bluuebunny/crossref_metadata_2025 huggingface dataset:
AN OSTEOCHONDRAL EXPLANT MODEL TO STUDY BONE CARTILAGE CROSSTALK IN PTOA
Authors: Amado I. , Hodgkinson T. , Mathavan N. , Murphy C.M. , Kennedy O.D.
Published: July 2023

Post-traumatic osteoarthritis (PTOA) is a subset of osteoarthritis, which occurs secondary to traumatic joint injury which is known to cause pathological changes to the osteochondral unit. Articular cartilage degradation is a primary hallmark of OA, and is normally associated with end-stage disease. However, subchondral bone marrow lesions are associated with joint injury, and may represent localized bone microdamage. Changes in the osteochondral unit have been traditionally studied using explant models, of which the femoral-head model is the most common. However, the bone damage caused during harvest can confound studies of microdamage. Thus, we used a novel patellar explant model to study osteochondral tissue dynamics and mechanistic changes in bone-cartilage crosstalk.

Firstly, we characterized explants by comparing patella with femoral head models. Then, the patellar explants (n=269) were subjected to either mechanical or inflammatory stimulus. For mechanical stimulus 10% strain was applied at 0.5 and 1 Hz for 10 cycles. We also studied the responses of osteochondral tissues to 10ng/ml of TNF-α or IL-1β for 24hrs.

In general the findings showed that patellar explant viability compared extremely well to the femoral head explant. Following IL-1β or TNF-α treatment, MMP13, significantly increased three days post exposure, furthermore we observed a decrease in sulfate glycoaminoglycan (sGAG) content. Bone morphometric analysis showed no significant changes. Contrastingly, mechanical stimulation resulted in a significant decrease sGAG particularly at 0.5Hz, where an increase in MMP13 release 24hrs post stimulation and an upregulation of bone and cartilage matrix degradation markers was observed. Furthermore, mechanical stimulus caused increases in TNF-α, MMP-8, VEGF expression.

In summary, this study demonstrates that our novel patella explant model is an excellent system for studying bone-cartilage crosstalk, which responds well to both mechanical and inflammatory stimulus and is thus of great utility in the study of PTOA.
UTILIZING SERIAL SECTION ELECTRON MICROSCOPY TO INTERROGATE STAPHYLOCOCCUS AUREUS BONE INFECTION
Authors: de Mesy Bentley K. , Galloway C. , Muthukrishnan G. , Masters E. , Zeiter S. , Schwarz E. , Leckenby J.
Published: July 2023

Serial section electron microscopy (SSEM) was initially developed to map the neural connections in the brain. SSEM eventually led to the term ‘Connectomics’ to be coined to describe process of following a cell or structure through a volume of tissue. This permits the true three-dimensionality to be appreciated and relationships between cells and structures. The purpose of this study was to utilize this methodology to interrogate S. aureus infected bone.

Bone samples were harvested from mice tibia infected with S. aureus and were fixed, decalcified, and osmicated. The samples were paraffin embedded and 5-micron sections were cut to identify regions of bacterial invasion into the osteocyte-lacuna-canalicular-network (OLCN). This area was cut from the paraffin block, deparaffinized, post-fixed and reprocessed into epoxy resin. Serial sections were cut at 60nm and collected onto Kapton tape utilizing the Automated Tape-collecting Ultramicrotome (ATUMtome) system. Samples were mounted onto 4” silicon wafers and post-stained with 2% uranyl acetate followed by 0.3% lead citrate and carbon coated. A ZEISS GeminiSEM 450 scanning electron microscope fitted with an electron backscatter diffusion detector was used to image the sections. The image stack was aligned and segmented using the open-source software, VASTlite.

264 serial sections were imaged, representing approximately 40 × 45 × 15-micron (x, y, z) volume of tissue. 70% of the canaliculi demonstrated infiltration by S. aureus.

This study demonstrates that SSEM can be applied to the skeletal system and provide a new solution to investigate the OLCN system. It is feasible that this methodology could be implemented to investigate why some canaliculi are resistant to colonization and potentially opens up a new direction for the prevention of chronic osteomyelitis. In order to make this a realistic target, automated segmentation methodologies utilizing machine learning must be developed and applied to the bone tissue datasets.
THE LIFETIME REVISION RISK OF UNICOMPARTMENTAL KNEE ARTHROPLASTY
Authors: Tay M.L. , Young S.W. , Hooper G.J. , Frampton C.M.
Published: July 2023

Unicompartmental knee arthroplasty (UKA) is associated with a higher risk of revision compared with total knee arthroplasty (TKA). The outcomes of knee arthroplasty are typically presented as implant survival or incidence of revision after a set number of years, which can be difficult for patients and clinicians to conceptualise. We aimed to calculate the ‘lifetime risk’ of revision for UKA as a more relatable estimate of risk projection over a patient's remaining lifetime, and make comparisons to TKA.
All primary UKAS performed from 1999 to 2019 (n=13,481) captured by the New Zealand Joint Registry (NZJR) were included. The lifetime risk of revision was calculated and stratified by age, gender and American Society of Anesthesiologists (ASA) status.
The lifetime risk of revision for UKA was highest in the youngest patients (46-50 years; 40.4%) and lowest in the oldest patients (86-90 years; 3.7%). Lifetime risk of revision was higher for females (range 4.3%-43.4% cf. males 2.9%-37.4%) and patients with higher ASA status (ASA 3-4 range 8.8%-41.2% cf. ASA 1 1.8%-29.8%), regardless of age. The lifetime risk of UKA was two-fold higher than TKA (ranging from 3.7%-40.4% UKA, 1.6%-22.4% TKA) across all age groups. Increased risk of revision in the younger patients was associated with aseptic loosening in both males and females, and pain in females. Periprosthetic joint infections (PJI) accounted for 4% of all UKA revisions, in contrast to 27% for TKA; risk of PJI was higher for males than females for both procedures.
The lifetime risk of revision is a more meaningful measure of arthroplasty outcomes and can aid with patient counselling prior to UKA. Findings from this study show the increased lifetime risk of UKA revision for younger patients, females and those with higher ASA status.
ROBOTIC ARM-ASSISTED SYSTEM FOR UNICOMPARTMENTAL KNEE ARTHROPLASTY IS ASSOCIATED WITH A LEARNING CURVE OF 11 CASES AND INCREASED OPERATING TIME
Authors: Tay M.L. , Carter M. , Bolam S.M. , Zeng N. , Young S.W.
Published: July 2023

