Aim. Infection is one of the worst complications following total joint arthroplasty, which is often associated with significant morbidity. Currently, due to the global burden of multidrug-resistant Gram-negative bacteria (MDR-GNB) infections, few multicentre studies have described a microbiological shift from Gram-positive cocci (GPC) towards MDR-GNB PJI (prosthetic joint infection). Additionally, the emergence of MDR-GNB impacts the therapeutic options and may increase the rate of PJI treatment failure. The purpose of the present study was to describe the predisposing factors associated to failure of treatment in an orthopaedic reference hospital in Brazil from 2014 through 2019. Method. Retrospective case-control analysis of patients treated for MDR-GNB PJI over a five-year period. Data were collected from medical, surgical and laboratory records. PJI were defined according the current MSIS criteria. MDR was defined as non-susceptibility to at least one agent in three or more antimicrobial categories. Patients with PJI with at least two positive tissue cultures for MDR-GNB were selected. The control group was patient with PJI caused by multisensitive organism (GNB or GPC). Absence of signs and symptoms of infection during the follow-up period was defined as cure. Definition of failure: death, need for another course of antibiotic, or the need for another surgical procedure to control the infectious site (relapse). Results. A total of 104 patients were selected, 59 patients in the MDR-GNB PJI group and 44 in the control group. Two outcomes were compared: cure or failure. The overall 1-year survival rate was 65.3% with the median survival time being 207.08 days. In the MDR-BGN infection group the 1-year survival rate was 59.3% and the average time of survival was 141.14 days. In contrast, in the Control group the 1-year survival rate was 73.8% with an average survival time of 230.29 days (p = 0.023). HR: 2.447, IC 1.099–5.448. The independent variables in the multivariate analysis associated to treatment failure were MDR-BGN infection (p = 0.023) HR 2,447 IC 1,099 –5,448, revision surgery (p = 0.042) HR 2,027 IC: 2,027–4,061, presence of comorbidities (p = 0.048) HR 2,508 IC: 0,972- 6,469 and previous antimicrobial use in the last 3 months (p = 0.022). HR 2,132 IC: 1,096- 4,149. Conclusions. GNB-MDR PJI increases approximately 2.5 times the chance of unfavourable outcome such as death and infectious relapse compared to infections with other multisensitive microorganism

Several attempts have been made to treat medial compartment OA of the knee with mobile spacers. All have met with dismal failure. This presentation explores the history of attempts to treat OA in the younger knee with mobile spacers and explains why they were all doomed to fail. Sources of information for this presentation include the published peer reviewed literature, publically available documents, and an insiders view of some of the failed attempts to solve the problem of medial compartment OA with mobile spacers. All attempts to treat medial compartment OA of the knee with mobile spacers have failed. The unispacer has been a failure with a 60% revision rate at three years. The ABS intercushion had a 100% revision rate at one year and in many cases caused permanent damage to the host knees. The Salucartilage spacer was implanted in one patient only and failed within 48 hours. Mobile spacers do not work, are never likely to work, and are not indicated for the treatment of medial compartment osteoarthritis of the knee

Background. Total knee prostheses are continually being redesigned to improve performance, longevity and closer mimic kinematics of the native knee. Despite continued improvements, all knee implants even those with proven design features, have failures. We identified a cohort of patients with isolated tibial component failures that occurred in a popular and successful knee system. Our purpose was to (1) characterize the observed radiographic failure pattern; (2) investigate the biologic response that may contribute to the failure; and (3) to determine if the failure mechanism was of a biological or a mechanical nature. Methods. Twenty-one knees from 19 patients met the inclusion criteria of having isolated tibial component failure in a commonly used knee implant system. Radiographs from the primary and revision knee surgery were analyzed for implant positioning and failure pattern, respectively. Inflammatory biomarkers IL-1β, IL-6 and TNF-α were available in 16/21 knees and peripheral CD14. +. /16. +. monocytes were measured in 10 of the above mentioned 16 knee revisions. Additionally, white blood cell (WBC) count, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) were measured to rule out infection as the cause of the cytokine upregulation. Results. Radiograph findings demonstrated that all of the 21 tibial components were implanted in either neutral or 2–3° varus position, none of the revisions were implanted in valgus (figure 1). All tibias showed obvious radiographic loosening and failed into varus. The inflammatory biomarkers IL-1b, IL-6, & TNF-a were negative. WBC, ESR, CRP were normal. Peripheral CD14+/16+ and total CD16+ monocytesmeasurements were consistent with previous findings of patients with osteoarthritis (figure 2). Conclusions. The findings supported a mechanical failure mechanism rather than that of a wear debris induced inflammatory pattern. The loosening, collapse and debonding from the cement may have been related to the implantation technique, stresses due to rotational freedom of the implant, or patient characteristics/behavior. For any figures or tables, please contact authors directly (see Info & Metrics tab above).

