Introduction. Tendon ruptures are a common injury and often require surgical intervention to heal. A refixation is commonly performed with high-strength suture material. However, slipping of the thread is unavoidable even at 7 knots potentially leading to reduced compression of the sutured tendon at its footprint. This study aimed to evaluate the biomechanical properties and effectiveness of a novel dynamic high-strength suture, featuring self-tightening properties. Method. Distal biceps tendon rupture tenotomies and subsequent repairs were performed in sixteen paired human forearms using either conventional or the novel dynamic high-strength sutures in a paired design. Each tendon repair utilized an intramedullary biceps button for radial fixation. Biomechanical testing aimed to simulate an aggressive postoperative rehabilitation protocol stressing the repaired constructs. For that purpose, each specimen underwent in nine sequential days a daily mobilization over 300 cycles under 0-50 N loading, followed by a final destructive test. Result. After the ninth day of cyclic loading, specimens treated with the dynamic suture exhibited significantly less tendon elongation at both proximal and distal measurement sites (-0.569±2.734 mm and 0.681±1.871 mm) compared to the conventional suture group (4.506±2.169 mm and 3.575±1.716 mm), p=0.003/p<0.002. Gap formation at the bone-tendon interface was significantly lower following suturing using dynamic suture (2.0±1.6 mm) compared to conventional suture (4.5±2.2 mm), p=0.04. The maximum load at failure was similar in both treatment groups (dynamic suture: 374± 159 N; conventional suture: 379± 154 N), p=0.925. The predominant failure mechanism was breakout of the button from the bone (dynamic suture: 5/8; conventional suture: 6/8), followed by suture rupturing, suture unraveling and tendon cut-through. Conclusion. From a biomechanical perspective, the novel dynamic high-strength suture demonstrated higher resistance against gap formation at the bone tendon interface compared to the conventional suture, which may contribute to better postoperative tendon integrity and potentially quicker functional recovery in the clinical setting

Abstract. Objective. Short-stem total hip arthroplasty (THA) aims to preserve the proximal bone stock for future revisions, so that the first revision should resemble a primary intervention rather than a revision. This study aimed to compare the clinical and radiological outcomes in revision THA after failed short stem versus after failed conventional stem THA. Methods. This study included forty-five patients with revision THA divided into three groups (15 each); group A: revision after short stem, group B: revision after conventional cementless stem and group C revision after conventional cemented stem. The studied groups were compared regarding 31 variables including demographic data, details of the primary and revision procedures, postoperative radiological subsidence, hospital stay, time for full weight bearing (FWB), preoperative and postoperative clinical scores. Results. Early stem subsidence (40%) was the main indication of revision in group A compared to peri-prosthetic femoral fractures (PFFs) (73.3%) and aseptic loosening (53.3%) in group B and C respectively (P=0.021). The mean time to revision was significantly shorter in group A (15 months) compared to 95.33 and 189.40 months in group B and C respectively. (P=0.005). Sixty % (9 patients) in group A were revised in the first year. The mean operative time, blood loss, postoperative blood transfusion and hospital stay were significantly lower in group A compared to group B and C (P<0.001, <0.001, 0.002 and 0.001 respectively). Revisions in group A were performed using either short stems (13.3%) or conventional stems (86.7%) whilst 80% of patients needed long stems and 20% of patients needed conventional stems in group B and C (P<0.001). The mean postoperative Harris Hip Score (HHS) at the latest follow up was 87.07, 87.53 and 85.47 in group A, B and C respectively. All PFFS had excellent results according to Beal's and Tower's criteria; all fractures healed and the implants were stable. Conclusion. The most common cause of failure of short stems is early stem subsidence. Short stem THA has specific indications and patient selection is very crucial. Preoperative templating for short stems and a detailed analysis of the individual patient anatomy in anteroposterior and lateral views are mandatory to predict the correct implant size more accurately. The use of intraoperative imaging can verify the sizing, implant position, and sufficient contact with the lateral cortex. Revision of short stem THA resembled the primary THA. If a standard implant can be used in a surgical revision instead of a longer revision stem, this can be considered as an advantage for the hip arthroplasty treatment concept. However, this only applies if the longevity of the first treatment with a short stem is comparable with that of a standard stem. 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

