Bone graft incorporation after revision hip arthroplasty in patients with rheumatoid arthritis, seventy eight revisions using bone allografts with or without metal reinforcements

Revision of the acetabulum in the presence of severe loss of bone stock, especially in rheumatiod arthritis, has become a very difficult surgical problem. Transmission of disease is a potential hazard associated with the use of allograft. Therefore, in our series only morselized, frozen, radiation sterilized bone allografts were used. Experimental data showed only a small radiation influence on physical strength of allograft and on bone morphogenetic protein (BMP) [5‐7].

There is not much published data about the results of cup revision with bone grafting exclusively in rheumatoid patients. Schreurs et al. presented 35 consecutive acetabular revisions with bone grafting and cemented cups without any reinforcements. Four of those hips had a repeated revision because of aseptic (three hips) and septic loosening (one hip) [8‐10]. Raut et al. reported satisfactory results in 47 hips in 41 patients with RA. He also didn’t use any acetabular reinforcement, although 37 % (15 hips) of the sockets showed aseptic loosening. In two of these procedures, the authors used bone grafting only in cases when cavitary or small segmental wall defects of the acetabulum were contained with metal mesh and screw fixation [11]. Mont et al. reported low rate of success at an average of nine years after use of uncemented cups in RA patients. The chance of survival at 108 months was 44 % [12].

In other papers, rheumatoid patients weren’t assessed separately [10, 13, 14]. The rate of loosening revised cups due to bone graft resorption in the present study (10 %) is similar or even better to the results found in osteoarthritis (OA) patients, even when our patients used methotrexate (MTX) and steroids [10, 13, 14]. Hori et al. reported almost 20 % of revised cup loosening after using a Kerboull-type acetabular reinforcement device with bulky or impacted allografts. Patients were treated for primary OA and the mean follow-up was 7.5 years (minimum 2.1 years) [14]. Slightly better results were published by Akiyama et al., with the same type of reinforcement ring and bone grafts. Survival rate, calculated using radiological failure or revision, was 87 % at ten years [15], but their patients had less severe acetabular bone defects than patients of Hori et al. [14]. Bohm and Banzhaf reported a rate of 89 % with three reconstruction alternatives in 103 cases that were followed up for 0.3–13 years [16].

In our series, higher rates of bone graft resorption and loosening of rings and cages without primary good screw fixation like Mueller cage was caused by poor primary stabilization. The osteoporotic bone and one fixation point to the ilium bone produced micromovement of cages, which reduced the possibility of bone graft remodelling. In our group of Mueller cages, the loosening and bone graft resorption occurred in all five cases. The studies performed by Schatzeker et al., Zehtner and Ganz or Schreurs et al. illustrated similar poor results [8‐10, 17, 18].

In his paper, Markowich compared results from the literature after acetabular reconstruction: cemented or uncemented cups, several types of metal reinforcement, and morselized and structural bone graft. He noticed the best long-term results in Sloof’s reconstruction method and when Burch-Schneider cages were used [19]. Also, Bohm and Banzhaf reported better results with the use of the Burch-Schneider than the Harris-Galante cup or the Müller acetabular roof reinforcement ring after 11 years [16].

The use of the Burch-Schneider cage type is performed as our reconstruction method of choice when a metal support is needed. The relatively high rate of early dislocation in the beginning in our series of Burch-Schneider cages was caused by our poor technical experience in the fixation position of this cage. Later patients presented with good positioning of the cage, so no additional dislocation took place.

Hamadouche et al. proposed a novel technic for acetabular reconstruction using allograft bone, demineralised bone matrix (DBM) and the Kerboull acetabular device. So far, they have performed nine cases of type III acetabular deficiencies using this technique. No complications have been seen up to now, and gradual bone graft incorporation was observed. Bone remodeling was seen on radiographs by six months [20]. Longer follow-up and larger number of patients are needed to recommend this treatment for standard use.

Use of bone grafts for the reconstruction of the posterior acetabular wall after fracture was reported by Sen et al. After 3.2 months all grafts showed radiological signs of incorporation. At a mean follow-up of 3.34 years, two-thirds of patients had satisfactory radiological results and half of them had satisfactory clinical results [21].

In summary, acetabular reconstruction with the use of morselized, frozen, radiation sterilized bone allografts and acetabular cages with screw fixation to both the ilium and the ischium appears to be a valuable method of managing acetabular revision with bone defects in RA patients. There is no great difference in bone graft incorporation in RA and OA patients according to literature and our data. It is clear that longer-term follow-up will be needed to completely assess this reconstruction procedure.