Meniscal repairs are commonly performed during anterior cruciate ligament (ACL) reconstruction. This study aimed to identify the risk factors for meniscal repair failure following concurrent primary ACL reconstruction. Primary ACL reconstructions with a concurrent repair of a meniscal tear recorded in the New Zealand ACL Registry between April 2014 and December 2018 were analyzed. Meniscal repair failure was defined as a patient who underwent subsequent meniscectomy, and was identified after cross-referencing data from the ACL Registry with the national database of the Accident Compensation Corporation (ACC). Multivariate Cox regression was performed to produce hazard ratios (HR) with 95% confidence intervals (CI) to identify the patient and surgical risk factors for meniscal repair failure. 2041 meniscal repairs were analyzed (medial = 1235 and lateral = 806). The overall failure rate was 9.4% (n = 192). Failure occurred in 11.1% of medial (137/1235) and 6.8% of lateral (55/806) meniscal repairs. The risk of medial failure was higher with hamstring tendon autografts (adjusted HR = 2.00, 95% CI 1.23 – 3.26, p = 0.006) and in patients with cartilage injury in the medial compartment (adjusted HR = 1.56, 95% CI 1.09 – 2.23, p = 0.015). The risk of lateral failure was higher when the procedure was performed by a surgeon with an annual case volume of less than 30 ACL reconstructions (adjusted HR = 1.92, 95% CI 1.10 – 3.33, p = 0.021). Age, gender, time from injury-to-surgery and femoral tunnel drilling technique did not influence the risk of meniscal repair failure. When repairing a meniscal tear during ACL reconstruction, the use of a hamstring tendon autograft or the presence of cartilage injury in the medial compartment increases the risk of medial meniscal repair failure. Lower surgeon case volume increases the risk of lateral meniscal repair failure

The Accolade®TMZF is a taper-wedge cementless metaphyseal coated femoral stem widely utilized from 2002-2012. In recent years, there have been reports of early catastrophic failure of this implant. Establishing a deeper understanding of the rate and causes of revision in patients who developed aseptic failure in stems with documented concerns about high failure rates is critical. Understanding any potential patient or implant factors which are risk factors for failure is important to inform both clinicians and patients. We propose a study to establish the long-term survival of this stem and analyze patients who underwent aseptic revision to understand the causes and risk factors for failure. A retrospective review was undertaken of all patients who received a primary total hip arthroplasty with an Accolade® TMZF stem at a high-volume arthroplasty center. The causes and timing of revision surgery were documented and cross referenced with the Canadian Institute of Health Information Discharge Abstract Database to minimize loss to follow-up. Survivorship analysis was performed with use of the Kaplan-Meier curves to determine the overall and aseptic survival rates at final follow-up. Patient and implant factors commonly associated with aseptic failure were extracted and Cox proportional hazards model was used. A consecutive series of 2609 unilateral primary THA patients implanted with an Accolade®TMZF femoral hip stem were included. Mean time from primary surgery was 12.4 years (range 22 days to 19.5 years). Cumulative survival was 96.1% ± 0.2 at final follow-up. One hundred and seven patients underwent revision surgery with aseptic loosening of the femoral component was the most common cause of aseptic failure in this cohort (33/2609, 1.3%). Younger age and larger femoral head offset were independent risk factors for aseptic failure. To our knowledge, this is the largest series representing the longest follow-up of this taper-wedge cementless femoral implant. Despite early concerns, the Accolade® TMZF stem has excellent survivorship in this cohort. Trunnionosis as a recognized cause for revision surgery was rare. Younger age and larger femoral head offset were independent risk factors for aseptic failure

