetic fracture after press-fit osseointegration for amputation should not deter patients or clinicians from considering this procedure. Females and heavier patients are likely to have an increased risk of fracture. Age, years since amputation, and bone density do not appear influential. Cite this article: Bone Joint J 2020;102-B(2):162–169

Aims

Prior cost-effectiveness analyses on osseointegrated prosthesis for transfemoral unilateral amputees have analyzed outcomes in non-USA countries using generic quality of life instruments, which may not be appropriate when evaluating disease-specific quality of life. These prior analyses have also focused only on patients who had failed a socket-based prosthesis. The aim of the current study is to use a disease-specific quality of life instrument, which can more accurately reflect a patient’s quality of life with this condition in order to evaluate cost-effectiveness, examining both treatment-naïve and socket refractory patients.

Patients with transfemoral amputation (TFA) often experience problems related to the use of socket-suspended prostheses. The clinical development of osseointegrated percutaneous prostheses for patients with a TFA started in 1990, based on the long-term successful results of osseointegrated dental implants. Between1999 and 2007, 51 patients with 55 TFAs were consecutively enrolled in a prospective, single-centre non-randomised study and followed for two years. The indication for amputation was trauma in 33 patients (65%) and tumour in 12 (24%). A two-stage surgical procedure was used to introduce a percutaneous implant to which an external amputation prosthesis was attached. The assessment of outcome included the use of two self-report questionnaires, the Questionnaire for Persons with a Transfemoral Amputation (Q-TFA) and the Short-Form (SF)-36. The cumulative survival at two years’ follow-up was 92%. The Q-TFA showed improved prosthetic use, mobility, global situation and fewer problems (all p < 0.001). The physical function SF-36 scores were also improved (p < 0.001). Superficial infection was the most frequent complication, occurring 41 times in 28 patients (rate of infection 54.9%). Most were treated effectively with oral antibiotics. The implant was removed in four patients because of loosening (three aseptic, one infection). Osseointegrated percutaneous implants constitute a novel form of treatment for patients with TFA. The high cumulative survival rate at two years (92%) combined with enhanced prosthetic use and mobility, fewer problems and improved quality of life, supports the ‘revolutionary change’ that patients with TFA have reported following treatment with osseointegrated percutaneous prostheses. Cite this article: Bone Joint J 2014;96-B:106–13

Gram staining is used as an initial indicator of synovial joint infection but has widely varied false negative rates in the literature. Clinical decisions are often made on the basis of gram stain results, such as whether a patient requires urgent surgery, and therefore it is important to understand the tests efficacy. A retrospective review of synovial fluid aspirates in NHS Tayside for the years 2017 and 2018 was performed from the departmental microbiology database. Aspirates of large joints were included (hip, knee, shoulder, wrist, elbow, ankle). Any joints with prosthesis were excluded, including fixation metalwork. Any abscess overlying a joint that was not proven to penetrate the joint was also excluded. Initial gram stain results and formal culture results were reviewed. Final culture results were considered to be the gold standard to compare gram stain results to. 2167 samples were reviewed. Of these 1552 were excluded base on inclusion criteria. Of the remaining 615, 120 (19.5%) were culture positive. There were 33 positive gram stain results, 1 false positive and 32 true positive results. The sensitivity was 26.67% with a specificity of 99.80% (p=0.0001). The negative predictive value is 84.88% (CI 83.44% – 86.21%). These results show that gram stain tests of native joints have a low sensitivity and poor negative predictive value. This is reflected in the current literature with prosthetic joints. Based on this study caution should be used when interpreting a negative gram stain result with appropriate safety netting and follow up required alongside clinical assessment

