Central Third Research Articles

Prediction of residual stress after cold rolling and coiling processes

The objective of this manuscript is to present an analytical-numerical methodology for predicting residual stresses after cold rolling of steel sheets, with or without coiling/uncoiling steps. This proposal considers the contribution of hardening after each pass, the increase in temperature arising from forming, with the consequent appearance of a thermal gradient between the center of the sheet and its surface, and the eventual plastic deformation/relief after coiling/uncoiling. Predicted results were compared to experimental data collected from a steel plant, as well as to results available in the literature. The coincidence of values was quite satisfactory, especially in the central third of the residual stress distribution curves. Experimental results from more diverse processes, with greater variation in the number of passes and strain rates, are desirable for definitive validation of the proposed prediction model.

British Cardiovascular Society survey of the provision and structure of cardiology multidisciplinary meetings in England

Multidisciplinary meetings (MDMs) are central to clinical decision-making in many areas of cardiology. This study assessed current provision and structure of cardiology MDMs in England in comparison with national guidelines.British Cardiovascular Society (BCS) members were surveyed regarding frequency, core attendees, and organisational aspects of cardiology MDMs for myocardial revascularisation, endocarditis, heart failure, aortic valve, mitral and tricuspid valve MDMs, whether local, regional or outside of the region. Access to electrophysiology (EP), inherited cardiac conditions, and adult congenital heart disease (ACHD) MDMs was also assessed.Survey responses were received from 64 hospitals across England, of which 40 (62%) were secondary care centres and 24 (38%) were tertiary care centres. All units had access to revascularisation MDMs, although 6% of them (all in secondary care centres) lacked any surgical representation. Heart failure MDMs were available in 94% of centres, but 7% reported no attendance by a cardiologist with specialist interest in heart failure, and 23% reported no attendance by a device specialist. 61% of centres had access to dedicated endocarditis MDMs; however, 11% were not attended by a microbiologist or infectious disease physician, and 22% were not attended by a surgeon. Aortic valve MDMs were available in 69% of centres, while mitral and tricuspid valve MDMs were available in 56% of centres. One quarter of centres reported no access to EP, and one third of centres reported no access to ICC or ACHD MDMs.Substantial improvements in provision and structure of cardiology MDMs in England are needed in order to meet national guidance.

Osseous cyst‐like lesions in an unusual location in the equine distal phalanx

SummaryOsseous cyst‐like lesions (OCLLs) of the distal phalanx commonly occur around midline. The dorsopalmar location can be challenging to identify radiographically; however, advanced imaging has shown they are typically located in the central and palmar thirds of the bone. This study reports unusually located OCLLs in the dorsal, axial aspect of the palmar processes of the distal phalanx in three horses, with communication with the distal interphalangeal (DIP) joint confirmed by contrast arthrography in two horses. All horses were lame and had lameness localised to the distal limb with diagnostic anaesthesia. A rounded radiolucency with a surrounding rim of increased opacity was identified in the dorsal aspect of a palmar process on radiographs, with the palmaroproximal–palmarodistal oblique (PaPrPaDiO) view being most useful. On magnetic resonance imaging (MRI), the lesions were seen as hyperintense structure on T2*, T2 FSE and STIR sequences; a thin rim of intermediate signal surrounding a low signal centre was seen on T1 images. A rim of low T1/T2 FSE signal was seen in the surrounding bone in all cases, consistent with sclerosis, and mildly increased STIR signal was present in the surrounding trabecular bone in two cases. Two horses underwent standing cone‐beam computed tomography (CT) examination of the affected foot, revealing a well‐defined hypoattenuating region within the dorsal, axial aspect of the palmar process of the distal phalanx, with surrounding rim of increased attenuation. Contrast arthrography was performed in two cases, one using radiographs and the other CT, and confirmed communication of the cystic lesion with the DIP joint in both cases. Although advanced imaging provided further information and allowed other possible causes of lameness to be identified, careful assessment of radiographs allowed these unusually located OCLLs to be identified in all cases.

