A systematic review of clinical outcomes of pedicled flap repairs of the knee extensor mechanism.

Background Rupture of the extensor mechanism of the knee has severe functional morbidity, and repair can be complicated by infection, allograft degeneration, and recurrent rupture. Techniques of autologous tissue repair utilizing pedicled flaps such as the gastrocnemius offer vascularized methods of reconstruction, with potentially diminished complication rates. The goal of this study was to evaluate the functional outcomes and complications associated with pedicled flap repair of the knee extensor mechanism. Methods A systematic review was conducted following PRISMA guidelines. Publications that focused on local myocutaneous flaps as a means for reconstruction were included. Causes for knee extensor mechanism deficit, flap characteristics, ambulation rate, changes in range of motion pre- and post-operation, and postoperative complications were analyzed. Technique reports including primary suture repairs, synthetic mesh, and allograft use were excluded. Results An initial 119 studies were identified, with final review of 22 observational studies encompassing 128 cases of pedicled flap reconstructions. The gastrocnemius (88.2%, n=113), quadriceps (6.3%, n=8), and a combination of the vastus and gastrocnemius flaps (5.5%, n=7), were the most frequently utilized flaps. Functional outcomes were favorable with 87.2% of patients achieving ambulation without external support. Variability in range of motion outcomes across different flap may be secondary to the patient characteristics as well as extent of initial injury. Conclusions Autologous pedicle flap reconstruction of the knee extensor mechanism emerges as a viable option for cases characterized by extensive defects and insufficient soft tissue coverage, which are not amenable to direct suture repairs or allografts. Postoperative assessments revealed that the majority of patients experienced improved ambulation status, with no instances of deterioration noted among the patients.

Abdominal donor-site complications following autologous breast reconstruction: A multi-institutional multisurgeon study.

BACKGROUND: The deep inferior epigastric perforator (DIEP) free flap is the gold standard procedure for autologous breast reconstruction. Although breast-related complications have been well described, donor-site complications and contributing patient risk factors are poorly understood. METHODS: We examined a multi-institutional, prospectively maintained database of patients undergoing DIEP free flap breast reconstruction between 2015 and 2020. We evaluated patient demographics, operative details, and abdominal donor-site complications. Logistic regression modeling was used to predict donor-site outcomes based on patient characteristics. RESULTS: A total of 661 patients were identified who underwent DIEP free flap breast reconstruction across multiple institutions. Using logistic regression modeling, we found that body mass index (BMI) was an independent risk factor for umbilical complications (odds ratio [OR] 1.11, confidence interval [CI] 1.04-1.18, p = 0.001), seroma (OR 1.07, CI 1.01-1.13, p = 0.003), wound dehiscence (OR 1.10, CI 1.06-1.15, p = 0.001), and surgical site infection (OR 1.10, CI 1.05-1.15, p = 0.001) following DIEP free flap breast reconstruction. Further, immediate reconstruction decreases the risk of abdominal bulge formation (OR 0.22, CI 0.108-0.429, p = 0.001). Perforator selection was not associated with abdominal morbidity in our study population. CONCLUSIONS: Higher BMI is associated with increased abdominal donor-site complications following DIEP free flap breast reconstruction. Efforts to lower preoperative BMI may help decrease donor-site complications.

Analysis of Postoperative Distal Radius Fracture Outcomes in the Setting of Osteopenia and Osteoporosis for Patients with Comorbid Conditions.

Purpose: Distal radius fractures (DRFs) are among the most common orthopedic injuries, especially in the elderly. A wide variety of approaches have been advocated as successful treatment modalities; yet, there remains variability in practice patterns of DRF in patients with osteoporosis and osteopenia. Using large data set analysis, we sought to determine the risk profile of operative fixation of DRF in patients with low bone mineral density. Methods: A commercially available health care database, PearlDiver, was queried for all patients who underwent open reduction internal fixation of DRFs between 2010 and 2020. The study population was divided into groups based on the presence or absence of osteopenia or osteoporosis and was further classified by patients who were receiving bisphosphonate therapy. Complication rates were calculated, including rates of malunion, surgical site infection, osteomyelitis, hardware failure, and hardware removal. Five-year future fragility fractures were defined in hip, vertebrae, humerus, and wrist fractures. Chi-square analysis and logistic regression were performed to determine an association between these comorbidities and various postoperative complications. Results: A total of 152,926 patients underwent open reduction internal fixation of a DRF during the study period. Chi-square analysis of major complications at 3 months showed a statistically significant increase in malunion in patients with osteopenia (P = .05) and patients with osteoporosis (P = .05) who underwent open reduction internal fixation. Logistic regression analysis at 12 months after surgery demonstrated that osteopenia was associated with an increased risk of hardware failure (P < .0001), hardware removal (P < .0001), surgical site infection (P < .0001), and malunion (P = .004). Osteoporosis was associated with a significantly increased risk of hardware failure (P = .01), surgical site infection (P < .0001), and malunion (P < .0001). Conclusions: We demonstrated, using large data set analysis, that DRF patients with osteopenia and osteoporosis are predicted to be at increased risk of multiple postoperative complications, and thus, bone density should be strongly considered in treatment planning for these patients. Type of study/level of evidence: Prognostic III.

