The effect of physiotherapy training programme on postural stability in men with hip osteoarthritis

Abstract

This study presents the influence of a physiotherapy training programme over the standing balance in elderly hip osteoarthritis (OA) patients. The aim of this study was to analyse the standing balance in elderly male hip OA patients, and to investigate how the physiotherapy training programme could significantly improve the balance. The tests were performed on a group of selected OA patients as well as on a group of age- and sex-matched healthy control subjects before and after the physiotherapy training programme. The significant differences were observed between the results of tests performed before and after the physiotherapy training programme, and also between the hip OA patients and the control subjects in all CPF parameters, in both sagittal and frontal planes. In conclusion, the hip OA has an effect on the process of maintaining the standing balance. Moreover the physiotherapy training programme significantly improves the postural stability in male hip OA patients.

Keywords:

• postural control
• hip
• osteoarthritis (OA)

Introduction

Osteoarthritis (OA), especially in knee and hip joints, is one of the most common and acute diseases of the motor system, particularly among elderly people [1],[2]. Frequency of hip and knee OA varies among patients from different countries [3]. There are about 8million OA patients in Poland, among whom 40% with hip OA [4].

The symptoms of hip and knee OA, such as pain and joint stiffness, lead to impaired muscle strength of the limb and restricted range of joint motion [5],[6]. Those factors may also cause mobility restrictions, especially among elderly patients, and also lead to significant balance impairment and walking deficiencies [7]. Earlier studies have demonstrated that postural control and proprioception is worse in the knee OA patients than in healthy control subjects [8-10]. As the decreased muscle strength and the impaired balance are significant risk factors in causing falls in elderly patients, it is important to study balance especially in hip OA patients [11],[12].

Postural control is based on sensory system, skeletal muscle and central nervous system [13],[14]. It is being suggested that decrease in muscle strength, hip and knee extensors' mass, hip OA proprioception impairment, as well as the loss of the joint-position sense after a total hip replacement, cause the increase in postural sways and standing stability impairment [15],[16].

Some of the earlier studies proved that functioning of the impaired joint can be significantly improved by proper treatment and training programmes, which lead to standing balance improvement in OA patients [17-19]. However, there are also studies that did not prove the influence of training programmes over the improvement of standing balance [20]. Jarnlo and Thorngren demonstrated that even about two years after a hip fracture, patients still produced more postural sways than healthy controls [21]. Because of insufficient data concerning the impaired standing balance in hip OA patients and the influence of physiotherapy training programmes over this function, we have decided to analyse this issue and present the results of our preliminary studies.

The aim of the study was to analyse balance in elderly men with hip osteoarthritis, and examine the influence of a physiotherapy training programme on balance improvement. We hypothesized that hip OA patients have poorer standing balance than their age- and sex-matched healthy controls, and that our comprehensive physiotherapy training programme in hip OA patients significantly improves their postural stability.

Methods

Body balance in an unrestrained standing position was assessed in 80 males (research with hip OA, who were treated at the Rehabilitation and Prophylaxis Centre ‘Creator’ in Wrocław, Poland). The inclusion criteria encompassed ability to walk and stand independently and general independence in living. The exclusion criteria included a history of neurological, cardiovascular or cerebrovascular disease, neuromuscular disorder, and rheumatoid arthritis. In addition, the subjects were excluded if they were receiving medications known to affect balance. The age of the research group ranged from 60 to 75 years −68.5 ± 3.7, height 169.6 cm ± 6.8 cm and body weight 75.7 kg ± 9.4 kg (mean ± SD). All had been diagnosed with hip coxarthrosis about four years before the beginning of the study. These were people with significant mobility range restrictions in the diseased joint, experiencing great pain. Before the physiotherapy training programme hip average mobility of OA subjects was as follows: flexion 73.9 ± 13.9; extension 7.5 ± 5.3; abduction 21.3 ± 8.1; adduction 11.0 ± 4.8; external rotation 17.9 ± 7.2; internal rotation 13.9 ± 6.1. They were all sent for treatment by GPs and they had all consulted an orthopaedist.

Postural stability tests were performed before and after the rehabilitation. The kinesitherapy covered unloaded active exercises, unloaded active exercises with resistance and postisometric muscles relaxation. The applied physiotherapeutic treatment and massage increased the effectiveness of the performed exercises, which resulted in the painless and broader range of movement for a longer period of time, with more load. The physiotherapy included topical cryotherapy, diathermy and laser. The massage aims at relaxation of hypertension muscles and pain ailments, and is often used before kinesytherapy. The rehabilitation procedures were taking place 5 times a week (from Monday to Friday) for 6 weeks.

Thirty selected healthy, age-matched 60–75-year-old (69.3 ± 3.2) men were used as controls. The controls were sampled from the population register among men living in Wrocław. None of the controls experienced hip pain or functional impairments. The subjects' height was 172.3 cm ± 5.1 cm, and body weight 74 kg ± 7.5 kg. The exclusion criteria for the control subjects were the same as for OA patients.

The pedometer used in this study was manufactured by Medicapteurs (France). The movement of the CPF was analysed.

