Aims. Traditionally, total hip arthroplasty (THA) templating has been performed on anteroposterior (AP) pelvis radiographs. Recently, additional AP hip radiographs have been recommended for accurate measurement of the femoral offset (FO). To verify this claim, this study aimed to establish quantitative data of the measurement error of the FO in relation to leg position and X-ray source position using a newly developed geometric model and clinical data. Methods. We analyzed the FOs measured on AP hip and pelvis radiographs in a prospective consecutive series of 55 patients undergoing unilateral primary THA for hip osteoarthritis. To determine sample size, a power analysis was performed. Patients’ position and X-ray beam setting followed a standardized protocol to achieve reproducible projections. All images were calibrated with the KingMark calibration system. In addition, a geometric model was created to evaluate both the effects of leg position (rotation and abduction/adduction) and the effects of X-ray source position on FO measurement. Results. The mean FOs measured on AP hip and pelvis radiographs were 38.0 mm (SD 6.4) and 36.6 mm (SD 6.3) (p < 0.001), respectively. Radiological view had a smaller effect on FO measurement than inaccurate leg positioning. The model showed a non-linear relationship between projected FO and femoral neck orientation; at 30° external neck rotation (with reference to the detector plane), a true FO of 40 mm was underestimated by up to 20% (7.8 mm). With a neutral to mild external neck rotation (≤ 15°), the underestimation was less than 7% (2.7 mm). The effect of abduction and adduction was negligible. Conclusion. For routine THA templating, an AP pelvis radiograph remains the gold standard. Only patients with femoral neck malrotation > 15° on the AP pelvis view, e.g. due to external rotation contracture, should receive further imaging. Options include an additional AP hip view with elevation of the entire affected hip to align the femoral neck more parallel to the detector, or a CT scan in more severe cases. Cite this article: Bone Jt Open 2022;3(10):795–803

Current estimates of periprosthetic fracture risk associated with femoral implants is mostly limited to revision only estimates and does not accurately represent stem performance. The aim of this study was to estimate the risk of surgically treated post-operative periprosthetic femoral fracture (POPFF) more accurately associated with frequently used femoral implants used for total hip arthroplasty (THA). A cohort study of patients who underwent primary THA in England between January 1, 2004, and December 31, 2020. Periprosthetic fractures were identified from prospectively collected revision records and national procedure coding records. Survival modelling was used to estimate POPFF incidence rates, adjusting for potential confounders. Subgroup analyses were performed for patients over 70 years, with non-osteoarthritic indications, and neck of femur fracture. POPFF occurred in 0.6% (5100/809,832) of cases during a median (IQR) follow up of 6.5 (3.9 to 9.6) years. The majority of POPFF were treated with fixation after implantation of a cemented stem. Adjusted patient time incidence rates (PTIR) for POPFF varied by stem design, regardless of cement fixation. Cemented composite beam stems (CB stems) demonstrated the lowest risk of POPFF. Collared cementless stems had an equivalent or lower rate of POPFF versus the current gold standard polished taper slip cemented stem. POPFF account for a quarter of all revisions following primary THA. Cemented CB stems are associated with the lowest POPFF risk. Stem design is strongly associated with POPFF risk, regardless of the presence of cement. Surgeons, policymakers, and patients should consider these findings when recommending femoral implants in those most at risk of POPFF

Aims. Leg length discrepancy (LLD) is a common pre- and postoperative issue in total hip arthroplasty (THA) patients. The conventional technique for measuring LLD has historically been on a non-weightbearing anteroposterior pelvic radiograph; however, this does not capture many potential sources of LLD. The aim of this study was to determine if long-limb EOS radiology can provide a more reproducible and holistic measurement of LLD. Methods. In all, 93 patients who underwent a THA received a standardized preoperative EOS scan, anteroposterior (AP) radiograph, and clinical LLD assessment. Overall, 13 measurements were taken along both anatomical and functional axes and measured twice by an orthopaedic fellow and surgical planning engineer to calculate intraoperator reproducibility and correlations between measurements. Results. Strong correlations were observed for all EOS measurements (r. s. > 0.9). The strongest correlation with AP radiograph (inter-teardrop line) was observed for functional-ASIS-to-floor (functional) (r. s. = 0.57), much weaker than the correlations between EOS measurements. ASIS-to-ankle measurements exhibited a high correlation to other linear measurements and the highest ICC (r. s. = 0.97). Using anterior superior iliac spine (ASIS)-to-ankle, 33% of patients had an absolute LLD of greater than 10 mm, which was statistically different from the inter-teardrop LLD measurement (p < 0.005). Discussion. We found that the conventional measurement of LLD on AP pelvic radiograph does not correlate well with long leg measurements and may not provide a true appreciation of LLD. ASIS-to-ankle demonstrated improved detection of potential LLD than other EOS and radiograph measurements. Full length, functional imaging methods may become the new gold standard to measure LLD. Cite this article: Bone Jt Open 2022;3(12):960–968