Bone turnover and the accumulation of microdamage are impacted by the presence of skeletal metastases which can contribute to increased fracture risk. Treatments for metastatic disease may further impact bone quality. The present study aims to establish a preliminary understanding of microdamage accumulation and load to failure in osteolytic vertebrae following stereotactic body radiotherapy (SBRT), zoledronic acid (ZA), or docetaxel (DTX) treatment. Twenty-two six-week old athymic female rats (Hsd:RH-Foxn1rnu, Envigo, USA) were inoculated with HeLa cervical cancer cells through intracardiac injection (day 0). Institutional approval was obtained for this work and the ARRIVE guidelines were followed. Animals were randomly assigned to four groups: untreated (n=6), spine stereotactic body radiotherapy (SBRT) administered on day 14 (n=6), zoledronic acid (ZA) administered on day 7 (n=5), and docetaxel (DTX) administered on day 14 (n=5). Animals were euthanized on day 21. T13-L3 vertebral segments were collected immediately after sacrifice and stored in −20°C wrapped in saline soaked gauze until testing. µCT scans (µCT100, Scanco, Switzerland) of the T13-L3 segment confirmed tumour burden in all T13 and L2 vertebrae prior to testing. T13 was stained with BaSO. 4. to label microdamage. High resolution µCT scans were obtained (90kVp, 44uA, 4W, 4.9µm voxel size) to visualize stain location and volume. Segmentations of bone and BaSO. 4. were created using intensity thresholding at 3000HU (~736mgHA/cm. 3. ) and 10000HU (~2420mgHA/cm. 3. ), respectively. Non-specific BaSO. 4. was removed from the outer edge of the cortical shell by shrinking the segmentation by 105mm in 3D. Stain volume fraction was calculated as the ratio of BaSO. 4. volume to the sum of BaSO. 4. and bone volume. The L1-L3 motion segments were loaded under axial compression to failure using a µCT compatible loading device (Scanco) and force-displacement data was recorded. µCT scans were acquired unloaded, at 1500µm displacement and post-failure. Stereological analysis was performed on the L2 vertebrae in the unloaded µCT scans. Differences in mean stain volume fraction, mean load to failure, and mean bone volume/total volume (BV/TV) were compared between treatment groups using one-way ANOVAs. Pearson's correlation between stain volume fraction and load to failure by treatment was calculated using an adjusted load to failure divided by BV/TV. Stained damage fraction was significantly different between treatment groups (p=0.0029). Tukey post-hoc analysis showed untreated samples to have higher stain volume fraction (16.25±2.54%) than all treatment groups (p<0.05). The ZA group had the highest mean load to failure (195.60±84.49N), followed by untreated (142.33±53.08N), DTX (126.60±48.75N), and SBRT (95.50±44.96N), but differences did not reach significance (p=0.075). BV/TV was significantly higher in the ZA group (49.28±3.56%) compared to all others. The SBRT group had significantly lower BV/TV than the untreated group (p=0.018). Load divided by BV/TV was not significantly different between groups (p=0.24), but relative load to failure results were consistent (ZA>Untreated>DTX>SBRT). No correlations were found between stain volume fraction and load to failure. Focal and systemic cancer treatments effect microdamage accumulation and load to failure in osteolytic vertebrae. Current testing of healthy controls will help to further separate the effects of the tumour and cancer treatments on bone quality

Bone turnover and the accumulation of microdamage are impacted by the presence of skeletal metastases which can contribute to increased fracture risk. Treatments for metastatic disease may further impact bone quality. The present study aims to establish a preliminary understanding of microdamage accumulation and load to failure in osteolytic vertebrae following stereotactic body radiotherapy (SBRT), zoledronic acid (ZA), or docetaxel (DTX) treatment. Twenty-two six-week old athymic female rats (Hsd:RH-Foxn1rnu, Envigo, USA) were inoculated with HeLa cervical cancer cells through intracardiac injection (day 0). Institutional approval was obtained for this work and the ARRIVE guidelines were followed. Animals were randomly assigned to four groups: untreated (n=6), spine stereotactic body radiotherapy (SBRT) administered on day 14 (n=6), zoledronic acid (ZA) administered on day 7 (n=5), and docetaxel (DTX) administered on day 14 (n=5). Animals were euthanized on day 21. T13-L3 vertebral segments were collected immediately after sacrifice and stored in −20°C wrapped in saline soaked gauze until testing. µCT scans (µCT100, Scanco, Switzerland) of the T13-L3 segment confirmed tumour burden in all T13 and L2 vertebrae prior to testing. T13 was stained with BaSO. 4. to label microdamage. High resolution µCT scans were obtained (90kVp, 44uA, 4W, 4.9µm voxel size) to visualize stain location and volume. Segmentations of bone and BaSO. 4. were created using intensity thresholding at 3000HU (~736mgHA/cm. 3. ) and 10000HU (~2420mgHA/cm. 3. ), respectively. Non-specific BaSO. 4. was removed from the outer edge of the cortical shell by shrinking the segmentation by 105mm in 3D. Stain volume fraction was calculated as the ratio of BaSO. 4. volume to the sum of BaSO. 4. and bone volume. The L1-L3 motion segments were loaded under axial compression to failure using a µCT compatible loading device (Scanco) and force-displacement data was recorded. µCT scans were acquired unloaded, at 1500µm displacement and post-failure. Stereological analysis was performed on the L2 vertebrae in the unloaded µCT scans. Differences in mean stain volume fraction, mean load to failure, and mean bone volume/total volume (BV/TV) were compared between treatment groups using one-way ANOVAs. Pearson's correlation between stain volume fraction and load to failure by treatment was calculated using an adjusted load to failure divided by BV/TV. Stained damage fraction was significantly different between treatment groups (p=0.0029). Tukey post-hoc analysis showed untreated samples to have higher stain volume fraction (16.25±2.54%) than all treatment groups (p<0.05). The ZA group had the highest mean load to failure (195.60±84.49N), followed by untreated (142.33±53.08N), DTX (126.60±48.75N), and SBRT (95.50±44.96N), but differences did not reach significance (p=0.075). BV/TV was significantly higher in the ZA group (49.28±3.56%) compared to all others. The SBRT group had significantly lower BV/TV than the untreated group (p=0.018). Load divided by BV/TV was not significantly different between groups (p=0.24), but relative load to failure results were consistent (ZA>Untreated>DTX>SBRT). No correlations were found between stain volume fraction and load to failure. Focal and systemic cancer treatments effect microdamage accumulation and load to failure in osteolytic vertebrae. Current testing of healthy controls will help to further separate the effects of the tumour and cancer treatments on bone quality

