In recent years, many studies demonstrated the efficacy of an early switch to oral antibiotics after surgical treatment in orthopaedic related infections. However, large analyses on periprosthetic joint infections (PJIs) are lacking. We conducted a retrospective observational multicenter study in patients diagnosed with an early postoperative PJI (i.e less than 3 months after the index arthroplasty) treated with debridement, antibiotics and implant retention (DAIR). Patients from Europe and the USA were included. These two cohorts served as a quasi-randomised trial since an early oral antibiotic switch is routine practice in Europe versus a long duration of intravenous (IV) antibiotic treatment in the USA. Failure was defined as the clinical need for: i) a second DAIR, ii) implant removal, iii) suppressive antibiotic treatment or iv) infection related death.Introduction
Material and Methods
This study aimed to externally validate promising preoperative PJI prediction models in a recent, multinational European cohort. Three preoperative PJI prediction models (by Tan et al., Del Toro et al., and Bülow et al.) which previously demonstrated high levels of accuracy were selected for validation. A multicenter retrospective observational analysis was performed of patients undergoing total hip arthroplasty (THA) and total knee arthroplasty (TKA) between January 2020 and December 2021 and treated at centers in the Netherlands, Portugal, and Spain. Patient characteristics were compared between our cohort and those used to develop the prediction models. Model performance was assessed through discrimination and calibration.Aim
Method
Debridement, antibiotics, and implant retention (DAIR) is a viable treatment option for acute periprosthetic joint infections (PJI). The landmark DATIPO trial of Bernard et al. concluded that six weeks is not non-inferior to 12-week antibiotic therapy for DAIR. However, it is unknown if suppressive antibiotic treatment (SAT) would improve patient outcomes. Therefore, our study aims to evaluate the utility of SAT after 12 weeks of therapy. We performed a retrospective study of patients with acute hip or knee PJI managed with DAIR at five institutions; in the U.S. (n=1), Netherlands (n=3), and Spain (n=1) from 2005–2020. We analyzed the effect of SAT using a Cox model among patients after 12 weeks of antibiotic treatment. The primary covariate of interest was whether the patient was on antibiotics after week 12, which was coded as a time-varying covariate. We decided a-priori to control for the clinically important risk factors such as age, sex, type of infection, modular exchange, joint, and presence of bacteremia and Aim
Method
The duration and extent of postoperative wound leakage after joint arthroplasty in patients with or without a complicated course, like a prosthetic joint infection (PJI), is currently unknown. Adequate differentiation between normal postoperative wound leakage and wound leakage due to a postoperative PJI is important and prevents unnecessary surgical procedures. We investigated the association between postoperative wound leakage and development of PJI in patients who used a previously developed mobile wound care app. A multicenter, prospective cohort study with patients aged 18 years or older after primary implantation or revision of a total joint arthroplasty. During 30 post-operative days after arthroplasty, patients recorded their wound status in the woundcare app. An algorithm calculated a daily score from imputed data. If the daily score exceeded a predefined threshold, the patients received an alert that advised them to contact their physician.Background
Methods
Low-grade infections are difficult to diagnose. As the presence of a chronic infection requires extensive surgical debridement and antibiotic treatment, it is important to diagnose a SII prior to surgery, especially when the hardware is revised. We investigated whether serum inflammatory markers or nuclear imaging can accurately diagnose a chronic spinal instrumentation infection (SII) prior to surgery. All patients who underwent revision spinal surgery after a scoliosis correction between 2017 and 2019 were retrospectively evaluated. The diagnostic accuracy of serum C-reactive protein (CRP) and Erythrocyte Sedimentation Rate (ESR), 18F-fluorodeoxyglucose positron emission tomography combined with computed tomography (FDG-PET/CT) and Technetium-99m-methylene diphosphonate (99mTc-MDP) 3-phase bone scintigraphy (TPBS) to diagnose infection were studied. Patients with an acute infection or inadequate culture sampling were excluded. SII was diagnosed if ≥ 2 of the same microorganism(s) were isolated from intra-operative tissue cultures.Aim
Method
