Aims. Periprosthetic joint infection (PJI) occurs in approximately 1% to 2% of total knee arthroplasties (TKA) presenting multiple challenges, such as difficulty in diagnosis, technical complexity, and financial costs. Two-stage exchange is the gold standard for treating PJI but emerging evidence suggests 'two-in-one' single-stage revision as an alternative, delivering comparable outcomes, reduced morbidity, and cost-effectiveness. This study investigates five-year results of modified single-stage revision for treatment of PJI following TKA with bone loss. Methods. Patients were identified from prospective data on all TKA patients with PJI following the primary procedure. Inclusion criteria were: revision for PJI with bone loss requiring reconstruction, and a minimum five years’ follow-up. Patients were followed up for recurrent infection and assessment of function. Tools used to assess function were Oxford Knee Score (OKS) and American Knee Society Score (AKSS). Results. A total of 24 patients were included with a mean age of 72.7 years (SD 7.6), mean BMI of 33.3 kg/m. 2. (SD 5.7), and median ASA grade of 2 (interquartile range 2 to 4). Mean time from primary to revision was 3.0 years (10 months to 8.3 years). At revision, six patients had discharging sinus and three patients had negative cultures from tissue samples or aspirates. Two patients developed recurrence of infection: one was treated successfully with antibiotic suppression and one underwent debridement, antibiotics, and implant retention. Mean AKSS scores at two years showed significant improvement from baseline (27.1 (SD 10.2 ) vs 80.3 (SD 14.8); p < 0.001). There was no significant change in mean AKSS scores between two and five years (80.3 (SD 14.8 ) vs 74.1 (SD 19.8); p = 0.109). Five-year OKS scores were not significantly different compared to two-year scores (36.17 (SD 3.7) vs 33.0 (SD 8.5); p = 0.081). Conclusion. ‘Two-in-one’ single-stage revision is effective for treating PJI following TKA with bone loss, providing patients with sustained improvements in outcomes and infection clearance up to five years post-procedure. Cite this article: Bone Jt Open 2022;3(2):107–113

Abstract. Introduction. Secondary osteonecrosis of the knee affects young population and causes bilateral extensive lesions. Arthroplasty is the last resort in younger population and joint preserving options questionable in pathological bone. Conservative measures have shown failure in multiple studies and hence no gold standard treatment advocated. We aimed at identifying and analysing various treatment options for secondary osteonecrosis with respect to the outcomes and studying features of symptomatic secondary osteonecrosis with regards to demographic pattern, radiological features and causative factors. Methods. A systematic review of literature was performed in accordance with the Cochrane handbook for systematic reviews and reported according to the PRISMA guidelines. Results. Six studies which included a total of 192 patients with data on 240 knee joints were included in the final review. Follow up period ranged from 1 year to 16 years. The mean age of the patients was 34.7. 3 studies were on arthroplasty and 3 on joint preserving interventions. Majority of patients were in Stage 2 or Stage 4 of osteonecrosis. Steroid induced osteonecrosis was the majority followed by SLE and sickle cell disease. The pooled analysis showed an improvement of pre-operative knee score from 50.47 to 89.21 post-operatively. The pooled effect size for failure rate was 8.7% in joint preserving interventions and 9.2% in joint replacement group. Conclusion. Joint preserving techniques with bone marrow aspirate infiltration showed promising functional outcome and to a certain extent reversal of the pathological process. For advanced stages with subchondral collapse cemented arthroplasty showed satisfactory functional outcomes

