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In materials science, dislocations are irregularities within the crystal structure or atomic scale of engineering materials, such as metals, semi-conductors, polymers, and composites.Discussing this specific aspect of materials science and engineering, Introduction to Dislocations is a key resource for students.

BACKGROUND: This study aimed to compare the medium- to long-term results of elbow collateral ligament repairs performed with suture anchors. METHODS: Patients undergoing surgery for elbow collateral ligament repairs between 2011 and 2023 were retrospectively analyzed. We included patients who had undergone surgery for complex elbow dislocations. Patients were excluded from the study if they had a previous infection, a fracture, an operation on the same elbow, a stiff elbow, or a follow-up period of less than 1 year. For the functional evaluation, the range of motion (ROM) and the Mayo Elbow Performance Score (MEPS) were used for the postoperative functional assessments. The radiological evaluation used varus and valgus stress radiographs of healthy and operated extremities taken while applying an 80 N force with a digital dynamometer. RESULTS: Thirty-five patients (24 male and 11 female) were included in the study. Eighteen patients had isolated lateral collateral ligament (LCL) injuries, nine patients had isolated medial collateral ligament (MCL) injuries, and eight patients had LCL and MCL injuries. The mean age was 32 (18-68) years, and the follow-up period was 104.8 (32-147) months. The mean value of the MEPS was 92.1 [+ or -] 10.3; 22 patients had excellent, 11 patients had good, and only two patients had fair results. Patients with isolated LCL and MCL repairs achieved better flexion motion than patients with combined ligament repairs (142.5[degrees] and 141.7[degrees] vs. 138.6[degrees]). When comparing operated and healthy extremities, radiocapitellar joint distance (RCJD) was found to increase by 0.8 [+ or -] 0.5 mm, and ulnotrochlear joint distance (UTJD) was found to increase by 1.18 [+ or -] 0.5 mm, but these changes were not statistically significant. CONCLUSION: The results of this study suggest that the use of suture anchors in elbow collateral ligament injuries is a valid solution for treatment and prevention of instability in patients with isolated or combined repairs. Keywords: Collateral ligament; elbow dislocation, repair; stability. AMAC: Bu calismanin amaci, sutur capa kullanilarak yapilan dirsek kollateral bag tamirlerinin orta ve uzun vadeli sonuclarini karsilastirmaktir. GEREC VE YONTEM: 2011-2023 yillari arasinda dirsek kollateral bag onarimi yapilan hastalar retrospektif olarak analiz edildi. Kompleks dirsek cikiklari nedeniyle ameliyat edilen hastalar calismaya dahil edildi. Daha once ayni dirsekten enfeksiyon geciren, ayni dirsekten kirik ve ameliyat gecirme oykusu olan veya sert dirsek tanisi olan ve 1 yildan daha kisa takip suresi olan hastalar calismaya dahil edilmedi. Fonksiyonel degerlendirme icin eklem hareket acikligi (EHA) ve Mayo Elbow Performance Score (MEPS) kullanildi. Radyolojik degerlendirmede saglam ve ameliyat edilen ekstremitelere dijital dinamometre ile 80 N kuvvet uygulanirken cekilen varus ve valgus stres radyografileri kullanildi. BULGULAR: Calismaya 35 hasta (24 erkek ve 11 kadin) dahil edildi. On sekiz hastada izole lateral kollateral ligament (LKL) yaralanmalari, dokuz hastada izole medial kollateral ligament (MKL) yaralanmalari ve sekiz hastada LKL ve MKL yaralanmalari vardi. Ortalama yas 32 (18-68) yildi ve takip suresi 104.8 (32-147) aydi. Hastalarimizin ortalama MEPS degeri 92.1 [+ or -] 10.3 idi; 22 hastada mukemmel, 11 hastada iyi ve sadece iki hastada orta sonuc vardi. Izole LKL ve MKL onarimli hastalar, kombine bag onarimli hastalara gore daha iyi fleksiyon hareketi elde ettiler (142.5[degrees] ve 141.7[degrees]'ye karsi 138.6[degrees]). Ameliyat edilen ve saglam ekstremiteler karsilastirildiginda ameliyat edilen tarafta radyokapitellar eklem mesafesinin (RKEM) 0.8 [+ or -] 0.5 mm, ulnotroklear eklem mesafesinin (UTEM) ise 1.18 [+ or -] 0.5 mm arttigi bulundu, ancak bu degisiklikler istatistiksel olarak anlamli degildi. SONUC: Bu calismanin sonuclari, dirsek kollateral bag yaralanmalarinda dikisli capa kullanilarak yapilan izole veya kombine bag tamirlerinin instabilitenin tedavisi ve onlenmesi icin gecerli bir cozum oldugunu gostermektedir. Anahtar sozcukler: Dirsek cikigi; kollateral bag; stabilite; onarim.

