Reducing variability in apparent operative inclination during total hip arthroplasty

findings of a randomised controlled trial

Chris O'Neill, Janet Hill, Christopher Patterson, Dennis Molloy, Harinderjit Gill, David Beverland

Research output: Contribution to journalArticle

1 Citation (Scopus)
28 Downloads (Pure)

Abstract

Aims: To determine which of 3 methods of cup insertion most accurately achieved a target apparent operative inclination (AOI) of 35° ± 2.5°: (1) Freehand; (2) Modified Mechanical Alignment Guide (MAG); or (3) Digital Inclinometer assisted. Methods: Using a cementless cup via a posterior approach in lateral decubitus 270 participants were recruited, with 90 randomised to each method. The primary outcome was the unsigned deviation from target AOI. The digital inclinometer was used to measure AOI in all cases, though the surgeon remained blinded to the reading intraoperatively for both the Freehand and MAG methods. Results: Mean deviation from target AOI for the Freehand, Modified 35° MAG and Digital Inclinometer techniques was 2.9°, 1.8° and 1.3° respectively. When comparing mean deviation from target AOI, statistically significant differences between the Freehand / Inclinometer groups (p < 0.001), the Freehand / Modified 35° MAG groups (p < 0.001) and the Digital Inclinometer / Modified 35° MAG groups (p < 0.023) were evident. The Digital Inclinometer technique enabled the surgeon to achieve a target AOI of 35° ± 2.5° in 88% of cases, compared to 71% of Modified 35° MAG cases and only 51% of Freehand cases. Discussion: The Digital Inclinometer and the Modified 35° MAG techniques were both more accurate than the Freehand technique, with the Digital Inclinometer technique proving most accurate overall. Radiographic inclination (RI) is also influenced by operative anteversion; however, the greatest source of error with respect to RI occurs when the pelvic sagittal plane is not horizontal at the time of acetabular component insertion. Clinical Trial Protocol number: NCT01831401.

Original languageEnglish
Pages (from-to)234-239
Number of pages6
JournalHip International
Volume28
Issue number3
DOIs
Publication statusPublished - 1 May 2018

Fingerprint

Arthroplasty
Hip
Randomized Controlled Trials
Translating
Reading

Keywords

  • Acetabular component orientation
  • apparent operative inclination
  • digital inclinometer
  • pelvic sagittal plane
  • total hip arthroplasty

ASJC Scopus subject areas

  • Surgery
  • Orthopedics and Sports Medicine

Cite this

Reducing variability in apparent operative inclination during total hip arthroplasty : findings of a randomised controlled trial. / O'Neill, Chris; Hill, Janet; Patterson, Christopher; Molloy, Dennis; Gill, Harinderjit; Beverland, David.

In: Hip International, Vol. 28, No. 3, 01.05.2018, p. 234-239.

Research output: Contribution to journalArticle

O'Neill, Chris ; Hill, Janet ; Patterson, Christopher ; Molloy, Dennis ; Gill, Harinderjit ; Beverland, David. / Reducing variability in apparent operative inclination during total hip arthroplasty : findings of a randomised controlled trial. In: Hip International. 2018 ; Vol. 28, No. 3. pp. 234-239.
@article{de159f4322684327b7432413eba085f1,
title = "Reducing variability in apparent operative inclination during total hip arthroplasty: findings of a randomised controlled trial",
abstract = "Aims: To determine which of 3 methods of cup insertion most accurately achieved a target apparent operative inclination (AOI) of 35° ± 2.5°: (1) Freehand; (2) Modified Mechanical Alignment Guide (MAG); or (3) Digital Inclinometer assisted. Methods: Using a cementless cup via a posterior approach in lateral decubitus 270 participants were recruited, with 90 randomised to each method. The primary outcome was the unsigned deviation from target AOI. The digital inclinometer was used to measure AOI in all cases, though the surgeon remained blinded to the reading intraoperatively for both the Freehand and MAG methods. Results: Mean deviation from target AOI for the Freehand, Modified 35° MAG and Digital Inclinometer techniques was 2.9°, 1.8° and 1.3° respectively. When comparing mean deviation from target AOI, statistically significant differences between the Freehand / Inclinometer groups (p < 0.001), the Freehand / Modified 35° MAG groups (p < 0.001) and the Digital Inclinometer / Modified 35° MAG groups (p < 0.023) were evident. The Digital Inclinometer technique enabled the surgeon to achieve a target AOI of 35° ± 2.5° in 88{\%} of cases, compared to 71{\%} of Modified 35° MAG cases and only 51{\%} of Freehand cases. Discussion: The Digital Inclinometer and the Modified 35° MAG techniques were both more accurate than the Freehand technique, with the Digital Inclinometer technique proving most accurate overall. Radiographic inclination (RI) is also influenced by operative anteversion; however, the greatest source of error with respect to RI occurs when the pelvic sagittal plane is not horizontal at the time of acetabular component insertion. Clinical Trial Protocol number: NCT01831401.",
keywords = "Acetabular component orientation, apparent operative inclination, digital inclinometer, pelvic sagittal plane, total hip arthroplasty",
author = "Chris O'Neill and Janet Hill and Christopher Patterson and Dennis Molloy and Harinderjit Gill and David Beverland",
year = "2018",
month = "5",
day = "1",
doi = "10.1177/1120700018777485",
language = "English",
volume = "28",
pages = "234--239",
journal = "Hip International",
issn = "1724-6067",
publisher = "Wichtig Publishing",
number = "3",

