Abstract. Objective. In this systematic review we aim to analyse the economical impact of using Negative Pressure Wound Therapy (NPWT) in primary total knee arthroplasty (TKA). Methods. Four medical electronic databases were searched. Eligible studies included those investigating the costs of NPWT in primary TKA. Exclusion criteria included studies investigating cost of NPWT not related to primary TKA. We also excluded studies with poor scientific methodology. We retrieved and analysed data on dressing costs and hospital length of stay (LOS). Results. Three studies (359 patients) reported on dressing and associated health care costs, and two further studies (330 patients) reported on hospital LOS in primary TKA. The cost of NPWT ranged between £125 and £196; with an average cost of £155, compared to £23 for the regular surgical dressing. The hospital LOS in NWPT patients ranged from 1.9 – 3.8 days, while LOS in patients managed with regular surgical dressing ranged between 2.3 – 4.7 days. The hospital LOS accounted for delayed discharge due to wound complications. Any extended LOS secondary to medical comorbidities or for other reasons were not included here. Conclusion. Our pooled analysis found a decrease in hospital LOS from wound related problems when using NWPT instead of regular dressings after accounting for other variables responsible for LOS. If the mean cost of overnight inpatient hospital stay for elective TKA is estimated as £275, the range of overnight admission cost for one TKA patient would be £522 - £1045 when NPWT dressing is used, and £632.5 - £1292 when using regular dressings. The cost savings from reduced LOS amounts to £110 - £247 per patient when NPWT is used. We hypothesize that in primary TKA patients with high risk of wound related problems that may delay discharge from hospital, there may be an overall cost saving when using NWPT dressings. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Background. Increasing number of studies investigating surgical patients have reported longer length of stay (LOS) in hospital after an operation with higher ASA grades. However, the impact of Body Mass Index (BMI) on LOS in hospital post Total Knee Replacement (TKR) remains a controversial topic with conflicting findings in reported literature. In our institution, we recently adopted a weight reduction program requiring all patients with raised BMI to participate in order to be considered for elective TKR. Objectives. This has prompted us to investigate the impact BMI has on LOS compared to the more established impact of ASA grade on patients following Primary TKR. Methods. A retrospective analysis was conducted on all elective primary TKR patients between November 2013 and May 2014. LOS was compared in BMI groups <30, 30–40 and >40 and ASA grades 1–2 and 3–4. ANOVA and independent t-test were used to compare mean LOS between BMI groups and ASA grades, respectively. Results. Two hundred and thirty six TKR were analysed. Mean LOS in BMI groups <30, 30–40 and >40 were 6.0, 6.4 and 6.0 days, respectively (p = 0.71). Mean LOS in ASA groups 1–2 and 3–4 were 5.8 and 7.6, respectively (p < 0.01). Conclusions. In patients undergoing primary TKR, ASA grade is a better predictor of LOS than BMI. Our data further adds to the evidence that high BMI alone is not a significant factor in prolonging LOS after a primary TKR. This should be taken into account when allocating resources to optimise patients for surgery. Level of evidence. III - Evidence from case, correlation, and comparative studies