Abstract. Introduction. Component mal-positioning in total hip replacement (THR) and total knee replacement (TKR) can increase the risk of revision for various reasons. Compared to conventional surgery, relatively improved accuracy of implant positioning can be achieved using computer assisted technologies including navigation, patient-specific jigs, and robotic systems. However, it is not known whether application of these technologies has improved prosthesis survival in the real-world. This study aimed to compare risk of revision for all-causes following primary THR and TKR, and revision for dislocation following primary THR performed using computer assisted technologies compared to conventional technique. Methods. We performed an observational study using National Joint Registry data. All adult patients undergoing primary THR and TKR for osteoarthritis between 01/04/2003 to 31/12/2020 were eligible. Patients who received metal-on-metal bearing THR were excluded. We generated propensity score weights, using Sturmer weight trimming, based on: age, gender, ASA grade, side, operation funding, year of surgery, approach, and fixation. Specific additional variables included position and bearing for THR and patellar resurfacing for TKR. For THR, effective sample sizes and duration of follow up for conventional versus computer-guided and robotic-assisted analyses were 9,379 and 10,600 procedures, and approximately 18 and 4 years, respectively. For TKR, effective sample sizes and durations of follow up for conventional versus computer-guided, patient-specific jigs, and robotic-assisted groups were 92,579 procedures over 18 years, 11,665 procedures over 8 years, and 644 procedures over 3 years, respectively. Outcomes were assessed using Kaplan-Meier analysis and expressed using hazard ratios (HR) and 95% confidence intervals (CI). Results. For THR, analysis comparing computer-guided versus conventional technique demonstrated HR of 0.771 (95%CI 0.573–1.036) p=0.085, and 0.594 (95%CI 0.297–1.190) p=0.142, for revision for all-causes and dislocation, respectively. When comparing robotic-assisted versus conventional technique, HR for revision for all-causes was 0.480 (95%CI 0.067 –3.452) p=0.466. For TKR, compared to conventional surgery, HR for all-cause revision for procedures performed using computer guidance and patient-specific jigs were 0.967 (95% CI 0.888–1.052) p=0.430, and 0.937 (95% CI 0.708–1.241) p=0.65, respectively. HR for analysis comparing robotic-assisted versus conventional technique was 2.0940 (0.2423, 18.0995) p = 0.50. Conclusions. This is the largest study investigating this topic utilising propensity score analysis methods. We did not find a statistically significant difference in revision for all-causes and dislocation although these analyses are underpowered to detect smaller differences in effect size between groups. Additional comparison for revision for dislocation between robotic-assisted versus conventionally performed THR was not performed as this is a subset of revision for all-causes and wide confidence intervals were already observed for that analysis. It is also important to mention this NJR analysis study is of an observational study design which has inherent limitations. Nonetheless, this is the most feasible study design to answer this research question requiring use of a large data set due to revision being a rare outcome. 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

Introduction and Objective. In recent studies, robotic-assisted surgical techniques for unicompartmental knee arthroplasty (UKA) have demonstrated superior implant positioning and limb alignment compared to a conventional technique. However, the impact of the robotic-assisted technique on clinical and functional outcomes is less clear. The aim of this study was to compare the gait parameters of UKA performed with conventional and image-free robotic-assisted techniques. Materials and Methods. This prospective, single center study included 66 medial UKA, randomized to a robotic-assisted (n=33) or conventional technique (n=33). Gait analysis was performed on a treadmill at 6 months to identify changes in gait characteristics (walking speed, each degree-of-freedom: flexion–extension, abduction–adduction, internal-external rotation and anterior-posterior displacement). Clinical results were assessed at 6 months using the IKS score and the Forgotten Joint Score. Implants position was assessed on post-operative radiographs. Results. Post-operatively, the whole gait cycle was not significantly different between groups. In both groups there was a significant improvement in varus deformity between the pre- and post-operative gait cycle. There was no significant difference between the two groups in clinical scores, implant position, revision and complication rates. Conclusions. No difference of gait parameters could be identified between medial UKA performed with image-free robotic-assisted technique or with conventional technique

Introduction and Objective. The aim of this study was to evaluate whether CT-based pre-operative planning, integrated with intra-operative navigation could improve glenoid baseplate fixation and positioning by increasing screw length, reducing number of screws required to obtain fixation and increasing the use of augmented baseplate to gain the desired positioning. Reverse total shoulder arthroplasty (RSA) successfully restores shoulder function in different conditions. Glenoid baseplate fixation and positioning seem to be the most important factors influencing RSA survival. When scapular anatomy is distorted (primitive or secondary), optimal baseplate positioning and secure screw purchase can be challenging. Materials and Methods. Twenty patients who underwent navigated RSA (oct 2018 and feb 2019) were compared retrospectively with twenty patients operated on with a conventional technique. All the procedures were performed by the same surgeon, using the same implant in cases of eccentric osteoarthritis or complete cuff tear. Exclusion criteria were: other diagnosis as proximal humeral fractures, post-traumatic OA previously treated operatively with hardware retention, revision shoulder arthroplasty. Results. The NAV procedure required mean 11 (range 7–16) minutes more to performed than the conventional procedure. Mean screw length was significantly longer in the navigation group (35.5+4.4 mm vs 29.9+3.6 mm; p . .001). Significant higher rate of optimal fixation using 2 screws only (17 vs 3 cases, p . .019) and higher rate of augmented baseplate usage (13 vs 4 cases, p . .009) was also present in the navigation group. Signficant difference there is all in function outcomes, DASH score is 15.7 vs 29.4 and constant scale 78.1 vs 69.8. Conclusions. The glenoid component positioning in RSA is crucial to prevent failure, loosening and biomechanical mismatch, coverage by the baseplate of the glenoid surface, version, inclination and offset are all essential for implant survival. This study showed how useful 3D CT-based planning helps in identifying the best position of the metaglena and the usefulness of receiving directly in the operation theater real-time feedback on the change in position. This study shows promising results, suggesting that improved baseplate and screw positioning and fixation is possible when computer-assisted implantation is used in RSA comparing to a conventional procedure

