Retrograde Intramedullary Nailing Versus Locked Plating for Extreme Distal Periprosthetic Femur Fractures: A Multicenter Retrospective Cohort Study

Abstract

OBJECTIVE: To compare clinical and radiographic outcomes following retrograde intramedullary nailing vs locked plating of “extreme distal” periprosthetic femur fractures, defined as those which contact or extend distal to the anterior flange. METHODS Design: Retrospective review Setting: Eight academic level I trauma centers Patient Selection Criteria: adult patients with periprosthetic distal femur fractures at or distal to the anterior flange (OTA/AO 33B-C[VB1]) treated with rIMNs or LPs. Outcome Measures and Comparisons: The primary outcome was reoperation to promote healing or to treat infection (re-operation for elective removal of symptomatic hardware was excluded from this analysis). Secondary outcomes included nonunion, delayed union, fixation failure, infection, overall reoperation rate, distal femoral alignment, and ambulatory status at final follow-up. Compared, were patients treated with rIMNs or LPs. RESULTS: 71 patients treated with rIMNs and 224 patients treated with LPs were included. The rIMN group had fewer points of fixation in the distal segment (rIMN: 3.5 +/- 1.1 vs LP: 6.0 +/- 1.1, p<0.001) and more patients who were allowed to weight-bear as tolerated immediately post-operatively (rIMN: 45%; LP: 9%, p<0.01). Reoperation to promote union and/or treat infection was 8% in the rIMN group and 16% in the LP group (p=0.122). There were no significant differences in nonunion (p >0.999), delayed union (p=0.079), fixation failure (p>0.999), infection (p=0.084), or overall reoperation rate (p>0.999). Significantly more patients in the rIMN group were ambulatory without assistive devices at final follow-up (rIMN: 35%, LP: 18%, p=0.008). CONCLUSIONS: Retrograde intramedullary nailing of extreme distal periprosthetic femur fractures has similar complication rates compared to locked plating, with a possible advantage of earlier return to weight-bearing. Surgeons can consider this treatment strategy in all fractures with stable implants and amenable prosthesis geometry, even extreme distal fractures. Level of Evidence: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.