Abstract. Purpose. Recently several authors have suggested a correlation between posterior tibial slope (PTS) and sagittal stability of the knee. However, there is a lack of consensus in the literature relating to measurement, normal values and important values to guide treatment. We performed a systematic literature review looking at PTS and cruciate ligament surgery. Our aim was to define a gold standard measurement technique, determine normal ranges and important values for consideration during cruciate ligament surgery. Methods. Electronic searches of MEDLINE (PubMed), CINAHL, Cochrane, Embase, ScienceDirect, and NICE in June 2020 were completed. Inclusion criteria were original studies in peer-reviewed English language journals. A quality assessment of included studies was completed using the Methodological Index for Non-Randomized Studies (MINORS) Criteria. Results. Two-hundred and twenty-one papers were identified; following exclusions 34 papers were included for data collection. The mean MINORS score for non-comparative studies was 13.8 and for comparative studies 20.4, both indicating fair to good quality studies. A large variation in PTS measurement technique was identified, resulting in a wide range of values reported. In addition, there appears to be significant variation between different races, ages and genders. Conclusion. We demonstrated a lack of consensus in the literature relating to various facets of PTS. Cautiously, we suggest normal ranges of 6–12º using the proximal tibia axis at 5 and 15cms below the joint. Potentially 12º is an important cute-off for slope reducing osteotomy as an adjunct to revision ACL reconstruction

Abstract. Introduction. All-tissue quadriceps tendon (QT) is becoming an increasingly popular alternative to hamstrings tendon (HT) and bone-tendon-bone (BTB) autograft for anterior cruciate ligament (ACL) reconstruction. The relatively short graft length however dictates that one, or both, ends rely on suture fixation. The strength of this construct is therefore extremely important. This study evaluates whether the use of a novel fixation technique can improve the tensile properties of the construct compared to a Krackow suture, and a looped tendon (suture free) gold standard. Methods. Eighteen porcine flexor tendons were tested, across three groups; suture-tape Krackow, looped tendon, and the novel ‘strain suture’. Biomechanical testing simulated the different stages of ACL graft preparation and loading (60N preload for 10 minutes, 10 cycles from 10N to 75N, and 1000 cycles from 100N to 400N). Elongation and load to failure were recorded, and stiffness calculated for each construct. Results. The mean elongation was significantly improved for the strain suture compared to the suture tape Krackow for preload, 10 cycle and 1000 cycle testing protocols respectively (1.36mm vs 4.93mm, p<001; 0.60mm vs 2.72mm, p<0.001; 2.95mm vs 29.08mm, p<0.001). Compared with the looped tendon, the strain suture demonstrated similar results for preload and 10 cycle elongation, but greater elongation during the 1000 cycle stage. Stiffness of the latter two constructs was similar. Conclusions. Augmentation of the suture fixation using this novel technique provides a construct that is significantly superior to currently practised suture techniques, and similar in elongation and stiffness to a looped graft

Aims. Periprosthetic joint infection (PJI) is a devastating complication following total knee arthroplasty (TKA). Two-stage revision has traditionally been considered the gold standard of treatment for established infection, but increasing evidence is emerging in support of one-stage exchange for selected patients. The objective of this study was to determine the outcomes of single-stage revision TKA for PJI, with mid-term follow-up. Methods. A total of 84 patients, with a mean age of 68 years (36 to 92), underwent single-stage revision TKA for confirmed PJI at a single institution between 2006 and 2016. In all, 37 patients (44%) were treated for an infected primary TKA, while the majority presented with infected revisions: 31 had undergone one previous revision (36.9%) and 16 had multiple prior revisions (19.1%). Contraindications to single-stage exchange included systemic sepsis, extensive bone or soft-tissue loss, extensor mechanism failure, or if primary wound closure was unlikely to be achievable. Patients were not excluded for culture-negative PJI or the presence of a sinus. Results. Overall, 76 patients (90.5%) were infection-free at a mean follow-up of seven years, with eight reinfections (9.5%). Culture-negative PJI was not associated with a higher reinfection rate (p = 0.343). However, there was a significantly higher rate of recurrence in patients with polymicrobial infections (p = 0.003). The mean Oxford Knee Score (OKS) improved from 18.7 (SD 8.7) preoperatively to 33.8 (SD 9.7) at six months postoperatively (p < 0.001). The Kaplan-Meier implant survival rate for all causes of reoperation, including reinfection and aseptic failure, was 95.2% at one year (95% confidence interval (CI) 87.7 to 98.2), 83.5% at five years (95% CI 73.2 to 90.3), and 78.9% at 12 years (95% CI 66.8 to 87.2). Conclusion. One-stage exchange, using a strict debridement protocol and multidisciplinary input, is an effective treatment option for the infected TKA. This is the largest single-surgeon series of consecutive cases reported to date, with broad inclusion criteria. Cite this article: Bone Jt Open 2021;2(5):305–313

