Aim. Adverse tissue reactions have been a concern in relation to metal components, particularly in hip replacements. We look at a possible correlation between hip joint effusion and metal ion levels. Materials and methods. 56 patients,(42M, 14F) agreed to the study. All had metal-on-mental arthroplasties. Average age was 64.2 (SD 9.8). All patients were asymptomatic. Ultrasound examination performed by one ultrasonographer, using a Sonosite M-Turbo machine with a C60X/5-2 MHz transducer. Cobalt levels were assessed using an inductively coupled plasma mass spectrometer. Chromium levels were assessed using a graphite furnace atomic absorption spectrometer. Results. Average blood ion levels were:. Cobalt 39.02 nmol/L. (SD41.18) range 3 to 215. Chromium 52.51 nmol/L (SD47.48) range 5 to 284. Average Volume: 10.38ml (SD21.3) Range 0 to 219. Conclusion. There was no statistically significant correlation between joint effusion and metal ion levels

Background. Exebacase, an antistaphylococcal lysin in Phase 3 of development as a treatment for S. aureus bacteremia/right-sided endocarditis has demonstrated antibiofilm activity in vitro and has previously been used as salvage therapy in four patients with relapsing multidrug-resistant (MDR) S. epidermidis knee prosthetic joint infection (PJI) using a procedure called LysinDAIR (administration of the lysin during the performance of an arthroscopic DAIR). Materials/methods. We performed a single center, exploratory, open-label prospective study using the LysinDAIR procedure in patients with chronic (inoculation >3 months prior to treatment) coagulase-negative staphylococci (CNS) PJI of the knee with two different clinical presentations and treatment paradigms. Cohort A: first episode of CNS knee PJI, for whom the LysinDAIR was followed by clindamycin + levofloxacin planned to be prescribed for three months and then stopped; and Cohort B: relapsing episodes of MDR CNS knee PJI for whom the LysinDAIR was followed by primary antimicrobial therapy for three months, followed by suppressive antimicrobial therapy (SAT). Exebacae susceptibility testing was performed before treatment for each patient. In agreement with the French Health authority, exebacase (2 to 3.5 total mg in 30–50 ml (∼0.067 – 0.075 mg/m) was administered directly into the joint during arthroscopy. Results. Eight patients were treated. Exebacase administration was well tolerated by all patients and no serious adverse drug reactions to exebacase were reported. In cohort A (n=4), patients had susceptible S. epidermidis PJI, a painful joint effusion without fistula and without loosening, and received three months of levofloxacin + clindamycin (one patient received an alternative regimen following antibiotic adverse events) and then antibiotics were stopped. During a follow-up of 14, 19, 26 and 36 months, no relapse, no recurrence of the joint effusion and no loosening occurred. In cohort B (n=4), patients had MDR CNS, clinical signs of septic arthritis with a joint effusion without fistula and without loosening and received daptomycin + linezolid or doxycycline. One patient died from COVID-19 at week 4. SAT (tedizolide, n=2; doxycycline, n=1) was then prescribed to other patients. One experienced an infection relapse involving S. caprae under tedizolid therapy at six months. The two other patients continue to do well under SAT 8 and 12 months after the LysinDAIR procedure. Conclusions. The LysinDAIR procedure is a minimally invasive procedure, which has been shown to be easy-to-perform, safe, and has the potential for use as initial treatment or salvage therapy in patients with CNS chronic knee PJI

Background. Bacteriophages are natural viruses of interest in the field of PJI. A paper previously reported the PhagoDAIR procedure (use of phages during DAIR) in three patients with PJI for whom explantation was not desirable. As the need to isolate the pathogen before surgery to perform phage susceptibility testing is a strong hindrance for the development of this procedure, we developed post-operative phage injections using ultrasound, in patients infected with S. aureus and/or P. aeruginosa who were eligible for the PhagoDAIR procedure, but for whom phages were not available at the time of surgery. Materials/Methods. We performed a single center, exploratory, prospective cohort study including patients with knee PJI who received phage therapy with ultrasound after performance of a DAIR or a partial prosthesis exchange. All patients had PJI requiring conservative surgery and suppressive antimicrobial therapy (SAT) as salvage procedure. Each case was discussed in multidisciplinary meetings in agreement with French health authority, based on the clinical presentation, and the phage susceptibility testing. The cocktail of highly concentrate active phages (5 mL; about 10. e. 9 PFU/mL) was extemporaneous prepared and administered three times directly into the joint using sonography (1 injection per week during 3 weeks) during the postoperative period, before switching antibiotics to SAT. Results. Seven patients received phages under sonography after the DAIR, and one after a partial exchange (mean age 71 years). All had resection prosthesis or constrained knee prosthesis. Among these seven patients, three were infected with S. aureus (including one MRSA), two were infected with P. aeruginosa (one was a multidrug-resistant isolate), one was infected with both S. aureus and P. aeruginosa and the last one was infected with MRSA, S. epidermidis and Corynebacterium spp.. All patients received a cocktail of active phages provided by Pherecydes Pharma targeting S. aureus or P. aeruginosa. No adverse event was recorded during or after the local injections. All patients were switched to SAT after a primary postoperative antimicrobial therapy of three months. Under SAT, the patient with S. epidermidis co-infection developed a relapse due to the S. epidermidis. With a mean follow-up of 13 months after surgery (from 9 to 24 months), the outcome was favorable for all patients without any sign of infection; none of them had abnormal pain, joint effusion or loosening. Conclusions. Postoperative administration of phages using sonography is a potentially useful procedure in patients with complex PJI for whom a conservative approach is desirable

