Introduction and Objective

Scapholunate instability is the most common cause of carpal instability. When this instability is left untreated, the mechanical relationship between the carpal bones is permanently disrupted, resulting in progressive degenerative changes in the radiocarpal and midcarpal joints. Different tenodesis methods are used in the treatment of acute or early chronic reducible scapholunate instability, where arthritis has not developed yet and the scapholunate ligament cannot be repaired. Although it has been reported that pain is reduced in the early follow up in clinical studies with these methods, radiological results differ between studies. The deterioration of these radiological parameters is associated with wrist osteoarthritis as previously stated. Therefore, more studies are needed to determine the tenodesis method that will improve the wrist biomechanics better and will last longer. In our study, two new tenodesis methods, spiral antipronation tenodesis, and anatomic front and back reconstruction (ANAFAB) were radiologically compared with triple ligament tenodesis (TLT), in the cadaver wrists.

Abstract

To address the current challenge of anterior cruciate ligament (ACL) reconstruction, this study is the first to fabricate a braided collagen rope (BCR) which mimics native hamstring for ACL reconstruction. The study aims to evaluate the biological and biomechanical properties of BCR both in vivo and vitro. Rabbit ACL reconstruction model using collagen rope and autograft (hamstring tendon) was conducted. The histological and biomechanical evaluations were conducted at 6-, 12-, 18, 26-week post-operation. In vitro study included cell morphology analysis, cell function evaluation and RNA sequencing of the tenocytes cultured on BCR. A cadaver study was also conducted to verify the feasibility of BCR for ACL reconstruction. BCR displays satisfactory mechanical strength similar to hamstring graft for ACL reconstruction in rabbit. Histological assessment showed BCR restore ACL morphology at 26 weeks similar to native ACL. The superior dynamic ligamentization in BCR over autograft group was evidenced by assessment of cell and collagen morphology and orientation. The in vitro study showed that the natural collagen fibres within BCR enables to signal the morphology adaptation and orientation of human tenocytes in bioreactor. BCR enables to enhance cell proliferation and tenogenic expression of tenocytes as compared to hydrolysed collagen. We performed an RNA-Sequencing (RNA-seq) experiment where RNA was extracted from tenocyte seeded with BCR. Analysis of enriched pathways of the up-regulated genes revealed that the most enriched pathways were the Hypoxia-inducible factor 1-alpha (HIF1A) regulated networks, implicating the possible mechanism BCR induced ACL regeneration. The subsequent cadaver study was conducted to proof the feasibility of BCR for ACL reconstruction. This study demonstrated the proof-of-concept of bio-textile braided collagen rope for ACL reconstruction, and the mechanism by which BCR induces natural collagen fibres that positively regulate morphology and function of tenocytes

Proximal humeral shaft fractures are commonly treated with long straight locking plates endangering the radial nerve distally. The aim of this study was to investigate the biomechanical competence in a human cadaveric bone model of 90°-helical PHILOS plates versus conventional straight PHILOS plates in proximal third comminuted humeral shaft fractures. Eight pairs of humeral cadaveric humeri were instrumented using either a long 90°-helical plate (group1) or a straight long PHILOS plate (group2). An unstable proximal humeral shaft fracture was simulated by means of an osteotomy maintaining a gap of 5cm. All specimens were tested under quasi-static loading in axial compression, internal and external rotation as well as bending in 4 directions. Subsequently, progressively increasing internal rotational loading until failure was applied and interfragmentary movements were monitored by means of optical motion tracking. Flexion/extension deformation (°) in group1 was (2.00±1.77) and (0.88±1.12) in group2, p=0.003. Varus/valgus deformation (°) was (6.14±1.58) in group1 and (6.16±0.73) in group2, p=0.976. Shear (mm) and displacement (°) under torsional load were (1.40±0.63 and 8.96±0.46) in group1 and (1.12±0.61 and 9.02±0.48) in group2, p≥0.390. However, during cyclic testing shear and torsional displacements and torsion were both significantly higher in group 1, p≤0.038. Cycles to catastrophic failure were (9960±1967) in group1 and (9234±1566) in group2, p=0.24. Although 90°-helical plating was associated with improved resistance against varus/valgus deformation, it demonstrated lower resistance to flexion/extension and internal rotation as well as higher flexion/extension, torsional and shear movements compared to straight plates. From a biomechanical perspective, 90°-helical plates performed inferior compared to straight plates and alternative helical plate designs with lower twist should be investigated in future paired cadaveric studies