Summary Statement. Pulmonary embolism (PE) after total knee arthroplasty can have a significant impact on patient outcomes and healthcare costs. Efforts to prevent or minimise PE over the last 10 years have not had a significant impact on its occurrence at the national level. Introduction. Pulmonary embolism (PE) is a rare but known potentially devastating complication of total knee arthroplasty (TKA). Significant healthcare resources and pharmaceutical research has been recently focused on preventing this complication but limited data exists regarding the early results of this great effort. The purpose of this study was to assess recent national trends in PE occurrence after TKA and evaluate patient outcomes related to this adverse event. Methods. International Classification of Disease - 9th Revision (ICD-9) procedure codes were used to search the National Hospital Discharge Survey (NHDS) for all patients admitted to US hospitals after primary TKA for each year between 2001 and 2010. ICD-9 diagnosis codes were then used to identify patients from this population who developed an acute PE during the same admission. Data regarding patient demographics, hospitalization length, discharge disposition, deep vein thrombosis, mortality, and hospital size/location were gathered from the NHDS. Trends were evaluated by linear regression with Pearson's correlation coefficient (r) and statistical comparisons were made using Student's t-test, z-test for proportions, and chi-square analysis with a significance level of 0.05. Results. 35,220 patients admitted for a primary TKA were identified. 159 (0.045%) of these patients developed an acute PE during the same admission. After adjusting for fluctuations in annual TKA performed, the development of PE after TKA demonstrated a weak negative correlation with time (r=0.17), insignificantly decreasing from an average rate of 0.049% between 2001–2005 to 0.041% between 2006–2010 (p=0.26). The size of the hospital was found to significantly impact the incidence of PE and primary TKA, with the lowest rate seen in hospitals under 100 beds (0.23%) and the highest rate seen in those with over 500 beds (0.65%, p=0.01). No significant differences in PE incidence were noted based on US region (p=0.38). The mean age of patients with PE was 67.7 years. This group included 54 men and 105 women. The non-PE group had a mean patient age that was insignificantly lower at 66.6 years (p=0.21) and included 12,450 men and 22,611 women. Gender was also not significantly different (p=0.68) between those with PE and those without PE. The number of medical co-morbidities was significantly higher in those with PE (mean 6.42 diagnoses) than those without PE (mean 4.89 diagnoses, p<0.01). Average hospitalization length also varied based on PE status, with significantly longer stays for those with PE (8.2 days, range 2–53) compared to those without PE (3.7 days, range 1–95, p<0.01). The rate of deep vein thrombosis was higher in the PE group (12.7%) versus the non-PE group (0.48%, p<0.01). Mortality was also significantly higher for the PE group (3.9%) compared to the non-PE group (0.09%, p<0.01). Discharge disposition did not significantly vary based on PE status, with 61.5% of PE and 64.0% of non-PE patients able to go directly home (p=0.59) after their inpatient stay. Discussion/Conclusion. This study demonstrates that PE can have a significant impact on patient outcomes and healthcare costs, with an associated 43-fold increase in mortality and a doubling of the inpatient admission duration. Additionally, although the risk of PE after primary TKA remains rare, it still persists. Efforts to prevent or minimise this complication over the last 10 years have not had a significant impact on its occurrence at the national level. This risk of PE appears to be greatest in patients with multiple medical co-morbidities and established DVTs. Interestingly, the PE rate also demonstrated variability based on hospital size. The reasons for this are not clear, but we suspect larger hospitals are more likely to be tertiary-care centers and thus care for more medically-complex patients

Background. The incidence of bleeding following primary TKR has increased with the use of chemical thromboprophylaxis. Our aim was to compare Clexane, Apixaban and Rivaroxaban in terms of frequency and volume of bleeding episodes, need for blood transfusion, return to theatre and incidence of VTE events. Methods. Between February and May 2014, a consecutive series of 132 primary TKRs were studied prospectively. The wound dressings of these patients were assessed daily to look for signs of bleeding and classified into: Mild (< 50p size coin), moderate (> 50p size coin) or Severe (blood seeping through the dressing). Follow up was up to minimum of 30 days post discharge. Results. Apixaban, Rivaroxaban & Clexane were used in 64, 23 and 45 patients respectively. Eleven patients had at least 1 day of mild bleeding, 8 had at least 1 day of moderate bleeding and 11 had at least 1 day of severe bleeding. Ten patients had 1 or more doses omitted because of bleeding. However, there was no statistical significance in distribution of bleeding episodes or doses omitted due to bleeding amongst the three drugs (chi squared test). There was also no correlation between number of severe bleeding episodes and the need for blood transfusion. There were two VTE events recorded; 1 PE each in the Apixaban and Rivaroxaban groups. Two cases in the Apixaban group and 1 case in the Clexane group returned to theatre for washout of haematoma. Conclusion. There was an 8% incidence of severe bleeding in our study group. The incidence of bleeding problems following TKR was similar in the Apixaban, Rivaroxaban & Clexane groups. Level of evidence. III - Evidence from case, correlation, and comparative studies