The gold standard treatment of hip dysplasia is a peri-acetabular osteotomy (PAO). Labral tears are seen in the majority of patients presenting with hip dysplasia and diagnosed using Magnetic Resonance Imaging (MRI). The goal was to (1) evaluate utility/value of MRI in patients undergoing hip arthroscopy at time of PAO, and (2) determine whether MRI findings of labral pathology can predict outcome. A prospective randomized controlled trial was conducted at tertiary institutions, comparing patients with hip dysplasia treated with isolated PAO versus PAO with adjunct hip arthroscopy. This study was a subgroup analysis on 74 patients allocated to PAO and adjunct hip arthroscopy (age 26±8 years; 89.2% females). All patients underwent radiographic and MRI assessment using a 1.5-Tesla with or 3-Tesla MRI without arthrography to detect labral or cartilage pathology. Clinical outcome was assessed using international Hip Outcome Tool-33 (iHOT). 74% of patients (55/74) were pre-operatively diagnosed with a labral tear on MRI. Among these, 41 underwent labral treatment (74%); whilst among those without a labral tear on MRI, 42% underwent labral treatment (8/19). MRI had a high sensitivity (84%), but a low specificity (56%) for labral pathology (p=0.053). There was no difference in pre-operative (31.3±16.0 vs. 37.3±14.9; p=0.123) and post-operative iHOT (77.7±22.2 vs. 75.2±23.5; p=0.676) between patients with and without labral pathology on MRI. Value of MRI in the diagnostic work-up of a patient with hip dysplasia is limited. MRI had a high sensitivity (84%), but low specificity (44%) to identify labral pathology in patients with hip dysplasia. Consequently, standard clinical MRI had little value as a predictor of outcome with no differences in PROM scores between patients with and without a labral tear on MRI. Treatment of labral pathology in patients with hip dysplasia remains controversial. The results of this subgroup analysis of a prospective, multi-centre RCT do not show improved outcome among patients with dysplasia treated with labral repair

Hip dysplasia is a common cause of hip pain in young adults. Pelvic osteotomy (PO) techniques are the gold standard for treating symptomatic patients, albeit technically demanding. This study aimed to (1) evaluate the 90-day complication rate, and (2) investigate the reasons, frequency and timing of reoperations following primary PO procedures. We retrospectively analysed the National Hospital Episode Statistics database, examining all patients aged over 14 who underwent PO in NHS England hospitals from 2010 to 2023. We identified index procedures and reoperations using relevant OPCS-4 codes. We analysed patient demographics, 90-day complications, and readmission rates for ipsilateral metalwork removal, revision PO, hip arthroscopy (HA), and THR conversion, and calculated the mean time to reoperations. This study included 1,348 PO cases (mean age: 28.7±9.1 years, 89.5% female). The mean hospital stay was 5.4±3.9 days, with a 90-day readmission rate of 0.52% at a mean of 51.0±17.2 days. The most common causes were infection (0.22%) and reoperation (0.15%). The 90-day rate of pulmonary embolism and deep vein thrombosis was 0.074%. One patient died within 90 days. Overall, 810 patients (60.1%) were readmitted for a subsequent hip procedure at a mean of 2.12±1.90 years following their primary PO. Metalwork removal was required in 616 patients (45.7%) at a mean of 1.70±1.19 years. Readmission rates for revision PO, HA, and THR, were 4.23% (mean time: 2.89±0.82 years), 4.15% (mean time: 2.91±2.28 years) and 6.01% (mean time: 5.24±3.08 years) respectively. This study highlights a low 90-day complication rate following primary PO, but a high reoperation rate, mainly for metalwork removal. We provide the most up-to-date report of revision PO, HA and THR conversion rates in England. These findings provide valuable insight that can facilitate informed decision-making, expectation-setting, and post-operative planning, also establishing a benchmark for future quality improvement

