We modified the posterior approach by preserving the external rotator muscles to enhance joint stability after primary THA.
We asked whether this modified posterior approach would have a lower dislocation rate than the conventional posterior approach,
with and without a repair of external rotator muscles. We retrospectively divided 557 patients (670 hips) who had undergone
primary THA into three groups based on how the external rotator muscles had been treated during surgery: (1) not repaired
after sectioning, (2) repaired after sectioning, or (3) not sectioned and preserved. The minimum followup was 1 year. In the
group with preserved external rotator muscles, we observed no dislocations; in comparison, the dislocation rates for the repaired
rotator group and the no-repair group were 3.9% and 5.3%, respectively. This modified posterior approach, which preserves
the short external rotator muscles, seemed effective in preventing early dislocation after primary THA.
Level of Evidence: Level III, therapeutic study. See the Guidelines for Authors for a complete description of levels of evidence.
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Each author certifies that his or her institution has approved the reporting of these cases, that all investigations were
conducted in conformity with ethical principles of research, and that informed consent for participation in the study was
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