Background. Acute pain following total knee replacements (TKRs) is associated with higher peri-operative opiate requirements and their side effects, longer hospital stay and lower patient satisfaction (Petersen 2014). It may also be associated with higher rates of chronic pain at 1 and 5 years (Beswick 2012). We present a novel technique using combination of Local Infiltration Anaesthesia (LIA) with PainKwell infusion system (Bupivacaine 0.5 @ 4mls and 6mls/hr) to improve pain management following TKRs. Methods. Between October 2015 and March 2016. 110 patients undergoing primary TKR were prospectively studied. All patients studied had spinal anaesthesia (SA) with diamorphine. Demographics between the two groups were similar. Group 1. SA plus LIA plus traditional multimodal analgesia. 32 patients. Group 2. SA plus LIA plus PainKwell for 48 hours rate 4mls. 38 patients. Group 3. SA plus LIA plus PainKwell for 48 hours rate 6mls. 40 patients. Results. Visual analogue pain scores demonstrated a significant difference at 8hrs, 12hrs, 24hrs and 48hrs between group 1 and 3; p<0.05. There was also a statistical difference in opiate usage at 24 hours between the three groups with group 3 using significantly less opiates compared to group 1. There was least consumption of opiates in group 3 patients across all study periods. Conclusions. This study reported that SA plus LIA and PainKwell system was effective in reducing pain following TKRs. It also demonstrated that the technique of SA plus LIA plus PainKwell for 48 hours at a rate 6mls/hr reduced opiate usage by 50% and pain by 30% for these patients. Implications. This technique may help improve rehabilitation and shorten hospital stay following total knee arthroplasties

Background. Despite an ageing population and a rise in the number of joint replacements being performed, the mean age of patients undergoing surgery remains static. One explanation for this is continued concern over the risks of performing surgery on the very elderly. We aim to investigate the outcome of Total Knee Replacement (TKR) in a nonagenarian population. Methods. The Elective Orthopaedic Centre, Epsom has an established patient reported outcome measures (PROMs) programme into which all patients are routinely enrolled. We retrospectively reviewed our data set for a cohort of nonagenarians undergoing primary TKR, between April 2008 and October 2011. Post-operative complications, mortality rates and functional outcomes were compared to those of a time matched 70–79 year old cohort. Only patients with a primary diagnosis of osteoarthritis were included whereas an exclusion criterion consisted of patients undergoing revision surgery, simultaneous bilateral replacements or conversion from a Unicompartmental Knee replacement. Results. We identified 31 nonagenarian patients, with a mean age of 91.0 (90–96) and the control group consisted of 36 patients, with a mean age of 74.5 (70–79). Following a TKR, the nonagenarian cohort achieved a lower mean Oxford Knee Score (OKS) at 1 year (31.7+/−9.5) (p=0.15), but no difference existed by 2 years (p=0.157), and a mean outcome satisfaction of 85.2% (+/− 22.75) at 1 year, which was similar to the younger group. The nonagenarians had a greater risk of requiring a blood transfusion following a TKR (p=0.0373; CI 1.08 to 16.65), and a longer length of stay than their younger counterparts (p=0.001). Mortality rates were higher in the nonagenarian cohort, but these were in keeping with the life expectancy projections identified by the Office for National Statistics. Conclusion. In conclusion, we identified that over a 2 year period, nonagenarians achieved the same functional outcome and satisfaction rates following a TKR as 70–79 year olds. Level of Evidence IV

Background

Tranexamic acid (TXA) and fibrin sealants have gained widespread use in total knee arthroplasty. They can decrease bleeding, drainage volume, hematoma formation, and incidence of blood transfusion. However, they are costly and carry a theoretical risk of infection transmission and thrombosis. This study compares the two pharmacologic interventions to preoperative autologous blood donation as well as no intervention.

