PurposeMedial epicondyle fractures are among the most common pediatric elbow injuries. The management of these fractures continues to be debated. To better understand patient results with operative fixation, we reviewed the outcomes of operatively treated medial epicondyle fractures.MethodsA retrospective review was performed to identify all patients less than 18 years of age at the time of injury who were treated surgically for medial epicondyle fractures. Outcomes were assessed based on the Patient-Reported Outcomes Measurement Information System (PROMIS) Upper Extremity and Pain Interference domains, Visual Analog Scale for pain, subjective range of motion, ulnar nerve function, and requirement for secondary surgery.ResultsWe identified a cohort of 95 patients treated for a medial epicondyle fracture with open reduction and screw fixation. Of these, 39 patients with a mean age of 12.2 years (SD, 2.2 years; range, 7.6–16.0 years) at surgery were assessed for an average follow-up of 6.3 years (SD, 3.2 years; range, 2.2–13.9 years). Outcome measures and pain scores were excellent. The mean PROMIS Upper Extremity score was 56.9, the mean Pain Interference score was 38.5, and the mean Visual Analog Scale score was 0.4.Sixteen patients (41%) required secondary surgery for symptomatic hardware removal. Seven patients (18%) developed sensory complaints and 2 (5%) developed motor complaints consistent with ulnar nerve irritability. Three patients (8%) reported dissatisfaction with elbow range of motion. Patients who required secondary surgeries had higher (worse) PROMIS Pain Interference scores.ConclusionsAt an average of 6.3 years after surgery, the clinical outcomes for medial epicondyle fracture were excellent. While operative treatment for medial epicondyle fractures in children leads to excellent clinical outcomes, patients and surgeons should be aware of high rates of hardware removal.Type of study/level of evidenceTherapeutic IV

The published article contained four sentences with incorrect reference citations. Here, those sentences and the reference list are corrected.

The published article contained four sentences with incorrect reference citations. Here, those sentences and the reference list are corrected.

» Operative intervention for deficient hip abductor muscles may require muscle transfer or the use of synthetic materials, possibly with biologic augmentation, to help stabilize the hip joint and prevent further dislocation following total hip arthroplasty (THA). » Direct repair of the abductor mechanism onto the greater trochanter can be used in patients who present with instability <15 months following primary THA. » Augmentation of soft tissue with acellular dermal allografts can be considered for patients with abductor avulsion that requires posterior capsular reconstruction. » The Achilles tendon + calcaneal bone allograft is indicated for patients who have undergone multiple prior revision surgeries, who have experienced failure of nonoperative management, and have tissue inadequacy in the posterior wall of the hip joint. » The gluteus maximus tendon transfer is indicated in patients with chronic abductor tears, limited or loss of function in the gluteus medius and minimus, and a fully functioning gluteus maximus. » Vastus lateralis transfer may benefit patients with a history of multiple revision procedures, large separation between the gluteus medius tendon and the proximal part of the femur, and the ability to observe the postoperative protocol of splinting for 6 weeks. » The latissimus dorsi tendon transfer should be reserved as a reconstructive procedure for patients with acute abductor insufficiency, such as those who have undergone extensive tumor resection. » Synthetic mesh can be used to enable capsular reconstruction and prosthesis stabilization in patients undergoing salvage procedures for tumors of the hip and associated soft tissues. » Synthetic ligament prostheses can be used in patients with recurrent posterior dislocations in the setting of normal components. » The fascia lata plasty is indicated for patients with recurrent posterior instability without an identifiable cause. » Although the quality of literature is limited, surgical interventions utilizing techniques of soft-tissue augmentation have shown promising outcomes with regard to pain relief, limping, ambulation, and the reduction of instability following THA.

We assessed outcomes of 43 paediatric and adolescent patients (44 wrists) undergoing arthroscopic triangular fibrocartilage complex surgery by a single surgeon between 2003 and 2016. Medical records were reviewed for clinical, imaging, and operative data. Preoperatively, 49% of patients had additional diagnoses and mean QuickDASH was 47. Patients were telephoned to assess current wrist pain, subsequent treatment(s), satisfaction, and to complete QuickDASH and Patient-Rated Wrist Evaluation questionnaires. Twenty-five patients responded with mean follow-up of 70 months (minimum 13 months). In those patients not reached by telephone, mean clinical follow-up was 21 months. Seven patients had subsequent surgery (most commonly ulnar shortening osteotomy); this was associated with lower satisfaction scores. At final follow-up, mean QuickDASH was 4, Patient-Rated Wrist Evaluation 8 and patient and parent satisfaction scores were 9 and 9 out of 10, respectively. In conclusion, arthroscopic triangular fibrocartilage complex treatment in paediatric patients yielded favourable outcomes and patient/parent satisfaction. Level of evidence: IV

