Introduction. Acute kidney injury is a recognised post-operative complication in primary joint replacement. Recently it has been demonstrated that antibiotic regimen can significantly impact on the proportion of patients who develop acute kidney impairment post-operatively. Within our unit an increased rate of acute kidney injury had been noted post-operatively over the last 5 years. This increase followed the introduction of a rapid recovery protocol for arthroplasty patients. Our aim was determine whether we could identify a causative factor or those who were at increased risk of post-operative renal impairment. Methods. Data were collected for 413 patients initially retrospectively but continued prospectively. Univariable and multivariable analysis was performed to determine any causative factors. The primary increase was 150% increase in baseline creatinine, but as some authors recognise an increase in 125% this was also analysed. Results. Within the 12 month period studied 23.3% of patients developed acute kidney injury, with an increase of 125% of their baseline creatinine. 8.23% of patients developed an increase of 150% in their creatinine levels. Age, previous renal failure and the pre-operative use of an ACE inhibitor were found to be statistically higher in the renal failure group. The uni-variable analysis also demonstrated that patients who received a small volume of post-operative intravenous fluids had a lower rate of renal failure than those who received no fluids (10% vs. 23%; p = 0.04). The multivariable regression analysis demonstrated that age was the only statistically significant positive predictive factor in developing renal failure. Antibiotic regimen had no effect. Discussion. Renal impairment has significant impact on patient morbidity and post-operative management. It increases the length of stay, and may potentially require more invasive therapy. We have demonstrated that the identified risk factors are non-modifiable but that a gentamicin and teicoplanin regimen was not an implicated causative factor

The accurate positioning of the total knee arthroplasty affects the survival of the implants(1). Alignment of the femoral component in relation to the native knee is best determined using pre- and post-operative 3D-CT reconstruction(2). Currently, the scans are visualised on separate displays. There is a high inter- and intra-observer variability in measurements of implant rotation and translation(3). Correct alignment is required to allow a direct comparison of the pre- and post-operative surfaces. This is prevented by the presence of the prostheses, the bone shape alteration around the implant, associated metal artefacts, and possibly a segmentation noise. The aim is to create a novel method to automatically register pre- and post-operative femora for the direct comparison of the implant and the native bone. The concept is to use post-operative femoral shaft segments free of metal noise and of surgical alteration for alignment with the pre-operative scan. It involves three steps. Firstly, using principal component analysis, the femoral shafts are re-oriented to match the X axis. Secondly, variants of the post-operative scan are created by subtracting 1mm increments from the distal femoral end. Thirdly, an iterative closest point algorithm is applied to align the variants with the pre-operative scan. For exploratory validation, this algorithm was applied to a mesh representing the distal half of a 3D scanned femur. The mesh of a prosthesis was blended with the femur to create a post-operative model. To simulate a realistic environment, segmentation and metal artefact noise were added. For segmentation noise, each femoral vertex was translated randomly within +−1mm,+−2mm,+−3mm along its normal vector. To create metal artefact random noise was added within 50 mm of the implant points in the planes orthogonal to the shaft. The alignment error was considered as the average distance between corresponding points which are identical in pre- and post-operative femora. These preliminary results obtained within a simulated environment show that by using only the native parts of the femur, the algorithm was able to automatically register the pre- and post-operative scans even in presence of the implant. Its application will allow visualisation of the scans on the same display for the direct comparison of the perioperative scans. This method requires further validation with more realistic noise models and with patient data. Future studies will have to determine if correct alignment has any effect on inter- and intra-observer variability

