Introduction: Chronic hip arthroplasty infection is a difficult situation to solve. The use of uncemented stem is questionable, as no antibiotic loaded cement is used to fix the implant. Bone deficiencies are often enlarged by the chronic infection process and the multiple previous surgeries. We report our experience in two stage revisions with massive allograft and uncemented distal locked stem.

Material and method: We have retrospectively reviewed 15 patients operated on from chronic hip arthroplasty infection and secondary large femoral defects. Two stages revision with a temporarily antibiotic loaded cement spacer and 6-weeks second look reconstruction were performed with massive proximal femoral allograft and a long distally locked stem. The uncemented stem was cemented into the allograft and remained uncemented in the recipient distal femur. Outcome was assessed regarding infection control, allograft complication and function according to the Merle d’Aubigné score.

Results: Patients mean age was 62 years (SD 11). Patients were already operated from the same hip 5.9 +/− 2.3 times before the actual procedure. Isolated microorganisms were MRSE (7), staph Aureus (4), MRSA (1), VRE (1), enterococcus (2). Muscle flaps were performed in 2 cases and discuss for 2 more. Allograft length was 22 +/− 9 cm. Antibiotic treatment was maintained for 4.6 +/− 2.5 months (median 3 months). Mean follow-up was 29 months (SD 26; median 23). Clinical outcome based on Merle d’Aubigné score is 5.3 +/− 3 before treatment and 13.8 +/− 2.5 at the last visit. Complications were registered in 4 cases. Infection recurrence was observed in 3 cases (2,7,20 months) but the function was preserved in all cases. One of them needed a two stage procedure with a new allograft after 19 months due to acute staph Aureus infection. One allograft was broken after 80 months and need one stage revision.

Discussion: While the treatment of these cases was particularly demanding as bone deficiencies and microorganisms antibiotic resistance were high, functional result obtained was good. When infection recurrence was observed, function remains preserved. The use of uncemented distal locked stem with a cemented massive allograft did not lead to mechanical or hardware problem and allow us to restore the bone stock and the gluteus tendons insertion. The use of a modular stem was very helpful in solving these complex situations. Massive allografts can be used in case of infection as antibiotic delivery system.