Trial Review

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Trial registered on ANZCTR


Registration number
Help: Registration number
ACTRN12626001337369
Ethics application status
Help: Ethics application status
Approved
Date submitted
Help: Date submitted
19/10/2026
Date registered
Help: Date registered
5/11/2026
Date last updated
Help: Date last updated
5/11/2026
Date data sharing statement initially provided
Help: Data sharing statement date
5/11/2026
Type of registration
Help: Type of registration
Prospectively registered

Titles & IDs
Public title
Patient perception of leg-length difference after total hip replacement and its relationship with radiographic leg-length measurements
Scientific title
Association between postoperative radiographic limb-length imbalance and patient-perceived leg-length discrepancy following primary total hip arthroplasty: a prospective longitudinal observational cohort study
Additional trial identifiers [1] 318700 0
Nil
Universal Trial Number (UTN)
Trial acronym
CLEAR II
Related trial records

Health condition
Health condition(s) studied:
Hip osteoarthritis 343917 0
Total Hip Arthroplasty 343992 0
Condition category
Condition code
Musculoskeletal 340057 340057 0 0
Osteoarthritis
Surgery 340127 340127 0 0
Other surgery

Intervention/exposure
Study type
Observational
Patient registry
False
Target follow-up duration
Target follow-up type
Description of the intervention or exposure
The exposure of interest is postoperative radiographic limb-length imbalance following primary total hip arthroplasty, including anatomical and functional limb-length discrepancy, pelvic obliquity, and hip reconstruction measurements. Participants will be observed prospectively from before surgery to 12 months after surgery. Imaging measurements will be obtained preoperatively and postoperatively, and patient-perceived leg-length discrepancy will be assessed at 4–6 weeks and 12 months after surgery. The primary analysis will evaluate the association between postoperative radiographic limb-length imbalance and patient-perceived leg-length discrepancy at 12 months. Total hip arthroplasty is performed as part of usual clinical care and is not assigned by the study.

Participants will undergo their usual preoperative clinical assessment and imaging, including standing EOS imaging, an anteroposterior pelvic radiograph and CT-based surgical planning. Following surgery, participants will undergo one additional research-specific limited-field low-dose CT scan to assess hip reconstruction. This scan covers the region from just above the acetabulum to the lesser trochanter and does not involve injection of contrast, tracer or dye. At 4–6 weeks postoperatively, participants will undergo standing EOS imaging as part of routine follow-up. At 12 months, participants will undergo a weight-bearing anteroposterior pelvic radiograph as part of routine follow-up.

Participants will complete patient-reported assessments preoperatively, at 4–6 weeks and at 12 months postoperatively. These include the Oxford Hip Score and study-specific questions regarding perceived leg-length difference, including its direction and magnitude, degree of bother, use of a shoe raise and satisfaction following surgery. Baseline demographic and clinical information, including height and weight, will also be collected from the clinical record or preoperative assessment; where height and weight are unavailable, these will be measured directly by the research team at baseline.

Study assessments will be undertaken in conjunction with the participant's routine clinical pathway wherever possible. Clinical follow-up will be conducted by the treating orthopaedic team at St John of God Murdoch Hospital. Imaging will be performed by appropriately trained radiography staff, with the additional research-specific postoperative low-dose CT performed by SKG Radiology. Imaging measurements will subsequently be assessed by study investigators.
Intervention code [1] 335586 0
Diagnosis / Prognosis
Description of the comparator or control
No control group
Control group
Uncontrolled

Outcomes
Primary outcome [1] 347205 0
Patient-perceived leg-length discrepancy at 12 months following total hip arthroplasty.
Timepoint [1] 347205 0
12 months postoperatively.
Secondary outcome [1] 469472 0
Direction of patient-perceived leg-length discrepancy
Timepoint [1] 469472 0
4–6 weeks and 12 months postoperatively.
Secondary outcome [2] 469473 0
Patient-reported hip function
Timepoint [2] 469473 0
Preoperatively, 4–6 weeks postoperatively, and 12 months postoperatively.
Secondary outcome [3] 469474 0
Patient satisfaction following total hip arthroplasty
Timepoint [3] 469474 0
4–6 weeks and 12 months postoperatively.
Secondary outcome [4] 469475 0
Postoperative radiographic limb-length discrepancy
Timepoint [4] 469475 0
4–6 weeks postoperatively.
Secondary outcome [5] 469476 0
Postoperative pelvic obliquity
Timepoint [5] 469476 0
4–6 weeks postoperatively.
Secondary outcome [6] 469477 0
Postoperative hip length
Timepoint [6] 469477 0
During the inpatient postoperative period following total hip arthroplasty.
Secondary outcome [7] 469840 0
Magnitude of patient-perceived leg-length discrepancy
Timepoint [7] 469840 0
4–6 weeks and 12 months postoperatively.
Secondary outcome [8] 469841 0
Degree of bother associated with patient-perceived leg-length discrepancy
Timepoint [8] 469841 0
4–6 weeks and 12 months postoperatively
Secondary outcome [9] 469842 0
Use of a shoe raise for patient-perceived leg-length discrepancy
Timepoint [9] 469842 0
4–6 weeks and 12 months postoperatively
Secondary outcome [10] 469846 0
Postoperative femoral offset
Timepoint [10] 469846 0
During the inpatient postoperative period following total hip arthroplasty.
Secondary outcome [11] 469847 0
Postoperative acetabular offset
Timepoint [11] 469847 0
During the inpatient postoperative period following total hip arthroplasty.
Secondary outcome [12] 469848 0
Postoperative combined offset
Timepoint [12] 469848 0
During the inpatient postoperative period following total hip arthroplasty.