Introduction. Cemented total knee arthroplasty (TKA) remains the gold standard with survivorship above 90% at greater than 10 years postoperatively. However, with younger, heavier, more active patients undergoing TKA at an increasing rate, cementless implants have the appeal of potential for improved implant fixation longevity and decreased rates of aseptic loosening. The cementless implants are more expensive than their cemented counterparts such that implant costs may create a barrier to utilization. However, such comparisons fail to consider the unavoidable additional costs of cementing, including the cost of operating room time, cement and cementing accessories. The purpose of this study is to compare the actual cost of cemented and cementless TKA. Methods. The TKA cost calculation included the cost of operative time, implants, cement and cementing accessories. The difference in operative time between cemented and cementless TKA was determined from a previously published study of 100 TKAs performed using a cemented (55) or press fit (45) implant of the same design performed at a single institution by four fellowship trained arthroplasty surgeons. The decision to use cemented or cementless design in these patients was made based on patient bone quality intraoperatively. Operative time was compared between groups using a Student's two-tailed T-test. The cost of operating room time was based on estimates in the recent literature. The cost of cement and cementing accessories was estimated based on publically available market data. The cost of implants was estimated from institutional data for multiple companies. Results. The cost comparison between cemented and cementless total knee arthroplasty is summarized in Table 1. Mean operative time for cemented TKA was 14.3 minutes longer than for cementless TKA (94.7 + 15.2 vs. 80.4 + 15.7, p<0.01). The estimated cost of one minute of operating room time in the literature ranges from $30 to $60. For our analysis, we used an estimate of $36 per minute obtained from a recently published multi-center study. This resulted in an average operating room time cost $3406 for cemented and $2894 for cementless TKA. Antibiotic cement costs an average of $250 per bag and antibiotic-free cement costs an average of $75 per bag. Cement mixing techniques vary across surgeons. Approximately 95% use a vacuum system and 5% use a mixing bowl. The cost of vacuum systems ranges from $80 for an enclosed bowl to $125 for a vacuum system that can be directly connected to a cement gun. The cost of a plastic mixing bowl and spatula is $20. The cost of the disposables from a cement injection kit is $25. The average cost of a primary TKA implant, including femoral, tibial and polyethylene liner components, is $3530 for cemented and $4659 for cementless designs. Patellar resurfacing is not routinely used at our institution and therefore was not included in implant cost. Based on our calculations, the average cost of a cementless TKA is $7553. Using the cheapest cementing technique with 2 bags of plain cement and a manual mixing bowl with spatula, the cost of a cemented TKA $7114. Using the most expensive cementing technique with 2 bags of antibiotic cement and a cement gun compatible vacuum mixer, the cost of a cemented TKA is $7564. Conclusion. Cemented TKA remains the gold standard and still accounts for most procedures. Cementless TKA is increasing in utilization and may decrease the rate of aseptic loosening, especially in the rapidly growing young, active population undergoing TKA. Although cementless implants remain more expensive than cemented implants at most institutions, the actual overall cost of the two procedures is similar if operative time, cement and cementing accessories are considered. For any figures or tables, please contact authors directly