Introduction. The incidence of distal femoral fractures in the geriatric population is growing and represents the second most common insufficiency fracture of the femur following fractures around the hip joint. Fixation of fractures in patients with poor bone stock and early mobilisation in feeble and polymorbide patients is challenging. Development of a fixation approach for augmentation of conventional LISS (less invasive stabilization system) plating may result in superior long-term clinical outcomes and enhance safe weight bearing. Objectives. The aim of this study was to investigate the biomechanical competence of two different techniques of augmented LISS plating for treatment of osteoporotic fractures of the distal femur in comparison to conventional LISS plating. Materials & methods. Unstable distal femoral fracture AO/OTA 33-A3 was set in artificial femora with low density simulating osteoporotic bone. Three study groups, consisting of 10 specimens each, were created for instrumentation with a 9-hole LISS plate, a LISS plate with an additional 3D-printed polyactide cylindrical intramedullary graft, as well as a LISS plate plus a medial 3.5mm LCP (locking compression plate) - double plating. All specimens were non-destructively tested under axial (20–150N) and torsional (0–4Nm) quasi-static loading. Each construct was tested with two different working length (WL) configurations (long and short) of the LISS plate. Relative movements between the most medial superior and inferior osteotomy aspects were investigated via three-dimensional motion tracking analysis. Results. Interfragmentary displacement along the femur axis (mm) under 150N axial loading was 2.03±0.23/1.65±0.27 for LISS with long/short WL, 0.18±0.06/0.18±0.04 for double plating with long/short WL, and 0.40±0.05/0.30±0.05 for LISS plus graft with long/short WL. Shear interfragmentary displacement (mm) under 4Nm torsional loading in internal rotation was 1.16±0.17/0.92±0.11 for LISS with long/short WL, 0.40±0.10/0.43±0.07 for double plating with long/short WL, and 1.09±0.13/0.82±0.11 for LISS plus graft with long/short WL. Double plating revealed significantly smaller longitudinal and shear displacement compared to the other two techniques for long and short WL, respectively (P≤0.010). In addition, LISS plus graft fixation was with significantly less longitudinal displacement in comparison to conventional LISS plating for long and short WL, respectively (P≤0.001). Long WL resulted in significantly higher longitudinal and shear displacement compared to short WL for LISS and LISS plus graft (P≤0.032), but not for double plating (P=1.000). Conclusion. Intramedullary grafting resulted in significantly increased fracture stability under axial loading in comparison to conventional LISS plating. However, it was not efficient enough to achieve comparable stability to double plating