An international Consensus Group has by a Delphi approach identified the topic of host factors affecting pin site infection to be one of the top 10 priorities in external fixator management. The aim of this study was to report the frequency of studies reporting on specific host factors as a significant association with pin site infection. Host factors to be assessed was: age, smoking, BMI and any comorbidity, diabetes, in particular. The intention was an ethological review, data was extracted if feasible, however no meta-analysis was performed. A systematic literature search was performed according to the PRISMA-guidelines. The protocol was registered before data extraction in PROSPERO. The search string was based on the PICO criterias. A logic grid with key concept and index terms was made. A search string was built assisted by a librarian. The literature search was executed in three electronic bibliographic databases, including Embase MEDLINE (1111 hits) and CINAHL (2066 hits) via Ovid and Cochrane Library CENTRAL (387 hits). Inclusion criteria: external fixation, >1 pin site infection, host factor of interest, peer-reviewed journal. Exclusion criteria: Not written in English, German, Danish, Swedish, or Norwegian, animal or cadaveric studies, location on head, neck, spine, cranium or thorax, editorials or conference abstract. The screening process was done using Covidence. A total of 3564 titles found. 3162 excluded by title and abstract screening. 140 assessed for full text eligibility. 11 studies included for data extraction. The included studies all had a retrospective design. Three identified as case-control studies. Generally the included studies was assessed to have a high risk of bias. A significant associations between pin site infection for following host factors: a) increased HbA1C level in diabetic patients; b) congestive heart failure in diabetic patients; c) less co-morbidity; d) preoperative osteomyelitis was found individually. This systematic literature search identified a surprisingly low number of studies examining for risk of pin site infection and host factors. Thus, this review most of all serves to demonstrate a gap of evidence about correlation between host factors and risk of pin site infection, and further studies are warranted

To create a comprehensive, user-friendly, database that facilitates selection of optimized animal models for fracture research. Preclinical testing using research animal models can expedite effective and safe interventions for clinical fracture patients but ethical considerations (e.g., adherence to 3R humane principles) and failure to meet critical review (e.g., clinical translation, reproducibility) currently complicate the model selection process. English language publications (1980-2021) were derived from PubMed® using the search-term ‘bone and fracture and animal’. Clinical cases, reviews, and cadaver studies were excluded. Qualifying papers reporting use of fracture models had the following data transcribed: Author, journal, abstract, summary data, animal data, bone, focus (e.g., allograft) and model (e.g., articular fracture). Publications were quantitatively scored (1 star [very poor] – 5 stars [excellent]) for reproducibility, clinical translation and animal welfare. 4602 papers were derived from 677 journals from 177 publishers. Number of annual publications progressively increased from 18 (1980), peaking in 2015 (250) before substantially declining in 2020 (121) and 2021 (51). Descriptors (low to high) included 15 species (frog [1]–rat [1586]), 24 bones (phalanx [1]–femur [1646]), 134 research foci (bioprinting [4]–fracture healing [3533]), and 37 fracture models (avulsion [4]–diaphyseal [2113]). Percent of total publications scoring 1 or more stars for reproducibility, clinical translation and animal welfare ranged from: 1.0–5.8% (1 star), 5.9–30.6% (2 star), 21.3–42.8% (3 star), 19.2–44.4% (4 stars), and 1.3–26.7% (5 stars). FRAMD provides a dedicated resource that enhances selection of animal models that pertain to researchers’ fracture focus while being clinically relevant, reproducible and humane. FRAMD will help improve scientific data, reduce unnecessary use of animals, heighten workplace efficiency, and reduce cost by avoiding ill-suited or outdated models. FRAMD may particularly benefit grant writers and organizations seeking ‘best-practice’ assurance (e.g., funding agencies, academic research societies, CROs)

