A limited number of investigations with conflicting results have described perivascular lymphocytic infiltration (PVLI) in the setting of total knee arthroplasty (TKA). The purpose of this study was to determine if PVLI found in TKAs at the time of aseptic revision surgery was associated with worse clinical outcomes and survivorship. A retrospective review was conducted on 617 patients who underwent aseptic TKA revision who had histological analysis for PVLI at the time of surgery. Clinical and radiological data were obtained pre- and postoperatively, six weeks postoperatively, and then every year thereafter.Aims
Methods
It has been shown that the preoperative modification of risk factors associated with obesity may reduce complications after total knee arthroplasty (TKA). However, the optimal method of doing so remains unclear. The aim of this study was to investigate whether a preoperative Risk Stratification Tool (RST) devised in our institution could reduce unexpected intensive care unit (ICU) transfers and 90-day emergency department (ED) visits, readmissions, and reoperations after TKA in obese patients. We retrospectively reviewed 1,614 consecutive patients undergoing primary unilateral TKA. Their mean age was 65.1 years (17.9 to 87.7) and the mean BMI was 34.2 kg/m2 (SD 7.7). All patients underwent perioperative optimization and monitoring using the RST, which is a validated calculation tool that provides a recommendation for postoperative ICU care or increased nursing support. Patients were divided into three groups: non-obese (BMI < 30 kg/m2, n = 512); obese (BMI 30 kg/m2 to 39.9 kg/m2, n = 748); and morbidly obese (BMI > 40 kg/m2, n = 354). Logistic regression analysis was used to evaluate the outcomes among the groups adjusted for age, sex, smoking, and diabetes.Aims
Methods
The purpose is to determine the non-inferiority of a smartphone-based exercise educational care management system after primary knee arthroplasty compared with a traditional in-person physiotherapy rehabilitation model. A multicentre prospective randomized controlled trial was conducted evaluating the use of a smartphone-based care management system for primary total knee arthroplasty (TKA) and partial knee arthroplasty (PKA). Patients in the control group (n = 244) received the respective institution’s standard of care with formal physiotherapy. The treatment group (n = 208) were provided a smartwatch and smartphone application. Early outcomes assessed included 90-day knee range of movement, EuroQoL five-dimension five-level score, Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) score, 30-day single leg stance (SLS) time, Time up and Go (TUG) time, and need for manipulation under anaesthesia (MUA).Aims
Methods
Liposomal bupivacaine (LB) as part of a periarticular injection protocol continues to be a highly debated topic in total knee arthroplasty (TKA). We evaluated the effect of discontinuing the use of LB in a periarticular protocol on immediate postoperative pain scores, opioid consumption, and objective functional outcomes. On 1 July 2019, we discontinued the use of intraoperative LB as part of a periarticular injection protocol. A consecutive group of patients who received LB as part of the protocol (Protocol 1) and a subsequent group who did not (Protocol 2) were compared. All patients received the same opioid-sparing protocol. Verbal rating scale (VRS) pain scores were collected from our electronic data warehouse and averaged per patient per 12-hour interval. Events relating to the opiate administration were derived as morphine milligram equivalences (MMEs) per patient per 24-hour interval. The Activity Measure for Post-Acute Care (AM-PAC) tool was used to assess the immediate postoperative function.Aims
Methods
The objective of this study is to assess the use of ultrasound (US) as a radiation-free imaging modality to reconstruct 3D anatomy of the knee for use in preoperative templating in knee arthroplasty. Using an US system, which is fitted with an electromagnetic (EM) tracker that is integrated into the US probe, allows 3D tracking of the probe, femur, and tibia. The raw US radiofrequency (RF) signals are acquired and, using real-time signal processing, bone boundaries are extracted. Bone boundaries and the tracking information are fused in a 3D point cloud for the femur and tibia. Using a statistical shaping model, the patient-specific surface is reconstructed by optimizing bone geometry to match the point clouds. An accuracy analysis was conducted for 17 cadavers by comparing the 3D US models with those created using CT. US scans from 15 users were compared in order to examine the effect of operator variability on the output.Aims
Methods
Cementless total knee arthroplasty (TKA) offers the potential for strong biological fixation compared with cemented TKA where fixation is achieved by the mechanical integration of the cement. Few mid-term results are available for newer cementless TKA designs, which have used additive manufacturing (3D printing). The aim of this study was to present mid-term clinical outcomes and implant survivorship of the cementless Stryker Triathlon Tritanium TKA. This was a single institution registry review of prospectively gathered data from 341 cementless Triathlon Tritanium TKAs at four to 6.8 years follow-up. Outcomes were determined by comparing pre- and postoperative Knee Injury and Osteoarthritis Outcome Score for Joint Replacement (KOOS JR) scores, and pre- and postoperative 12-item Veterans RAND/Short Form Health Survey (VR/SF-12) scores. Aseptic loosening and revision for any reason were the endpoints which were used to determine survivorship at five years.Aims
Methods