Introduction

Better functional outcomes, lower pain and better stability have been reported with knee designs which restore physiological knee kinematics. Also the ability of the TKA design to properly restore the physiological femoral rollback during knee flexion, has shown to be correlated with better restoration of the flexor/extensor mechanism, which is fundamental to the function of the human knee. The purpose of the study is to compare the kinematics of three different TKA designs, by evaluating knee motion during Activities of Daily Living. The second goal is to see if there is a correlation between the TKA kinematics and the patient reported outcomes.

Fixed flexion contracture (FFC) following total knee arthroplasty (TKA) is a source of morbidity for patients. This retrospective review of pre- and post-operative data for 811 total knee replacements with two year follow up aimed to identify pre-operative risk factors for developing FFC and quantify the effect of FFC on outcomes. The incidence of FFC two years post-operation was 3.6%. Advanced age was associated with increased rate of FFC (p=0.02) Males were 2.6 times more likely than females to have FFC at two years (p=0.012). Patients with pre-implant FFC were 2.95 times more likely than those without to have FFC (p=0.028). BMI was not a risk factor (p=0.968). Patients with FFC had poorer outcomes (Oxford Knee Score p=0.003, patient satisfaction p=0.036). The results of this study support the existing literature and clarify a previously contentious point by excluding BMI as a risk factor.

To compare the efficacy of intra-articular and intravenous modes of administration of tranexamic acid in primary total knee arthroplasty in terms of blood loss and fall in haemoglobin level. Study Design: Randomized controlled trial. Duration of Study: Six months, from May 2019 to Nov 2019. Seventy-eight patients were included in the study. All patients undergoing unilateral primary total knee replacement were included in the study. Exclusion criteria were patients with hepatitis B and C, history of previous knee replacement, bilateral total knee replacement, allergy to TXA, Hb less than 11g/dl in males and less than 10g/dl in females, renal dysfunction, use of anticoagulants for 7 days prior to surgery and history of thromboembolic diseases. Patients were randomly divided into group A and B. Group A patients undergoing unilateral primary total knee replacement (TKR) were given intravenous tranexamic acid (TXA) while group B were infiltrated with intra-articular TXA. Volume of drain output, fall in haemoglobin (Hb) level and need for blood transfusion were measured immediately after surgery and at 12 and 24 hours post operatively in both groups. The study included 35 (44.87%) male and 43 (55.13%) female patients. Mean age of patients was 61 ± 6.59 years. The mean drain output calculated immediately after surgery in group A was 45.38 ± 20.75 ml compared with 47.95 ± 23.86 ml in group B (p=0.73). At 24 hours post operatively, mean drain output was 263.21 ± 38.50 ml in intravenous group versus 243.59 ± 70.73 ml in intra-articular group (p=0.46). Regarding fall in Hb level, both groups showed no significant difference (p>0.05). About 12.82% (n=5) patients in group A compared to 10.26% (n=4) patients required blood transfusion post operatively (p=0.72). Intra-articular and intravenous TXA are equally effective in patients undergoing primary total knee arthroplasty in reducing post-operative blood loss

Introduction and Objective. Difficult primary total knee arthroplasty (TKA) and revision TKA are high demanding procedures. Joint exposure is the first issue to face off, in order to achieve a good result. Aim of this study is to evaluate the clinical and radiological outcomes of a series of patients, who underwent TKA and revision TKA, where tibial tubercle osteotomy (TTO) was performed. Materials and Methods. We retrospectively reviewed a cohort of 79 consecutives TKAs where TTO was performed, from our Institution registry. Patients were assessed clinically and radiographically at their last follow-up (mean, 7.4 ± 3.7 years). Clinical evaluation included the Knee Society Score (KSS), the pain visual analogue scale (VAS), and range of motion. Radiological assessment included the evaluation of radiolucent lines, osteolysis, cortical bone hypertrophy, time of bone healing of the TTO fragment, and the hardware complication. Results. KSS raised from 40.7 ± 3.1 to 75 ± 4.3 (p < 0.0001). Knee flexion increased from 78.7 ± 9.9° to 95.0 ± 9.5° (p < 0.0001), and VAS improved from 7.9 ± 0.9 to 3.8 ± 1 (p < 0.0001). No signs of loosening or evolutive radiolucency lineswere found. Osteolytic areas around the stem were detected. No significant association was found between the implant design and the outcomes, while aseptic loosening showed significantly better results. Complications were: 4 painful hardware, 3 late periprosthetic infections, 1 extension lag of 5°, and 3 flexion lag. Conclusions. Our experience suggests the use of TTO to improve the surgical approach in difficult primary TKA or revision TKA. A strict surgical technique leads to good results with low risk of complications

