Transtibial fixation for medial meniscus posterior root tear reduces posterior extrusion and physiological translation of the medial meniscus in middle-aged and elderly patients.

PURPOSE: To investigate changes in meniscal extrusion during knee flexion before and after pullout fixation for medial meniscus posterior root tear (MMPRT) and determine whether these changes correlate with articular cartilage degeneration and short-term clinical outcomes. METHODS: Twenty-two patients (mean age 58.4 ± 8.2 years) diagnosed with type II MMPRT underwent open magnetic resonance imaging preoperatively, 3 months after transtibial fixation and at 12 months after surgery, when second-look arthroscopy was also performed. The medial meniscus medial extrusion (MMME) and the medial meniscus posterior extrusion (MMPE) were measured at knee 10° and 90° flexion at which medial meniscus (MM) posterior translation was also calculated. Articular cartilage degeneration was assessed using International Cartilage Research Society grade at primary surgery and second-look arthroscopy. Clinical evaluations included Knee Injury and Osteoarthritis Outcome Score, International Knee Documentation Committee subjective knee evaluation form, Lysholm score, Tegner activity level scale, and pain visual analogue scale. RESULTS: MMPE at 10° knee flexion was higher 12 months postoperatively than preoperatively (4.8 ± 1.5 vs. 3.5 ± 1.2, p = 0.01). MMPE at 90° knee flexion and MM posterior translation were smaller 12 months postoperatively than preoperatively (3.5 ± 1.1 vs. 4.6 ± 1.3, 7.2 ± 1.7 vs. 8.9 ± 2.0, p < 0.01). Articular cartilage degeneration of medial femoral condyle correlated with MMME in knee extension (r = 0.5, p = 0.04). All clinical scores significantly improved 12 months postoperatively. However, correlations of all clinical scores against decreased MMPE and increased MMME were not detected. CONCLUSIONS: MMPRT transtibial fixation suppressed the progression of MMPE and cartilage degeneration and progressed MMME minimally in knee flexion position at 1 year. However, in the knee extension position, MMME progressed and correlated with cartilage degeneration of medial femoral condyle. MMPRT transtibial fixation contributes to the dynamic stability of the MM in the knee flexion position. LEVEL OF EVIDENCE: IV.

Transtibial Pullout Repair Reduces Posterior Extrusion of the Medial Meniscus.

Medial meniscus posterior root tear causes rapid knee cartilage degradation by inducing posteromedial displacement of the medial meniscus. We evaluated medial meniscus posterior extrusion before and after pullout repair for medial meniscus posterior root tear using magnetic resonance images. Twenty-eight patients with symptomatic medial meniscus posterior root tear were included. The inclusion criteria were: acute (< 3 months) or chronic (≥3 months) medial meniscus posterior root tear after painful popping events. The exclusion criteria were: other meniscus and anterior cruciate ligament injuries. We measured medial meniscus posterior extrusion and medial meniscus anteroposterior interval at knee flexion angles of 10° and 90° preoperatively and at 3 months postoperatively. The posterior extrusion at 90° knee flexion decreased from 4.42±1.38 mm preoperatively to 3.09±1.06 mm (p<0.001) postoperatively, while at 10° knee flexion it was -4.17±1.63 mm preoperatively and -3.77±1.72mm postoperatively, showing no significant change. The anteroposterior interval at 10° knee flexion increased from 19.74±4.27 mm preoperatively to 22.15±5.10 mm postoperatively (p<0.001); at 90° knee flexion, it increased from 16.81±4.51 mm preoperatively to 19.20±4.30 mm postoperatively (p<0.001). Medial meniscus posterior extrusion and movement decreased after pullout repair. Pullout repair for medial meniscus posterior root tear improves medial meniscus posterior extrusion, especially at 90° knee flexion.

Navigated magnetic resonance imaging-guided celiac plexus neurolysis using an open magnetic resonance system for pancreatic cancer patients with upper abdominal pain.

