Loosened hip joint prosthesis - decision options

— For the period 2013-2015, 36 patients underwent revision surgery because of secondary developed complications after primary hip joint replacement surgery. 14 of them were male and 23 – female, with average age 73 years. Initially 33 patients suffered from hip joint osteoarthritis and the others 3 underwent hip joint replacement after fracture. We examined 4 groups of patients depends on the complications type: - Aseptic loosening in 23 patients, appeared 10 years’ average following primary hip prosthesis surgery. - Septic loosening in 2 patients revealed on second to the tenth month post operatively. In two other patients we observed infected hematoma. - Hip joint prosthesis (luxation) because of trauma or extremely wrong motion we notice in 5 patients. In one of them we revealed acetabular cup malposition. - Periprosthetic fractures with aseptic loosening in 3 patients. All 36 patients had primary cemented hip joint prosthesis. In the first group depends on which prosthesis parts were loosened we did acetabular cup and femoral stem replacement in 15 patients, only acetabular cup replacement in 4 patients and in 3 patients only femoral stem replacement. In 2 patients from second group we replaced the primary prosthesis by total spacer for 8 months followed by revision prosthesis surgery. In 2 haematoma patients we performed debridement, lavage-drainage and long term antibiotic treatment. In 2 patients of third group we replaced the primary head with a longer one and in 3 other patients we replaced the primary acetabular cup by shoulder collar cemented cup. In 2 patients of fourth group we replaced the primary acetabular cup and femoral stem by shoulder collar cemented cup and by revisionary stem delivered by Implant and Zimmer (Revitan). In the third patient we implanted revisionary femoral stem (Implant). 3 years after revisionary hip joint prosthesis surgery we monitor good prosthesis stability and good functional scores.


Introduction
Hip arthroplasty, introduced by Sir John Charnley in the 1960s, is one of the most successful surgical interventions.Notably, the technique was accepted as the surgery of the 20th century.However, different problems and complications have been reported and a revision surgery needs 1 .
Revision of the hip arthroplasty is a complex procedure that poses several challenges for the arthroplasty surgeon: bone loss, removal of the previous implant and cement mantle without inducing additional bone destruction.The surgeon encounters altered and sclerotic bone, unable to support the revision component.Various options for revising have been described in the literature: reinforcement cage Burch-Schneider with bone grafting, long stem with cement fixation, cement fixation and impaction arthroplasty, proximal femoral replacement with a tumor prosthesis or massive allograft, and cementless fixation with distal stem anchorage 1 .
The goals of the current article are: • To outline the main challenges in revision hip arthroplasty.

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To present some characteristics of preoperative planning.• Share our experience with revision hip arthroplasty by presenting some of our clinical cases.

Materials and Methods
A group of 36 patient underwent revision hip arthropalsty in the years between 2013-2015.14 males, 22 females, average age 73.Indication for primary hip arthropalsty was osteoarthritis in 33 patients and fracture of the femoral neck in 3 patients.
Acetabular bone defects are assessed by the Paprovski classification 2 and the periprostetic fractures are classified according to the Vancouver Classification 3 .General perioperative risk is assessed by ASA classification 4 .The results are measured using Oswestry Disability Index (ODI) 5 and Visual Analogue Scale (VAS) 6 .
Anterolateral approach extended distally with or without extended trochanteric osteotomy is used in all cases.Implant used are: standard cemented stems, modular tapered stems, reinforcement cage Burch-Schneider as well as long cemented stems.

Results
Patients are divided into 4 groups according to the type of loosening: I. Aseptic loosening -23 patients.Reinforcement cage is used in acetabulum defect Paprovski 2nd and 3rd degree 7,8 .If needed bone grafting is performed with structural allograft or cancellous bone from tissue bank.Long stems are used in cases with severe proximal femur bone loss or after extended trochanteric osteotomy (Fig. 1).
Dislocations occur in variable postoperative term.Different causes for dislocation are found: insufficient offset, malposition, stem subsidence 9,10 (Fig. 2).One partial and 2 complete revisions are made.Long tapered stems are used with distal to the fracture fixation 11 (Fig. 3).In cases with suspected infection, a quick PJI test is performed.Preferred treatment option for septic loosening is the two stage revision with antibiotic spacer for 4-6 mounts.Long tapered stems as well as standard stems are used, together with reinforcement ring if necessary (Fig. 4).ODI test done on the 2nd postoperative mount shows prevailing number of patients with minimal difficulties performing activities of daily life, which is reported as good clinical outcome.Postoperative follow-up is at 6 and 12 postoperative mounts.

Discussion and Conclusion
Aseptic loosening is the most common cause for revision hip arthroplasty.Reinforcement cage is used in acetabulum defect Paprovski 2nd and 3rd degree.In Paprovski 3A and 3B a structural allograft is used.Extended trochanteric osteotomy is reliable approach when using long femoral stems.In cases with late periprostetic joint infections two stage revision has the highest success rate.

Figure 1 .
Figure 1.Reinforcement cage with bone grafting and long tapered stem.

Figure 3 .
Figure 3. Partial revision with long cemented stem.

Figure 4 .
Figure 4. Two stage revision with custom made antibiotic-loaded spacer.