Unicompartmental knee arthroplasty (UKA) has a higher risk of revision than total knee arthroplasty, particularly for low volume surgeons. The recent introduction of robotic-arm assisted systems has allowed for increased accuracy, however new systems typically have learning curves. The objective of this study was to determine the learning curve of a robotic-arm assisted system for UKA.

Methods A total of 152 consecutive robotic-arm assisted primary medial UKA were performed by five surgeons between 2017 and 2021. Operative times, implant positioning, reoperations and patient-reported outcome measures (PROMS; Oxford Knee Score, EuroQol-5D, and Forgotten Joint Score) were recorded.

There was a learning curve of 11 cases with the system that was associated with increased operative time (13 minutes, p<0.01) and improved insert sizing over time (p=0.03). There was no difference in implant survival (98.2%) between learning and proficiency phases (p = 0.15), and no difference in survivorship between ‘high’ and ‘low’ usage surgeons (p = 0.23) at 36 months. There were no differences in PROMS related to the learning curve. This suggested that the learning curve did not lead to early adverse effects in this patient cohort.

The introduction of a robotic-arm assisted UKA system led to learning curves for operative time and implant sizing, but there was no effect on patient outcomes at early follow- up. The short learning curve was independent of UKA usage and indicated that robotic-arm assisted UKA may be particularly useful for low-usage surgeons.
TWO-YEAR FOLLOW-UP STUDY FOR PATIENTS UNDERGOING VERTEBRAL BODY TETHERING FOR IDIOPATHIC SCOLIOSIS
Authors: Roser M. , Izatt M. , Labrom R. , Askin G. , Little P.
Published: July 2023

Anterior vertebral body tethering (AVBT) is a growth modulating procedure used to manage idiopathic scoliosis by applying a flexible tether to the convex surface of the spine in skeletally immature patients. The purpose of this study is to determine the preliminary clinical outcomes for an adolescent patient cohort.

18 patients with scoliosis were selected using a narrow selection criteria to undergo AVBT. Of this cohort, 11 had reached a minimum follow up of 2 years, 4 had reached 18 months, and 3 had reached 6 months. These patients all demonstrated a primary thoracic deformity that was too severe for bracing, were skeletally immature, and were analysed in this preliminary study of coronal plane deformity correction.

Using open-source image analysis software (ImageJ, NIH) PA radiographs taken pre-operatively and at regular follow-up visits post-operatively were used to measure the coronal plane deformity of the major and compensatory curves.

Pre-operatively, the mean age was 12.0 years (S.D. 10.7 – 13.3), mean Sanders score 2.6 (S.D. 1.8-3.4), all Risser 0 and pre-menarchal, with mean main thoracic Cobb angle of 52° (S.D. 44.2-59.8°). Post-operatively the mean angle decreased to 26.4° (S.D. 18.4-32°) at 1 week, 30.4° (S.D. 21.3-39.6°) at 2 months, 25.7° (S.D. 18.7-32.8°) at 6 months, 27.9° (S.D. 16.2-39.6°) at 12 months, and 36.8° (S.D. 22.6– 51.0°) at 18 months and 38.2° (S.D. 27.6-48.7°) at 2 years. The change in curve at 2 years post-operative was statistically significant (P=0.004).

There were 4 tether breakages identified that did not require return to theatre as yet, one patient underwent a posterior spinal instrumented fusion due to curve progression.

AVBT is a promising new growth modulation technique for skeletally immature patients with progressive idiopathic scoliosis. This study has demonstrated a reduction in scoliosis severity.
APOPTOSIS OCCURS IN ANTERIOR TALOFIBULAR LIGAMENT OF CHRONIC LATERAL ANKLE INSTABILITY: “ADD EVIDENCE FROM BENCH TO BED”
Authors: Kim Y-C. , Choi Y-H. , Cho S.H.
Published: July 2023

Chronic lateral ankle instability (CLAI) is treated operatively, whereas acute ligament injury is usually treated nonoperatively. Such treatments have been widely validated. Apoptosis is known to cause ligament degeneration; however, few reports have focused on the possible role of apoptosis in degeneration of ruptured lateral ankle ligaments. The aim of our study is to elucidate the apoptosis that occurs within anterior talofibular ligament (ATFL) to further validate current CLAI treatments by adducing molecular and cellular evidence.

Between March 2019 and February 2021, 50 patients were prospectively enrolled in this study. Ruptured ATFL tissues were collected from 21 CLAI patients (group C) and 17 acute ankle fracture patients (group A). Apoptotic cells were counted using the terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end-labeling (TUNEL) assay. Western blotting for caspases 3, 7, 8, and 9 and cytochrome c, was performed to explore intrinsic and extrinsic apoptotic pathways. Immunohistochemistry was used to detect caspases 3, 7, 8, and 9 and cytochrome c, in ligament vessel endothelial cells.