We hypothesized that using the navigation system, intra-operative knee kinematics after implantation measured may predict that post-operative kinematic in activities of daily living. Our aim was to compare intra-operative knee kinematics by a computed tomography (CT)-based navigation system and post-operative by the 2- to 3-dimensional registration techniques (2D3D). This study were performed for 8 patients (10 knees, medial osteoarthritis) who underwent primary PS TKA using CT-based navigation system. The median follow-up period from operation date to fluoroscopic surveillance date was 13 months (range 5 – 37 months). Navigation and 2D3D had a common coordinate origin for components. Medial and lateral femoral condyle anterior-posterior translation (MFT and LFT) were respectively defined as the distance of the projection of the points (which was set on the top of the posterior femoral pegs) onto the axial plane of the tibial coordinate system. Intraoperative kinematics was measured using the navigation system after final implantation and closure of the retinaculum during passive full flexion and extension imposed by the surgeon. Under fluoroscopic surveillance in the sagittal plane, each patient was asked to perform sequential deep knee flexion under both weight bearing (WB) and non-weight bearing (NWB) conditions from full extension to maximum flexion. Repeated two-way ANOVA (tasks × flexion angles) were used, and then post-hoc test (paired t-tests with Boferroni correction) were performed. The level of statistical significant difference was set at 0.05 on two-way ANOVAs and 0.05 / 3 on post-hoc paired t-tests. Mean range of motion between femoral and tibial components were Intra-operative (Intra): 28.0 ± 9.7, NWB conditions: 120.6 ± 11.1, WB conditions: 125.1 ± 12.9°, respectively. Mean ER (+) / IR (−) from 0° to 120° were Intra-operative (Intra): 9.3 ± 10.2°, NWB conditions: 8.1 ± 8.9, WB conditions: 5.2 ± 7.0, respectively. Mean MFT /LFT from 0° to 90° were Intra; 4.4 ±14.8/ 4.2± 8.5mm, NWB; 6.2 ± 6.9 / 9.2 ± 3.1 mm, WB; 9.2 ± 3.5 / 7.4 ± 2.8 mm, respectively. Mean MFT /LFT from 90° to 120° were Intra; −4.4 ± 2.5 / −5.7 ± 2.9 mm, NWB; −5.5 ± 1.8 / −8.2 ± 0.6 mm, WB; −4.0 ± 1.9 / −5.4 ± 2.3mm, respectively. Mean ADD/ABD from 0° to 120° were Intra;-4.2 ± 3.0, NWB; −0.2 ± 2.1, WB; −0.1 ± 0.8, respectively. Repeated two-way ANOVA showed a significant all interaction on kinematic variables (p<0.05). No statistically significant difference at post-hoc test was found in ER/ IR of all tasks and MFT /LFT of Intra vs NWB and Intra vs WB from 0° to 120° (p>0.05 / 3). The Conditions of these tasks were different from each others. Our study demonstrated that intra-operative kinematics could predict post-operative kinematics

