Comparative study between fixed-angle and polyaxial screws in distal radius fixation with two volar locking plates.

INTRODUCTION: When treating a distal radius fracture with a volar locking plate (VLP), numerous plate-screw designs are available. To date, there is not a screw fastening system with a clear superiority among the others. HYPOTESIS: Fixed-angle screws are superior to polyaxial screws in distal radius VLP fixation with respect to screw protrusion and reduction preservation. MATERIAL AND METHODS: A prospective cohort study based on eighty patients was performed. The first forty patients were treated by polyaxial VLP (PA group) were the next forty by a fixed-angle VLP (FA group). Fixation was performed by the flexor carpi radialis approach. Screws were placed 2mm shorter than actual measurement and intraoperative AP, lateral and tilt wrist views were done routinely. A computed tomography (CT) was conducted searching for screw protrusion. Loss of reduction was calculated from the difference between post-operative x-rays values and those at the 6-month follow-up. The total follow-up was 12 months with no losses. RESULTS: Postoperative CT detected dorsal screw protrusion in 17 patients in PA group and 16 patients in FA group that intraoperative radiographs were assumed as correct (p=0.48). The mean invasion of dorsal cortex was of 2.2mm (1-7mm) for PA group and 2.6mm (1-5mm) for FA group (p=0.70). As from those protruding screws, the mean size was registered founding that fixed-angle screws had protrusions with shorter screws 20 vs. 22mm (p<0.05). Intraarticular screw protrusion was registered in 3 and 2 patients respectively (p>1.0). Experienced loss of reduction in volar tilt (p=0.42), radial inclination (p=0.75) and ulnar variance (p=0.83) were equivalent in both groups while a better preservation of the radial height in the PA group was observed (p<0.05). DISCUSSIONS: In terms of screw protrusion rate, both fastening systems where similar. However, fixed-angle group invaded the dorsal cortex with shorter screws. Polyaxial screws were associated with a better preservation of the radial height. Finally, this study reinforces the idea that dorsal and articular screw protrusion is more frequent than we expected. LEVEL OF EVIDENCE: II; therapeutic, prospective cohort study.

Common, intermediate and well-documented HLA alleles in world populations: CIWD version 3.0.0.

A catalog of common, intermediate and well-documented (CIWD) HLA-A, -B, -C, -DRB1, -DRB3, -DRB4, -DRB5, -DQB1 and -DPB1 alleles has been compiled from over 8 million individuals using data from 20 unrelated hematopoietic stem cell volunteer donor registries. Individuals are divided into seven geographic/ancestral/ethnic groups and data are summarized for each group and for the total population. P (two-field) and G group assignments are divided into one of four frequency categories: common (≥1 in 10 000), intermediate (≥1 in 100 000), well-documented (≥5 occurrences) or not-CIWD. Overall 26% of alleles in IPD-IMGT/HLA version 3.31.0 at P group resolution fall into the three CIWD categories. The two-field catalog includes 18% (n = 545) common, 17% (n = 513) intermediate, and 65% (n = 1997) well-documented alleles. Full-field allele frequency data are provided but are limited in value by the variations in resolution used by the registries. A recommended CIWD list is based on the most frequent category in the total or any of the seven geographic/ancestral/ethnic groups. Data are also provided so users can compile a catalog specific to the population groups that they serve. Comparisons are made to three previous CWD reports representing more limited population groups. This catalog, CIWD version 3.0.0, is a step closer to the collection of global HLA frequencies and to a clearer view of HLA diversity in the human population as a whole.

Graded Anderson procedure for correcting abnormal head posture in infantile nystagmus.

PURPOSE: To describe the long-term results of Anderson procedure, which includes recession of the two extraocular yoke muscles responsible for eccentric eye position and abnormal head posture (AHP) in patients with infantile nystagmus. METHODS: Retrospective data collection of patients who underwent an Anderson procedure at a single medical center by one surgeon from 2008 to 2016. The main outcome measure was the elimination of AHP following surgery. RESULTS: Twenty-seven patients (18 males, 9 females) underwent an Anderson procedure during the study period. The average age at surgery was 8.6 ± 7.7 years and mean follow-up was 3.5 ± 2.4 years (range, 6 months-9 years). Before surgery all patients had AHP (17 left and 10 right head turns) greater than 25° (mean 40.1 ± 6.7°) that decreased significantly following surgery (mean 7.2 ± 7.6°, P < 0.001). Surgery resulted in complete elimination of AHP in 14 (52%) patients. In 10 (37%) patients the residual head turn was 15° or lower, and in only 3 (8%) the post-operative AHP was 25° or larger, requiring further surgery. It is important to note that none of the patients developed strabismus or duction limitation following surgery. CONCLUSIONS: Long-term results following the Anderson procedure show a stable decrease in AHP in patients with infantile nystagmus, often resulting in complete restoration of normal head posture. Involved risks of strabismus and limitation of ocular motility appear to be low.