Background Congenital dislocation of the knee is characterised by excessive knee extension or dislocation and anterior subluxation of the proximal tibia, and this disease can occur independently or coexist with different systemic syndromes. Nevertheless, significant controversy surrounds treating this disease when combined with hip dislocation. This paper presents a case of a 4-month-old patient diagnosed with bilateral hip dislocation combined with this disease. The study discusses the pathophysiology, diagnosis, and treatment methods and reviews relevant literature. Case presentation We reported a case of a 4-month-old female infant with congenital dislocation of the right knee joint, which presented as flexion deformity since birth. Due to limitations in local medical conditions, she did not receive proper and effective diagnosis and treatment. Although the flexion deformity of her right knee joint partially improved without treatment, it did not fully recover to normal. When she was 4 months old, she came to our hospital for consultation, and we found that she also had congenital dislocation of both hip joints and atrial septal defect. We performed staged treatment for her, with the first stage involving surgical intervention and plaster orthosis for her congenital dislocation of the right knee joint, and the second stage involving closed reduction and plaster fixation orthosis for her congenital hip joint dislocation. Currently, the overall treatment outcome is satisfactory, and she is still under follow-up observation. Conclusions Early initiation of treatment is generally advised, as nonsurgical methods prove satisfactory for mild cases. However, surgical intervention should be considered in cases with severe stiffness, unresponsive outcomes to conservative treatment, persistent deformities, or diagnoses and treatments occurring beyond the first month after birth.

Purpose Congenital dislocation of the knee and hip is a rare congenital disorder. The specific aim of the study was to evaluate the clinical and radiological outcomes of the children with congenital dislocation of the knee and hip who presented after six months of age. Methods All the consecutive children with congenital dislocation of the knee and hip joints were retrospectively reviewed. We included cases that were treated after six months of age and followed up for a minimum of two years. Twenty-four children with congenital dislocation of the knee and hip (thirteen with ligamentous laxity, eleven children with stiff joints) were included. The knee was dislocated in 45 limbs; the hip was dislocated in 40 instances. The knee joint dislocation was treated with quadricepsplasty in all twenty-four children (45 knees). The hip dislocation ( n = 32) was addressed with either closed reduction ( n = 8) or open reduction of the hip ( n = 24). Eight hip dislocations were not addressed. The outcome of the hip and knee was evaluated. Results The clinical and radiological outcomes were better in children with ligamentous laxity than without laxity. Twenty-two children were community walkers. An orthosis was needed in eight children. The frequency of spontaneous reduction of unreduced dislocation of the hip was noted in three children (5/8 hips). Conclusion Outcome in combined dislocation of knee and hip is good in most cases with surgical interventions. The outcome is better in children with ligamentous laxity. Spontaneous reduction of the dislocated hips might be achieved after gaining knee flexion following knee surgery for congenital the knee in a few cases.

