Outcomes of conversion total hip arthroplasty for failed fixation of intertrochanteric fractures with monoblock...

The aim of our study was to analyze the clinical and radiological outcomes of conversion total hip arthroplasty (THA) for failed fixation of proximal femur fractures with monoblock grit-blasted titanium reconstruction stem (Wagner self-locking stem, Zimmer).

Thirty-nine patients were included in this retrospective analysis undergoing conversion THA for failed cephalomedullary nail or dynamic hip screw fixation for intertrochanteric fractures from January 2017 to January 2022. The clinical evaluation was done using Harris hip score. The radiological outcomes measured were subsidence, level of osteointegration, stem-canal fill ratio and heterotopic bone formation. The complications were noted postoperatively and during the follow-up.

The mean follow-up at the end of the study was 27.8 months (range, 14-72 months). There was a significant improvement in the Harris hip score over serial follow-ups (p < 0.001), but after 2 years, there was no statistically significant difference (p = 0.46). According to Engh's criteria, stable ingrowth was noted in 35 stems, fibrous stable ingrowth was noted in 4 stems and no patients had progressive subsidence and unstable stem. The mean stem-canal fill percentages were 91.8 ± 5.4% at the mid-stem and 80.3 ± 11.5% at the stem tip. Heterotopic ossification Brooker grade 2 was noted in 8 patients, and no patients had grade 3 or 4 heterotopic ossification. There were 7 (17.9%) intraoperative periprosthetic fractures, and greater trochanteric avulsion was noted in 2 patients in the follow-up.

Conversion THA using monoblock tapered distal loading stems bypasses the calcar deficiency and gives stable fixation in failed fixation of intertrochanteric fractures. It gives good radiological outcome and significant improvement in the clinical outcomes compared to the preoperative disability. However, caution should be noted for risk of intraoperative periprosthetic fractures in this subgroup of patients.