Debate remains whether the patella should be resurfaced during total knee replacement (TKR). For non-resurfaced TKRs, we estimated what the revision rate would have been if the patella had been resurfaced, and examined the risk of re-revision following secondary patellar resurfacing. A retrospective observational study of the National Joint Registry (NJR) was performed. All primary TKRs for osteoarthritis alone performed between 1 April 2003 and 31 December 2016 were eligible (n = 842,072). Patellar resurfacing during TKR was performed in 36% (n = 305,844). The primary outcome was all-cause revision surgery. Secondary outcomes were the number of excess all-cause revisions associated with using TKRs without (versus with) patellar resurfacing, and the risk of re-revision after secondary patellar resurfacing.Aims
Methods
The aim of this study was to identify the minimal clinically important difference (MCID), minimal important change (MIC), minimal detectable change (MDC), and patient-acceptable symptom state (PASS) threshold in the Forgotten Joint Score (FJS) according to patient satisfaction six months following total knee arthroplasty (TKA). During a one-year period 484 patients underwent a primary TKA and completed preoperative and six-month FJS and OKS. At six months patients were asked, “How satisfied are you with your operated knee?” Their response was recorded as: very satisfied, satisfied, neutral, dissatisfied, or very dissatisfied. The difference between patients recording neutral (n = 44) and satisfied (n = 153) was used to define the MCID. MIC for a cohort was defined as the change in the FJS for those patients declaring their outcome as satisfied, whereas receiver operating characteristic curve analysis was used to determine the MIC for an individual and the PASS threshold. Distribution-based methodology was used to calculate the MDC.Aims
Methods
Many surgeons choose to perform total knee arthroplasty (TKA) surgery with the aid of a tourniquet. A tourniquet is a device that fits around the leg and restricts blood flow to the limb. There is a need to understand whether tourniquets are safe, and if they benefit, or harm, patients. The aim of this study was to determine the benefits and harms of tourniquet use in TKA surgery. We searched MEDLINE, EMBASE, Cochrane Central Register of Controlled trials, and trial registries up to 26 March 2020. We included randomized controlled trials (RCTs), comparing TKA with a tourniquet versus without a tourniquet. Outcomes included: pain, function, serious adverse events (SAEs), blood loss, implant stability, duration of surgery, and length of hospital stay.Aims
Methods
In the last decade, interest in partial knee arthroplasties and bicruciate retaining total knee arthroplasties has increased. In addition, patient-related outcomes and functional results such as range of movement and ambulation may be more promising with less invasive procedures such as bicompartmental arthroplasty (BCA). The purpose of this study is to evaluate clinical and radiological outcomes after a third-generation patellofemoral arthroplasty (PFA) combined with a medial or lateral unicompartmental knee arthroplasty (UKA) at mid- to long-term follow-up. A total of 57 procedures were performed. In 45 cases, a PFA was associated with a medial UKA and, in 12, with a lateral UKA. Patients were followed with validated patient-reported outcome measures (Oxford Knee Score (OKS), EuroQol five-dimension questionnaire (EQ-5D), EuroQoL Visual Analogue Scale (EQ-VAS)), the Knee Society Score (KSS), the Forgotten Joint Score (FJS), and radiological analysis.Aims
Methods
The objective of this study was to compare the two-year migration pattern and clinical outcomes of a total knee arthroplasty (TKA) with an asymmetrical tibial design (Persona PS) and a well-proven TKA with a symmetrical tibial design (NexGen LPS). A randomized controlled radiostereometric analysis (RSA) trial was conducted including 75 cemented posterior-stabilized TKAs. Implant migration was measured with RSA. Maximum total point motion (MTPM), translations, rotations, clinical outcomes, and patient-reported outcome measures (PROMs) were assessed at one week postoperatively and at three, six, 12, and 24 months postoperatively.Aims
Methods
The aim of this study was to measure the effect of hospital case volume on the survival of revision total knee arthroplasty (RTKA). This is a retrospective analysis of Scottish Arthroplasty Project data, a nationwide audit which prospectively collects data on all arthroplasty procedures performed in Scotland. The primary outcome was RTKA survival at ten years. The primary explanatory variable was the effect of hospital case volume per year on RTKA survival. Kaplan-Meier survival curves were plotted with 95% confidence intervals (CIs) to determine the lifespan of RTKA. Multivariate Cox proportional hazards were used to estimate relative revision risks over time. Hazard ratios (HRs) were reported with 95% CI, and p-value < 0.05 was considered statistically significant.Aims
Methods
To estimate the measurement properties for the Oxford Knee Score (OKS) in patients undergoing revision knee arthroplasty (responsiveness, minimal detectable change (MDC-90), minimal important change (MIC), minimal important difference (MID), internal consistency, construct validity, and interpretability). Secondary data analysis was performed for 10,727 patients undergoing revision knee arthroplasty between 2013 to 2019 using a UK national patient-reported outcome measure (PROM) dataset. Outcome data were collected before revision and at six months postoperatively, using the OKS and EuroQol five-dimension score (EQ-5D). Measurement properties were assessed according to COnsensus-based Standards for the selection of health status Measurement Instruments (COSMIN) guidelines.Aims
Methods
Debate continues regarding the optimum management of periprosthetic distal femoral fractures (PDFFs). This study aims to determine which operative treatment is associated with the lowest perioperative morbidity and mortality when treating low (Su type II and III) PDFFs comparing lateral locking plate fixation (LLP-ORIF) or distal femoral arthroplasty (DFA). This was a retrospective cohort study of 60 consecutive unilateral (PDFFs) of Su types II (40/60) and III (20/60) in patients aged ≥ 60 years: 33 underwent LLP-ORIF (mean age 81.3 years (SD 10.5), BMI 26.7 (SD 5.5); 29/33 female); and 27 underwent DFA (mean age 78.8 years (SD 8.3); BMI 26.7 (SD 6.6); 19/27 female). The primary outcome measure was reoperation. Secondary outcomes included perioperative complications, calculated blood loss, transfusion requirements, functional mobility status, length of acute hospital stay, discharge destination and mortality. Kaplan-Meier survival analysis was performed. Cox multivariate regression analysis was performed to identify risk factors for reoperation after LLP-ORIF.Aims
