Purpose:

The purpose of this study is to determine the effect of pre operative resistance training on subjects scheduled for total hip arthroplasty due to primary osteoarthritis.

Background:

Decreasing performance with age due to age related muscle loss is well known. Resistance training in elderly has shown significant effect in regaining both muscle force and function.

It has been shown that a chronic condition with limitations in function as seen in osteoarthritis of the hip decreases both muscle performance and size.

Studies of resistance training of the hip related muscle groups in the early postoperative period after total hip arthroplasty have shown significant effect on muscle force and function.

Few studies have investigated preoperative intervention, all with lighter types of training such as water pool training.

The effect of preoperative resistance training on subjects with primal osteoarthritis of the hip is yet to be described.

Study hypothesis:

Preoperative resistance training will significant improve outcomes on both primal and secondary effect parameters pre surgery and at 1 year followup.

BACKGROUND:

Osteoarthritis of the hip is a common condition among elderly. In Denmark 8000 people underwent operation with total hip arthroplasty in 2007, due to osteoarthritis (Danish Register of hip arthroplasty 2007)).

The number of hip arthroplasties has been doubled the last decade mostly due to an increase in the age group 70-79 years (Danish Register of Hip Arthroplasty 2007). The population of elderly has been increased by to the demographic changes (Danish Statistics). A larger need for treatment could be expected in the future due to this development.

The indications of surgery is pain, reduced function and impaired quality of life related to the hip.

Osteoarthritis is divided into two groups: Primary osteoarthritis and secondary osteoarthritis. The cause of primary osteoarthritis is largely unknown. There is a certain amount of genetic predisposition (Felson et al. 1998), the condition is more common among women and the risk of osteoarthritis is larger with higher body weight (Felson et al. 1988) (Anderson et al. 1988).

Secondary osteoarthritis is seen in rheumatoid arthritis, other types of arthritis and due to morphological conditions in the hip like dysplasia (Jacobsen et al 2005).

Aging is followed by loss of muscle mass -a process accentuated in the late senium (Kyle et al 2001). Loss of muscle mass is related to loss of functions in daily living (Kyle et al 2001)(Jannsen et al 2002).

Conditions with impact on daily living, such as osteoarthritis, is likely to accentuate this process even further. It has been shown that unilateral osteoarthritis of the hip is correlated with a reduction in muscle force, muscle size (cross sectional area) and level of neuromuscular activation (Suetta et al 2007), (Suetta et al 2004).

LOSS OF MUSCLE MASS -AN IMPORTANT FACTOR IN PHYSICAL FUNCTION AND TRAINING IN ELDERLY:

The loss of muscle mass is considered one of the most important factors in loss of function and mobility during aging (Volpi et al 2007).

The loss of lean muscle mass (LLM) is substantial during adult life. In young adults LLM contributes with 50 % to the total body mass (Short et al 2000). Studies have shown a 12-14 % loss of LMM and muscle strength pr decade after the age of 40 (Nair et al 1995), (Roth et al 2000), (Porter et al 1995), (Young et al 1985). At the same time muscle fiber types and fiber composition undergo changes along with changes in the hormonal status - both with effect on tissue regeneration (Lexell et al 1995), (Verdijk et al 2007), (Abbasi et al 1993), (Sattler et al 2009).

RESISTANCE TRAINING IN ELDERLY:

Among healthy elderly resistance training (RT) has significant effect on muscle strength (concentric force - 1 repetition max (1RM), maximum isometric force), physical function and body composition (DEXA scan, ultra sound).

In RT studies the training intensity was typically 80% of 1RM (Sillanpää et al 2008), (Sillanpää et al 2009), (Fiatarone et al 1990), (Fiatarone et al 1994), (Hikida et al 2000) 2-3 times a week, in a period of 8-12 weeks (Vandervoort et al 2003).

RESISTANCE TRAINING AND OSTEOARTHRITIS:

There has only been conducted a few studies concerning progressive resistance training in the period around surgery.

Two clinically controlled trials describe progressive resistance training in the post surgery period and only one study describes the effect of genuine progressive resistance training:

Hesse et al (2003) use treadmill training with partly body weight support after hip arthroplasty. They found significant effects on Harris Hip score and manually rated muscle force. Gait speed remained unchanged.

Suetta et al (2004) (2008) use unilateral progressive resistance training of quadriceps muscle groups in a 12 week program post hip arthroplasty. As shown in healthy elderly they find significant effects on outcome measures like physical performance tests (as stair climb, muscular size (computer tomography scan) and max isokinetic knee extension moment.

RESISTANCE TRAINING PRE-SURGERY VERSUS POST-SURGERY

Only few studies describe different training interventions in the preoperative stage in patients with osteoarthritis (D'Lima et al 1996), (Wang et al 2003), (Gilbey et al 2003), (Rodgers et al 1998), (Gill et al 2009). Most of them describe intervention before total knee arthroplasty.

Only 3 studies designed as randomized clinically controlled studies are conducted pre-surgery on patients scheduled for hip arthroplasty (Wang et al 2003), (Gilbey et al 2003), (Gill et al 2009).

All of those with low intensity training like water pool therapy. To our knowledge no studies have described the effect of progressive resistance training as intervention in the pre operative period.

The findings by Suetta et al (2008) of the effect of progressive resistance training post surgery motivates this study of similar intervention in a pre surgery setting.

PURPOSE:

The purpose of this study is:

• To determine the effect of preoperative resistance training on subjects scheduled for total hip arthroplasty due to primary osteoarthritis.
• To determine the effect pre-surgery and post surgery with 1 year follow up.

HYPOTHESIS:

Preoperative resistance training will significant improve outcomes on both primal and secondary effect parameters pre-surgery and at 1 year follow up.

Inclusion Criteria:

• All patients scheduled for total hip arthroplasty due to primary osteoarthritis with an age of 50 years or older.
• Patients in the intervention group must participate in 80% of the training as a minimum and more than 2 skipped sessions in a row is not allowed.

Exclusion Criteria:

• Rheumatoid arthritis (RA) or other types of arthritis other than primary osteoarthritis.
• Uremia
• Cancer
• Systemic treatment with glucocorticoid more than 3 months the last 5 years with a daily dose > 5 mg.
• Fracture of the hip (ipsi or contralateral)
• Other fracture of the lower extremities the last year
• Other condition with reduced function (ex polio seq.)
• Weight above 135 kg