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No medium-term advantage of electrochemical deposition of hydroxyapatite in cementless femoral stems. 5-year RSA and DXA results from a randomized controlled trial.

Flatøy B, Röhrl SM, Bøe B, Nordsletten L - Acta Orthop (2015)

Bottom Line: Bone resorption occurred mainly during the first year, and subsequently decreased to a rate close to what is seen in normal ageing.The greatest total decrease occurred in Gruen zones 1 and 7, similar in the groups at 5 years.Thus, at this point, Bonemaster appears to be safe.

View Article: PubMed Central - PubMed

Affiliation: a Department of Orthopedic Surgery , Oslo University Hospital Ullevål , Oslo , Norway .

ABSTRACT

Background and purpose: Hydroxyapatite has been used for a long time as an adjunct to enhance cementless fixation. The benefit of this is still debated, but new methods of hydroxyapatite deposition have emerged, offering possible gains. In order to investigate this further, we compared the migration pattern and periprosthetic bone remodeling in a cementless femoral stem with either electrochemically deposited hydroxyapatite-called Bonemaster (BM)-or a conventional plasma-sprayed hydroxyapatite (HA) coating.

Patients and methods: 55 hips were randomized to either BM or HA cementless femoral stems. Patients were followed with radiostereometry (RSA), dual-energy X-ray absorptiometry (DXA), radiographic measurements, and hip questionnaires for 5 years.

Results: For both stems, migration occurred mainly as subsidence and retroversion during the first 3 months. The BM group had a higher retroversion rate of 0.17° per month during this period, as compared to 0.06° per month for the HA group (p = 0.006). Thereafter, there was almost no movement in any direction for both stem types. Bone resorption occurred mainly during the first year, and subsequently decreased to a rate close to what is seen in normal ageing. The greatest total decrease occurred in Gruen zones 1 and 7, similar in the groups at 5 years. There was a slightly higher resorption rate in Gruen zone 7 from 2 to 5 years in the BM group (1.3% per year; p = 0.04), but in a magnitude that would scarcely affect stem stability or survival.

Interpretation: There were no clinically relevant differences between the 2 stems regarding stability or periprosthetic bone loss at 5 years. Electrochemically deposited HA does not appear to affect fixation or bone remodeling when compared to conventional plasma spraying at 5 years. Thus, at this point, Bonemaster appears to be safe.

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BMD difference from the postoperative scans in Gruen zone 1 and 7.
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Figure 0004: BMD difference from the postoperative scans in Gruen zone 1 and 7.

Mentions: Precision, measured for all densitometers in all ROIs, ranged from 0.5 to 5.8 (CV) (Boe et al. 2011). Periprosthetic BMD declined in all Gruen zones. The greater part of this bone loss occurred during the first year. At 2 years, we reported a uniform bone loss in Gruen zones 2–7 for both groups, which ranged from 8% to 14% in zones 2–6 and approximately 30% in Gruen zone 7. A difference in statistical significance was, however, found in Gruen zone 1, being 13% in the BM group as compared to 21% in the HA group. From 2 to 5 years, the bone remodeling rate decreased to a rate close to what we see in normal ageing (Hannan et al. 2000). The greatest decrease occurred in Gruen zone 7 (34% for BM and 31% for HA) and 1 (20% for BM and 25% for HA) (Table 1 and Figure 3). There were no statistically significant differences between groups regarding the total decrease in any zone at 5 years, but we did find a statistically significant difference in remodeling rate between 2 and 5 years in Gruen zone 7. BMD in the BM group decreased by 0.11% per month (CI: −0.19 to −0.04) whereas in the HA group it increased by 0.01% per month (CI: −0.08 to 0.1; p = 0.04) (Figure 4 and Table 1).


No medium-term advantage of electrochemical deposition of hydroxyapatite in cementless femoral stems. 5-year RSA and DXA results from a randomized controlled trial.

Flatøy B, Röhrl SM, Bøe B, Nordsletten L - Acta Orthop (2015)

BMD difference from the postoperative scans in Gruen zone 1 and 7.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4940590&req=5

Figure 0004: BMD difference from the postoperative scans in Gruen zone 1 and 7.
Mentions: Precision, measured for all densitometers in all ROIs, ranged from 0.5 to 5.8 (CV) (Boe et al. 2011). Periprosthetic BMD declined in all Gruen zones. The greater part of this bone loss occurred during the first year. At 2 years, we reported a uniform bone loss in Gruen zones 2–7 for both groups, which ranged from 8% to 14% in zones 2–6 and approximately 30% in Gruen zone 7. A difference in statistical significance was, however, found in Gruen zone 1, being 13% in the BM group as compared to 21% in the HA group. From 2 to 5 years, the bone remodeling rate decreased to a rate close to what we see in normal ageing (Hannan et al. 2000). The greatest decrease occurred in Gruen zone 7 (34% for BM and 31% for HA) and 1 (20% for BM and 25% for HA) (Table 1 and Figure 3). There were no statistically significant differences between groups regarding the total decrease in any zone at 5 years, but we did find a statistically significant difference in remodeling rate between 2 and 5 years in Gruen zone 7. BMD in the BM group decreased by 0.11% per month (CI: −0.19 to −0.04) whereas in the HA group it increased by 0.01% per month (CI: −0.08 to 0.1; p = 0.04) (Figure 4 and Table 1).

Bottom Line: Bone resorption occurred mainly during the first year, and subsequently decreased to a rate close to what is seen in normal ageing.The greatest total decrease occurred in Gruen zones 1 and 7, similar in the groups at 5 years.Thus, at this point, Bonemaster appears to be safe.

View Article: PubMed Central - PubMed

Affiliation: a Department of Orthopedic Surgery , Oslo University Hospital Ullevål , Oslo , Norway .

ABSTRACT

Background and purpose: Hydroxyapatite has been used for a long time as an adjunct to enhance cementless fixation. The benefit of this is still debated, but new methods of hydroxyapatite deposition have emerged, offering possible gains. In order to investigate this further, we compared the migration pattern and periprosthetic bone remodeling in a cementless femoral stem with either electrochemically deposited hydroxyapatite-called Bonemaster (BM)-or a conventional plasma-sprayed hydroxyapatite (HA) coating.

Patients and methods: 55 hips were randomized to either BM or HA cementless femoral stems. Patients were followed with radiostereometry (RSA), dual-energy X-ray absorptiometry (DXA), radiographic measurements, and hip questionnaires for 5 years.

Results: For both stems, migration occurred mainly as subsidence and retroversion during the first 3 months. The BM group had a higher retroversion rate of 0.17° per month during this period, as compared to 0.06° per month for the HA group (p = 0.006). Thereafter, there was almost no movement in any direction for both stem types. Bone resorption occurred mainly during the first year, and subsequently decreased to a rate close to what is seen in normal ageing. The greatest total decrease occurred in Gruen zones 1 and 7, similar in the groups at 5 years. There was a slightly higher resorption rate in Gruen zone 7 from 2 to 5 years in the BM group (1.3% per year; p = 0.04), but in a magnitude that would scarcely affect stem stability or survival.

Interpretation: There were no clinically relevant differences between the 2 stems regarding stability or periprosthetic bone loss at 5 years. Electrochemically deposited HA does not appear to affect fixation or bone remodeling when compared to conventional plasma spraying at 5 years. Thus, at this point, Bonemaster appears to be safe.

Show MeSH
Related in: MedlinePlus