Introduction. Manual chart review is labor-intensive and requires specialized knowledge possessed by highly-trained medical professionals. The cost and infrastructure challenges required to implement this is prohibitive for most hospitals. Natural language processing (NLP) tools are distinctive in their ability to extract critical information from raw text in the electronic health records (EHR). As a simple proof-of-concept, for the potential application of this technology, we examined its ability to discriminate between a binary classification (periprosthetic fracture [PPFFx] vs. no PPFFx) followed by a more complex classification of the same problem (Vancouver). Methods. PPFFx were identified among all THAs performed at a single academic institution between 1977 and 2015. A training cohort (n = 90 PPFFx) selected randomly by an electronic program was utilized to develop a prototype NLP algorithm and an additional randomly-selected 86 PPFFx were used to further validate the algorithm. Keywords to identify, and subsequently classify, Vancouver type PPFFx about THA were defined. The algorithm was applied to consult and operative notes to evaluate language used by surgeons as a means to predict the correct pathology in the absence of a listed, precise diagnosis (e.g. Vancouver B2). Validation statistics were calculated using manual chart review as the gold standard. Results. In distinguishing between 2983 cases of PPFFx, 2898 cases of no PPFFx, and 85 cases of index THA performed for fracture, the NLP algorithm demonstrated an accuracy of 99.8%. Among 73 PPFFx test cases, the algorithm demonstrated a sensitivity of 87.1%, specificity of 78.6%, PPV of 75.0%, and NPV of 89.1% in determining the correct Vancouver classification. Overall Vancouver classification accuracy was moderate at 82.2%. Conclusion. NLP-enabled algorithms are a promising alternative to the current gold standard of manual chart review for evaluating outcomes of large data sets in orthopedics. Despite their immaturity with respect to orthopedic applications, NLP algorithms applied to surgeon notes demonstrated excellent accuracy (99.8%) in delineating a simple binary outcome, in this case the presence or absence of PPFFx. However, accuracy of the algorithm was attenuated when trying to predict a Vancouver classification subtype given the wide variability in surgeon dictation styles and precision of language. Nevertheless, this study provides a proof-of-concept for use of this technology in clinical research and registry development endeavors as it can reliably extract certain select data of interest in an expeditious and cost-effective manner. Summary. NLP-enabled algorithms are a promising alternative to the current gold standard of manual chart review for the extraction and evaluation of large data sets in orthopedics

Aims. Two-stage exchange revision total hip arthroplasty (THA) performed in case of periprosthetic joint infection (PJI) has been considered for many years as being the gold standard for the treatment of chronic infection. However, over the past decade, there have been concerns about its safety and its effectiveness. The purposes of our study were to investigate our practice, collecting the overall spacer complications, and then to analyze their risk factors. Methods. We retrospectively included 125 patients with chronic hip PJI who underwent a staged THA revision performed between January 2013 and December 2019. All spacer complications were systematically collected, and risk factors were analyzed. Statistical evaluations were performed using the Student's t-test, Mann-Whitney U test, and Fisher's exact test. Results. Our staged exchange practice shows poor results, which means a 42% mechanical spacer failure rate, and a 20% recurrent infection rate over the two years average follow-up period. Moreover, we found a high rate of spacer dislocation (23%) and a low rate of spacer fracture (8%) compared to the previous literature. Our findings stress that the majority of spacer complications and failures is reflecting a population with high comorbid burden, highlighted by the American Society of Anesthesiology grade, Charlson Comorbidity Index, and Lee score associations, as well as the cardiac, pulmonary, kidney, or hepatic chronic conditions. Conclusion. Our experience of a two-stage hip exchange revision noted important complication rates associated with high failure rates of polymethylmethacrylate spacers. These findings must be interpreted in the light of the patient’s comorbidity profiles, as the elective population for staged exchange has an increasing comorbid burden leading to poor results. In order to provide better results for this specific population, our conclusion suggests that comparative strategy studies are required to improve our therapeutic indication. Cite this article: Bone Jt Open 2022;3(6):485–494