Rifampin is considered as the antibiotic corner stone in the treatment of acute staphylococcal periprosthetic joint infections (PJI). However, if, when, and how to use rifampin has been questioned. We evaluated the outcome of patients treated with and without rifampin, and analysed the influence of timing, dose and co-antibiotic. Acute staphylococcal PJIs treated with surgical debridement between 1999 and 2017, and a minimal follow-up of 1 year were evaluated. Treatment failure was defined as the need for any further surgical procedure related to infection, PJI-related death, or the need for suppressive antimicrobial treatment.Aim
Method
Treatment success of debridement, antibiotics and implant retention (DAIR) is in early periprosthetic joint infection (PJI) is largely dependent on the presence or absence of a mature biofilm. In what time interval a mature biofilm develops is still unclear, and therefore, the time point at which DAIR should be disrecommended remains to be established. This large multicenter trial evaluated the failure rates of DAIR for different time intervals from index arthroplasty to DAIR in early PJI. We retrospectively evaluated patients with early PJI treated with DAIR between 1996 and 2016. Early PJI was defined as a PJI that developed within 90 days after index arthroplasty. Patients with hematogenous infections, arthroscopic debridements and a follow-up less than one year were excluded. Treatment failure was defined as 1) any further surgical procedure related to infection 2) PJI-related death, or 3) long-term suppressive antibiotics, all within one year after DAIR.Aim
Method
Obese patients are not only more likely to receive total joint arthroplasty, but are also more prone to postoperative complications. The most severe complication is a prosthetic joint infection (PJI), occurring two to four times more often in severely obese patients (BMI ≥ 35kg/m2) compared to non-obese patients. This higher risk for PJI may be attributed to higher glucose levels in case of diabetes mellitus, diminished wound healing or inadequate antibiotic prophylaxis. To ultimately improve the prevention measures for this specific patient category, we aimed to describe the clinical and microbiological characteristics of early acute PJI in severely obese patients. We retrospectively evaluated patients with early acute PJI of the hip and knee treated with DAIR between 2006 and 2016 in three Dutch hospitals. According to protocol, cefazolin was administered as antibiotic prophylaxis during arthroplasty and adjusted to bodyweight. PJI was diagnosed using the criteria described by the Musculoskeletal Infection Society. Early acute PJI was defined as less than 21 days of symptoms and a DAIR performed within 90 days after index surgery. Several clinical and microbiological variables were collected and analyzed. Severe obesity was defined as a BMI ≥ 35kg/m2.Aim
Method
White blood cell (WBC) scintigraphy for diagnosing fracture-related infections (FRIs) has only been investigated in small patient series. Aims of this study were (1) to establish the accuracy of WBC scintigraphy for diagnosing FRIs, and (2) to investigate whether the duration of the time interval between surgery and WBC scintigraphy influences its accuracy. 192 consecutive WBC scintigraphies with 99mTc-HMPAO-labelled autologous leucocytes performed for suspected peripheral FRI were included. The goldstandard was based on the outcome of microbiological investigation in case of surgery, or - when these were not available - on clinical follow-up of at least six months. The discriminative ability of the imaging modalities was quantified by several measures of diagnostic accuracy. A multivariable logistic regression analysis was performed to identify predictive variables of a false-positive or false-negative WBC scintigraphy test result.Aim
Method
Diagnosing or excluding a chronic prosthetic joint infection (PJI) prior to revision surgery can be a clinical challenge. To enhance accuracy of diagnosis, several biomarkers were introduced in recent years, but most are either expensive or not available as a rapid test. We compared the diagnostic accuracy of leucocyte esterase (€0.20 per sample), calprotectin (€20 per sample) and alpha defensin (€200 per sample). We prospectively evaluated PJI patients with chronic pain with or without prosthetic loosening between 2017 and 2018. Synovial fluid was collected prior to revision surgery. Leucocyte esterase was measured using a reagent strip (2+ considered as positive), and calprotectin and alpha defensin were measured using a lateral flow immunoassay. Intraoperative cultures (5 periprosthetic tissue samples, synovial fluid and sonication fluid) incubated for 9 days, were used as gold standard. At least two positive cultures of low-grade microorganisms with the same antibiogram were required to diagnose PJI.Aim
Method
