30th May 2011
“Scapular positioning and movement: a clinical perspective”
PhD thesis Filip Struyf
Vrije Iniversiteit Brussel, Faculty of Physical education and Physical Therapy
Shoulder pain is the third most common musculoskeletal disorder in general practice, after low back pain and neck pain (Weevers et al., 2005), with lifetime prevalence figures up to 67% (Luime et al., 2004). There is evidence suggesting that scapular positioning is abnormal in patients with musculoskeletal disorders like shoulder impingement syndrome (Ludewig & Cook 2000, Hébert et al. 2002, Cools et al. 2003), atraumatic shoulder instability (von Eisenhart-Rothe et al. 2005), multidirectional shoulder joint instability (Illyés & Kiss 2005), and shoulder pain after neck dissection in cancer patients (van Wilgen et al. 2003, van Wilgen 2004). Although assessing the scapulothoracic motion is considered an essential component of shoulder evaluation, clinical assessment of scapular motion has proven challenging because of both the extensive soft tissue covering the scapula and the complex 3-dimensional patterns of motion that occur.
The following research questions were addressed in the PhD thesis:
What is normal and abnormal scapular positioning and movement?
Understanding three-dimensional motion of the scapula is a foundation for understanding motion-related abnormalities. Unless normal scapular motion is well understood, we cannot recognize and treat scapular motion abnormalities, or interpret clinical examination findings. Our review concluded that during shoulder elevation in asymptomatic subjects, the scapula rotates upwardly, rotates externally, and tilts posteriorly. In addition, in patients with shoulder impingement syndrome, the scapula demonstrates a decreased upward rotation and a decreased posterior tilt. Finally, in patients with glenohumeral shoulder instability, the scapula demonstrates a decreased scapular upward rotation and consequently a significantly increased internal rotation. Although we could provide moderate consensus on scapular external rotation during humeral elevation, some still question this consensus (Ludewig & Reynolds, 2009). Ludewig & Reynolds (2009) suggest that slight increases in scapular internal rotation may be normal early in the range of arm elevation in scapular plane abduction and flexion. This finding was also reported by Braman et al. (2009). They concluded that until 125° of glenohumeral elevation, the scapula internally rotated and then externally rotated with further elevation (Braman et al., 2009). Some studies also reported some downward rotation during the first degrees of shoulder elevation.
Can we clinically examine scapular positioning in a reliable manner? Our primary interest was the reliability of a standardized observation protocol and 2 clinical tests for the assessment of scapular positioning and movement in healthy musicians. Our results demonstrated that visual observation of the scapula is a reliable tool for screening prominence of the medial scapular border (winging) and prominence of the inferior scapular angle (tilting) during unloaded movement in healthy musicians. However, these data were only gathered from healthy participants. Therefore, the use of this clinical assessment tool remains limited to screening healthy musicians and the development of preventive exercise programs. However, recent literature suggests not to rate the scapula with a selected deviation (winging, tilting), but to classifying scapular motion as normal, subtle dyskinesis, or obvious dyskinesis (McClure et al., 2009).
Does scapular positioning differ between children and adults? This study has attempted to provide clinicians with data for interpreting clinical tests when assessing scapular positioning and motor control in adults and children. Our findings suggest that the clinical assessment protocol, and more specific the measurement of scapular upward rotation and forward shoulder posture, are able to discriminate between children and adults: therapists can use these clinical tools in both children and adults. One of the major conclusions of this chapter addresses the greater scapular upward rotation in children than in adults. We suggest that with an increasing thoracic kyphosis, scapular upward rotation gets restricted.
Can we discriminate patients with shoulder pain from unimpaired subjects using a clinical assessment protocol for scapular positioning?
Although the clinical assessment protocol was not able to identify statistically significant differences in scapular positioning or motor control between athletes with or without shoulder pain, there appear to be some significant differences between the athletes’ symptomatic and asymptomatic shoulder. First, tilting appears to be more prevalent on the painful side. When comparing dominant versus non-dominant shoulder, this difference reoccurred significantly. Apparently, scapular tilting is dominance related, rather than pain related. Second, this study also addressed scapular motor control. The KMRT showed some strong significant differences between the painful shoulder and the pain free shoulder within the athletes with shoulder pain. However, this difference was not dominance related, but rather pain related, which emphasizes the relation pain-motor control.
Can we identify risk factors, i.e. scapular characteristics that predict the onset of shoulder pain in overhead athletes?
As no longitudinal study has been reported, it was unknown whether abnormal scapular positioning is predictive for shoulder pain. Our 2-year follow-up study was the first to investigate the possible influence of scapular positioning and scapular dynamic control in the development of shoulder pain in recreational overhead athletes. It was found that after 2 years, 22% of our athletes had developed shoulder pain. This comes as no surprise, given the high risk of overhead athletes to develop shoulder disorders. However, scapular characteristics did not predict the occurrence of shoulder pain in our overhead athlete population. Although the amount of observed winged scapulas in the athletes that presented with shoulder pain was substantially higher than in the pain-free cohort, the cause-and-effect relation remains to be established.
Can we treat patients with shoulder impingement syndrome using a scapular oriented approach?
In order to investigate the effectiveness of a scapular oriented treatment approach in patients with shoulder impingement syndrome, we conducted a randomized controlled clinical trial. The scapular oriented treatment approach focused on the treatment of scapular dyskinesis. The main contribution of this study is to propose an exercise program, based mainly on scapular motor control principles, that provides improvement in shoulder disability and pain. The intervention proposed in this study includes shoulder control exercises targeting the specific impairments described in patients with SIS. This study demonstrated a strong clinically significant effect in favor of the scapular focused approach.