Summary Statement. Our data suggest that postoperative component positioning in TKA with PSPG is not consistent with pre-operative software planning. More studies are needed to rule out possible learning curve in this study. Introduction. Patient specific positioning guides (PSPGs) in TKA are based on MRI or CT data. Preoperatively, knee component positions can be visualised in 3-dimensional reconstructed images. Software allows anticipation of component position. From software planning PSPGs are manufactured and those PSPGs represent intra-operative component alignment. To our knowledge, there are no studies comparing pre-operative software planning with post-operative alignment. Aim of this study is to investigate the correlation between pre-operative planning of component positioning and the post-operative achieved alignment with PSPG technique. Patients & Methods. The first 25 TKA (cemented Vanguard® Complete Knee System, Biomet) with PSPG (Signature™ Biomet) performed at Telemark Hospital in 2009–2010 and the first 17 TKA with PSPG performed at Oslo University Hospital in 2010–2011 were included. A postoperative CT scanning and measurement protocol was used (Perth protocol). CT measurements were performed by 2 independent observers and comparative with pre-operative software (Materialise) planning. Component position angles of femur and tibia were measured. Mechanical axis for both femoral and tibial component angles in all planes was defined as zero degrees. Target angle for femoral component in sagittal plane was set to 2,8 degrees flexion on average and for the tibial tray to 3 degrees of posterior slope. Tibial rotation was in most cases obtained by using extra-medullary guide and therefore not included in this study. Results. In respectively coronal, sagittal and axial plane the femoral component angle was on average 1.2° in varus, SD 1.6 (1.7° valgus −4.5° varus), 4.4° in flexion, SD 3.9 (17.3° flexion −1.6° extension) and 0.5° in external rotation, SD 0.1 (2.3° internal rotation −4.3° external rotation). For the tibial component angle the component was on average 0,5° in varus (3.5° valgus −7.3° varus) and 3.7° posterior slope, SD 2.3 (8.8° flexion −2.4° extension). Intra-class correlation (ICC) between the 2 independent observers was for femoral component in coronal, sagittal and axial plane 0.85, 0.93 and 0.63 and tibial component in coronal and sigittal plane 0.94 and 0.95. Discussion/Conclusion. We expected that our measurements would be close to the pre-operative values. Although the mean values of post-operative measurements are close to pre-operative software planning, we found a considerable spread. Possible explanation might be error levels in pre-operative wrong identification of landmarks from MRI and/or different identification of bony landmarks on CT and intra-operative errors. All measurements were performed from the first Signatures performed in both hospitals. An early learning curve might explain some of the outliers. Time between manufacturing date and performed operation was in most cases several months, but less than the advocated 6 months. This time gap can theoretically provide a less proper fit in some cases due to slight change of anatomy in a progressive osteoarthritis. Our data suggest that postoperative positioning is not consistent with preoperative planning. This may be caused by the an early learning curve. It is uncertain whether this inconsistency is of clinical relevance. More data is necessary to prove any benefit of PSPG compared to existing procedures for TKA

We investigated the effect of mitomycin-C on the reduction of the formation of peritendinous fibrous adhesions after tendon repair. In 20 Wistar albino rats the tendo Achillis was cut and repaired using a modified Kessler technique. The rats were divided into two equal groups. In group 1, an injection of mitomycin-C was placed between the tendon and skin of the right leg. In group 2, an identical volume of sterile normal saline was injected on the left side in a similar fashion. All the rats received mitomycin-C or saline for four weeks starting from the day of operation. The animals were killed after 30 days. The formation of peritendinous fibrous tissue, the inflammatory reaction and tendon healing were evaluated. The tensile strength of the repaired tendons was measured biomechanically. Microscopic evidence of the formation of adhesions and inflammation was less in group 1. There was no significant difference in the tensile load required to rupture the repaired tendons in the two groups. Mitomycin-C may therefore provide a simple and inexpensive means of preventing of post-operative adhesions

Background

Meniscus repair can restore the function of torn meniscus in anterior cruciate ligament (ACL)-reconstructed knees. However, few reports investigate the relationship between concurrent meniscus repair with ACL reconstruction and postoperative meniscal position. This study aimed to evaluate the size of the medial meniscus in patients who underwent ACL reconstruction and concomitant all-inside medial meniscus repair.

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.

Post-operative check radiographs following Total Hip Replacements (THR) are routine practice in most orthopaedic units. In our unit an Anteroposterior and Turned Lateral View (TLV) radiograph was used routinely in this assessment, but the TLV method has anecdotally been reported as painful by patients. We undertook a study to evaluate patients' experiences of pain using this technique and to consider if a change to a Horizontal Beam Lateral View (HBLV) radiograph method would result in a reduction in pain. The study was conducted in two phases. Patients who underwent a primary THR and subsequent post-operative TLV over 3months (n=46) were contacted by telephone and asked to grade their experience using a numerical and descriptive pain scale. After a change in practice to HBLV, the study was repeated (n=53) to identify any difference in pain. Ten radiographs were randomly selected from each group and assessed for radiation exposure and quality by two independent assessors. 87.0% of patients who underwent the TLV radiograph described the post-operative radiograph as painful, with a mean pain score of 7.44+1.5. After a change in practice to the HBLV radiograph, only 28.4% of patients experienced any pain, with a significantly lower mean pain score of 1.00+1.89 (p< 0.001). There was a significant increase in radiation dose in the HBLV vs. TLV method (62.4mAs vs. 25.8mAs, p< 0.001). HBLV X-ray quality was only slightly inferior to TLV when evaluating stem alignment and cement mantle quality. There was a dramatic reduction in both number of patients experiencing pain and level of pain experienced when switching from TLV to HBLV radiographs; this is most likely due to reduced direct pressure on the wound post-operatively. X-ray quality was not compromised, and whilst there was increased radiation exposure, the benefits in patient experience were felt to outweigh this. We recommend the HBLV radiograph method when performing a lateral post-operative check x-ray following THR

