Progressive Resistance Training Versus Total Hip Arthroplasty in Patients With Hip Osteoarthritis

Progressive Resistance Training Versus Total Hip Arthroplasty in Patients With End-stage Hip Osteoarthritis (PROHIP): A Multicentre, Parallel-group, Randomised Controlled Superiority Trial

Hip osteoarthritis is associated with joint pain, physical disability, decreased muscle strength and poor health status, and the most common cause for total hip arthroplasty. No studies have investigated the effect of total hip arthroplasty compared to non-surgical treatment in patients with end-stage hip osteoarthritis. This comparison is of upmost importance as it is unknown whether non-surgical treatment may be used as an alternate to surgery.

The purpose of this study is to investigate whether total hip arthroplasty followed by standard care is superior to progressive resistance training for improving hip function and pain in patients with end-stage hip osteoarthritis.

The hypothesis is that patients treated with total hip arthroplasty will improve more than patients treated with progressive resistance training.

Hip osteoarthritis (OA) is associated with joint pain, dysfunction of activities of daily living (ADL), decreased muscle strength and decline in health-related quality of life status, and the most common cause for total hip arthroplasty (THA). In Denmark, approximately 10.400 primary THA surgeries are performed annually, and the yearly incidence rate of this procedure has increased dramatically from 80 to 180 per 100.000 persons between 1995 and 2016. However, some patients experience long-term pain and may never recover full physical function and muscle strength after surgery.

Exercise has been shown to improve physical function and reduce pain in people with hip OA, and is recommended initially as a treatment in international clinical guidelines. Furthermore, a recent randomised controlled trial (RCT) showed clinically relevant improvements in ADL and muscle function after 10-weeks of supervised explosive-type progressive resistance training (PRT) in patients with end-stage hip OA scheduled for THA compared to standard preoperative care.

To date, no RCTs have investigated the effect of THA followed by standard postoperative care compared to supervised explosive-type PRT in patients with end-stage hip OA. Therefore, this highlights the need for a high-quality trial as it is unknown whether non-surgical treatment may be used as an alternate to surgery.

The aim of this randomised controlled trial is to investigate whether THA followed by standard care is superior to a 12-week supervised explosive-type PRT programme for improving patient-reported hip function and pain 6 months after initiating the intervention, measured using the Oxford Hip Score (OHS), in patients with end-stage hip OA eligible for THA. Exploratory outcome time-points will be assessed at 3, 12, 24 and 60 months after initiating the intervention.

The hypothesis is that THA followed by standard care is superior to a 12-week supervised explosive-type PRT programme for improving patient-reported hip function and pain 6 months after initiating the intervention, measured using the OHS, in patients with end-stage hip OA eligible for THA.

Observational cohort:

Patients fulfilling the eligibility criteria but declining to participate in the RCT will be asked to participate in a prospective observational cohort study using the same primary end-point (6 months), exploratory time-points (3, 12, 24 and 60 months), and patient-reported outcomes, but following usual clinical practice.

Inclusion Criteria:

1. Adults aged ≥50 years
2. Clinical history and symptoms consistent with primary hip osteoarthritis (including hip osteoarthritis due to mild hip dysplasia that may be treated with standard components) and radiographic verified hip osteoarthritis defined as joint space narrowing <2 mm
3. Considered eligible for total hip arthroplasty by an orthopaedic surgeon (i.e. duration of symptoms >3 months, hip related pain, functional impairment or decreased range of motion (ROM), and attempted treatment with analgesics)

Exclusion Criteria:

1. Severe walking deficits (dependency of two crutches or walker)
2. Body Mass Index >35 kg/m2
3. Lower extremity fractures within one-year prior to inclusion
4. Planned other lower extremity surgery within six months
5. Cancer diagnosis and receiving chemo-, immuno- or radiotherapy
6. Neurological diseases (e.g. previous stroke, multiple sclerosis, Parkinson's, Alzheimer's).
7. Other reasons for exclusion (i.e. inadequacy in written and spoken Danish, mentally unable to participate, physically unable to comply with the PRT protocol due to comorbidity (e.g. severe heart disease, previous major lower extremity surgery within six-months) etc.).