Objectives. This study reports on a secondary exploratory analysis of the early clinical outcomes of a randomised clinical trial comparing robotic arm-assisted unicompartmental knee arthroplasty (UKA) for medial compartment osteoarthritis of the knee with manual UKA performed using traditional surgical jigs. This follows reporting of the primary outcomes of implant accuracy and gait analysis that showed significant advantages in the robotic arm-assisted group. Methods. A total of 139 patients were recruited from a single centre. Patients were randomised to receive either a manual UKA implanted with the aid of traditional surgical jigs, or a UKA implanted with the aid of a tactile guided robotic arm-assisted system. Outcome measures included the American Knee Society Score (AKSS), Oxford Knee Score (OKS), Forgotten Joint Score, Hospital Anxiety Depression Scale, University of California at Los Angeles (UCLA) activity scale, Short Form-12, Pain Catastrophising Scale, somatic disease (Primary Care Evaluation of Mental Disorders Score), Pain visual analogue scale, analgesic use, patient satisfaction, complications relating to surgery, 90-day pain diaries and the requirement for revision surgery. Results. From the first post-operative day through to week 8 post-operatively, the median pain scores for the robotic arm-assisted group were 55.4% lower than those observed in the manual surgery group (p = 0.040). At three months post-operatively, the robotic arm-assisted group had better AKSS (robotic median 164, interquartile range (IQR) 131 to 178, manual median 143, IQR 132 to 166), although no difference was noted with the OKS. At one year post-operatively, the observed differences with the AKSS had narrowed from a median of 21 points to a median of seven points (p = 0.106) (robotic median 171, IQR 153 to 179; manual median 164, IQR 144 to 182). No difference was observed with the OKS, and almost half of each group reached the ceiling limit of the score (OKS > 43). A greater proportion of patients receiving robotic arm-assisted surgery improved their UCLA activity score. Binary logistic regression modelling for dichotomised outcome scores predicted the key factors associated with achieving excellent outcome on the AKSS: a pre-operative activity level > 5 on the UCLA activity score and use of robotic-arm surgery. For the same regression modelling, factors associated with a poor outcome were manual surgery and pre-operative depression. Conclusion. Robotic arm-assisted surgery results in improved early pain scores and early function scores in some patient-reported outcomes measures, but no difference was observed at one year post-operatively. Although improved results favoured the robotic arm-assisted group in active patients (i.e. UCLA ⩾ 5), these do not withstand adjustment for multiple comparisons. Cite this article: M. J. G. Blyth, I. Anthony, P. Rowe, M. S. Banger, A. MacLean, B. Jones. Robotic arm-assisted versus conventional unicompartmental knee arthroplasty: Exploratory secondary analysis of a randomised controlled trial. Bone Joint Res 2017;6:631–639. DOI: 10.1302/2046-3758.611.BJR-2017-0060.R1

We have investigated the errors in the identification of the transepicondylar axis and the anteroposterior axis between a minimally-invasive and a conventional approach in four fresh-frozen cadaver knees. The errors in aligning the femoral prosthesis were compared with the reference transepicondylar axis as established by CT. The error in the identification of the transepicondylar axis was significantly higher in the minimal approach (4.5° of internal rotation, . sd. 4) than in the conventional approach (3° of internal rotation, . sd. 4; p < 0.001). The errors in identifying the anteroposterior axis in the two approaches were 0° (. sd. 5) and 1.8° (. sd. 5) of internal rotation, respectively (p < 0.001)

Introduction. There is much current debate concerning wear and corrosion at the taper junctions of large head total hip replacements, particularly metal-on-metal hips. Is such damage a modern concern or has it always occurred in total hip replacement but not previously noted. To investigate this five explanted V40 Exeter femoral stems (Stryker Howmedica) were obtained following revision surgery at a single centre. In all cases, the 24–26 mm femoral heads were still attached. Hypothesis. In conventional ‘small head’ modular hip prostheses such as the Exeter, negligible wear and corrosion is seen at the taper junction of explanted devices. Methods. The articulating surface and the taper junction of each femoral heads was measured using a Mitutoyo LEGEX322 co-ordinate measuring machine (CMM) In each case a wear map was generated and the wear volume from the contact surface was calculated using a bespoke MATLAB program. The accuracy of such measurements has been previously shown to be within 0.5mm3. Results. Wear analysis of the articulating surfaces found unworn surfaces with each femoral head having less than 1 mm. 3. volumetric wear. All tapers had minimal wear with volumetric wear of less than 0.5 mm. 3. . Discussion and Conclusion. The wear volumes measured fall within the CMM measuring accuracy of 0.5mm. 3. Furthermore all tapers showed low wear volumes indicating that the taper junction had functioned correctly and distributed the load across the length of the truneon. Significance. This work adds to the growing evidence that taper problems in modern hip prostheses are associated with increasing head diameter and smaller taper dimensions