Methods
Meeting preoperative expectations is known to be of major influence on postoperative satisfaction after total knee arthroplasty (TKA). Improved management of expectation, resulting in more realistic expectations can potentially lead to higher postoperative satisfaction. The objective of this study was to assess the effect of an additional preoperative education module, addressing realistic expectations for long-term functional recovery, on postoperative satisfaction and expectation fulfilment. In total, 204 primary TKA patients with osteoarthritis were enrolled in this randomized controlled trial (RCT). Patients were allocated to either usual preoperative education (control group) or usual education plus an additional module on realistic expectations (intervention group). Primary outcome was being very satisfied (numerical rating scale for satisfaction ≥ 8) with the treatment result at 12 months' follow-up. Other outcomes were change in preoperative expectations and postoperative expectation fulfilment.Aims
Methods
Ideal component sizing may be difficult to achieve in unicompartmental knee arthroplasty (UKA). Anatomical variants, incremental implant size, and a reduced surgical exposure may lead to over- or under-sizing of the components. The purpose of this study was to compare the accuracy of UKA sizing with robotic-assisted techniques versus a conventional surgical technique. Three groups of 93 medial UKAs were assessed. The first group was performed by a conventional technique, the second group with an image-free robotic-assisted system (Image-Free group), and the last group with an image-based robotic arm-assisted system, using a preoperative CT scan (Image-Based group). There were no demographic differences between groups. We compared six parameters on postoperative radiographs to assess UKA sizing. Incorrect sizing was defined by an over- or under-sizing greater than 3 mm.Aims
Methods
Total knee arthroplasty (TKA) using functional alignment aims to implant the components with minimal compromise of the soft-tissue envelope by restoring the plane and obliquity of the non-arthritic joint. The objective of this study was to determine the effect of TKA with functional alignment on mediolateral soft-tissue balance as assessed using intraoperative sensor-guided technology. This prospective study included 30 consecutive patients undergoing robotic-assisted TKA using the Stryker PS Triathlon implant with functional alignment. Intraoperative soft-tissue balance was assessed using sensor-guided technology after definitive component implantation; soft-tissue balance was defined as intercompartmental pressure difference (ICPD) of < 15 psi. Medial and lateral compartment pressures were recorded at 10°, 45°, and 90° of knee flexion. This study included 18 females (60%) and 12 males (40%) with a mean age of 65.2 years (SD 9.3). Mean preoperative hip-knee-ankle deformity was 6.3° varus (SD 2.7°).Aims
Methods
A comprehensive classification for coronal lower limb alignment with predictive capabilities for knee balance would be beneficial in total knee arthroplasty (TKA). This paper describes the Coronal Plane Alignment of the Knee (CPAK) classification and examines its utility in preoperative soft tissue balance prediction, comparing kinematic alignment (KA) to mechanical alignment (MA). A radiological analysis of 500 healthy and 500 osteoarthritic (OA) knees was used to assess the applicability of the CPAK classification. CPAK comprises nine phenotypes based on the arithmetic HKA (aHKA) that estimates constitutional limb alignment and joint line obliquity (JLO). Intraoperative balance was compared within each phenotype in a cohort of 138 computer-assisted TKAs randomized to KA or MA. Primary outcomes included descriptive analyses of healthy and OA groups per CPAK type, and comparison of balance at 10° of flexion within each type. Secondary outcomes assessed balance at 45° and 90° and bone recuts required to achieve final knee balance within each CPAK type.Aims
Methods
This study aimed to identify the tibial component and femoral component coronal angles (TCCAs and FCCAs), which concomitantly are associated with the best outcomes and survivorship in a cohort of fixed-bearing, cemented, medial unicompartmental knee arthroplasties (UKAs). We also investigated the potential two-way interactions between the TCCA and FCCA. Prospectively collected registry data involving 264 UKAs from a single institution were analyzed. The TCCAs and FCCAs were measured on postoperative radiographs and absolute angles were analyzed. Clinical assessment at six months, two years, and ten years was undertaken using the Knee Society Knee score (KSKS) and Knee Society Function score (KSFS), the Oxford Knee Score (OKS), the 36-Item Short-Form Health Survey questionnaire (SF-36), and range of motion (ROM). Fulfilment of expectations and satisfaction was also recorded. Implant survivorship was reviewed at a mean follow-up of 14 years (12 to 16). Multivariate regression models included covariates, TCCA, FCCA, and two-way interactions between them. Partial residual graphs were generated to identify angles associated with the best outcomes. Kaplan-Meier analysis was used to compare implant survivorship between groups.Aims
Methods