A modified anterior cruciate ligament reconstruction with BTB autograft

Background. Central third of the patellar tendon is a well know graft for anterior cruciate ligament (ACL) reconstruction. However, it’s usage can be difficult in case of long patella tendon, which causes graft length discrepancy. The aim of this article is to evaluate the results of arthroscopic anterior cruciate ligament reconstruction with a help of original method of bone patella tendon bone graft preparation. Methods. 26 males operated for ACL tear have been included in the study. On the preoperative MRI scans the approximate length of ACL, tibial tunnel, patella tendon length and tibial bone plug length have been measured. The technique of tibial bone plug cut was optimized based on preoperative MRI assessment. Results. In all cases, MRI-based assessments were consistent with intraoperative measurements, hence there was possible to avoid graft length discrepancy. In a period of 12 weeks the average score on the step-and-holds test was 23.8±1.1, the single-leg squat test was 6.7±0.9 and the Y-balance test was 83.2±1.4. The average IKDS score was 64.9±5.7. Conclusion. The proposed method is appropriate for anterior cruciate ligament reconstruction in patients with long patella tendon.

Poster 241: Comparison of Short-Term Clinical Outcomes of Medial Patellofemoral Ligament Reconstruction Using Superficial Quadriceps Tendon and Using Hamstring Tendon in Patella Instability

Objectives: Medial patellofemoral ligament reconstruction (MPFLR) is widely acknowledged as a therapeutic approach for patella instability. While hamstring autografts are widely used in MPFLR, there are concerns regarding complications associated with the patella bone tunnel and fixation hardware, such as the endobutton. As an alternative, the superficial quadriceps (SQ) tendon has also been used presently. To date, few studies have evaluated the comparison of clinical outcomes between the grafts. The purpose of the present study is to compare the short-term clinical outcomes of MPFLR using superficial quadriceps tendon and using hamstring tendon. Methods: All patients who had undergone MPFLR for patella instability between 2017 and 2020 and were able to follow up for >2 years were retrospectively evaluated. For autograft of MPFLR, hamstring was inserted to the patellar bone tunnel formed at superomedial corner of the patella or through the whole patella (ST group), while the center third of the superficial layer of the quadriceps tendon graft was harvested and turned medially leaving its attachment to the patella intact (SQ group). Both grafts were fixed at Schottle’s point with an initial tension of 10-20 N and 30° of knee flexion. Preoperative assessment included the range of knee motion (ROM), and radiographic features such as tibial tubercle–trochlear groove (TT-TG) distance, patellar tilt, and sulcus angle. The Kujala score, Tegner activity score, Lysholm score, ROM, and patellar tilt were assessed at one year postoperatively. Failure was defined by a postoperative patellar dislocation, surgical revision for recurrent patellar instability or any complication. Paired t test and 2-way repeated measure analysis of variance followed by multiple comparison using the Bonferroni test was carried out for statistical analysis, and statistical differences were considered significant for values of p < 0.05. Results: Among 70 MPFL reconstructions, 65 patients (92.9%, 24 males and 41 females) were able to follow-up. The mean follow-up period was 3.1 years (2 to 5 years). There were 22 patients in the ST group and 43 patients in the SQ group. There was no difference in preoperative TT-TG distance (ST group: 14.1 mm ± 4.6 mm, SQ group: 16.2 mm ± 3.1 mm) and sulcus angle (ST group: 143.1° ± 12.4°, SQ group: 139.6° ± 8.9°). Postoperatively, there was no significant difference in Tegner activity score (ST group: 5.5 points ± 2.2 points, SQ group: 5.8 points ± 2.2 points), but the SQ group showed significantly high score in Lysholm score (ST group: 88.7 points ± 12.5 points, SQ group: 95.9 points ± 5.9 points; p < 0.01) and Kujala score (ST group: 91.8 points ± 4.1 points, SQ group: 94.9 points ± 5.1 points; p < 0.01). ROM improved postoperatively, but there was no significance between the 2 groups. The Tilting angle (preoperative; ST group: 24.8° ± 12.0°, SQ group: 20.2° ± 8.3°) improved significantly (postoperatively; ST group: 10.9° ± 4.8°, SQ group: 11.5 ± 4.5°) (p < 0.01). There were 3 failures (13.6%) in the ST group with 2 patellar fractures and 1 postoperative patellar dislocation requiring additional surgery. Conclusions: Both groups had good short-term results, but postoperative Lysholm score and Kujala score were higher in the SQ group. Postoperative improvement in tilting angle reveals that both grafts contribute to restoring MPFL function. However, concerning failures that occurred in the ST group, SQ autograft may be safe and considerable for MPFLR. [Figure: see text][Figure: see text]

Anatomy of the Naviculocuneiform Joint Complex.