Background. 80% of health data is recorded as free text and not easily accessible for use in research and QI. Natural Language Processing (NLP) could be used as a method to abstract data easier than manual methods. Our objectives were to investigate whether NLP can be used to abstract structured clinical data from notes for total joint arthroplasty (TJA). Methods. Clinical and hospital notes were collected for every patient undergoing a primary TJA. Human annotators reviewed a random training sample(n=400) and test sample(n=600) of notes from 6 different surgeons and manually abstracted historical, physical exam, operative, and outcomes data to create a gold standard dataset. Historical data collected included pain information and the various treatments tried (medications, injections, physical therapy). Physical exam information collected included ROM and the presence of deformity. Operative information included the angle of tibial slope, angle of tibial and femoral cuts, and patellar tracking for TKAs and approach and repair of external rotators for THAs. In addition, information on implant brand/type/size, sutures, and drains were collected for all TJAs. Finally, the occurrence of complications was collected. We then trained and tested our NLP system to automatically collect the respective variables. Finally, we assessed our automated approach by comparing system-generated findings against the gold standard. Results. Overall, the NLP algorithm performed well at abstracting all variables in our random test dataset (accuracy=96.3%, sensitivity=95.2%, specificity=97.4%). It performed better at abstracting historical information (accuracy=97.0%), physical exam information (accuracy=98.8%), and information on complications (accuracy=96.8%) compared to operative information (accuracy=94.8%), but it performed well with a sensitivity and specificity >90.0% for all variables. Discussion. The NLP system achieved good performance on a subset of randomly selected notes with querying information about TJA patients. Automated algorithms like the one developed here can help orthopedic practices collect information for registries and help guide QI without increased time-burden. For any tables or figures, please contact the authors directly

Aims. To develop a core outcome set of measurements from postoperative radiographs that can be used to assess technical skill in performing dynamic hip screw (DHS) and hemiarthroplasty, and to validate these against Van der Vleuten’s criteria for effective assessment. Methods. A Delphi exercise was undertaken at a regional major trauma centre to identify candidate measurement items. The feasibility of taking these measurements was tested by two of the authors (HKJ, GTRP). Validity and reliability were examined using the radiographs of operations performed by orthopaedic resident participants (n = 28) of a multicentre randomized controlled educational trial (ISRCTN20431944). Trainees were divided into novice and intermediate groups, defined as having performed < ten or ≥ ten cases each for DHS and hemiarthroplasty at baseline. The procedure-based assessment (PBA) global rating score was assumed as the gold standard assessment for the purposes of concurrent validity. Intra- and inter-rater reliability testing were performed on a random subset of 25 cases. Results. In total, 327 DHS and 248 hemiarthroplasty procedures were performed by 28 postgraduate year (PGY) 3 to 5 orthopaedic trainees during the 2014 to 2015 surgical training year at nine NHS hospitals in the West Midlands, UK. Overall, 109 PBAs were completed for DHS and 80 for hemiarthroplasty. Expert consensus identified four ‘final product analysis’ (FPA) radiological parameters of technical success for DHS: tip-apex distance (TAD); lag screw position in the femoral head; flushness of the plate against the lateral femoral cortex; and eight-cortex hold of the plate screws. Three parameters were identified for hemiarthroplasty: leg length discrepancy; femoral stem alignment; and femoral offset. Face validity, content validity, and feasibility were excellent. For all measurements, performance was better in the intermediate compared with the novice group, and this was statistically significant for TAD (p < 0.001) and femoral stem alignment (p = 0.023). Concurrent validity was poor when measured against global PBA score. This may be explained by the fact that they are measuring difference facets of competence. Intra-and inter-rater reliability were excellent for TAD, moderate for lag screw position (DHS), and moderate for leg length discrepancy (hemiarthroplasty). Use of a large multicentre dataset suggests good generalizability of the results to other settings. Assessment using FPA was time- and cost-effective compared with PBA. Conclusion. Final product analysis using post-implantation radiographs to measure technical skill in hip fracture surgery is feasible, valid, reliable, and cost-effective. It can complement traditional workplace-based assessment for measuring performance in the real-world operating room . It may have particular utility in competency-based training frameworks and for assessing skill transfer from the simulated to live operating theatre. Cite this article: Bone Joint Open 2020;1-9:594–604