Background: Surgical resection is the cornerstone of curative-intent therapy for patients with hilar cholangiocarcinoma (HC). The role of vascular resection (VR) in the treatment of HC in western centres is not well defined. Methods: Utilizing data from the U.S. Extrahepatic Biliary Malignancy Consortium, patients were grouped into those who underwent resection for HC based on VR status: no VR, portal vein resection (PVR), or hepatic artery resection (HAR). Perioperative and long-term survival outcomes were analyzed. Results: Between 1998 and 2015, 201 patients underwent resection for HC, of which 31 (15%) underwent VR: 19 patients (9%) underwent PVR alone and 12 patients (6%) underwent HAR either with (n = 2) or without PVR (n = 10). Patients selected for VR tended to be younger with higher stage disease. Rates of postoperative complications and 30-day mortality were similar when stratified by vascular resection status. On multivariate analysis, receipt of PVR or HAR did not significantly affect OS or RFS. Conclusion: In a modern, multi-institutional cohort of patients undergoing curative-intent resection for HC, VR appears to be a safe procedure in a highly selected subset, although long-term survival outcomes appear equivalent. VR should be considered only in select patients based on tumor and patient characteristics.

During morphogenesis and cancer metastasis, grouped cells migrate through tissues of dissimilar stiffness. Although the influence of matrix stiffness on cellular mechanosensitivity and motility are well-recognized, it remains unknown whether these matrix-dependent cellular features persist after cells move to a new microenvironment. Here, we interrogate whether priming of epithelial cells by a given matrix stiffness influences their future collective migration on a different matrix – a property we refer to as the ‘mechanical memory’ of migratory cells. To prime cells on a defined matrix and track their collective migration onto an adjoining secondary matrix of dissimilar stiffness, we develop a modular polyacrylamide substrate through step-by-step polymerization of different PA compositions. We report that epithelial cells primed on a stiff matrix migrate faster, display higher actomyosin expression, form larger focal adhesions, and retain nuclear YAP even after arriving onto a soft secondary matrix, as compared to their control behavior on a homogeneously soft matrix. Priming on a soft ECM causes a reverse effect. The depletion of YAP dramatically reduces this memory-dependent migration. Our results present a previously unidentified regulation of mechanosensitive collective cell migration by past matrix stiffness, in which mechanical memory depends on YAP activity.

The Hippo pathway controls organ growth and is implicated in cancer development. Whether and how Hippo pathway activity is limited to sustain or initiate cell growth when needed is not understood. The members of the AJUBA family of LIM proteins are negative regulators of the Hippo pathway. In mammalian epithelial cells, we found that AJUBA LIM proteins limit Hippo regulation of YAP, in proliferating cells only, by sequestering a cytosolic Hippo kinase complex in which LATS kinase is inhibited. At the plasma membranes of growth-arrested cells, AJUBA LIM proteins do not inhibit or associate with the Hippo kinase complex. The ability of AJUBA LIM proteins to inhibit YAP regulation by Hippo and to associate with the kinase complex directly correlate with their capacity to limit Hippo signaling during Drosophila wing development. AJUBA LIM proteins did not influence YAP activity in response to cell-extrinsic or cell-intrinsic mechanical signals. Thus, AJUBA LIM proteins limit Hippo pathway activity in contexts where cell proliferation is needed.

The establishment and maintenance of apical-basal polarity is a defining characteristic and essential feature of functioning epithelia. Apical-basal polarity (ABP) proteins are also tumor suppressors that are targeted for disruption by oncogenic viruses and are commonly mutated in human carcinomas. Disruption of these ABP proteins is an early event in cancer development that results in increased proliferation and epithelial disorganization through means not fully characterized. Using the proliferating Drosophila melanogaster wing disc epithelium, we demonstrate that disruption of the junctional vs. basal polarity complexes results in increased epithelial proliferation via distinct downstream signaling pathways. Disruption of the basal polarity complex results in JNK-dependent proliferation, while disruption of the junctional complex primarily results in p38-dependent proliferation. Surprisingly, the Rho-Rok-Myosin contractility apparatus appears to play opposite roles in the regulation of the proliferative phenotype based on which polarity complex is disrupted. In contrast, non-autonomous Tumor Necrosis Factor (TNF) signaling appears to suppress the proliferation that results from apical-basal polarity disruption, regardless of which complex is disrupted. Finally we demonstrate that disruption of the junctional polarity complex activates JNK via the Rho-Rok-Myosin contractility apparatus independent of the cortical actin regulator, Moesin.