AIMS: The study aimed to evaluate the safety and efficacy of navigated magnetic resonance imaging (MRI)-guided celiac plexus neurolysis (CPN) using a 0.4 T open magnetic resonance system. MATERIALS AND METHODS: A retrospective analysis was performed on 23 patients with unresectable pancreatic cancer who underwent MRI-guided CPN between January 2013 and October 2017. Clinical outcomes were evaluated by recording the complications, the opioid intake, and questionnaire before the intervention and at the time point of 1 day, 1 month, and 3 months postprocedure using a numerical visual analog scale (VAS). RESULTS: Navigated MRI guidance allowed the precise placement of needle in the targeted area and the visualization of the injected neurolysis agents for all cases. The VAS scores decreased from 8.8 ± 1.0 to 2.9 ± 0.9, 4.2 ± 1.7, and 4.7 ± 1.8 at 1 day, 1 month, and 3 months postprocedure (P < 0.05). This intervention reduced the dosage of opioid consumption 1 month after the procedure (52.3 ± 10.4 mg before the treatment vs. 28.2 ± 4.9 mg after the treatment; P < 0.001). Treatment-related side effects included hematoma in one patient, short episodes of diarrhea in three patients, and hypotension in four patients. CONCLUSIONS: With the assistance of the navigation system, MRI-guided CPN is a safe and effective treatment approach for managing the upper abdominal pain in patients with unresectable pancreatic cancer.

Meniscal repair concurrent with anterior cruciate ligament reconstruction restores posterior shift of the medial meniscus in the knee-flexed position.

PURPOSE: The purpose of this study was to evaluate the shape and shift of the medial meniscus before and after meniscal repair concurrent with anterior cruciate ligament (ACL) reconstruction using magnetic resonance imaging (MRI) at 90° of knee flexion. METHODS: This study included 18 patients with ACL-deficient knees without meniscus tears (group A), 11 patients with medial meniscus tears alone (group M), and 15 patients with ACL-deficient knees complicated with medial meniscus tears (group AM). The posterior segment shape was evaluated using open MRI at 90° of knee flexion preoperatively and at 3 months postoperatively. The length, height, width, and posterior extrusion of the medial meniscus and posterior tibiofemoral distance were measured. These measurements were compared between the three groups. RESULTS: On preoperative MRI, a significant difference was observed in the posterior extrusion of the medial meniscus (group A, 1.2 ± 0.5 mm; group M, 1.7 ± 0.3 mm; group AM, 4.1 ± 1.5 mm, p < 0.001). All parameters did not differ between the three groups on postoperative MRI. In addition, the posterior width and extrusion of the medial meniscus were decreased significantly after meniscal repair concurrent with ACL reconstruction. CONCLUSIONS: This study demonstrated that the medial meniscus shifted posteriorly at 90° of knee flexion in ACL-deficient knees complicated with medial meniscus tears. Medial meniscal repair concurrent with ACL reconstruction improved the deformed morphology and posterior extrusion. MRI measurements of the posterior extrusion at the knee-flexed position may be clinically useful to assess the functional improvement of the medial meniscus following meniscal repair combined with ACL reconstruction. LEVEL OF EVIDENCE: III.

Improvement in the medial meniscus posterior shift following anterior cruciate ligament reconstruction.