More apoptotic cells were observed in group C than group A in TUNEL assay. Western blotting revealed that the apoptotic activities of group C ligaments were significantly higher than those of group A (all p < 0.001). Immunohistochemistry revealed increased expression of caspases 3, 7, 8, and 9, and cytochrome c, in group C compared to group A.

The ATFL apoptotic activities of CLAI patients were significantly higher than those of acute ankle fracture patients, as revealed biochemically and histologically. Our data further validate current CLAI treatments from a molecular and cellular perspective. Efforts should be made to reverse or prevent ATFL apoptosis in CLAI patients.
DO OLDER PATIENTS SUSTAINING FRACTURE OF THE DISTAL RADIUS FOLLOWED UP IN FRACTURE CLINIC RECEIVE BONE HEALTH REVIEW?
Authors: Elbahi A. , Onazi O. , Ramadan M. , Hanif Y. , Eastley N. , Houghton-Clemmey R.
Published: July 2023

It is known that Osteoporosis is the pathology of bone mass and tissue loss resulting in an increase of fragility, risk of fracture occurrence, and risk of fracture recurrence. We noted there was no definitive pathway in our last audit, therefore recommended: availability of the Osteoporosis clinic referral form in an accessible place, the form be filled by the doctor reviewing the patient in the first fracture clinic, and a liaison nurse to ensure these forms were filled and sent to the Osteoporosis clinic. This second audit analyses our Trust's response to these recommendations and effect achieved in Osteoporosis care.

We reviewed our local data base from the 7/27/2020 – 10/2/2021 retrospectively for distal radius fractures who were seen in fracture clinic. We analysed a sample size of 59 patients, excluding patients who had already commenced bone protection medications.

67.7% of our patients had neither been on bone protection medications nor recorded referrals and 13.5% were already on bone protection medications when they sustained the fragility fracture. Ten out of the 51 patients were offered referral to the osteoporosis clinic, and one refused. This makes 20% (10 out of 50) of the patients had completed referrals. In comparison, in our first audit, 11% had already been on bone protection medications and 18% had completed referrals. The second cycle showed a slight increase in compliance. Majority of the referrals were completed by Orthopaedic Consultants in both audits and ana awareness increase noted among non-consultants in starting the referral process.

Based on our analysis, our Trust has a slight improvement in commencing bone protection medications, associated with slight improvement in completing referrals to the Osteoporosis clinic. Despite our recommendations in the first audit, there is still no easily accessible definitive pathway to ensure our Trust's patients have timely access to bone protection and continued care at the Osteoporosis clinic. We recommend streamlining our recommendations to have a more effective approach in ensuring our Trust meets national guidelines. We will implement a Yes or No question assessment for patients visiting clinic in our electronic database which should assist in referral completions.
THE BIOMECHANICAL ANALYSIS OF A NOVEL IMPLANT FOR SCAPHOLUNATE INTEROSSEOUS LIGAMENT RUPTURE REPAIR
Authors: Quinn A. , Pizzolato C. , Bindra R. , Lloyd D. , Saxby D.
Published: July 2023

There is currently no commercially available and clinically successful treatment for scapholunate interosseous ligament rupture, the latter leading to the development of hand-wrist osteoarthritis. We have created a novel biodegradable implant which fixed the dissociated scaphoid and lunate bones and encourages regeneration of the ruptured native ligament. To determine if scaphoid and lunate kinematics in cadaveric specimens were maintained during robotic manipulation, when comparing the native wrist with intact ligament and when the implant was installed.

Ten cadaveric experiments were performed with identical conditions, except for implant geometry that was personalised to the anatomy of each cadaveric specimen. Each cadaveric arm was mounted upright in a six degrees of freedom robot using k-wires drilled through the radius, ulna, and metacarpals. Infrared markers were attached to scaphoid, lunate, radius, and 3rd metacarpal. Cadaveric specimens were robotically manipulated through flexion-extension and ulnar-radial deviation by ±40° and ±30°, respectively.

The cadaveric scaphoid and lunate kinematics were examined with 1) intact native ligament, 2) severed ligament, 3) and installed implant.

Digital wrist models were generated from computed tomography scans and included implant geometry, orientation, and location. Motion data were filtered and aligned relative to neutral wrist in the digital models of each specimen using anatomical landmarks. Implant insertion points in the scaphoid and lunate over time were then calculated using digital models, marker data, and inverse kinematics. Root mean squared distance was compared between severed and implant configurations, relative to intact.

Preliminary data from five cadaveric specimens indicate that the implant reduced distance between scaphoid and lunate compared to severed configuration for all but three trials.

Preliminary results indicate our novel implant reduced scapho-lunate gap caused by ligament transection. Future analysis will reveal if the implant can achieve wrist kinematics similar to the native intact wrist.
A SYSTEMATIC REVIEW OF THE POTENTIAL VALUE OF SYNOVIAL FLUID BIOMARKERS TO PREDICT CLINICAL OUTCOMES IN CARTILAGE REPAIR TREATMENTS
Authors: Lineham B. , Altaie A. , Harwood P. , McGonagle D. , Pandit H. , Jones E.
Published: July 2023

Multiple biochemical biomarkers have been previously investigated for the diagnosis, prognosis and response to treatment of articular cartilage damage, including osteoarthritis (OA). Synovial fluid (SF) biomarker measurement is a potential method to predict treatment response and effectiveness. However, the significance of different biomarkers and their correlation to clinical outcomes remains unclear. This systematic review evaluated current SF biomarkers used in investigation of cartilage degeneration or regeneration in the knee joint and correlated these biomarkers with clinical outcomes following cartilage repair or regeneration interventions.