Eligibility
Key inclusion criteria
Adults aged 18 years or older undergoing primary total hip arthroplasty for primary or secondary osteoarthritis at St John of God Murdoch Hospital. Participants must be able to provide informed consent, complete the study questionnaires, and undergo the required study imaging and follow-up.
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Healthy volunteers
No
Key exclusion criteria
Revision total hip arthroplasty; inability to provide informed consent or complete study questionnaires; inability to undertake the required study imaging or participate in scheduled follow-up; or other circumstances that, in the opinion of the investigators, would prevent reliable participation in the study.

Study design
Purpose
Natural history
Duration
Longitudinal
Selection
Defined population
Timing
Prospective
Statistical methods / analysis
The target recruitment is 280 participants, allowing for approximately 10% attrition and providing an expected evaluable sample of approximately 250 participants. The primary outcome is patient-perceived leg-length discrepancy at 12 months. Assuming a prevalence of patient-perceived leg-length discrepancy of approximately 10–20%, an evaluable sample of 250 participants provides approximately 80% power at a two-sided alpha of 0.05 to detect an odds ratio of approximately 1.6–1.9 per one standard deviation increase in radiographic limb-length discrepancy. This represents a moderate and clinically meaningful association.

Recruitment
Recruitment status
Not yet recruiting
Date of first participant enrolment
Anticipated
1/12/2026
Actual
Date of last participant enrolment
Anticipated
30/04/2028
Actual
Date of last data collection
Anticipated
30/04/2029
Actual
Sample size
Target
280
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
WA
Recruitment hospital [1] 30381 0
St John of God Hospital, Murdoch - Murdoch
Recruitment postcode(s) [1] 46796 0
6150 - Murdoch

Funding & Sponsors
Funding source category [1] 323266 0
Charities/Societies/Foundations
Name [1] 323266 0
Orthopaedic Research Foundation of Western Australia (ORFWA)
Country [1] 323266 0
Australia
Primary sponsor type
Individual
Name
Professor Piers Yates - St John of God Murdoch Hospital
Address
Country
Australia
Secondary sponsor category [1] 326240 0
None
Name [1] 326240 0
Address [1] 326240 0
Country [1] 326240 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 321663 0
St John of God Health Care Human Research Ethics Committee
Ethics committee address [1] 321663 0
Ethics committee country [1] 321663 0
Australia
Date submitted for ethics approval [1] 321663 0
19/08/2026
Approval date [1] 321663 0
15/10/2026
Ethics approval number [1] 321663 0
2423

Summary
Brief summary
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 154446 0
Prof Piers Yates
Address 154446 0
St John of God Murdoch Hospital, 1 Barry Marshall Parade, Murdoch WA 6150, Australia
Country 154446 0
Australia
Phone 154446 0
+61 8 9475 2929
Fax 154446 0
Email 154446 0
[email protected]
Contact person for public queries
Name 154447 0
Fabio Mancino
Address 154447 0
University of Western Australia, 35 Stirling Highway, Crawley, Western Australia 6009, Australia
Country 154447 0
Australia
Phone 154447 0
+61 8 6488 6000
Fax 154447 0
Email 154447 0
[email protected]
Contact person for scientific queries
Name 154448 0
Piers Yates
Address 154448 0
St John of God Murdoch Hospital, 1 Barry Marshall Parade, Murdoch WA 6150, Australia
Country 154448 0
Australia
Phone 154448 0
+61 8 9312 1135
Fax 154448 0
Email 154448 0
[email protected]

Data sharing statement
Will the study consider sharing individual participant data?
No


What supporting documents are/will be available?

No Supporting Document Provided


Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.