[Translated article] Radiographic analysis for the selection of intramedullary screws for fixation of metacarpal fractures in the Colombian population.

OBJECTIVE To describe the variability in normal anatomical parameters of the second to fifth metacarpals according to age and sex, and to compare the results with the dimensions of the intramedullary screws available in Colombia for the fixation of metacarpal fractures.

METHODOLOGY This was an observational, descriptive, retrospective study. Normal PA and oblique radiographs were taken from 188 patients. The variables age, sex, length, isthmus diameter, isthmus distance, head width, dorsal lateral entry distance, and bicortical isthmus diameter were measured from the second to fifth metacarpals. The results will be presented stratified by age and sex as follows: 18-44 years, 45-64 years, and ≥65 years, and compared with the screws available for intramedullary fixation of the metacarpals.

RESULTS In total, images were studied from 188 patients with a mean age of 52.5 years. The index metacarpal was the longest on average, measuring 64.71mm. The mean distance from the metacarpal head to the isthmus was greatest in the index finger (38.21mm), followed by the middle finger (37.18mm). A wide range of isthmus diameters was found, with a minimum of 0.1mm in a ring finger and a maximum of 6.4mm in a middle finger. The proportion of the dorsal entry point distance in the oblique projection ranged from 0.29 to 0.33 of the total head width. Only one manufacturer's screws came in lengths between 20mm and 70mm and diameters between 1.8mm and 3.0mm; the remaining manufacturers produced screws less than 40mm in length.

CONCLUSIONS This study represents the first investigation to analyse the anatomical characteristics of the metacarpals in the Colombian population and compare them with the intramedullary screws available in the country. It seeks to provide surgeons with guidance for surgical planning in the context of fracture fixation with intramedullary screws.