PubMed, Institute of Science Index, Scopus, Cochrane Central Register of Controlled Trials, and Embase databases were searched. Studies evaluating SF biomarkers and clinical outcomes following cartilage repair intervention were included. Two researchers independently performed data extraction and QUADAS-2 analysis. Biomarker inclusion, change following intervention and correlation with clinical outcome was compared.

9 studies were included. Study heterogeneity precluded meta-analysis. There was significant variation in sampling and analysis. 33 biomarkers were evaluated in addition to microRNA and catabolic/anabolic ratios. Five studies reported on correlation of biomarkers with six biomarkers significantly correlated with clinical outcomes following intervention. However, correlation was only demonstrated in isolated studies.

This review demonstrates significant difficulties in drawing conclusions regarding the importance of SF biomarkers based on the available literature. Improved standardisation for collection and analysis of SF samples is required. Future publications should also focus on clinical outcome scores and seek to correlate biomarkers with progression to further understand the significance of identified markers in a clinical context.
HIP FRACTURE IN SOLID ORGAN TRANSPLANT PATIENTS: OUTCOMES AND SURVIVORSHIP
Authors: Mariscal G. , Jover N. , Balfagón A. , Barrés M.
Published: July 2023

Solid organ transplant (SOT) recipients present an increased medical risk; however, few studies analyze the outcomes of these patients undergoing hip fracture surgery. This study aimes to determine the incidence of hip fracture in SOT patients and to compare the outcomes of SOT patients with matched non-SOT controls after hip fracture fixation.

A retrospective review identified 20 SOT patients with hip fracture at a single center from 2016 to 2021 and were matched (1:1) with a cohort of 20 patients with hip fracture without SOT. Patient outcomes, mortality/survival and clinical outcomes were compared between two groups.

The incidence of hip fracture in SOT patients was 20/1787, 1.1%. There were significant differences in mortality rate (73.3% SOT group vs. 26.7% non-SOT group; p<0.05). There were no differences in survival time (p=0.746). There were no differences in time to surgery (5.0 days SOT group vs. 3.1 days non-SOT group; p=0.109), however, there were significant differences in the hospital length of stay (14 days SOT group vs. 8.6 days non-SOT group; p=0.018). There were no differences regarding the complication rate between the two groups (9/20, 45% vs. 6/20, 30% in the SOT and non-SOT groups, respectively).

SOT patients with associated hip fracture required longer hospital length of stay than non-SOT patients. SOT patients did not show greater clinical complications; however, they presented higher mortality rate compared to non-SOT patients.
ORTHOPAEDIC SURGICAL DOCUMENTATION: PRE-TEMPLATED OPERATION NOTES SIGNIFICANTLY IMPROVE DOCUMENTATION OF SURGICAL PROCEDURES
Authors: Sneddon F. , Fritsch N. , Skipsey D. , Mackenzie S. , Rankin I.
Published: July 2023

The Royal College of Surgeons of England (RCS) Good Surgical Practice guidance identifies essential criteria for surgical operation note documentation. The current quality improvement project aims to identify if using pre-templated operation notes for documenting fractured neck of femur surgery results in improved documentation when compared to free hand orthopaedic operation notes.

A total of fourteen categories were identified from the RCS guidance as required across all the operations identified in this study. All operations for the month of October 2021 were identified and the operation notes analysed. Pre-templated operation notes were compared to free hand operation notes.

97 cases were identified, of which 74 were free hand operation notes and 23 were pre-templated fractured neck of femur operation notes. All fourteen categories were completed in 13 (57%) of the templated operation notes vs 0 (0%) in the free hand operation notes (odds ratio 0.0052, 95% CI 0.0003 to 0.0945, p < 0.001). The median total number of completed categories was significantly higher in the templated op-note group compared to the free hand op-note group (templated median 14, range 12-14, vs. free hand median 11, range 9 to 13, p < 0.001). Logistic regression analysis of operation notes written by Registrars or Consultants identified Registrars as more likely to document the antibiotic prophylaxis given (p = 0.025).

Use of pre-templated operation notes results in significantly improved documentation. Adoption of generic pre-templated operation notes to improve surgical documentation should be considered across all operations.
TOTAL HIP ARTHROPLASTY OUTCOMES AND PREOPERATIVE PATIENT PSYCHOLOGICAL FACTORS: A SYSTEMATIC REVIEW
Authors: Gagnier J. , O'Connor J.
Published: July 2023

We sought to determine the relationship between patient preoperative psychological factors and postoperative THA outcomes.

We performed an electronic search up to December 2021 using the following terms: “(mental OR psychological OR psychiatric) AND (function OR trait OR state OR predictor OR health) AND (outcome OR success OR recovery OR response) AND total joint arthroplasty)”. Peer-reviewed, English language studies regarding THA outcomes were analyzed for preoperative patient mental health metrics and objective postoperative results regarding pain, functionality and surgical complications. We extracted study data, assessed the risk of bias of included studies, grouped them by outcome measure and performed a GRADE assessment.

