Effect of geometrical design variables on implantation configuration and fixation stiffness of titling bone anchors: A parametric finite element study.

The mechanical interaction of a tilting anchor and cancellous bones of various densities was simulated using finite element modeling. The model enjoyed a sophisticated representation of the bone, as an elasto-plastic material with large deformation capability. The anchor's tilting action during implantation phase, as well as its fixation stiffness during pull-out test, were predicted by the model and a parametric study was performed to investigate the effects of the anchor's distal width and corner fillet radius, on these measures. The model predictions were validated against the results of an experimental test on ovine humerus specimens. The model could reasonably reproduce the tilting action of the anchor during the implantation phase. Comparison of the model predictions with the experimental results revealed similar trends during both the implantation and the pull-out phases, but smaller displacement magnitudes (end points: 1.4 vs. 2.1 mm and 4.6 vs. 5.2 mm, respectively). The results of the parametric study indicated substantial increase in the fixation stiffness with increasing bone density. Reducing the distal width and increasing the fillet radius improved the anchor's implantation configuration and fixation stiffness in low-density bones. For high-density bone applications, however, a larger distal width was favored for improving the fixation stiffness.

Surgical treatment of a nonunion following clavicle osteotomy in a child with a history of Erb's palsy: A case report.

INTRODUCTION AND IMPORTANCE: Erb's palsy defined as muscle weakness and loss of motion caused by a nerve condition in the shoulder and arm. Children with Erb's palsy might underwent clavicle osteotomy as an appropriate surgical treatment method. However, few number of these patients who underwent clavicle osteotomy experienced nonunion and complained of shoulder deformity and pain. The aim of the present case report was to present new surgical treatment of a nonunion following clavicle osteotomy in a child affected by Erb's palsy. CASE PRESENTATION: A six years old boy with a history of Erb's palsy who underwent clavicle osteotomy at age of 6 months was referred to hospital. There was a nonunion following clavicle osteotomy. The patient had right shoulder deformity and complained of its-related pain. To correct a nonunion following clavicle osteotomy in this case, middle third fibula auto grafting and fixing it to the cite of clavicle nonunion by pins was used. After five months of follow-up, a clavicle nonunion and shoulder deformity was thoroughly corrected. CLINICAL DISCUSSION: As clavicle osteotomy, the most commonly surgical method for Erb's palsy, has been demonstrated to not work effectively and cause nonunion in some cases, a new surgical method for correcting clavicle nonunion other than repeated clavicle osteotomy is needed. In the present case report, fibula auto grafting and fixing it to the cite of clavicle nonunion by pins was applied and demonstrated remarkable improvement. CONCLUSION: Totally, use of fibula auto grafting and fixing it to the cite of clavicle nonunion by pins might be an effective surgical treatment for such cases.

An additively manufactured titanium tilting suture anchor: a biomechanical assessment on human and ovine bone specimens.

Introduction: A novel titanium tilting suture anchor was designed and fabricated using additive manufacturing. The anchor enjoyed a nonsymmetrical structure to facilitate its insertion procedure through a weight-induced tilt, a saw-teeth penetrating edge to provide a strong initial fixation into cancellous bones of various densities, and an appropriate surface texture to enhance the longterm fixation strength through bone ingrowth. Methods: Biomechanical tests were performed on 10 ovine and 10 human cadaveric humeri to examine the insertion procedure and assess the initial fixation strength of the anchor, in comparison with a standard screw-type anchor as control. Results: This study indicated a simple yet reliable insertion procedure for the tilting anchor. All anchors survived after 400 cycles of cyclic loadings and failed in the load-to-failure step. There were no significant differences between the displacements and fixation stiffnesses of the anchors in either group. The ultimate failure load was significantly smaller (p<0.05) for tilting anchors in ovine group (273.7 ± 129.72 N vs. 375.6 ± 106.36 N), but not different in human group (311.8 ± 82.55 N vs. 281.9 ± 88.35). Also, a larger number of tilting anchors were pulled out in ovine group (6 vs. 3) but a smaller number in human group (4 vs. 6). Conclusion: It was concluded that the biomechanical performance of the designed tilting anchor is comparable with that of the standard screw-type anchors.

Medical education during the COVID-19 pandemic: lessons for the orthopedic departments.