Abstract. Objective. A common orthopaedic pain found in a wide spectrum of individuals, from young and active to the elderly is anterior knee pain (AKP). It is a multifactorial disorder which is thought to occur through muscular imbalance, overuse, trauma, and structural malalignment. Over time, this can result in cartilage damage and subsequent chondral lesions. Whilst the current gold standard for chondral lesion detection is MRI, it is not a highly sensitive tool, with around 20% of lesions thought to be mis-diagnosed by MRI. Single-photon emission computerised tomography with conventional computer tomography (SPECT/CT) is an emerging technology, which may hold clinical value for the detection of chondral lesions. SPECT/CT may provide valuable diagnostic information for AKP patients who demonstrate absence of structural change on other imaging modalities. This review systematically assessed the value of SPECT/CT as an imaging modality for knee pain, and its ability to diagnose chondral lesions for patients who present with knee pain. Methods. Using PRISMA guidelines, a systematic search was carried out in PubMed, Science Direct, and Web of Knowledge, CINAHL, AMED, Ovid Emcare and Embase. Inclusion criteria consisted of any English language article focusing on the diagnostic value of SPECT/CT for knee chondral lesions and knee pain. Furthermore, animal or cadaver studies, comparator technique other than SPECT/CT or patients with a pathology other than knee chondral lesions were excluded from the study. Relevant articles underwent QUADAS-2 bias assessment. Results. 11,982 manuscripts were identified, and the titles were screened for relevance. Seven studies were selected as being appropriate and were subjected to QUADAS-2 assessment. All 7 articles scored low for bias. Two papers deemed that the ICRS score of chondral lesions at intraoperative assessment correlated with SPECT/CT tracer uptake. Two studies concluded that MRI significantly correlated with SPECT/CT tracer uptake, with some instances whereby SPECT/CT identified more chondral lesions than MRI. Two papers compared bone scintigraphy (BS) to SPECT/CT and concluded that SPECT/CT was not only able to identify more chondral lesions than BS, but also localise and characterise the lesions. Conclusion. Evidence implies that SPECT/CT may be a useful imaging modality for the detection and localisation of cartilage lesions, particularly in discrepant cases whereby there is an absence of lesions on other imaging modalities, or a lack of correspondence with patients’ symptoms. More studies would be of value to confirm the conclusions of this review. 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. Objectives. A damaged vertebral body can exhibit accelerated ‘creep’ under constant load, leading to progressive vertebral deformity. However, the risk of this happening is not easy to predict in clinical practice. The present cadaveric study aimed to identify morphometric measurements in a damaged vertebral body that can predict a susceptibility to accelerated creep. Methods. Mechanical testing of 28 human spinal motion segments (three vertebrae and intervening soft tissues) showed how the rate of creep of a damaged vertebral body increases with increasing “damage intensity” in its trabecular bone. Damage intensity was calculated from vertebral body residual strain following initial compressive overload. The calculations used additional data from 27 small samples of vertebral trabecular bone, which examined the relationship between trabecular bone damage intensity and residual strain. Results. Calculations from trabecular bone samples showed a strong non-linear relationship between residual strain and trabecular bone damage intensity (R. 2. = 0.78, P < 0.001). In damaged vertebral bodies, damage intensity as calculated from residual strain was then related to vertebral creep rate (R. 2. = 0.39, P = 0.001). This procedure enabled accelerated vertebral body creep to be predicted from morphological changes (residual strains) in the damaged vertebral body. Conclusion. These findings suggest that morphometric measurements obtained from fractured vertebrae can be used to quantify vertebral damage intensity and hence to predict progressive vertebral deformity

Understanding the long-term effects of total knee arthroplasty (TKA) on joint kinematics is vital to assess the success of the implant design and surgical procedure. However, while in vitro cadaveric studies quantifying post-operative biomechanics primarily reflect joint behaviour immediately after surgery,. 1. in vivo studies comprising of follow-up TKA patients often reflect joint behaviour a few months after surgery. 2. Therefore, the aim of this cadaveric study was to explore the long-term effects of TKA on tibiofemoral kinematics of a donor specimen, who had already undergone bilateral TKA, and compare them to post-operative kinematics reported in the literature. Two fresh-frozen lower limbs from a single donor (male, age: 83yr, ht: 1.83m, wt: 86kg), who had undergone bilateral TKA (Genesis II, Smith&Nephew, Memphis, USA) 19 years prior to his demise, were obtained following ethical approval from the KU Leuven institutional board. The specimens were imaged using computed tomography (CT) and tested in a validated knee simulator. 3. replicating active squatting and varus-valgus laxity tests. Tibiofemoral kinematics were recorded using an optical motion capture system and compared to various studies in the literature using the same implant – experimental studies based on cadaveric specimens (CAD). 1,4. and an artificial specimen (ART). 5. , and a computational study (COM). 6. . Maximum tibial abduction during laxity tests for the left leg (3.54°) was comparable to CAD (3.30°), while the right leg exhibited much larger joint laxity (8.52°). Both specimens exhibited valgus throughout squatting (left=2.03±0.57°, right=5.81±0.19°), with the change in tibial abduction over the range of flexion (left=1.89°, right=0.64°) comparable to literature (CAD=1.28°, COM=2.43°). The left leg was externally rotated (8.00±0.69°), while the right leg internally rotated (−15.35±1.50°), throughout squatting, with the change in tibial rotation over the range of flexion (left=2.61°, right=4.79°) comparable to literature (CAD=5.52°, COM=4.15°). Change in the femoral anteroposterior translation over the range of flexion during squatting for both specimens (left=14.88mm, right=6.76mm) was also comparable to literature (ART=13.40mm, COM=20.20mm). Although TKA was reportedly performed at the same time on both legs of the donor by the same surgeon, there was a stark difference in their post-operative joint kinematics. A larger extent of intraoperative collateral ligament release could be one of the potential reasons for higher post-operative joint laxity in the right leg. Relative changes in post-operative tibiofemoral kinematics over the range of squatting were similar to those reported in the literature. However, differences between absolute magnitudes of joint kinematics obtained in this study and findings from the literature could be attributed to different surgeons performing TKA, with presumable variations in alignment techniques and/or patient specific instrumentation, and the slightly dissimilar ranges of knee flexion during squatting. In conclusion, long-term kinematic effects of TKA quantified using in vitro testing were largely similar to the immediate post-operative kinematics reported in the literature; however, variation in the behaviour of two legs from the same donor suggested that intraoperative surgical alterations might have a greater effect on joint kinematics over time