Out-of-hospital analgosedation in trauma patients is challenging for emergency physicians due to associated complications. We compared peripheral nerve block (PNB) with analgosedation (AS) as an analgetic approach for patients with isolated extremity injury, assuming that prehospital required medical interventions (e.g. reduction, splinting of dislocation injury) using PNB are less painful and more feasible compared to AS. Thirty patients (aged 18 or older) were randomized to receive either ultrasound-guided PNB (10 mL prilocaine 1%, 10 mL ropivacaine 0.2%) or analgosedation (midazolam combined with s-ketamine or with fentanyl). Reduction-feasibility was classified (easy, intermediate, impossible) and pain scores were assessed using numeric rating scales (NRS 0-10). Eighteen patients were included in the PNB-group and twelve in the AS-group; 15 and 9 patients, respectively, suffered dislocation injury. In the PNB-group, reduction was more feasible (easy: 80.0%, impossible: 20.0%) compared to the AS-group (easy: 22.2%, intermediate: 22.2%, impossible: 55.6%; p = 0.01). During medical interventions, 5.6% [1/18] of the PNB-patients and 58.3% [7/12] of the AS-patients experienced pain (p<0.01). Recorded pain scores were significantly lower in the PNB-group during prehospital medical intervention (median[IQR] NRS PNB: 0[0-0]) compared to the AS-group (6[0-8]; p<0.001) as well as on first day post presentation (NRS PNB: 1[0-5], AS: 5[5-7]; p = 0.050). All patients of the PNB-group would recommend their analgesic technique (AS: 50.0%, p<0.01). Prehospital ultrasound-guided PNB is rapidly performed in extremity injuries with high success. Compared to the commonly used AS in trauma patients, PNB significantly reduces pain intensity and severity.

Background/aimTo compare outcome of early mobilisation and plaster immobilisation in patients with a simple elbow dislocation. We hypothesised that early mobilisation would result in earlier functional recovery.MethodsFrom August 2009 to September 2012, 100 adult patients with a simple elbow dislocation were enrolled in this multicentre randomised controlled trial. Patients were randomised to early mobilisation (n=48) or 3 weeks plaster immobilisation (n=52). Primary outcome measure was the Quick Disabilities of the Arm, Shoulder, and Hand (Quick-DASH) score. Secondary outcomes were the Oxford Elbow Score, Mayo Elbow Performance Index, pain, range of motion, complications and activity resumption. Patients were followed for 1 year.ResultsQuick-DASH scores at 1 year were 4.0 (95% CI 0.9 to 7.1) points in the early mobilisation group versus 4.2 (95% CI 1.2 to 7.2) in the plaster immobilisation group. At 6 weeks, early mobilised patients reported less disability (Quick-DASH 12 (95% CI 9 to 15) points vs 19 (95% CI 16 to 22); p<0.05) and had a larger arc of flexion and extension (121° (95% CI 115° to 127°) vs 102° (95% CI 96° to 108°); p<0.05). Patients returned to work sooner after early mobilisation (10 vs 18 days; p=0.020). Complications occurred in 12 patients; this was unrelated to treatment. No recurrent dislocations occurred.ConclusionsEarly active mobilisation is a safe and effective treatment for simple elbow dislocations. Patients recovered faster and returned to work earlier without increasing the complication rate. No evidence was found supporting treatment benefit at 1 year.Trial registration numberNTR 2025.

Dislocations are the intrinsic origin of crystal plasticity. However, initial high-density dislocations in work-hardened materials are commonly asserted to be detrimental to ductility according to textbook strengthening theory. Inspired by the self-organized critical states of non-equilibrium complex systems in nature, we explored the mechanical response of an additively manufactured medium entropy alloy with segregation-dislocation self-organized structures (SD-SOS). We show here that when initial dislocations are in the form of SD-SOS, the textbook theory that dislocation hardening inevitably sacrifices ductility can be overturned. Our results reveal that the SD-SOS, in addition to providing dislocation sources by emitting dislocations and stacking faults, also dynamically interacts with gliding dislocations to generate sustainable Lomer-Cottrell locks and jogs for dislocation storage. The effective dislocation multiplication and storage capabilities lead to the continuous refinement of planar slip bands, resulting in high ductility in the work-hardened alloy produced by additive manufacturing. These findings set a precedent for optimizing the mechanical behavior of alloys via tuning dislocation configurations. Textbook theory asserts that dislocation hardening inherently sacrifices ductility. Here, the authors report that high-density dislocations with segregation-modified configurations produced by additive manufacturing increase strength without compromising ductility.