Summary. Alignment results did not differ between PSG and conventional instrumentation. A small reduction in operation time and blood loss was found with the PSG system, but is unlikely of clinical significance. Length of hospital stay was identical for both groups. Introduction. Several techniques for aligning a TKA exist nowadays. Patient-specific guiding (PSG) has relatively recently been introduced to try to resolve the shortcomings of existing techniques while optimising the operative procedure. Still few reports have been published on the clinical outcome and on the peroperative results of this new technique. This prospective, double-blind, randomised controlled trial was designed to address the following research questions: 1. Is there a significant difference in outliers in alignment in the frontal and sagittal plane between PSG TKA and conventional TKA. 2. Is there a significant difference in operation time, blood loss and length of hospital stay between the 2 techniques. Patients & Methods. 180 patients were randomised for PSG TKA (group 1) or conventional TKA (group 2) in 2 centres. Patients were stratified per hospital. Alignment of the mechanical axis of the leg and flexion/extension and varus/valgus of the individual prosthesis components were measured on digital, standing, long-leg and standard lateral radiographs by 2 independent outcome assessors in both centres. Percentages of outliers, > 3°, were determined. We compared blood loss, operation time and length of hospital stay. Results. There was no statistically significant difference in mean mechanical axis or outliers in mechanical axis between groups. No statistically significant difference was found for the alignment of the individual components in the frontal plane, nor for the percentages of outliers. There was a statistically significant difference in outliers for the femoral component in the sagittal plane, with a higher percentage of outliers in the group 1 (p = 0.017). No such significant result was found for the tibial component in that plane. All interclass correlation coefficients were good. Blood loss was 100 mL less in group 1 (p = 0.000). Operation time was 5 minutes shorter in group 1 (p = 0.000). Length of hospital stay was almost identical with a mean of 3.6 days (p = 0.657). Discussion/Conclusions. The results in terms of obtaining a neutral mechanical axis and a correct position of the prosthesis components did not differ between groups. A small reduction in operation time and blood loss was found with the PSG system, but is unlikely of any clinical significance. Future research should especially focus on cost-effectiveness analysis and functional outcome of PSG TKA

Background. Accurate implant orientation is associated with improved outcomes after artificial joint replacement. We investigated if a novel augmented-reality (AR) platform (with live feedback) could train novice surgeons to orientate an acetabular implant as effectively as conventional training (CT). Methods. Twenty-four novice surgeons (pre-registration level medical students) voluntarily participated in this trial. Baseline demographics, data on exposure to hip arthroplasty, and baseline performance in orientating an acetabular implant to six patient-specific values on a phantom pelvis, were collected prior to training. Participants were randomised to a training session either using a novel AR headset platform or receiving one-on-one tuition from a hip surgeon (CT). After training, they were asked to perform the six orientation tasks again. The solid-angle error in degrees between the planned and achieved orientations was measured using a head-mounted navigation system. Results. Novice surgeons in both groups performed with a similar degree of error prior to training (AR: 14.2°±7.0°, CT: 15.7°±6.9° (p>0.05)). After training, average error was 10.7°±5.8° for AR participant and 7.2°±4.4° for CT participants. The average improvement per student was 3.5°±7.2° and 8.5°±8.0° respectively (p>0.05). Conclusions. A novel AR platform delivered training for acquiring skills to orientate an acetabular cup implant. After one session, novices trained by a hip surgeon outperformed those trained using AR. In both groups, accuracy remained below “expert” level proficiency (<5 degrees error). Further investigation is required to evaluate if novices retain skills, continue to improve with further training, and can transfer this to clinical practice

Summary Statement. In this study, we employed a novel imaging modalities, the synchrotron radiation microcomputed tomography (SRμCT) to visualise the 3D morphology of the spinal cord microvasculature and successfully obtained the 3D images. Introduction. Understanding the morphology of the spinal cord microvasculature in three-dimensions (3D) is limited by the lack of an effective high-resolution imaging technique. In this study, we used two novel imaging modalities, conventional x-ray microcomputed tomography (CμCT) and synchrotron radiation microcomputed tomography (SRμCT), to visualise the 3D morphology of the spinal cord microvasculature and to compare their utility in basic science research. Methods. (1) Sample Preparation: Ten adult Sprague-Dawley male rats (250–300 g) were randomly divided into A and B groups (n = 5). Both groups were subjected to angiography with contrast agent (Microfil MV-122, Flow Tech, CA, USA). The samples in group A were examined by CμCT, and the group B samples were analyzed through SRμCT scanning. After scanning, the samples was photographed with a stereomicroscope. (2) Images Analysis: The morphometric parameters in 2D were calculated using the Image-Pro Plus program (Ver. 6.0, Media Cybernetics. Bethesda, MD, USA), In the 3D dataset, the algorithms for the analysis of vessel structures in the VG Studio Max software package (Volume Graphics GmbH, Germany) were applied to calculate the morphological parameters of the spinal cord microvasculature. Results. The reconstructed tomographic slices of the rat spinal cord microvasculature obtained by these two techniques are illustrated. In the 2D tomographic view, the area with a high gray value, which indicates the location of the vessels, could be easily differentiated from the neural parenchymal background. The CμCT slices dataset only provided indistinctive images with weak apparent artefacts. In contrast, extensive distributions of the microvessels were found in the intrinsic neural parenchyma in the SRμCT slices. (2) The 3D reconstructed image obtained through SRμCT, provided a clear and precise configuration of the complex spatial structure and connectivity of the intensive microvasculature of the spinal cord when compared with CμCT. (3) The extracted 3D spatial distribution image of the spinal cord microvasculature was able to match the specimen's morphology photographed with a stereomicroscope. Discussion & Conclusion. In this study, we have combined two emerging techniques to capture the 3D morphological features of the rat spinal cord microvasculature in vitro for the first time. With the help of contrast agents and the advanced computed tomography algorithm, both CμCT and SRμCT were able to provide a valuable 3D volumetric dataset of the spinal cord vascular structure. These datasets could be extracted and analyzed from different angles and at multiple levels, which are analysis that were not previously possible with the conventional histological methods. However, when compared with CμCT, SRμCT was able to achieve higher-resolution vascular imaging and to obtain detailed 3D morphological features of the spinal cord microvasculature. These data imply that SRμCT may be regarded as a unique imaging technique that is more suitable than CμCT for 3D angioarchitectural investigation in preclinical neurovascular research