Introduction. Ostochondral lesion of the knee is a common cause of chronic knee pain. Arthroscopic treatment with subcondral microfracture is a widespread technique leading to noticeable improvement of knee function and pain. To improve the effectiveness of this treatment options, we thought to add intra (PRF) or post-operative (PRP) growth factors. Platelet rich plasma (PRP) is obtained by centrifugation of the blood to produce a plasma with high concentration of platelets and growth factors. This latter represents a promising method to manage degenerative cartilage lesion and can be used postoperatively to improve clinical results of patients treated arthroscopically. Platelet Rich Fibrin (PRF) has been presented as a second-generation platelet concentrate, and it is used intraoperatively to cover the microfracuteres’ holes. No literature was found about using of PRF intraoperative in association with arthroscopic microfracture technique. The aim of this study is to compare clinical outcomes of the treatment of knee osteochondral lesion using arthroscopic microfracture technique alone or in association with PRF Intraoperative application using “Vivostat” system or with PRP “ReGen Lab” postoperative injection. Patients & Methods. 90 patients with clinical and radiographic evidence of osteochondral lesion of the medial or lateral compartment of the knee were enrolled. All patients received arthroscopic debridement and Microfractures and were randomised into 3 groups: 30 patients received microfractures and intraoperative PRF “Vivostat” injection(Group A), 30 patients received microfracture and 3 intra-articular injections of 5.5 mL PRP “Regen”(Group B), 30 patients received microfracture only. IKDC, KOOS and VAS score were administered to all patients before starting the treatment, at 1, 6 and 12 months from the end of the management. Results. Patients who received microfracture and PRF intraoperative application provided the best outcomes, showing a significant higher clinical scores (P<0.001) compared to the other two groups. Patients underwent PRP postoperative administration reported significant higher score than those undergoing arthroscopic microfracture alone (P<0.005), but lesser than Intraoperative PRF group at 6 months and 1 year follow up. Discussion/Conclusion. Treatment of osteochondral lesions of the knee using microfracture technique significantly improved functional and pain scores from the pre- to postoperatively time in the overall cohort. Intraoperative application of PRF shows significantly better outcome than postoperative PRP injections. However, additional treatment with intra-articular PRP injection as an adjunct to microfracture technique may offer better clinical outcomes over microfracture technique alone