Outcomes following replantation surgery.

The ability to perform surgical replantation of individual digits and limbs can provide substantial functional improvement for patients who sustain devastating upper extremity injuries. Defining success in replantation surgery extends beyond the acute period and the binary metrics of survival or loss of the replanted part to include the long-term overall functional outcomes. Functional outcomes include both objective clinical evaluation and patient-reported outcomes. There has been significant variation in the way outcomes following replantation are measured, which inherently leads to heterogeneity in the reported outcome data. Given the variability among outcome measures, we aim to explore the outcomes of replantation surgery, particularly clinical evaluation and patient-reported functional outcomes following replantation.

Ulnar Nerve Compression at the Elbow Secondary to Intramuscular Lipoma of the Flexor Carpi Ulnaris: A Case Report.

CASE: A 62-year-old right-hand-dominant woman presented with 1 year of persistent radiating pain, weakness, and paresthesias in her left forearm and hand. Electromyography findings were significant for ulnar neuropathy distal to the branch innervating the flexor carpi ulnaris (FCU), without superimposed cervical radiculopathy or other focal entrapment neuropathy. During open ulnar nerve neurolysis, an intramuscular lipoma was encountered within the FCU. Lipoma excision and cubital tunnel release with ulnar nerve transposition were performed with complete relief of neuropraxia. CONCLUSION: We demonstrate full neurologic recovery after intramuscular lipoma excision and cubital tunnel release. Although rare, anomalous anatomy and tissue overgrowth should remain on the differential for patients presenting with atypical neuropraxia.

Venous Thromboembolism after Deep Inferior Epigastric Perforator Flap Breast Reconstruction: Review of Outcomes After a Postoperative Prophylaxis Protocol.

BACKGROUND: Deep inferior epigastric perforator (DIEP) flap breast reconstruction is among the higher-risk patient groups for venous thromboembolism (VTE) in plastic surgery. Surgeons often opt for a patient-specific approach to postoperative anticoagulation, and the field has yet to come to a consensus on VTE chemoprophylaxis regimens. METHODS: A new chemoprophylaxis protocol was introduced starting March 2019 that involved two weeks of treatment with enoxaparin, regardless of patient risk factors. A retrospective chart review was conducted on all patients who underwent DIEP flap breast reconstruction at our institution between January 2014 and March 2020. Patients were grouped based on whether they enrolled in the new VTE protocol in the postoperative period or not. Patient demographics, prophylaxis type, and outcomes data were recorded, retrospectively. The primary outcome measure was postoperative VTE incidence. RESULTS: Risk of VTE was significantly higher in patients discharged without VTE prophylaxis compared to patients discharged with prophylaxis (3.7% vs. 0%, p = 0.03). Notably, zero patients in the VTE prophylaxis group developed a DVT or PE. Additionally, the risk of a VTE event was 25 times greater in patients with a Caprini score greater than or equal to 6 (p=0.0002). CONCLUSIONS: We demonstrate the successful implementation of a two-week VTE chemoprophylaxis protocol in DIEP flap breast reconstruction patients that significantly reduces the rate of VTE while not affecting the rate of hematoma complications.

Plastic Surgery Training: Trends in Hand Surgery Fellowship in the Setting of a Pandemic.