Abstract. Objective. In this systematic review we aim to compare wound complication rates from Negative Pressure Wound Therapy (NPWT) to dry sterile surgical dressings in primary and revision total knee arthroplasty (TKA). Methods. A search was performed using PubMed, Embase, Science Direct, and Cochrane Library. Eligible studies included those investigating the use of NPWT in primary and revision TKA. Exclusion criteria included studies investigating NPWT not related to primary or revision TKA; studies in which data relating to NPWT was not accessible; missing data; without an available full text, or not well reported. We also excluded studies with poor scientific methodology. All publications were limited to the English language. Abstracts, case reports, conference presentations, and reviews were excluded. Welch independent sample t-test was used for the statistical analysis. Results. Our review identified 11 studies evaluating 1,414 patients. Of the 1,181 primary TKA patients analysed (NPWT = 416, surgical dressing = 765), the overall wound complication rates in patients receiving NPWT ranged from 0% – 63% (Median 7.30%, SD ± 21.44) This is in comparison to complication rates of 2.8% – 19% (Median 6.50%, SD ± 6.59) in the dry dressing group. The difference in complication rates between the two groups was not statistically significant (p =0.337). In the revision TKA cohort of 279 patients (NPWT group = 128, dry dressing group = 151), the overall wound complication rates in the NPWT group ranged between 6.7% – 12% (Median 9.80%, SD ± 2.32) vs 23.8% – 30% (Median 26.95%, SD ± 2.53) in the dry dressing group. This difference was statistically significant (p<0.001). Conclusion. NPWT dressing demonstrated statistically significant reduction in wound complication rates when used in revision TKA but not primary TKA when compared to dry sterile dressings. This is probably due to higher wound related risks encountered with revision TKA surgery compared to primary TKA surgery. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

To determine risk factors of infection in total knee arthroplasty. This descriptive study was conducted in the Department of Orthopedics for a duration of three years from January 2016 to January 2019. All patients undergoing primary total knee replacement were included in the study. Exclusion criteria were all patients operated in another hospital and revision total knee replacement. All patients were followed up at 2, 4, 8, 12 and 24 weeks post-operatively. Signs of inflammation and inflammatory markers such as total leukocyte count (TLC), C-reactive protein (CRP) and ESR were measured. Risk factors like age, body mass index (BMI), ASA, co-morbid conditions were also noted. A total of 78 patients underwent primary unilateral Total Knee Replacement (TKR) during the study period. Of these, 30 (34.09%) were male and 48 (61.54%) female patients. Mean age of patients was 68.32 ± 8.54 years. Average BMI 25.89 Kg/m2 .Osteoarthritis was the pre-dominant cause of total knee replacement (94.87%). Among co-morbid factors 33.33% were diabetic, 28.20% having ischemic heart disease and 12.82% with chronic lung disease. Upon anaesthesia fitness pre-operatively, 91.02% patients had an American society of anaesthesiologist score (ASA) between 0–2 while 07 (8.97%) between 3- 5. Average duration of surgery was 85.62± 4.11 minutes. 6.41% cases got infected. In majority of the infected cases (60%), Staphylococcus aureus was the infective organism. Diabetes Mellitus (p=0.01) and Obesity (p=0.02) had a significant relation to post-operative infection. Pre-operative risk evaluation and prevention strategies along with early recognition of infection and control can greatly reduce the risk of joint infection post-TKR which will not only improve the mobility of patient but also its morbidity and mortality as well. Key Words:. C-reactive protein (CRP), Erythrocyte Sedimentation Rate (ESR), Staphylococcus aureus, Total Knee Arthroplasty (TKA)