BACKGROUND: After the Coronavirus pandemic, many educational routines were stopped for the safety of medical staff. To achieve educational goals, we have implemented new policies in our hospitals. In this study, we aimed to evaluate the effect of such strategies. METHOD: This survey-based study uses questionnaires to assess newly implemented educational strategies. We surveyed 107 medical staff of the orthopedic department of Tehran University of Medical Sciences, including faculty members, residents, and students. The survey contained three series of questionnaires for these groups. RESULTS: The maximum satisfaction for all three groups was observed in the platform and facilities for using e-classes, and the cost- and time-saving capabilities (Respectively, faculty members (FM): 81.8%, residents (R): 95.2%, students/interns (S/I): 87.0%; FM: 90.9%, R: 88.1%, S/I: 81.5%). The new policies have been shown to reduce the stress level of most trainees, increase the quality of knowledge-based education, increase the opportunity for reexamining educational content, expand discussion and research opportunities, and improve work conditions. There was a broad acceptance of the virtual journal clubs and morning reports. However, there were discrepancies between residents and faculty members on issues such as the evaluation of trainees, the new educational curriculum, and flexible shift schedules. Our strategies failed to improve skill-based education and patient treatment status. Most participants indicated that e-learning should be used with face-to-face training post-pandemic (FM: 81.8%, R: 83.3%, S/I: 75.9%). CONCLUSION: Our efforts to optimize the educational system during this crisis have generally improved trainees' work conditions and educational experience. Most participants believed that e-learning and virtual methods should be used alongside traditional training as a complementary component after the pandemic.

New frontiers of tendon augmentation technology in tissue engineering and regenerative medicine: a concise literature review.

Tissue banking programs fail to meet the demand for human organs and tissues for transplantation into patients with congenital defects, injuries, chronic diseases, and end-stage organ failure. Tendons and ligaments are among the most frequently ruptured and/or worn-out body tissues owing to their frequent use, especially in athletes and the elderly population. Surgical repair has remained the mainstay management approach, regardless of scarring and adhesion formation during healing, which then compromises the gliding motion of the joint and reduces the quality of life for patients. Tissue engineering and regenerative medicine approaches, such as tendon augmentation, are promising as they may provide superior outcomes by inducing host-tissue ingrowth and tendon regeneration during degradation, thereby decreasing failure rates and morbidity. However, to date, tendon tissue engineering and regeneration research has been limited and lacks the much-needed human clinical evidence to translate most laboratory augmentation approaches to therapeutics. This narrative review summarizes the current treatment options for various tendon pathologies, future of tendon augmentation, cell therapy, gene therapy, 3D/4D bioprinting, scaffolding, and cell signals.

An unusual case of chest wall glomus tumor presenting with axillary pain: a case report and literature review.

BACKGROUND: Glomus tumor is an uncommon soft tissue tumor. However, as the tumor causes significant disability, its early diagnosis is essential. It involves subungual areas of fingers and toes in most cases, and its extra-digital involvement is rarely seen. To the best of the authors' knowledge, only a few chest wall involvement cases have been reported in the literature. CASE PRESENTATION: In this paper, we describe a 63-year-old patient with a chest wall glomus tumor presenting with axillary paroxysmal pain and limitation in his shoulder range of motion that had been missed for nearly 15 years. His symptoms were relieved immediately following surgical excision. CONCLUSION: Glomus tumors may involve any part of the human body. It is curable with surgical excision in most cases. Therefore, a correct early diagnosis has paramount importance. A high index of suspicion is needed for early diagnosis, especially when the tumor involves uncommon anatomic areas.

Mid- to long-term outcomes after reverse shoulder arthroplasty with latissimus dorsi and teres major transfer for irreparable posterosuperior rotator cuff tears.