Two-stage exchange revision total hip arthroplasty performed in case of infection has been considered during many years the gold standard for treatment of chronic infection. Nevertheless, during the last decade, concerns have risen regarding its safety and its efficiency. The purpose of our study was to, first investigate the spacer complications, then to analyze their risks factors. We retrospectively included 125 patients with chronic hip periprosthetic joint infection who underwent a two stage exchange revision arthroplasty performed between January 2013 and December 2019. All spacer complications were systematically collected and risk factors were analyzed. Statistical evaluation were performed using the Student and Mann-Whitney tests. Our study confirms the hypothesis of a high-risk strategy with 42% of patients who had a mechanical spacer failure and a 20% recurrence of infection during the average two years period of follow-up. We found a high rate of spacer migration (23%) and a low rate of spacer fracture (8%) compared to literature. The most important finding was that the majority of spacer complications and failures were found in a population with high medical comorbidities as highlighted by the ASA, Charlson and Lee score associations, as well as with the cardiac, pulmonary, kidney or hepatic chronic conditions. This study showed that a two-stage hip exchange revision is a high-risk procedure regarding complications and mechanical failures of PMMA spacers. In patients with high medical comorbidities, other strategies may be considered and interdisciplinary cooperation with other facilities are needed to identify and control each risk factor

Aims. After failed acetabular fractures, total hip arthroplasty (THA) is a challenging procedure and considered the gold standard treatment. The complexity of the procedure depends on the fracture pattern and the initial fracture management. This study’s primary aim was to evaluate patient-reported outcome measures (PROMs) for patients who underwent delayed uncemented acetabular THA after acetabular fractures. The secondary aims were to assess the radiological outcome and the incidence of the associated complications in those patients. Methods. A total of 40 patients underwent cementless acetabular THA following failed treatment of acetabular fractures. The postoperative clinical and radiological outcomes were evaluated for all the cohort. Results. The median (interquartile range (IQR)) Oxford Hip Score (OHS) improved significantly from 9.5 (7 to 11.5), (95% confidence interval (CI) (8 to 10.6)) to 40 (39 to 44), (95% CI (40 to 43)) postoperatively at the latest follow-up (p < 0.001). It was worth noting that the initial acetabular fracture type (simple vs complex), previous acetabular treatment (ORIF vs conservative), fracture union, and restoration of anatomical centre of rotation (COR) did not affect the final OHS. The reconstructed centre of rotation (COR) was restored in 29 (72.5%) patients. The mean abduction angle in whom acetabular fractures were managed conservatively was statistically significantly higher than the surgically treated patients 42.6° (SD 7.4) vs 38° (SD 5.6)) (p = 0.032). We did not have any case of acetabular or femoral loosening at the time of the last follow-up. We had two patients with successful two-stage revision for infection with overall eight-year survival rate was 95.2% (95% CI 86.6% to 100%) with revision for any reason at a median (IQR) duration of follow-up 50 months (16 to 87) months following THA. Conclusion. Delayed cementless acetabular THA in patients with previous failed acetabular fracture treatments produces good clinical outcomes (PROMS) with excellent survivorship, despite the technically demanding nature of the procedure. The initial fracture treatment does not influence the outcome of delayed THA. In selected cases of acetabular fractures (either nondisplaced or with secondary congruency), the initial nonoperative treatment neither resulted in large acetabular defects nor required additional acetabular reconstruction at the time of THA. Cite this article: Bone Jt Open 2021;2(12):1067–1074

Hip fractures are associated with poor outcomes and high mortality rates of 30%. The current gold standard to measure bone fragility is a Dual-Energy X-ray Absorptiometry (DEXA) scan measuring bone mineral density. Yet DEXA under-diagnoses bone fragility by 50% (1). To combat the burden of bone fragility, this experimental study combined ultrasound (US) with a sophisticated computational algorithm, namely full wave inversion (FWI), to evaluate femoral bone structure. The aims were to assess the association of bone structure between the proximal femoral diaphysis and femoral neck; secondly to evaluate whether transverse ultrasound could assess bone structure of the proximal femoral diaphysis. Bone structure of 19 ex vivo human femora was assessed by micro-CT analysis (mean age 88.11 years, male:female 13:6)(Nikon HMXST 225). Using ImageJ/BoneJ, three 10.2mm subsections of proximal diaphysis and femoral neck underwent analysis: the total bone volume fraction, cortical parameters (bone volume fraction, porosity, thickness) and trabecular parameters (porosity, thickness, spacing and connectivity). A unique US prototype was developed to analyse fifteen femoral diaphyseal subsections using two P4-1 transducers with a novel tomography sequence (Verasonics, Matlab ver R2019a, FWI TRUST protocol). Comparative quantitative analysis of US and Micro-CT measurements was assessed (Graphpad Prism 8.3.1). Micro-CT analysis of the proximal femoral diaphysis demonstrated low correlation to the femoral neck (Pearson r −0.54 to 0.55). US was able to capture cortical structure, though a wide limit of agreement seen when compared to micro-CT analysis (Bland-Altman range 36–59% difference). This novel US technique was able to capture cortical bone structure. Improvements in methodology and technology are required to improve the analysis of trabecular bone and overall accuracy. Further evaluation of US and FWI is required to develop the technique and determine its role in clinical practice