Aim. Patients with late acute periprosthetic joint infections (PJI) and treated with surgical debridement have a high failure rate. Previous studies have shown that rheumatoid arthritis (RA) is an independent risk factor for treatment failure. We conducted a case-control study to identify predictors for failure in late acute PJI treatment in RA patients. We hypothesize that patients with RA have a higher failure rate compared to controls due to the use of immunosuppressive drugs. Method. Data of an international multicenter retrospective observational study was used. Late acute PJI was defined as a sudden onset of symptoms and signs of a PJI, more than 3 months after implantation. Failure of treatment was defined as persistent signs of infection, relapse with the same or reinfection with a different micro-organism, need for prosthesis removal or death. Cases with RA were matched with cases without RA based on the affected joint. A Cox survival analyses, stratified for RA, was used to calculate hazard ratio's (HR) for failure. Subgroup analyses were used to explore other predictors for treatment failure in RA patients. Results. A total of 40 patients with RA and 80 controls without RA were included. Treatment failure occurred in 65% patients with RA compared to 45% for controls (p= .052). 68% of patients with RA used immunosuppressive drugs at time of PJI diagnosis. The use or continuation of immunosuppressive drugs in PJI was not associated with a higher failure rate; neither were the duration of symptoms and causative microorganism. The time between implantation of the prosthetic joint and diagnosis of infection was longer in RA patients: median 110 (IQR 41-171) vs 29 months (IQR 7.5–101.25). Exchange of mobile components was associated with a lower risk of treatment failure (HR 0.489, 95% CI 0.242–0.989, p-value .047). Conclusions. The use of immunosuppressive drugs does not seem to be associated with a higher failure rate in patients with RA. Mobile exchange in RA patients is associated with a lower risk of failure. This might be due to the significantly older age of the prosthesis in RA patients. Future studies are needed to explore these associations and its underlying pathogenesis

Aim. The most frequent mechanical failure in the osteosynthesis of intertrochanteric fractures is the cut-out. Fracture pattern, reduction quality, tip-apex distance or the position of the cervico-cephalic screw are some of the factors that have been associated with higher cut-out rates. To date, it has not been established whether underlying bacterial colonization or concomitant infection may be the cause of osteosynthesis failure in proximal femur fractures (PFF). The primary objective of this study is to assess the incidence of infection in patients with cut-out after PFF osteosynthesis. Method. Retrospective cohort study on patients with cut-out after PFF osteosynthesis with endomedullary nail, from January 2007 to December 2020. Demographic data of patients (such as sex, age, ASA), fracture characteristics (pattern, laterality, causal mechanism) and initial surgery parameters were collected (time from fall to intervention, duration of surgery, intraoperative complications). Radiographic parameters were also analyzed (tip-apex distance and Chang criteria). In all cut-out cases, 5 microbiological cultures and 1 anatomopathological sample were taken and the osteosynthesis material was sent for sonication. Fracture-related infection (FRI) was diagnosed based on Metsemakers et al (2018) and McNally et al (2020) diagnostic criteria. Results. Of the 67 cut-out cases, 16 (23.9%) presented clinical, analytical or microbiological criteria of infection. Of these sixteen patients, only in 3 of them the presence of an underlying infection was suspected preoperatively. A new osteosynthesis was performed in 24 cases (35.8%) and a conversion to arthroplasty in the remaining 43 (64.2%). A comparative analysis was performed between cases with and without infection. The groups were comparable in terms of demographic data and postoperative radiological data (using Chang criteria and tip-apex distance). Patients with underlying infection had a higher rate of surgical wound complication (56.3% vs 22%, p = 0.014), higher rates of leukocytes counts (11.560 vs 7.890, p = 0.023) and time to surgery (5.88 vs 3.88 days, p = 0.072). Conclusions. One out of four osteosynthesis failure in PFF is due to underlying FRI and in almost 20% were not unsuspected before surgery. In PFF osteosynthesis failures, underlying infection should be taken into account as a possible etiological factor and thus a preoperative and intraoperative infection study should be always performed

