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.

Debridement, antibiotics and implant retention (DAIR) is an established treatment option for periprosthetic joint infection (PJI). Success rates of more than 90% cure have been reported with proper patient selection. While a meticulous debridement of the joint and an appropriate postoperative antibiotic therapy is important for treatment success, the relevance of changing mobile parts is still a matter of debate. The latter procedure is only possible with an extensive soft tissue release, potentially destabilizing the joint. Though, it is impossible with polyethylene-inlays being no longer available. The aim of this study was to evaluate whether cure of PJI with DAIR is influenced by retaining the mobile parts.

Between 01/2004 and 12/2012, 36 patients with 39 episodes of THA-associated infections were treated with DAIR according to our algorithm (NEJM 2004). All patients met the IDSA criteria for DAIR with a stable implant and either a PJI diagnosed during the first postoperative month or a haematogenous PJI with infectious symptoms of less than three weeks. Patients were treated either with a complete debridement, including an exchange of all mobile parts (n=24), or with a complete debridement and retaining mobile parts (n=15). Postoperatively all patients received standardized antibiotic treatment (NEJM 2004).

The patients’ mean age at the time of infection was 74 (SD 9) years. Average time between onset of symptoms and DAIR were 3.6 (0–28) days; Five patients died before the 2-year-follow-up unrelated to PJI. Mean follow-up of the remaining patients was 45.6 (24–119) months. 20 PJI were early postoperative, 15 haematogenously acquired, and four unclear. The most frequent causative microorganisms were coagulase-negative staphylococci (n=16), S. aureus (n=8), streptococci (n=5) and E. coli (n=2). Ten episodes were polymicrobial, and nine cases culture-negative. The overall success rate of all 39 episodes treated with DAIR was 95% (37/39). Two treatment failures were observed, both after haematogenous S. aureus infection and exchange of mobile parts. One of them refused further surgery and was treated with a suppressive antibiotic therapy. The other one had a one-stage exchange four months after DAIR showing a loose cup intraoperatively.

Patients treated with DAIR strictly according to our treatment algorithm show a favourable result regarding overall success rate. From our data it seems debatable, whether the exchange of all mobile parts is mandatory, or should be individually evaluated in each case.