Comparing Dual-mobility Cups Versus Unipolar Cups for Unselected Primary Total Hip Arthroplasty by Direct Anterior Approach
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18+
SponsorElsan
About this trial
THA comprises the replacement of the damaged bone and cartilage with prosthetic components. The proximal end of the femur is replaced with a stem and ball/head, while the acetabulum is most commonly replaced with a unipolar cup (UP) that consists of a liner inside of a metal shell. UP cups are associated with risks of dislocations, especially in elderly and female patients, as well as in patients with lumbar stiffness or operated for femoral neck fractures. In fact, one of the most common reasons for early revision of UP cups are dislocations.
Dual-mobility (DM) cups were introduced in the 1970s by the French surgeon Gilles Bousquet, as an alternative to UP cups. They are made up of two articulations, a femoral head moving inside a mobile polyethylene liner, which in turn moves inside a metal shell. This design allows for a greater jump distance and range of motion (ROM) compared to UP cups, thus resulting in reduced rates of dislocation.
A recent systematic review that evaluated 5 case-control studies (549 DM cups vs 649 UP cups) and 3 registry studies (5935 DM cups vs 217362 UP) found that in case-control studies, the dislocation rates were 0.2% for DM cups versus 7.1% for UP cups (p=0.009). Furthermore, in registry studies the revision rates due to dislocation were 0.2% for DM cups versus 0.5% for UP cups (p=0.050).
Nonetheless, there have been some concerns associated with the use of DM cups, including intra-prosthetic dislocations (IPD), polyethylene wear, and iliopsoas impingement. Since the early 2000s, new improvements in the design of DM cups have nearly eliminated the risk of IPD, and the use of ultra-high molecular weight polyethylene (UHMWPE) has greatly reduced wear rates, even in young and active patients. Lastly, although some studies have reported iliopsoas impingement with DM cups, the impingement is usually against the optional fixations, and not against the mobile polyethylene insert.
The hypothesis of the present interventional randomised controlled trial (RCT) is that THA using DM cups will not provide inferior outcomes compared to THA using UP cups, in terms of hip awareness measured using the forgotten joint score (FJS).
Eligibility criteria
This trial does not accept healthy volunteersQualifiers
men and women aged ≥18 years old
set to undergo elective primary THA via direct anterior approach (DAA)
affiliated with a social security scheme
able to answer questionnaires and to communicate freely in French
Disqualifiers
with prior ipsilateral hip surgery
with prior contralateral hip surgery
that require acetabular cup diameters ≤50mm (because DM cups are not available from the same manufacturer for diameters ≤50mm, and UP cups require head diameters of 36mm and thus minimum cup diameters of 52mm)
undergoing emergency or trauma surgery (e.g. femoral neck fractures)
Trial design
Design model
Parallel
Treatments tested in this trial
Primary total hip arthroplasty using dual-mobility cup
Procedure/SurgeryReplacement of hip articulating surface.
Primary total hip arthroplasty using unipolar cup
Procedure/SurgeryReplacement of hip articulating surface.
Treatment groups
300 Participants
are divided into 2 treatment groupsGroup A: THA with dual-mobility cupActive comparator 1 intervention
Group B: THA with unipolar cupActive comparator 1 intervention
Trial outcomes
Primary outcomes
1
Forgotten Joint Score between DM cup group and UP cup group
The primary outcome is defined as patient-reported hip awareness at 2 years postoperatively, measured using the Forgotten Joint Score (FJS). The FJS is a validated self-administered questionnaire that measures the patients' ability to forget about a joint as a result of successful treatment. The questionnaire comprises 12 items. Each item is scored using a 5-point Likert scale, ranging from "never" (0 points) to "mostly" (4 points). The final FJS score is calculated as the addition of all items, divided by the number of items answered. The mean score is then multiplied by 25, and that value is subtracted from 100. The FJS ranges from 0 to 100, with 100 corresponding to the best score: the patient has forgotten about their joint.
Time frame
2 yearsSecondary outcomes
1
Forgotten Joint Score between DM cup group and UP cup group
Patient-reported hip awareness at 3 months and 1 year postoperatively, measured using the FJS. The FJS is a validated self-administered questionnaire that measures the patients' ability to forget about a joint as a result of successful treatment. The questionnaire comprises 12 items. Each item is scored using a 5-point Likert scale, ranging from "never" (0 points) to "mostly" (4 points). The final FJS score is calculated as the addition of all items, divided by the number of items answered. The mean score is then multiplied by 25, and that value is subtracted from 100. The FJS ranges from 0 to 100, with 100 corresponding to the best score: the patient has forgotten about their joint.
Time frame
3 months and 1 year2
To compare the patient's hip/groin pain between DM cups versus UP cups, as well as to compare the net change from baseline
Patient-reported hip/groin pain preoperatively and at 3 months, 1 year and 2 years postoperatively, measured using a numeric rating scale (NRS). The net change will be calculated at 3 months, 1 year and 2 years taking the preoperative value as baseline. The NRS ranges from 0 to 10, with 0 representing no pain, and 10 representing the maximum pain imaginable.
Time frame
preoperatively, at 3 months, 1 year and 2 years3
To compare the patient's hip function between DM cups versus UP cups
Patient-reported hip function preoperatively and at 3 months, 1 year and 2 years postoperatively, measured using the Oxford hip score (OHS). The OHS is a validated self-administered questionnaire that assesses disability, in terms of function and pain, in patients undergoing THA. The questionnaire comprises 12 items. Each item is scored using a 5-point Likert scale, from 0 to 4 points, with 0 representing the worst outcome and 4 the best. The final OHS score is calculated as the addition of all items. The OHS ranges from 0 to 48, with 48 corresponding to the best score. Clinician-reported hip ROM preoperatively and at 3 months and 1 year postoperatively. ROM will be measured in degrees, in flexion, extension, internal rotation, external rotation, abduction, adduction.
Time frame
preoperatively, at 3 months, 1 year and 2 years4
To compare the patient's sports activity between DM cups versus UP cups
Patient-reported return to sports (yes/no) and time to return to sports (months) will be assessed at 1 year postoperatively.
Time frame
1 yearOther outcomes
1
To evaluate whether age is associated with the Forgotten Joint Score
Association between age and the FJS at 2 years.
Time frame
2 years2
To evaluate whether sex is associated with the Forgotten Joint Score
Association between sex and the FJS at 2 years.
Time frame
2 years3
To evaluate whether body mass index is associated with the Forgotten Joint Score
Association between body mass index and the FJS at 2 years.
Time frame
2 years4
To evaluate whether preoperative hip pain is associated with the Forgotten Joint Score
Association between preoperative hip pain and the FJS at 2 years.
Time frame
2 years Source ClinicalTrials.gov