Retrograde intramedullary nailing versus locked plate fixation for distal femur fractures: A systematic review and meta-analysis of randomised controlled trials only.

BACKGROUND

The optimal fixation method for distal femur fractures remains contentious. Retrograde intramedullary nailing (RIN) and locking plate fixation (PLATE) are the two principal surgical options, yet their comparative effectiveness has not been definitively established. This systematic review and meta-analysis aimed to comprehensively compare the operative, radiological, and functional outcomes of RIN versus PLATE for distal femur fractures exclusively from randomised controlled trials (RCTs).

METHODS

A systematic search of MEDLINE, Embase, Scopus and Web of Science was performed from inception to December 2025. Only RCTs directly comparing RIN with PLATE for distal femur fractures in adult patients were included. Risk of bias was assessed using the Cochrane Risk of Bias 2.0 tool. Random-effects meta-analyses were performed for 11 outcomes. Heterogeneity was quantified using I² statistics and prediction intervals. Subgroup analyses were conducted by fracture complexity, open fracture status, and follow-up duration.

RESULTS

Eighteen RCTs comprising 1105 patients (555 RIN, 550 PLATE) were included. RIN demonstrated significantly shorter operative duration (mean difference (MD) -13.75 min; 95% confidence interval (CI) -22.89 to -4.62; p = 0.003), faster fracture union time (MD -3.01 weeks; 95% CI -4.33 to -1.69; p < 0.001), and lower infection rates (risk ratio (RR) 0.54; 95% CI 0.30-0.98; p = 0.042). However, RIN was associated with significantly more knee pain (RR 1.68; 95% CI 1.14-2.48; p = 0.009) and less knee flexion (MD 4.04° favouring PLATE; 95% CI 0.51-7.58; p = 0.025). No significant differences were observed for non-union, delayed union, malalignment, implant failure, blood loss, re-operation, or functional scores.

CONCLUSION

RIN offers shorter operative duration, faster fracture union, and lower infection rates compared with plate fixation for distal femur fractures. However nailing causes significantly increased incidence of knee pain and slightly reduced knee flexion.

LEVEL OF EVIDENCE: Level 1- Systematic Review and Meta-Analysis of Randomised Controlled Trials.