Purpose of this paper is to provide an overview of the latest research on the anterolateral ligament (ALL) and present the consensus of the ALL Expert Group on the anatomy, radiographic landmarks, biomechanics, clinical and radiographic diagnosis, lesion classification, surgical technique and clinical outcomes. A consensus on controversial subjects surrounding the ALL and anterolateral knee instability has been established based on the opinion of experts, the latest publications on the subject and an exchange of experiences during the ALL Experts Meeting (November 2015, Lyon, France). The ALL is found deep to the iliotibial band. The femoral origin is just posterior and proximal to the lateral epicondyle; the tibial attachment is 21.6 mm posterior to Gerdy’s tubercle and 4–10 mm below the tibial joint line. On a lateral radiographic view the femoral origin is located in the postero-inferior quadrant and the tibial attachment is close to the centre of the proximal tibial plateau. Favourable isometry of an ALL reconstruction is seen when the femoral position is proximal and posterior to the lateral epicondyle, with the ALL being tight upon extension and lax upon flexion. The ALL can be visualised on ultrasound, or on T2-weighted coronal MRI scans with proton density fat-suppressed evaluation. The ALL injury is associated with a Segond fracture, and often occurs in conjunction with acute anterior cruciate ligament (ACL) injury. Recognition and repair of the ALL lesions should be considered to improve the control of rotational stability provided by ACL reconstruction. For high-risk patients, a combined ACL and ALL reconstruction improves rotational control and reduces the rate of re-rupture, without increased postoperative complication rates compared to ACL-only reconstruction. In conclusion this paper provides a contemporary consensus on all studied features of the ALL. The findings warrant future research in order to further test these early observations, with the ultimate goal of improving the long-term outcomes of ACL-injured patients.
Level of evidence Level V—Expert opinion.
Parasympathetic nerves are a vital component of the progenitor cell niche during development, maintaining a pool of progenitors for organogenesis. Injured adult organs do not regenerate after parasympathectomy, and there are few treatments to improve organ regeneration, particularly after damage by therapeutic irradiation. Here we show that restoring parasympathetic function with the neurotrophic factor neurturin increases epithelial organ regeneration after damage. We use mouse salivary gland explant culture containing fluorescently-labeled progenitors, and injure the tissue with irradiation. The progenitors survive, parasympathetic function is diminished, and epithelial apoptosis reduces expression of neurturin, which increases neuronal apoptosis. Treatment with neurturin reduces neuronal apoptosis, restores parasympathetic function, and increases epithelial regeneration. Furthermore adult human salivary glands damaged by irradiation also have reduced parasympathetic innervation. We propose that neurturin will protect the parasympathetic nerves from damage and improve organ regeneration. This concept may be applicable for other organs where parasympathetic innervation influences their function.
Background
Residual rotational instability remains a controversial factor when analysing failure rates of anterior cruciate ligament (ACL) reconstruction. Anatomical and biomechanical studies have demonstrated a very important role of anterolateral structures for rotational control. Revision ACL is considered one of the main indications for a lateral extra‐articular tenodesis (LET). Yet, few series evaluating these procedures are published.
Purpose
To perform a systematic review of studies that assessed outcomes in patients treated with revision ACL surgery associated with a lateral extra‐articular procedure.
Study design
Systematic review.
Methods
A comprehensive literature search was performed in February 2018 using PubMed, Scopus, Web of Search and Cochrane. Inclusion criteria were series of ACL revision reconstructions associated with lateral extra‐articular procedures. Clinical outcomes (Lysholm, subjective IKDC, KOOS, Cincinnati and WOMAC), joint stability measures (Lachman test, pivot‐shift, arthrometer assessment and navigation assessment), graft type, reported chondral and meniscal injury, radiographic outcomes, complications and failures were recorded. Articles were assessed for level of evidence and methodology using a modification of the ACL Methodology Score (AMS) system.
Results
Twelve studies met the inclusion criteria out of the 231 abstracts; 9 retrospective evaluations, two prospective cohorts and one combination of two populations (a retrospective and prospective series). A total of 851 patients evaluated with a mean age of 28.8 years (range 16–68 years) and a weighted mean follow‐up of 4.9 years (range 1–10 years). The mean time from primary ACL reconstruction to revision was 5.3 years (reported in 7 studies, including 710 patients). The Lysholm, IKDC, and KOOS scores indicated favorable results in studies that reported these outcomes. Objective evaluations reported 86% objective A and B IKDC results, 2.6 mm mean side‐to‐side arthrometric difference and 80% negative pivot‐shift. About 74% of patients returned to their previous sport (evaluated in six studies). Few studies reported radiological evaluation. Fifty‐nine complications (8.0%) and 24 failures (3.6%) were reported. The mean modified ACL Methodology Score was 55.5 (range 32–72).
Conclusion
Good mid‐term results were obtained for combined revision ACL reconstruction and lateral extra‐articular procedures. Despite the fact that in clinical practice LET are a common indication associated with revision ACL, there are no high‐level studies supporting this technique.
Level of evidence
IV.
This paper describes the Sheffield Mk3.5 EIT/EIS system which measures both the real and imaginary part of impedance at 30 frequencies between 2 kHz and 1.6 MHz. The system uses eight electrodes with an adjacent drive/receive electrode data acquisition protocol. The system is modular, containing eight identical data acquisition boards, which contain DSPs to generate the drive frequencies and to perform the FFT used for demodulation. The current drive is in three sequentially applied packets, where each packet contains ten summed sine waves. The data acquisition system is interfaced to a host PC through an optically isolated high speed serial link (RS485) running at 2 Mbaud (2 Mbits s(-1)). Measurements on a saline filled tank show that the average signal to noise performance of the system is 40 dB measured across all frequencies and that this figure is independent of frequency of measurement. These results suggest that the current system is 10 dB better in absolute terms than the previous Sheffield (Mk3a) system.
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