Seventeen of 702 studies fulfilled inclusion criteria and were included in the review. Overall, compared to cohorts with a normal psychological status, patients with higher objective measures of preoperative depression and anxiety reported increased postoperative pain, decreased functionality and greater complications following THA. Additionally, participants with lower self-efficacy or somatization were found to have worse functional outcomes. Following surgery, both early and late pain scores remained higher in patients with preoperative depression and anxiety.

Preoperative depression and anxiety may negatively impact patient reported postoperative pain, physical function and complications following THA. A meta-analysis was not performed because of the heterogeneity of studies, specifically the use of differing pain scales and measures of physical and psychological function as well as varied follow-up times. Future research could test interventions to treat pre-operative depression or anxiety and explore longitudinal outcomes in THA patients. Surgeons should consider the preoperative psychological status when counseling patients regarding expected surgical outcomes and attempt to treat a patient's depression or anxiety prior to undergoing total hip arthroplasty.
CHIN INCIDENCE: A NOVEL PREDICTOR OF CERVICAL SAGITTAL ALIGNMENT
Authors: Aljuaid M. , Alzahrani S. , Alswat M.
Published: July 2023

Cranio-cervical connection is a well-established biomechanical concept. However, literature of this connection and its impact on cervical alignment is scarce. Chin incidence (CI) is defined as a complementary to the angle between chin tilt (CHT) and C2 slope (C2S) axes. This study aims to investigate the relationship between cervical sagittal alignment parameters and CI with its derivatives.

A retrospective cross-sectional study carried out in a tertiary center. CT-neck radiographs of non-orthopedics patients were included. They had no history of spine related symptoms or fractures in cranium or pelvis. Images’ reports were reviewed to exclude those with tumors in the c-spine or anterior triangle of the neck.

A total of 80 patients was included with 54% of them were males. The mean of age was 30.96± 6.03. Models of predictability for c2-c7 cobb's angle (CA) and C2-C7 sagittal vertical axis (SVA) using C2S, CHT, and CI were significant and consistent r20.585 (f(df3,76) =35.65, P ≤0.0001, r=0.764), r20.474 (f(df2,77) =32.98, P ≤0.0001, r=-0.550), respectively. In addition, several positive significant correlations were detected in our model in relation to sagittal alignment parameters. Nonetheless, models of predictability for CA and SVA in relation to neck tilt (NT), T1 slope (T1S) and thoracic inlet axis (TIA) were less consistent and had a significant marginally weaker attributable effect on CA, however, no significant effect was found on SVA r20.406 (f(df1,78) =53.39, P ≤0.0001, r=0.620), r20.070 (f(df3,76) =1.904, P 0.19), respectively. Also, this study shows that obesity and aging are linked to decreased CI which will result in increasing SVA and ultimately decreasing CA.

CI model has a more valid attributable effect on the sagittal alignment in comparison to TIA model. Future investigations factoring this parameter might enlighten its linkage to many cervical spine diseases or post-op complications (i.e., trismus).
CERAMIC HIP RESURFACING ARTHROPLASTY SHOWS SIMILAR FUNCTIONAL GAIN TO METAL HIP RESURFACING ARTHROPLASTY
Authors: Maslivec A. , Leon D. , Cobb J.
Published: July 2023

Reports of improved functional outcome of Metal on Metal Hip Resurfacing Arthroplasty (mHRA) to Total Hip Replacement needs to be balanced with concerns of metal ion release. By removing cobalt-chrome, cHRA reduces these risks. To the author's knowledge, there is no data available on functional outcomes of cHRA, therefore the aim of the study was to compare the function between cHRA patients and mHRA patients.

24 patients received a unilateral cHRA (H1, Embody) and was compared to 24 age and gender matched patients with a unilateral mHRA (BHR, Smith and Nephew). All patients completed the Oxford Hip Score (OHS)[T2] and underwent gait analysis on an instrumented treadmill before and at a mean of 74wks (+/− 10) for mHRA and 53wks (+/− 2) for cHRA post op. Walking trials started at 4km/h and increased in 0.5km/h increments until a top walking speed (TWS) was achieved. Vertical ground reaction forces (GRF) were recorded along with the symmetry index (SI). Spatiotemporal measures of gait were also recorded. Vertical GRF were captured for the entire normalised stance phase using statistical parametric mapping (SPM; CI = 95%).

The gain in OHS was similar: H1 (25-46), BHR(27-47). TWS increased by 19% with H1 (6.02 – 8.0km/hr), and 20% with BHR (6.02 – 7.37km/hr). SPM of the entire gait cycle illustrated the restoration of symmetry in both groups with no difference in GRF across the stance phase between groups at 5km/hr pre-op and post-op. At faster speeds (6.5km/hr), H1 patients had a mid-support GRF slightly closer to normal compared to BHR. Both groups increased step length similar from pre to post op (H1:0.76 – 0.85cm, BHR:0.77-0.86cm).

In this study, subjective and objective functional outcome measures suggest that short term functional outcomes of ceramic resurfacing is not inferior to metal resurfacing.
ENGINEERING A TENDON-BONE ENTHESIS-MIMICKING HYBRID MATRIX FOR REPAIR OF IRREPARABLE ROTATOR CUFF TEARS
Authors: Mortimer J. , Tamaddon M. , Liu C.
Published: July 2023

Rotator cuff tears are common, with failure rates of up to 94% for large and massive tears1. For such tears, reattachment of the musculotendinous unit back to bone is problematic, and any possible tendon-bone repair heals through scar tissue rather than the specially adapted native enthesis. We aim to develop and characterise a novel soft-hard tissue connector device, specific to repairing/bridging the tendon-bone injury in significant rotator cuff tears, employing decellularised animal bone partially demineralised at one end for soft tissue continuation.

