Aim. Pre-operative distinction between prosthetic joint infections (PJI) and non-infectious causes of joint failure is particularly challenging, especially in chronic situations. Guidelines propose different algorithms using numerous preoperative tests. We evaluated place of serology. Method. During a 9 month period, we included consecutive patients undergoing arthroplasty revision for a suspected chronic hip or knee infection. Serologies were sampled at the same day than the other blood tests. Results were compared with the final diagnosis, determined with peroperative bacteriological and histological results. Serology was performed using a multiplex antibody detection*. This multiplex antibody detection assay detects antibodies against Staphylococcus species, Propionibacterium acnes and Streptococcus agalactiae. Results. A total of 52 patients were enrolled. Median time from last arthroplasty was 30 months (extremes 8 months − 17 years). Median clinical signs duration was 6 months (extremes 1 – 40 months). Median CRP value was 6 mg/l (extremes 2 – 150) and sedimentation rate 12 mm (extremes 2 – 82). Diagnostic of PJI was finally retained for 17 patients and ruled out for 35. It was Staphylococcus aureus 3 times, coagulase negative staphylococci (CoNS) 5 times, P. acnes 4 times, candida sp. 2 times, Streptococcus agalactiae one time, Enterobacter cloacae one time and undetermined one time. Serology was concordant and accurate with the final diagnosis for 38 patients (27 sterile and 11 infected). For 7 of them, serology was the key parameter. In these cases, a CoNS or a P. acnes was isolated per-operatively on a single culture, out of 5 samples. Serology allowed confirming a contamination in 5 cases; and in 2 cases, even if not fulfilling the definition, it determined a PJI. In this study, serology had a global sensitivity of 65%, 77% specificity, 58% positive predictive value, and 82% negative predictive value. Serology reached 89% sensitivity with unchanged specificity in the subgroup of 11 patients with a CRP > 10 mg/l. Conclusions. We evaluated place of serology in the most complex cases of suspected chronic PJIs, with finally, only 33% cases with an infection. Modest results of serology can be explained because antigens included in the assay were not those expressed in sessile bacteria. And by persistence of a humoral response, witnesses of past infections, for patients who had past surgeries on the joint. However, simple and practical, when combined with all other parameters, serology could provide a valuable support in preoperative evaluation of chronic PJIs. * BJI InoplexTM

Aims. Post-traumatic osteoarthritis (PTOA) is a subset of osteoarthritis (OA). The gut microbiome is shown to be involved in OA. However, the effect of exercise on gut microbiome in PTOA remains elusive. Methods. A total of 18 eight-week Sprague-Dawley rats were assigned into three groups: Sham/sedentary (Sham/Sed), PTOA/sedentary (PTOA/Sed), and PTOA/treadmill-walking (PTOA/TW). PTOA model was induced by transection of the anterior cruciate ligament (ACLT) and the destabilization of the medial meniscus (DMM). Treadmill-walking (15 m/min, 30 min/d, five days/week for eight weeks) was employed in the PTOA/TW group. The response of cartilage, subchondral bone, serology, and gut microbiome and their correlations were assessed. Results. Eight-week treadmill-walking was effective at maintaining the integrity of cartilage-subchondral bone unit and reducing the elevated systematic inflammation factors and microbiome-derived metabolites. Furthermore, 16S ribosomal ribonucleic acid (rRNA) sequencing showed disease-relevant microbial shifts in PTOA animals, characterized by the decreased abundance of phylum TM7 and the increase of phylum Fusobacteria. At the genus level, the abundance of Lactobacillus, Turicibacter, Adlercreutzia, and Cetobacterium were increased in the PTOA animals, while the increase of Adlercreutzia and Cetobacterium was weakened as a response to exercise. The correlation analysis showed that genus Lactobacillus and Adlercreutzia were correlated to the structural OA phenotypes, while phylum Fusobacteria and genus Cetobacterium may contribute to the effects of exercise on the diminishment of serological inflammatory factors. Conclusion. Exercise is effective at maintaining the integrity of cartilage-subchondral bone unit, and the exercise-induced modification of disease-relevant microbial shifts is potentially involved in the mechanisms of exercise-induced amelioration of PTOA. Cite this article: Bone Joint Res 2022;11(4):214–225

Aims

To investigate the optimal thresholds and diagnostic efficacy of commonly used serological and synovial fluid detection indexes for diagnosing periprosthetic joint infection (PJI) in patients who have rheumatoid arthritis (RA).

