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Large femoral bone loss after hip revision using the uncemented proximally porous-coated Bi-Metric prosthesis: 22 hips followed for a mean of 6 years.

Adolphson PY, Salemyr MO, Sköldenberg OG, Bodén HS - Acta Orthop (2009)

Bottom Line: Osteolysis seen at revision had diminished in 19 of the 22 hips at follow-up.We noted a large reduction in bone mineral density.It was most pronounced in Gruen regions 1, 2, 6, and 7.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Sciences at Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden. per.adolphson@ds.se

ABSTRACT

Background and purpose: Periprosthetic bone loss after uncemented femoral hip revision is a matter of concern. We have used a proximally porous- and hydroxyapatite-coated prosthesis (Bi-Metric) in revision since 1989 and now we report the bone changes. This prosthesis is intended to distribute the forces more evenly and to avoid proximal femoral unloading.

Methods: 22 patients were unilaterally reoperated because of aseptic loosening. Only patients with a healthy contralateral hip were included. Mean age at revision was 69 (55-80) years. Bone defects were graded by Gustilo-Pasternak and Endo-Klinik classifications. Clinical assessment was performed with Harris hip score. We used radiographs and dual-energy X-ray absorptiometry to evaluate migration, femoral remodeling, and bone mineral density after 72 (30-158) months.

Results: The mean Harris hip score was 74 (30-100) points at follow-up. Mild thigh discomfort was present in 1 patient and moderate thigh pain in 3 patients. There was no loosening or subsidence. Osteolysis seen at revision had diminished in 19 of the 22 hips at follow-up. We noted a large reduction in bone mineral density. It was most pronounced in Gruen regions 1, 2, 6, and 7.

Interpretation: Revision with this stem is a reliable procedure; however, we noted a large degree of proximal bone loss that could lead to later mechanical complications or fractures.

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The proximally hydroxyapatite-coated Bi-Metric modular femoral stem. The prosthesis is tapered in 3 dimensions.
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Figure 0001: The proximally hydroxyapatite-coated Bi-Metric modular femoral stem. The prosthesis is tapered in 3 dimensions.

Mentions: Mean age at revision was 69 (55–80) years and the mean follow-up time was 6 (2.5–13) years. The index diagnosis was primary osteoarthritis in all patients. 16 patients had had only 1 hip arthroplasty in the same hip before the revision, 4 patients had had 2 previous arthroplasties, and 2 patients had undergone 3 earlier arthroplasties. Mean time between the primary hip arthroplasty and our revision was 6 (1–13) years. The patients were reoperated with an uncemented prosthesis: the Bi-Metric femoral stem (Biomet Inc., Warsaw, IN) (Figure 1). It is a collarless, tapered stem (3º) made of titanium alloy, where the proximal 30% of the stem has a porous-coated (100–200 µm) surface with a plasma-sprayed HA layer (thickness 40–70 µm, crystallinity 50–70%, purity > 95%). The distal 70% has a textured surface with a roughness of 6.9 µm. It has incremental sizing from 7–19 mm in diameter, has a proportional increase in length from 115 to 175 mm, and has a modular head of cobalt chrome. All patients were reoperated through a posterior approach. 19 of the revised stems were cemented. Bone grafting around the proximal part of the stem was simultaneously carried out with small amounts of autologous bone (11 hips) and homologous bone (2 hips). 11 patients underwent a simultaneous cup exchange at revision, and 2 later cup revisions were also done. The patients received either a cemented polyethylene cup (8 patients) or an uncemented hydroxyapatite-coated cup with a polyethylene liner (5 patients). The patients were mobilized on the day after the operation under supervision of a physiotherapist. Postoperative weight bearing was individualized according to the surgeon's preference. Some patients were recommended protected weight bearing for up to 3 months.


Large femoral bone loss after hip revision using the uncemented proximally porous-coated Bi-Metric prosthesis: 22 hips followed for a mean of 6 years.

Adolphson PY, Salemyr MO, Sköldenberg OG, Bodén HS - Acta Orthop (2009)

The proximally hydroxyapatite-coated Bi-Metric modular femoral stem. The prosthesis is tapered in 3 dimensions.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2823225&req=5

Figure 0001: The proximally hydroxyapatite-coated Bi-Metric modular femoral stem. The prosthesis is tapered in 3 dimensions.
Mentions: Mean age at revision was 69 (55–80) years and the mean follow-up time was 6 (2.5–13) years. The index diagnosis was primary osteoarthritis in all patients. 16 patients had had only 1 hip arthroplasty in the same hip before the revision, 4 patients had had 2 previous arthroplasties, and 2 patients had undergone 3 earlier arthroplasties. Mean time between the primary hip arthroplasty and our revision was 6 (1–13) years. The patients were reoperated with an uncemented prosthesis: the Bi-Metric femoral stem (Biomet Inc., Warsaw, IN) (Figure 1). It is a collarless, tapered stem (3º) made of titanium alloy, where the proximal 30% of the stem has a porous-coated (100–200 µm) surface with a plasma-sprayed HA layer (thickness 40–70 µm, crystallinity 50–70%, purity > 95%). The distal 70% has a textured surface with a roughness of 6.9 µm. It has incremental sizing from 7–19 mm in diameter, has a proportional increase in length from 115 to 175 mm, and has a modular head of cobalt chrome. All patients were reoperated through a posterior approach. 19 of the revised stems were cemented. Bone grafting around the proximal part of the stem was simultaneously carried out with small amounts of autologous bone (11 hips) and homologous bone (2 hips). 11 patients underwent a simultaneous cup exchange at revision, and 2 later cup revisions were also done. The patients received either a cemented polyethylene cup (8 patients) or an uncemented hydroxyapatite-coated cup with a polyethylene liner (5 patients). The patients were mobilized on the day after the operation under supervision of a physiotherapist. Postoperative weight bearing was individualized according to the surgeon's preference. Some patients were recommended protected weight bearing for up to 3 months.

Bottom Line: Osteolysis seen at revision had diminished in 19 of the 22 hips at follow-up.We noted a large reduction in bone mineral density.It was most pronounced in Gruen regions 1, 2, 6, and 7.

View Article: PubMed Central - PubMed

Affiliation: Department of Clinical Sciences at Danderyd Hospital, Karolinska Institutet, Stockholm, Sweden. per.adolphson@ds.se

ABSTRACT

Background and purpose: Periprosthetic bone loss after uncemented femoral hip revision is a matter of concern. We have used a proximally porous- and hydroxyapatite-coated prosthesis (Bi-Metric) in revision since 1989 and now we report the bone changes. This prosthesis is intended to distribute the forces more evenly and to avoid proximal femoral unloading.

Methods: 22 patients were unilaterally reoperated because of aseptic loosening. Only patients with a healthy contralateral hip were included. Mean age at revision was 69 (55-80) years. Bone defects were graded by Gustilo-Pasternak and Endo-Klinik classifications. Clinical assessment was performed with Harris hip score. We used radiographs and dual-energy X-ray absorptiometry to evaluate migration, femoral remodeling, and bone mineral density after 72 (30-158) months.

Results: The mean Harris hip score was 74 (30-100) points at follow-up. Mild thigh discomfort was present in 1 patient and moderate thigh pain in 3 patients. There was no loosening or subsidence. Osteolysis seen at revision had diminished in 19 of the 22 hips at follow-up. We noted a large reduction in bone mineral density. It was most pronounced in Gruen regions 1, 2, 6, and 7.

Interpretation: Revision with this stem is a reliable procedure; however, we noted a large degree of proximal bone loss that could lead to later mechanical complications or fractures.

Show MeSH
Related in: MedlinePlus