Optimisation samples of 15×10×5mm3, trialled as separate cancellous and cortical bone samples, were cut from porcine femoral condyles and shafts, respectively. Samples underwent 1-week progressive stepwise decellularisation and a partial demineralisation process of half wax embedding and acid bathing. Characterisations were performed histologically for the presence/absence of cellular staining in both peripheral and central tissue areas (n=3 for each cortical/cancellous, test/PBS control and peripheral/central group), and with BioDent reference point indentation (RPI) for pre- and post-processing mechanical properties.

Histology revealed absent cellular staining in peripheral and central cancellous samples, whilst reduced in cortical samples compared to controls. Cancellous samples decreased in wet mass after decellularisation by 45.3% (p<0.001). RPI measurements associated with toughness (total indentation depth, indentation depth increase) and elasticity (1st cycle unloading slope) showed no consistent changes after decellularisation. X-rays confirmed half wax embedding provided predictable control of the mineralised-demineralised interface position.

Initial optimisation trials show proof-of-concept of a soft-hard hybrid scaffold as an immune compatible xenograft for irreparable rotator cuff tears. Decellularisation did not appreciably affect mechanical properties, and further biological, structural and chemical characterisations are underway to assess validity before in vivo animal trials and potential clinical translation.
OSTEOTOMIES AROUND THE KNEE INTERFERE WITH ALIGNMENT OF THE HINDFOOT: KNEE SURGEONS SHOULD NOT FORGET THE ANKLE JOINT. A SYSTEMATIC REVIEW OF BIOMECHANICAL AND CLINICAL STUDIES
Authors: Van Oevelen A. , Burssens A. , Krähenbühl N. , Barg A. , Audenaert E. , Hintermann B. , Victor J.
Published: July 2023

Several emerging reports suggest an important involvement of the hindfoot alignment in the outcome of knee osteotomy. At present, studies lack a comprehensive overview. Therefore, we aimed to systematically review all biomechanical and clinical studies investigating the role of the hindfoot alignment in the setting of osteotomies around the knee.

A systematic literature search was conducted on multiple databases combining “knee osteotomy” and “hindfoot/ankle alignment” search terms. Articles were screened and included according to the PRISMA guidelines. A quality assessment was conducted using the Quality Appraisal for Cadaveric Studies (QUACS) - and modified methodologic index for non-randomized studies (MINORS) scales.

Three cadaveric, fourteen retrospective cohort and two case-control studies were eligible for review. Biomechanical hindfoot characteristics were positively affected (n=4), except in rigid subtalar joint (n=1) or talar tilt (n=1) deformity. Patient symptoms and/or radiographic alignment at the level of the hindfoot did also improve after knee osteotomy (n=13), except in case of a small pre-operative lateral distal tibia- and hip knee ankle (HKA) angulation or in case of a large HKA correction (>14.5°). Additionally, a pre-existent hindfoot deformity (>15.9°) was associated with undercorrection of lower limb alignment following knee osteotomy. The mean QUACS score was 61.3% (range: 46–69%) and mean MINORS score was 9.2 out of 16 (range 6–12) for non-comparative and 16.5 out of 24 (range 15–18) for comparative studies.

Osteotomies performed to correct knee deformity have also an impact on biomechanical and clinical outcomes of the hindfoot. In general, these are reported to be beneficial, but several parameters were identified that are associated with newly onset – or deterioration of hindfoot symptoms following knee osteotomy. Further prospective studies are warranted to assess how diagnostic and therapeutic algorithms based on the identified criteria could be implemented to optimize the overall outcome of knee osteotomy.

Remark: Aline Van Oevelen and Arne Burssens contributed equally to this work
OVINE KNEE KINEMATICS AND CONTACT PRESSURES OF A NOVEL FIBRE MATRIX-REINFORCED HYDROGEL TOTAL MENISCUS REPLACEMENT
Authors: Bartolo M.K. , Newman S. , Dandridge O. , Provaggi E. , Accardi M.A. , Dini D. , Amis A.A.
Published: July 2023

No proven long-term joint-preserving treatment options exist for patients with irreparable meniscal damage. This study aimed to assess gait kinematics and contact pressures of novel fibre-matrix reinforced polyvinyl alcohol-polyethylene glycol (PVA-PEG) hydrogel meniscus implanted ovine stifle joints against intact stifles in a gait simulator.

The gait simulator controlled femoral flexion-extension and applied a 980N axial contact force to the distal end of the tibia, whose movement was guided by the joint natural ligaments (Bartolo; ORS 2021;p1657- LB). Five right stifle joints from sheep aged >2 years were implanted with a PVA-PEG total medial meniscus replacement, fixed to the tibia via transosseous tunnels and interference screws. Implanted stifle joint contact pressures and kinematics in the simulator were recorded and compared to the intact group. Contact pressures on the medial and lateral condyles were measured at 55° flexion using Fujifilm Prescale Low Pressure film inserted under the menisci. 3D kinematics were measured across two 30 second captures using the Optotrak Certus motion-tracking system (Northern Digital Inc.).

Medial peak pressures were not significantly different between the implanted and intact groups (p>0.4), while lateral peak pressures were significantly higher in the implanted group (p<0.01). Implanted stifle joint kinematics in the simulator did not differ significantly from the intact baseline (p>0.01), except for in distraction-compression (p<0.01).