Introduction:. Mayo 2A Olecranon fractures are traditionally managed with a tension band wire device (TBW) but locking plates may also be used to treat these injuries. Objectives:. To compare clinical outcomes and treatment cost between TBW and locking plate fixation in Mayo 2A fractures. Methods:. All olecranon fractures admitted 2008–2013 were identified (n=129). Patient notes and radiographs were studied. Outcomes were recorded with the QuickDASH (Disabilies of Arm, Shoulder and Hand) score. Incidence of infection, hardware irritation, non-union, fixation failure and re-operation rate were recorded. Results:. 89 patients had Mayo 2A fractures (69%). Of these patients 64 underwent TBW (n=48) or locking plate fixation (n=16). The mean age for both groups were 57 (15–93) and 60 (22–80) respectively. In the TBW group, the final follow-up QuickDASH was 12.9, compared with 15.0 for the Locking plate group. There was no statistically significant difference between either group (p = 0.312). 19 of the 48 TBW patients had complications (48%). There was 1 infection (2%). 15 cases of metalwork irritation (31%). 1 non-union (2%). 2 fixation failures (4%). 14 of the 48 TBW patients had re-operations (29%). There were 13 removal of metalwork procedures (27%), 1 washout (2%) and 2 revision fixations (4%). There were 0 complications and 0 re-operations in the 16 patients who underwent locking plate fixation. This was statistically significant, (p = 0.003) and (p= 0.015) respectively. TBW costs £7.00 verses £244.10 for a locking plate. Theatre costs were equivalent. A 30 minute day surgery removal of metalwork or similar case costs £1420. In this cohort, when costs of re-operation were included, locking plates were on average £177 less per patient. Conclusions:. Locking plates are superior to TBW in terms of incidence of post-operative morbidity and re-operation rate. Financial savings may be made by choosing a more expensive initial implant

Summary

Computer assisted surgery (CAS) during total knee arthroplasty (TKA) is known to improve prosthetic alignment in coronal and sagittal plane. In this systematic review, no evidence is found that CAS also improves axial component orientation when used during TKA.

Summary

Syndesmotic malreduction or failure to restore fibular length are the leading causes for early reoperation after ankle fracture surgery. Anatomic fracture reduction and congruent ankle mortise can be achieved in the majority of cases following revision surgery.

The postoperative course of median nerve decompression in the carpal tunnel syndrome may sometimes be complicated by postoperative pain, paresthesias, and other unpleasant symptoms, or be characterized by a slow recovery of nerve function due to prolonged preoperative injury causing extensive nerve damage.

The aim of this study is to explore any possible effects of alpha lipoic acid (ALA) in the postoperative period after surgical decompression of the median nerve at the wrist.

Patients were enrolled with proven carpal tunnel syndrome and randomly assigned into one of two groups: Group A: surgical decompression of the median nerve followed by ALA for 40 days. Group P: surgical decompression followed by placebo. The primary endpoint of the study was nerve conduction velocity at 3 months post surgery, Other endpoints were static 2 point discrimination, the Boston score for hand function, pillar pain and use of pain killers beyond the second postoperative day.

ALA did not show to significantly improve nerve conduction velocity or Boston score. However, a statistically significant reduction in the postoperative incidence of pillar pain was noted in Group A. In addition, static 2 point discrimination showed to be significantly improved by ALA.

Administration of ALA following decompression of the median nerve for carpal tunnel release is effective on nerve recovery, although this is not detectable through nerve conduction studies but in terms of accelerated and improved static two-point discrimination.

The use of ALA as a supplementation for nerve recovery after surgical decompression may be extended to all types of compression syndromes or conditions where a nerve is freed from a mechanical insult.

Furthermore, ALA limits post-decompression pain, including late pericicatricial pain at the base of the palm, the so called pillar pain, which seems to be associated with a reversible damage to the superfical sensitive small nerve fibers.

In conclusion postoperative administration of ALA for 40 days post-median nerve decompression was positively associated with nerve recovery, induced a lower incidence of postoperative pillar pain and was associated with a more rapid improvement of static two-point discrimination. This treatment is well tolerated and associated with high levels of satisfaction and compliance, supporting its value as a standard postoperative supplementation after carpal tunnel decompression.

Introduction: Physical activity is a major outcome in total hip arthroplasty (THA) and discharge criterion. Increasing immediate post-op activity may accelerate discharge, enable fast track surgery and improve general rehabilitation. Preliminary evidence (O'Halloran P.D. et al. 2015) shows that feedback via motivational interviewing can result in clinically meaningful improvements of physical activity. It was the aim of this study to use wearable sensor activity monitors to provide and study the effect of biofeedback on THA patients' activity levels. It was hypothesized that biofeedback would increase in-hospital and post-discharge activity versus controls.