Patients with a deformity of the hindfoot present a particular challenge when performing total knee arthroplasty (TKA). The literature contains little information about the relationship between TKA and hindfoot alignment. This systematic review aimed to determine from both clinical and radiological studies whether TKA would alter a preoperative hindfoot deformity and whether the outcome of TKA is affected by the presence of a postoperative hindfoot deformity. A systematic literature search was performed in the databases PubMed, EMBASE, Cochrane Library, and Web of Science. Search terms consisted of “total knee arthroplasty/replacement” combined with “hindfoot/ankle alignment”. Inclusion criteria were all English language studies analyzing the association between TKA and the alignment of the hindfoot, including the clinical or radiological outcomes. Exclusion criteria consisted of TKA performed with a concomitant extra-articular osteotomy and case reports or expert opinions. An assessment of quality was conducted using the modified Methodological Index for Non-Randomized Studies (MINORS). The review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines and registered in the PROSPERO database (CRD42019106980).Aims
Methods
For many designs of total knee arthroplasty (TKA) it remains unclear whether cemented or uncemented fixation provides optimal long-term survival. The main limitation in most studies is a retrospective or non-comparative study design. The same is true for comparative trials looking only at the survival rate as extensive sample sizes are needed to detect true differences in fixation and durability. Studies using radiostereometric analysis (RSA) techniques have shown to be highly predictive in detecting late occurring aseptic loosening at an early stage. To investigate the difference in predicted long-term survival between cemented, uncemented, and hybrid fixation of TKA, we performed a randomized controlled trial using RSA. A total of 105 patients were randomized into three groups (cemented, uncemented, and hybrid fixation of the ACS Mobile Bearing (ACS MB) knee system, implantcast). RSA examinations were performed on the first day after surgery and at scheduled follow-up visits at three months, six months, one year, and two years postoperatively. Patient-reported outcome measures (PROMs) were obtained preoperatively and after two years follow-up. Patients and follow-up investigators were blinded for the result of randomization.Aims
Methods
Modern total knee arthroplasty (TKA) prostheses are designed to restore near normal kinematics including high flexion. Kneeling is a high flexion, kinematically demanding activity after TKA. The debate about design choice has not yet been informed by six-degrees-of-freedom in vivo kinematics. This prospective randomized clinical trial compared kneeling kinematics in three TKA designs. In total, 68 patients were randomized to either a posterior stabilized (PS-FB), cruciate-retaining (CR-FB), or rotating platform (CR-RP) design. Of these patients, 64 completed a minimum one year follow-up. Patients completed full-flexion kneeling while being imaged using single-plane fluoroscopy. Kinematics were calculated by registering the 3D implant models onto 2D-dynamic fluoroscopic images and exported for analysis.Aims
Methods
The primary aim of this study was to compare the postoperative systemic inflammatory response in conventional jig-based total knee arthroplasty (conventional TKA) versus robotic-arm assisted total knee arthroplasty (robotic TKA). Secondary aims were to compare the macroscopic soft tissue injury, femoral and tibial bone trauma, localized thermal response, and the accuracy of component positioning between the two treatment groups. This prospective randomized controlled trial included 30 patients with osteoarthritis of the knee undergoing conventional TKA versus robotic TKA. Predefined serum markers of inflammation and localized knee temperature were collected preoperatively and postoperatively at six hours, day 1, day 2, day 7, and day 28 following TKA. Blinded observers used the Macroscopic Soft Tissue Injury (MASTI) classification system to grade intraoperative periarticular soft tissue injury and bone trauma. Plain radiographs were used to assess the accuracy of achieving the planned postioning of the components in both groups.Aims
Methods
Vitamin E-infused highly cross-linked polyethylene (E1) has recently been introduced in total knee arthroplasty (TKA). An in vitro wear simulator study showed that E1 reduced polyethylene wear. However there is no published information regarding in vivo wear. Previous reports suggest that newly introduced materials which reduce in vitro polyethylene wear do not necessarily reduce in vivo polyethylene wear. To assist in the evaluation of the newly introduced material before widespread use, we established an in vivo polyethylene wear particle analysis for TKA. The aim of this study was to compare in vivo polyethylene wear particle generation between E1 and conventional polyethylene (ArCom) in TKA. A total of 34 knees undergoing TKA (17 each with ArCom or E1) were investigated. Except for the polyethylene insert material, the prostheses used for both groups were identical. Synovial fluid was obtained at a mean of 3.4 years (SD 1.3) postoperatively. The in vivo polyethylene wear particles were isolated from the synovial fluid using a previously validated method and examined by scanning electron microscopy.Aims
Methods
The primary aim of this study was to assess whether the postoperative Oxford Knee Score (OKS) demonstrated a ceiling effect at one and/or two years after total knee arthroplasty (TKA). The secondary aim was to identify preoperative independent predictors for patients that achieved a ceiling score after TKA. A retrospective cohort of 5,857 patients undergoing a primary TKA were identified from an established arthroplasty database. Patient demographics, body mass index (BMI), OKS, and EuroQoL five-dimension (EQ-5D) general health scores were collected preoperatively and at one and two years postoperatively. Logistic regression analysis was used to identify independent preoperative predictors of patients achieving postoperative ceiling scores. Receiver operating characteristic curve was used to identify a preoperative OKS that predicted a postoperative ceiling score.Aims
Methods