Abstract. Objectives. Unicompartmental (UKA) and bicompartmental (BCA) knee arthroplasty are associated with improved functional outcomes compared to Total Knee Arthroplasty (TKA) in suitable patients, although the reason is poorly understood. The aim of this study was to measure how the different arthroplasties affect knee extensor function. Methods. Extensor function was measured for sixteen cadaveric knees and then re-tested following the different arthroplasties. Eight knees underwent medial UKA then BCA, then posterior-cruciate retaining TKA, and eight underwent the lateral equivalents then TKA. Extensor efficiency was calculated for ranges of knee flexion associated with common activities of daily living. Data were analyzed with repeated measures analysis of variance (α=0.05). Results. Compared to native, no differences were detected in either extensor moment or efficiency following UKA. Conversion to BCA resulted in a small drop in extensor moment between 70-90° flexion (p<0.05), but when examined in the context of daily activity ranges of flexion, extensor efficiency was largely unaffected. Following TKA, large decreases in extensor moment were measured at low knee flexion angles (p<0.05), resulting in 8–43% reduction in extensor efficiency for daily activity ranges. Conclusion. This cadaveric study found that TKA is associated with inferior extensor function compared to UKA and BCA. This may, in part, help explain the reported differences in function and satisfaction differences between partial and total knee arthroplasty. Declaration of Interest. (a) fully declare any financial or other potential conflict of interest