Introduction. Debridement, antibiotics irrigation and implant retention (DAIR) is a common management strategy for hip and knee prosthetic joint infections (PJI). However, failure rates remain high, which has led to the development of predictive tools to help determine success. These tools include KLIC and CRIME80 for acute-postoperative (AP) and acute haematogenous (AH) PJI respectively. We investigated whether these tools were applicable to a Waikato cohort. Method. We performed a retrospective cohort study that evaluated patients who underwent DAIR between January 2010 and June 2020 at Waikato Hospital. Pre-operative KLIC and CRIME80 scores were calculated and compared to success of operation. Failure was defined as: (i) need for further surgery, (ii) need for suppressive antibiotics, (iii) death due to the infection. Logistic regression models were used to calculate the area under the curve (AUC). Results. 117 eligible patients underwent DAIR, 53 in the AP cohort and 64 in the AH cohort. Failure rate at 2 years post-op was 43% in the AP cohort and 59% in the AH cohort. In the AP cohort a KLIC score of <4 had a DAIR failure rate of 28.6%, while those who scored ³4 had a failure rate of 72.2% (p=0.002). In the AH cohort a CRIME80 score of <3 had a DAIR failure rate of 48% while those who scored ³3 had a 100% failure rate (p<0.001). Discussion. This study represents the first external validation of the KLIC and CRIME80 scores for predicting DAIR failure in an Australasian population. The results indicate that both KLIC and CRIME80 scoring tools are valuable aids for the clinician seeking to determine the optimal management strategy in patients with AP or AH PJI

Aim. Haematogenous prosthetic joint infections account for 20-35% of total prosthetic infections. Debridement, antibiotics and implant retention (DAIR) is a well-accepted treatment for these infections and probably the most desired by surgeons, since it tries to maintain a functional and stable implant. However, the risk of DAIR failure is not negligible and some risk factors have been described, and also, different scores, such as CRIME80. Nonetheless, less is known about the impact of positive blood cultures may have on DAIR treatment. The aim of our study is to analyze whether the presence of a positive culture is a risk factor for DAIR failure. Method. A retrospective cohort study of 50 late acute haematogenous TKA infections was performed from 2015 to 2023. DAIR failure was defined as the need of a subsequent intervention either a new DAIR or a revision surgery. So, patients were divided into two groups depending on the surgical outcome: successful (SG) vs failure (FG). Demographic variables including age, gender, affected side and body mass index were collected. Patient's comorbidities were also collected including chronic obstructive pulmonary disease (COPD), diabetes, rheumatoid arthritis (RA), cirrhosis and chronic renal failure, etc. Other variables, such as ones included in CRIME80 (C-reactive protein (CRP) >150mg/dl and polyethylene exchange), were also collected. Results. 30 patients had a successful DAIR outcome (60%). Age and sex do not act as risk factors [OR 0.7 (0.2-2.6) and OR 0.4 (0.1-1.3)]. Neither do COPD [OR 3.3 (0.5-2.0), p=0.2]; RA [OR 0.8 (0.2-3.1), p=0.7]; CRP value [3.2 (0.9-11.2), p=0.06]; and polyethylene exchange [OR 0.4 (0.1-2.5), p= 0.3]. Thirty-five blood cultures (70%) were obtained before surgery (20 SG and 15 FG). Nine of the obtained blood cultures were positive (25.7%), being 7 from FG (46.7%) [OR 7.6 (1.3-4.8), p=0.02]. A logistic regression was performed where positive blood cultures were the only significant variable to predict DAIR failure (OR 12, 95% CI 1.1−18, p=0.049), after adjusting for all CRIME80 variables. Skin and soft tissue origin was described in 5 of the nine positive blood cultures (55.6%). Cardiovascular system was the second most common spread (22.2%), and then followed by urogenital and digestive tract. The most common microorganism in FG was Staphylococcus aureus (57.1%) [OR 6.4 (0.2-18.0), p=0.2]. Conclusions. Positive blood cultures may be another risk factor for DAIR failure. This can be important in diagnosis and it may be taken into account in antibiotic and surgical treatment strategies

Background. Anterior cruciate ligament (ACL) reconstruction with concomitant meniscal injury occurs frequently. Meniscal repair is associated with improved long-term outcomes compared to resection but is also associated with a higher reoperation rate. Knowledge of the risk factors for repair failure may be important in optimizing patient outcomes. Purpose. This study aimed to identify the patient and surgical risk factors for meniscal repair failure, defined as a subsequent meniscectomy, following concurrent primary ACL reconstruction. Methods. Data recorded by the New Zealand ACL Registry and the Accident Compensation Corporation, the New Zealand Government's sole funder of ACL reconstructions and any subsequent surgery, was reviewed. Meniscal repairs performed with concurrent primary ACL reconstruction was included. Root repairs were excluded. Univariate and multivariate survival analysis was performed to identify the patient and surgical risk factors for meniscal repair failure. Results. Between 2014 and 2020, a total of 3,024 meniscal repairs were performed during concurrent primary ACL reconstruction (medial repair = 1,814 and lateral repair = 1,210). The overall failure rate was 6.6% (n = 201) at a mean follow-up of 2.9 years, with a failure occurring in 7.8% of medial meniscal repairs (142 out of 1,814) and 4.9% of lateral meniscal repairs (59 out of 1,210). The risk of medial failure was higher in patients with a hamstring tendon autograft (adjusted HR = 2.20, p = 0.001), patients aged 21–30 years (adjusted HR = 1.60, p = 0.037) and in those with cartilage injury in the medial compartment (adjusted HR = 1.75, p = 0.002). The risk of lateral failure was higher in patients aged ≤ 20 years (adjusted HR = 2.79, p = 0.021) and when the procedure was performed by a surgeon with an annual ACL reconstruction case volume of less than 30 (adjusted HR = 1.84, p = 0.026). Conclusion. When performing meniscal repair during a primary ACL reconstruction, the use of a hamstring tendon autograft, younger age and the presence of concomitant cartilage injury in the medial compartment increases the risk of medial meniscal repair failure, whereas younger age and low surgeon volume increases the risk of lateral meniscal repair failure

