Does the residual displacement of pelvic ring affect the functional outcome in pelvic ring injures?

The effects of residual displacement on the functional outcome of the patient are not distinctly known and the acceptability criteria of residual displacement of the pelvic ring remain disputed. The purpose of this study is to evaluate the effect of residual displacement on functional outcome in pelvic ring injuries.

A total of 49 patients with pelvic ring injuries (both operative and non-operative) were followed up for six months. Anteroposterior (AP), Vertical and rotational displacements were measured at admission, after surgery and at six months. Resultant displacement (vector addition of AP and vertical displacement) was taken for comparison. Displacement was graded as excellent, good, fair and poor according to Matta's criteria. Functional outcome assessment was done at six months using Majeed score. Work adjusted Majeed score was calculated for non-working patients by taking the percentage score.

We compared the means of residual displacement with functional outcome (Excellent/Good/Fair) and found that there was no significant difference between the groups in operative (P=0.33) or non-operative patients (P=0.09). This showed that patients with relatively higher residual displacement also had satisfactory functional outcomes. The functional outcomes were compared after dividing the residual displacement into 2 groups: <10 mm and >10 mm and no significant difference was found in outcomes for either operative or non-operative patients.

Up to 10 mm of residual displacement is acceptable in pelvic ring injuries. More prospective studies with a longer follow up are needed for determination of correlation between reduction and functional outcome.