Abstract. Objectives. Hip joint laxity after total hip arthroplasty (THA) has been considered to cause microseparation and lead to complications, including wear and dislocation. In the native hip, the hip capsular ligaments may tighten at the limits of range of hip motion and provide a passive stabilising force preventing edge loading and reduce the risk of dislocation. Previous attempts to characterise mechanical properties of hip capsular ligaments have been largely variable and there are no cadaveric studies quantifying the force contributions of each ligament in different hip positions. In this study we quantify the passive force contribution of the hip capsular ligaments throughout a complete range of motion (ROM). Methods. Nine human cadaveric hip specimens (6 males and 3 females) with mean age of (76.4 ± 9.0 years) were skeletonised, preserving the capsular ligaments. Prepared specimens were tested in a 6 degree of freedom system to assess ROM with 5 Nm torque applied in external and internal rotation throughout hip flexion and extension. Capsular ligaments were resected in a stepwise fashion to assess internal force contributions of the iliofemoral (superior and inferior), pubofemoral, and ischiofemoral ligaments during ROM. Results. In external rotation, the superior and inferior iliofemoral ligament minimum force contributions were (136.52 ± 27.15 N) in flexion and (82.40 ± 27.85 N) in extension, respectively. In internal rotation, the ischiofemoral ligament force contributions were dominant in adducted-flexion positions and abducted-extension positions. Conclusions. These findings provide insights into the primary capsular structures that stabilise the hip joint in different manoeuvres. This data allows for an improved understanding of which capsular ligaments contribute the most to hip stability and has important implications for choosing surgical approaches and repair strategies to minimise complications related to joint instability. 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. Objectives. Clavicle fractures are common, yet debate exists regarding which patients would benefit from conservative versus operative management. Traditionally shortening greater than 2cm has been accepted as an indicator for surgery. However, clavicle length varies between individuals. In a cadaveric study clavicle shortening greater than 15% was suggested to affect outcomes. There is no clinical correlation of this in the literature. In this study we investigate outcomes following middle third clavicle fractures and the effect of percentage shortening on union rates. Methods. We identified a consecutive series of adults with primary midshaft clavicle fractures presenting to our institution from April 2015-March 2017. Clinical records and radiographs were reviewed to elicit outcomes. Time to union was measured against factors including; percentage shortening, displacement, comminution and smoking. Statistical significance was calculated. Results. 127 patients were identified, of whom 90 were managed conservatively and 37 operatively. Fractures were displaced in 86 patients (68%). Mean age was 41.7 years (range 18–89). Mean time to union for displaced fractures was longer than for undisplaced at 13.4 and 8.9 weeks respectively (p=0.0948). Displaced fractures treated operatively had mean time to union of 12.8 weeks, three weeks shorter than those managed conservatively (p=0.0470). Mean time to union for fractures with >15% shortening was 16.0 weeks, nearly double the 8.7 weeks with <15% shortening (p= 0.0241). Smokers had 8 weeks longer time to union (p=0.0082). Nonunion rate was 10% in fractures managed conservatively and 0% in those treated operatively. Complications following operative management were plate removal (13.5%), frozen shoulder (8.1%) and infection (2.9%). Conclusions. Nonunion rate is higher in fractures managed conservatively. Shortening >15% leads to significantly longer union time and should therefore be used as an indicator for surgery. Displacement and smoking also lengthen time to union and should be considered in the operative decision process. 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

It is common belief that consolidated intramedullary nailed trochanteric femur fractures can result in secondary midshaft or supracondylar fractures, involving the distal screws, when short or long nails are used, respectively. In addition, limited data exists in the literature to indicate when short or long nails should be selected for treatment. The aim of this biomechanical cadaveric study was to investigate short versus long Trochanteric Femoral Nail Advanced (TFNA) fixation in terms of construct stability and generation of secondary fracture pattern following trochanteric fracture consolidation. Eight intact human cadaveric femur pairs were assigned to 2 groups of 8 specimens each for nailing using either short or long TFNA with blade as head element. Each specimen was first biomechanically preloaded at 1 Hz over 2000 cycles in superimposed synchronous axial compression to 1800 N and internal rotation to 11.5 Nm. Following, internal rotation to failure was applied over an arc of 90° within 1 second under 700 N axial load. Torsional stiffness, torque at failure, angle at failure and energy at failure were evaluated. Fracture patterns were analyzed. Outcomes in the groups with short and long nails were 9.7±2.4 Nm/° and 10.2±2.9 Nm/° for torsional stiffness, 119.8±37.2 Nm and 128.5±46.7 Nm for torque at failure, 13.5±3.5° and 13.4±2.6° for angle at failure, and 887.5±416.9 Nm° and 928.3±461.0 Nm° for energy at failure, respectively, with no significant differences between them, P≥0.167. Fractures through the distal locking screw occurred in 5 and 6 femora instrumented with short and long nails, respectively. Fractures through the lateral entry site of the head element were detected in 3 specimens within each group. For short nails, fractures through the distal shaft region, not interfacing with the implant, were detected in 3 specimens. From biomechanical perspective, the risk of secondary peri-implant fracture after intramedullary nailed trochanteric fracture consolidation is similar when using short or long TFNA. Moreover, for both nail versions the fracture pattern does not unexceptionally involve the distal locking screw