Given the diminishing presence of hand surgeons trained in plastic surgery, we evaluated the associated trends in annual hand meeting educational content and postgraduate job offerings, and analyzed the effect of the coronavirus disease 2019 (COVID-19) pandemic on trainees in hand surgery. Methods: Hand meeting registration and educational content were analyzed over the past 10 years. Current hand surgery job offerings were evaluated for training requirements, and the annual rates of subspecialty certificate in surgery of the hand board certifications were compared across training backgrounds. Results: Top categories of annual meeting educational content were "bone/joint," "other," and "professional development." A majority of American Society for Surgery of the Hand presidents had training backgrounds in orthopedics (55%), followed by plastics (23%) and general surgery (22%). The job offerings on the American Society for Surgery of the Hand and Association for Surgery of the Hand websites specified more training requirements in orthopedics than in plastics. Additionally, there were two to three times as many examinees taking the surgery of the hand examination from orthopedic surgery compared with plastics, with an overall higher pass rate. Hand fellowship programs were also predominantly offered for orthopedic surgery (80.8%). Conclusions: Optimization of training, society membership, and clinical practice profiles may increase the presence of plastic surgery-trained hand surgeons. The extent of the economic impact of the COVID-19 pandemic is yet to be fully determined, but our analysis suggests that a lucrative market for reconstructive/hand surgery may exist in the face of economic downturn.

A Rare Case of Traumatic Acute Pronator Syndrome in the Setting of Anticoagulation Therapy.

Pronator syndrome (PS) is a rare type of peripheral compression neuropathy in which the median nerve becomes entrapped as it passes through the pronator teres muscle at the proximal forearm. We report an unusual case of acute PS in a 78-year-old patient on warfarin who presented after traumatic forearm injury with forearm swelling, pain, and paresthesias. After emergent nerve decompression and hematoma evacuation, the patient regained near complete recovery of median nerve function six months after diagnosis and treatment.

A rare case of rhabdomyosarcoma identified in a VRAM flap after lower extremity reconstruction.

Spindle cell sclerosing rhabdomyosarcoma (sc-RMS) is an extremely rare soft tissue tumor. We report an unusual case of sc-RMS in a 36-year-old patient whose tumor arose in a rectus abdominis muscle free flap that had been used for lower extremity reconstruction 18 years previously. After surgical excision of the tumor and immediate reconstruction, the patient has remained in remission and has full function of his lower extremity six months after diagnosis and treatment.

Damage to the Temporal Branch of the Facial Nerve From Mohs Micrographic Surgery.

BACKGROUND: The temporal branch of the facial nerve is at risk of damage during Mohs micrographic surgery (MMS). This complication leads to motor deficit in the ipsilateral upper face with resultant functional and cosmetic impairment. OBJECTIVE: To identify patient, tumor, and surgical risk factors associated with temporal nerve damage. MATERIALS AND METHODS: A single-institution, retrospective review of MMS cases involving anatomic sites within the temporal nerve danger zone was performed. Risk factors were compared between cases with and without nerve damage. RESULTS: Of 616 cases within the danger zone, 28 (4.5%) had postoperative nerve dysfunction. Variables significantly associated with dysfunction included patient immunosuppression, tumor size, aggressive tumor histology, recurrent tumors, high degree of subclinical spread, and greater average number of Mohs stages. Preoperative tumor size and postoperative defect size of ≥3 cm resulted in a ×37 and ×40 increased odds of nerve damage, respectively. Sex, age, and basal versus squamous cell carcinoma were not significantly associated with temporal nerve damage. No patients with a postoperative defect size measuring <2 cm had nerve damage. CONCLUSION: The overall risk of damage to the temporal nerve during MMS is low, but there are certain risk factors that warrant increased counseling about this potential complication.

Germline ETV6 mutation promotes inflammation and disrupts lymphoid development of early hematopoietic progenitors.

Germline mutations in ETV6 are associated with a syndrome of thrombocytopenia and leukemia predisposition, and ETV6 is among the most commonly mutated genes in leukemias, especially childhood B-cell acute lymphoblastic leukemia. However, the mechanisms underlying disease caused by ETV6 dysfunction are poorly understood. To address these gaps in knowledge, using CRISPR/Cas9, we developed a mouse model of the most common recurrent, disease-causing germline mutation in ETV6. We found defects in hematopoiesis related primarily to abnormalities of the multipotent progenitor population 4 (MPP4) subset of hematopoietic progenitor cells and evidence of sterile inflammation. Expression of ETV6 in Ba/F3 cells altered the expression of several cytokines, some of which were also detected at higher levels in the bone marrow of the mice with Etv6 mutation. Among these, interleukin-18 and interleukin-13 abrogated B-cell development of sorted MPP4 cells, but not common lymphoid progenitors, suggesting that inflammation contributes to abnormal hematopoiesis by impairing lymphoid development. These data, along with those from humans, support a model in which ETV6 dysfunction promotes inflammation, which adversely affects thrombopoiesis and promotes leukemogenesis.

ETV6-related thrombocytopenia and platelet dysfunction.