The mechanisms underlying collective migration are important for understanding development, wound healing, and tumor invasion. Here we focus on cell density to determine its role in collective migration. Our findings show that increasing cell density, as might be seen in cancer, transforms groups from broad collectives to small, narrow streams. Conversely, diminishing cell density, as might occur at a wound front, leads to large, broad collectives with a distinct leader-follower structure. Simulations identify force-sensitive contractility as a mediator of how density affects collectives, and guided by this prediction, we find that the baseline state of contractility can enhance or reduce organization. Finally, we test predictions from these data in an in vivo epithelium by using genetic manipulations to drive collective motion between predicted migratory phases. This work demonstrates how commonly altered cellular properties can prime groups of cells to adopt migration patterns that may be harnessed in health or exploited in disease.

Schimizzi and Longmore summarise what we know about Ajuba LIM-domain proteins and their various subcellular roles.

Individual microtubules (MTs) exhibit dynamic instability, a behavior in which they cycle between phases of growth and shrinkage while the total amount of MT polymer remains constant. Dynamic instability is promoted by the conserved XMAP215/Dis1 family of microtubule-associated proteins (MAPs). In this study, we conducted an in vivo structure-function analysis of the Drosophila homologue Mini spindles (Msps). Msps exhibits EB1-dependent and spatially regulated MT localization, targeting to microtubule plus ends in the cell interior and decorating the lattice of growing and shrinking microtubules in the cell periphery. RNA interference rescue experiments revealed that the NH(2)-terminal four TOG domains of Msps function as paired units and were sufficient to promote microtubule dynamics and EB1 comet formation. We also identified TOG5 and novel inter-TOG linker motifs that are required for targeting Msps to the microtubule lattice. These novel microtubule contact sites are necessary for the interplay between the conserved TOG domains and inter-TOG MT binding that underlies the ability of Msps to promote MT dynamic instability.

Background Chemotheraputic drugs often target the microtubule cytoskeleton as a means to disrupt cancer cell mitosis and proliferation. Anti-microtubule drugs inhibit microtubule dynamics, thereby triggering apoptosis when dividing cells activate the mitotic checkpoint. Microtubule dynamics are regulated by microtubule-associated proteins (MAPs); however, we lack a comprehensive understanding about how anti-microtubule agents functionally interact with MAPs. In this report, we test the hypothesis that the cellular levels of microtubule depolymerases, in this case kinesin-13 s, modulate the effectiveness of the microtubule disrupting drug colchicine. Methodology/Principal Findings We used a combination of RNA interference (RNAi), high-throughput microscopy, and time-lapse video microscopy in Drosophila S2 cells to identify a specific MAP, kinesin-like protein 10A (KLP10A), that contributes to the efficacy of the anti-microtubule drug colchicine. KLP10A is an essential microtubule depolymerase throughout the cell cycle. We find that depletion of KLP10A in S2 cells confers resistance to colchicine-induced microtubule depolymerization to a much greater extent than depletion of several other destabilizing MAPs. Using image-based assays, we determined that control cells retained 58% (±2%SEM) of microtubule polymer when after treatment with 2 µM colchicine for 1 hour, while cells depleted of KLP10A by RNAi retained 74% (±1%SEM). Likewise, overexpression of KLP10A-GFP results in increased susceptibility to microtubule depolymerization by colchicine. Conclusions/Significance Our results demonstrate that the efficacy of microtubule destabilization by a pharmacological agent is dependent upon the cellular expression of a microtubule depolymerase. These findings suggest that expression levels of Kif2A, the human kinesin-13 family member, may be an attractive biomarker to assess the effectiveness of anti-microtubule chemotherapies. Knowledge of how MAP expression levels affect the action of anti-microtubule drugs may prove useful for evaluating possible modes of cancer treatment.