Introduction and Objective. After anterior cruciate ligament reconstruction one of the risk factors for graft (re-)rupture is an increased posterior tibial slope (PTS). The current treatment for PTS is a high tibial osteotomy (HTO). This is a free-hand method, with 1 degree of tibial slope correction considered to be equal to 1 or even 1.67 mm of the anterior wedge resection. Error rates in the frontal plane reported in literature vary from 1 – 8.6 degrees, and in the sagittal plane outcomes in a range of 2 – 8 degrees are reported when planned on PTSs of 3 – 5 degrees. Therefore, the free-hand method is considered to have limited accuracy. It is expected that HTO becomes more accurate with patient specific saw guides (PSGs), with an accuracy margin reported in literature of 2 degrees. This proof of concept porcine cadaver case study aimed to investigate whether the use of PSGs improves the accuracy of HTO to less than 2 degrees. Secondly, the reproducibility of tibial slope measurement was evaluated. Materials and Methods. Preoperative MRI images of porcine cadaver knees (n = 3) were used to create 3D anatomical bone models (Mimics, Materialise, Belgium). These 3D models were subsequently used to develop PSGs (3-Matic, Materialise, Belgium) to correct all tibias for 3 degrees PTS and 4 degrees varus. The PSG mediated HTOs were performed by an experienced orthopaedic surgeon, after which postoperative MRI images were obtained. 3D anatomical models of postoperative tibias were created, and tibial slopes were assessed on both pre- and postoperative tibias. The tibial slope was defined as the angle between the mechanical axis and 3D tibial reference plane in the frontal and sagittal plane. The accuracy of the PSG mediated HTO (median and range) was defined as the difference in all possible combinations of the preoperatively planned and postoperatively obtained tibial slopes. To ensure reproducibility, the pre- and postoperative tibial slopes were measured thrice by one observer. The intra-class correlation coefficients (ICCs) were subsequently calculated to assess the intra-rater reliability (SPSS, IBM Corp., Armonk, N.Y., USA). Results. An accuracy within 2 degrees was achieved in all three cases. The median and range in accuracy for each specimen were +0.46 (−0.57 – 1.45), +0.60 (−1.07 – 1.00), and +0.45 (−0.16 – 0.71) degrees in the frontal plane, and −0.45 (−1.97 – 1.22), −0.80 (−2.42 – 1.77), and 0.00 (−2.19 – 1.93) degrees in the sagittal plane. The pre- and postoperatively planned tibial slopes in the frontal and sagittal plane were measured with a good up to excellent reproducibility. The ICCs of the preoperative planned tibial slopes were 0.82 (95% CI, 0.11 – 1.0), and 0.77 (95% CI, 0.17 – 1.0) for the frontal and sagittal plane, respectively. Postoperative, the ICC for the frontal plane was 0.92 (95% CI, 0.43 – 1.0), and 0.67 (95% CI, −0.06 – 0.99) for the sagittal plane. Conclusions. This proof of concept porcine case study showed an accuracy for the PSG mediated HTO within 2 degrees for each specimen. Moreover, the tibial slopes were measured with a good up to excellent reproducibility. Therefore, the PSG mediated HTO seems to be accurate and might be better than the current used free-hand HTO method. These results offer perspective for implementation of PSG mediated HTO to correct PTS and metaphyseal varus

The treatment of scapholunate (SL) ligament injuries is addressed by surgical procedures to stabilize the carpal joint. Open techniques include bone-ligament-bone transfers, tenodesis, partial fusions and carpectomies. Innovative procedures using wrist arthroscopy, offer minimally invasive fixation without full exposure of carpal bones; however, the success of the technique and its impact on the reduction on the range of carpal movement is as yet not well known. In this work, the performance of Corella tenodesis technique to repair the SL ligament is evaluated for a wrist type II by numerical methods. Human wrist can be classified based on the lunate morphology: type I for lunate that articulates with radius, scaphoid, capitate and triquetrum, and type II which has an extra surface to articulate with the hamate. A finite element model was constructed from CT-scan images, the model includes cortical and trabecular bones, articular cartilage and ligaments. Three scenarios were simulated representing healthy wrist, SL ligament sectioning and the Corella technique. The performance of the technique was assessed by measure the SL gap in dorsal and volar side as well as the SL angle to be compared to cadaveric studies. In intact position, the SL gap and the SL angle predicted by the numerical model is 2.8 mm and 44.8º, these values are consistent to the standard values reported in cadaveric experiments (2.0 ± 0.8 mm for SL gap and 45.8 ± 9.7 for SL angle). Virtual surgeries may help to understand and evaluate the performance of the techniques at clinical application