Our findings show that the fibre-matrix reinforced PVA-PEG hydrogel meniscal replacement restored the medial peak contact pressures. Similar to published literature (Fischenich; ABE 2018;46(11):1–12), the lateral peak pressures in the implanted group were higher than the intact. Joint kinematics were similar across groups, with slightly increased internal-external rotation in the implanted group. These findings highlight the effectiveness of the proposed approach and motivate future work on the development of a total meniscal replacement.
VIABILITY OF MESENCHYMAL STEM CELLS IS NOT AFFECTED BY SYRINGE PRESSURE INJECTION
Authors: Niessen L. , Wendlandt R. , Schulz A.P.
Published: July 2023

A promising application of Mesenchymal stem cells (MSCs) is the treatment of non-unions. Substituting bone grafts, MSCs are directly injected into the fracture gap. High cell viability seems to be a prerequisite for therapeutic success. Administration of the MSCs via injection creates shear stresses possibly damaging or destroying the cells.

Aim of this study was to investigate the effect of the injection process on cell viability.

MSCs were isolated and cultivated from femoral tissue of five subjects undergoing arthroplasty. Prior to injection, the cells were identified as MSCs. After dissolving to a concentration of 1 Million cells/ml, 1 ml of the suspension was injected through a cannula of 200 mm length and 2 mm diameter (14 G) with flow rates of 38 and 100 ml/min. The viability of the MSCs at different flow rates was evaluated by staining to detect the healthy cell fraction. It was analyzed statistically against a control group via the Kruskal-Wallis-test and for equivalence via the TOST procedure. Significance level was set to 5 %, equivalence margin to 20 %.

The healthy cell fraction of the control group was 85.88 ± 2.98 %, 86.04 ± 2.53 % at 38 ml/min and 85.48 ± 1.64 % at 100 ml/min. There was no significant difference between the fraction of healthy cells (p = 0.99) for different volume flows, but a significant equivalence between the control group and the two volume flows (38 ml/min: p = 0.002, 100 ml/min: p = 0.001).

When injecting MSC solutions, e.g. into a non-union, the viability of the injected cells does not deterioriate significant. The injecting technique is therefore feasible.
IDEAL STANDARDIZED PREPARATION PROTOCOL FOR PLATELET-RICH PLASMA WITH MAXIMUM PLATELET RECOVERY
Authors: Muthu S.
Published: July 2023

Platelet-rich plasma (PRP) has been demonstrated to benefit a variety of disciplines. But there exists heterogeneity in results obtained due to lack of standardization of the preparation protocols employed in them. We aim to identify and standardize a preparation protocol for PRP with maximum recovery of platelets to obtain reproducible results across studies.

Blood samples were collected from 20 healthy volunteers. The double spin protocol of PRP preparation was analyzed for variables such as centrifugal acceleration, time, and volume of blood processed and final product utilized. The final PRP prepared was investigated for platelet recovery, concentration, integrity, and viability.

We noted maximum platelet recovery (86-99%) with a mean concentration factor of 6-times baseline, with double centrifugation protocol at 100xg and 1600xg for 20 minutes each. We also noted that 10 ml of blood in a 15 ml tube was the ideal volume of blood to be processed to maximize platelet recovery. We demonstrated that the lower 1/3rd is the ideal volume to be utilized for clinical application. We did not note a loss of integrity or viability of the platelets in the final product from the above-said protocol.

Preparation of PRP by the double spin protocol of 10 ml of blood at 100xg and 1600xg for 20 minutes each in a 15ml tube and using the lower 1/3rd of the final product demonstrated consistent high platelet recovery (86-99%) and concentration (6x) without disturbing the platelet integrity or viability.
QUANTIFYING SLIDING DISTANCE DURING CAM-TYPE HIP IMPINGEMENT FOR A SET OF ACTIVITIES
Authors: Afzal T. , Jones A. , Williams S.
Published: July 2023

Cam-type femoroacetabular impingement is caused by bone excess on the femoral neck abutting the acetabular rim. This can cause cartilage and labral damage due to increased contact pressure as the cam moves into the acetabulum. However, the damage mechanism and the influence of individual mechanical factors (such as sliding distance) are poorly understood. The aim of this study was to identify the cam sliding distance during impingement for different activities in the hip joint.

Motion data for 12 different motion activities from 18 subjects, were applied to a hip shape model (selected as most likely to cause damage, anteriorly positioned with a maximum alpha angle of 80°). The model comprised of a pointwise representation of the acetabular rim and points on the femoral head and neck where the shape deviated from a sphere (software:Matlab).

The movement of each femoral point was tracked in 3D while an activity motion was applied, and impingement recorded when overlap between a cam point and the acetabular rim occurred. Sliding distance was recorded during impingement for each relevant femoral point.

Angular sliding distances varied for different activities. The highest mean (±SD) sliding distance was for leg-crossing (42.62±17.96mm) and lowest the trailing hip in golf swing (2.17±1.11mm). The high standard deviation in the leg crossing sliding distances, indicates subjects may perform this activity in a different manner.

This study quantified sliding distance during cam impingement for different activities. This is an important parameter for determining how much the hip moves during activities that may cause damage and will provide information for future experimental studies.
EXTRAPERITONEAL BLADDER RUPTURE REPAIR WITH OPEN REDUCTION INTERNAL FIXATION OF THE ANTERIOR PELVIC RING IS SAFE AND DECREASES INFECTION RISK
Authors: Saiz A. , O'Donnell E. , Kellam P. , Cleary C. , Moore X. , Schultz B. , Mayer R. , Amin A. , Gary J. , Eastman J. , Routt M.
Published: July 2023

Determine the infection risk of nonoperative versus operative repair of extraperitoneal bladder ruptures in patients with pelvic ring injuries.
Pelvic ring injuries with extraperitoneal bladder ruptures were identified from a prospective trauma registry at two level 1 trauma centers from 2014 to 2020. Patients, injuries, treatments, and complications were reviewed. Using Fisher's exact test with significance at P value < 0.05, associations between injury treatment and outcomes were determined.