Methods: In this pilot study, 18 patients with osteoarthritis receiving elective primary THA followed by a rapid recovery protocol with discharge on day 3 after surgery (day 0) were randomized to the feedback group (n=9, M/F: 4:5, age 63.3 ± 5.9 years, BMI 26.9 ± 5.1) or a non-feedback control group (n=9, M/F: 0:9, age 66.9 ± 5.1 years, BMI 27.1 ± 4.0). Physical activity was measured using a wearable sensor and parameters (Time-on-Feet (ToF), steps, sit-stand-transfers (SST), mean cadence (steps/min)) were calculated using a previously validated algorithms (Matlab). For the in-hospital period data was calculated twice daily (am, ca. 8–13:00h and pm, ca. 13–20:00h) of day 1 (D1) and 2 (D2). The feedback group had parameters reported back twice (morning, lunch) using bar charts comparing visually and numerically their values (without motivational instructions) to a previously measured reference group (n=40, age 71 ±7 years, M:F 16:24) of a conventional discharge protocol (day 4/5). Activity measures continued from discharge (D3) until day 5 (D5) at home.

Results: Randomization resulted in matched groups regarding age and BMI, but not gender. The first post-op activity assessment (D1am) was identical between groups. Also thereafter similar values with no significant differences in any parameter were seen, e.g. the time-on-feet at D2PM was 59.2 ±31.7min (feedback) versus 62.9 ±39.2min (controls). Also on the day of discharge and beyond, no effect from the in-hospital feedback was measured. For both groups the course of activity recovery showed a distinct drop on day 4 following a highly active day of discharge (D3). On day 5, activity levels only recovered partially. For both groups, all quantitative activity parameters were significantly higher than the reference values used for feedback. Only cadence as a qualitative measure was the same like reference values.

Discussion: Biofeedback using activity values from a body-worn monitor did not increase in-hospital or immediate post-op home activity levels compared to a control group when using the investigated feedback protocol. In general, while the day of discharge steeply boosts patient activity, the day after at home results in an activity drop to near in-patient levels before discharge. In a fast track surgery protocol, it may be of value to avoid this drop via patient education or home physiotherapy. Biofeedback using activity monitors to increase immediate post-op activity for fast track surgery or improved recovery may only be effective when feedback goals are set higher, are personalised or have additional motivational context.

Summary Statement

Objectifying postoperative recovery of patients with comminuted tibial plateau fractures treated with a unilateral plate trough the use of a gait analysis system.

Painful OA is linked to CNS changes in pain processing. Temporal summation of pain (TSP) is a measure of one such CNS change, central sensitization. TSP is defined using a series (≥0.33Hz) of painful stimuli and is a predictor of postoperative pain, experienced by 20% of patients after total knee replacement (TKR) surgery. This study has developed a protocol to use functional MRI to assess CNS changes in OA pain processing.

This pilot includes 3 participants with chronic knee OA pain awaiting TKR (62 ± 4.4) and 5 healthy volunteers (50 ± 13.6). 3-Tesla BOLD fMRI brain scans were recorded during short series of one second painful stimuli, applied using an automated inflatable cuff to the calf muscle of the leg with the affected knee or left side in healthy volunteers. The pain intensity at onset and during the 10 painful stimuli were recorded using a numerical rating scale. The pattern of brain activation was averaged across noxious stimuli, and the differential activation compared the 1st vs. 10th (last) stimulus. Bone marrow lesions (BMLs), synovitis and effusion size were scored from 3-Tesla knee MRI's using MOAKS scoring.

TSP was raised in OA patients compared to control group (p=0.023). TSP brain activity in the chronic OA patients displayed higher signal within the subgenual anterior cingulate (sgACC) compared to healthy volunteers. Knee MRI identified OA patient's exhibited higher BML scores (p=0.038) and more knee effusion (p=0.018), but the lack of synovitis did not differ from control group (p=0.107).

