To report mid-term results of PJI treated with uncemented stems.

: 80 hips of PJI after THA were treated with uncemented stems from 01/1993 to 12/2012 and followed prospectively. Selection occurred for one- (n=27) or two-stage (n=53) exchange according to the Liestal algorithm. Surgical approaches were transfemoral (n=58), transgluteal (n=9) or transtrochanteric (n=13). A monoblock (Wagner SL, n=58) or modular (Revitan, n=22) revision stem was implanted. On the acetabular side 44 Müller rings, 33 Burch-Schneider cages (combined with a cemented PE-cup) and 3 press-fit cups were used. Kaplan-Meier survival was calculated for endpoints (a) persistence of infection, (b) septic/aseptic stem loosening. Radiographs were analysed for (a) subsidence, (b) distal stem integration, (c) changes in cortical thickness, (d) proximal femur restoration, (e) radiolucency around stem/cup.

Mean FU was 5.2 (2–15) years. PJI was eradicated in 77 of 80 hips (96%). 3 patients (all two-stage) had a treatment failure. 2 were treated successfully with an additional two-stage exchange. In the 3rd patient we were not able to control infection and exarticulation was performed. Furthermore, one stem was revised for aseptic loosening (5 years), 1 for a broken Wagner stem (7 years) and 1 for subsidence (8 months). Stem survival after 5 years was 93% (SD ±2.5 years). 2 cups were revised for aseptic loosening and 1 for recurrent dislocations. Subsidence ≥5mm was found in 6 hips and occurred always within 3 months after surgery independent of stem type (p=0.947) and approach (p=0.691). Proximal femoral remodelling after transfemoral approach was excellent or good in 71% (32 excellent, 9 good) with no difference between one-/two-stage exchanges (p=0.288). Initial distal stem integration was 65mm medial and 66mm lateral and increased to 8mm medial (p=0.716) and 10mm lateral (p<0.001). Cortical thickness was unchanged over the entire FU period (p=0.493). Radiolucencies were seen around 26 stems, only the stem revised after 5years was rated loose.

Eradication of PJI was high using our established protocol even with uncemented revision stems. Mid-term survival was independent from one-/two-stage revision and comparable to results for aseptic loosening revision.