Comparison of modular and nonmodular tapered fluted titanium stems in femoral revision hip arthroplasty: a minimum 6-year follow-up study.

Both modular and nonmodular tapered fluted titanium stems are commonly used in revision total hip arthroplasty (THA). However, which type of femoral stem is superior remains controversial. The purpose of this study was to assess the clinical and radiographic outcomes of modular and nonmodular tapered fluted titanium. The clinical data of patients undergoing primary revision THA from January 2009 to January 2013 in two institutions were retrospectively analyzed. According to the type of prosthesis used on the femoral side, the patients were divided into the modular group (108 hips; Link MP modular stem in 73 hips and AK-MR modular stem in 35 hips) and nonmodular group (110 hips; Wagner SL stem in 78 hips and AK-SL stem in 32 hips). The operative time, hospital stay, blood loss, blood transfusion volume, hip function, hip pain, limb length discrepancy, imaging data, and complications were compared between the two groups.A total of 218 patients were followed up for 78-124 months, with an average of 101.5 months. The incidence of intraoperative fracture in the modular group (16.7%) was significantly higher than that in the nonmodular group (4.5%; (P < 0.05). At the last follow-up, the limb length difference in the modular group (2.3 ± 2.7 mm) was significantly lower than that in the nonmodular group (5.6 ± 3.5 mm; P < 0.05), and the postoperative prosthesis subsidence in the modular group (averaged 0.92 mm; 0-10.2 mm) was significantly less than that in the nonmodular group (averaged 2.20 mm; 0-14.7 mm; P < 0.05). Both modular and nonmodular tapered fluted titanium stems can achieve satisfactory mid-term clinical and imaging results in patients who underwent femoral revision. The modular stems have good control of lower limb length and low incidence of prosthesis subsidence.