We investigate the structure of 1/3 <0[bar.1]11> dislocations observed in [Bi.sub.2][Te.sub.3] nanowires. This particular type of dislocation is interesting because it has a large Burgers vector (b = 1.048 nm) with a component normal to the basal planes equal to the thickness of one full [Bi.sub.2][Te.sub.3] quintuple unit (i.e., c/3). Atomic-resolution high-angle annular dark-field scanning transmission electron microscopy observations show that the dislocations form with a complex dissociated core structure. This structure consists of two partial dislocations that separate a defected region consisting of a seven-plane-thick septuple unit, consistent with a local patch of [Bi.sub.3][Te.sub.4], rather than the normal [Bi.sub.2][Te.sub.3] quintuple layer structure. As we discuss, details of the core structure can be understood from an analysis of the crystallographic parameters of the observed partial dislocations. This analysis suggests a mechanism to accommodate the loss of tellurium through the heterogeneous nucleation and growth of seven-layer defects at 1/3 <0[bar.1]11>--type dislocations.

Background Dislocation after revision THA is a common complication. Large heads have the potential to decrease dislocation rate, but it is unclear whether they do so in revision THA. Questions/purposes We therefore determined whether a large femoral head (36 and 40 mm) resulted in a decreased dislocation rate compared to a standard head (32 mm). Methods We randomized 184 patients undergoing revision THA to receive either a 32-mm head (92 patients) or 36- and 40-mm head (92 patients) and stratified patients by surgeon. The two groups had similar baseline demographics. The primary end point was dislocation. Quality-of-life (QOL) measures were WOMAC and SF-36. The mean followup for dislocation was 5 years (range, 2–7 years); the mean followup for QOL was 2.2 years (range, 1.6–4 years). Results In the 36- and 40-mm head group, the dislocation rate was 1.1% (one of 92) versus 8.7% (eight of 92) for the 32-mm head. There was no difference in QOL outcomes between the two groups. Conclusions Our observations confirm a large femoral head (36 or 40 mm) reduces dislocation rates in patients undergoing revision THA at short-term followup. We now routinely use large heads with a highly crosslinked polyethylene acetabular liner in all revision THAs. Level of Evidence Level I, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

Objective To evaluate surgical strategies and clinical outcomes for atlantoaxial instability/dislocation (AAI/AAD) in Down syndrome (DS) patients. Methods A retrospective review was conducted on 12 DS patients with AAI/AAD treated between March 2018 and June 2024. Surgical plans were tailored based on reducibility: reducible cases underwent posterior atlantoaxial/occipitocervical fusion ( n  = 8), while irreducible cases received transoral anterior release combined with posterior fixation ( n  = 4). Outcomes were assessed through complications, radiographic parameters (anterior atlantodental interval, ADI), and neurological status (JOA score). Results The cohort (5 males, 7 females) aged 5–28 years (mean 11.3 ± 6.4) completed 1–6 year follow-up. Clinical presentations included myelopathy (75.0%, 9/12) and neck pain (25.0%, 3/12). Radiographic anomalies included os odontoideum (66.7%, 8/12) and odontoid fracture (8.3%, 1/12). Postoperative ADI significantly decreased from 8.95 ± 3.19 mm to 3.40 ± 0.81 mm ( P  < 0.05), with JOA scores improving from 10.92 ± 4.40 to 15.50 ± 2.43 ( P  < 0.05). Complications occurred in 25.0% (3/12): one surgical site infection managed by debridement, one dural tear repaired intraoperatively, and one hardware displacement requiring revision. Median fusion time was 6 months (range 4.5–16). All patients demonstrated neurological improvement except one with residual lower limb weakness. Conclusion DS patients with AAI/AAD frequently present with os odontoideum and spinal cord compromise, necessitating surgical intervention. Reducible dislocations may be effectively managed with posterior fusion alone, whereas irreducible cases require combined anterior–posterior approaches. Early surgical intervention is recommended for DS patients exhibiting os odontoideum with AAI/AAD due to elevated risk of progressive myelopathy.