Second-generation extensively porous-coated THA stems at minimum 10-year followup

Abstract

The relatively high prevalence of thigh pain and stress shielding associated with the AML porous-coated cementless femoral component led to the development of the Prodigy, a femoral component with more extensive porous-coating and a distal polished bullet tip with medial diaphyseal relief to potentially decrease the flexural rigidity. We prospectively evaluated a cohort of 100 consecutive cementless total hip arthroplasties performed using this device. The minimum followup was 10 years (mean, 11.4 years; range, 10-12 years). At 10-year followup, 69 of the 86 patients (82 hips) were living, 14 patients with 15 hips were deceased, and three patients with three hips were lost to followup. No hips required a stem revision. Two patients (two hips) complained of thigh pain. All hips were bone ingrown. Distal tip radiolucencies and osteolysis occurred in 13 hips (17%) and none, respectively. Twenty-one hips (28%) demonstrated moderate or severe stress shielding. Only further followup will determine if this could be a clinical problem or one with revision surgery. These results encourage the authors to continue using second-generation extensively coated stems in their primary total hip arthroplasty constructs.

Fig. 1

Survivorship curve was determined with revision of the hip for any reason as the end point. The probability of survival was 88% at 10 years. The 95% confidence intervals are designated by the dashed lines.

Fig. 2A–C

(A) Preoperative, (B) postoperative, and (C) 10-year followup radiographs show a 39-year-old male patient who underwent THA with a prodigy femoral component at age 28. Presently, he walks miles without assistance, golfs several times a week, and has a UCLA activity-level score of 7. The radiographs demonstrate bony ingrowth of the stem, moderate stress shielding and a radiodense line in the area of the medial cutout from reaming of the canal.