Introduction and Aims: To confirm whether bacteria were present in disc material harvested at the time of discectomy; and to determine whether the presence of bacteria correlated with elevation of Anti Lipid S antibody levels; and to compare these results with antibody levels and disc specimens from patients undergoing surgery for indications other than radiculitis. We have previously demonstrated significantly elevated IgG titres (ELISA) to a glycolipid antigen found in the cell wall of most gram-positive bacteria in patients with discogenic sciatica. This raised the possibility that the inflammation associated with disc protrusion might be initiated or accelerated by bacteria. Method: A prospective study was performed using disc material harvested with stringent aseptic precautions from 207 microdiscectomy and 27 trauma, tumor or scoliosis patients (controls). Serology was obtained for all patients. Results: In the Microdiscectomy group 76/207 (37%) had positive cultures after seven days incubation, of which 26 (34%) had positive serology. Forty-nine patients had Propionibacteria, 11 Coagulase-negative-Staphylococci (CNS), eight Propionibacteria and CNS, four other organisms and four mixed growth. One hundred and thirty one (63%) patients had negative cultures of whom 15% had positive serology. There was a significant difference between patients with positive serology and culture, compared with those with negative serology and culture (Fischer exact test P< 0.01). In some patients, organisms were visible on microscopy prior to culture. Two of the patients undergoing surgery for other indications had positive cultures (P.acnes) of whom one had positive serology. Of those with negative cultures, six had positive serology. There was a significant difference between positive cultures in those with sciatica and controls (P< .001). Conclusion: A significant proportion of patients with discogenic radiculitis have positive cultures with low-virulence Gram-positive organisms (predominantly Propionibacteria ) and in proportion, a corresponding appropriate antibody response

Introduction: We have previously demonstrated significantly elevated IgG titres (ELISA) to a glycolipid antigen found in the cell wall of most gram positive bacteria in patients with discogenic radiculitis (sciatica). This raised the possibility that the inflammation associated with disc protrusion might be initiated or accelerated by the presence of bacteria. Aim of the study: To confirm whether bacteria were present in the disc material harvested at the time of discectomy. To determine whether the presence of bacteria correlated with elevation of Anti Lipid S antibody levels. To compare these results with Antibody levels and disc specimens from patients undergoing surgery for indications other than radiculitis. Methods: This was a prospective study. Recognising the frequency of contamination in clean wound culture stringent aseptic precautions were taken. Disc material was harvested from 108 microdiscectomy patients with sciatica. Disc material was also obtained from 11 patients undergoing discectomy for other indications (trauma, tumour scoliosis). Serology was obtained for all these patients. Results: In the microdiscectomy group 50/112 (45%) had positive cultures after seven days incubation, of which 15 (30%) had positive serology. Thirty-one patients had Propionibacteria, nine Coagulase negative Staphylococci (CNS), six Propionibacteria and CNS, one Corynebacterium and three mixed growth. Sixty-two (55%) patients had negative cultures and all except one had negative serology. There was a significant difference between patients with positive serology and culture compared with those with negative serology and culture (Fischer exact test P< 0.01). In some patients organisms were visible on microscopy prior to culture. Thirteen of those with postive cultures and 25 of those with negative cultures had had one or more epidural injections prior to surgery. Epidural injection was not found to be significantly associated with postive culture. None of the patients undergoing surgery for other indications had positive serology or positive cultures. Conclusion: A significant proportion of patients with discogenic radiculitis have positive cultures with low virulence Gram positive organisms (predominantly Propionibacteria) and in a proportion a corresponding appropriate antibody response

Introduction: We have previously demonstrated significantly elevated IgG titres (ELISA) to a glycolipid antigen found in the cell wall of most gram positive bacteria in patients with discogenic radiculitis (sciatica). This raised the possibility that the inflammation associated with disc protrusion might be initiated or accelerated by the presence of bacteria. Aim of the Study: To confirm whether bacteria were present in disc material harvested at the time of discectomy. To determine whether the presence of bacteria correlated with elevation of Anti Lipid S antibody levels. To compare these results with Antibody levels and disc specimens from patients undergoing surgery for indications other than radiculitis. Methods: This was a prospective study. Recognising the frequency of contamination in clean wound culture, stringent aseptic precautions were taken. Disc material was harvested from 62 microdiscectomy patients with sciatica. Disc material was also obtained from three patients undergoing decompression but without radiculitis and from three patients undergoing anterior correction of scoliosis. Serology was obtained for all these patients. Results: In the Microdiscectomy group, 27/62 (43%) had positive cultures after seven days incubation, of which nine (33%) had positive serology. 22 patients had Propionibacteria, three Coagulase negative Staphylococci, one Corynebacterium and one mixed growth. Thirty five (56.4%) patients had negative cultures and all except one had negative serology. There was a significant difference between patients with positive serology and culture compared with those with negative serology and culture (Fischer exact test P< 0.001). In some patients organisms were visible on microscopy prior to culture. Ten of those with positive cultures and fourteen of those with negative cultures had had one or more epidural injections prior to surgery. Epidural injection was not found to be significantly associated with positive culture. None of the patients undergoing surgery for other indications had positive serology or positive cultures. Conclusion: A significant proportion of patients with discogenic radiculitis have positive cultures with low virulence Gram positive organisms (predominantly Propionibacteria) and in a proportion, a corresponding appropriate antibody response