Background. Septic arthritis diagnostic is an emergency which implies a treatment with antibiotics and hospitalization. The diagnosis is based on the cytobacteriological examination of the synovial fluid (SF), but direct bacteriological examination is insensitive, and the result of the culture is obtained only after several days. Therefore, there is still a need for a rapid, simple and reliable method for the positive diagnosis of septic arthritis. Such method must allow avoiding both unrecognized septic arthritis leading to major functional consequences, and overdiagnosis that will induce unnecessary expensive hospitalization and unjustified treatment. Mid-infrared (MIR) spectroscopy, that gives a metabolic profiling of biological fluids, has been proposed for early and fast diagnosis. Objectives. To confirm the MIR spectroscopy to discriminate SF samples from patients with septic arthritis from other causes of joint effusion. Methods. Synovial fluids from 402 patients referred for suspected arthropathies were prospectively collected in six hospitals and stored at °80°C. The infrared absorption spectrum was acquired for each of the frozen samples using a chalcogenide fiber biosensor. The most informative spectral variables were selected and then used to develop an algorithm. Then, the algorithm has been validated on independent synovial fluids collected straight after arthrocentesis from 86 patients. Results. The calibration (n=402) and validation (n=86) cohorts consists of synovial fluid samples from patients exhibiting various etiologies. These samples (n=488), by using SF bacteriological analysis and culture and 16S PCR analysis were classified as septic arthritis (n=43) or non-septic arthritis (n=443). On the calibration cohort, the performances of the algorithm show a sensitivity of 90%, a specificity of 90%, a NPV of 99% and a PPV of 41%, the area under the ROC curve (AUROC) was 0.95. On the validation cohort, the performances of the algorithm show a sensitivity of 92%, a specificity of 81%, a NPV of 98% and a PPV of 46%, the area under the ROC curve (AUROC) was 0.90. Conclusions. This study confirms the diagnostic performances of MIR spectroscopy for the discrimination between septic and non-septic synovial fluids. The high negative predictive value and the very short time (within ten minutes) required to obtain the result makes it possible to quickly rule out an infection diagnosis

A total knee replacement (TKR) with instability is one in which the supporting soft tissues have failed or are unable to function due to component size and/or position. Instability following TKR can lead to the need for surgery in 10–22% of revision cases. Patients may complain of symptoms of giving way, difficulty climbing stairs, and the sensation that their knee may buckle under stress. Physical findings may include soft-tissue tenderness in the peripatellar and pes anserine regions, recurrent joint effusions, and joint laxity. The cause of instability after TKR should be determined pre-operatively so the problem may be corrected at the time of revision. Instability after TKR may be due to component loosening, ligament rupture/incompetence, component malposition, mismatched flexion/extension gaps, or failure to correct ligament imbalance at the time of the index procedure. A common scenario after a cruciate-retaining TKR is that of PCL rupture, thus leading to instability in flexion and excessive posterior translation of the tibia. Other scenarios leading to TKR instability are pre-operative valgus alignment with MCL stretching, resulting in the post-operative recurrence of medial instability; or excessive resection of the posterior femoral condyles from undersizing of the femoral component, leading to laxity in flexion. The treatment of instability after TKR generally requires component revision and balancing of the flexion and extension gaps. Isolated ligament reconstruction is not successful in the setting of a prosthetic joint due to the lack of inherent joint stability. At the time of revision, the surgeon must carefully assess the flexion gap; often posterior femoral augments must be used to upsize the femoral component and tighten the flexion space relative to the extension space; for this reason, isolated polyethylene exchange is not successful for flexion instability. For instability in the varus/valgus plane, rebalancing the knee by performing ligament releases and using a more stabilizing polyethylene insert may by sufficient. The results of revision TKR for instability has been successful in the majority of cases, decreasing the symptoms of giving way and difficulty stairclimbing. A careful assessment of the varus/valgus stability of the prosthetic knee and the flexion/extension spaces at the time of revision TKR, along with the use of augments and more stabilised articulations, is mandatory in order to achieve good results

