Revision total hip arthroplasty using a cementless tapered revision stem in patients with a mean age of 82 years

Distal fixation stems for revision of total hip replacement

The purpose of this study was to retrospectively assess patients treated with modular, non-cemented, tapered, fluted, distal fixation stems. We included patients with 24 months mínimum follow-up. Diagnosis that led to revisions were described. The radiographic analysis was made with preoperative, immediate postoperative and last control postoperative X-rays. Sixty-seven patients met inclusion criteria. We observed 59,7% (n=40) Osteointegration, 34,3% of Stable Fibrosis and 5,97% Unstable fibrosis. Stress Shielding was registered with 10,44% and Subsidence was observed in 34,3% of the patients. Modular, fluted, tapered, distal fixation stems have an excellent survival rates.

Proximal Femoral Bone Regeneration After an Uncemented Hydroxyapatite-coated Long-stem in Revision Hip Surgery

Background:

Bone remodelling with lateral femoral cortex thinning is a major concern after extensively porous-coated long-stem in revision surgery. Extensive hydroxyapatite coated long-stems were introduced to improve osseointegration, but bone remodelling changes have not been quantified.

Objective:

The question of whether bone remodelling changes from extensive hydroxyapatite-coated long stems influence the durability of femoral revision, clinical outcome is assessed in follow-up radiographs.

Methods:

Uncemented straight monoblock hydroxyapatite-coated long-stems used in revision hip surgery for aseptic loosening were assessed in a consecutive series of 64 hips (60 patients). Mean follow-up was 8.6 years and the mean age at surgery was 70 years (27-91). The pre-operative bone defect was classified according to Paprosky. Cortical struts were not used in this series. Cortical index and femoral cortical width were measured at three different levels at different periods.

Results:

Four patients with pain under level 4 due to stem loosening needed an exchange surgery of their femoral component, but two patients rejected re-surgery. The cumulative probability of not having aseptic loosening was 91.2% (95% confidence interval 73.5-96.9) at 10 years according to Kaplan and Meier. Twenty-seven of 35 osteolytic lesions had disappeared or decreased at the last follow-up. The thickness of the lateral and medial cortex increased over the course of the study at different levels. Increases of femoral cortex thickness were greater in men and in cases with mild bone defects.

Conclusion:

Although clinical outcome of the hydroxyapatite-coated long stem in revision surgery is good but not outstanding, most osteolytic lesions heal and the femoral cortex thickness increases at different levels.

Supercharging irradiated allografts with mesenchymal stem cells improves acetabular bone grafting in revision arthroplasty

PURPOSE

The procedure of bone allografting associated with a reinforcement device is widely used for acetabulum revision. However in absence of biologic fixation of the allograft, failure of the reconstruction may occur. We made the hypothesis that it would be possible to load these grafts with bone marrow derived mesenchymal stem cells (MSC) to rescue the osteogenic capacity of an allogenic dead bone and therefore enhance incorporation of allografts with the host bone and decrease the number of failures related to the allograft.

METHOD

We identified 60 patients who had undergone acetabular component revision for aseptic failure of cemented implants associated with massive periacetabular osteolysis and Paprosky type 3A or 3B classification (without pelvic discontinuity) between 1996 and 2001. The study group of 30 patients received MSCs in the allograft and at the host graft junction. The average total number of MSCs received by each patient was 195,000 cells (range 86,000-254,000 cells). The control group of 30 patients had no MSCs in the allograft. Patients were matched for the size of periacetabular osteolysis (Paprosky type 3A or 3B). We compared the evolution of the allografts and evaluated cup migration and revision of the hips as end points at a minimum of 12 years or until failure.

RESULT

Better radiographic graft union rates and less allograft resorption were observed with allografts loaded with stem cells. Allograft resorption was significantly decreased in the group with allograft loaded with MSCs (1.2 cm(2) -range 0-2.3 cm(2)-of resorption on radiographs in the group with MSCs; versus 6 cm(2), range 2.1-8.5 cm(2) in the group without MSCs). The rate of mechanical failure was highest (p = 0.01) among the 30 patients with allograft without stem cells (9/30; 30 %) compared with no failures for patients with allograft loaded with stem cells. Revision of the cup was necessary in nine patients in the control group. No revision was performed in the 30 patients of the study group with MSCs.

CONCLUSION

For acetabular defect reconstruction, loading the allograft with MSCs has resulted in a lower rate of failure as compared with allograft without MSCs.

Systematic review on outcomes of acetabular revisions with highly-porous metals

PURPOSE

The purpose of this study was to systematically review the literature and report the clinical and radiographic outcomes of highly-porous acetabular cups in revision settings.

METHOD

A literature search of four electronic databases of EMBASE, CINAHL-plus, PubMed, and SCOPUS yielded 25 studies reporting the outcomes of 2,083 revision procedures with highly-porous acetabular components. There was lack of high quality evidence (level I and level II studies) and only two studies with level III evidence, while the remainder were all level IV studies. In addition, a majority of the studies had small sample sizes and had short to mid-term follow-up. The mean age of the patients was 65 years (range, 58-72 years) and the mean follow-up was 3.6 years (range, two to six years). Outcomes evaluated were aseptic survivorship, Harris hip scores, migration rates, incidence of peri-acetabular radiolucencies and radiographic restoration of the hip centre.

RESULTS

The mean aseptic survivorship was 97.2% (range, 80-100%). The Harris hip scores improved from a mean pre-operative score of 42 points, (range, 29-75 points), to a mean postoperative score of 79 points (range, 69-94 points). The mean incidence of cup migration and prevalence of peri-acetabular radiolucencies was 2.4% (range, 0-8.8%) and 4.6% (range, 0-19%), respectively, at final follow-up. The vertical hip centre-of-rotation was restored significantly from a mean of 39.2 mm (range, 27.6-50 mm) pre-operatively, to a mean of 24.1 mm (range, 7.4-47 mm), postoperatively.

CONCLUSION

The short-term clinical and radiographic results of highly-porous metals in revision hip arthroplasty are excellent with a low rate of loosening in the presence of both major and minor bone loss.