Background. The R3 cementless acetabular system (Smith & Nephew, Memphis, Tennessee, United States) is a modular titanium shell with an asymmetric porous titanium powder coating. It supports cross-linked polyethylene, metal and ceramic liners with several options for the femoral head component. The R3 cup was first marketed in Australia and Europe in 2007. Two recent papers have shown high failure rates of the MoM R3 system with up to 24% (Dramis et al 2014, Hothi et al 2015). There are currently no medium term clinical papers on the R3 acetabular cup. Objectives. The aim of the study is to review our results of the R3 acetabular cup with a minimum of 5 year follow up. Study Design & Methods. Patients who were implanted with the R3 acetabular cup were identified from our centre”s arthroplasty database. Our centre started implanting the R3 acetabular cup in August 2009. For this study, we only included patients with a minimum of 5 year follow up (until June 2011). Over this time period, 293 consecutive THAs were performed in 286 patients, of which 7 were bilateral staged total hip arthroplasties. The primary outcome was revision. The secondary outcomes were the Oxford hip scores and radiographic evaluation. Results. The mean age of the patients was 69.4 years (range 20–100 years). There were 117 males and 169 females in our series. The majority of the total hip arthroplasties in our series were cementless (n=283, 97%) and the rest were hybrid (n=10, 3%). The articulation bearings were as follows: ceramic on ceramic (n=167; 57%), Ceramic on Poly XLPE (n=97; 33%), Oxinium-Poly XLPE (n=19; 6.5%), stainless steel- Poly XLXE (n=10; 3.5%). The mean pre-operative Oxford Hip Score was 23 (range 10–34) and the mean Oxford Hip Score was 40 (range 33–48) at the final follow-up. Radiological evaluation showed an excellent ARA-score in all patients at five years. None of the R3 cups showed osteolysis at final follow up. There were 3 revisions in our series, of which two R3 cup were revised. The risk of revision was 0.28% at 5 years. Using Weibull analysis, it gives a 10-year estimate of 98.8% survival for the R3 cup (95%CI 95.0 to 99.6). Conclusions. Our experience at a district general hospital using the R3 acetabular system with conventional bearings showed high survivorship and is consistent with the allocated Orthopaedic Data Evaluation Panel (ODEP) rating of 5A* as rated in 2015 in the United Kingdom

Abstract

Introduction

A long nail is often recommended for treatment of complex trochanteric fractures but requires longer surgical and fluoroscopy times. A possible solution could be a nail with an appropriate length which can be locked in a minimally invasive manner by the main aiming device. We aimed to determine if such a nail model* offers similar structural stability on biomechanical testing on artificial bone as a standard long nail when used to treat complex trochanteric fractures.

