Effect of cyclic loading on the ultimate tensile strength of small metallic suture anchors used for attaching artificial tendons in rabbits.

Background ­: Suture anchor failures can lead to revision surgeries which are costly and burdensome for patients. The durability of musculoskeletal reconstructions is therefore partly affected by the design of the suture anchors. Purpose ­: The purpose of the study was to quantify the strength of different suture anchors whose sizes are suitable for attaching artificial Achilles and tibialis cranialis tendons in a rabbit model, as well as determine the effect of cyclic loading on the anchoring strength. Method ­: Four anchors (two with embedded eyelet and two with raised eyelet, n=5 per group) were tested with cyclical loading (1000 cycles and 4.5 mm/sec) and without cycling, to inform the failure loads and mode of failure of the suture anchors. An eyebolt screw with smooth eyelet was used as a control for the test groups. Results ­: All samples in all groups completed 1000 cycles and failed via suture breakage in both test conditions. All anchors had failure loads exceeding the peak Achilles tendon force in rabbits during hopping gait. The data analysis showed an effect of anchor type on the maximum tensile force at failure (F max ) in all suture categories but not an effect of loading condition. Also, the Anika anchor had a significantly less adverse effect on suture strength compared to Arthrex anchor (p=0.015), IMEX anchor (p=0.004) and Jorvet anchor (p<0.001). We observed a greater percentage of failure at the mid-section for the anchors with the raised eyelets compared to the anchors with embedded eyelets, which all failed at the knot. Conclusion ­: Anchors with embedded eyelets had clinically preferred mode of failure with less adverse effects on suture and, may be more reliable than anchors with raised eyelets for attaching artificial Achilles and tibialis cranialis tendons in rabbits.

Attaching artificial Achilles and tibialis cranialis tendons to bone using suture anchors in a rabbit model: assessment of outcomes.

Objective: The purpose of this study was to investigate the factors associated with outcomes of attaching artificial tendons to bone using suture anchors for replacement of biological tendons in rabbits. Study Design: Metal suture anchors with braided composite sutures of varying sizes (USP #1, #2, or #5) were used to secure artificial tendons replacing both the Achilles and tibialis cranialis tendons in 12 New Zealand White rabbits. Artificial tendons were implanted either at the time of (immediate replacement, n=8), or four weeks after (delayed replacement, n=4) resection of the biological tendon. Hindlimb radiographs of the rabbits were obtained immediately after surgery and approximately every other week until the study endpoint (16 weeks post-surgery). Results: All suture anchors used for the tibialis cranialis artificial tendons remained secure and did not fail during the study. The suture linkage between the Achilles artificial tendon and anchor failed in 9 of 12 rabbits. In all cases, the mode of failure was suture breakage distant from the knot. Based on radiographic analysis, the mean estimated failure timepoint was 5.3±2.3 weeks post-surgery, with a range of 2-10 weeks. Analysis of variance (ANOVA) tests revealed no significant effect of tendon implantation timing or suture size on either the timing or frequency of suture anchor failure. Conclusion: Based on the mode of failure, suture mechanical properties, and suture anchor design, we suspect that the cause of failure was wear of the suture against the edges of the eyelet in the suture anchor post, which reduced the suture strength below in vivo loads. Suture anchor designs differed for the tibialis cranialis and did not fail during the period of study. Future studies are needed to optimize suture anchor mechanical performance under different loading conditions and suture anchor design features.

Replacement of tibialis cranialis tendon with polyester, silicone-coated artificial tendon preserves biomechanical function in rabbits compared to tendon excision only.