The purpose of this study was to quantify the articular surfaces of the naviculocuneiform (NC) joint to help clinicians better understand common pathologies observed such as navicular stress fractures and arthrodesis nonunions. Twenty cadaver NC joints were dissected and the articular cartilage of the navicular, medial, middle, and lateral cuneiforms were quantified by calibrated digital imaging software. Statistical analysis included calculating the mean cartilage surface area dimensions of the distal navicular and proximal cuneiform bones. Length measurements on the navicular were obtained to estimate the geographic location of the interfacet ridges. Lastly, all facets of the articular surfaces were described in regard to the shape and location of cartilaginous or fibrous components. Results were compared using Student t tests. Navicular cartilage was present over 75.4% of the surface area of the proximal NC joint, compared with 72.6% of combined cuneiform cartilage distally. The mean height of the deepest (dorsal-plantar) measurement of navicular articular cartilage was 18 ± 3 mm. The mean heights of the distal medial, middle, and lateral cuneiform articular facets were 15 ± 1 mm, 17 ± 2 mm, and 15 ± 2 mm, respectively. There is significant variation among the articular surfaces of the NC joint. Additionally, the central third of the navicular was calculated to lie in the inter-facet ridge between the medial and middle articular facets of the navicular. Surgeons may consider this study data when performing joint preparation for NC arthrodesis as cartilage was present to a mean depth of 18 mm at the NC joint. Additionally, this study demonstrates that the central third of the navicular, where most navicular stress fractures occur, lies in the interfacet ridge between the medial and middle articular facets of the navicular.

Surgical reconstruction of medial eyelid defects using margin transposition, tarsal graft, and periosteal strip

ABSTRACT Purpose Surgical reconstruction of medially located lower eyelid defects can be challenging. The Hughes procedure, considered the standard for reconstruction in such cases, often falls short in terms of cosmetic outcomes. An alternative approach that combines medial transposition with a tarsal graft and periosteal strip has shown promise. Here, we aim to demonstrate the cosmetic advantages of medial transposition of a preserved temporal lower eyelid over other techniques. Method We conducted a retrospective study involving seven well-documented patients who underwent the procedure described below. The study was approved by the University’s Ethics Committee. Results All patients were followed up for one year. Lower eyelid defects spanned 50–80% of their total length, situated in the central third of the eyelid or the central to medial portion. Postoperative complications were minimal, with all patients exhibiting good cosmetic, functional, and anatomical outcomes at follow-up. Conclusion The absence of eyelashes is well tolerated if it is lateral, but when the defect is medial, medial transposition could be a good alternative to the familiar Hughes surgical intervention.

The impact of high volumes of COVID-related lung transplant on waitlist mortality for non-COVID candidates in the United States.

Some patients with coronavirus disease 19 (COVID) develop serious, irreversible lung disease, including acute respiratory distress syndrome or pulmonary fibrosis. For select candidates, lung transplant is the only option to improve quality and length of life. Because of the severity of end-stage COVID-related lung disease, these candidates receive high allocation priority in the United States, including higher priority than many patients without COVID-related lung disease. This study assessed whether transplant centers with a large volume of COVID-related lung transplants experienced an increase in waitlist mortality for non-COVID transplant candidates. Nineteen centers were included as high-volume programs, defined as being in the top third of centers who transplanted COVID patients. Of the 2867 non-COVID patients waitlisted at these centers, there was no significant difference in waitlist mortalities of non-COVID transplant candidates between the pre-COVID transplant era (January 2018-February 2020) and during the period of high COVID transplant volume (March 2020-October 2022) (subhazard ratio: .92 [95% CI=.81-1.05], p=.22). Among high volume centers, the decision to transplant and to prioritize patients with COVID-related lung disease did not significantly impact the waitlist mortality of other candidates.