Enhanced TSP in chronic knee OA pain may be linked with augmented responses in emotional circuitry. BMLs and effusion size appear to contribute more with pain than synovitis. These results may help understand sensitization to improve outcomes for patients with knee OA undergoing TKR surgery.

Introduction. Accurate assessment of alignment in pre-operative and post-operative knee radiographs is important for planning and evaluating knee replacement surgery. Existing methods predominantly rely on manual measurements using long-leg radiographs, which are time-consuming to perform and are prone to reliability errors. In this study, we propose a machine-learning-based approach to automatically measure anatomical varus/valgus alignment in pre-operative and post-operative standard AP knee radiographs. Method. We collected a training dataset of 816 pre-operative and 457 one-year post-operative AP knee radiographs of patients who underwent knee replacement surgery. Further, we have collected a separate distinct test dataset with both pre-operative and one-year post-operative radiographs for 376 patients. We manually outlined the distal femur and the proximal tibia/fibula with points to capture the knee joint (including implants in the post-operative images). This included point positions used to permit calculation of the anatomical tibiofemoral angle. We defined varus/valgus as negative/positive deviations from zero. Ground truth measurements were obtained from the manually placed points. We used the training dataset to develop a machine-learning-based automatic system to locate the point positions and derive the automatic measurements. Agreement between the automatic and manual measurements for the test dataset was assessed by intra-class correlation coefficient (ICC), mean absolute difference (MAD) and Bland-Altman analysis. Result. Analysing the agreement between the manual and automated measurements, ICC values were excellent pre-/post-operatively (0.96, CI: 0.94-0.96) / (0.95, CI: 0.95-0.96). Pre-/post-operative MAD values were 1.3°±1.4°SD / 0.7°±0.6°SD. The Bland-Altman analysis showed a pre-/post-operative mean difference (bias) of 0.3°±1.9°SD/-0.02°±0.9°SD, with pre-/post-operative 95% limits of agreement of ±3.7°/±1.8°, respectively. Conclusion. The developed machine-learning-based system demonstrates high accuracy and reliability in automatically measuring anatomical varus/valgus alignment in pre-operative and post-operative knee radiographs. It provides a promising approach for automating the measurement of anatomical alignment without the need for long-leg radiographs. Acknowledgements. This research was funded by the Wellcome Trust [223267/Z/21/Z]

Introduction. Knee arthroplasty (KA), encompassing Total Knee Replacement (TKR) and Unicompartmental Knee Replacement (UKR), is one of the most common orthopedic procedures, aimed at alleviating severe knee arthritis. Postoperative KA management, especially radiographic imaging, remains a substantial financial burden and lacks standardised protocols for its clinical utility during follow-up. Method. In this retrospective multicentre cohort study, data were analysed from January 2014 to March 2020 for adult patients undergoing primary KA at Imperial NHS Trust. Patients were followed over a five-year period. Four machine learning models were developed to evaluate if post-operative X-ray frequency can predict revision surgery. The best-performing model was used to assess the risk of revision surgery associated with different number of X-rays. Result. The study assessed 289 knees with a 2.4% revision rate. The revision group had more X-rays on average than the primary group. The best performing model was Logistic Regression (LR), which indicated that each additional X-ray raised the revision risk by 52% (p<0.001). Notably, having four or more X-rays was linked to a three-fold increase in risk of revision (OR=3.02; p<0.001). Our results align with the literature that immediate post-operative X-rays have limited utility, making the 2nd post-operative X-ray of highest importance in understanding the patient's trajectory. These insights can enhance management by improving risk stratification for patients at higher revision surgery risk. Despite LR being the best-performing model, it is limited by the dataset's significant class imbalance. Conclusion. X-ray frequency can independently predict revision surgery. This study provides insights that can guide surgeons in evidence-based post-operative decision-making. To use those findings and influence post-operative management, future studies should build on this predictive model by incorporating a more robust dataset, surgical indications, and X-ray findings. This will allow early identification of high-risk patients, allowing for personalised post-operative recommendations