Summary Statement. In young, active patients cementless THR demonstrates excellent prosthetic stability by RSA and outstanding clinical outcomes at 5 years using a tapered titanium femoral stem, crosslinked polyethylene liners and either titanium or tantalum shells. Introduction. Early femoral implant stability is essential to long-term success in total hip replacement. Radiostereometric analysis (RSA) provides precise measurements of micromotion of the stem relative to the femur that are otherwise not detectable by routine radiographs. This study characterised micromotion of a tapered, cementless femoral stem and tantalum porous-coated vs. titanium acetabular shells in combination with highly cross-linked UHMWPE or conventional polyethylene liners using radiostereometric analysis (RSA) for 5 years following THR. Patients and Methods. This IRB-approved, prospective, double randomised, blinded study, involved 46 patients receiving a primary THR by a single surgeon. Each patient was randomised to receive a titanium (23) (Trilogy, Zimmer) or tantalum (23) (Modular Tantalum shell, Zimmer) uncemented hemispheric shell and either a highly-crosslinked or conventional polyethylene liner. Tantalum RSA markers were implanted in each patient. All patients had a Dorr A or B femoral canal and received a cementless, porous-coated titanium tapered stem (M/L Taper, Zimmer). All final femoral broaches were stable to rotational and longitudinal stress. RSA examinations, Harris Hip, UCLA, WOMAC, SF-12 scores were obtained at 10 days, 6 months, and annually through 5 years. Results. All patients demonstrated statistically significant improvement in Harris Hip, WOMAC, and SF-12 PCS scores post-operatively. Evaluation of polyethylene wear demonstrated that median penetration measurements were significantly greater in the conventional compared to the HXPLE liner cohorts at 1 year through 5 years follow-up (p<0.003). At 5 years, conventional liners showed 0.38 ± 0.05mm vertical wear whereas HXLPE liners showed 0.08 ± 0.02mm (p<0.003). Evaluation of the femoral stems demonstrated that the rate of subsidence was highest in the first 6 months (0.09mm/yr), with no other detectable motion through 5 years. Two outlying patients had significantly higher stem subsidence values at 6 months (0.7 mm and 1.0mm). One stem stabilised without further subsidence after 6 months (0.7mm), and the other stem stabilised at 1 year (1.5mm). Neither patient has clinical evidence of loosening. Evaluation of acetabular shells demonstrated less median vertical translation in tantalum than titanium shells at each time-point except at 3-years follow-up, however due to large standard errors, there was no significant difference between the two designs (p>0.05). These large standard errors were predominantly caused by two outliers, neither of which had clinical evidence of loosening. Discussion/Conclusion. In this RSA study of young THR patients, cementless tapered femoral stems, highly crosslinked polyethylene liners, and tantalum or titanium acetabular shells all demonstrated excellent performance through 5 years follow-up. Highly crosslinked polyethylene liners demonstrated significantly less wear than conventional liners. The femoral stem showed excellent stability through 5 years, with no clinical or radiologic episodes of failure. The small amount of micromotion seen is less than that previously reported for similar tapered, cementless stems and approaches the accuracy of RSA (0.05mm). Both acetabular shells demonstrated excellent stability with minimal micromotion at 5 years without significant differences in migration. All patients demonstrated significant clinical improvement in pain and function and additional RSA evaluation of these patients is planned

Trochlear geometry of modern femoral implants is designed for mechanical alignment (MA) technique for TKA. The biomechanical goal is to create a proximalised and more valgus trochlea to better capture the patella and optimize tracking. In contrast, Kinematic alignment (KA) technique for TKA respects the integrity of the soft tissue envelope and therefore aims to restore native articular surfaces, either femoro-tibial or femoro-patellar. Consequently, it is possible that current implant designs are not suitable for restoring patient specific trochlea anatomy when they are implanted using the kinematic technique, this could cause patellar complications, either anterior knee pain, instability or accelerated wear or loosening. The aim of our study is therefore to explore the extent to which native trochlear geometry is restored when the Persona^®implant (Zimmer, Warsaw, USA) is kinematically aligned.

A retrospective study of a cohort of 15 patients with KA-TKA was performed with the Persona^®prosthesis (Zimmer, Warsaw, USA). Preoperative knee MRIs and postoperative knee CTs were segmented to create 3D femoral models. MRI and CT segmentation used Materialise Mimics and Acrobot Modeller software, respectively. Persona^®implants were laser scanned to generate 3D implant models. Those implant models have been overlaid on the 3D femoral implant model (generated via segmentation of postoperative CTs) to replicate, in silico, the alignment of the implant on the post-operative bone and to reproduce in the computer models the features of the implant lost due to CT metal artefacts. 3D models generated from post-operative CT and pre-operative MRI were registered to the same coordinate geometry. A custom written planner was used to align the implant, as located on the CT, onto the pre-operative MRI based model. In house software enabled a comparison of trochlea parameters between the native trochlea and the performed prosthetic trochlea. Parameters assessed included 3D trochlear axis and anteroposterior offset from medial facet, central groove, and lateral facet. Sulcus angle at 30% and 40% flexion was also measured. Inter and intra observer measurement variabilities have been assessed.

Varus-valgus rotation between the native and prosthetic trochleae was significantly different (p<0.001), with the prosthetic trochlear groove being on average 7.9 degrees more valgus. Medial and lateral facets and trochlear groove were significantly understuffed (3 to 6mm) postoperatively in the proximal two thirds of the trochlear, with greatest understuffing for the lateral facet (p<0.05). The mean medio-lateral translation and internal-external rotation of the groove and the sulcus angle showed no statistical differences, pre and postoperatively.

Kinematic alignment of Persona^®implants poorly restores native trochlear geometry. Its clinical impact remains to be defined.

