Low-concentration distal nerve blocks with 0.125% levobupivacaine versus systemic analgesia for ambulatory trapeziectomy performed under axillary block: a randomized controlled trial.

BACKGROUND: Trapeziectomy is one of the most painful procedures in ambulatory surgery. This prospective randomized trial aimed to compare postoperative pain control using distal peripheral nerve blocks (dPNB) with a low concentration of a long-acting local anesthetic versus conventional systemic analgesia. METHODS: Fifty-two patients undergoing trapeziectomy were randomized to receive levobupivacaine 0.125% 5 mL on radial and median nerves at the elbow (dNB group), or not to receive these blocks (control group). In both groups, surgery was performed under axillary block (mepivacaine 1% 20 mL) and the same analgesic regimen was prescribed at discharge. The primary outcome was postoperative pain at 24 and 48 hours after surgery and maximum pain score on the first and second postoperative day. Secondary outcomes were duration of dPNB, rescue analgesia requirements, opioid-related side effects, consumption and effectiveness of antiemetic therapy, and upper limb motor block. RESULTS: Fifty patients were analyzed. Maximum pain intensity was moderate to severe (dPNB vs. control) in 33.3% vs. 92.3% (P=0.002) on the first day after surgery and 20.8% vs. 80.8% (P<0.001) on the second day. The average duration of analgesia after dPNB was 10 hours and no patient reported motor block. dPNB reduced rescue analgesia requirements and the incidence of postoperative nausea and vomiting (PONV). CONCLUSIONS: dPNB on target nerves provided better analgesia than systemic analgesia after trapeziectomy performed under axillary block. Opioid consumption and the incidence of PONV were lower in the dPNB group.

Impact of hip anatomical variations on the cartilage stress: a finite element analysis towards the biomechanical exploration of the factors that may explain primary hip arthritis in morphologically normal subjects.

BACKGROUND: Hip arthritis is a pathology linked to hip-cartilage degeneration. Although the etiology of this disease is not well defined, it is known that age is a determinant risk factor. However, hip arthritis in young patients could be largely promoted by biomechanical factors. The objective of this paper is to analyze the impact of some normal anatomical variations on the cartilage stress distributions numerically predicted at the hip joint during walking. METHODS: A three-dimensional finite element model of the femur and the pelvis with the most relevant axial components of muscle forces was used to simulate normal walking activity. The hip anatomical condition was defined by: neck shaft angle, femoral anteversion angle, and acetabular anteversion angle with a range of 110-130°, 0-20°, and 0-20°, respectively. The direct boundary method was used to simulate the hip contact. FINDINGS: The hydrostatic stress found at the cartilage and labrum showed that a ±10° variation with respect to the reference brings significant differences between the anatomic models. Acetabular anteversion angle of 0° and femoral anteversion angle of 0° were the most affected anatomical conditions with values of hydrostatic stress in the cartilage near 5MPa under compression. INTERPRETATION: Cartilage stresses and contact areas were equivalent to the results found in literature and the most critical anatomical regions in terms of tissue loads were in a good accordance with clinical evidence. Altogether, results showed that decreasing femoral or acetabular anteversion angles isolatedly causes a dramatic increase in cartilage loads.