Of the 1127 patients with pelvic ring injuries, 68 (6%) had a concomitant extraperitoneal bladder rupture.

All patients received IV antibiotics for an average of 2.5 days. A suprapubic catheter was placed in 4 patients. Bladder repairs were performed in 55 (81%) patients, 28 of those simultaneous with ORIF anterior pelvic ring. The other 27 bladder repair patients underwent initial ex-lap with bladder repair and on average had pelvic fixation 2.2 days later. Nonoperative management of bladder rupture with prolonged Foley catheterization was used in 13 patients. Improved fracture reduction was noted in the ORIF cohort compared to the closed reduction external fixation cohort (P = 0.04).

There were 5 (7%) deep infections. Deep infection was associated with nonoperative management of bladder rupture (P = 0.003) and use of a suprapubic catheter (P = 0.02). Not repairing the bladder increased odds of infection 17-fold compared to repair (OR 16.9, 95% CI 1.75 – 164, P = 0.01).

Operative repair of extraperitoneal bladder ruptures substantially decreases risk of infection in patients with pelvic ring injuries. ORIF of anterior pelvic ring does not increase risk of infection and results in better reductions compared to closed reduction. Suprapubic catheters should be avoided if possible due to increased infection risk later. Treatment algorithms for pelvic ring injuries with extraperitoneal bladder ruptures should recommend early bladder repair and emphasize anterior pelvic ORIF.
CLINICAL DIFFERENCES AMONG PERIPROSTHETIC AND NATIVE DISTAL FEMUR FRACTURES
Authors: Saiz A. , Kong S. , Bautista B. , Kelley J. , Haffner M. , Lee M.
Published: July 2023

With an aging population and increase in total knee arthroplasty, periprosthetic distal femur fractures (PDFFs) have increased. The differences between these fractures and native distal femur fractures (NDFF) have not been comprehensively investigated. The purpose of this study was to compare the demographic, fracture, and treatment details of PDFFs compared to NDFFs.

A retrospective study of patients ≥ 18 years old who underwent surgical treatment for either a NDFF or a PDFF from 2010 to 2020 at a level 1 trauma center was performed. Demographics, AO/OTA fracture classification, quality of reduction, fixation constructs, and unplanned revision reoperation were compared between PDFF patients and NDFF patients using t-test and Fisher's exact test.
209 patients were identified with 70 patients having a PDFF and 139 patients having a NDFF. Of note, 48% of NDFF had a concomitant fracture of the ipsilateral knee (14%) or tibial plateau (15%). The most common AO/OTA classification for PDFFs was 33A3.3 (71%). NDFFs had two main AO/OTA classifications of 33C2.2 (28%) or 33A3.2. (25%). When controlling for patient age, bone quality, fracture classification, and fixation, the PDFF group had increased revision reoperation rate compared to NDFF (P < 0.05).

PDFFs tend to occur in elderly patients with low bone quality, have complete metaphyseal comminution, and be isolated; whereas, NDFF tend to occur in younger patients, have less metaphyseal comminution, and be associated with other fractures. When controlling for variables, PDFF are at increased risk of unplanned revision reoperation. Surgeons should be aware of these increased risks in PDFFs and future research should focus on these unique fracture characteristics to improve outcomes.
FULLY CHARACTERIZING SPINAL LOAD DISPLACEMENT BEHAVIOUR USING VISCOELASTIC MODELS
Authors: Hayward S. , Miles A. , Keogh P. , Gheduzzi S.
Published: July 2023

Lower back pain (LBP) is a global problem. Countless in vitro studies have attempted to understand LBP and inform treatment protocols such as disc replacement devices (DRDs). A common method of reporting results is applying a linear fit to load-displacement behaviour, reporting the gradient as the specimen stiffness in that axis. This is favoured for speed, simplicity and repeatability but neglects key aspects including stiffening and hysteresis. Other fits such as polynomials and double sigmoids better address these characteristics, but solution parameters lack physical representation. The aim of this study was to implement an automated method to fit spinal load-displacement behaviour using viscoelastic models.

Six porcine lumbar spinal motion segments were dissected to produce isolated disc specimens. These were potted in Wood's metal, ensuring the disc midplane remained horizontal, sprayed with 0.9% saline and wrapped in saline-soaked tissue and plastic wrap to prevent dehydration. Specimens were tested using the University of Bath spine simulator operating under position control with a 400N axial preload.

Specimens were approximated using representative viscoelastic elements. These models were constructed in MATLAB Simulink R2020b using the SimScape library. Solution coefficients were determined by minimizing the sum of squared errors cost function using a non-linear least squares optimization method.

The models matched experimental data well with a mean % difference in model and specimen enclosed area below 6% across all axes. This indicates the ability of the model to accurately represent energy dissipated. The final models demonstrated reduced RMSEs factors of 3.6, 1.1 and 9.5 smaller than the linear fits for anterior-posterior shear, mediolateral shear and axial rotation respectively.

These nonlinear viscoelastic models exhibit significantly increased qualities of fit to spinal load-displacement behaviour when compared to linear approximations. Furthermore, they have the advantage of solution parameters which are directly linked to physical elements: springs and dampers. The results from this study could be instrumental in improving the design of DRDs as a mechanism for treating LBP.