Background. Revision total knee arthroplasty (rTKA) is a complex procedure with increased risk of blood loss and transfusions. The Musculoskeletal Infection Society has included D-dimer as a serology marker for peri-prosthetic infection. The study's intent is to understand the impact of preoperative D-dimer levels on blood loss and venous thromboembolism in revision TKA. Methods. Following IRB approval, rTKA performed by a single surgeon between January 1, 2017 and December 31, 2019 were reviewed. Inclusion criteria consisted of pre-operative D-Dimer, cemented revision TKA of one or both components under tourniquet control. 89 patients met the criteria including 37 males (41.6%) and 52 females (58.4%). Mean ages were 65 for males and 67 for females. The data revealed 54 patients (61%) had an elevated D-dimer (group 1) and 35 patients (39%) had a normal D-dimer (group 2). Sex stratification showed 21 males (57.8%) and 33 females (63.5%) with elevated D-dimer. TXA protocol included 2 grams intravenous (82 patients) or 2 grams intra-articular application (7 patients). Post-operative anticoagulation included Lovenox 40mg daily for 2 weeks followed by aspirin 325 twice daily for 4 weeks. Pre-operative and post-operative hemoglobin, transfusion rates and post-operative VTE within 90 days of surgery were recorded. Results. The mean pre-operative hemoglobin (hgb) was 13.30 and post-operative was 11.21. The mean change in hgb for males was 2.75 and for females 1.91. Both male and female cohorts had an acceptable range and the change in hgb was not statistically significant (p=0.076). Two female patients (2.25%) were transfused, both receiving IV TXA and their pre-operative hgb was lower than the cohort. No VTE events were identified in either groups of patients within the 90 day post-operative period. Conclusion. This study revealed that TXA is effective in reducing blood loss following rTKA and an elevated D-dimer is not a contraindication to its use

Purpose of the study: Echinococcosis is an anthropozoonosis with a predominantly muscular, more rarely osteoarticular, localisation. The purpose of this work was to describe the conditions of discovery, the diagnostic management, the serology and pathology findings, and the results of surgical treatment as well as potential complications. Material and methods: We collected over a 16-year period, 14 cysts in eight women and six men. Mean age was 39 years (range 17–75) and delay to consultation was 36 months. The patients had an ultrasound (all 14 cases), computed tomography (n=7), MRI (n=7), hydatid serology (n=9) and pathology examination (n=10). All patients were treated surgically (7 complete resection); one patient was given associated medical treatment for a multiple localisation. Results: Muscle hydatisosis occurred in all cases as a medium-sized tumour (mean 9 cm, range 5–16 cm) which was painful in half of the cases. One cyst was superinfected and one patient had a neurological complication. The most common site was the adductor compartment of the thigh (5 cases). Four patients had an associated visceral localization. At mean 4 years follow-up, one patient had a superinfection and two others recurrence at 7 and 10 months, with surgical revision and good outcome. Discussion: The risk vascularisation of the thigh muscles explains these localisations. Ultrasound is a sensitive exploration which suggests the diagnosis in all cases. CT and MRI confirm the diagnosis and define the cyst relations. Pathology is needed for formal diagnosis. Total pericystectomy or wide resection is the best surgical technique, although not always readily achieved. Conclusion: Muscle hydatidosis is rare. Treatment is surgical, different from the osteoarticular localisation, similar to the visceral foci. Recurrence is exceptional. Prevention remains the best treatment

Femoral head allograft bone used in complex orthopaedic surgery may transmit infection from donor to recipient. In order to minimise the risk all donors are serologically screened for Hepatitis B and C, HIV, HTLV, and syphilis at the time of donation and again at 6 months post-donation. Culture swabs are taken from the acetabulum and femoral head for 48 hour anaerobic and aerobic culture, and a sample of bone is incubated for 5 days in enrichment broth culture. We have audited the culture results and screening tests performed in our bone bank from 2000 to 2005 inclusive. 1,528 allografts were received of which we had to discard 52 (3.4%) because of either positive cultures or serology. The vast majority of the positive cultures were due to S. epidermidis (30/43). All cultures were bacteria one might expect to find as normal skin flora. 3 patients had positive hepatitis C serology and 6 were syphilis EIA positive. In May 2004 we decided in line with National Transfusion Guidelines for blood donation, to exclude donors who had had a blood transfusion since 1980 to mini-mise the risk of transmission of CJD. This and the opening of an Independent Treatment Centre (ITC) in our area drastically limited the number of possible donors to our bone bank. There was a significant reduction in the number of femoral heads received in 2004 and 2005 when compared with years 2000-2003 (p = < 0.00001). We conclude that negligible numbers of femoral head allografts are lost due to our serological and microbio-logical screening tests. However measures introduced to limit the theoretical transmission of CJD via a bone allograft and the opening of a local ITC have had a huge impact on the number of potential donors available to us. To date the CJD prion has not been isolated from bone, but there have been 3 reported cases of transmission of infection by blood transfusion. We fear that the imminent introduction of a serological test for CJD will limit the number of possible bone donors even further

Aims

The aims of this study were to determine the incidence and factors for developing periprosthetic joint infection (PJI) following hemiarthroplasty (HA) for hip fracture, and to evaluate treatment outcome and identify factors associated with treatment outcome.