Postural stability of each subject was assessed in two tests (20s/each test) during which the patient would stand with eyes open on a force plate, first before the physiotherapy intervention and second after it. During each test the centre point force (CPF) and time series were recorded in the sagittal (AP) and frontal (ML) planes for subsequent analysis which involved computation of traditional measures of the CPF variability: range, standard deviation, mean velocity, and area sway.

The subjects' body sway was measured in the morning in a testing area with constant temperature, humidity, and lighting. They wore comfortable clothing and socks but no shoes when standing on the force platform. The subjects stood on the force plate with their hands lying by their side, knees extended and heels approximately 10 cm apart.

Statistical computations were performed using Statistica 5.0. In order to compare the results of postural performance trials (CPF parameters) of hip OA patients with the results of healthy subjects, descriptive statistics (mean ± SD) based on ANOVA has been used. A t-test for dependent trials has been used to assess the differences before and after the therapy. The level of significance was set at p = 0.05.

Results

Table 1 andFigure 1 present the descriptive statistics of CPF variability measures in both planes movement with eyes open.

Figure 1. An example of a stabilographic curve. x - time, y - tension.

Table I.  Descriptive statistic of variables of interest (means ± SD) derived from centre-of-pressure measurements.

Plane Therapy	Anteroposterior		Mediolateral
	Before	After	Before	After
Range (mm)	26.2 ± 11.8	10.7 ± 9.5^☆☆	22.0 ± 10.7	10.1 ± 12.7^☆☆
Area (mm^2)	65.8 ± 24.2	14.8 ± 17.4^☆☆	31.0 ± 19.3	13.1 ± 13.9^☆☆
Mean velocity (mm/s)	89.8 ± 43.3	44.1 ± 25.0^☆☆	65.4 ± 29.9	33.1 ± 46.4^☆☆
Standard deviation (mm)	6.0 ± 2.7	2.3 ± 1.9^☆☆	4.96 ± 2.5	2.1 ± 2.5^☆☆

^☆☆p < 0.01.

There were significant differences between the two trials before and after the physiotherapy training programme in all CPF variability measures: range, standard deviation, mean velocity, and area sway in both sagittal and frontal plane. Moreover, there were significant differences between hip OA patients (after therapy) and healthy control subjects in all CPF parameters in both planes.

Discussion

We hypothesized that hip OA could contribute to a decrease in standing balance abilities and that physiotherapy training could improve postural stability in hip OA patients.

The performed tests showed males with hip OA characterized by the lower standing balance ability in comparison to the healthy males.

The tests conducted after the rehabilitation showed clear improvement of the body stability of the hip OA patients, illustrated by a significant decrease in the values of the examined parameters. The improvement of the results occurred in the sagittal and frontal plane. However, these differences result from conditions of maintaining balance in these planes.

The disorders of the maintaining balance process in the subjects with coxarthrosis may be caused by the change of anatomical and mechanical characteristics of the diseased joint. The progressing pathological process leads to degenerative changes of the femoral head, cotylid cavity of the hip joint and the size of the neck-shaft angles and antetorsion angle of the femoral head-neck. Biomechanical changes described above, resulting from the progressing degenerative process of the hip joint, lead to alterations in the tension of the capsulomusculoligamentous system and in consequence to pelvic stability disorders. They also cause body balance impairment and acute pain, forcing the patient to seek the least painful body position [11],[12]. Therefore, it may be thought that the disorders in the process of maintaining the standing stability in the examined patients are an effect of the observed stato-dynamic changes in the hip joint.

Postural control requires coordinated muscle action [22]. Our earlier results demonstrate that men with hip OA have significantly lower adduction, abduction and flexion muscle strength, and range of the joint motion than their age- and sex-matched controls [23]. Additionally, both the decrease of muscle size and pain lead to the decrease of muscle strength in hip OA and impaired balance. We showed that our physiotherapy training programme – thanks to the muscle strength improvement, increase of the mobility range, relaxation of the overstretched muscles and decrease of pain, decreased postural sways and improved postural stability.

Most studies on postural control have focused on the knee joint, whereas little information is available about the hip joint, and about physiotherapy influence on postural stability in hip OA patients. In studies of rheumatoid arthritis patients, Tjon at al. reported an 80% decrease in stability of rheumatoid arthritis patients. Several groups have reported that knee OA patients exhibit a decrease in postural stability [8],[24]. However, Jari et al. showed that hip OA patients do not have any standing balance deficit [25].

Song et al., using a specific tai-chi training programme in order to assess the improvement of physical functions in OA patients, demonstrated improvement of balance, decrease of joint stiffness and increase of abdominal muscle strength [26]. Suomi and Koceja used an aquatic exercise intervention programme in lower limb OA patients and proved significant decrease of side sways and area sways and the improvement of sagittal-lateral sway rate [27].

Prophylaxis is important for the treatment of coxarthrosis. Proper prophylaxis should involve all means and measures aimed at maintaining the patients in good health: healthy lifestyle, proper nutrition, systematic and rational relaxation and adjusting work place conditions to the human body's physiological needs. It should also be underlined that systematic physical activity connected with a suitable exercises selection of improves fitness, and to a considerable degree, body stability [12],[13].