Abstract. Approximately 20% of primary and revision Total Knee Arthroplasty (TKA) patients require multiple revisions, which are associated with poor survivorship, with worsening outcomes for subsequent revisions. For revision surgery, either endoprosthetic replacements or metaphyseal sleeves can be used for the repair, however, in cases of severe defects that are deemed “too severe” for reconstruction, endoprosthetic replacement of the affected area is recommended. However, endoprosthetic replacements have been associated with high complication rates (high incidence rates of prosthetic joint infection), while metaphyseal sleeves have a more acceptable complication profile and are therefore preferred. Despite this, no guidance exists as to the maximal limit of bone loss, which is acceptable for the use of metaphyseal sleeves to ensure sufficient axial and rotational stability. Therefore, this study assessed the effect of increasing bone loss on the primary stability of the metaphyseal sleeve in the proximal tibia to determine the maximal bone loss that retains axial and rotational stability comparable to a no defect control. Methods. to determine the pattern of bone loss and the average defect size that corresponds to the clinically defined defect sizes of small, medium and large defects, a series of pre-operative x-rays of patients with who underwent revision TKA were retrospectively analysed. Ten tibiae sawbones were used for the experiment. To prepare the bones, the joint surface was resected the typical resection depth required during a primary TKA (10mm). Each tibia was secured distally in a metal pot with perpendicular screws to ensure rotational and axial fixation to the testing machine. Based on X-ray findings, a fine guide wire was placed 5mm below the cut joint surface in the most medial region of the plateau. Core drills (15mm, 25mm and 35mm) corresponding to small, medium and large defects were passed over the guide wire allowing to act at the centre point, before the bone defect was created. The test was carried out on a control specimen with no defect, and subsequently on a Sawbone with a small, medium or large defect. Sleeves were inserted using the published operative technique, by trained individual using standard instruments supplied by the manufacturers. Standard axial pull-out (0 – 10mm) force and torque (0 – 30°) tests were carried out, recording the force (N) vs. displacement (mm) curves. Results. A circular defect pattern was identified across all defects, with the centre of the defect located 5mm below the medial tibial base plate, and as medial as possible. Unlike with large defects, small and medium sized defects reduced the pull-out force and torque at the bone-implant interface, however, these reductions were not statistically significant when compared to no bony defect. Conclusions. This experimental study demonstrated that up to 35mm radial defects may be an acceptable “critical limit” for bone loss below which metaphyseal sleeve use may still be appropriate. Further clinical assessment may help to confirm the findings of this experimental study. This study is the first in the literature to aim to quantify “critical bone loss” limit in the tibia for revision knee arthroplasty. Declaration of Interest. (a) fully declare any financial or other potential conflict of interest

Abstract. Objectives. 1. To investigate the effect of revision total knee replacement (TKR) on gait kinematics in patients with a primary TKR and instability.2. To compare gait kinematics between patients with a well-functioning TKR and those with a primary TKR and symptoms of instability. Methods. This single-centre observational study is following patients who have had a revision TKR due to knee instability. Data was collected pre- and post-operatively at 8–12 week follow-up. The data was compared to a control group of 18 well-functioning TKR patients. Kinematic gait data was collected during routine clinics using a treadmill-based infrared 3D system (Vicon, Oxford, UK) and a published lower limb marker-set. Patients performed 15 strides at three different speeds: 0.6mph, self-selected, and a ‘slow walk’ normalised to leg length (Froude number 0.09). PROMs questionnaires were collected. NHS ethical approval was obtained. Results. Data was collected for 18 well-functioning TKR patients and 8 revision TKR patients pre- and post-operatively, but only 5 could walk at the normalised speed. When walking at a normalised speed (Froude 0.09), patients with a TKR with instability had reduced range of knee flexion (52° (sd 14)) compared to those with a well-functioning TKR (59° (sd 11)). Short term follow-up after a revision TKR operation demonstrated a stiffer knee (45° (sd 12)). However, those with revision TKR had a more flexed knee during stance phase. Conclusions. At short-term follow-up, this cohort of revision TKR patients appear to have reduced flexion range, while remaining more flexed during stance. This may represent a less efficient gait pattern, which may also adversely affect the implant[1]. Longer term follow-up may demonstrate whether this normalises with post-operative rehabilitation. Declaration of Interest. (b) declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research reported:I declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project