Introduction. The biomechanical behavior of lumbar spine instrumentation is critical in understanding its efficacy and durability in clinical practice. In this study, we aim to compare the biomechanics of the lumbar spine instrumented with single-level posterior rod and screw systems employing two distinct screw designs: paddle screw versus conventional screw system. Method. A fully cadaveric-validated 3D ligamentous model of the lumbopelvic spine served as the foundation for our comparative biomechanical analysis. 1. To simulate instrumentation, the intact spine was modified at the L4L5 level, employing either paddle screws or standard pedicle screws (SPS). The implants were composed of Ti-6AL-4V. Fixation at the S1 ensured consistency across loading scenarios. Loading conditions included a 400-N compressive load combined with a 10 N.m pure bending moment at the level of L1, replicating physiological motions of flexion-extension, lateral bending and axial rotation. We extracted data across various scenarios, focusing on the segmental range of motion at both implanted and adjacent levels. Result. In the flexion of L4L5, the applied force ranged from -29.2 to 29.3 N in the paddle screw, while it ranged from -25 to 25 N in the PS system. Similarly, the extension of L4L5 ranged from -3.1 to 2.6 N in the paddle and ranged from -4.5 to 3.9 N in the SPS system. In terms of stress distributions on the screw, stress concentrations decreased in several cases in the paddle design compared to the SPS systems. Top of Form. Conclusion. The paddle screw enhanced the range of motion overall in both the upper adjacent segment (L3L4) and the lower adjacent segment (L5S1) compared to the conventional SPS system. The stability of the aimed segment was increased by 33% on average with the paddle screw compared to conventional PS. Increasing the stability of the host segment decreases the possibility of non-union and the rate of fusion failure . 2.

Abstract. Objectives. To compare the effectiveness of phonophoresis (PH) and conventional therapeutic ultrasound (US) on the functional and pain outcomes of patients with knee osteoarthritis. Methods. We conducted an electronic search through PubMed, Cochrane Central Register of Clinical Trials (CENTRAL), Web of Science (WOS), and Scopus databases. We screened the retrieved articles to include only English full-text randomized controlled trials that examined the effect of phonophoresis versus conventional therapeutic ultrasound on patients with knee osteoarthritis. Two reviewers screened, extracted the data, and independently assessed the quality of the included articles. Results. A total of five randomized controlled trials met our inclusion criteria out of 267 studies screened. Our results showed no statistically significant differences between the PH and US groups (1), (2), (3),(4), and (5). The PH group demonstrated more significant effects than the UT group in reducing VAS pain scores (P=0.009) and improving WOMAC scores, although this did not reach the level of significance (P=0.143) (5). In the long term, PH therapy was found to be superior to US in improving painless walking duration and distance VAS scores (p=0.034, 0.017) respectively, as well as walking and resting walking VAS scores (p=0.03, 0.007) respectively, which were found to be permanent (3). Conclusions. Both therapies improve pain and function. However, we suggest conducting more high-quality trials with larger sample sizes and do not recommend the use of these therapies in clinical practice due to limitations in gender selection and high risk of bias. 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

The regenerative capacity of hyaline cartilage is greatly limited. To prevent the onset of osteoarthritis, cartilage defects have to be properly treated. Cartilage, tissue engineered by mean of bioactive glass (BG) scaffolds presents a promising approach. Until now, conventional BGs have been used mostly for bone regeneration, as they are able to form a hydroxyapatite (HA) layer and are therefore, less suited for cartilage reconstruction. The aim of this study is to compare two BGs based on a novel BG composition tailored specifically for cartilage (CAR12N) and patented by us with conventional BG (BG1393) with a similar topology. The highly porous scaffolds consisting of 100% BG (CAR12N, CAR12N with low Ca2+/Mg2+ and BG1393) were characterized and dynamically seeded with primary porcine articular chondrocytes (pACs) or primary human mesenchymal stem cells (hMSCs) for up to 21 days. Subsequently, cell viability, DNA and glycosaminoglycan contents, cartilage-specific gene and protein expression were evaluated. The manufacturing process led to a comparable high (over 80%) porosity in all scaffold variants. Ion release and pH profiles confirmed bioactivity for them. After both, 7 and 21 days, more than 60% of the total surfaces of all three glass scaffold variants was densely colonized by cells with a vitality rate of more than 80%. The GAG content was significantly higher in BG1393 colonized with pACs. In general, the GAG content was higher in pAC colonized scaffolds in comparison to those seeded with hMSCs. The gene expression of cartilage-specific collagen type II, aggrecan, SOX9 and FOXO1 could be detected in all scaffold variants, irrespectively whether seeded with pACs or hMSCs. Cartilage-specific ECM components could also be detected at the protein level. In conclusion, all three BGs allow the maintenance of the chondrogenic phenotype or chondrogenic differentiation of hMSCs and thus, they present a high potential for cartilage regeneration