Alireza Moharrami1, Seyed Peyman Mirghaderi1, Nima Hoseini-Zare1, Mohammad Hasan Kaseb2, Seyed Mir Mansour Moazen-Jamshidi3, Ahmed Kareem Mansour1, Seyed Mohammad Javad Mortazavi4. 1. Joint Reconstruction Research Center, Tehran University of Medical Sciences, Tehran, Iran. 2. Knee Surgery Fellowship, Joint Reconstruction Research Center, Tehran University of Medical Sciences, Tehran, Iran. 3. Fellowship of Hip and Pelvic Surgery, Zanjan University of Medical Science, Zanjan, Iran. 4. Joint Reconstruction Research Center, End of Keshavarz Blvd, Imam Khomeini Hospital, Tehran University of Medical Science, Keshavarz Blvd, Tehran, Iran. smjmort@yahoo.com.
Abstract
BACKGROUND: Since femoral and horizontal offsets may be contributing factors to hip and pelvic balance, this study seeks to determine whether there is a correlation between pelvic obliquity (PO) after unilateral total hip arthroplasty (THA) and horizontal/vertical offset differences of the replaced and contralateral natural joints. METHODS: A cross-sectional study was performed on adult patients who underwent unilateral THA between 2017 and 2020. An expert orthopaedic resident measured PO angles and offset parameters. "Delta medial offset" is considered medial offset of the replaced hip minus the medial offset of the contralateral side. "Absolute delta medial offset" is considered the absolute value of the "Delta medial offset." RESULTS: Finally, 133 patients were included in the study with a mean (SD) age of 45.3 ± 14.8 years and 57.9% female. The PO values (median, IQR) changed from 3.2 (1.7-5.7) before THA to 3.0 (1.50-5.6) after THA, not significantly decreased (P = 0.31). The PO after THA is significantly correlated with PO before THA (correlation coefficient of 0.457, P < 0.001), the delta medial offset after THA (correlation coefficient of - 0.24, P = 0.006), and the absolute delta medial offset after THA (correlation coefficient of 0.284, P = 0.001). The amount of changes of delta medial offset, before and after surgery, was not significantly correlated to PO or PO changes after surgery. CONCLUSION: PO before the THA and medial offset discrepancy after THA are two important contributing factors for post-operative PO. Restoring the medial offset of the affected side and lowering the delta medial offset between the two sides can significantly decrease post-operative PO.
BACKGROUND: Since femoral and horizontal offsets may be contributing factors to hip and pelvic balance, this study seeks to determine whether there is a correlation between pelvic obliquity (PO) after unilateral total hip arthroplasty (THA) and horizontal/vertical offset differences of the replaced and contralateral natural joints. METHODS: A cross-sectional study was performed on adult patients who underwent unilateral THA between 2017 and 2020. An expert orthopaedic resident measured PO angles and offset parameters. "Delta medial offset" is considered medial offset of the replaced hip minus the medial offset of the contralateral side. "Absolute delta medial offset" is considered the absolute value of the "Delta medial offset." RESULTS: Finally, 133 patients were included in the study with a mean (SD) age of 45.3 ± 14.8 years and 57.9% female. The PO values (median, IQR) changed from 3.2 (1.7-5.7) before THA to 3.0 (1.50-5.6) after THA, not significantly decreased (P = 0.31). The PO after THA is significantly correlated with PO before THA (correlation coefficient of 0.457, P < 0.001), the delta medial offset after THA (correlation coefficient of - 0.24, P = 0.006), and the absolute delta medial offset after THA (correlation coefficient of 0.284, P = 0.001). The amount of changes of delta medial offset, before and after surgery, was not significantly correlated to PO or PO changes after surgery. CONCLUSION: PO before the THA and medial offset discrepancy after THA are two important contributing factors for post-operative PO. Restoring the medial offset of the affected side and lowering the delta medial offset between the two sides can significantly decrease post-operative PO.
Authors: Michael S Madsen; Merrill A Ritter; Harold H Morris; John B Meding; Michael E Berend; Phillip M Faris; Vassilios G Vardaxis Journal: J Orthop Res Date: 2004-01 Impact factor: 3.494