Computer Assisted Surgery (CAS) and Patient Specific Instrumentation (PSI) have been reported to increase accuracy and predictability of tumour resections. The technically demanding joint-preserving surgery that retains the native joint with the better function may benefit from the new techniques. This cadaver study is to investigate the surgical accuracy of CAS and PSI in joint-preserving surgery of knee joint. CT scans of four cadavers were performed and imported into an engineering software (MIMICS, Materialise) for the 3D surgical planning of simulated, multiplanar joint-preserving resections for distal femur or proximal tibia metaphyseal bone sarcoma. The planned resections were transferred to the navigation system (OrthoMap 3D, Stryker) for navigation planning and used for the design and fabrication of the PSI. Each of the four techniques (freehand, CAS, PSI and CAS + PSI) was used in four joint-preserving resections. Location accuracy (the maximum deviation of distance between the planned and the achieved resections) and bone resection time were measured. The results were compared by using t-test (statistically significant if P< 0.05). Both the CAS+PSI and PSI techniques could reproduce the planned resections with a mean location accuracy of < 2 mm, compared to 3.6 mm for CAS assistance and 9.2 mm for the freehand technique. There was no statistical difference in location accuracy between the CAS+PSI and the PSI techniques (p=0.92) but a significant difference between the CAS technique and the CAS+PSI (p=0.042) or PSI technique (p=0.034) and the freehand technique with the other assisted techniques. The PSI technique took the lowest mean time of 4.78 ±0.97min for bone resections. This was significantly different from the CAS+PSI technique (mean 12.78 min; p < 0.001) and the CAS technique (mean 16.97 min; p = < 0.001). CAS and PSI assisted techniques help reproduce the planned multiplanar resections. The PSI technique could achieve the most accurate bone resections (within 2mm error) with the least time for bone resections. Combining CAS with PSI might not improve surgical accuracy and might increase bone resection time. However, PSI placement on the bone surface depends only on the subjective feeling of surgeons and may not apply if the extraosseous tumor component is large. Combining CAS with PSI could address the limitations.
In the last couple of years, several synovial biomarkers have been introduced in the diagnostic algorithm for a prosthetic joint infection (PJI). Alpha defensin-1 proved to be one of the most promising, with a high sensitivity and specificity. However, a major disadvantage of this biomarker is the high costs. Calprotectin is a protein that is present in the cytoplasm of neutrophils, and is released upon neutrophil activation. Its value has been established for decades as a (fecal) marker for inflammatory bowel disease. To determine the efficacy of synovial calprotectin in the diagnosis of a prosthetic joint infection.Introduction
Aim
Most types of bone tumor surgery require intra-operative imaging or measurement to control margins and prevent unnecessary bone loss. Computer Assisted Surgery (CAS) has been used as a replacement of fluoroscopy or direct measurement tools in four specific types of oncological orthopaedic surgical approaches. There are intralesional treatments, image-based resections, image-based resections with image-based reconstructions and image-based resections with imageless tumor prostheses reconstruction. Since 2006 we have performed 130 oncological surgeries with CAS. Most cases were excochleations, 64, where CAS replaces fluoroscopy as an intra-operative imaging modality. Advantages over fluoroscopy are real time three dimensional feedback, high-res image and no use of ionizing radiation. It is especially useful in larger lesions or lesions located in the femoral head or pelvis. Currently a study is being performed on patient satisfaction, recurrence and complications. Another application where CAS has often been used is in resections and segmental resections (together 45). These can be preplanned before surgery, incorporating the margin required, and checked intra-operatively. Coloration of the tumor, critical structures is useful to avoid these. Sometimes it's possible with careful planning to spare structures that otherwise probably would not confidently have spared. With hemicortical resection (5) it's possible to use CAS to exactly copy the shape of the resected bone to an allograft. A Ct scan of one case shows an average gap between host and graft of 0.9 mm (range 0–5.4) along the 6 cm resection. Finally in 16 cases of imageless use in placement of tumor prostheses it feels greatly helpful in reconstructing the joint line, length and correct rotation. There were 8 failures in these 130 cases with the system or software. Setup time was measured in 47 cases and was on average 6:50 (range 2:26–14:27). Indication and performance of CAS in orthopedic oncology is an under researched aspect of CAS. In our opinion CAS shows great promise in the field of orthopedic oncology and is a valuable tool in the operating room.