Aim. D-dimer is a widely available serum test that detects fibrinolytic activities that occur during infection. Prior studies have explored its utility for diagnosis of chronic periprosthetic joint infections (PJI), but not explored its prognostic value for prediction of subsequent treatment failure. The purpose of this study was to: (1) assess the ability of serum D-dimer and other standard-of-care serum biomarkers to predict failure following reimplantation, and (2) establish a new cutoff value for serum D-dimer for prognostic use prior to reimplantation. Method. This prospective study enrolled 92 patients undergoing reimplantation between April 2015 and March 2019 who had previously undergone total hip/knee resection arthroplasty with placement of an antibiotic spacer for treatment of chronic PJI. Serum D-dimer level, erythrocyte sedimentation rate (ESR), and C-reactive protein (CRP) levels were measured preoperatively for all patients. Failure following implantation was defined per the Delphi consensus criteria. Optimal cutoffs for D-dimer, ESR, and CRP were calculated based on ROC curves and compared in their association with failure following reimplantation criteria at minimum 1-year follow-up. Results. 15/92(16.3%) patients failed reimplantation surgery at mean follow up of 2.9 years (range 1.0–4.8). Optimal thresholds for D-Dimer, ESR and CRP were determined to be 1300ng/mL, 30mm/hr, and 1mg/L, respectively. The failure rate in patient with positive D-dimer was significantly higher at 32.0% (8/25) compared to those with negative D-dimer 10.6% (7/66); p=0.024. In comparison, 17.8% (8/45) of patients with ESR above threshold failed, compared to 13.89% (5/41) below (p=0.555) and 16.0% (4/25) of patients with CRP above threshold failed, compared to 16.1% (10/62) below (p=1.000). Conclusions. Patients with elevated D-Dimer appear to be at higher risk of failure after reimplantation surgery. This serum marker may be used to generate an additional data point in patients undergoing reimplantation surgery, especially in circumstances when optimal timing of reimplantation cannot be determined based on clinical circumstances

Aim. Smoking is known to impair wound healing and to increase the risk of peri-operative adverse events and is associated with orthopaedic infection and fracture non-union. Understanding the magnitude of the causal effect on orthopaedic infection recurrence may improve pre-operative patient counselling. Methods. Four prospectively-collected datasets including 1173 participants treated in European centres between 2003 and 2021, followed up to 12 months after surgery for clinically diagnosed orthopaedic infections, were included in logistic regression modelling with Inverse Probability of Treatment Weighting for current smoking status [1–3]. Host factors including age, gender and ASA score were included as potential confounding variables, interacting through surgical treatment as a collider variable in a pre-specified structural causal model informed by clinical experience. The definition of infection recurrence was identical and ascertained separately from baseline factors in three contributing cohorts. A subset of 669 participants with positive histology, microbiology or a sinus at the time of surgery, were analysed separately. Results. Participants were 64% male, with a median age of 60 years (range 18–95); 16% of participants experienced treatment failure by 12 months. 1171 of 1173 participants had current smoking status recorded. As expected for the European population, current smoking was less frequent in older participants (Table 1). There was no baseline association between Charlson score or ASA score and smoking status (p=0.9, p=1, Chi squared test). The estimated adjusted odds ratio for treatment failure at 12 months, resulting from current smoking at the time of surgery, was 1.37 for all participants (95% CI 0.75 to 2.50) and 1.53 for participants with recorded confirmatory criteria (95% CI 1.14 to 6.37). Conclusions. Smoking contributes to infection recurrence, particularly in people with unequivocal evidence of osteomyelitis or PJI. People awaiting surgery for orthopaedic infection should be supported to cease smoking, not only to reduce anaesthetic risk, but to improve treatment outcomes. Limitations of this study include unmeasured socioeconomic confounding and social desirability bias resulting in uncertainty in true smoking status, resulting in underestimated effect size