A total knee replacement (TKR) with instability is one in which the supporting soft tissues have failed or are unable to function due to component size and/or position. Instability following TKR can lead to the need for surgery in 10–22% of revision cases. Patients may complain of symptoms of giving way, difficulty climbing stairs, and the sensation that their knee may buckle under stress. Physical findings may include soft-tissue tenderness in the peripatellar and pes anserine regions, recurrent joint effusions, and joint laxity. The cause of instability after TKR should be determined pre-operatively so the problem may be corrected at the time of revision. Instability after TKR may be due to component loosening, ligament rupture/incompetence, component malposition, mismatched flexion/extension gaps, or failure to correct ligament imbalance at the time of the index procedure. A common scenario after a cruciate-retaining TKR is that of PCL rupture, thus leading to instability in flexion and excessive posterior translation of the tibia. Other scenarios leading to TKR instability are pre-operative valgus alignment with MCL stretching, resulting in the post-operative recurrence of medial instability; or excessive resection of the posterior femoral condyles from undersizing of the femoral component, leading to laxity in flexion. The treatment of instability after TKR generally requires component revision and balancing of the flexion and extension gaps. Isolated ligament reconstruction is not successful in the setting of a prosthetic joint due to the lack of inherent joint stability. At the time of revision, the surgeon must carefully assess the flexion gap; often posterior femoral augments must be used to upsize the femoral component and tighten the flexion space relative to the extension space; for this reason, isolated polyethylene exchange is not successful for flexion instability. For instability in the varus/valgus plane, rebalancing the knee by performing ligament releases and using a more stabilizing polyethylene insert may by sufficient. The results of revision TKR for instability has been successful in the majority of cases, decreasing the symptoms of giving way and difficulty stairclimbing. A careful assessment of the varus/valgus stability of the prosthetic knee and the flexion/extension spaces at the time of revision TKR, along with the use of augments and more stabilised articulations, is mandatory in order to achieve good results

Background. Osteomyelitis can be difficult to diagnose. Unlike septic arthritis no defined diagnostic criteria exist as a guide. Inflammatory markers are frequently utilized at initial presentation, (in addition to white cell count). Methods. All radiologically confirmed cases of long bone osteomyelitis without septic arthritis, joint effusion or abscess, in paediatric patients, presenting to one hospital over an eighteen-month period were included. These patients were compared with all culture positive septic arthrides presenting to the same hospital within the same time period. Inflammatory markers taken on the day of admission were studied. Results. Thirty-seven patients with long bone osteomyelitis and thirteen with culture positive septic arthritis were identified. The two groups were comparable with regards to age and gender. At presentation 65% of the osteomyelitis patients had an ESR less than 40mm/hour, 48% below 20mm/hour and 19% within the normal range. 23% of the septic arthritis patients had an ESR below 40mm/hour, and none had an ESR below 20mm/hour or in the normal range. The CRP was in the normal range in 46% of the osteomyelitis patients and none of the septic arthritis patients. The average ESR and CRP in the osteomyelitis patients were 47mm/hour and 35mg/L respectively, while in the septic arthritis group these were 72mm/hour, (P< 0.021), and 107mg/L, (P< 0.028). Conclusions. The initial rise in inflammatory markers due to long bone osteomyelitis is significantly less than that in septic arthritis. A proportion of patients presenting with osteomyelitis have normal inflammatory markers at presentation. A high index of suspicion is required in diagnosing osteomyelitis, and inflammatory markers, while a useful adjunct to monitoring treatment, may offer false reassurance regarding the initial diagnosis