Introduction. The ideal type of total knee arthroplasty (TKA) prosthesis remains a debatable topic with many different options available. Uncemented TKA has been a viable option due to its decreased operating room (OR) time but also because of its proposed improved long term fixation. Unfortunately, in the past uncemented TKA was associated with increased blood loss. Surgical technique and perioperative treatments have changed since these original studies and tranexamic acid (TXA) has become the gold standard for TKA blood loss management. The objective of this study was to evaluate if there was a difference in hemoglobin and hematocrit change, along with blood loss volume during surgery between cemented and cementless TKA when modern blood loss techniques are utilized. Methods. We retrospectively reviewed data from TKAs performed by three high volume surgeons between 2016 and 2019. We excluded bilateral TKA, revisions, hardware removal intraoperatively and other indications for TKA than primary OA. Power analysis determined 85 patients in both the cementless and cemented TKA groups. Patients were matched 1:1 for age, sex, BMI and surgeon. Use of TXA, intraoperative blood loss, differences in hemoglobin and hematocrit pre- and postoperatively days one, two, and three were recorded. Continuous variables were analyzed using T-tests and categorical variables were evaluated using Chi-squared tests. Results. No significant difference was observed between the cementless and cemented groups for hemoglobin (p=0.214), hematocrit (p=0.164), or intraoperative blood loss volume (p=0.343). A trend towards significantly shorter OR time was seen in the cementless group (p = 0.058). Conclusion. With modern TKA surgery, including the use of TXA, there is no difference in perioperative blood loss between cemented and cementless TKA. Unlike previous studies, the use of modern blood loss salvage techniques in conjunction with cementless TKA fixation, does not result in more blood loss during the perioperative period

Introduction. Manipulation under anesthesia (MUA) remains the gold standard to address restricted range of motion (ROM) within 3–6 months after primary total knee arthroplasty (TKA). However, there is little data on the outcomes of MUA with different types of anesthesia. We sought to compare the outcomes of patients undergoing MUA with intravenous (IV) sedation and neuraxial anesthesia. Methods. We identified 548 MUAs after primary TKA (136 IV sedation, 413 neuraxial anesthesia) at a single institution from 2016–2019. Mean age was 62 years and 349 patients (64%) were female. Mean body mass index was 32 kg/m. 2. The mean time from primary TKA to MUA was 10 weeks. Mean pre-MUA ROM was similar between each group; mean pre-MUA extension was 4.2° (p=0.35) and mean pre-MUA flexion was 77° (p=0.56). Patient demographics were statistically similar between both groups. We compared immediate complications, including fracture, extensor mechanism disruptions, and wound complications, Visual analogue pain scores (VAS), length of stay (LOS), and immediate and 3 month follow-up ROM between these groups. Results. No patients in either group sustained an immediate post-MUA complication. Patients undergoing MUA with IV sedation had significantly higher day of MUA average VAS of 5.1 compared to 4.1 in the neuraxial group (p<0.001). The average LOS was shorter in patients that received IV sedation (9 hours) compared to neuraxial anesthesia (12 hours) (p=0.009). Immediate-post MUA ROM was 1° – 121° in the IV sedation group and 0.9° – 123° in the neuraxial anesthesia group (p=0.21). Three month follow-up ROM was 2° – 108° in the IV sedation group and 1.9° – 110° in the neuraxial anesthesia group. Conclusion. IV sedation and neuraxial anesthesia are both effective anesthetic methods for patients undergoing MUA after primary TKA with minimal perioperative differences. Surgeons and anesthesiologists should cater anesthetic technique to patient specific needs as the orthopedic outcomes are similar for both methods; however, IV sedation resulted in a shorter LOS

Introduction. Two-stage exchange arthroplasty remains the gold standard for treatment of PJI with reported success rates of 85–90%. Complications that occur during treatment are often not reported or considered in the success rate. The purpose of this study was to analyze complications in patients undergoing two-stage exchange and determine when they occur. Methods. We analyzed all patients that underwent two-stage exchange arthroplasty for treatment of chronic PJI of the knee from 2010 to 2018. We categorized complications as medical vs. surgical. The intervals for complications were divided into: interstage, early post re-implant (3 months) and late post re-implant (3 months to minimum 1 year). Minimum follow-up to evaluate complications was one year. Results. Overall, 132 patients underwent a first stage of a two-stage exchange. There were 63 males and 59 females with an average age at first stage surgery of 66.6 years (SD: 8.9). Ten patients (7.6%) did not undergo re-implantation following resection arthroplasty (8 retained spacers and 2 deaths). 122 patients underwent the planned second stage of a two-stage exchange arthroplasty of the knee. The overall success rate (re-implant without recurrence of infection) was 78%. Overall mortality was 1.6% at one year and 9% at 5 years after treatment. Fifty-six patients (46%) experienced at least one complication. 43 patients had an orthopaedic related complication that required additional surgery and 13 patients had a medical complication. 33% of the total complications occurred during the interstage period, 18% within 90 days of reimplant, and 37% greater than three months from reimplant (p=0.0287). Discussion. Reported rates of success of two stage exchanges for PJI have not traditionally considered complications in the definition of success. In our series, significant numbers of patients experienced complications, more often after reimplantation, highlighting the morbidity of this method of treatment and the need for in-depth patient counseling, careful surgical technique, and close follow up. For figures, tables, or references, please contact authors directly