BACKGROUND: Artificial tendons may be an effective alternative to autologous and allogenic tendon grafts for repairing critically sized tendon defects. The goal of this study was to quantify the in vivo hindlimb biomechanics (ground contact pressure and sagittal-plane motion) during hopping gait of rabbits having a critically sized tendon defect of the tibialis cranialis and either with or without repair using an artificial tendon. METHODS: In five rabbits, the tibialis cranialis tendon of the left hindlimb was surgically replaced with a polyester, silicone-coated artificial tendon (PET-SI); five operated control rabbits underwent complete surgical excision of the biological tibialis cranialis tendon in the left hindlimb with no replacement (TE). RESULTS: At 8 weeks post-surgery, peak vertical ground contact force in the left hindlimb was statistically significantly less compared to baseline for the TE group (p = 0.0215). Statistical parametric mapping (SPM) analysis showed that, compared to baseline, the knee was significantly more extended during stance at 2 weeks post-surgery and during the swing phase of stride at 2 and 8 weeks post-surgery for the TE group (p < 0.05). Also, the ankle was significantly more plantarflexed during swing at 2 and 8 weeks postoperative for the TE group (p < 0.05). In contrast, there were no significant differences in the SPM analysis among timepoints in the PET-SI group for the knee or ankle. CONCLUSIONS: Our findings suggest that the artificial tibialis cranialis tendon effectively replaced the biomechanical function of the native tendon. Future studies should investigate (1) effects of artificial tendons on other (e.g., neuromuscular) tissues and systems and (2) biomechanical outcomes when there is a delay between tendon injury and artificial tendon implantation.

Low-cost body-powered prosthesis for transfemoral amputation.

To allow an amputee resume healthy walking, a well-designed lower limb prosthesis is required. However, in many developing countries, the cost of high-tech and often imported prosthesis is out of the financial reach of many amputees. The objective of this study was to design and implement a mechanical, body-powered transfemoral prosthetic device to help transfemoral amputees regain functional ambulation. The materials used include socket adapter, acetone hardener, plaster of Paris bandages, perlite lining, and polyester resin. Using anthropometric measurements of a volunteer amputee, a user-friendly and ergonomic transfemoral prosthetic device was designed using AutoCAD rendering and fabricated using engineering methods such as casting and welding. The prosthetic limb consists of a polypropylene socket, a galvanised iron knee joint with a hinge and spring suspension system, and a perlite foot. An evaluation of the prosthetic limb after fabrication showed that it restores the ambulatory function of the amputee.

Biomechanics in Africa: current state and potential for growth.

The potential of biomechanics for improving human health and performance is well established in many parts of the world. However, across most of Africa, biomechanics remains relatively underdeveloped. The discussion around biomechanics in the continent has increased in recent times and young African scientists are pursuing career opportunities in biomechanics-related fields within Africa and in other parts of the world. New institutions and programmes that focus on biomechanics teaching and research are also starting up around the continent. The advent of the National Biomechanics Day event, formation of the first formal biomechanics society in South Africa, along with many collaborations with relevant stakeholder organizations around the world underpin the expansion of biomechanics in Africa. This article aims to summarize the current state and describe aspirations for the future of biomechanics in Africa.

Modified orthopedic traction system for cervical and lower limb rehabilitation.

BACKGROUND: Orthopedic tractions can be employed in the rehabilitation of patients suffering from problems affecting the spine, as well as the upper and lower extremities but the high costs of using tractions due to prolonged hospital stays is a major disadvantage particularly in low-income economies. OBJECTIVE: The objective of this study was to design and develop a two-way adjustable traction system that accommodates both cervical and lower limb rehabilitation and improves limb and neck positioning. METHOD: The production process involved the use of computer-aided design (CAD) as well as other manufacturing procedures like material selection, welding, and drilling. The system was tested for stability to be sure it does not fail under large loads. RESULT: A functional and easy-to-install two-way orthopedic traction system for both hospital and home use was developed, installed and tested. The dimensions and adjustability would ensure that it can be used for children and adults. CONCLUSION: This study describes a device that can be used in hospitals. When used at homes, it can reduce the cost of medical bills, and provide patients with the emotional/psychological benefits of being cared for in a familiar environment.

Advancing biomechanics in Africa through National Biomechanics Day outreach - The Nigerian experience.

National Biomechanics Day (NBD) can raise public understanding and awareness of the field of biomechanics, as well as boost the number and diversity of young people interested in entering the profession and pursuing a career in it, especially in regions like Nigeria and Africa. The circumstances leading up to Nigeria's first NBD are summarized in this paper. It is hoped that if this trend continues, it would draw a large number of young people into biomechanics and biomechanics-related careers.