The use of routine sampling for histological analysis during revision hip replacement has been standard practice in our unit for many years. It is used to identify the presence of inflammatory processes that may represent peri-prosthetic infection. This study follows up on a smaller study in the same unit in 2019 where an initial 152 cases were scrutinised. In this follow up study we examined 1,361 consecutive patients over a 16-year period whom had undergone revision hip replacement in a tertiary orthopaedic centre for any reason excluding primary bone tumour or malignant metastasis. All patients had tissue sampling for histopathological analysis performed by consultant histopathologists with a specialist interest in musculoskeletal pathology. The presence of bacteria in greater than 50% of samples sent for microbiological analysis in each patient was used as the gold standard diagnostic comparator for infection. This was then compared with the histology report for each patient. After excluding 219 patients with incomplete data and 1 sample rejection, 1,141 cases were examined. Microbiology confirmed infection in 132 cases (prevalence of infection 11.04%) and histopathology analysis suggested infection in 171 cases. Only 64 cases with confirmed infection in more than 50% of microbiology samples had concurrent diagnosis of infection on histological analysis (5.60% of total; PPV 51.20%). Furthermore, microbiology analysis confirmed infection in 62 cases where histological analysis failed to identify infection (5.43% of total; False negative rate 49.21%). Overall, histopathology analysis was seen to have a good specificity of 93.99% but poor sensitivity of 50.79%. We believe that this is the largest series in the literature and is somewhat unique in that all histology analysis was performed by consultant histopathologists with specialist interest in musculoskeletal pathology. Based on the costs incurred by this additional investigation our experience does not support routine sampling for histological analysis in revision hip arthroplasty. This is a substantial paradigm shift from current practice among revision arthroplasty surgeons in the United Kingdom but would equate to a substantial cost saving

Introduction. Open and arthroscopic hip debridement may be used for treatment of femoral acetabular impingement (FAI). There is a paucity of evidence regarding the efficacy of one over the other. Aim. To compare survivorship in terms of further surgical procedure at five years, in patients having undergone either arthroscopic or open hip debridement. Methods. Using our institutional database, we identified all post learning curve arthroscopic and open hip debridement cases with five years of follow up. Patients were matched based on age, gender and Tonnis grade. The primary outcome measure was 5 year survivorship to total hip arthroplasty (THA). Secondary outcome measures included 5 year survivorship to further (non THA) procedures on the joint. Radiological parameters were analysed including femoral neck version, sourcil, centre-edge and alpha angles. Results. A total of 390 arthroscopic and 1316 open operations were identified. Following exclusion and matching 102 (62 female, 39 male) cases were available for analysis in each group. Mean age was 36 years (range 17–51). At 5 years 14.8% of arthroscopic debridement patients and 5.9% of open debridement patients had undergone THA (p =0 .038). There was no statistical difference in secondary outcome measures. Discussion. A significantly higher percentage of patients undergoing arthroscopic debridement went on to THA when compared to matched patients receiving open debridement. We acknowledge the limitations of this study. However, despite the increasing prevalence of arthroscopic surgery to treat FAI, our results would suggest that open debridement may still remain the gold standard intervention. Further investigation, ideally in the form of an RCT, is warranted. Conclusion. In our case matched series, despite the longer rehabilitation and greater soft tissue insult, open surgery for FAI was associated with significantly less patients progressing to THA within 5 years compared to those undergoing arthroscopic debridement

