Direct Repair of Extensor Mechanism Disruption After Total Knee Arthroplasty “A Case Series of 31 Patients”

Background Extensor mechanism disruption following total knee arthroplasty is a destructive complication with poor outcomes. Presently, limited data exists regarding the direct repair therapy and long-term outcomes. This study was to evaluate the clinical results and complications of direct repair therapy, and compare it with similar studies to determine whether there is a better treatment. Methods During the period of 2008 to 2020, 31 patients underwent direct repair for an extensor mechanism disruption after total knee arthroplasty (15 patellar fractures, 9 patellar tendon disruptions, and 7 quadriceps tendon disruptions). Mean follow-up was 4.9 years. Demographic, operative, and clinical data were collected. The following statistical methods will be employed to analyze the data: descriptive statistics, paired t test, and the Kaplan-Meier method. Results For all 31 patients underwent direct repair for extensor mechanism disruption, 6 patients failed : 2 knees (6%) of infections and 4 knees (13%) of re-rupture. ROM was 94.1° ± 15.7° preoperatively to 73° ±52° postoperatively, average extensor lag reduced from 45° to 20.2° at follow-up, and the WOMAC and HSS averaged 65 and 72 points. The Kaplan-Meier estimated survivorship with failure for complications as the end point was 81% (95% confidence interval [95% CI], 42.7% to73.3%) at 12 years. Conclusion Direct repair of the extensor mechanism disruption is not an ideal therapy, it’s actually ineffective for the recovery of knee joint function in patients, and will remain severe knee extension lag. No matter which part of the extensor mechanism disruption, direct repair should not be the preferred treatment

Surgical management of the divided nerve

This chapter describes the principles of peripheral nerve repair by direct repair or nerve graft with specific discussion of assessment, exposure, and techniques of nerve repair. Notes on specific nerve injuries, neuroma management and outcomes are included.

Systematic analysis of factors that improve homologous direct repair (HDR) efficiency in CRISPR/Cas9 technique

The CRISPR/Cas9 bacterial system has proven to be an powerful tool for genetic manipulation in several organisms, but the efficiency of sequence replacement by homologous direct repair (HDR) is substantially lower than random indel creation. Many studies focused on improving HDR efficiency using double sgRNA, cell synchronization cycle, and the delivery of single-stranded oligo DNA nucleotides (ssODN) with a rational design. In this study, we evaluate these three methods’ synergistic effects to improve HDR efficiency. For our tests, we have chosen the TNFα gene (NM_000594) for its crucial role in various biological processes and diseases. For the first time, our results showed how the use of two sgRNA with asymmetric donor design and triple transfection events dramatically increase the HDR efficiency from an undetectable HDR event to 39% of HDR efficiency and provide a new strategy to facilitate CRISPR/Cas9-mediated human genome editing. Besides, we demonstrated that the TNFα locus could be edited with CRISPR/Cas9 methodology, an opportunity to safely correct, in the future, the specific mutations of each patient.

Histologic and Functional Outcomes of Conduit Wrapping for Peripheral Nerve Repair: Early Results in a Rat Model

Background The concept of utilizing a nerve conduit for augmentation of a primary nerve repair has been advocated as a method to prevent neural scarring and decrease adhesions. Despite clinical use, little is known about the effects of a nerve conduit wrapped around a primary repair. To better understand this, we investigated the histologic and functional effects of use of a nerve conduit wrapped around a rat sciatic nerve repair without tension. Methods Twenty Lewis' rats were divided into two groups of 10 rats each. In each group, unilateral sciatic nerve transection and repair were performed, with the opposite limb utilized as a matched control. In the first group, direct repair alone was performed; in the second group, this repair was augmented with a porcine submucosa conduit wrapped around the repair site. Sciatic functional index (SFI) was measured at 6 weeks with walking track analysis in both groups. Nonsurvival surgeries were then performed in all animals to harvest both the experimental and control nerves to measure histomorphometric parameters of recovery. Histomorphometric parameters assessed included total number of neurons, nerve fiber density, nerve fiber width, G-ratio, and percentage of debris. Unpaired t-test was used to compare outcomes between the two groups. Results All nerves healed uneventfully but compared with direct repair; conduit usage was associated with greater histologic debris, decreased axonal density, worse G-ratio, and worse SFI. No significant differences were found in total axon count or gastrocnemius weight. Conclusion In the absence of segmental defects, conduit wrapping primary nerve repairs seem to be associated with worse functional and mixed histologic outcomes at 6 weeks, possibly due to debris from conduit resorption. While clinical implications are unclear, more basic science and clinical studies should be performed prior to widespread adoption of this practice.

LIMBERG FLAP A BETTER METHOD OF CLOSURE OF LUMBAR MYELOMENINGOCELE DEFECTS: A PROSPECTIVE STUDY

Background: Myelomeningocele is the most common and complex congenital malformation of the central nervous system with an incidence of approximately 1 in 1000 live births. The lumbosacral area is the commonest site for defect. Early closure of a myelomeningocele defect is advocated because it reduces infection rates even though it is not associated with an improved neurological outcome. Aims & objectives: The aim of this study was to evaluate the effectiveness and outcome of direct repair and a Limberg ap repair for skin defects that occur in myelomeningocele. Settings and Design: This was a prospective, randomized controlled study. Material and methods: A tertiary care centre based, non-randomized, prospective, comparative study was conducted in the Department of Neurosurgery, GSVM Medical College, Kanpur, from January 2018 to October 2019, in 22 patients with lumbar myelomeningocele. 7 patients who underwent Limberg ap repair constituted Group A and 15 patients who underwent direct repair constituted Group B. Post operatively the outcomes were compared at 6 months, on the basis of cosmetic appearance and complications such as wound dehiscence, CSF leak, neurological decit, hydrocephalus, necrosis and wound infection. Results : Lesser complications and a better cosmetic outcome were seen post operatively at 6 months with Limberg ap technique compared to direct repair. Our study show better result with Limberg ap over direct repair of myelomeningocele defect closure up to the follow up period of 6 months. Conclusion: Because of various defect sizes and patient characteristics, no single protocol exists for the reconstruction of myelomeningocele defects. Most lumbar myelomeningocele defects can be managed by direct skin repair alone. In cases of large defects, in which direct repair is not possible, local aps may be used to cover the defect. Overall, Limberg ap is a better technique for closure in these patients.