Shortening of patellar tendon after total knee arthroplasty (TKA) was previously reported by several studies. Its etiology still remains controversial. Patellar tendon shortening, a direct cause of patella baja, has a dramatic negative impact in terms of clinical outcomes after TKA. Main objective of this study is to assess the feasibility of utilizing a different technique with Ultrasound that is easy to use, cost-effective and able to eliminate the problem of differential magnification occurring in other techniques which count on standard x-rays and to establish the correlation between clinical outcomes and changes in patellar tendon length and thickness after TKA. The study was designed as prospective cohort and, after a minimum of 4-year-follow up period, 47 knees of 24 patients who had undergone primary TKA without patellar resurfacing were included in the study. All patients were scored with Kujala and HSS scores and all patellar tendons were evaluated with USG regarding their length and thickness. We used conventional grey-scale ultrasound imaging (US) to determine any changes in patellar tendon morphology. All cases were evaluated by the same radiologist. The patellar tendon was examined with the knee in 30° flexion. The flexion angle helped to stretch the extensor mechanism and avoid anisotropy (concavity) of the patellar tendon. The transducer was placed along the long axis of the tendon. The patellar tendon was initially examined in the longitudinal plane in order to measure the total length. Then, total length was divided into three parts and sagittal thickness was calculated at the proximal, median, and distal thirds of the patellar tendon. Both the length and thickness of the tendon were measured before surgery and at the 4th year of follow-up. Of the 47 knees that were included in our study, the mean pre-operative and postoperative length of the patellar tendon was 40.78±6.15 mm and 35.93±4.52 mm. Our results suggested significant shortening of the patellar tendon after primary TKA surgery (p<0.05). Intergroup analysis suggested that reduced sagittal thickness in the proximal third of the tendon was more strongly correlated with an increase in functional outcomes (p<0.05). Our results suggested no significant difference in clinical outcome scores between patients with increased or decreased length of the patellar tendon after TKA (p>0.05). We suggest that determining morphologic changes in sagittal thickness as well as length is important in explaining some of the ambiguous causes of anterior knee pain and impaired clinical outcomes after TKA. More accurate documentation of morphologic changes in the patellar tendon after TKA will certainly help to develop new techniques by surgeons or avoid some existing routines that may harm the tendon. USG is a feasible method for evaluating patellar tendon morphology after TKA but more future studies are needed

Introduction and Objective. Kinesiophobia, the fear of physical movement and activity related to injury vulnerability, has been linked to sub-optimal outcomes following total knee replacement (TKR). This systematic review has two aims: to define the relationship between kinesiophobia and functional outcomes, pain and range of motion following TKR, and to evaluate published treatments for kinesiophobia following TKR. Materials and Methods. A primary search was performed in March 2020. English-language studies recruiting adult primary TKR patients, using the Tampa Scale of Kinesiophobia (TSK) were included. Study quality was assessed using the Newcastle Ottawa Scale for cohort or case control studies, and the Cochrane Collaboration Risk of Bias tool for randomised controlled trials. Results. All thirteen included papers (82 identified) showed adequately low risk of methodological bias. TSK1 (activity avoidance) correlated with WOMAC functional score at 12 months in three studies (r=0.20 p<0.05, R=0.317 p=0.001, and correlation coefficient 0.197 p=0.005). TSK score significantly correlated with mean active range of motion (ROM) at six months (105.33 (SD=12.34) vs 85.53 (SD=14.77) p=0.000) post-operation. Three post-operative interventions improved TSK score vs control following TKR: a home-based functional exercise programme (TSK −14.30 (SD=0.80) vs −2.10 (SD=0.80) p<0.001)), an outpatient CBT programme (TSK 27.76 (SD=4.56) vs 36.54 (SD=3.58), and video-based psychological treatment (TSK 24 (SD=5) vs 29 (SD=5) p<0.01). Conclusions. Kinesiophobia negatively affects functional outcomes up until one year post-operatively, while active ROM is reduced up to six months post procedure. Post-operative functional and psychological interventions can improve kinesiophobia following TKR

