Migration analysis of a metaphyseal-anchored short femoral stem in cementless THA and factors affecting the stem subsidence.

Schaer, Michael O.; Finsterwald, Michael; Holweg, Iris; Dimitriou, Dimitris; Antoniadis, Alexander; Helmy, Naeder (2019). Migration analysis of a metaphyseal-anchored short femoral stem in cementless THA and factors affecting the stem subsidence. BMC musculoskeletal disorders, 20(1), p. 604. BioMed Central 10.1186/s12891-019-2980-7

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BACKGROUND

Early femoral stem subsidence following a cementless THA is correlated with aseptic loosening of the femoral component. The short femoral stems allow bone sparing and implantation through a minimally invasive approach; however, due to their metaphyseal anchoring, they might demonstrate different subsidence pattern than the conventional stems.

METHODS

In this prospective single-center study, a total of 68 consecutive patients with an average age of 63 years, and a minimum follow-up of 5 years following a cementless THA with a metaphyseal-anchored short femoral stem were included. The femoral stem subsidence was evaluated using "Ein Bild Roentgen Analyse" (EBRA).

RESULTS

Average stem migration was 0.96 +/- 0.76 mm at 3 months, 1.71 +/- 1.26 mm at 24 months, and 2.04+/- 1.42 mm at last follow-up 60 months postoperative. The only factor that affected migration was a stem size of 6 or more (r2 = 5.74; p = 0.039). Subdivision analysis revealed, that only in females migration appeared to be affected by stem size irrespective of weight but not in men (female stem size of 6 or more vs. less (Difference = - 1.48 mm, R2 = 37.5; p = 0.001). Migration did not have an impact on clinical outcome measures.

CONCLUSIONS

The examined metaphyseal-anchored short femoral stem showed the highest subsidence within the first 3 months postoperative, the implant began to stabilize at about 24 months but continued to slowly migrate with average total subsidence of 2.04 mm at 5 years following the THA. The amount of stem subsidence was not associated with worse clinical outcomes such as HHS, patient satisfaction, or pain.

Item Type:

Journal Article (Original Article)

Division/Institute:

04 Faculty of Medicine > Department of Orthopaedic, Plastic and Hand Surgery (DOPH) > Clinic of Orthopaedic Surgery

UniBE Contributor:

Schär, Michael

Subjects:

600 Technology > 610 Medicine & health

ISSN:

1471-2474

Publisher:

BioMed Central

Language:

English

Submitter:

Kathrin Aeschlimann

Date Deposited:

12 Feb 2020 10:31

Last Modified:

28 Nov 2020 02:30

Publisher DOI:

10.1186/s12891-019-2980-7

PubMed ID:

31831070

Uncontrolled Keywords:

Cementless short-stem EBRA Migration Short-stem hip implant Subsidence

BORIS DOI:

10.7892/boris.138905

URI:

https://boris.unibe.ch/id/eprint/138905

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