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Trial registered on ANZCTR

Registration number
Ethics application status
Date submitted
Date registered
Date last updated
Type of registration
Prospectively registered

Titles & IDs
Public title
Post-market study on the impact of surgical approach on total hip replacement outcome
Scientific title
Impact of surgical approach on hip replacement outcome
Secondary ID [1] 289435 0
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Osteoarthritis 299125 0
Condition category
Condition code
Surgery 299142 299142 0 0
Surgical techniques
Musculoskeletal 299172 299172 0 0

Study type
Patient registry
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
Arm 1: Posterior lateral surgical approach (PLA)
PLA involves blunt dissection of the gluteus maximus, detachment of the external rotators and incision of the posterior part of the hip capsule. The hip is dislocated by internal rotation and flexion.
Arm 2: Anterior lateral surgical approach (ALA)
ALA involves detachment of the anterior one-third of the gluteus medius insertion and gluteus minimus insertion. Excision of the hip capsule is performed on the anterior side of the joint and the hip is dislocated by external rotation, adduction and flexion.
Arm 3: Direct anterior surgical approach (DAA)
DAA approaches the hip joint from the front of the joint, through a natural interval between the rectus femoris and gluteus medius muscles. There is no detachment of the gluteal muscles that attach to the posterior and lateral pelvis and femur.

Functional assessments and questionnaires on function and satisfaction will be completed at various timepoints up to 24 months post surgery.
Intervention code [1] 295028 0
Not applicable
Comparator / control treatment
No control group. Three surgical approaches will be compared as part of this study.
Control group

Primary outcome [1] 298622 0
The primary outcome measure for this study is the influence of three different surgical techniques on participant health-related quality of life (HRQoL) as assessed by the EuroQol-5D-5L (EQ-5D).
Timepoint [1] 298622 0
Pre-operatively, 2 weeks, 6 weeks, 3 months, 12 months and 24 months post-operatively
Primary outcome [2] 298657 0
Identification of hip-specific function using the Oxford Hip Score (OHS)
Timepoint [2] 298657 0
Pre-operatively, 2 weeks, 6 weeks, 3 months, 12 months and 24 months post-operatively
Secondary outcome [1] 324793 0
Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC), aimed at assessing pain, stiffness and physical function in patients with osteoarthritis
Timepoint [1] 324793 0
Baseline and 6 months postoperative
Secondary outcome [2] 324794 0
3-item short form (SF-3a) to assess pain intensity for patients
Timepoint [2] 324794 0
Baseline, 6 weeks, 3 months, 12 months and 24 months post-operatively
Secondary outcome [3] 324795 0
4-item short form (SF-4a) to assess physical function and measure current self-reported capabilities
Timepoint [3] 324795 0
Baseline, 6 weeks, 3 months, 12 months and 24 months post-operatively
Secondary outcome [4] 324797 0
Patient satisfaction scale, assessed using a 5-point Likert scale, ranging from 'true' to false' and 'very satisfied' to 'very dissatisfied'
Timepoint [4] 324797 0
Baseline, 6 weeks, 3 months, 12 months and 24 months post-operatively
Secondary outcome [5] 324861 0
The performance and position of the prosthesis will be determined and monitored by assessing plain radiographs pre- and post-surgery at follow-up intervals. Measurements collected include:

Acetabular inclination
Acetabular version
Stem varus/valgus
Lateral stem alignment
Radiolucencies (Size and location - Gruen Zones)
Timepoint [5] 324861 0
Baseline, at discharge, 3 months, 12 months and 24 months post-operatively
Secondary outcome [6] 324862 0
The CT protocol aims to provide specific information to investigators on the placement of participants’ prostheses, illustrating leg length, location of the hip joint centre, femoral off-set and acetabular cup position. The Optima CT580 W multifunction wide bore CT scanner will be utilised for this purpose, which provides routine 16-slice acquisition without coverage compromise.
Timepoint [6] 324862 0
Baseline and 3 months post-operative
Secondary outcome [7] 324863 0
Gait analysis will be assessed by an eight camera Qualisys Motion Capture System together with Visual3D software for biomechanical analyses. The software Qualisys Track Manager (QTM) controls the cameras, calibration, capture, identification and export of data. Data from force plates (force and motion capture) and dynamic electromyography (EMG) is also integrated in the system. EMG will be used to investigate the patterns of muscle activity during gait.
Timepoint [7] 324863 0
Baseline, 6 weeks, 3 months, 6 months, and 12 months post-operative
Secondary outcome [8] 324864 0
Sit to stand protocol (STS). In addition to gait analysis, assessment of a patient’s ability to rise from a seated position is important to assess abnormal gait patterns that may persist post-operatively despite pain resolution and patient satisfaction.
Timepoint [8] 324864 0
Baseline, 6 weeks, 3 months, 6 months and 12 months post-operative
Secondary outcome [9] 324865 0
Accelerometer. Patients will be required to wear a GeneActiv physical activity monitor for one week continuously following their pre-operative, 6 weeks and 6 month visit. This will be used to monitor the patients’ activity during their daily living following surgery and provide some objective data on the frequency of loading during recovery.
Timepoint [9] 324865 0
Baseline, 6 weeks and 6 months post-operatively