We and others recently described families with germline heterozygote mutations in ETV6 leading to autosomal dominant highly penetrant thrombocytopenia, red cell macrocytosis and predisposition to leukemia.The bone marrow of affected individuals shows erythroid dysplasia and hyperplasia of small, hypolobulated immature megakaryocytes suggesting a differentiation arrest. This discovery led to subsequent studies that confirmed our findings and to additional larger studies that demonstrated a 1% frequency of germline ETV6 mutations among 4405 individuals with acute lymphoblastic leukemia. Additionally, a 4.5% prevalence of ETV6 germline mutations was reported in families with inherited thrombocytopenia. Preliminary data suggest that decreased ETV6 function leads to MK maturation arrest, impaired platelet production and differentially expressed platelet transcripts among individuals affected with ETV6 mutations when compared to control relatives. Additionally, individuals with some ETV6 mutation exhibit bleeding that appears disproportionate to the mildly reduced platelet count, suggesting a platelet function deficit. Furthermore, recent studies describe decreased ability of platelets from individuals with ETV6 mutations to spread on fibrinogen covered surfaces. Overall, ETV6 germline mutations represent a new cancer predisposition thrombocytopenia with platelet dysfunction.

ETV6 germline mutations cause HDAC3/NCOR2 mislocalization and upregulation of interferon response genes.

ETV6 is an ETS family transcription factor that plays a key role in hematopoiesis and megakaryocyte development. Our group and others have identified germline mutations in ETV6 resulting in autosomal dominant thrombocytopenia and predisposition to malignancy; however, molecular mechanisms defining the role of ETV6 in megakaryocyte development have not been well established. Using a combination of molecular, biochemical, and sequencing approaches in patient-derived PBMCs, we demonstrate abnormal cytoplasmic localization of ETV6 and the HDAC3/NCOR2 repressor complex that led to overexpression of HDAC3-regulated interferon response genes. This transcriptional dysregulation was also reflected in patient-derived platelet transcripts and drove aberrant proplatelet formation in megakaryocytes. Our results suggest that aberrant transcription may predispose patients with ETV6 mutations to bone marrow inflammation, dysplasia, and megakaryocyte dysfunction.

Genomics and transcriptomics of megakaryocytes and platelets: Implications for health and disease.

The field of megakaryocyte and platelet biology has been transformed with the implementation of high throughput sequencing. The use of modern sequencing technologies has led to the discovery of causative mutations in congenital platelet disorders and has been a useful tool in uncovering many other mechanisms of altered platelet formation and function. Although the understanding of the presence of RNA in platelets is relatively novel, mRNA and miRNA expression profiles are being shown to play an increasingly important role in megakaryopoiesis and platelet function in normal physiology as well as in disease states. Understanding the genetic perturbations underlying platelet dysfunction provides insight into normal megakaryopoiesis and thrombopoiesis, as well as guiding the development of novel therapeutics.

Ena/VASP proteins regulate activated T-cell trafficking by promoting diapedesis during transendothelial migration.

Vasodilator-stimulated phosphoprotein (VASP) and Ena-VASP-like (EVL) are cytoskeletal effector proteins implicated in regulating cell morphology, adhesion, and migration in various cell types. However, the role of these proteins in T-cell motility, adhesion, and in vivo trafficking remains poorly understood. This study identifies a specific role for EVL and VASP in T-cell diapedesis and trafficking. We demonstrate that EVL and VASP are selectively required for activated T-cell trafficking but are not required for normal T-cell development or for naïve T-cell trafficking to lymph nodes and spleen. Using a model of multiple sclerosis, we show an impairment in trafficking of EVL/VASP-deficient activated T cells to the inflamed central nervous system of mice with experimental autoimmune encephalomyelitis. Additionally, we found a defect in trafficking of EVL/VASP double-knockout (dKO) T cells to the inflamed skin and secondary lymphoid organs. Deletion of EVL and VASP resulted in the impairment in α4 integrin (CD49d) expression and function. Unexpectedly, EVL/VASP dKO T cells did not exhibit alterations in shear-resistant adhesion to, or in crawling on, primary endothelial cells under physiologic shear forces. Instead, deletion of EVL and VASP impaired T-cell diapedesis. Furthermore, T-cell diapedesis became equivalent between control and EVL/VASP dKO T cells upon α4 integrin blockade. Overall, EVL and VASP selectively mediate activated T-cell trafficking by promoting the diapedesis step of transendothelial migration in a α4 integrin-dependent manner.