Adamantinoma are rare, low grade malignant, bone tumors, making up only 0.1–0.48 percent of primary malignant bone tumors. They occur predominantly in the long bones, especially the tibia. Histogenetically it is thought that it originates from embryological displacement of basal epithelium of the skin, although other hypotheses have been proposed. Clinically most patients present with swelling and possible bending of the tibia, painful or painless. It's often noticed in an earlier stadium, but symptoms are non-specific and have a slow progressive character. Median patient age is 25 to 35 years, with a range from two to 86 years. It is slightly more common in men than woman, with a ratio of 5:4. Occurrence in children is even rarer. A study by Van Rijn et al. finds only 119 references, and presents six more cases. Treatment is the same. An MRI-scan should be performed to check for metastasis, loco regional staging and for operative planning. Operative excision and reconstruction is necessary to prevent metastasis and maintain load bearing capacity. Generally these resections and reconstructions are done without objective measurements. The surgeon uses a rule of thumb, like a sculptor, or ruler approach to recreate the excised bone, either with allo- or autograft materials. An optimal fit, i.e. a minimal space between tibia and graft, is not always achieved, possibly resulting in pathological fractures. This risk of pathological fractures lengthens recovery time. The fractures elongate hospitalization time and recovery time and are a heavy burden to patients. Computer assisted surgery (CAS) systems, used for example in prosthesis placement, offer objective measurements in 3d space of hard structures with high accuracy. These can be used to produce an accurate copy of the resected bone. If the reconstruction accurately fits the bone defect that's left after the resection, it's likely that the occurrence of pathological fractures decreases. An adamantinoma in the tibia of a 12 year old boy was treated. Surgery consisted of hemicortical resection and inlay allograft reconstruction. The software used was the Orthomap navigation software (Stryker). A donor bone was supplied with help from the bone bank. The technical approach to the reconstruction was the planning of resection planes around the tumor. As the CT scale for both the patient and allograft bone is the same, the resection planes in the patient navigation setup could be copied to the allograft creation setup. Normal CAS setup was performed after first incision, with a tracker attached to the tibia. It was planned that a navigated bone saw would be used for the cutting. The tracker was attached to the saw with a new attachment, and calibrated in the universal calibration tool. During the surgery the oscillating saw proved to be impossible to navigate. The instrument calibration module was not able to accurately registered the saw, this despite accurate registrations in pre-operative testing. The CAS system was used however for accurately determining the saw planes. The planes were traced with the pointer tool. Then a non-navigated saw was used to perform both trapezoid shaped resections. A similar CAS setup was performed on the donor bone. The reconstruction was a good fit. The skin was closed in layers. Post-operative x-ray control was performed. Operation time was just over two hours. Currently the follow-up time is five months. There have been no complications and the control x-rays show good allograft ingrowth. While the original operation plan couldn't be performed the principle of computer assisted reconstruction has its merits. This was a proof of concept. The navigation was accurate to less than 1 mm, and the trapezoid resection shape guarantees a good fit. However the method of resection of the drawn planes by non-navigated bone saw was not accurate enough, because of the saw oscillations. There was improvement in operation time. With more accurate means of resection, as for example a computer controlled laser or water-jet, this type of reconstruction could have other very interesting applications.