The aim of this study was to compare robotic arm-assisted bi-unicompartmental knee arthroplasty (bi-UKA) with conventional mechanically aligned total knee arthroplasty (TKA) in order to determine the changes in the anatomy of the knee and alignment of the lower limb following surgery. An analysis of 38 patients who underwent TKA and 32 who underwent bi-UKA was performed as a secondary study from a prospective, single-centre, randomized controlled trial. CT imaging was used to measure coronal, sagittal, and axial alignment of the knee preoperatively and at three months postoperatively to determine changes in anatomy that had occurred as a result of the surgery. The hip-knee-ankle angle (HKAA) was also measured to identify any differences between the two groups.Aims
Methods
Stiffness is a common complication after total knee arthroplasty (TKA). Pathogenesis is not understood, treatment options are limited, and diagnosis is challenging. The aim of this study was to investigate if MRI can be used to visualize intra-articular scarring in patients with stiff, painful knee arthroplasties. Well-functioning primary TKAs (n = 11), failed non-fibrotic TKAs (n = 5), and patients with a clinical diagnosis of fibrosisAims
Methods
Inadvertent soft tissue damage caused by the oscillating saw during total knee arthroplasty (TKA) occurs when the sawblade passes beyond the bony boundaries into the soft tissue. The primary objective of this study is to assess the risk of inadvertent soft tissue damage during jig-based TKA by evaluating the excursion of the oscillating saw past the bony boundaries. The second objective is the investigation of the relation between this excursion and the surgeon’s experience level. A conventional jig-based TKA procedure with medial parapatellar approach was performed on 12 cadaveric knees by three experienced surgeons and three residents. During the proximal tibial resection, the motion of the oscillating saw with respect to the tibia was recorded. The distance of the outer point of this cutting portion to the edge of the bone was defined as the excursion of the oscillating saw. The excursion of the sawblade was evaluated in six zones containing the following structures: medial collateral ligament (MCL), posteromedial corner (PMC), iliotibial band (ITB), lateral collateral ligament (LCL), popliteus tendon (PopT), and neurovascular bundle (NVB).Aims
Methods
The purpose of this study was to develop a personalized outcome prediction tool, to be used with knee arthroplasty patients, that predicts outcomes (lengths of stay (LOS), 90 day readmission, and one-year patient-reported outcome measures (PROMs) on an individual basis and allows for dynamic modifiable risk factors. Data were prospectively collected on all patients who underwent total or unicompartmental knee arthroplasty at a between July 2015 and June 2018. Cohort 1 (n = 5,958) was utilized to develop models for LOS and 90 day readmission. Cohort 2 (n = 2,391, surgery date 2015 to 2017) was utilized to develop models for one-year improvements in Knee Injury and Osteoarthritis Outcome Score (KOOS) pain score, KOOS function score, and KOOS quality of life (QOL) score. Model accuracies within the imputed data set were assessed through cross-validation with root mean square errors (RMSEs) and mean absolute errors (MAEs) for the LOS and PROMs models, and the index of prediction accuracy (IPA), and area under the curve (AUC) for the readmission models. Model accuracies in new patient data sets were assessed with AUC.Aims
Methods
The primary objective of this study was to compare migration of the cemented ATTUNE fixed bearing cruciate retaining tibial component with the cemented Press-Fit Condylar (PFC)-sigma fixed bearing cruciate retaining tibial component. The secondary objectives included comparing clinical and radiological outcomes and Patient Reported Outcome Measures (PROMs). A single blinded randomized, non-inferiority study was conducted including 74 patients. Radiostereometry examinations were made after weight bearing, but before hospital discharge, and at three, six, 12, and 24 months postoperatively. PROMS were collected preoperatively and at three, six, 12, and 24 months postoperatively. Radiographs for measuring radiolucencies were collected at two weeks and two years postoperatively.Aims
Methods
The James Lind Alliance aims to bring patients, carers, and clinicians together to identify uncertainties regarding care. A Priority Setting Partnership was established by the British Association for Surgery of the Knee in conjunction with the James Lind Alliance to identify research priorities related to the assessment, management, and rehabilitation of patients with persistent symptoms after knee arthroplasty. The project was conducted using the James Lind Alliance protocol. A steering group was convened including patients, surgeons, anaesthetists, nurses, physiotherapists, and researchers. Partner organizations were recruited. A survey was conducted on a national scale through which patients, carers, and healthcare professionals submitted key unanswered questions relating to problematic knee arthroplasties. These were analyzed, aggregated, and synthesized into summary questions and the relevant evidence was checked. After confirming that these were not answered in the current literature, 32 questions were taken forward to an interim prioritization survey. Data from this survey informed a shortlist taken to a final consensus meeting.Aims
Methods
The aim of this prospective multicentre study was to describe trends in length of stay and early complications and readmissions following unicompartmental knee arthroplasty (UKA) performed at eight different centres in Denmark using a fast-track protocol and to compare the length of stay between centres with high and low utilization of UKA. We included data from eight dedicated fast-track centres, all reporting UKAs to the same database, between 2010 and 2018. Complete ( > 99%) data on length of stay, 90-day readmission, and mortality were obtained during the study period. Specific reasons for a length of stay of > two days, length of stay > four days, and 30- and 90-day readmission were recorded. The use of UKA in the different centres was dichotomized into ≥ 20% versus < 20% of arthroplasties which were undertaken being UKAs, and ≥ 52 UKAs versus < 52 UKAs being undertaken annually.Aims
