Nowadays, the post-operative rehabilitation approach in the treatment of total hip arthroplasty (THA) is applied earlier and is multidisciplinary [1]. Protocols that involve an accelerated and intense physiotherapy intervention enable patients to achieve earlier functional autonomy thus reducing hospitalization time [2–4]. The literature descriptions of the autonomy achieved by patients at discharge from hospital are very heterogeneous [5–7] and often without specific measurement scales and limited to the measurement of single performances such as the ability to walk independently. A complete measurement of the autonomy achieved, however, plays a central role to show precisely the results obtained by early rehabilitation [8]. Several scales measure the autonomy of the patient, as the “Functional Independence Measure” (FIM) [9] and the “Barthel Index” (BI) [10]. These scales, however, include items like feeding, bowels and bladder function, which do not seem relevant for acute patients after joint arthroplasty. The “Iowa Level of Assistance” (ILOA) [11] scale seems more adequate to evaluate the outcome of the early rehabilitation treatment. Assessing 5 functional activities, this scale providesa more complete information about patients’ autonomy. Other commonly used testsget information only about a specific aspect of walking as endurance (e.g., Six-minutes walk test) [12] or gait speed [13–15]. Different authors have used the ILOA scale to measure the early results and to evaluate the efficacy and the optimal intensity of the rehabilitation treatment [16, 17] or the influence of different surgical techniques [18, 19]. The factors that significantly influence the autonomy achieved, however, have not yet been fully explained. Vincent el al. [20], in a retrospective study on 332 THA patients, considered different possible prognostic factors and found that only gender and age were significant. The aim of this study was to determine the mean level of autonomy achieved by patients undergoing total hip arthroplasty at discharge from hospital using the ILOA scale as a measurement tool and to investigate the possible prognostic factors of this autonomy.

A prospective study was performed on consecutive primary THA patients following chronic joint disease, between January and May 2012 at department of “Orthopaedic-Traumatology and Prosthetic surgery and revisions of hip and knee implants” of the Rizzoli Orthopaedic Institute, where the postoperative rehabilitation program was implemented. The rehabilitation program for the joint arthroplasty following fractures, revision surgery, and partial replacement differs from the standard, therefore these conditions were excluded from the study. Furthermore, in order to obtain as uniform a sample as possible, patients with concomitant neurologic diseases (Parkinson’s disease or pre-surgery stroke) and rheumatologic diseases (rheumatoid arthritis or ankylosing spondylitis) or postoperative complications that do not allow to continue the rehabilitation program (severe anemia, cardiac problem as acute myocardial infarction, respiratory problems as lung infection) with a hospitalization of more than 7 days were excluded. Institutional review board approval was obtained from the Ethics Committee of the Rizzoli Orthopaedic Institute before conducting this study.

One hundred eighty six patients were eligible for this study. 19 patients were excluded having a length of stay superior on seven days. The medical records confirmed that they all had postoperative complications: 9 cases for hemorrhagic anemia, 4 cases for cardiac problems, 3 cases for respiratory problems, 1 case for wound infection, 2 cases for other reasons. Among this group the evaluation of the comorbidities identified 53 % of patient with ASA score > 2.

The aim of the study was to measure the level of autonomy at discharge using the ILOA as a measurement scale and assess any predictive factors. The population enrolled in the present study showed a good level of autonomy. This level was slightly greater than the level reported by Stockton and Mengersen [16], who found a mean score of 18.2 (±7.7) at the ILOA Scale measured on the 6th day. However, the patients assessed by Stokton and Mengersen [16] were slightly older (the mean age was 68.3 years) and with a smaller percentage of women (43.3%).

When studying the postoperative rehabilitation course, Zavadak et al. [8] showed variability in achieving the various functional activities by the patients treated by joint arthroplasty. In particular, ascending and descending 3 steps was found to be the most difficult activity compared to the other activities examined, i.e. walking and bed mobility. The data of the present study showed that supine to sit transfers was an important issue for the patient treated by THA, by revealing a correlation with the number of treatment performed. This can be explained by the surgical technique with the postero-lateral approach which entails the partial detachment of the gluteal musculature and therefore causes an initial difficulty in performing the active abduction movement of the hip. The supine-to-sitting item of the ILOA scale seems particularly sensitive in assessing this aspect. Achieving a normal gait speed is one of the most challenging goals after THA. This ability was not considered by Zavadak et al. [8], but several authors suggested that the measure of the speed of walking is important to evaluate the improvement of patients during different stages of the rehabilitation program [14, 15, 24, 25]. In the present study the gait speed recorded at discharge was strongly impaired. This finding is similar to the results of Lawlor et al. [18]. It has been reported that in the first six months there is a significant improvement of the walking speed, which increases up to 0.82 m/s one month after surgery [13], to 0.95 m/s at six weeks [14] and to 1.14 m/s [14] or 1.08 m/s [15] at six months. Normal gait speed is an evolutionary task that is developed through physiotherapy and exercise and requires multiple abilities, as endurance, muscle strength, balance, coordination, weight bearing control. Other factors as pain, edema, postsurgical weakness and medicines can also affect the performance. Inadequate gait speed causes a poor walking efficiency with a high energy loss [13]. The rehabilitative program should improve the control of the centre of mass of the body in order to smooth its vertical displacement during gait and improve the efficiency of this skill [13]. Early post-surgical rehabilitation protocols usually focus on functional skills as walking independence training, weight bearing restrictions, prevention of implant dislocation and daily life activities. Skills as gait speed, symmetry and cadence are secondary goals that are postponed to the post-acute stage of recovery. In the acute setting of care, because of the short time of hospitalization and patient postsurgical clinical condition, the training of gait speed is a secondary goal that actually is mediated by a personal initiative of the physiotherapist. Specific exercises as respiratory training during walking, behavioural graded activity as endurance training and muscle strength and flexibility during function, pain and disability discrimination, posture change pacing [26] in the early physiotherapy treatment could be useful to increase the gait speed at discharge. Further studies are necessary to verify this hypothesis. In agreement with the literature, the multivariate analysis showed that age and gender were significant factors in determining the functional outcome [20]. Elderly women achieved the poorest performance. Conversely, the length of hospitalization and the number of treatments did not seem to influence directly the autonomy achieved. This finding conflicts with the data published by Ganz et al. [27], who showed how, in the period from 1990 to 2000, with a reduction in hospitalization time there was a reduction in the performance at discharge. New surgical techniques and a more intense rehabilitation approach might have enabled an inversion of this trend. All these indications should be considered to develop more and more specific rehabilitation programs that enable patients to achieve better levels of autonomy at discharge from hospital, bearing in mind that elderly women are the type of patients most at risk in this phase of rehabilitation. Limits of the present study are the enrollment of a selected sample and the lack of data about the preoperative functional ability of the patients. However, according to a recent systematic review [28] the ASA Score is the only factor able to influence the length of stay after total hip arthroplasty. Other preoperative patient related factors do not seem to influence the functional recovery. Since the participants enrolled in the present study had similar ASA scores (93 % had an ASA score <3 points), it is unlikely that their baseline characteristics influenced the results.

Using a validated measurement scale to assess patients’ functional performance at discharge from hospital gives an indication of the autonomy achieved by the patient which is comparable with other clinical findings and enables to detect the variability of the results obtained. Gait speed is strongly impaired at discharge. The physiotherapy protocol in the acute phase after the surgery should include gait speed as a skill to reach in order to improve walking ability and efficiency. Age and gender were found to be significant prognostic factors of the levels of autonomy at discharge. These findings should be considered in any project aimed at optimizing an accelerated rehabilitation program after THA.