Outcomes for guided motion primary total knee arthroplasty (TKA) in obese patients are unknown. 1,684 consecutive patients underwent 2,059 primary TKAs with a second-generation guided motion implant between 2011–2017 at three European and seven US sites. Of 2,003 (97.3%) TKAs in 1,644 patients with BMI data: average age 64.5 years; 58.4% females; average BMI 32.5 kg/m2; 13.4% had BMI ≥ 40 kg/m2. Subjects with BMI ≥ 40 kg/m2 had longest length of hospital stay (LOS) at European sites; LOS similar at US sites. Subjects with BMI ≥ 40 kg/m2 (P=0.0349) had longest surgery duration. BMI ≥ 40 kg/m2 had more re-hospitalizations or post-TKA reoperations than BMI < 40 kg/m2 (12.7% and 9.2% at five-year post-TKA, P<0.0495). Surgery duration and long-term complication rates are higher in patients with BMI ≥ 40 kg/m2, but device revision risk is not elevated

Patients ≤ 55 years have a high primary TKA revision rate compared to patients >55 years. Guided motion knee devices are commonly used in younger patients yet outcomes remain unknown. In this sub-group analysis of a large multicenter study, 254 TKAs with a second-generation guided motion knee implant were performed between 2011–2017 in 202 patients ≤ 55 years at seven US and three European sites. Revision rates were compared with Australian Joint Registry (AOANJRR) 2017 data. Average age 49.7 (range 18–54); 56.4% females; average BMI 34 kg/m2; 67.1% obese; patellae resurfaced in 98.4%. Average follow-up 4.2 years; longest follow-up six years; 27.5% followed-up for ≥ five years. Of eight revisions: total revision (one), tibial plate replacements (three), tibial insert exchanges (four). One tibial plate revision re-revised to total revision. Revision indications were mechanical loosening (n=2), infection (n=3), peri-prosthetic fracture (n=1), and instability (n=2). The Kaplan-Meier revision estimate was 3.4% (95% C.I. 1.7% to 6.7%) at five years compared to AOANJRR rate of 6.9%. There was no differential risk by sex. The revision rate of the second-generation guided motion knee system is lower in younger patients compared to registry controls

Introduction. As the demand for primary total knee arthroplasty (TKA) has been on the rise, so will be the demand for revision knee surgery. Nevertheless, our knowledge on the modes of failure and factors associated with failure of knee revision surgery is considerably lower to that known for primary TKA. To date, this has been mostly based on case series within the literature. Therefore, the aim of this study was to evaluate the survivorship of revision TKA and determine the reasons of failure. Methods. A retrospective study was conducted with prior approval of the institutional audit department. This involved evaluation of existing clinical records and radiographs of patients who underwent revision knee surgery at our institution between 2003 and 2015. Re-revision was identified as the third or further procedure on the knee in which at least one prosthetic component was inserted or changed. Results. 95 patients were identified who had re-revision knee replacement. Of these, there were 46 men (48%) and 49 women (52%) with an average age of 65 yrs. Infection was the main cause of failure (35.8%) followed by aseptic loosening (27.4%) and extensor mechanism problems leading to reduced range of motion (7.4%). Other causes included MCL Laxity (3.2%), oversized implants (3.2%) and fracture of the cement mantle (1.1%). The mean survivorship of revision knee replacements in our cohort was 31 months (Range between 1 – 119 months). Conclusion. The survival of knee re-revision implants is considerably different from primary TKA implants. The results of our study provide an improved understanding of the modes of failure of re-revision knee replacements, enabling orthopaedic surgeons the opportunity to better understand the current problems associated with revision knee surgery and the potential to improve our outcomes by tackling these issues