Hip fractures frequently occur in elderly patients with osteoporosis and are rapidly increasing in prevalence owing to an increase in the elderly population and social activities. We experienced several recent presentations of TFNA nails failed through proximal locking aperture which requires significant revision surgery in often highly co-morbid patient population. The study was done by retrospective data collection from 2013 to 2023 of all the hip fractures which had been fixed with Cephalomedullary nails to review and compare Gamma (2013–2017) and TFNA (2017–2023) failure rates and the timing of the failures. Infected and Elective revision to Arthroplasty cases were excluded. The results are 1034 cases had been included, 784 fixed with TFNA and 250 cases fixed Gamma nails. Out of the 784 patients fixed with TFNA, 19 fixation failed (2.45%). Out of the 250 cases fixed with Gamma nails, 15 fixation failed (6%). Mean days for fixation failure were 323 and 244 days in TFNA and Gamma nails respectively. We conclude that TFNA showed remarkable less failure rates if compared to Gamma nails. At point of launch, testing was limited and no proof of superiority of TFNA over Gamma nail. Several failures identified with proximal locking aperture in TFNA which can be related to the new design which had Substantial reduction in lateral thickness at compression screw aperture

Introduction. IM (Intra Medullary) nail fixation is the standard treatment for diaphyseal femur fractures and also for certain types of proximal and distal femur fractures. Despite the advances in the tribology for the same, cases of failed IM nail fixation continue to be encountered routinely in clinical practice. Common causes are poor alignment or reduction, insufficient fixation and eventual implant fatigue and failure. This study was devised to study such patients presenting to our practice and develop a predictive model for eventual failure. Materials and Methods. 57 patients who presented with failure of IM nail fixation (± infection) between Jan 2011 – Jun 2020 were included in the study and hospital records and imaging reviewed. Those fixed with any other kinds of metalwork were excluded. Classification for failure of IM nails – Type 1: Failure with loss of contact of lag screw threads in the head due to backing out and then rotational instability, Type 2A: Failure of the nail at the nail and lag screw junction, Type 2B: Failure of the screws at the nail lag screw junction, Type 3: Loosening at the distal locking sites with or without infection. X-rays reviewed and causes/site of failure noted. Results. Total patients - 57. Demography - Average age - 58.9 years, 22 Males and 35 females. Eleven patients were noted to have an infection at the fracture site that needed oral or IV antibiotics.16 patients - at least 1 cerclage wire for fracture reduction and fixation + IM Nail. Subtrochanteric fractures (42/57) were the most common to fail. In those fractures with postero-medial comminution, locking of the lag screw in position thus preventing backout can prevent failure. In type 2 failures, preventing varus fixation by early open reduction and temporary fixation with plates and screws can achieve improved results. Those with type 3 failures with periosteal reaction should be considered to be infected until proven otherwise. Conclusions. This classification for failure of IM nails in the femur can be used as a predictive model for failures and allow early recognition and intervention to tackle them

The purpose of this study is to evaluate risk factors for distal construct failure (DCF) in posterior spinal instrumented fusion (PSIF) in adolescent idiopathic scoliosis (AIS). We observed an increased rate of DCF when the pedicle screw in the lowest instrumented vertebra (LIV) was not parallel to the superior endplate of the LIV, however this has not been well studied in the literature. We hypothesise a more inferiorly angled LIV screw predisposes to failure and aim to find the critical angle that predisposes to failure. A retrospective cohort study was performed on all patients who underwent PSIF for AIS at the Starship Hospital spine unit from 2010 to 2020. On a lateral radiograph, the angle between the superior endplate of the LIV was measured against its pedicle screw trajectory. Data on demographics, Cobb angle, Lenke classification, instrumentation density, rod protrusion from the most inferior screw, implants and reasons for revision were collected. Of 256 patients, 10.9% (28) required at least one revision. The rate of DCF was 4.6% of all cases (12 of 260) and 25.7% of revisions were due to DCF. The mean trajectory angle of DCF patients compared to all others was 13.3° (95%CI 9.2° to 17.4°) vs 7.6° (7° to 8.2°), p=0.0002. The critical angle established is 11°, p=0.0076. Lenke 5 and C curves, lower preoperative Cobb angle, titanium only rod constructs and one surgeon had higher failure rates than their counterparts. 9.6% of rods protruding less than 3mm from its distal screw disengaged. We conclude excessive inferior trajectory of the LIV screw increases the rate of DCF and a screw trajectory greater than 11° predisposes to failure. This is one factor that can be controlled by the surgeon intraoperatively and by avoiding malposition of the LIV screw, a quarter of revisions can potentially be eliminated

Introduction. A clinical case of catastrophic ring failure in a 13 year old autistic overweight patient during treatment for tibial lengthening and deformity using a Taylor Spatial Frame is reported. Ring failure was noted during the later stages of bone healing and the frame was removed. The clinical outcome was not affected by the catastrophic ring failure. The photograph of the deformed ring is presented below:. Materials and Methods. The patient's notes and X-rays were reviewed and a macroscopic examination of the deformed ring was performed. Mechanical tests of different Taylor Spatial frame constructs were performed in an attempt to simulate the deformity that was clinically observed. Different constructs of TSF of different ring sizes were fixed to polyurethane cylinders simulating bone, were mechanically tested to failure and load/deflection curves were produced. Results. Macroscopically the ring looked otherwise normal. Gradual mechanical compression tests of Taylor Spatial frame constructs showed that ring deformation increased by increasing the ring diameter and by using jointed rather than full joints without a ring. The ring deformation observed clinically was reproduced at the lab by applying high loads on frame constructs composed of large diameter jointed rings not rigidly fixed to bone. Conclusions. Taylor Spatial frame ring failure during treatment is a serious complication that has not been described in the literature. Possible causes are discussed. Clinicians are advised to use the smaller possible diameter rings. Where large diameter rings are required, these rings should preferably be not jointed. Half rings when used should be carefully and securely joined together by the operating surgeon in order to make a complete ring. For any figures or tables, please contact the authors directly