Aim. In an earlier study we identified severe Vitamin D deficiency as a problem in institutionalised children with cerebral palsy (CP), which resulted in rickets and a high incidence of fractures. The purpose of this study was to establish whether a cohort of non-ambulatory children with CP, living at home, presented with Vitamin D deficiency. Method. The participants were a consecutive sample (N=100) of non-ambulatory children with CP attending a CP outpatient clinic. Their ages ranged from 2 to 15 years (mean 5.8, SD 3.3 years). There were 57 males and 43 females. Nineteen were on Level IV of the Gross Motor Function Classification System (GMFCS), and 81 were on Level V. 66% were on anticonvulsant therapy (ACT). Basic demographic data was collected, and measurements included blood sample analysis and wrist radiographs. There was radiographic evidence of osteopenia and delayed ossification of the carpal bones. Results. Three participants had Vitamin D deficiency rickets confirmed by wrist changes and serology. There was a significantly higher level of Alkaline Phosphatase (p=0.04) in children on ACT than in those who did not receive ACT. Preliminary results show that one third of the children had Vitamin D deficiency. Conclusion. Non ambulatory children with CP are at risk of developing rickets. We recommend regular exposure to sunlight or Vitamin D supplementation as preventative measures. NO DISCLOSURES

Osteomyelitis is usually related to trauma, surgery, immunocompromised patients, IV drug abuse, poor vascular supply, diabetes, sickle cell disease or peripheral neuropathy. We report an unusual case of femur osteomyelitis without any of these risk factors. A 31 years old male, light smoker, presented at the Emergency Room for pain in the left thigh for about a month, without any previous event. He had 2 previous visits to the hospital with similar diffuse complaints interpreted as irradiated low back pain. He was pale, feverish but no signs of local inflamation. His left knee ROM was 30°-15°-0°. He had no neurologic deficits. Blood tests showed high WBC count and PCR (400mg/L). After contrasted CT showing an 1,2×6×2,5cm abcess the patient was taken to the OR for irrigation and debridment. The day after the patient did a MRI that showed extended femur osteomyelitis and adjacent myositis (images). He underwent new surgery for a more extensive irrigation and debridment, femur medular canal included, from where a large pus quantity erupted. The hemocultures and bone biopsys, revealed a Multissensible Strep. Alfa-hemolitic (S. anginosus) and appropriate antibiotherapy was implemented (Amoxicillin/Clavulanate). He slowed improve till 11th day when he showed rise of PCR and a new MRI showed the same inflammatory process. He underwent new surgery but no pus was visible. He gradually improved, started hyperbaric oxygen therapy and was discharged on the 28th day after the first surgery, continuing antibiotherapy at home for a total of 8 weeks. Transthoracic Ecography was normal, as well Brucella, HIV, and other serologies. Three weeks later, the patient again presented to the ER with fever and rise of inflammatory markers in blood, consistent with recurrence of the infection. The patient was taken to the OR for surgical debdridment and irrigation, but this time the cultures showed a multissensible Gemella haemolysans, possible contamination during the hyperbaric oxygen therapy sessions. This is the case of a healthy young adult with an idiopathic femur osteomyelitis, initially misinterpreted for irradiated low back pain, that recurred after the first medical and surgical successful treatment, with an unusual agent

Purpose. Severe osteo-articular infection can be a devastating disease causing local complications, multiple organ failure and death. The aim of this study is to highlight the potential severity and subsequent sequelae of osteo-articular infections in children and to determine causative factors leading to this devastating condition. Methods. We retrospectively report on six cases treated at two academic hospitals. We included all patients with osteo-articular infections who had multi-organ involvement. All patients had more than one joint as well as another organ involved as a direct result of the bacteraemia. All patients with single organ involvement were excluded. The patient files were recorded as part of a previously published study. Data capture included X-rays, serology for blood culture, FBC, ESR, CRP and HIV. Ultrasound of involved joints, technetium bone scans, echocardiograms and computed tomography of the brain were performed when indicated. Results. There was a delay in the diagnosis and subsequent treatment of all of these patients, mean duration 4.8 days(1 to 10) Twenty-two osteo-articular sites were involved mean 3,7 sites (2 to 6)and seventeen other organs mean 2,8 (2 to 5). The mean number of debridements or joint washouts for each patient was 4,5 (3 to 6). Four of the six cases cultured organisms: One Staphylococcus aureus, one Haemophilus influenzae and one Candida spp on tissue. Local complications included chronic osteomyelitis, physeal separation, pathological fractures and hip dislocation. There was one death in a nine year old HIV positive patient with severe multiple organ failure. Conclusion. A delay in the diagnosis and treatment of osteo-articular infection was identified as the causative factor leading to severe infection with life threatening complications. NO DISCLOSURES