Repair of tendon injuries aims to restore length, mechanical strength and function. We hypothesise that Demineralised Cortical Bone (DCB) present in biological tendon environment will result in remodelling of the DCB into ligament tissue. A cadaveric study was carried out to optimize the technique. The distal 1cm of the patellar tendon was excised and DCB was used to bridge the defect. 4 models were examined, Model-1: one anchor, Model-2: 2 anchors, Model-3: 2 anchors with double looped off-loading thread, Model-4: 2 anchors with 3 threads off-loading loop. 6 mature sheep undergone surgical resection of the distal 1cm of the right patellar tendon. Repair was done using DCB with 2 anchors. Immediate mobilisation was allowed, animals were sacrificed at 12 weeks. Force plate assessments were done at weeks 3, 6, 9 and 12. Radiographs were taken and pQCT scan was done prior to histological analysis. In the cadaveric study, the median failure force for the 4 models; 250N, 290N, 767N and 934N respectively. In the animal study, none of the specimens showed evidence of ossification of the DCB. One animal failed to show satisfactory progress, X-rays showed patella alta, on specimen retrieval there was no damage to the DCB and sutures and no evidence of anchor pullout. Functional weight bearing was 79% at week12. Histological analysis proved remodelling of the collagen leading to ligamentisation of the DCB. Results prove that DCB can be used as biological tendon substitute, combined with the use of suture bone anchor early mobilisation can be achieved

Background. Ankle fractures are often associated with ligamentous injuries of the distal tibiofibular syndesmosis, the deltoid ligament and are predictive of ankle instability, early joint degeneration and long-term ankle dysfunction. Detection of ligamentous injuries and the need for treatment remain subject of ongoing debate. In the classic article of Boden it was made clear that injuries of the syndesmotic ligaments were of no importance in the absence of a deltoid ligament rupture. Even in the presence of a deltoid ligament rupture, the interosseous membrane withstood lateralization of the fibula in fractures up to 4.5mm above the ankle joint. Generally, syndesmotic ligamentous injuries are treated operatively by temporary fixation performed with positioning screws. But do syndesmotic injuries need to be treated operatively at all?. Methods. The purpose of this biomechanical cadaveric study was to investigate the relative movements of the tibia and fibula, under normal physiological conditions and after sequential sectioning of the syndesmotic ligaments. Ten fresh-frozen below-knee human cadaveric specimens were tested under normal physiological loading conditions. Axial loads of 50 Newton (N) and 700N were provided in an intact state and after sequential sectioning of the following ligaments: anterior-inferior tibiofibular (AITFL), posterior-inferior tibiofibular (PITFL), interosseous (IOL), and whole deltoid (DL). In each condition the specimens were tested in neutral position, 10 degrees of dorsiflexion, 30 degrees of plantar flexion, 10 degrees of inversion, 5 degrees of eversion, and externally rotated up to 10Nm torque. Finally, after sectioning of the deltoid ligament, we triangulated Boden's classic findings with modern instruments. We hypothesized that only after sectioning of the deltoid ligament; the lateralization of the talus will push the fibula away from the tibia. Results. During dorsiflexion and external rotation the ankle syndesmosis widened, and the fibula externally rotated after sequential sectioning of the syndesmotic ligaments. After the AITFL was sectioned the fibula starts rotating externally. However, the external rotation of the fibula significantly reduced when the external rotation torque was combined with axial loading up to 700N as compared to the external rotation torque alone. The most relative moments between the tibia and fibula were observed after the deltoid ligament was sectioned. Conclusion. Significant increases in movements of the fibula relative to the tibia occur when an external rotation torque is provided. However, axial pressure seemed to limit external rotation because of the bony congruence of the tibiotalar surface. The AITFL is necessary to prevent the fibula to rotate externally when the foot is rotating externally. The deltoid ligament is the main stabilizer of the ankle mortise

Background. Despite arthroscopy being the gold standard for long head of biceps pathology, the literature is seemingly lacking in any critical appraisal or validation to support its use. The aim of this study was to evaluate its appropriateness as a benchmark for diagnosis. The objectives were to evaluate whether the length of the tendon examined at arthroscopy allows visualisation of areas of predilection of pathology and also to determine the rates of missed diagnoses when compared to an open approach. Methods. A systematic review of cadaveric and clinical studies was performed. The search strategy was applied to Medline, PubMed and Google Scholar databases. All relevant articles were included. Critical appraisal of clinical studies was performed using a validated quality assessment scale. Results. Six articles were identified for inclusion in the review. This included both clinical and cadaveric studies. The overall population comprised 25 cadaveric specimens and 575 patients. Cadaveric studies showed that the use of a hook probe allowed arthroscopic visualisation of between 28% and 48% of the overall length of the LHB. In the clinical series the rate of missed diagnoses at arthroscopy when compared to open exploration ranged between 33% and 49%. Conclusions. The standard technique of pulling the LHB tendon into the joint at glenohumeral arthroscopy provides only limited excursion and does not allow visualisation of areas of predilection of pathology. This is confirmed by an extremely high rate of missed diagnoses when comparing arthroscopy to open exploration. It is important that clinicians recognise that a “normal” arthroscopic examination of the LHB tendon does not exclude pathology and that published literature reporting sensitivities and specificities for physical examination and imaging tests based on arthroscopy as a gold standard are invalid. Level of evidence. IIa – systematic review of cohort studies. Conflict of Interests. The authors confirm that they have no relevant financial disclosures or conflicts of interest. Ethical approval was not sought as this was a systematic review