This study examined pre-operative measures to predict post-operative biomechanical outcomes in total knee arthroplasty (TKA) patients. Twenty-eight patients (female=12/male=16, age=63.6±6.9, BMI=29.9±7.4 kg/m2) with knee osteoarthritis scheduled to undergo TKA were included. All surgeries were performed by the same surgeon (GD) with a subvastus approach. Patients visited the gait lab within one-month prior to surgery and 12 months following surgery. At the gait lab, patients completed the knee injury and osteoarthritis outcome score (KOOS), a timed up and go (TUG), maximum knee flexion and extension strength evaluation, and a walking task. Variables of interest included the five KOOS sub-scores, TUG time, maximum knee flexion and extension strength normalized to body weight, walking speed, and peak knee biomechanics variables (flexion angle, abduction moment, power absorption). A Pearson's correlation was used to identify significantly correlated variables which were then inputted into a multiple regression. No assumption violations for the multiple regression existed for any variables. Pre-operative knee flexion and extension strength, TUG time, and age were used in the multiple regression. The multiple regression model statistically significantly predicted peak knee abduction moment, post-operative walking speed, and post-operative knee flexion strength. All four variables added statistically significantly to the prediction p<.05. Pre-operative KOOS values did not correlate with any biomechanical indicators of post-operative success. Age, pre-operative knee flexion and extension strength, and TUG times predicted peak knee abduction moment, which is associated with medial knee joint loading. These findings stress the importance of pre-surgery condition, as stronger individuals achieved better post-operative biomechanical outcomes. Additionally, younger patients had better outcomes, suggesting that surgeons should not delay surgery in younger patients. This delay in surgery may prevent patients from achieving optimal outcomes. Future studies should utilize a hierarchical multiple regression to identify which variables are most predictive

Prompt mobilisation after the Fracture neck of femur surgery is one of the important key performance index (‘KPI caterpillar charts’ 2021) affecting the overall functional outcome and mortality. Better control of peri-operative blood pressure and minimal alteration of renal profile as a result of surgery and anaesthesia may have an implication on early post-operative mobilisation. Aim was to evaluate perioperative blood pressure measurements (duration of fall of systolic BP below the critical level of 90mmHg) and effect on the post-operative renal profile with the newer short acting spinal anaesthetic agent (prilocaine and chlorprocaine) used alongside the commonly used regional nerve block. 20 patients were randomly selected who were given the newer short acting spinal anaesthetic agent along with a regional nerve block between May 2019 and February 2020. Anaesthetic charts were reviewed from all patients for data collection. The assessment criteria for perioperative hypotension: Duration of systolic blood pressure less than 90 mm of Hg and change of pre and post operative renal functions. Only one patient had a significant drop in systolic BP less than 90mmHg (25 minutes). 3 other patients had a momentary fall of systolic BP of less than 5 minutes. None of the above patients had mortality and had negligible change in pre and post op renal function. Only one patient in this cohort had elevation of post-operative creatinine levels but did not have any mortality. Only 1 patient died on day 3 post operatively who had multiple comorbidities and was under evaluation for GI cancer. Even in this patient the peri-operative blood pressure was well maintained (never below 90mmHg systolic) and post-operative renal function was also shown to have improved (309 pre-operatively to 150 post-operatively) in this patient. The use of short-acting spinal anaesthesia has shown to be associated with a better control of blood pressure and end organ perfusion, less adverse effects on renal function leading to early mobilisation and a more favourable patient outcome with reduced mortality, earlier mobilisation, shorter hospital stay and earlier discharge in this elderly patient cohort