Perfusion magnetic resonance imaging correlates with the duration of stages and lateral pillar class in Legg-Calvé-Perthes disease

BackgroundLegg-Calvé-Perthes disease (LCPD) progresses through 4 stages characterized by unique radiographic features, and stage duration is recognized as an important prognostic factor. Newer perfusion magnetic resonance imaging (pMRI) allows for the evaluation of vascularity early in the disease process. This study aims to describe the relationship between global and regional perfusion patterns on early pMRI and the duration of Waldenström stages. A secondary aim was to verify the relationship between hypoperfusion and subsequent lateral pillar class. MethodsThrough a prospectively collected multicenter international cohort, patients with early LCPD (Waldenström Stage I) and pMRI were followed with serial radiographs at 3-month intervals for a minimum of 2 years. Epiphyseal hypoperfusion was quantified by HipVasc Software for the entire epiphysis and regional thirds of the femoral head. Waldenström stages and lateral pillar class were determined by mode assessments from 3 pediatric orthopedic surgeons. Duration of the stage was defined as the interval between the first radiograph demonstrating features of stage IIa and stage IIIa for fragmentation and between IIIa and IV for reossification. ResultsOne-hundred and seven patients (88.8% male, median age 8.0 years) met the study criteria. The average global hypoperfusion was 73.7%. Poorer global perfusion was predictive of a longer duration of fragmentation (rho = 0.34, P < .001) and of reossification (rho = 0.38, P = .003). The average regional hypoperfusion of the medial, central, and lateral third of the femoral head was 65.3%, 83.7%, and 61.3% respectively, and was similarly related to the duration of fragmentation (rho = 0.26, 0.24, and 0.31, respectively) and of reossification (rho = 0.31, 0.43, and 0.39, respectively) (P < .05 for all). Similar to previous studies, we found a significant positive association between hypoperfusion in the lateral third of the femoral head and lateral pillar class (P = .037). ConclusionsThe degree of both global and regional hypoperfusion correlated with the duration of fragmentation and reossification stages in LCPD. Lateral epiphyseal hypoperfusion is predictive of lateral pillar class. Taken together, the information provided by perfusion magnetic resonance imaging can provide crucial prognostic information for children with LCPD. Key Concepts1.Amount of hypoperfusion both globally and regionally on perfusion MRI correlates with the duration of fragmentation and reossification stages in LCPD.2.Lateral epiphyseal hypoperfusion correlates with lateral pillar class.3.Perfusion information offered by contrast MRI can offer crucial prognostic information in children with LCP. Level of EvidenceII Prognostic Study

Chronic Achilles Tendon Avulsion Repair: Central Third Fascia Slide Technique with Flexor Hallucis Longus Transfer.

Chronic Achilles Tendon Avulsion Repair: Central Third Fascia Slide Technique with Flexor Hallucis Longus Transfer.

Harvesting the Quadriceps Tendon With a Minimally Invasive Approach

Background: This article describes a standardized, minimally invasive approach for harvesting the quadriceps tendon through a 2 to 3 cm transverse skin incision, presenting it as a viable option. Indications: This procedure is indicated for patients undergoing anterior cruciate ligament (ACL), posterior cruciate ligament, medial collateral ligament, or lateral collateral ligament reconstruction surgery using soft tissue quadriceps grafts. Technique Description: A transverse incision is made on the anterior face of the knee, followed by a longitudinal incision of the central third of the rectus femoris. We perform the distal detachment of the patella of the same tendon. Then, the tendon is extracted using a closed stripper. The graft is prepared and folded on itself, resulting in a double graft. Results: Twenty patients, 16 male and 4 female with complete rupture of ACL, were submitted to an ACL reconstruction using the quadriceps soft tissue graft with minimally invasive harvesting technique. The results were satisfactory for all patients. All patients showed good evolution in the immediate and late postoperative period, with no cases of joint stiffness, wound dehiscence, and no infections. Discussion/Conclusion: We can conclude that harvesting the quadriceps tendon with a minimally invasive approach is a valid and reliable option for the treatment of ligament tears of the knee. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form.

