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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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Y-translation. Individual curves for each stem in both groups.
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Figure 0005: Y-translation. Individual curves for each stem in both groups.

Mentions: Both stems mainly migrated by subsidence and retroversion. Migrations in other directions were minuscule and below the respective precision limit. Subsidence occurred almost exclusively during the first 3 months, with equal slopes in both groups (p = 0.6). After that, there was hardly any subsidence, with no statistically significant differences between groups (p = 0.4) (Table 2 and Figure 4). 1 stem in the BM group showed excessive subsidence of 10.4 mm during the first 3 months, but it remained completely stable during the remaining observation period. The same pattern of movement was seen for retroversion, but the rate was higher during the first 3 months in the BM group: 0.17° per month (CI: 0.11–0.23) as compared to 0.06° per month (CI: −0.01 to 0.12) in the HA group (p = 0.006). From then on, both groups appeared to remain stable, without any differences in the slope between 2 and 5 years (p = 0.3) (Figure 5 and Table 2).


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)

Y-translation. Individual curves for each stem in both groups.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

Figure 0005: Y-translation. Individual curves for each stem in both groups.
Mentions: Both stems mainly migrated by subsidence and retroversion. Migrations in other directions were minuscule and below the respective precision limit. Subsidence occurred almost exclusively during the first 3 months, with equal slopes in both groups (p = 0.6). After that, there was hardly any subsidence, with no statistically significant differences between groups (p = 0.4) (Table 2 and Figure 4). 1 stem in the BM group showed excessive subsidence of 10.4 mm during the first 3 months, but it remained completely stable during the remaining observation period. The same pattern of movement was seen for retroversion, but the rate was higher during the first 3 months in the BM group: 0.17° per month (CI: 0.11–0.23) as compared to 0.06° per month (CI: −0.01 to 0.12) in the HA group (p = 0.006). From then on, both groups appeared to remain stable, without any differences in the slope between 2 and 5 years (p = 0.3) (Figure 5 and Table 2).

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