Revision arthroplasty for infected hip arthroplasty creates a challenging scenario to surgeons. Either a single stage or more traditionally a two-stage revision is performed. Most surgeons utilise an antibiotic loaded cement spacer, but the implant is often rotationally unstable predisposing to dislocation, acetabular bone loss and fracture of the spacer. Pain and discomfort on mobilisation also often occur. We would like to introduce an alternative approach to this challenging scenario with the use of a two-stage revision with an extended trochanteric osteotomy and loosely cemented hip arthroplasty as the first stage spacer. Surgical Technique: The first stage involves removal of metal ware with all infected tissue and cement performed through an extended trochanteric osteotomy. Circlage wires reduce the osteotomy and a long stem femoral component is inserted with antibiotic infused cement limited to the calcar region. The acetabulum is similarly removed and replaced with a loosely cemented polyethylene liner. The second stage is delayed until the infection is settled and the osteotomy is healed. Removal of the metalware is performed with relative ease, without need for an osteotomy. Reinsertion of an uncemented femoral and acetabular component is then performed. However a second stage is not always required in some patients. We report a single surgeon series comprising 10 patients from December 2003 to June 2007. The most common organism isolated was Staphylococci species. All operations were performed via a posterior approach. 9 patients were clinically assessed and the Harris hip score calculated. All patients were radiologically assessed. Osteotomies healed in all patients. Only 6 patients underwent a second stage and radiographs show good osseous integration of both components. Two patients are awaiting a second stage revision, while the other two are asymptomatic and not interested in undertaking the second stage. No dislocations, bony erosions or reinfection was noted in our series. We recommend this alternative approach to the conventional one or two staged revision arthroplasty. The extended trochanteric ostoetomy ensures rapid and complete removal of all foreign and infected material. The loosely cemented spacer effectively delivers local antibiotic and provides a stable, asymptomatic hip whilst awaiting the second stage, which may not be required.
Moderate to severe acetabular bone loss in revision hip arthroplasty is challenging. Various treatment options are available but the medium to long term results have not been encouraging. The porus tantalum uncemented cup may be used successfully to address moderate to severe bone loss in acetabulum revision surgery. We report a single surgeon series. Between December 2003 and June 2007, 39 patients (43 hips) underwent hip revision surgery. There were 17 men and 23 women with a mean age at surgery of 71.9 years (range 36–96). The mean follow up was 40 months (range 24–66). A porus tantulum modular multi hole uncemented cup was used in all cases. At time of assessment 6 patients had died, 2 patients developed dementia and another 2 patients were not contactable. All 10 patients had no significant clinical or radiological concerns at their last orthopaedic review. The remaining 29 alive patients (33 hips) were available for clinical evaluation. Harris hip score of these 33 hips showed, 24 excellent or good, 7 fair and 2 poor. Radiological results: All 39 patient’s (43 hips) radiographs were reviewed. The acetabular defect was quantified according to Paprosky. Classification taking into account the intra operative findings and pre operative imaging. The horizontal (x-axis), vertical (y-axis) distance from the ipsilateral tear drop and abduction angle were measured in both the pre-operative and post-operative radiographs. According to Paprosky’s classification there were two 2A, ten 2B, six 2C, fourteen 3A and eleven 3B defects. All 43 hips showed good osseous integration. No loosening was noticed in our series. No significant improvement was noticed in the abduction angle and x-axis but significant improvement was noticed in the y-axis indicating more anatomical positioning of the cup within the acetabulum. One deep infection. 2 of the 5 dislocations were recurrent and successfully managed with a constrained liner. We recommend the Porus tantulum uncemented cup as a very useful implant in often very difficult situation. The mechanical properties of the trabecular metal certainly helps to positively encourages osseous integration providing a sound biological fixation and the high co-efficient of friction helps to implant these cup with as little as 30% host bone contact.
