IMPACT OF CAPUT-COLLUM-DIAPHYSEAL ANGLE ON FEMORAL STEM POSITIONING IN SHORT-STEM HIP ARTHROPLASTY PERFORMED WITH AN ANTERIOR MINIMALLY INVASIVE SURGERY

P. Antinolfi¹ , L. Giorgini¹ , G. Ancillai¹, L. Lucchetta¹ , F. Manfreda¹ , A. Caraffa¹

¹ Orthopedic and Traumatology Clinic, S. Maria della Misericordia Hospital, Perugia, Italy

Correspondence to:

Journal of Orthopedics 2024 September-December; 16(3): 102-107

Received: 6 October 2024 Accepted: 23 November 2024

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Abstract

This study examines how variations in the Caput-Collum-Diaphyseal (CCD) angle impact femoral stem alignment in total hip arthroplasty (THA) using short stems in the anterior minimally invasive surgery (AMIS). The objective of this study is to evaluate whether native CCD angles in the varus or the valgus influence the postoperative stem alignment, especially deviations greater than 3°, which may affect clinical outcomes. Patients who underwent THA between July 2021 and July 2023 with primary hip osteoarthritis or avascular necrosis were included. Exclusion criteria were postoperative complications, reoperations, or missing radiographs. Postoperative CCD and stem alignment were measured from radiographs, and statistical analyses were performed to compare these variables using t-tests and Pearson’s correlation. Of the 46 hips, 24 were in Group A, and 22 in Group B. Group B showed a better ability to restore the CCD angle (p < 0.05). Both groups demonstrated a significant Pearson correlation between native CCD and postoperative stem alignment (Group A: r -0.60;p < 0.001 and Group B r: 0.486;p < 0.05). The average deviation in stem alignment remained within 3° for both groups. Patients with a varus CCD angle were more likely to have the stem positioned in the varus, while those with a valgus CCD angle showed a slight tendency toward valgus stem alignment. Surgeons should carefully consider preoperative CCD angles to minimize malpositioning during AMIS procedures.

Keywords: AMIS, anterior minimally invasive surgery, Caput-Collum-Diaphyseal angle, CCD, stem alignment, THA, total hip arthroplasty