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NCT Number: NCT01831401

A Study Investigating the Effect of Patient Pelvic Positioning and Method of Acetabular Component Insertion on Acetabular Component Inclination During Total Hip Arthroplasty (THA)

Total Hip Arthroplasty (THA) is one of the most commonly performed orthopaedic operations worldwide. The main aim is overall improvement in levels of patient pain and mobility. Such surgery involves implantation of both an acetabular and femoral component. With the patient in the lateral decubitus position, the Orthopaedic Surgeon assumes that the pelvis is in a neutral position with respect to all three body planes at the time of acetabular component implantation.

With regard to THA, the current orthopaedic literature demonstrates a clear relationship between acetabular component positioning, polyethylene wear and risk of dislocation. Problems with edge loading, stripe wear and squeaking are also associated with higher acetabular inclination angles, particularly in hard-on-hard bearing implants.

The important parameters of acetabular component positioning are depth, height, version and inclination.

Control of acetabular component inclination, particularly in the lateral decubitus position, is difficult and remains a challenge for the Orthopaedic Surgeon.

Accurate implantation of the acetabular component within the 'safe zone' of radiological inclination is dependent on:

* Operative version * Operative inclination * Pelvic position (Primarily, but not exclusively, abduction / adduction.)

This study aims to investigate the effect of patient pelvic positioning and method of acetabular component insertion on acetabular component inclination during Total Hip Arthroplasty (THA).

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Key information

Conditions

Total Hip Arthroplasty THA THR Total Hip Replacement

Age range

16 year–100 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Musgrave Park Hospital

Belfast, County Antrim, BT9 7JB, United Kingdom

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • All patients between the ages of 16 and 100 years awaiting primary Total Hip Arthroplasty the care of Professor D Beverland and Mr D Molloy in Musgrave Park Hospital will initially be invited to participate.

Exclusion criteria

  • Patients unable to provide fully informed consent.

Treatment and study plan

Operating table position 0° head down (Horizontal)

Procedure

Operating table position 7° head down.

Procedure

Operating table position Y° head down

Procedure

Operating table position Y° head down (angle required to obtain vertical Transverse Pelvis Lines).

Standard straight acetabular component introducer without alignment guide.

Device

Modified 35° acetabular component introducer.

Device

Inclinometer-assisted acetabular component introducer.

Device

Primary outcomes

  1. Radiological acetabular component inclination.

    Time frame: Radiological acetabular component inclination will be measured on the routine post-operative pelvic x-ray, usually within 48 hrs from time of surgery.

    The study has two primary aims, each with a different primary outcome.

    The first primary aim is to investigate the effect of adjusting patient pelvic position in the transverse plane by using a head down position of the operating table.

    This is to determine, when aiming for 35° of operative inclination, which operating table position most accurately achieves a target radiological inclination of 42° on the post-operative x-ray:

    • 0° head down (Horizontal),
    • 7° head down, or
    • Y° head down (Angle required to obtain vertical Transverse Pelvic Lines).

  2. Operative Acetabular Component Inclination.

    Time frame: Operative acetabular component inclination will be measured intra-operatively.

    The study has two primary aims, each with a different primary outcome.

    The second primary aim is to determine which of the three methods of acetabular component insertion most accurately allows the Orthopaedic Surgeon to obtain the desired operative inclination of 35° during THA when using a cementless cup:

    • Standard straight introducer without any alignment guide,
    • Modified 35° introducer with horizontal alignment guide, or
    • Digital inclinometer assisted introducer.

Secondary outcomes

  1. Proportion of cases in which the target radiological inclination of 42 +/- 5° is actually obtained.

    Time frame: Radiological acetabular component inclination will be measured on the routine post-operative pelvic x-ray, usually within 48 hrs from time of surgery.

Sponsors and collaborators

Lead sponsor

Musgrave Park Hospital

Other

Collaborators

  • Belfast Arthroplasty Research Trust (BART)
  • Belfast Health and Social Care Trust
  • Queen's University, Belfast

Registry information

Official study title

A Randomised Controlled Study Investigating the Effect of Patient Pelvic Positioning and Method of Acetabular Component Insertion on Acetabular Component Inclination During Total Hip Arthroplasty (THA).

Important dates

Study start
2013
Primary completion
2014
Study completion
2014
First posted
Apr 15, 2013
Registry last updated
Mar 22, 2016

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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