Assessment and Validation of Anterior Humeral Line for Diagnosing Supracondylar Humerus Fractures in the Pediatric Population.

Pediatric supracondylar humerus fractures are commonly evaluated using the anterior humeral line (AHL) on a lateral radiograph. Rotational variations in radiographic projection are common due to child discomfort and could lead to changes in management based on where the AHL intersects the capitellum. The purpose of this study was to establish whether rotational variations in elbow rotation leads to significant changes in AHL position and whether drawing the AHL based on the distal humerus versus shaft is more tolerant to rotation. Fifty children with nonoperative supracondylar humerus fractures were identified with sub optimally positioned injury and well positioned follow-up lateral radiographs. The proportion of the bone anterior to the intersection of the AHL and the capitellum was measured using the humeral shaft versus distal humerus to guide position of the AHL. This process was repeated on ten pediatric humerus dry cadaveric specimens which were imaged in 5-degree rotational increments along the axis of the humeral shaft from -20 to +20 degrees. AHL position correlated poorly when measured on rotated lateral radiographs of clinical patients versus non-rotated lateral radiographs when using the distal humerus as a guide (intraclass correlation coefficient 0.14), compared with when using the humeral shaft as a guide (intraclass correlation coefficient 0.81). When assessing the pediatric humerus dry cadavers between the 2 techniques, there was greater statistically significant variation in rotated positions compared with the neutral position in the distal humerus AHL measurement approach compared with the humeral shaft AHL measurement approach, with the mean AHL within the central third of the capitellum for more rotational positions when using the shaft compared with the distal humerus. With rotated lateral elbow radiographs in supracondylar humerus fractures, utilizing the humeral shaft provides more consistent AHL measurements than utilizing the distal humerus, and thus drawing the line starting at the shaft of the humerus is recommended for surgical decision making.

Bone-Patellar Tendon-Bone Allograft Preparation Technique for Anterior Cruciate Ligament Reconstruction

Background: Allograft anterior cruciate ligament (ACL) reconstruction, while it may have a higher failure rate in younger and more active populations, continues to serve as a viable graft option for the appropriately indicated patient. Efficient bone-patellar tendon-bone (BTB) allograft preparation is beneficial to reduce operating time and ensure optimal reconstruction with bony fixation. Indications: ACL reconstruction with BTB allograft is indicated for skeletally mature and older patients, patients who are less active and have fewer physical demands, patients who have had previously harvested autograft, circumstances where an autograft harvest is inadequate, patients with multiligament knee injuries, and patients who prefer allograft use. Technique Description: The central third of the BTB allograft is harvested, aiming for a graft diameter of 10 mm along the tendon. The tibial bone plug is first cut to a length of 25 to 30 mm and width of 10 mm with the saw at a 70° angle to the bone. The patellar bone plug is cut to a length of 25 mm and width of 10 mm with the saw at a 45° angle to the bone. The bone plugs are mobilized, and soft tissue is dissected to free the graft. The graft is trimmed until it fits through a 10-mm sizer on each side. A single hole is created with a k-wire in the patellar bone plug, and a #5 Ethibond suture is passed. On the tibial bone plug, 2 holes are made perpendicular to one another, and a #2 Fiberwire suture is passed through each of these holes. These sutures allow for facilitated graft passage and tensioning. Once the graft is affixed with interference screws, the graft is arthroscopically evaluated throughout range of motion. Results: ACL reconstruction with BTB allograft provides high success rates in appropriately selected patients. Data demonstrate more optimal mechanical properties by harvesting the central third of the allograft tendon in younger donors. Non-irradiated and less chemically processed grafts are also preferred to optimize biomechanical properties. Discussion/Conclusion: Bone-patellar tendon-bone allograft with 2 bone plugs offers a reliable alternative to other allografts or autografts. Preparing the allograft in a fashion similar to an autograft harvest may increase familiarity with techniques and facilitate surgical efficiency and graft passage. Patient Consent Disclosure Statement: The author(s) attests that consent has been obtained from any patient(s) appearing in this publication. If the individual may be identifiable, the author(s) has included a statement of release or other written form of approval from the patient(s) with this submission for publication.

