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Stem migration and bone density at ten years : a randomized radiostereometry and dual-energy X-ray absorptiometry study on a short uncemented hip stem with and without a collar

Sébastien Daudi, Vasileios Zampelis, Ola Belfrage, G. Flivik

The Bone & Joint Journal, 2025

50 participants

Abstract

Aims

Short, uncemented hip stems might provide a favourable alternative in total hip arthroplasty (THA) by preserving proximal bone mass through reduced strain-adaptive remodelling. We evaluated and compared the migration and periprosthetic bone remodelling of a short stem with and without a collar, using radiostereometric analysis (RSA) to measure implant migration and dual-energy X-ray absorptiometry (DXA) to evaluate periprosthetic bone remodelling. In this study we present ten-year follow-up results, completing previously published two- and five-year RSA and DXA studies.

Methods

A total of 50 patients (34 males) underwent THA due to osteoarthritis and were randomized to either a collared or collarless short stem. Patients were followed for ten years with repeated RSA and DXA examinations. Patient-reported outcome measures (PROMs), Hip disability and Osteoarthritis Outcome Score, EuroQol five-dimension questionnaire, and Forgotten Joint Score were collected.

Results

A total of 45 patients remained at the ten-year follow-up. RSA showed early implant stabilization and osseointegration within three months after an initial subsidence of 0.62 mm (95% CI 0.33 to 0.91) for collared and 0.76 mm (95% CI 0.55 to 0.96) for collarless stems. Minimal further migration was observed up to ten years. Net bone mineral density at ten years was -3.3% (95% CI -9.2 to 2.7) and -2% (95% CI -7.3 to 3.4) in collared and collarless stems, respectively. The presence of a collar did not result in…

How strong is the evidence?

Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design. Reported size: 50 participants or records.

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