PURPOSE: Anterior cruciate ligament (ACL) reconstruction can reduce the risk of developing osteoarthritic knees. The goals of ACL reconstruction are to restore knee stability and reduce post-traumatic meniscal tears and cartilage degradation. A chronic ACL insufficiency frequently results in medial meniscus (MM) injury at the posterior segment. How ACL reconstruction can reduce the deformation of the MM posterior segment remains unclear. In this study, we evaluated the form of the MM posterior segment and anterior tibial translation before and after ACL reconstruction using open magnetic resonance imaging (MRI). METHODS: Seventeen patients who underwent ACL reconstructions without MM injuries were included in this study. MM deformation was evaluated using open MRI before surgery and 3 months after surgery. We measured medial meniscal length (MML), medial meniscal height (MMH), medial meniscal posterior body width (MPBW), MM-femoral condyle contact width (M-FCW) and posterior tibiofemoral distance (PTFD) at knee flexion angles of 10° and 90°. RESULTS: There were no significant pre- and postoperative differences during a flexion angle of 10°. At a flexion angle of 90°, MML decreased from 43.7 ± 4.5 to 41.4 ± 4.5 mm (P < 0.001), MMH from 7.5 ± 1.4 to 6.9 ± 1.4 mm (P = 0.006), MPBW from 13.1 ± 2.0 to 12.2 ± 1.9 mm (P < 0.001) and M-FCW from 10.0 ± 1.5 to 8.5 ± 1.5 mm (P < 0.001) after ACL reconstruction. The PTFD increased from 2.1 ± 2.8 to 2.7 ± 2.4 mm after ACL reconstruction (P = 0.015). CONCLUSIONS: ACL reconstruction affects the contact pattern between the MM posterior segment and medial femoral condyle and can reduce the deformation of the MM posterior segment in the knee-flexed position by reducing abnormal anterior tibial translation. It possibly prevents secondary injury to the MM posterior segment and cartilage that progresses to knee osteoarthritis. LEVEL OF EVIDENCE: IV.

The effect of mechanical strains in soft tissues of the shoulder during load carriage.

Soldiers and recreational backpackers are often required to carry heavy loads during military operations or hiking. Shoulder strain appears to be one of the limiting factors of load carriage due to skin and underlying soft tissue deformations, trapped nerves, or obstruction of blood vessels. The present study was aimed to determine relationships between backpack weights and the state of loads in the shoulder׳s inner tissues, with a special focus on the deformations in the brachial plexus. Open-MRI scans were used for developing and then verifying a three-dimensional, non-linear, large deformation, finite element model of the shoulder. Loads were applied at the strap-shoulder contact surfaces of the model by pulling the strap towards the shoulder until the desired load was reached. Increasing the strap tensile forces up to a load that represents 35kg backpack resulted in gradual increase in strains within the underlying soft tissues: the maximal tensile strain in the brachial plexus for a 25kg backpack was 12%, and while carrying 35kg, the maximal tensile strain increased to 16%. The lateral aspect of the brachial plexus was found to be more vulnerable to deformation-inflicted effects than the medial aspect. This is due to the anatomy of the clavicle that poorly shields the plexus from compressive loads applied during load carriage, while the neural tissue in the medial aspect of the shoulder is better protected by the clavicle. The newly developed model can serve as a tool to estimate soft tissue deformations in the brachial plexus for heavy backpack loads, up to 35kg. This method will allow further development of new strap structures and materials for alleviating the strains applied on the shoulder soft tissues.

Changes of Posterior Bulging of the Lumbar Intervertebral Discs with Flexion and Extension in Central Disc Bulges and Disc Degeneration

OBJECTIVE: To determine the changes of posterior bulging of the lumbar intervertebral discs with flexion and extension movement of the spine in patients with central disc bulges or disc degeneration. METHOD: Twenty patients with low back pain were studied. Nine patients had central type disc bulging and eleven patients had disc degeneration only. The spines were scanned in neutral, flexion, and extension positions in a vertically open 0.5T MR scanner. Degree of posterior bulging of the lumbar intervertebral disc of the pathological level was measured. RESULTS: In the patients with disc bulge, posterior bulging of the disc decreased in all of the patients by 0.8 0.6 mm with flexion of the spine and increased in 77.8% of the patients by 1.0 0.8 mm with extension of the spine. In the patients with disc degeneration, posterior bulging decreased with flexion in 36.7% of the patients. With extension, posterior bulging increased in 55.6% of the patients. CONCLUSION: This study found that patients with low back pain and central disc bulges have consistent and marked discrepancies in posterior bulging with flexion-extension in comparison with our previous study with asymptomatic patients with normal MRIs.