Poster 105: Rotator cuff healing using demineralised bone fibers in ovine infraspinatus tendon models

Objectives: Rotator cuff tears are a common cause of shoulder pain and functional deficits. Although surgical repair is often able to restore function and resolve pain, high rates of postoperative structural failures have been reported. To improve the outcomes and reduce re-tear rates biologic tissue scaffolds have been used to augment and reinforce the primary tendon repair by providing mechanical support of the initial repair and ideally improving the rate and/or quality of biological healing at the tendon-bone interface. Demineralised bone fibers (DBF) are bone collagen and can be formed into a patch providing a scaffold and inductive bone morphogenetic proteins known to facilitate healing. This study evaluated the in vivo response of human DBF Patches (hDBF-P) as an onlay over the infraspinatus tendon (IST) and at the tendon-bone interface in an ovine model. Methods: The hDBF-P was characterised using stereozoom (Figure 1A) and environment electron microscopy (Figure 1B). The osteoinductivity (OI) was evaluated in the standard nude rat intramuscular implantation (IM) model at 28 days using mCT and paraffin histology. A bilateral model of an onlay or an enthesis repair was performed in 12 adult wethers following ethical approval. Four groups were evaluated at 6 and 12 weeks (n=3 per time point): Onlay control and hDBF treated; Enthesis repair control and hDBF treated. The onlay model simulated a tendon injury by 4 longitudinal slits along the IST and lateral drill holes in the proximal humerus in the onlay control group [1]. In the onlay treated group the hDBF-P was hydrated in saline and secured to the IST with interrupted 2-0 non-resorbable sutures (Figure 2A). On contralateral side, the central third of the IST was sharply dissected, the footprint burred, and 2 medial row anchors inserted. The sutures were passed through the IST in the enthesis repair control group. In the enthesis repair treatment group, the sutures were passed through the hDBF-P which was placed at the tendon bone interface followed by sutures through the IST. Two lateral push lock anchors were used for a suture bridge (Figure 2B) in the control and treated groups. Endpoints included clinical recovery, macroscopic dissection, 3T MRI, radiographs, mCT and paraffin histology processing, H&amp;E staining, and light microscopic evaluations to assess local cell and tissue responses and healing. Results: OI was confirmed on IM implantation in nude rats. The sheep recovered uneventfully with no adverse events macroscopically or radiographically. MRI in the onlay control group revealed little response and no increase in tendon thickness which was confirmed histologically. In contrast the onlay hDBF-P treated demonstrated increased tendon thickness and hDBF resorption with time. Histology showed some initial inflammatory cells that decrease with time in the onlay group. MRI in the hDBF-P treated enthesis group supported increased activity at the bone interface at 6 and 12 weeks compared to controls. Histology at the interface with hDBF-P showed evidence of new bone formation at 6 weeks that matured with time support enthesis reformation. Conclusions: hDBF-P is a collagen graft composed of demineralized bone fibers that have osteoconductive and osteoinductive potential. When formed into a patch, this implant provides a scaffold that can participate with the local biology. hDBF-P used as on-lay in a tendon injury model increased tendon thickness. hDBF-P when used at the interface between the tendon and bone facilitated enthesis reformation through its conductive and inductive potential as well as scaffold architecture. DBF patches represent an exciting allograft implant with the potential to address the clinical problems in rotator cuff surgery. Literature cited Van Kampen, C., et al. (2013). Tissue-engineered augmentation of a rotator cuff tendon using a reconstituted collagen scaffold: a histological evaluation in sheep. Muscles, ligaments and tendons journal, 3(3), p.229.