AIM: The objective of this study was to describe the outcome of reverse shoulder arthroplasty (RSA) combined with modified L'Episcopo procedure at long-term follow-up (5 to 12 years). METHODS: A retrospective review of 17 RSAs (mean age 67.2 years) with the modified L'Episcopo procedure conducted between 2006 and 2016 was performed. All patients had a combined loss of active elevation and external rotation with an irreparable posterosuperior rotator cuff tear. Clinical assessment was performed with a minimum follow-up of five years (mean 97.3 months). Outcome measures included range of motion, subjective shoulder value (SSV), visual analogue scale (VAS), and Constant-Murley scores. RESULTS: All patients (16) demonstrated a significant improvement in all clinical and functional parameters. VAS pain scores improved from 6 ± 2.6 to 1 ± 1; SSV improved from 35 ± 14 to 72 ± 10; active forward elevation increased from 66° ± 34 to 125° ± 29; and active external rotation arm at the body increased from -11° ± 22 to 21° ±11 and in 90° of abduction from -10° ± 17 to 37° ± 24. The mean Constant score improved from 25 ± 11 to 59 ± 8. Active internal rotation did not significantly change (p = 0.332). CONCLUSION: At long-term follow-up, RSA combined with modified L'Episcopo procedure resulted in significant improvements in pain, range of motion, and functional scores for patients with shoulder pseudoparalysis and a lack of active external rotation caused by a massive posterosuperior cuff tear with a teres minor deficiency.

Epidemiology of Joint Dislocations and Ligamentous/Tendinous Injuries among 2,700 Patients: Five-year Trend of a Tertiary Center in Iran.

BACKGROUND: The epidemiology of traumatic dislocations and ligamentous/tendinous injuries is poorly understood. In this study, we aimed to evaluate the prevalence and distribution of various dislocations and ligamentous/tendinous injuries in a tertiary orthopedic hospital in Iran. METHODS: Musculoskeletal injuries in an academic tertiary health care center in Tehran February 2005 to October 2010 were recorded. The demographic details of patients with pure dislocations and ligamentous/tendinous injuries were extracted and the type and site of injuries were classified according to their specific age/gender groups. RESULTS: Among 18,890 admitted patients, 628 (3.3%) were diagnosed with dislocations and 2.081 (11%) with ligamentous/tendinous injuries. The total male/female ratio was 4.2:1 in patients with dislocations and 1.7:1 in patients with ligamentous/tendinous injuries. Shoulder was the most prevalent site of dislocation (50.6%), followed by fingers (10.1%), toes (7.6%), hip (7.3%), and elbow (6.5%). Ankle was the most common site of ligamentous/tendinous injury (53.5%), followed by midfoot (12.3%), knee (8.3%), hand (7%), and shoulder (5%). The mean ages of the patients in dislocations and ligamentous/tendinous injuries were 35.0±18.2 and 31.3± 15.1, respectively. There was no seasonal variation. CONCLUSION: Shoulder dislocation and ankle ligamentous injury are the most frequent injuries especially in younger population and have different distribution patterns in specific age and sex groups. Epidemiologic studies can help develop and evaluate the injury prevention strategies, resource allocation, and training priorities.

The effects of picric acid (2,4,6-trinitrophenol) and a bite-deterrent chemical (denatonium benzoate) on autotomy in rats after peripheral nerve lesion.

Denervation of the hind limb is a technique used to study peripheral nerve regeneration. Autotomy or autophagia is an undesirable response to denervation in such studies. Application of a commercially available lotion used to deter nail biting in humans reduced autotomy in rats after denervation but did not completely prevent it. In this study, this authors evaluated the application of picric acid to prevent autotomy in rats in peripheral nerve experiments. They carried out sciatic nerve transection in 41 adult female Wistar rats and then applied either bite-deterrent lotion (n = 26) or saturated picric acid solution (n = 15) topically to the affected hind limb immediately after surgery and every day for 1 month. Autotomy scores were lower for rats treated with picric acid than for rats treated with bite-deterrent lotion 1 week and 2 weeks after surgery but were not different between the two groups 4 weeks after surgery. The authors conclude that application of picric acid could be used as an alternative strategy to prevent autotomy in peripheral nerve studies.

Suture anchor fixation for scaphoid nonunions with small proximal fragments: report of 11 cases.

