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Research Article

A stature-specific concept for uncemented, primary total hip arthroplasty

10-year results in 155 patients using two stem shapes and modular necks

, , , , &
Pages 126-133 | Received 11 Nov 2008, Accepted 17 Jul 2009, Published online: 10 Feb 2010
 

Abstract

Background and purpose Variations in hip anatomy limit the femoral canal fit of standard uncemented hip stems. In addition, there are still issues with leg length discrepancy and offset reconstruction, potentially resulting in impingement, dislocation, and wear. Modular stems with different shapes for femoral canal fit and multiple neck options may improve the outcome and reduce complications.

Patients and methods 173 patients (190 hips) received an uncemented THA with 1 of 2 different stem shapes for canal fit and a modular neck for stature-specific hip reconstruction. Median follow-up time was 9 (7–13) years. During the follow-up period, 20 patients died (22 hips) and 12 patients (13 hips) were lost to follow-up. 155 hips were available for evaluation, including clinical and radiological outcome.

Results 1 stem was revised for a periprosthetic fracture following trauma; 10 cups and 2 modular necks were revised (1 for breakage and 1 during cup revision). At 10 years, stem survival was 100%, modular neck survival was 99% (CI: 95–100), and cup survival was 94% (CI: 87–97). No leg length discrepancies were measured in 96% of cases. Offset with anatomic lateralization was achieved in 98%. Median Harris hip score was 94 (47–100) and median Merle d'Aubigné score was 16 (10–18). Relevant radiolucent lines and osteolysis were not found.

Interpretation The uncemented modular neck, dual-stem system used in this series allows accurate reconstruction of the joint by adapting the implant to the needs of the patient. This may improve the outcome of primary THA, which is supported by the results of this medium-term follow-up evaluation.

Acknowledgments

GO: writing of the manuscript and planning and execution of the study. HU and KK: planning and execution of the study and collection of the data. AJ: statistical analysis and interpretation of the data. GA: contributed to planning of the study and data interpretation, and performed parts of the operations. PA: writing of the manuscript and planning, execution, and coordination of the study.

Funding was received from Wright Medical Technology Inc. to support this study. The sponsor took no part in conducting the study or in reporting the results.