Direct Superior Approach Versus PosteroLateral Approach in Total Hip Arthroplasty (SPLAsH)

Objective: The primary objective is to evaluate health related quality of life (HRQoL) after THA using the DSA compared to the golden standard PLA in patients with incapacitating hip osteoarthritis after two weeks. The secondary objectives are divided into 1) long-term HRQoL evaluation, 2) physical performance, 3) radiologic muscle atrophy and component placement of the THA, 4) validation of a new metal artifact reduction technique for CT, and 5) relationship urinary incontinence and muscle atrophy.

Study design: Multicenter, prospective, double blinded, randomized controlled intervention study in which the used operation method is not shared with the patient until one year after surgery and in which the study researcher is also blinded.

Study population: A total of 211 men and women, age ≥ 18 years, with symptomatic hip osteoarthritis in whom THA is indicated.

Intervention (if applicable): For this randomized controlled trial (RCT), patients will be randomly allocated in one of two groups: one group receives THA by using PLA, the other group receives THA by using DSA.

Main study parameters/endpoints: As primary outcome specifically the Hip Disability and Osteoarthritis Outcome Score- Physical Function Short Form (HOOS-PS) is used for the short-term HRQoL.

Secondary parameters/endpoints are split up into different categories. 1) HRQoL evaluation on the long term using patient reported outcome measures (PROMs) (NRS score, Short form-12 (SF-12), HOOS subscales, Global rating of change, and Euro Quality of Life questionnaire). 2) Physical function using physical functioning test (Timed Up and Go test, 40-meter self-paced walk test for hip osteoarthritis and Stair Climb Test). 3) Muscle atrophy measurements using CT scans. Muscle atrophy is expressed in both quantity of muscle volume loss and extend of fatty infiltration using the Goutallier scale. Component placement is measured in different angles. 4) Evaluation of a new metal artifact reduction technique for CT images. 5) Relationship between muscle atrophy and urinary incontinence after total hip replacement.

Other study parameters include preoperative demographics such as age and gender, perioperative data such as blood loss, use of analgetics, operation time and postoperative complications such as infection, aseptic loosening and dislocation.

• Numeric Rating Scale (NRS) [Time frame: pre-operatively and 2 weeks, 6 weeks, 3 months and 12 months postoperatively]
• Short Form-12 (SF-12) [Time frame: pre-operatively and 2 weeks, 6 weeks and 12 months postoperatively]
• Hip disability and Osteoarthritis Outcome Score (HOOS) [Time frame: pre-operatively and 2 weeks, 6 weeks and 12 months postoperatively]
• Euro Quality of Life (EQ-5D) [Time frame: pre-operatively and 2 weeks, 6 weeks, 3 months and 12 months postoperatively]
• Global Rating of Change scale [Time frame: pre-operatively and 2 weeks, 6 weeks, 3 months and 12 months postoperatively]
• Timed Up and Go test (TUG test) [Time frame: pre-operatively and 2 weeks, 6 weeks and 12 months postoperatively]
• 40 meter self-paced walk test for hip osteoarthritis [Time frame: pre-operatively and 2 weeks, 6 weeks and 12 months postoperatively]
• Stair climb test [Time frame: pre-operatively and 2 weeks, 6 weeks and 12 months postoperatively]
• Muscle atrophy by using Computer Tomography (CT) scanner [Time frame: pre-operatively and 12 months postoperatively]
• Computer Tomography (CT) image with orthopedic metal artefact reduction (O-MAR) [Time frame: pre-operatively and 12 months postoperatively]
• Postoperative cup position on Computer Tomography (CT) image [Time frame: 12 months postoperatively]
• Comparing definite cup position with preoperative planned cup position [Time frame: pre- operatively and 12 months postoperatively]