Psychosocial factors are frequently present in patients with shoulder complaints and might play a role in the disease, the perception of pain and disability, and the functional outcome after surgery [16]. The chronicity of the complaints often negatively impacts the quality of life and physical and mental well-being. Kinesiophobia, negative pain belief, low pain efficacy, and catastrophizing can be associated with higher levels of pain and disability in the upper extremity problems [9, 25]. Similarly, depression has been associated with worse surgical outcomes in several musculoskeletal conditions and seems to be more prevalent in orthopaedic patients than in the general population [8]. More specifically, in patients with shoulder problems, depression and anxiety can negatively influence health-related quality of life and are associated with higher levels of functional disability and a longer duration of symptoms [5, 22]. Some studies demonstrate worse postoperative outcomes in patients with anxiety and depression, whereas others found no influence of these psychological parameters after shoulder surgery [6, 11, 17, 19].
This study focuses on patients with frozen shoulder, a disabling condition of the shoulder characterized by often severe pain and functional restriction of both active and passive shoulder motion for which radiographs of the glenohumeral joint are essentially unremarkable. Although some patients with a frozen shoulder improve without any intervention, the majority of patients continue to have pain and/or restriction of mobility [26]. Similar observations were made by Abrassart et al. [1]. These authors concluded that the natural history of frozen shoulder often sees short-term improvement but bears a high chance of ongoing low-level restriction and pain. The condition can be primary or idiopathic, or secondary, indicating a specific cause [28]. Treatment options for frozen shoulder include physiotherapy, injections, hydrodilatation, manipulation under anesthesia, and capsular release. Hydrodilatation consists of injecting fluid in the glenohumeral joint under fluoroscopic control to rupture the capsule to increase the shoulder’s mobility [2]. It is an easy, safe, and cost-effective method to treat frozen shoulder in terms of functionality and pain relief [4, 14, 15, 20, 21, 27]. Moreover, when a first hydrodilatation does not result in adequate pain relief and/or restoration of mobilty, the procedure can easily be repeated before proceeding to a surgical procedure.
Clinicians often have the impression that patients with a frozen shoulder have a specific personality and tend to be neurotic, tense and have a low pain threshold. In a previous study, we could not confirm the assertion that such a ‘frozen shoulder personality’ exists [10]. Several studies found that psychosocial factors like depression, anxiety, and kinesiophobia are frequently associated with frozen shoulder [12, 13]. While these studies provide meaningful information about the mental health comorbidity of patients with a frozen shoulder, they are all cross-sectional, which limits the conclusions we can draw about the directionality of effects (i.e., whether depression and anxiety predict objective and subjective frozen shoulder outcomes, or whether these outcomes increase the risk of worse mental health problems, or both).
The present study has two primary aims. First, we wanted to confirm the beneficial effect of hydrodilatation in frozen shoulder patients on objective indices of shoulder functionality and subjective outcomes of pain, mobility, kinesiophobia, depression, and anxiety. We hypothesized that a hydrodilatation would increase the shoulder’s functionality, decrease the pain and that the psychological parameters would negatively influence the outcome. Second, we investigated whether anxiety, depression, and kinesiophobia at baseline negatively predict the objective and subjective outcomes of hydrodilatation at 3-month follow-up, and that worse objective and subjective outcomes of hydrodilation positively predict worse mental health complaints at 3-month follow-up. Specifically, we hypothesized that higher levels of kinesiophobia, depression, and anxiety would attenuate the objective and subjective outcomes of hydrodilation, and vice versa, that improvement in objective and subjective clinical parameters would lead to less kinesiophobia, depression, and anxiety at three-month follow-up.