Methods
To report mid- to long-term results of Oxford mobile bearing domed lateral unicompartmental knee arthroplasty (UKA), and determine the effect of potential contraindications on outcome. A total of 325 consecutive domed lateral UKAs undertaken for the recommended indications were included, and their functional and survival outcomes were assessed. The effects of age, weight, activity, and the presence of full-thickness erosions of cartilage in the patellofemoral joint on outcome were evaluated.Aims
Methods
Although bone cement is the primary mode of fixation in total knee arthroplasty (TKA), cementless fixation is gaining interest as it has the potential of achieving lasting biological fixation. By 3D printing an implant, highly porous structures can be manufactured, promoting osseointegration into the implant to prevent aseptic loosening. This study compares the migration of cementless, 3D-printed TKA to cemented TKA of a similar design up to two years of follow-up using radiostereometric analysis (RSA) known for its ability to predict aseptic loosening. A total of 72 patients were randomized to either cementless 3D-printed or a cemented cruciate retaining TKA. RSA and clinical scores were evaluated at baseline and postoperatively at three, 12, and 24 months. A mixed model was used to analyze the repeated measurements.Aims
Methods
Total knee arthroplasty is an established treatment for knee osteoarthritis with excellent long-term results, but there remains controversy about the role of uncemented prostheses. We present the long-term results of a randomized trial comparing an uncemented tantalum metal tibial component with a conventional cemented component of the same implant design. Patients under the age of 70 years with symptomatic osteoarthritis of the knee were randomized to receive either an uncemented tantalum metal tibial monoblock component or a standard cemented modular component. The mean age at time of recruitment to the study was 63 years (50 to 70), 46 (51.1%) knees were in male patients, and the mean body mass index was 30.4 kg/m2 (21 to 36). The same cruciate retaining total knee system was used in both groups. All patients received an uncemented femoral component and no patients had their patella resurfaced. Patient outcomes were assessed preoperatively and postoperatively using the modified Oxford Knee Score, Knee Society Score, and 12-Item Short-Form Health Survey questionnaire (SF-12) score. Radiographs were analyzed using the American Knee Society Radiograph Evaluation score. Operative complications, reoperations, or revision surgery were recorded. A total of 90 knees were randomized and at last review 77 knees were assessed. In all, 11 patients had died and two were lost to follow-up.Aims
Methods
While patients with psychological distress have poorer short-term outcomes after total knee arthroplasty (TKA), their longer-term function is unknown. We aimed to 1) assess the influence of preoperative mental health status on long-term functional outcomes, quality of life, and patient satisfaction; and 2) analyze the change in mental health after TKA, in a cohort of patients with no history of mental health disorder, with a minimum of ten years’ follow-up. Prospectively collected data of 122 patients undergoing primary unilateral TKA in 2006 were reviewed. Patients were assessed pre- and postoperatively at two and ten years using the Knee Society Knee Score (KSKS) and Function Score (KSFS); Oxford Knee Score (OKS); and the Mental (MCS) and Physical Component Summary (PCS) which were derived from the 36-Item Short-Form Health Survey questionnaire (SF-36). Patients were stratified into those with psychological distress (MCS < 50, n = 51) and those without (MCS ≥ 50, n = 71). Multiple regression was used to control for age, sex, BMI, Charlson Comorbidity Index (CCI), and baseline scores. The rate of expectation fulfilment and satisfaction was compared between patients with low and high MCS.Aims
Methods
Our objective is to describe our early and mid-term results with the use of a new simple primary knee prosthesis as an articulating spacer in planned two-stage management for infected knee arthroplasty. As a second objective, we compared outcomes between the group with a retained first stage and those with a complete two-stage revision. We included 47 patients (48 knees) with positive criteria for infection, with a minimum two-year follow-up, in which a two-stage approach with an articulating spacer with new implants was used. Patients with infection control, and a stable and functional knee were allowed to retain the initial first-stage components. Outcomes recorded included: infection control rate, reoperations, final range of motion (ROM), and quality of life assessment (QoL) including Western Ontario and McMaster Universities osteoarthritis index, Knee Injury and Osteoarthritis Outcome Score, Oxford Knee Score, 12-Item Short-Form Health Survey questionnaire, and University of California Los Angeles (UCLA) activity score and satisfaction score. These outcomes were evaluated and compared to additional cohorts of patients with retained first-stage interventions and those with a complete two-stage revision. Mean follow-up was 3.7 years (2.0 to 6.5).Aims
Methods
Cementless unicompartmental knee arthroplasty (UKA) has advantages over cemented UKA, including improved fixation, but has a higher risk of tibial plateau fracture, particularly in Japanese patients. The aim of this multicentre study was to determine when cementless tibial components could safely be used in Japanese patients based on the size and shape of the tibia. The study involved 212 cementless Oxford UKAs which were undertaken in 174 patients in six hospitals. The medial eminence line (MEL), which is a line parallel to the tibial axis passing through the tip of medial intercondylar eminence, was drawn on preoperative radiographs. Knees were classified as having a very overhanging medial tibial condyle if this line passed medial to the medial tibial cortex. They were also classified as very small if a size A/AA tibial component was used.Aims