Anthropometric perspective to classroom furniture ergonomics and the need for standards in Nigerian schools.

BACKGROUND: Classroom furniture designs have been implicated in musculoskeletal disorders among school age persons due to high level mismatches between the furniture dimensions and users' anthropometrics. OBJECTIVE: The objective of the study was to analyze classroom furniture ergonomics at selected primary, secondary and tertiary educational institutions in Nigeria and to understand if there are noticeable patterns in the match/mismatch. METHOD: Anthropometric measures relevant to furniture design were obtained from primary and secondary school children as well as from university undergraduates. The dimensions of classroom furniture available to the participants were also taken and an assessment of the suitability of the furniture was completed. RESULT: The ergonomic evaluation of the classroom furniture available to the study participants revealed enormous discrepancies between the furniture dimensions and the anthropometric measures of the users. In addition, a pattern was observed in the way the matches/mismatches occurred. The furniture dimensions that matched majority of the users tend to match across the three categories and those that did not match majority of the students, also followed the same pattern. CONCLUSION: The study presents remarkably high levels of mismatches between classroom furniture and users' anthropometrics and therefore calls for a review of the policies for classroom furniture design in Nigeria, if at all any policy exists.

Preventive and Restorative Responses of Broccoli Sprouts on Biomechanical Structures, Histomorphometric, and Gene Expression Levels of Degenerated Intervertebral Disc in Rabbit Model.

STUDY DESIGN: Symptomatic disk degeneration is characterized by early pathological changes in the morphological, biochemical, and biomechanical properties of the intervertebral disc (IVD). Several methods that can be used to resolve this condition are being researched. PURPOSE: The present study was designed to examine the preventive and restorative properties of broccoli sprouts extracts in an annular puncture rabbit model of IVD degeneration. OVERVIEW OF LITERATURE: IVD degeneration is closely associated with low back pain. A degenerated IVD is cytoarchitecturally characterized by a reduction in cell number, morphological changes in the disk tissue, and changes in the extracellular matrix contents. Methods, such as imaging and biochemical characterization, have been used for distinguishing between degenerated disk and non-degenerated disk. METHODS: Twenty New Zealand white rabbits (weighing approximately 2.0-3.5 kg) were divided into four groups (n=5). Group 1 received 50 mg/kg of normal saline solution orally for 4 weeks; group 2 received 50 mg/kg of normal saline solution immediately after puncture for 4 weeks; group 3 received 300 mg/kg of aqueous extract of broccoli sprouts orally immediately after puncture for 4 weeks; and group 4 received 300 mg/kg of aqueous extract of broccoli sprouts after 4 weeks of puncture for another 4 weeks. After the experiment, the disk height index (DHI), histomorphometry, and gene expression level were measured and analyzed. RESULTS: The photomicrograph showed that the histological features of the punctured-treated groups (groups 3 and 4) were more similar to those of the non-punctured group than those of the punctured non-treated group. There was a significant difference in the DHI and relative gene expression levels among the non-treated punctured groups compared with those of the non-punctured and punctured-treated groups, respectively. CONCLUSIONS: This study shows that the aqueous extract of broccoli sprouts exerts preventive and restorative effects in a rabbit model with disk degeneration.

Design and development of an ergonomic neonatal surgical table.

In many regions, neonatal surgical procedures are conducted on adult-sized tables because neonatal surgical tables are rare. The objective of this study was to design and develop an ergonomic neonatal surgical table to help neonatal and infant surgeons avoid musculoskeletal disorders and improve effectiveness with neonatal surgeries. AutoCAD design software was used for the design in addition to other production engineering procedures like material selection and acquisition, cutting, welding, and drilling. The design utilised the anthropometric measures of a target user population. The device consists of a table surface, a surface adjustment lever, a linear actuator, and the foot pedal for adjusting table height and was observed to be ergonomically appropriate for the surveyed demographic. The adjustability of the table height, which is an important feature of the design, is also expected to permit a wide range of users who may not have been part of the study. The result of this study has the potential of creating a safer work environment for surgeons who attend to neonates, as well as supporting future studies on the ergonomics of neonatal surgeries.