Technological rehabilitation versus conventional rehabilitation following hip replacement: A prospective controlled study

1. Introduction

Total hip arthroplasty (THA) is one of the most commonly performed orthopedic operations in the world. Osteoarthritis that does not respond to pharmacological and conservative treatments is one of the main indications for hip replacement. The number of hip replacement operations continues to grow on account of an increasingly older population, a reduction in the average age of the treated population and higher quality of life expectations [1].

Osteoarthritis, the most common rheumatic joint disorder, affects many different body parts, causing pain, stiffness and reduced function and health status [2]. However, irrespective of the improvement attained in both pain and function following a hip arthroplasty, a patient’s quality of life will remain lower than that of healthy adults; the persistence of functional limitations can be caused by a reduction in proprioception, which is the inevitable result of the disease, which is in turn exacerbated by surgery [3, 4].

It is unclear whether the proprioceptive deficit that accompanies degenerative joint disease derives from or contributes to the etiology of the pathological process. However, the disruption of muscle and joint mechanoreceptors caused by physical trauma results in a partial deafferentation of the joint and surrounding musculature and a consequent reduction in proprioception. The surgery subsequently exacerbates this deficit by removing anatomical parts that are rich in proprioceptive receptors and owing to the presence of postoperative pain and periods of immobility that precede and follow the surgery.

Proprioception is defined as the awareness of limb position and movement [5]. It is the sum of joint position sense (static aspect) and kinaesthesia (dynamic aspect). It is thus a prerequisite for balance control, body orientation and coordination of movements [6]. Until the last decade of the twentieth century proprioceptive rehabilitation was only added as the last stage in a retraining programme. This was probably due to a lack of knowledge regarding the physiological mechanisms that regulate proprioception, as well as possibly the belief that proprioception would reappear spontaneously during conventional rehabilitation sessions without the need for any specific retraining.

Recently, new technological proprioceptive rehabilitation systems are being tested, with the intent to focus on the presence of some form of biofeedback [7]. By providing visual and verbal feedback during rehabilitation, patients can be made aware of their movements and can receive instantaneous feedback to modify movement patterns, thereby avoiding repetition of errors and facilitating limb functional recovery. The physiotherapist can consequently monitor and, if required, modify the rehabilitation treatment according to any progress made or difficulties encountered by the patient.

Few studies have instead been published on the effectiveness of proprioceptive rehabilitation, even of the technological type, after THA [8].

Given this background, our hypothesis is that a technological proprioceptive rehabilitation that combines visual feedback and conventional rehabilitation may be more effective than conventional rehabilitation alone in balance recovery. The aim of this study was to evaluate technological proprioceptive rehabilitation (using proprioceptive platforms) compared to conventional rehabilitation after THA. Moreover, a comparison of the instrumental static and dynamic balance between patients and healthy subjects was performed.

2. Materials and methods

3. Results

4. Discussion

Our study shows that rehabilitation treatment significantly improved static balance in all our patients who underwent THA. Indeed, the stabilometric variables approached normal values in both groups treated (TG and CG). However, in CG the trunk stability worsened after treatment, demonstrating that even after conventional treatment the trunk fails to recover the stability. In TG a greater improvement in static stability parameters was observed mainly in the CE condition, suggesting a considerable improvement of the proprioceptive sensitivity of patients, for which the visual stimulus is no longer necessary to maintain the stability in standing condition. Moreover, the dynamic balance significantly improved in TG: the dynamic instrumental assessment after treatment showed an improvement in the dynamic stability index in all directions only in technological group. Then our results suggest that technological rehabilitation after THA improves both static and dynamic balance, while conventional treatment improves static balance alone. As we hypothesized before the study, technological treatment results in better proprioceptive control. This result may be explained by the fact that balance and proprioception are closely related. The improvement in performance in the CE condition in our sample is a further confirmation of lower limb proprioceptive recovery. Indeed, other authors previously underlined that the hip and the knee joint play an important role in balance control in the CE condition; while the ankle joint plays the most important role in posture and balance maintenance in the OE condition [16].

In the last years, some studies are available on alterations in proprioception in subjects who have undergone THA. Post-surgical rehabilitation programs after THA should, according to current literature [17, 18, 19], be started as early as possible to prevent complications, which include deep vein thrombosis and luxation [20], to reduce pain levels, to recover joint movements [21], muscle strength [22] and tissue elasticity, to start weight bearing early, thereby achieving correct and pain-free deambulation by gradual weaning from aids. Treatment approaches can vary with regard to the frequency of care, functional activities, exercises conducted and timing: pre-surgical or post-surgical [23]; early and intensive or long-term; in a dedicated centre or at home; in group or individual rehabilitation [24, 25, 26].

Some researchers studied balance in THA patients using proprioceptive platforms after a technological rehabilitation training: some studies reported CoP trajectories using posturography early postoperative [27, 28, 29], while others propose a long-term follow-up [30, 31]. Moreover, a recent meta-analysis investigated pain, risk of falls and quality of life related to balance and proprioceptive training on total hip and knee replacement [32]. Just few data are available about dynamic stability after hip replacement [33, 34, 35] but no one reports data about technological rehabilitation. At the present no research presents simultaneously the study of dynamic stability after technological rehabilitation treatment in patients with total hip replacement.

The higher improvement in our sample using the technological rehabilitation may also be ascribed to the fact that the therapist can follow the patient during rehabilitation more effectively, as well as correct any errors made by the patient and change the rehabilitation treatment according to progress or regression in order to optimize functional recovery. This type of rehabilitation can also be used to quantify improvements and the intensity of motor training; it allows the therapist to use a wide range of exercises, thereby improving compliance, as well as other technological systems, such as videogames. The most effective exercises are those performed when the platform is mobile. Indeed, platform instability provides continual alterations in balance, forcing the muscles and nervous system to keep adjusting themselves in order to maintain body balance. Consequently, the brain receives a continuous flow of kinesthetic information that improves proprioception, kinesthetic sensitivity and balance control. This type of rehabilitation also provides visual biofeedback that makes the patients aware of their movements and consequently allows them to modify their movement patterns accordingly.

In conclusion, our results suggest that rehabilitation after THA improves static balance. When proprioceptive technological rehabilitation is combined with conventional rehabilitation, an improvement in dynamic balance is also observed.