Background. Implant loosening is a common cause of a poor outcome and pain after total knee arthroplasty (TKA). Despite the increase in use of expensive techniques like arthrography, the detection of prosthetic loosening is often unclear pre-operatively, leading to diagnostic uncertainty and extensive workup. The objective of this study was to evaluate the ability of a machine learning (ML) algorithm to diagnose prosthetic loosening from pre-operative radiographs, and to observe what model inputs improve the performance of the model. Methods. 754 patients underwent a first-time revision of a total joint at our institution from 2012–2018. Pre-operative X-Rays (XR) were collected for each patient. AP and lateral X-Rays, in addition to demographic and comorbidity information, were collected for each patient. Each patient was determined to have either loose or fixed prosthetics based on a manual abstraction of the written findings in their operative report, which is considered the gold standard of diagnosing prosthetic loosening. We trained a series of deep convolution neural network (CNN) models to predict if a prosthesis was found to be loose in the operating room from the pre-operative XR. Each XR was pre-processed to segment the bone, implant, and bone-implant interface. A series of CNN models were built using existing, proven CNN architectures and weights optimized to our dataset. We then integrated our best performing model with historical patient data to create a final model and determine the incremental accuracy provided by additional layers of clinical information fed into the model. The models were evaluated by its accuracy, sensitivity and specificity. Results. The CNN we built demonstrated high performance at detecting prosthetic loosening from radiographs alone. Our first model built from scratch on just the image as an input had an accuracy of 70%. Our final model which was built by fine-tuning and optimizing a publicly available model named DenseNet, combining the AP and lateral radiographs, incorporating information from the patient history, had an accuracy, sensitivity, and specificity of 98.5%, 93.9%, and 99.5% on the patients that it was trained on, and an accuracy, sensitivity, and specificity of 88.3%, 70.2%, and 95.6% on the patients it was tested on. Conclusions. The use of machine learning (ML) can accurately detect the presence of prosthetic loosening based on plain radiographs. Its accuracy is progressively enhanced when additional clinical data is added to the loosening analysis algorithm. While this type of machine learning may not be sufficient in its present state of development as a standalone metric of loosening, it is clearly a useful augment for clinical decision making in its present state. Further study and development will be needed to determine the feasibility of applying machine learning as a more definitive test in the clinical setting. For figures, tables, or references, please contact authors directly