Poster 237: Menisco-Tibial Ligament Complex Anatomy and Biomechanics – Implications for Meniscus Repairs, Ramp Lesions and Transplants

Poster 237: Menisco-Tibial Ligament Complex Anatomy and Biomechanics – Implications for Meniscus Repairs, Ramp Lesions and Transplants

Research Note: Isolation, speciation, and anticoccidial sensitivity of Eimeria spp. recovered from wild turkey feces in the United States

Between 2018 and 2020, over 100 wild turkey fecal samples were collected from the Eastern and Central thirds of the United States, where commercial turkey production is uncommon. We hypothesized that anticoccidial-sensitive Eimeria spp. would be present in wild turkey fecal samples. Samples containing Eimeria spp. oocysts were amplified in vivo. If propagation was successful, the samples were PCR-speciated and subjected to anticoccidial sensitivity testing (AST) for key members of both ionophore and chemical categories of anticoccidial drugs. The purpose of this study was to isolate Eimeria spp. relevant to commercial turkey production that possessed sensitivity to monensin, zoalene, and amprolium. Future research would evaluate the efficacy of wild turkey Eimeria spp. as vaccine candidates for reducing coccidiosis in commercial turkey flocks utilizing single oocyst-derived stocks obtained in the present study.

Within-group spatial position in Saiga tatarica (Bovidae) in the Stepnoi State Nature Sanctuary, Astrakhan Region, Russia

In group-living animals, the social structure and organisation play a significant role in survival and reproduction. Understanding the social aspects of animal lives in the wild may be crucially important for effective conservation of threatened species. The fitness costs and benefits of living in a group are related to particular spatial positions individuals take within their groups. Age and sex of the individual is a major factor determining intra-group spatial position. In the present study, we investigated the within-group spatial positioning of individuals in the Critically Endangered Saiga tatarica (hereinafter – saiga). In saigas living under natural predation pressure in the Stepnoi State Nature Sanctuary (Astrakhan Region, Russia), we investigated the sex-age category of the first individual in the group, the inter-individual distance in the front individuals and the individuals following them, and the distribution of individuals of each sex-age category between various parts of the group. Three (summer) or four (autumn) sex-age categories of the individuals in the moving groups were recognised by direct observations in the field. In summer, adult females, accompanied by their calves, were the very first individuals in most saiga groups observed. This result agrees with the previous notion that experienced females often lead the saiga groups. However, further investigation is needed to confirm whether adult females do indeed take the role of a leader during long-distance group movements. In line with the results on other mammals, the majority of adult females moved in the central third of the group. Spatial preferences of adult females seem to be based on the risk minimisation as the central positions are likely the safest in the group. In autumn, juvenile males were moving first in the majority of the investigated groups probably because they were the most active and fast-moving sex-age category during this season. In addition, juvenile males and females were significantly more often observed in the first third of the group than in the central and the rear thirds. We suggest that despite the fact that the front edge of the group could be the most dangerous spatial position, foraging benefits may outweigh the increased risk for juvenile saigas. In contrast to some other mammals, adult males did not tend to move at the front edge and were equally often observed in the front, central and rear parts of saiga groups. Finally, our results showed that saigas closer to the front edge of the group maintained shorter inter-individual distances than the individuals positioned behind them. The tighter spacing could be used by front individuals to compensate for the increased risks associated with their within-group spatial position.

Impact of elevated serum advanced glycation end products and exercise on intact and injured murine tendons

ABSTRACT Overview: Delayed tendon healing is a significant clinical challenge for those with diabetes. We explored the role of advanced glycation end-products (AGEs), a protein modification present at elevated levels in serum of individuals with diabetes, on injured and intact tendons using a mouse model. Cell proliferation following tissue injury is a vital component of healing. Based on our previous work demonstrating that AGEs limit cell proliferation, we proposed that AGEs are responsible for the delayed healing process commonly observed in diabetic patients. Further, in pursuit of interventional strategies, we suggested that moderate treadmill exercise may support a healing environment in the presence of AGEs as exercise has been shown to stimulate cell proliferation in tendon tissue. Materials and Methods: Mice began receiving daily intraperitoneal injections of bovine serum albumin (BSA)-Control or AGE-BSA injections (200μg/ml) at 16-weeks of age. A tendon injury was created in the central third of both patellar tendons. Animals assigned to an exercise group began a moderate treadmill protocol one week following injury. The intact Achilles tendon and soleus muscle were also evaluated to assess the effect of BSA and AGE-BSA on un-injured muscle and tendon. Results: We demonstrate that our injection dosing and schedule lead to an increase in serum AGEs. Our findings imply that AGEs indeed modulate gene expression following a patellar tendon injury and have modest effects on gene expression in intact muscle and tendon. Conclusions: While additional biomechanical analysis is warranted, these data suggest that elevated serum AGEs in persons with diabetes may impact tendon health.