Aim. One of the surgical therapeutic options for periprosthetic joint infection (PJI) includes debridement, antibiotics, and implant retention (DAIR). Prognostically favorable criteria for DAIR include short duration of symptoms, stable implant, pathogen susceptible to a ‘biofilm-active’ antimicrobial agent, and intact soft-tissue conditions. Despite this, there is a proportion of failures after DAIR, possibly because the duration of infection is underestimated. With the hypothesis that the duration of infection correlates with the bacterial load, and hence, the bacterial load is associated with failure after DAIR, we aimed to investigate the association of bacterial load in the sonication fluid of mobile parts and clinical outcome after DAIR. Method. From our PJI cohort (2010–2021), patients with DAIR (both palliative and curative approaches) were reviewed retrospectively. Patients with hip, knee or shoulder arthroplasties fulfilling infection definition, available sonication results, and ≥2 years follow-up were included. Sonication results were categorized in ≤ or >1000 cfu/mL. Univariate analysis was performed to identify predictors for DAIR failure. Results. Out of 209 PJIs, we identified 96 patients (100 PJIs, 47.8%) with DAIR. In 67 (69.8%) patients with 71 PJIs, there was a follow-up of ≥2 years. The mean age was 72.7 (SD 12.99) years, 50% were male. The infection affected 36 hips (50.7%), 32 knees (45.1%) and 3 shoulders (4.2%). At follow-up, there were 29 (40.8%) cured and 42 (59.2%) failed cases. When comparing failed and cured cases, we found no difference in comorbidities and previously defined risk factors for PJI, ASA score, Charlson score, anatomic location, no. of previous surgeries, pathogenesis of infection or laboratory values. The proportion of patients with high bacterial load on mobile parts (i.e. >1000 cfu/mL) was significantly higher in the failed DAIR group than it was in the cured group (61.9% vs 20.7%, p<0.001). Conclusions. In this study, a high bacterial load in sonication fluid of mobile parts was associated with failure after DAIR in patients with PJI. Sonication may help to differentiate acute hematogenous seeding to the implant and late reactivation of a previously silent implant-associated infection

Meniscal root tears can result from traumatic injury to the knee or gradual degeneration. When the root is injured, the meniscus becomes de-functioned, resulting in abnormal distribution of hoop stresses, extrusion of the meniscus, and altered knee kinematics. If left untreated, this can cause articular cartilage damage and rapid progression of osteoarthritis. Multiple repair strategies have been described; however, no best fixation practice has been established. To our knowledge, no study has compared suture button, interference screw, and HEALICOIL KNOTLESS fixation techniques for meniscal root repairs. The goal of this study is to understand the biomechanical properties of these fixation techniques and distinguish any advantages of certain techniques over others. Knowledge of fixation robustness will aid in surgical decision making, potentially reducing failure rates, and improving clinical outcomes. 19 fresh porcine tibias with intact medial menisci were randomly assigned to four groups: 1) native posterior medial meniscus root (PMMR) (n = 7), 2) suture button (n = 4), 3) interference screw (n = 4), or 4) HEALICOIL KNOTLESS (n = 4). In 12 specimens, the PMMR was severed and then refixed by the specified group technique. The remaining seven specimens were left intact. All specimens underwent cyclic loading followed by load-to-failure testing. Elongation rate; displacement after 100, 500, and 1000 cycles; stiffness; and maximum load were recorded. Repaired specimens had greater elongation rates and displacements after 100, 500, and 1000 cycles than native PMMR specimens (p 0.05). The native PMMR showed greater maximum load than all repair techniques (p 0.05). In interference screw and HEALICOIL KNOTLESS specimens, failure occurred as the suture was displaced from the fixation and tension was gradually lost. In suture button specimens, the suture was either displaced or completely separated from the button. In some cases, tear formation and partial failure also occurred at the meniscus luggage tag knot. Native PMMR specimens failed through meniscus or meniscus root tearing. All fixation techniques showed similar biomechanical properties and performed inferiorly to the native PMMR. Evidence against significant differences between fixation techniques suggests that the HEALICOIL KNOTLESS technique may present an additional option for fixation in meniscal root repairs. While preliminary in vitro evidence suggests similarities between fixation techniques, further research is required to determine if clinical outcomes differ