Methods
The purpose of this study was to explore the correlation between femoral torsion and morphology of the distal femoral condyle in patients with trochlear dysplasia and lateral patellar instability. A total of 90 patients (64 female, 26 male; mean age 22.1 years (SD 7.2)) with lateral patellar dislocation and trochlear dysplasia who were awaiting surgical treatment between January 2015 and June 2019 were retrospectively analyzed. All patients underwent CT scans of the lower limb to assess the femoral torsion and morphology of the distal femur. The femoral torsion at various levels was assessed using the a) femoral anteversion angle (FAA), b) proximal and distal anteversion angle, c) angle of the proximal femoral axis-anatomical epicondylar axis (PFA-AEA), and d) angle of the AEA–posterior condylar line (AEA-PCL). Representative measurements of distal condylar length were taken and parameters using the ratios of the bianterior condyle, biposterior condyle, bicondyle, anterolateral condyle, and anteromedial condyle were calculated and correlated with reference to the AEA, using the Pearson Correlation coefficient.Aims
Methods
A significant percentage of patients remain dissatisfied after total knee arthroplasty (TKA). The aim of this study was to determine whether the sequential addition of accelerometer-based navigation for femoral component preparation and sensor-guided ligament balancing improved complication rates, radiological alignment, or patient-reported outcomes (PROMs) compared with a historical control group using conventional instrumentation. This retrospective cohort study included 371 TKAs performed by a single surgeon sequentially. A historical control group, with the use of intramedullary guides for distal femoral resection and surgeon-guided ligament balancing, was compared with a group using accelerometer-based navigation for distal femoral resection and surgeon-guided balancing (group 1), and one using navigated femoral resection and sensor-guided balancing (group 2). Primary outcome measures were Patient-Reported Outcomes Measurement Information System (PROMIS) and Knee injury and Osteoarthritis Outcome (KOOS) scores measured preoperatively and at six weeks and 12 months postoperatively. The position of the components and the mechanical axis of the limb were measured postoperatively. The postoperative range of motion (ROM), haematocrit change, and complications were also recorded.Aims
Methods
Arthrodesis is rarely used as a salvage procedure for patients with a chronically infected total knee arthroplasty (TKA), and little information is available about the outcome. The aim of this study was to assess the reliability, durability, and safety of this procedure as the definitive treatment for complex, chronically infected TKA, in a current series of patients. We retrospectively identified 41 patients (41 TKAs) with a complex infected TKA, who were treated between 2002 and 2016 using a deliberate, two-stage knee arthrodesis. Their mean age was 64 years (34 to 88) and their mean body mass index (BMI) was 39 kg/m2 (25 to 79). The mean follow-up was four years (2 to 9). The extensor mechanism (EM) was deficient in 27 patients (66%) and flap cover was required in 14 (34%). Most patients were host grade B (56%) or C (29%), and limb grade 3 (71%), according to the classification of McPherson et al. A total of 12 patients (29%) had polymicrobial infections and 20 (49%) had multi-drug resistant organisms; fixation involved an intramedullary nail in 25 (61%), an external fixator in ten (24%), and dual plates in six (15%).Aims
Methods
Postoperative range of movement (ROM) is an important measure of successful and satisfying total knee arthroplasty (TKA). Reduced postoperative ROM may be evident in up to 20% of all TKAs and negatively affects satisfaction. To improve ROM, manipulation under anaesthesia (MUA) may be performed. Historically, a limited ROM preoperatively was used as the key harbinger of the postoperative ROM. However, comorbidities may also be useful in predicting postoperative stiffness. The goal was to assess preoperative comorbidities in patients undergoing TKA relative to incidence of postoperative MUA. The hope is to forecast those who may be at increased risk and determine if MUA is an effective form of treatment. Prospectively collected data of TKAs performed at our institution’s two hospitals from August 2014 to August 2018 were evaluated for incidence of MUA. Comorbid conditions, risk factors, implant component design and fixation method (cemented vs cementless), and discharge disposition were analyzed. Overall, 3,556 TKAs met the inclusion criteria. Of those, 164 underwent MUA.Aims
Methods
Rates of readmission and reoperation following primary total knee arthroplasty (TKA) are under scrutiny due to new payment models, which penalize these negative outcomes. Some risk factors are more modifiable than others, and some conditions considered modifiable such as obesity may not be as modifiable in the setting of advanced arthritis as many propose. We sought to determine whether controlling for hypoalbuminaemia would mitigate the effect that prior authors had identified in patients with obesity. We reviewed the American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database for the period of January 2008 to December 2016 to evaluate the rates of reoperation and readmission within 30 days following primary TKA. Multivariate logistic regression modelling controlled for preoperative albumin, age, sex, and comorbidity status.Aims
Methods