Chronic Achilles Tendon Repair: Minimally Invasive Turn-Down Technique with Flexor Hallucis Longus Tendon Transfer

Category: Sports; Ankle; Trauma Introduction/Purpose: Chronic achilles tendon injuries present several technical considerations. A reported 20-25% of acute ruptures may be missed and lead to late diagnosis. A commonly faced problem with chronic ruptures is the amount of tendon retraction that occurs, leading to the inability to perform a direct end-to-end repair. Previous studies have demonstrated that central turndown lengthening with addition of flexor hallucis longus (FHL) augmentation can be performed with good results, although it has been associated with post-surgical wound complications and infection. The following description is a turndown technique with FHL tendon transfer augmentation for chronic achilles rupture that allows increased fixation with a tendon to bone construct, accomplished with a minimally invasive approach. Methods: Dissection is made down to the Achilles rupture site. Scar tissue is debrided down to two stable ends. The residual gap is then measured and 2cm is added. This distance is then used to make a proximal incision. Dissection is performed to gastrocnemius tendinous raphe. The central third of this segment is incised perpendicularly. A quadriceps tendon harvester (Arthrex, Naples, FL) is utilized to cut in an antegrade fashion down the tendon portion percutaneously, leaving a 1-1.5cm of tendon spared distally. The tendon is pulled under and through the distal incision. A percutaneous achilles repair system (PARS, Arthrex, Naples, FL) Jig is used to span proximal tendon. FHL tendon transfer is then completed in usual fashion. Suture tails from proximal tendon are then passed through the distal end. Tension is pulled through the sutures, approximating repair. The suture is loaded onto anchors and secured into the calcaneus under tension. Results: Favorable outcomes have been observed following the 2 patients that have had chronic achilles repair with utilization of this minimally invasive turn-down technique with FHL transfer. At a follow up of at least 6 months, no patient has demonstrated wound dehiscence or breakdown. There have been no reports of re-rupture. All patients have been satisfied with the procedure and their level of returned function. Conclusion: Our method of repair with combination of central turndown procedure and FHL tendon transfer provides a suitable option for improved functional outcomes in the treatment of chronic achilles ruptures while providing a minimally invasive approach and avoiding the need for allograft tissue. By using the quadricep tendon harvester in a subcutaneous fashion, incision length can be reduced by nearly 50%. This technique can be performed with existing technologies and is readily reproducible. Using the tendon to bone fixation along with intra-tendinous shuttling, allows for excellent fixation strength, a knotless construct, and almost complete intra-substance suture placement.

Evolution of the patellar tendon size after Bone-Patelar tendon-Bone ACL reconstruction

Bone-patellar tendon-bone (BPTB) autograft is the main treatment choice on complete anterior cruciate ligament (ACL) ruptures. However, high donor-site morbidity has been related to this procedure. A better understanding of the donor-site healing process could help us to decrease donor-site problems. The aim of this study is to describe the evolution of the patellar tendon size during the first year after BPTB procedure. 42 consecutive patients underwent ACL reconstruction using BPTB technique in our facilities. We measured the tendon length, width and thickness through musculoskeletal ultrasound before and at 1, 2, 4, 6, 9 and 12 months after the operation. Tendon measurements from the contralateral unaffected tendon were used as a control group. We compared the values between injured and uninjured legs and between pre-op and post-op values. Tendon length decreased significantly in both legs, without any difference between legs at 12 months post-op. Tendon width and thickness of the unaffected limbs showed a tendency to stabilization, while the injured limb showed a significant increase in both values during the first 1-2 months. At 12-months post-op, patellar tendon of the injured limb was significantly wider and thicker than the unaffected contralateral limb. Harvesting the central third of the patellar tendon during the BPTB procedure after an ACL injury leads to significant changes in the patellar tendon that can last for up to 12 months after the surgery. Further research must focus on the translation of these findings into clinical signs with longest follow-up periods.