Dual mobility significantly reduces the risk of prosthetic instability. This mechanical complication occurs when the prosthetic head moves out from the retentive polyethylene liner, such phenomenon called intra-prosthetic dislocation reports a ten-year incidence of 2% in the literature. We prospectively analysed all intra-prosthetic dislocations having occurred since 1985 in our department in order to investigate patient- and implant-related risk factors. 91 intra-prosthetic dislocations occurred with NOVAE (SERF) cups in 85 patients of mean age 50.7 years. Intra-prosthetic dislocation occurred after a mean period of 8.8 years. A PRO (SERF) stem was implanted in 56 cases and a PF (SERF) stem in 35. The stems were different from one another in their neck diameter and material: 13 mm titanium neck and 16 mm stainless steel neck respectively. When taking both prosthetic features into account, no significant difference could be established regarding the time between implantation and dislocation. Comparison between these two prosthetic features was performed by means of two continuous homogeneous series which included 240 patients implanted with PF stems and 382 patients with PRO stems. At a mean 15-year follow-up, the two series reported a non-statistically different intra-prosthetic dislocation rate of 4%. In both series, young age and large diameter cups were considered predisposing factors for intra-prosthetic dislocation. Therefore, unlike suggested by several authors, prosthetic neck material and diameter do not appear as the main predictors for intra-prosthetic dislocation which is highly promoted by patient-related features

Aims

The aim of this study was to perform the first population-based description of the epidemiological and health economic burden of fracture-related infection (FRI).

Purpose. This study compares outcomes in patients with complete congenital fibula absence treated with an amputation protocol to those using an extension prosthesis. Introduction. Complete fibula absence presents with significant lower limb deformity. Parental counselling regarding management is paramount in achieving the optimum functional outcome. Amputation offers a single surgical event with minimal complications and potential excellent functional outcome. Method. 32 patients were identified. 9 patients (2M: 7F, median age at presentation of 22yrs) utilized an extension prosthesis. 23 patients (16M: 7F, median age at presentation of 10 months) underwent 25 amputations during childhood: only two underwent tibial kyphus correction. Mobility was assessed using SIGAM and K scores. Quality of life was assessed using the PedsQL inventory questionnaire; pain by a verbal severity score. Results. 19 Syme and one Boyd amputation in 19 patients were performed early (mean age 15 months). 4 Syme and one trans-tibial amputation in 4 patients took place in older children (mean age 6.6 years). K Scores were significantly higher (mean 4 versus 2) and pain scores lower in the amputation group allowing high impact activity compared to community ambulation with an extension prosthesis. The SIGAM and PedsQL scores were all better in the amputation group, but not significantly so. Conclusion. Childhood amputation for severe limb length inequality and foot deformity in congenital fibula absence offers excellent short term functional outcome with prosthetic support. The tibial kyphus does not need routine correction and facilitates prosthetic suspension. Accommodative extension prostheses offer reasonable long term function but outcome scores are lower

Background. The decision to attempt limb salvage vs to amputate in a significant traumatic limb injury is based on patient´s best predicted outcome. When amputation cannot be avoided the aim is to provide a pain free limb whilst preserving the soft tissue and limb length. Methods. Retrospective study covering 5 years (2011–2016), all the trauma patients requiring lower limb amputation (LLA) included. Demographics, mechanism, type of injury, amputation type, cause and level, theatre trips for stump management were analysed. Results. 19 patients aged 27–93 included. RTC was the leading cause (47%) of LLA. Amputation type: traumatic, caused by the injury itself (31.5%) acute surgical, amputation performed in a limb threatening injury (37%); 72% of them had vascular compromise delayed amputations after failure of limb salvage surgery (31.5%); failed soft tissue coverage and poorly functioning limb were the lead cause (33% each) Type of injury: open fractures (89%), isolated to a limb segment (53%). One level/extended level=9/10 patients. More than 50% of initial amputations were extended with multiple subsequent theatre trips (33/10 patients) for stump management. Conclusions. It was difficult to predict the patients needing an extended amputation. Early MDT and prosthetic rehab service involvement is crucial in LLA decision. When consenting patients for LLA consider a 50% change to extend the initial level of amputation with subsequent theatre trips

Aims

It is imperative to understand the risks of operating on urgent cases during the COVID-19 (SARS-Cov-2 virus) pandemic for clinical decision-making and medical resource planning. The primary aim was to determine the mortality risk and associated variables when operating on urgent cases during the COVID-19 pandemic. The secondary objective was to assess differences in the outcome of patients treated between sites treating COVID-19 and a separate surgical site.

