Improving Rehabilitation Outcomes After Total Hip Arthroplasty

Over the next 20 years, the number of total hip arthroplasties (THAs) performed to alleviate
pain and disability associated with osteoarthritis (OA) is expected to double to more than
500,000/year. Most patients report improved health-related quality of life following surgery;
however, deficits in physical function and quality of life persist. Specifically, Veterans
with THA have a higher prevalence of severe activities of daily living (ADL) limitations and
report severe physical health-related quality of life deficits. The increased THA
utilization, combined with long-term functional deficits which increase heath care
utilization, suggests a need for targeted rehabilitation strategies to improve physical
function for Veterans after THA.

Movement compensations are a biomarker of functional decline in a variety of older adult
populations. For patients with THA, persistent movement compensations are seen in activities
of daily living, such as level walking, sit-to-stand transitions, and stair climbing. These
movement compensations likely stem from a combination of poor muscle strength and a failure
to integrate available muscle strength into functional movement. Functional strength
integration (FSI) during daily tasks refers to the ability of the body to produce stable,
coordinated movements. At the hip joint, optimal FSI is largely dependent on the ability of
hip abductor muscles to produce sufficient hip abduction moments to stabilize the pelvis
during unilateral stance tasks. Thus, inability to integrate hip abductor muscle strength
during functional tasks results in poor pelvic stability and movement compensations. Lack of
FSI possibly explains the deficits in functional recovery after THA. However, current
rehabilitation practices do not target the integration of strength and functional movement to
resolve movement compensations.

Rehabilitation emphasizing functional strength integration after THA has the potential to
substantially improve postoperative physical function by remediating movement compensations
with greater hip abductor strength and recruitment during function, providing greater pelvic
control and better movement quality. Therefore, the investigators propose a randomized
controlled trial of 100 participants to determine if an 8-week functional strength
integration (FSI) program after THA improves physical function and muscle performance more
than control intervention (CON) after unilateral THA. The secondary goal is to determine if
FSI improves movement compensations during functional activity (walking and stair climbing).
Eight weeks of intervention will be initiated 2 weeks after THA to allow for early tissue
healing. Outcomes will be assessed pre-operatively (PRE); intervention mid-point (after 4
weeks intervention; POST1); intervention end-point (after 8 weeks intervention; POST2)
(primary endpoint); and late recovery (26 weeks after initiating rehabilitation; POST3).

Inclusion Criteria:

- BMI less than or equal to 40

- Receiving unilateral primary total hip arthroplasty for osteoarthritis

Exclusion Criteria:

- Severe contralateral leg OA (>= 5/10 pain with stair climbing)

- Other unstable orthopaedic conditions that limit function

- Neurological or pulmonary problems that severely limit function

- Uncontrolled hypertension or diabetes

- Use of illegal substances