In patients with a “dry” aspiration during the investigation of prosthetic joint infection (PJI), saline lavage is commonly used to obtain a sample for analysis. The aim of this study was to investigate prospectively the impact of saline lavage on synovial fluid analysis in revision arthroplasty. Patients undergoing revision hip (THA) or knee arthroplasty (TKA) for any septic or aseptic indication were enrolled. Intraoperatively, prior to arthrotomy, the maximum amount of fluid possible was aspirated to simulate a dry tap (pre-lavage) followed by the injection with 20 ml of normal saline and re-aspiration (post-lavage). Pre- and post-lavage synovial white blood cell (WBC) count, percent polymorphonuclear cells (%PMN), and cultures were compared.Aims
Methods
It has been hypothesized that a unicompartmental knee arthroplasty (UKA) is more likely to be revised than a total knee arthroplasty (TKA) because conversion surgery to a primary TKA is a less complicated procedure. The purpose of this study was to determine if there is a lower threshold for revising a UKA compared with TKA based on Oxford Knee Scores (OKSs) and range of movement (ROM) at the time of revision. We retrospectively reviewed 619 aseptic revision cases performed between December 1998 and October 2018. This included 138 UKAs that underwent conversion to TKA and 481 initial TKA revisions. Age, body mass index (BMI), time in situ, OKS, and ROM were available for all patients.Aims
Methods
The aim of this study was to assess the effectiveness of perioperative essential amino acid (EAA) supplementation to prevent rectus femoris muscle atrophy and facilitate early recovery of function after total knee arthroplasty (TKA). The study involved 60 patients who underwent unilateral TKA for primary knee osteo-arthritis (OA). This was a double-blind, placebo-controlled, randomized control trial with patients randomly allocated to two groups, 30 patients each: the essential amino acid supplementation (9 g daily) and placebo (lactose powder, 9 g daily) groups. Supplementation and placebo were provided from one week before to two weeks after surgery. The area of the rectus femoris muscle were measured by ultrasound imaging one month before surgery and one, two, three, and four weeks postoperatively. The serum albumin level, a visual analogue knee pain score, and mobility were also measured at each time point. The time to recovery of activities of daily living (ADLs) was recorded. Postoperative nutrition and physiotherapy were identical in both groups.Aims
Methods
It remains controversial whether patellofemoral joint pathology is a contraindication to lateral unicompartmental knee arthroplasty (UKA). This study aimed to evaluate the effect of preoperative radiological degenerative changes and alignment on patient-reported outcome scores (PROMs) after lateral UKA. Secondarily, the influence of lateral UKA on the alignment of the patellofemoral joint was studied. A consecutive series of patients who underwent robotic arm-assisted fixed-bearing lateral UKA with at least two-year follow-up were retrospectively reviewed. Radiological evaluation was conducted to obtain a Kellgren Lawrence (KL) grade, an Altman score, and alignment measurements for each knee. Postoperative PROMs were assessed using the Kujala (Anterior Knee Pain Scale) score, Knee Injury and Osteoarthritis Outcome Score Joint Replacement (KOOS JR), and satisfaction levels.Aims
Methods
The integrity of the soft tissue envelope is crucial for successful treatment of infected total knee arthroplasty (TKA). The purpose of this study was to evaluate the rate of limb salvage, infection control, and clinical function following microvascular free flap coverage for salvage of the infected TKA. We retrospectively reviewed 23 microvascular free tissue transfers for management of soft tissue defects in infected TKA. There were 16 men and seven women with a mean age of 61.2 years (39 to 81). The median number of procedures performed prior to soft tissue coverage was five (2 to 9) and all patients had failed at least one two-stage reimplantation procedure. Clinical outcomes were measured using the Knee Society Scoring system for pain and function.Aims
Methods
Metaphyseal cones with cemented stems are frequently used in revision total knee arthroplasty (TKA). However, if the diaphysis has been previously violated, the resultant sclerotic canal can impair cemented stem fixation, which is vital for bone ingrowth into the cone, and long-term fixation. We report the outcomes of our solution to this problem, in which impaction grafting and a cemented stem in the diaphysis is combined with an uncemented metaphyseal cone, for revision TKA in patients with severely compromised bone. A metaphyseal cone was combined with diaphyseal impaction grafting and cemented stems for 35 revision TKAs. There were two patients with follow-up of less than two years who were excluded, leaving 33 procedures in 32 patients in the study. The mean age of the patients at the time of revision TKA was 67 years (32 to 87); 20 (60%) were male. Patients had undergone a mean of four (1 to 13) previous knee arthroplasty procedures. The indications for revision were aseptic loosening (80%) and two-stage reimplantation for prosthetic joint infection (PJI; 20%). The mean follow-up was four years (2 to 11).Aims
Methods
The aim of this study was to determine if the local delivery of vancomycin and tobramycin in primary total knee arthroplasty (TKA) can achieve intra-articular concentrations exceeding the minimum inhibitory concentration thresholds for bacteria causing acute prosthetic joint infection (PJI). Using a retrospective single-institution database of all primary TKAs performed between January 1 2014 and May 7 2019, we identified patients with acute PJI that were managed surgically within 90 days of the initial procedure. The organisms from positive cultures obtained at the time of revision were tested for susceptibility to gentamicin, tobramycin, and vancomycin. A prospective study was then performed to determine the intra-articular antibiotic concentration on postoperative day one after primary TKA using one of five local antibiotic delivery strategies with tobramycin and/or vancomycin mixed into the polymethylmethacrylate (PMMA) or vancomycin powder.Aims
Methods