Introduction. Tibial component malrotation is associated with pain, stiffness and altered patellofemoral kinematics in total knee arthroplasty (TKA). However, accurately measuring tibial component rotation following TKA is difficult. Proposed protocols utilizing computed tomography (CT) are not well validated and can be time consuming. This study aimed to; 1) Validate and compare the reproducibility of the Berger (2D-CT) and Mayo (3D-CT) protocols; 2) Validate a simple, and potentially rapid screening measurement using an anatomical distance on 2D axial CT- the Centre of Tibial Tray to Tibial Tubercle (CTTT) distance. Methods. Rotational alignment of 70 TKA patients were evaluated by 3 independent observers using the Berger, and Mayo protocols, which have been previously described, and a new CTTT protocol (Figure 1). The inter and intra-rater interclass correlation coefficients (ICC's), mean difference between measurements and the mean measurement times were calculated. Linear regression analysis was performed to give a coefficient of determination (R2). Results. The intra-rater reliability for all 3 protocols was rated as “very good” (Mayo 0.96, Berger 0.85 and CTTT 0.85). The inter-rater reliability for the Mayo and the Berger method was rated as “very good” (0.87 and 0.83 respectively), the CTTT was rated as “good” (0.79). The Mayo method had a lower mean difference in intra-rater measurements than the Berger method (1.42° vs 2.60° p= <0.01). Comparing the CTTT to the Mayo method produced an R2 value of 0.73 indicating strong correlation. As a screening tool, 92% of patients with CTTT ≤ 6mm had < 9° of tibial component internal rotation (IR), and 93% of patients with a CTTT ≥ 10mm had ≥ 9° IR. The Mayo method takes 3 minutes, 29 seconds; Berger method: 2 minutes, 5 seconds; CTTT method: 39 seconds to perform. Conclusion. 3D CT is the gold standard for formally determining tibial component rotational alignment. The CTTT has the strongest correlation to the Mayo method, and is the least time consuming. The CTTT method can be used as a reliable, simple and rapid screening tool in daily clinical practice to assess tibial component rotational alignment following TKA, prior to formal measurement. For any figures or tables, please contact authors directly

Introduction. First generation cephalosporins remain the gold standard perioperative antibiotic for total hip and knee arthroplasty (THA, TKA). However, some patients have documented or self-reported allergies to antibiotics, most commonly penicillin, that result in changes to perioperative antibiotic coverage. Furthermore, patients testing positive for methicillin resistant staphylococcus aureus (MRSA) represent another group where an alternative to cefazolin, typically vancomycin, is often chosen for perioperative prophylaxis. The aims of this study were to 1) characterize the antibiotic choices for perioperative prophylaxis at the time of primary TKA and THA, 2) assess the efficacy of a preoperative antibiotic allergy testing program, and 3) determine rates of periprosthetic joint infection (PJI) based on perioperative antibiotic regimen. Methods. We evaluated all patients undergoing primary TKA or THA at a single academic institution from January 2004-May 2017, yielding a cohort of 29,695 patients. A series of institutional databases were combined to determine which patients underwent antibiotic allergy testing prior to surgery, outcomes from the allergy consultation, perioperative antibiotic management strategy, and survivorship free of infection until final follow-up. Results. Antibiotic allergy testing was performed in 3,411 patients (11.5%) on the basis of a patient provided history of possible penicillin or cephalosporin allergy. Among those tested, 3,310 patients (97.0%) were cleared by the allergist to use cephalosporins in the perioperative period and 2,883 patients (87.1%) eventually received cefazolin. For the entire cohort, 28,174 patients (94.9%) received an operative antibiotic regimen including cefazolin and 1,521 patients (5.1%) received non-cefazolin antibiotics, most commonly vancomycin or clindamycin. Survivorship free of PJI was significantly higher among patients receiving cefazolin compared to non-cefazolin antibiotics with the most rapid divergence occurring within 2 months of surgery (p<0.001) (Figure 1). Survivorship free of PJI in the cefazolin compared to the non-cefazolin groups was 99.40% vs 99.34% at 1 month, 99.11% vs 98.55% at 2 months, 98.83% vs 98.22% at 1 year, and 98.15% vs 96.96% at 10 years (Table 1). Notably, the increased PJI rate observed in the non-cefazolin group was not attributable to high preoperative MRSA prevalence as 0 of the 38 PJIs grew MRSA on culture. The number needed to treat with cefazolin to prevent 1 PJI was 164 patients at 1-year and 84 patients at 10-years. Therefore, potentially 6,098 PJIs could be prevented by 1-year and 11,905 by 10-years in a cohort of 1,000,000 primary TKA and THA patients. Conclusions. This study demonstrates a significantly higher rate of PJI when non-cefazolin antibiotics are used for prophylaxis during primary TKA and THA, which is likely attributable to the superior spectrum of coverage for common PJI organisms compared to vancomycin or clindamycin. This is supported by the increased rate of non-MRSA PJI observed in the non-cefazolin cohort. Furthermore, cefazolin has been shown to act synergistically with vancomycin against MRSA. This work highlights the positive impact of a formal preoperative antibiotic allergy testing program to increase cefazolin usage. Also, surgeons may consider using cefazolin as a dual agent in the case of known MRSA colonization, whenever possible for PJI prophylaxis during TKA and THA. For any figures or tables, please contact authors directly

