Search

The authors report on three cases in which a custom-made 3D printed titanium acetabular component of total hip arthroplasty was used to manage an advanced acetabular bone defect with pelvic discontinuity. The implant surface structure impeded long-term bone integration. Nonetheless, the stable bridging of the acetabular defect resulted in full integration of impacted bone allografts at the base of the implant. The pelvic continuity was restored within 12 months after surgery, and thus the acetabulum was prepared for potential further implantation of a standard revision acetabular component. Only one of the three female patients underwent a revision surgery at 18 months after surgery, the other two female patients were satisfied to such a degree with the clinical outcome at 6 years and 5 years, respectively, after surgery that they refused to undertake the revision surgery, despite X-ray images showing signs of loosening of the custom-made titanium acetabular component. The authors concluded that the implantation technique of three-point fixed custom-made 3D printed acetabular component made of titanium combined with impaction grafting of the acetabular base is a good alternative in managing the advanced bone defects of acetabulum with pelvic discontinuity after the failure of total hip arthroplasty. Even though inadequate surface porosity of the thus produced component did not allow its permanent osteointegration, the assembly was stable enough to allow the bone allografts to rebuild and restore continuity of the pelvis and facilitated future implantation of the standard revision acetabular component. Key words: 3D printing, individual acetabular component, titanium, total hip prosthesis, revision hip arthroplasty, acetabular reconstruction, custom-made implants.

The authors present an overview of the current views on etiology and diagnostics of infectious complications of total hip arthroplasty and analyze the possibilities of individual therapeutic procedures (debridement with the preservation of total hip arthroplasty, revision of the endoprosthesis, long-term antibiotic therapy, final resection arthroplasty, arthrodesis). They discuss the pending issues relating to the therapy of infectious complications of total hip arthroplasty (the duration of antibiotic therapy, the interval between the extraction and revision surgery of the endoprosthesis, the use of antibiotic-containing cement). Based on their own experience they recommend the revision surgery with the preservation of the implant, debridement and irrigation as the first step only in case of an early post-operative infection and in case of a late hematogenous acute infection. In case of chronic infection they recommend a two-step revision surgery using the cement spacer and the antibiotic therapy for 3 to 6 months. During this period the laboratory and clinical signs of the infection must be back to their normal. Long-term antibiotic therapy in dependence on microbial sensitivity is recommended.

Purpose of the Study: Since 1993 we have been using the Wagner revision stem, initially in the length of 265 mm and 305 mm and later also the short stem of 190 mm and 225 mm, for revision surgery with the destruction of proximal femur. This technique provided for primary fixation of the stem in the unaffected femoral bone and creates prerequisites for the bone regeneration and bone formation of the destructed host bone by the loosened implant in the metaphysis and proximal part of diaphysis., Material and Methods: In the period of 1993-1998 we operated on and followed a group of 35 patients (18 men and 17 women), average age 69 years (age range, 52-89). In 32 patients we performed revision surgery of Poldi-Cech stem, twice CF-30 stem and once cementless J + J stem. The average time interval between the primary operation and revision surgery was 10 years (range, 2-22 years). Thirty patients had to be reoperated due to aseptic loosening of the implant and five patients due to infection. Wagner stem was applied no sooner than 6 months after the infect had healed. In the application of the short stem (190 mm or 220 mm) we use Bauer approach (4 times) or extended Bauer approach (4 times), in long stems we use transfemoral approach in our modification: osteotomy is performed from the extended Bauer approach in the frontal plane and the anterior part of femoral cortex is retracted. The retracted anterior part of the femoral cortex femoral bone is fixed back only by hemi-wire loops., Results: Of the total number of 35 operated on 2 patients required revision surgery due to the subsidence of the stem and one removal of the stem in case of complete protrusion of the cup into pelvis. In short stems there were no post-operative complications. Dislocation of the hip occurred in three patients after the implantation of the long stem. After the closed reduction the surgery was not necessary. In one patient there developed an infection 5 months after operation. It was a hematogenous infect resulting from a pyogenic affection of the operated on limb. A two-step revision surgery was performed with a spacer and a subsequent reimplantation of a stem of greater diameter., Discussion: Wagner presents results of 69 patients after the application of his own stem 265 mm and 305 mm long. In 62 patients of the total number no subsidence was encountered, in two cases post-operative dislocation was recorded. Isakson et al. do not consider subsidence resulting in fixation of the stem as a significant factor and correct the difference in the length by shoes. They point out that this method is suitable for the solution of defects of proximal femur in such a way that the implant has a stable fixation and provides for bone formation, restoration of the destructed part of proximal femur in the extent of the original loosened stem. We consider the Wagner technique a significant contribution to the solution of these severe complications. As compared to Wagner, instead of the sagittal plane we perform transfemoral approach in the frontal--horizontal plane which allows operation in the supine position of the patient and a more precise replacement of the cup. In our group of patients we incorrectly used the long stem without transfemoral approach in 3 patients, one patient required revision surgery, in the remaining two patients the period of osteointegration of the stem was substantially longer., Conclusion: The Wagner revision stem allows treatment of the destructed proximal part of femur caused by loosening of the stem and polyethylene granuloma. Of great importance is the preservation of the contact of muscles and residual parts of the destructed femoral bone. The short version of the Wagner stem (190 mm and 225 mm) has fully justified itself in revision surgeries of the replacement of the stem in cases of a preserved bone stock. Wagner stem sufficiently bridges the trepanation hole and is safely engaged in the femoral shaft. The long Wagner stem (265 mm and 305 mm) has proved suitable in revision surgeries in cases of thinner cortex and defects in the whole length of the loosened implant. This stem requires a transfemoral approach and a perfect stable anchoring of the stem in the stable skeleton of the femoral shaft. Bone formation and remodelling of proximal femur does not affect the length of the limb. Of great importance is its accurate planning. This procedure is a considerable contribution to the solution of these severe complications.

Based on seven-year experience with non-cemented femoral components of total endoprostheses of the hip joint, type Schenker, the authors assume that their use is limited only to a small group of patients under 40 years of age, provided strict principles as regards precision of implantation are respected. The latter are discussed in the submitted paper.

The authors investigated the intensity of collagen synthesis in patients subjected to operation or re-operation of a total endoprosthesis of the hip joint. The patients suffered from osteoarthritis, rheumatoid arthritis and ankylosing spondylitis. The authors assessed the activity of collagen glucosyl transferase (S-GGT) and the concentration of the N-terminal propeptide procollagen type III by two methods (S-Pro III-N-P and S-Fab) in serum before and after operation. A significant rise of S-GGT and S-Fab, as compared with controls, occurred only after operation while S-Pro III-N-P was elevated already before operation. S-GGT did not differ before and after operation, while N-propeptide concentration rose when either method was used.