Late versus early reduction in traumatic hip dislocations: a meta-analysis

Aims: Traumatic hip dislocations are considered orthopaedic emergencies that are treated with urgent reduction to decrease the rate of osteonecrosis of the femoral head. The aim of our study was to systematically review the literature that compares late (>6 h from the time of injury) to early (<6 h from the time of injury) reduction in all traumatic hip dislocations.

Materials and methods: We searched five databases from 1951 to 2016 for studies that evaluated timing of reduction and osteonecrosis of the femoral head in all traumatic hip dislocations. We performed a meta-analysis using a random-effects model to pool odds ratios (ORs) for a comparison of osteonecrosis of the femoral head between patients undergoing late versus early hip reduction. We also investigated the osteonecrosis rate in low- and high-grade traumatic hip dislocations. Descriptive, quantitative and qualitative data were extracted.

Results: Of the 13 articles identified, five studies (retrospective cohort studies) were eligible for the meta-analysis, encompassing a total of 236 traumatic hip dislocations. The pooled odds ratio for osteonecrosis of the femoral head between late and early reduction was in favour of early hip reduction and statistically significant (OR = 5.00, 95% CI: 1.30, 19.29). No significant difference in the rate of osteonecrosis of the femoral head was detected between low- and high-grade traumatic hip dislocations according to the time threshold (OR = 1.71, 95% CI: 0.22, 13.22).

Conclusions: The cumulative evidence at present does indicate an association between late hip reduction and higher rate of osteonecrosis of the femoral head in all traumatic hip dislocations. Hence, all traumatic hip dislocations should be reduced as soon as possible to decrease the rate of osteonecrosis of the femoral head. However, the evidence does not indicate an association between the grade of dislocation and rate of osteonecrosis of the femoral head.

Level of evidence: III.