It is very difficult to perform total knee arthroplasty (TKA) for severe varus bowing deformity of femur. We performed simultaneous combined femoral supra-condyle valgus osteotomy and TKA for the case had bilateral varus knees with bowing deformity of femurs. Case presentation. A 62-year-old woman consulted our clinic with bilateral knee pain and walking distability. She was diagnosed rickets and had bilateral severe varus bowing deformity of femurs from an infant. Her height was 133 cm and body weight was 51 kg. Bilateral femur demonstrated severe bowing and her knee joint demonstrated varus deformity with medial joint line tenderness, no local heat, and no joint effusion. Bilateral knee ROM was 90 degrees with motion crepitus. Bilateral lower leg demonstrated mild internal rotation deformity. Bilateral JOA knee score was 40 Roentgenogram demonstrated knee osteoarthritis with incomplete development of femoral condyle. Mechanical FTA angles were 206 degree on the right and 201 on the left. She was received right simultaneous femoral supra-condyle valgus osteotomy with TKA was performed at age 63. Key points of surgical techniques were to use the intramedullary guide for valgus osteotomy as temporary reduction and fixation then performed mono-cortical locking plate fixation. Several mono cortical screws were exchanged to bi-cortical screws after implantation of the femoral component with long stem. Cast fixation performed during two weeks and full weight bearing permitted at 7 weeks after surgery. Her JOA score was slightly improved 50 due to other knee problems at 9 months after surgery, her right mechanical FTA was decreased to 173, and she received left simultaneous femoral supra-condyle valgus osteotomy with TKA as the same technique at April of this year. She has been receiving rehabilitation at now. Conclusions. Most causes of varus knee deformity are defect or deformity of medial tibial condyle and TKA for theses cases are not difficult to use tibial augment devices. However the cases like our presentation need supra-femoral condyle osteotomy before TKA. It was easy and useful to use intramedullary guide for valgus osteotomy as temporary reduction and fixation then performed mono-cortical locking plate fixation before TKA

In an effort to understand the role of metal ion analysis and how it relates to revision surgery and implant wear, four revised MOM cases were reviewed. The first case was revised for acute infection and is representative of the low bearing wear predicted by MOM simulator studies. Two of the four cases had apparent anterior subluxation as a result of hip hyperextension occurring with long stride gaits. The last case is a true hypersensitivity response to CoCr ions. All four MOM prostheses were implanted by one surgeon and revised by the same surgeon approximately 6–8 years postoperatively. The implants had been positioned satisfactorily with inclination angles 45°–55° and anteversion angles 28°–42°. Patient A (76 y/o female) with bilateral MOM hip replacements, was revised at approximately 8 years due to infection and had moderately elevated ions at the time of revision surgery (Co = 5, Cr = 2.3, Ti = 4). Only the femoral head was retrieved in this case. Retrieval analysis identified a well defined main-wear zone and one polar stripe. The CMM indicated there was minimal wear overall (form factor = 11 μm). Patient B (33 y/o male) with bilateral MOM hip replacements, was revised at approximately 8 years due to pain, popping/catching sensations, and elevated ions (Co = 33, Cr = 17, Ti = 90). Intraoperatively, the implant was observed subluxing superiorly from the acetabular cup with anterior rotation of the leg. Both the femoral head and acetabular cup were retrieved. Retrieval analysis identified a well defined main-wear zone and multi-directional polar stripe formations similar to those reported on dislocated implants (Figure 1)[McPherson 2012, 2013]. The CMM indicated that overall wear was significant (form factor > 100 μm). Patient C (77 y/o female) was revised at approximately 6 years due to pain, suspected implant loosening, osteolytic cysts determined by CT, and highly elevated ions (co = 164, Cr = 45, Ti = 33). Intraoperatively, there was evidence of wear including darkly stained tissue and osteolytic cysts. Both the femoral head and acetabular cup were retrieved. Retrieval analysis identified a well defined main-wear zone and one polar stripe. CMM indicated considerable wear (head form factor > 200, cup form factor >300). Patient D (45 y/o female) was revised at approximately 6 years due to pain, apparent reactive response joint effusion, and moderately elevated ions (Co = 5, Cr = 6, Ti = 71). Only the femoral head was retrieved. Retrieval analysis identified a well defined main-wear zone and one polar stripe. Minimal wear was indicated by CMM (form factor = 21). These four cases demonstrate distinct failure models of MOM hips and their respective metal ion results. Due to the diversity of patient location, a variety of clinical labs were utilized for this patient population. Caution should be used in interpreting metal ion analysis, as there are still no standards. Figure 1: Retrieval analysis of stripe wear identified on femoral head from patient B. Figure 2: Femoral head from patient C showing broader polar stripe associated with anterior subluxation in comparison to narrow polar stripe found on femoral head from patient A

Aims

The aim of this study was to analyze the prevalence of culture-negative periprosthetic joint infections (PJIs) when adequate methods of culture are used, and to evaluate the outcome in patients who were treated with antibiotics for a culture-negative PJI compared with those in whom antibiotics were withheld.

Aims

The aticularis genu (AG) is the least substantial and deepest muscle of the anterior compartment of the thigh and of uncertain significance. The aim of the study was to describe the anatomy of AG in cadaveric specimens, to characterize the relevance of AG in pathological distal femur specimens, and to correlate the anatomy and pathology with preoperative magnetic resonance imaging (MRI) of AG.