}

TY - JOUR

T1 - Reducing variability in apparent operative inclination during total hip arthroplasty

T2 - findings of a randomised controlled trial

AU - O'Neill, Chris

AU - Hill, Janet

AU - Patterson, Christopher

AU - Molloy, Dennis

AU - Gill, Harinderjit

AU - Beverland, David

PY - 2018/5/1

Y1 - 2018/5/1

N2 - Aims: To determine which of 3 methods of cup insertion most accurately achieved a target apparent operative inclination (AOI) of 35° ± 2.5°: (1) Freehand; (2) Modified Mechanical Alignment Guide (MAG); or (3) Digital Inclinometer assisted. Methods: Using a cementless cup via a posterior approach in lateral decubitus 270 participants were recruited, with 90 randomised to each method. The primary outcome was the unsigned deviation from target AOI. The digital inclinometer was used to measure AOI in all cases, though the surgeon remained blinded to the reading intraoperatively for both the Freehand and MAG methods. Results: Mean deviation from target AOI for the Freehand, Modified 35° MAG and Digital Inclinometer techniques was 2.9°, 1.8° and 1.3° respectively. When comparing mean deviation from target AOI, statistically significant differences between the Freehand / Inclinometer groups (p < 0.001), the Freehand / Modified 35° MAG groups (p < 0.001) and the Digital Inclinometer / Modified 35° MAG groups (p < 0.023) were evident. The Digital Inclinometer technique enabled the surgeon to achieve a target AOI of 35° ± 2.5° in 88% of cases, compared to 71% of Modified 35° MAG cases and only 51% of Freehand cases. Discussion: The Digital Inclinometer and the Modified 35° MAG techniques were both more accurate than the Freehand technique, with the Digital Inclinometer technique proving most accurate overall. Radiographic inclination (RI) is also influenced by operative anteversion; however, the greatest source of error with respect to RI occurs when the pelvic sagittal plane is not horizontal at the time of acetabular component insertion. Clinical Trial Protocol number: NCT01831401.

AB - Aims: To determine which of 3 methods of cup insertion most accurately achieved a target apparent operative inclination (AOI) of 35° ± 2.5°: (1) Freehand; (2) Modified Mechanical Alignment Guide (MAG); or (3) Digital Inclinometer assisted. Methods: Using a cementless cup via a posterior approach in lateral decubitus 270 participants were recruited, with 90 randomised to each method. The primary outcome was the unsigned deviation from target AOI. The digital inclinometer was used to measure AOI in all cases, though the surgeon remained blinded to the reading intraoperatively for both the Freehand and MAG methods. Results: Mean deviation from target AOI for the Freehand, Modified 35° MAG and Digital Inclinometer techniques was 2.9°, 1.8° and 1.3° respectively. When comparing mean deviation from target AOI, statistically significant differences between the Freehand / Inclinometer groups (p < 0.001), the Freehand / Modified 35° MAG groups (p < 0.001) and the Digital Inclinometer / Modified 35° MAG groups (p < 0.023) were evident. The Digital Inclinometer technique enabled the surgeon to achieve a target AOI of 35° ± 2.5° in 88% of cases, compared to 71% of Modified 35° MAG cases and only 51% of Freehand cases. Discussion: The Digital Inclinometer and the Modified 35° MAG techniques were both more accurate than the Freehand technique, with the Digital Inclinometer technique proving most accurate overall. Radiographic inclination (RI) is also influenced by operative anteversion; however, the greatest source of error with respect to RI occurs when the pelvic sagittal plane is not horizontal at the time of acetabular component insertion. Clinical Trial Protocol number: NCT01831401.

KW - Acetabular component orientation

KW - apparent operative inclination

KW - digital inclinometer

KW - pelvic sagittal plane

KW - total hip arthroplasty

UR - http://www.scopus.com/inward/record.url?scp=85052607074&partnerID=8YFLogxK

U2 - 10.1177/1120700018777485

DO - 10.1177/1120700018777485

M3 - Article

VL - 28

SP - 234

EP - 239

JO - Hip International

JF - Hip International

SN - 1724-6067

IS - 3

ER -