Introduction. Pre-operative aspiration and culture is the gold standard for the diagnosis of peri-prosthetic infection. This study aimed to ascertain the diagnostic accuracy of culture of joint aspiration with or without saline re-aspiration in the event of a dry-tap. Patients/Materials & Methods. Retrospective analysis of 343 hip aspirations in patients deemed to have moderate-high risk of infection and ultimately proceeded to revision arthroplasty over 12 years at a large quaternary referral centre where pre-operative aspiration is routine. Results. Fluid was aspirated in 141(41%) cases and dry taps in which saline injection-re-aspiration was performed occurred in 202 (59%) cases. Overall sensitivity and specificity of diagnostic aspirate were 82% (74–88%) and 79% (74–84%) respectively. Sensitivity and specificity of saline injection-re-aspiration after dry tap were 79% (64–87%) and 86% (78–92%) compared to 84% (74–91%) and 74% (66–81%) for direct aspiration. Discussion. Pre-operative joint aspiration and culture is a sensitive and specific test for the confirmation of diagnosis in patients at a moderate to high risk of prosthetic joint infection. Culture of saline injection-re-aspiration also provides accurate diagnostic information in the event of a dry tap. Both methods allow susceptibility testing of relevant organisms and are therefore able to guide peri-operative and cement instilled antibiotic therapy. Conclusions. Culture of pre-operative joint aspirates provides sensitive and specific diagnostic information, including antimicrobial susceptibility results. Saline injection-re-aspiration is a useful additional technique in those patients in whom fluid cannot be aspirated

Introduction. Two-stage revision surgery remains the gold standard as treatment for periprosthetic hip infections. The purpose of this study was to determine the rate of infection eradication after two-stage revision hip arthroplasty in patients treated with intraoperatively surgeon-molded articulating spacers as well as to foreshadow the future economical impact of these articulating antibiotic spacers to those commercially available. Methods. Thirty-five patients who underwent two-stage revision hip arthroplasty due to chronic periprosthetic infection between 2003–2014 were followed clinically and radiographically an average of 4.9 years postoperatively [2.2–9.2]. 17 male and 18 female patients with a mean age of 62 [34–82] had articulating spacers, made in the operating room, inserted at the first stage. [The overall expense of the custom-made antibiotic spacers and the commercially available spacers was calculated and compared using a student t test.]. Results. Thirty-one patients (91%) had no clinical or radiographic signs of infection at the time of most recent follow-up. There were no periprosthetic femur fractures and two (6.0%) had a dislocation of hip spacer prior to the second stage surgery. After reimplantation, three patients (9.0%) suffered dislocations of the prosthetic hip, with one of those patients undergoing a second dislocation of the previously reduced hip. [The antibiotic articulating hip spacer manufactured intraoperatively cost $2,712 as compared to commercially available injectable molds $4,619 (p<0.05) and prefabricated spacers $3,820 (p<0.05).]. Conclusions. Patients treated using intraoperatively molded articulating spacers had similar infection eradication rates and outcomes compared to previously reported commercially available articulating spacers1. In the era of cost containment and surgical bundles, surgeon-made articulating spacers should be considered in the first stage of periprosthetic infections. The adjustment in treatment could equate to a national savings of over $12 million annually

Introduction. Fluorodeoxuglucose(FDG) Positron Emission Tomography(PET) scan is used in the diagnosis of prosthetic joint infection, when the inflammatory markers and aspiration of the joint do not establish a definitive diagnosis. The aim of our study was to analyse the utility of FDG PET scan in decision making in these patients. Methods. We performed a prospective study of patients who underwent a FDG PET scan for suspected prosthetic hip infection, between September 2013 and July 2017. We analysed the results of aspiration, culture and sensitivity, histology of intra-operative samples and inflammatory markers. Our gold standard for diagnosis of infection was 3 or more positive cultures of the same organism. Diagnostic utility statistics for FDG PET were performed. Results. 55 revisions total hip replacements were included. The mean age of the patients was 67.5±4.85 years. The mean ESR, CRP and WCC were 19.83 mm/hr, 22.21 mg/l and 9.05×10. 9. /l respectively. The sensitivity and specificity for FDG PET were 93.75% and 35.89% respectively. The positive predictive value(PPV) was 37.5% and negative predictive value(NPV) was 93.33%. The accuracy of detecting an infection was 52.7%. The false positive rate was 62.5%. Discussion. FDG PET has a large number of false positive results and low specificity. If the inflammatory markers and aspiration do not establish infection, addition of FDG PET has limited accuracy in confirming the diagnosis of prosthetic joint infection. Conclusion. FDG PET may be useful for ruling out infection, but a positive result may not indicate the presence of infection