Aims

The goal was to evaluate tibiofemoral knee joint kinematics during stair descent, by simulating the full stair descent motion in vitro. The knee joint kinematics were evaluated for two types of knee implants: bi-cruciate retaining and bi-cruciate stabilized. It was hypothesized that the bi-cruciate retaining implant better approximates native kinematics.

Aims

Achievement of accurate microbiological diagnosis prior to revision is key to reducing the high rates of persistent infection after revision knee surgery. The effect of change in the microorganism between the first- and second-stage revision of total knee arthroplasty for periprosthetic joint infection (PJI) on the success of management is not clear.

Aims

Sagittal plane imbalance (SPI), or asymmetry between extension and flexion gaps, is an important issue in total knee arthroplasty (TKA). The purpose of this study was to compare SPI between kinematic alignment (KA), mechanical alignment (MA), and functional alignment (FA) strategies.

The purpose of our study was to assess the reproducibility and reliability of traditional radiographic methods of diagnosing trochlear dysplasia compared with the gold standard of MRI. Plain radiographs and MRI scans of 36 knees in 28 patients with proven trochlear dysplasia were compared with 18 controls in a single surgeon's practice. The sulcus angle on MRI and axial radiographs was measured. The lateral radiograph was assessed for adequacy, the crossing sign and the trochlear bump sign. The mean axial (radiograph) and MRI sulcus angles in the dysplastic group were 145° and 158° respectively (p=0.0001) compared to 135° and 138° in the control group (p=0.09). The crossing sign was present in 34 out of 36 lateral radiographs in the dysplastic group and 8 out of 18 in the control group equating to a sensitivity of 94% and specificity of 56%. The quality of the lateral radiograph did not significantly alter the sensitivity or specificity of the crossing sign (p=0.01). The bump sign was present in 22 out of 36 lateral radiographs in the dysplastic group and 1 out of 18 in the control group equating to a sensitivity of 61% and specificity of 94%. Our study shows that an increased radiographic sulcus angle is reliable in diagnosing trochlear dysplasia but underestimates it. The bump sign is a reliable predictor of trochlear dysplasia. The crossing sign is sensitive but not specific in diagnosing dysplasia

Aims

A novel enhanced cement fixation (EF) tibial implant with deeper cement pockets and a more roughened bonding surface was released to market for an existing total knee arthroplasty (TKA) system.This randomized controlled trial assessed fixation of the both the EF (ATTUNE S+) and standard (Std; ATTUNE S) using radiostereometric analysis.

Aims

In cases of severe periprosthetic joint infection (PJI) of the knee, salvage procedures such as knee arthrodesis (KA) or above-knee amputation (AKA) must be considered. As both treatments result in limitations in quality of life (QoL), we aimed to compare outcomes and factors influencing complication rates, mortality, and mobility.

Aims

The diagnosis of periprosthetic joint infection (PJI) can be challenging as the symptoms are similar to other conditions, and the markers used for diagnosis have limited sensitivity and specificity. Recent research has suggested using blood cell ratios, such as platelet-to-volume ratio (PVR) and platelet-to-lymphocyte ratio (PLR), to improve diagnostic accuracy. The aim of the study was to further validate the effectiveness of PVR and PLR in diagnosing PJI.

Aims

Micromotion of the polyethylene (PE) inlay may contribute to backside PE wear in addition to articulate wear of total knee arthroplasty (TKA). Using radiostereometric analysis (RSA) with tantalum beads in the PE inlay, we evaluated PE micromotion and its relationship to PE wear.