Introduction. The treatment of chronic osteomyelitis involves a debridement of affected non-viable tissue and the use of antibiotics. Where surgery leaves a cavity, dead space management is practised with antibiotic impregnated cement. These depots of local antibiotics are variable in elution properties and need removal. We review the use of bioabsorbable synthetic calcium sulphate as a carrier of gentamicin and as an adjunct in treating intramedullary osteomyelitis. Methods. A retrospective review of cases treated consecutively from 2006 to 2010 was undertaken. Variables recorded included aetiology, previous interventions, diagnostic criteria, radiological features, serology and microbiology. The Cierney-Mader system was used to classify. Treatment involved removal of implants (if any), intramedullary debridement and local resection (if needed), lavage and instillation of the gentamicin carrier, supplemented with systemic antibiotics. Follow-up involved a survival analysis to time to recurrence, clinical and functional assessment (AOFAS-Ankle/IOWA knee/Oxford Hip) and general health outcome (SF36). Results. There were 31 patients (22 male, 9 female). The mean age was 47 years (20–67). Twenty-five cases were post-surgery (6 open fractures) and 6 were haematogenous in origin. The median duration of osteomyelitis was 1.6yrs. The bones affected were 42% femur, 45% tibia, 3% radius and 10% humerus. 11 cases had diffuse as well as intramedullary involvement. 9 cases underwent segment resection and bone transport. We identified Staph. Aureus in 16 and Coag. Neg. Staph. in 6 cases. The median follow-up was 1.7 years (0.5–5.6). The median scores attained were: AOFAS-78, DASH-32, IOWA-71, Oxford-32. There were two recurrences. Discussion. Dead space management of intramedullary infections is difficult. We describe a method for delivery of local antibiotics and provide early evidence to its efficacy. The treatment success to date is 93%. Conclusion. Bioabsorbable carriers of antibiotics are efficacious adjuncts to surgical treatment of intramedullary osteomyelitis

The treatment of chronic osteomyelitis involves a debridement of affected non-viable tissue and the use of antibiotics. Where surgery leaves a cavity, dead space management is practised with antibiotic impregnated cement. These depots of local antibiotics are variable in elution properties and need removal. We review the use of bioabsorbable synthetic calcium sulphate as a carrier of gentamicin and as an adjunct in treating intramedullary osteomyelitis. A retrospective review of cases treated consecutively from 2006 to 2010 in the Royal Liverpool University Hospital was undertaken. Variables recorded included aetiology, previous interventions, diagnostic criteria, radiological features, serology and microbiology. The Cierney-Mader system was used to classify. Treatment involved removal of implants (if any), intramedullary debridement and local resection (if needed), lavage and instillation of the gentamicin carrier, supplemented with systemic antibiotics. Follow-up involved a survival analysis to time to recurrence, clinical and functional assessment (AOFAS-Ankle/IOWA knee/Oxford Hip) and general health outcome (SF36). There were 31 patients (22 male, 9 female). The mean age was 47 years (20-67). Twenty-five cases were post-surgery (6 open fractures) and 6 were haematogenous in origin. The median duration of osteomyelitis was 1.6yrs. The bones affected were 42% femur, 45% tibia, 3% radius and 10% humerus. 11 cases had diffuse as well as intramedullary involvement. 9 cases underwent segment resection and bone transport. We identified Staphylococcus Aureus in 16 and Coagulase Negative Staphylococcus in 6 cases. The median follow-up was 1.7 years (0.5-5.6). The median scores attained were: AOFAS-78, DASH-32, IOWA-71, Oxford-32. There were two recurrences. Dead space management of intramedullary infections is difficult. We describe a method for delivery of local antibiotics and provide early evidence to its efficacy. The treatment success to date is 93%. Bioabsorbable carriers of antibiotics are efficacious adjuncts to surgical treatment of intramedullary osteomyelitis