Key inclusion criteria
Any osteo-arthritic patient that presents to an Investigator for a routine hip replacement surgery and is able to provide informed consent.
Any patient able to complete the required patient reported outcome measures.
Any patient able to undergo the required radiological examinations.
Minimum age
18 Years
Maximum age
No limit
Both males and females
Can healthy volunteers participate?
Key exclusion criteria
Participants with difficulty in comprehending study protocol through written or verbal English
Participants who, in the opinion of the Investigator, have an existing condition that would compromise their participation and follow-up.
Concurrent pregnancy.
Participants who are known drug or alcohol abusers or with psychological disorders that could affect follow-up care or treatment outcomes.
Participants who are currently involved in any injury litigation claims.
Participants with chronic gait affecting neurological conditions (e.g. stroke, Parkinson’s, Multiple sclerosis).
Participants with congenital hip defects.

Study design
Defined population
Statistical methods / analysis
Previous studies suggest the value of EQ-5D in the arthroplasty setting pre- and post-operatively, indicating a sound basis for selection herein. The literature suggests a Cohen’s d of 0.3 (when converted to f = 0.15) for EQ-5D, demonstrating a small effect size when used in an orthopaedic setting. Convention suggests f effect size range of 0.1 small, 0.25 medium and 0.40 large. Therefore, we selected 0.15 for our sample size calculation. Thus for an effect size of f 0.15, a value of 0.05 and 1-beta power of 0.90, the total sample size calculated was 567. Assuming 10% drop-out or loss to follow-up, a total sample size n = 624 = 208 participants/group.
Given this is a longitudinal study, in order to investigate relationships over time for continuous outcomes from the PROMs and radiographic measures, a mixed model with repeated measures will be performed. Sub-group analyses of age, gender, and other surgery demographics will also be performed.

Recruitment status
Not yet recruiting
Date of first participant enrolment
Date of last participant enrolment
Date of last data collection
Sample size
Accrual to date
Recruitment in Australia
Recruitment state(s)
Recruitment hospital [1] 5975 0
Southern Adelaide Health Institute - Belair
Recruitment postcode(s) [1] 13396 0
5052 - Belair

Funding & Sponsors
Funding source category [1] 293810 0
Self funded/Unfunded
Name [1] 293810 0
No funding source
Address [1] 293810 0
No funding source
Country [1] 293810 0
Primary sponsor type
Other Collaborative groups
The International Musculoskeletal Research Institute Incorporated
13 Laffers Road, Belair SA 5042
Secondary sponsor category [1] 292641 0
Name [1] 292641 0
Address [1] 292641 0
Country [1] 292641 0

Ethics approval
Ethics application status
Ethics committee name [1] 295243 0
Bellberry Limited
Ethics committee address [1] 295243 0
129 Glen Osmond Road Eastwood South Australia 5063
Ethics committee country [1] 295243 0
Date submitted for ethics approval [1] 295243 0
Approval date [1] 295243 0
Ethics approval number [1] 295243 0

Brief summary
Hip replacement is a commonly performed procedure for the treatment of arthritic conditions of the hip joint and since 2003 the number of hip replacement procedures has significantly increased by 46.5% in Australia. The procedure is intended to relieve pain, restore function to the hip joint and ensure maximal longevity of the implant.

Different surgical approaches to hip replacement have been developed over many years with various levels of clinical support. However, anteriorly-based surgical approaches, which open the joint capsule from the front of the joint, have been increasingly used in recent times.

The main aim of this study is to assess whether the surgical approach to hip replacement surgery impacts patient outcome. Three different surgical approaches will be assessed across a large patient sample, regardless of prosthesis type or surgeon. This will be assessed primarily by patient satisfaction with the surgery, following the collection of longitudinal functional (patient-reported outcomes), radiological data and gait analyses.

The secondary aim of the study will be to define preoperative patient characteristics as predictors of outcome following different surgical approaches to THA. To illustrate any potential identifying criteria for future surgical approach selection.
Trial website
Trial related presentations / publications
Public notes

Principal investigator
Name 66666 0
Prof Jeganath Krishnan
Address 66666 0
The International Musculoskeletal Research Institute Incorporated
13 Laffers Road, BELAIR SA 5052
Country 66666 0
Phone 66666 0
+618 8267 8233
Fax 66666 0
+618 8278 2172
Email 66666 0
Contact person for public queries
Name 66667 0
Mr Michael Nganga
Address 66667 0
The International Musculoskeletal Research Institute Incorporated
13 Laffers Road, BELAIR SA 5052
Country 66667 0
Phone 66667 0
+618 7231 8452
Fax 66667 0
Email 66667 0
Contact person for scientific queries
Name 66668 0
Ms Annika Theodolou
Address 66668 0
The International Musculoskeletal Research Institute Incorporated
13 Laffers Road, Belair SA 5052
Country 66668 0
Phone 66668 0
+618 7231 8452
Fax 66668 0
Email 66668 0

No information has been provided regarding IPD availability
Summary results
No Results