Anatomical atlases document safe corridors for placement of wires when using fine-wire circular external fixation. The furthest posterolateral corridor described in the distal tibia is through the fibula. This limits the crossing angle and stability of the frame. In this paper we describe a new, safe Retro-Fibular Wire corridor, which provides greater crossing angles and increased stability. In a cadaver study, 20 formalin-treated legs were divided into two groups. Wires were inserted into the distal quarter of the tibia using two possible corridors and standard techniques of dissection identified the distance of the wires from neurovascular structures. In both groups the posterior tibial neurovascular bundle was avoided. In group A the peroneal artery was at risk. In group B this injury was avoided. Comparison of the groups showed a significant difference (p < 0.001). We recommend the Retro-Fibular wire technique whereby wires are inserted into the tibia mid-way between the posteromedial border of the fibula and the tendo Achillis, at 30° to 45° to the sagittal plane, and introduced from a posterolateral to an anteromedial position. Subsequently, when using this technique in 30 patients, we have had no neurovascular complications or problems relating to tethering of the peroneal tendons

Long-term regeneration of cartilage defects treated with tissue engineering constructs often fails because of insufficient integration with the host tissue. We hypothesize that construct integration will be improved when implants actively interact with and integrate into the subchondral bone. Growth and Differentiation Factor 5 (GDF-5) is known to support maturation of chondrocytes and to enhance chondrogenic differentiation and hypertrophy of mesenchymal stromal cells (MSC). Therefore, we investigated whether GDF-5 is capable to stimulate endochondral ossification of MSC in vitro and in vivo and would, thus, be a promising candidate for augmenting fibrin glue in order to support integration of tissue engineering constructs into the subchondral bone plate. To evaluate the adhesive strength of fibrin glue versus BioGlue. ®. , a commercially available glue used in vascular surgery, an ex vivo cadaver study was performed and adhesion strength was measured via pull-out testing. MSC were suspended in fibrin glue and cultivated in chondrogenic medium with and without 150 ng/mL GDF-5. After 4 weeks, the formed cartilage was evaluated and half of the constructs were implanted subcutaneously into immunodeficient mice. Endochondral ossification was evaluated after 2 and 4 weeks histologically and by microCT analysis. BioGlue. ®. and GDF-5-augmented fibrin glue were tested for 4 weeks in a minipig cartilage defect model to assess their orthotopic biocompatibility. Pull-out testing revealed sufficient adhesive strength of fibrin glue to fix polymeric CellCoTec constructs in 6 mm cartilage defects, however, BioGlue. ®. showed significantly higher adhesive power. In vitro chondrogenesis of MSC under GDF-5 treatment resulted in equal GAG deposition and COLIIa1 and ACAN gene expression compared to controls. Importantly, significantly increased ALP-activity under treatment with GDF-5 on day 28 indicated enhanced hypertrophic differentiation compared to controls. In vivo, MSC-fibrin constructs pre-cultured with GDF-5 developed a significantly higher bone volume on day 14 and 28 compared to controls. When pre-cultured with GDF-5 constructs showed furthermore a significantly higher bone compactness (bone surface/bone volume coefficient) than controls, and thus revealed a higher maturity of the formed bone at 2 weeks and 4 weeks. Orthotopic biocompatibility testing in minipigs showed good defect filling and no adverse reactions of the subchondral bone plate for defects treated with GDF-5-augmented fibrin glue. Defects treated with BioGlue. ®. , however, showed considerable subchondral bone lysis. Thus, BioGlue. ®. – despite its adhesive strength – should not be used for construct fixation in cartilage defects. GDF-5-augmented fibrin glue is considered promising, because of a combination of the adhesive strength of fibrin with an enhanced osteochondral activity of GDF-5 on MSC. Next step is to perform a large animal study to unravel whether GDF-5 stimulated endochondral ossification can improve scaffold integration in an orthotopic cartilage defect model