The COVID-19 pandemic has led to unprecedented times worldwide. From lockdowns to masks now being part of our everyday routine, to the halting of elective surgeries, the virus has touched everyone and every part of our personal and professional lives. Perhaps, now more than ever, our ability to adapt, change and persevere is critical to our survival. This year's closed meeting of The Knee Society demonstrated exactly those characteristics. When it became evident that an in-person meeting would not be feasible, The Knee Society leadership, under the direction of President John Callaghan, MD and Program Chair Craig Della Valle, MD created a unique and engaging meeting held on September 10–12, 2020. Special recognition should be given to Olga Foley and Cynthia Garcia at The Knee Society for their flexibility and creativeness in putting together a world-class flawless virtual program. The Bone & Joint Journal is very pleased to partner with The Knee Society to once again publish the proceedings of the closed meeting of the Knee Society. The Knee Society is a United States based society of highly selected members who have shown leadership in education and research in knee surgery. It invites up to 15% international members; this includes some of the key opinion leaders in knee surgery from outside the USA. Each year, the top research papers from The Knee Society meeting will be published and made available to the wider orthopaedic community in The Bone & Joint Journal. The first such proceedings were published in BJJ in 2019. International dissemination should help to fulfil the mission and vision of the Knee Society of advancing the care of patients with knee disorders through leadership, education and research. The quality of dissemination that The Bone & Joint Journal provides should enhance the profile of this work and allow a larger body of surgeons, associated healthcare professionals and patients to benefit from the expertise of the members of The Knee Society. The meeting is one of the highlights of the annual academic calendar for knee surgeons. With nearly every member in attendance virtually throughout the 3 days, the top research papers from the membership were presented and discussed in a virtual format that allowed for lively interaction and discussion. There are 75 abstracts presented. More selective proceedings with full papers will be available after a robust peer review process in 2021, both online and in The Bone & Joint Journal. The meeting commenced with the first group of scientific papers focused on Periprosthetic Joint Infection. Dr Berry and colleagues from the Mayo Clinic further help to clarify the issue of serology and aspirate results to diagnose TKA PJI in the acute postoperative setting. 177 TKA's had an aspiration within 12 weeks and 22 were proven to have PJI. Their results demonstrated that acute PJI after TKA should be suspected within 6 weeks if CRP is ≥81 mg/L, synovial WBCs are ≥8500 cells/μL, and/or synovial neutrophils≥86%. Between 6– 12 weeks, concerning thresholds include a CRP ≥ 32 mg/L, synovial WBC ≥7450, and synovial neutrophils ≥ 84%. While historically the results of a DAIR procedure for PJI have been variable, Tom Fehring's study showed promise with the local delivery of vancomycin through the Intraosseous route improved early results. New member Simon Young contrasted the efficacy of the DAIR procedure when comparing early infections to late acute hematogenous PJI. DAIR failed in 63% of late hematogenous PJIs (implant age>1 year) compared to 36% of early (<1year) PJIs. Dr Masri demonstrated in a small group of patients that those with well-functioning articulating spacers can retain their spacers for over 12 months with no difference in infection from those that had a formal two stage exchange. The mental toll of PJI was demonstrated in a longitudinal study by Doug Dennis, where patient being treated with 2 stage exchange had 4x higher rates of depression compared to patient undergoing aseptic revision. The second session focused on both postoperative issues with regards to anticoagulation and manipulation. Steven Haas demonstrated high complication rates with utilization of anticoagulation for treatment of postoperative pulmonary embolism with modern therapeutic anticoagulation (warfarin, enoxaparin, Xa inhibitors) with the Xa inhibitors demonstrating lower complication rates. Two papers focused on the topic of manipulation. Mark Pagnano presented data on timing of manipulation under anesthesia up to even past 12 months. While gains were modest, a subset of patients did achieve substantial gains in ROM > 20degrees even after 3 months post op. Dr Westrich's study demonstrated no difference in MUA outcomes with either IV sedation or neuraxial anesthesia although the length of stay was shorter in the IV sedation group. Several studies in Session II focused on kinematics and femoral component position. Dr Li's in vivo kinematic study during weightbearing flexion and gait demonstrated that several knees rotated with a lateral pivot motion and not all knees can be described with a single motion character. Dr Mayman and his group utilized a computational knee model to demonstrate that additional distal femoral resection results in increasing levels of mid -flexion instability and cautioned against the use of additional bony resection as the first line for flexion contractures. Using computer navigation, Dr Huddleston's study nicely outlined the variability in femoral component rotation to achieve a rectangular flexion gap utilizing a gap balanced method. The third session opened the meeting on Friday morning. The focus was on unicompartmental knee arthroplasty and the increasing utilization of robotic assisted total knee arthroplasty. David Murray showed using registry data that for patient with higher comorbidities (ASA >3), UKA was safer and more cost effective than TKA while Dr Della Valle's group demonstrated overall lower average healthcare costs in UKA patients compared to TKA in the first 10 years after surgery. Dr Geller assessed UKA survivorship among 3 international registries. While survivorship varied by nation and designs, certain designs consistently had better overall performance. Dr Nunley and his group showed robotic navigation UKA significantly reduced outliers in alignment and overhang compared to manual UKA. Dr Catani's data demonstrated that full thickness cartilage loss should still be considered a requirement for UKA success even with robotic assistance. Despite a high dislocation rate of 4%, Mr Dodd demonstrated high survivorship for lateral UKA despite historical contraindications. The growing evidence for robotics TKA was demonstrated in two studies. Professor Haddad showed less soft tissue injury, reduced bone trauma and improved accuracy or rTKA compared to manual TKA while Dr Gustke single surgeon study showed his rTKA had improved forgotten joint scores and less ligament releasing required for balancing. Despite these finding, Dr Lee's study demonstrated that a robotic TKA could not guarantee excellent pain relief and other factors such a patient expectations and psychological factors play a role. Our fourth session was devoted to machine learning and smart tools and modeling. Dr Meneghini used machine learning algorithms to identify optimal alignment outcomes that correlated with patient outcomes. Several parameters such as native tibial slope, femoral sagittal position and coronal limb alignment correlated with outcomes. Along the same lines, Bozic and coauthors demonstrated that using AI algorithms incorporated with PROM's improved levels of shared decision