Most fractures of the radial head are stable undisplaced or minimally displaced partial fractures without an associated fracture of the elbow or forearm or ligament injury, where stiffness following non-operative management is the primary concern. Displaced unstable fractures of the radial head are usually associated with other fractures or ligament injuries, and restoration of radiocapitellar contact by reconstruction or prosthetic replacement of the fractured head is necessary to prevent subluxation or dislocation of the elbow and forearm. In fractures with three or fewer fragments (two articular fragments and the neck) and little or no metaphyseal comminution, open reduction and internal fixation may give good results. However, fragmented unstable fractures of the radial head are prone to early failure of fixation and nonunion when fixed. Excision of the radial head is associated with good long-term results, but in patients with instability of the elbow or forearm, prosthetic replacement is preferred. This review considers the characteristics of stable and unstable fractures of the radial head, as well as discussing the debatable aspects of management, in light of the current best evidence. Cite this article: Bone Joint J 2013;95-B:151–9

Aims

Complex fractures of the femur and tibia with associated severe soft tissue injury are often devastating for the individual. The aim of this study was to describe the two-year patient-reported outcomes of patients in a civilian population who sustained a complex fracture of the femur or tibia with a Mangled Extremity Severity Score (MESS) of ≥ 7, whereby the score ranges from 2 (lowest severity) to 11 (highest severity).

Aims

The aim of this study was to describe variation in hip fracture treatment in Norway expressed as adherence to international and national evidence-based treatment guidelines, to study factors influencing deviation from guidelines, and to analyze consequences of non-adherence.

To validate the Modified Forgotten Joint Score (MFJS) as a new patient-reported outcome measure (PROM) in hip and knee arthroplasty (THR/TKR) against the UK's gold standard Oxford Hip and Knee Scores (OHS/OKS). The MFJS is a new assessment tool devised to provide a greater discriminatory power, particularly in well performing patients. It measures an appealing concept; the ability of a patient to forget about their artificial joint in everyday life. Postal questionnaires were sent out to 400 THR and TKR patients who were 1–2 years post-op. The data collected from the 212 returned questionnaires was analysed in relation to construct and content validity. 77 patients took part in a test-retest repeatability assessment. The MFJS proved to have an increased discriminatory power in high-performing patients in comparison to the OHS and OKS, highlighted by its more normal frequency of distribution and reduced ceiling effects. 30.8% of patients (n=131) achieved excellent OHS/OKS scores of 42–48 this compared to just 7.69% of patients who achieved a proportionately equivalent MFJS score of 87.5–100. The MFJS proved to have an increased test-retest repeatability based upon its intra-class correlation coefficient of 0.97 compared to the Oxford's 0.85. The MFJS provides a more sensitive tool in the assessment of well performing hip and knee arthroplasties in comparison to the OHS/OKS. The MFJS tests the concept of awareness of a prosthetic joint, rather than pain and function and therefore should be used as adjunct to the OKS/OHS

The concept of stainless steel dual mobility cups in total hip arthroplasty has demonstrated very low long-term instability rates and a 98% survival rate after 12 years. We systematically implanted titanium alloy acetabular cups during a one year period. The purpose of our retrospective study was to report the 18-year clinical outcome data in a homogeneous and continuous series of 103 primary total hip replacements after implantation of a cementless titanium cup. All patients were implanted with NOVAE Ti (SERF) cups made of titanium alloy combined with a retentive polyethylene liner and a 22.2 mm cobalt chrome prosthetic head. Mean patient age at the time of surgery was 53 years. All patients were clinically and radiographically evaluated. The overall 18-year actuarial cup survival rate with a 95% confidence interval was 87.4%. At last follow-up, there was no evidence of implant instability whereas acetabular aseptic loosening was reported in one case and high wear of the retentive liner in 9. The results of this investigation confirmed the long-term stability of dual-mobility implants. The main limitation of this system was early wear of the polyethylene liner in contact with the titanium metal back and reaction with third body along with loss of liner retentivity. In our study, titanium demonstrated favourable osteointegration properties but poor tribologic characteristics, therefore suggesting its interest at the bone-cup interface only