PURPOSE: To describe the use of 2 suture anchors as the fixation devices in the management of 11 patients with scaphoid proximal pole nonunions with small proximal fragments. METHODS: In a prospective study, 11 patients with proximal pole scaphoid nonunions (10 with small proximal fragments and 1 with an oblique nonunion line) were evaluated before surgery by standard wrist x-rays and functional wrist scores including a visual analog scale (VAS), Mayo wrist score, and Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH). The nonunion site was fixed with 2 suture anchors supplemented with autologous cancellous bone graft. Postoperative evaluations consisting of functional wrist scores and evaluation of radiological union were performed 9 months after surgery. RESULTS: At the end of the study, we observed union in 10 of the 11 patients. The QuickDASH and VAS scores showed significant improvement, and 10 patients had satisfactory Mayo scores. CONCLUSIONS: We propose the technique of suture anchor fixation for cases of proximal scaphoid nonunion in which secure internal fixation with common techniques is challenging because of the small size of the proximal fragment and the obliquity of the nonunion site. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Comparison of a new single-donor human fibrin adhesive with suture for posterior tibial nerve repair in rat: biomechanical resistance and functional analysis.

OBJECTIVE: The use of fibrin adhesives has a broad background in nerve repair. Currently the suboptimal physical properties of single- donor fibrin adhesives have restricted their usage. The present experiment studies the performance and physical characteristics of a modified fibrin glue prepared from single-donor human plasma in the repair of posterior tibial nerve of rat. METHODS: Forty Wistar rats were divided into 5 groups; in the control group, tibial nerve was completely transected and no treatment was done, while in the four experimental groups the nerve stumps were reconnected by one suture, three sutures, one suture with fibrin glue and fibrin glue alone respectively. During 8 weeks of follow-up, Tibial Function Index was measured weekly and adhesive strength, inflammation and scar formation were assessed at the end of the study. RESULTS: Nerve stumps dehiscence rate and adhesive strength were similar in all experimental groups and significantly differed from control group (P<0.05). By the end of the eighth follow-up week, functional recovery of one and three sutures groups were significantly higher than groups in which fibrin glue was used for repair (P<0.05). The amount of inflammation and scar tissue formation was similar among all groups. CONCLUSION: The study results show that the prepared single-donor fibrin adhesive has acceptable mechanical properties which could provide required adhesiveness and hold nerve stumps in the long term; yet, we acknowledge that more studies are needed to improve functional outcome of single donor fibrin adhesive repair.

Effect of bilateral median nerve excision on sciatic functional index in rat: an applicable animal model for autologous nerve grafting.

Autologous nerve graft is still the treatment of choice in peripheral nerve injury when end-to-end nerve repair is not possible. The sciatic nerve is the most widely used nerve in rat experimental studies. To assess the possibility of using the rat median nerve as a delayed animal autologous nerve graft model in nerve regeneration studies, the effect of median nerve excision on the sciatic functional index (SFI) was evaluated. Thirty rats were distributed into three equal groups: in the sciatic and median nerve excision (SMNE) group, 10 mm of the right sciatic nerve was excised and 5 mm of both median nerves were excised a week later; in the median nerve excision (MNE) group, 5 mm of both median nerves were excised (both sciatic nerves remained intact); in the control group, no intervention was performed. SFI was calculated before and after each intervention. There was no significant difference between mean SFI values calculated before and after median nerve excision in SMNE (-86.8 versus -88.4, P = 0.61) and MNE groups (-3.9 versus -3.3, P = 0.93). Therefore, it may be suggested that median nerve excision does not affect SFI measurements in intact and/or completely injured sciatic nerve, which may propose the median nerve as an autologous donor nerve graft model in rats.

Effect of decompression on complete spinal cord injury in rats.

To examine whether spinal cord decompression improves functional recovery and decreases lesion volumes in paraplegic (not paraparetic) rats and, if so, at what postoperative time it is most efficacious. The spinal cords of 63 female rats were compressed at T9 with Yasargil clips. Rats were assigned randomly to five different treatment groups of 3 s, 1 hr, 6 hr, 3 weeks, and 10 weeks. Locomotor behavior scoring was based on the Basso, Beattie, Bresnahan (BBB) Locomotor Rating Scale (Ohio State University, Columbus, OH) motor scores. Comparing five groups, the mean BBB was statistically higher in the 3-s group (P < 0.05). Comparison of progressive changes in BBB in each group revealed statistically meaningful improvement in the 3-s group, too. Spared surface area of spinal cord was 81.5 +/- 4.9% in 3-s group and 10.8 +/- 1.4% in the delayed groups of decompression (P = 0.039). Rats undergoing immediate decompression showed significantly better functional recovery and smaller lesion volumes.