making and patient satisfaction. Dr Lombardi demonstrated that a mobile patient engagement platform that provided smart phone-based exercise and education was comparable to traditional methods. Dr Mahfouz demonstrated the accuracy of using ultrasound to produce 3D models of the bone compared to conventional CT based strategies and Dr Mahoney showed the valued of a preop 3D model in reproducing more normal knee kinematics. The last two talks of the session focused on some of the positives of the COVID-19 pandemic, namely the embracing of telemedicine by patients and surgeons as demonstrated by Dr Slover and the increasing and far reaching educational opportunities made available to residents and fellows during the pandemic. Session five focused on risk stratification and optimization prior to TKA. Dr O'Connor demonstrated that that the implementation of an optimization program preoperatively reduced length of stay and ED visits, and Charles Nelson's study showed that risk stratification tool can lower complication rates in obese patients undergoing TKA comparable to those that are nonobese. Dr Markel's study demonstrated that those who have preoperative depression and anxiety are at higher risk of complications and readmissions after surgery and these issues should be addressed preoperatively. Interestingly, a study by Dr Callaghan demonstrated that care improvement pathways have not lowered the gap in complications for morbidly obese patients undergoing TKA, Dr Barsoum argued that the overall complication rates were low and this patient cohort had significant gains in PROMS after TKA that would not be experienced if arbitrary cutoff for limited surgery were established. The final session on Friday, Session six, had several well done and interesting studies. There continues to be mounting evidence that liposomal bupivacaine has little effect on managing post-operative pain to warrant its increased use. Bill Macaulay and colleagues showed no change in pain scores, opioid consumption and functional scores when liposomal bupivacaine was discontinued at a large academic medical center. Dr Bugbee importantly demonstrated that a supervised ambulation program reduced falls in the early postoperative period. Several paper on healthcare economics were presented. Rich Iorio showed that stratifying complexity of total joint cases between hospitals with a system can be efficient and cost savings while Dr Jiranek demonstrated in his study that complex TKAs can be identified preoperatively and are associated with prolonged operative time and cost of care and consideration should be given in future reimbursement models to a complexity modifier. Dr Springer, in their evaluation of Medicare bundled payment models, demonstrated that providers and hospitals in historical bundled models that became efficient were penalized in the new model, forcing many groups to drop out and return to a fee for service model. Ron Delanois important work showed that social determinants can have a major negative impact on outcomes following TKA. Our final day on Saturday opened with Session seven, and several interesting paper on metal ions/debris in TKA. Dr Whitesides simulator study showed the absence of scratches and material loss in a ceramic TKA compared with Co-Cr TKA and suggested an advantage to this material in patients with metal sensitivity. Conversely, in a histological study of failed TKA, perivascular lymphocytic infiltration was not associated with worse clinical outcomes or differences in revision in a series of 617 aseptic revisions, 19% of which had PVLI found on histology. The Mayo group and Dr Trousdale however, noted that serum metal ion levels can be helpful in identifying implant failure in a group of revision TKAs, especially those with metallic junctions. Dr Dalury demonstrated nicely that use of maximally conforming inserts did not have a negative effect on implant loosening in a series of 76 revision TKA's at an average follow up of 7 years, while Kevin Garvin and his group showed no difference in end of stem pain between cemented and cementless stems in revision TKA. The final two studies in the session by Bolognesi and Peters respectively showed that metaphyseal cones continue to demonstrate excelled survivorship in rTKA setting despite extensive bone loss. Session eight was highlighted by a large series of revision reported by new member Dr Schwarzkopf, who showed that revision TKA done by high volume surgeons demonstrated better outcomes and lower revision rates compared to surgeon who did less than 18 rTKA's per year. Dr Maniar importantly showed that preoperatively, patients with high activity level and low pain and indicated by a high preop forgotten joint score did poorly following TKA while David Ayers nicely demonstrated that KOOS scores that assess specific postoperative outcomes can predict patient dissatisfaction after TKA. The final paper in this session by Max Courtney showed that the majority of surgical cancellations are due to medical issues, yet a minority of these undergo any intervention specifically for that condition, but they resulted in a delay of 5 months. The first two studies of Session nine focused on polyethylene thickness. Dr Backstein demonstrated no difference in KSS scores, change in ROM and aseptic revision rates based on polyethylene thickness in a series of 195 TKA's. An interesting lab study by Dr Tim Wright showed a surprising consistency in liner thickness choice among varying levels of surgeon experience that did not correlate with applied forces or gap stability estimates. Two studies looked specifically at the issue of tibial loosening and implant design. Nam and colleagues were not able to demonstrate concerning findings for increasing tibial loosening in a tibial baseplate with a shortened tibial keel at short term follow up, while Lachiewicz demonstrated a 19% revision or revision pending rate in 223 cemented fixed bearing ATTUNE TKA at a mean of 30 months. Our final session of the meeting, began with encouraging news, that despite only currently capturing about 40% of TJA's done in the US, the American Joint Replacement Registry data is representative of data in other representative US databases. An interesting study presented by Robert Barrack looked at bone remodeling in the proximal tibia after cemented and cementless TKA of two different designs. No significant difference was noted among the groups with the exception of the cemented thicker cobalt chrome tray which demonstrated significantly more bone mineral density loss. Along the same lines, a study out of Dr Bostrom's lab demonstrated treatment of a murine tibial model with iPTH prevents fibrous tissue formation and enhances bone formation in cementless implants. New Member Jamie Howard showed no difference in implant migration and kinematics of a single radius cementless design using either a measured resection or gap balancing technique and Dr Cushner show no difference in blood loss with cemented or cementless TKA with the use of TKA. The final two studies looked at staging and bilateral TKA's. Peter Sharkey showed that simultaneous TKA's were associated with higher complication compared to staged TKA and that staged TKA with less than a 90-day interval was not associated with higher risk. However, Mark Figgie showed that patients undergoing simultaneous TKA compared to staged TKA, missed 17 fewer days of work. In spite of the virtual nature of the meeting, there were some outstanding scientific interactions and the material presented will continue to generate debate and to guide the direction of knee arthroplasty as we move forwards