Two-stage reconstruction with total implant removal and re-implantation after infection control is considered the gold standard treatment forinfection after hip arthroplasty. However, removal of the well-fixed stem or cup may cause substantial bone loss and other complications, thereby making reconstruction difficult. We evaluated whether an infection posttotal hip arthroplasty can be treated without removal of the radiographically and clinically well-fixed femoral stem or acetabular cup. Patients with a chronic infection aftertotal hip arthroplasty, with a radiographically well-fixed, cementless stem or cup, were selected. During the first surgical stage, we retained the stem or cup if we were unable to removethese with a stem or cup extractor. An antibiotic-impregnated cement spacer was then implanted. After control of infection (C-reactive proteinlevel within normal value), we performed the secondstage of re-implantation surgery. Treatment failure was defined as uncontrolled infection requiringremoval of the retained implant. From January 2004 to December 2013, 16 patients underwent partial component-retained 2-stage reconstruction. Thirteen patients (81.3%) were free of infection, with a mean follow-up time of 5 years. The remaining 3 patients, who had high-risk comorbidities and, of whom, 2 were infected by high-virulence organism, had uncontrolled infection and required furthersurgery to remove the retained implant. We conclude that partial component-retained 2-stage reconstruction could be an alternative treatment option for chronic infection afteran uncemented total hip arthroplasty with a radiographically and clinically well-fixed component in selected patients, who are notimmunocompromised and are infected by a low-virulence organism

Clinical graphics allows creation of three dimensional simulation based on CT or MRI that allows pre-operative planning. The software reports several hip morphological parameters routinely. Our aim was to validate the measurements of acetabular morphological parameters using CT based clinical graphics in patients presenting with symptomatic hip pain. We reviewed standardised plain radiographs, CT scans and 3D clinical graphics outputs of 42 consecutive hips in 40 patients presenting with symptomatic hip pain. Acetabular index (AI), lateral centre edge angle (LCE), acetabular and femoral version measurements were analysed for the 3D clinical graphics with radiographs and CT as gold standard. Significant differences were noted in measurements of AI, LCE, acetabular version and femoral version using the 3D motion analysis versus conventional measures, with only acetabular version showing comparable measurements. Correlation between 3D clinical graphics and conventional measures of acetabular morphology (AI, LCE) showed only slight agreement (ICC <0.4); while substantial agreement was noted for acetabular and femoral version (IC > 0.5). Acetabular morphological parameters measured by 3D clinical graphics are not reliable or validated. While clinicians may pursue the use of 3D clinical graphics for preoperative non-invasive planning, caution should be exercised when interpreting the reports of hip morphological parameters such as AI and LCE

The gold standard for PJI treatment comprises the use of antibiotic-loaded bone cement spacers, which are limited in their load bearing capacity[1]. Thus, developing an antibiotic-eluting UHMWPE bearing surface can improve the mechanical properties of spacers and improve the quality of life of PJI patients. In this study, we incorporated vancomycin into UHMWPE to investigate its elution characteristics, mechanical properties and its efficacy against an acute PJI in an animal model. Vancomycin hydrochloride was incorporated into UHMWPE (2 to 14%) by blending and consolidation. We studied drug elution with blocks in PBS and UV-Vis spectroscopy at 280 nm. We determined the tensile mechanical properties and impact strength [3]. We implanted osteochondral plugs in rabbits using either control UHMWPE, bone cement (40g) containing vancomycin (1g) and tobramycin (3.6g) or vancomycin-eluting UHMWPE (n=5) plugs in the patellofemoral groove of rabbits. All rabbits received a beaded titanium rod in the tibial canal. All groups received two doses of 5×10. 7. cfu of bioluminescent S. aureus in the distal tibial canal prior to insertion of the rod and the articular space after closure of the joint capsule. No intravenous antibiotics were used. Bioluminescence signal was measured when the rabbits expired, or at 21-day post-op. Hardware, polyethylene implants, and joint tissues were sonicated to further quantify live bacteria via plate seeding. Vancomycin elution increased with increasing drug loading. Vancomycin elution above MIC for 3 weeks and optimized mechanical properties were obtained at 6–7 wt% vancomycin loading in UHMWPE. In our lapine acute infection model using bioluminescent S. aureus, knees treated with UHMWPE without antibiotics and bone cement containing vancomycin and tobramycin had significantly higher bioluminescence compared to those treated with vancomycin-eluting UHMWPE. These results suggest that an antibiotic-eluting UHMWPE spacer with acceptable properties as a bearing surface could be used to treat periprosthetic joint infection in lieu of bone cement spacers and this could allow safer load bearing and a higher quality of life for the patients during treatment. In addition, this presents a safer alternative in cases where the second stage surgery for the implantation of new components is hindered