Limb length disparity is a frequent complication after hip surgery inducing many surgeon-patients conflicts. To date no study has been able to precisely quantify such limb length disparity. EOS® system, currently validated to measure lower limb parameters, allows from two bi-dimensional numerical orthogonal radiographies in standing position to obtain a tri-dimensional reconstruction of lower limbs. A computerized system achieves the parameters calculation. The aim of this study is to precisely measure the limb length disparities and the other hip parameters following total hip arthroplasty surgical procedure, by using a standard X-rays and using EOS® three-dimensional reconstructions. Twenty-eight patients programmed for total hip arthroplasty have been included (i.e. thirty lower limbs). Two independent performers have carried out twice the measures either on standard X-rays and using three-dimensional reconstructions of the lower limb disparities prior and after the surgical procedure. The inter and intra-observer reproducibility for the measure of the lower limb disparities have been of the EOS® measures have been respectively of 0.854 and 0.865 and for the standard X-rays of 0.717 and 0.726. Mean length disparity observed was before Total Hip Arthroplasty of −0.328 cm (0.705; −1.266/0.530) and was of 0.088 mm (1.326; −1.635/0.632) after. We are able to decrease the lower limbs disparity in 69.1% and for the average of 0,416cm. Using EOS® system has allowed assessing with greater precision the possibility to restore equal lower limb length. This assessment has permitted introducing a new planning procedure including EOS® imaging associated to the fusion of the prosthetic tri-dimensional image in order to achieve adequate lower limb length

Introduction. The same cup orientation is classically applied to all cases of hip replacement (45° abduction, 20° anteversion). We hypothesize that this orientation must be adapted to the patient's hip range of motion. We tested this hypothesis by means of an experimental study with respect to hip range of motion, comparing the classical orientation (45° and 20°), and the orientation obtained with computer-assisted navigation. Material and Methods. The experimental model included a hemipelvis equipped with a femur whose mobility was controlled for three configurations: stiff (60°/0°, 15°/10°, 10°/10°), average (80°/10°, 35°/30°,35°/25°), mobile (130°/30°, 50°/50°, 45°/35°). The hemipelvis and the cup holder were equipped with an electromagnetic system (Fastrack ™) to measure cup orientation. The Pleos™ navigation system (equipping the hemipelvis, the femur, and the cup holder) guided the cup orientation by detecting the positions risking impingement through a kinematic study of the hip. Nine operators each performed 18 navigation-guided implantations (162 hip abduction, anteversion, and range of movement measurements) in two series scheduled 2 months apart. Results. The model used herein showed intra and interobserver reliability. Compared to the navigation-assisted surgery, the arbitrary orientation gave a mean anteversion error of only 1° ± 6° (−12 to +19°) but 5° ± 8° (−26° to +13°) for abduction. However, 16% of the errors were more than 10° in anteversion (1/2 in the mobile configuration) and 11% of the errors were more than 15° in abduction (for the most part in the mobile configuration). With arbitrary orientation, the errors consisted in excess anteversion and insufficient abduction. Discussion and Conclusion. The experimental model developed was reliable and can be used to evaluate different prosthetic configurations. This study emphasizes that the ideal arbitrary cup orientation cannot be applied to all hips. All the surgeons are very reproducible but the only way to integrate the range of motion in there ‘own way to do’ in vitro, is to use a navigation system witch can guide the surgeon so as to reduce the risk of impingement and instability