Purpose: First described in 1699, hydatid cyst in a muscle is extremely rare today, even in endemic areas. Material and methods: We report a retrospective series of nine cases of primary hydatid cyst observed between 1985 and 1998. The patients were predominantly women living in a rural area (mean age 37 years), who consulted for an isolated tumefaction of the thigh (left side in 7/9 cases) which had evolved for twelve months on the average without affecting the general health status. Ultrasonography was highly contributive, suggesting the diagnosis in all cases. Hydatic serology was positive in five cases. Computed tomography (n=3) and magnetic resonance imaging (n=2) provided supplementary information. Hydatid cysts were identified in the adductors (n=4), the quadriceops (n==3) and the three compartments (n=1). Results: Surgical treatment was performed in eight patients; en bloc resection of the hydatid cyst with peripheral muscle tissue in six cases and subtotal pericystectomy in two. Clinical and anatomic results are presented at mean six years follow-up. Discussion: We discuss the role of each radiographic examination for the diagnosis and search for extension of hydatid cysts as well as the therapeutic options depending on the clinical course and soft tissue involvement

Athletes are prone to iterated traumatic straining of sacroiliac joints and insertion of muscles in pelvic bones. The aim of our study was to show the connection between iterated trauma and staphylococcal infection in athletes. A compilation of data concerning 22 patients, all high-ranking athletes in Sweden, with pelvic skeletal infection (symphysitis, sacroiliitis and acetabular necrosis) is presented. Most of them were ball-players, 2 females and 20 males with an average age of 21 years. The onset was acute or subacute and the disease was commonly misinterpreted, mainly as an acute abdominal disease. Four patients erroneously underwent laparotomy for suspected appendicitis. Eight patients had skin lesions (5 purulent and 3 uninfected) at the onset and thus had a portal for possible entry for a bacterial impact in the pelvic skeleton. The only verified bacterial aetiology was Staphylococcus aureus in 19 cases (culture of blood and/or aspirated samples in 18 and serology only in 1). An early scintigraphy was of greater value than X-ray for diagnosis and was positive in 8/10 evaluable cases. In all, 12/18 had early positive plain radiological findings. Another patient (#22) had, except skeletal infection, a psoas abscess, diagnosed by Magnetic Resonance Imaging (MRI). Antistaphylococcal drugs administered parenterally for 1–2 weeks followed by oral drugs for a few months comprised a successful treatment and no patient had serious sequelae or relapse. The occurrence of abdominal and/or lower back pains concomitant to fever in young persons engaged in elite team sports should lead to a suspicion of pelvic pyogenic infection. Early scintigraphy and cultures of blood and aspirated material from the infection site was essential for the diagnosis. MRI has also been shown to be valuable

Aims

Tuberculosis (TB) is one of the biggest communicable causes of mortality worldwide. While incidence in the UK has continued to fall since 2011, Bradford retains one of the highest TB rates in the UK. This study aims to examine the local disease burden of musculoskeletal (MSK) TB, by analyzing common presenting factors within the famously diverse population of Bradford.

Purpose: To present our clinical and quality of life outcomes after one year treatment with our protocol including graft retention. Method: Seventeen of 1, 847 patients who underwent ACL reconstruction surgery were identified as infected following retrospective chart review in our institution (University of Ottawa) from 1995 to 2005. Mean age was 37 years old (range 18–56). Gender ratio was 14 male/ three female. Laterality 13 left/ four right knees. The diagnosis was achieved by clinical suspicion and serum markers (ESR, CPR, WBC) followed with aspiration and culture of intraarticular liquid. After that, our treatment protocol included IV antibiotics (empiric and culture guided) and knee arthroscopy performing debridement and lavage with 12L of saline irrigation as well as graft retention when possible. Clinical and Radiographic data were collected at a minimum of one year follow-up (IKDC, KT-1000, Lysholm, SF-12, Tegner, Cybex Strength testing). Results: The Incidence of septic arthritis following ACL reconstruction was 0, 92%. Bacteriology results were as follows: seven staphylococcus aureus, four Propionibac-terium acnes, one Klebsiella oxytoca, five no growth. The time from ACL reconstruction to first symptoms of infection was 37 days (range 4–63). The time from symptoms to arthroscopic debridement was 5, 5 days (range 0–33). Serology markers were as follows: ESR mean 69 (range 23–128), CPR 136 (50–387), WBC 10.3 (6–15). The average follow up was 41 months (range 12–85). Sixteen of 17 grafts were retained after 1.53 procedures per patient. Antibiotic treatment lasted 5.2 weeks on average. The average clinical outcomes were: Lysholm 77 (44–98), IKDC 74 (46–95), Quadriceps strength 71 % of non operative side, and Hamstrings strength 70 % of non operative side, KT -1000 side to side difference 1 mm (−3 to 4). Degenerative radiological changes were noted in three patients. Two later repeat reconstructions occurred due to instability (11,1%). No delayed recurrence of infection was noted. Conclusion: ACL reconstruction is a safe procedure being the incidence of septic arthritis in our series of 0, 92%. Our protocol of treatment is clinically effective and allows for a stable knee in 88, 9% of the patients avoiding the appearance of a delayed infection