Background: Conflicting theories exist about the underlying cause of chronic subacromial pain in the middle-aged population. We aim to improve our understanding of kinematics and muscle activation... Show moreBackground: Conflicting theories exist about the underlying cause of chronic subacromial pain in the middle-aged population. We aim to improve our understanding of kinematics and muscle activation in subacromial pain syndrome to provide insight in its pathophysiology. Methods: In a cross-sectional comparison of 40 patients with subacromial pain syndrome and 30 asymptomatic controls, three-dimensional shoulder kinematics and electromyography-based co-contraction in 10 shoulder muscles were independently recorded. Glenohumeral and scapulothoracic kinematics were evaluated during abduction and forward flexion. Co-contraction was expressed as an activation ratio, specifying the relative agonistic and antagonistic muscle activity in each muscle. Findings: During abduction and forward flexion, the contribution of glenohumeral motion to elevation and glenohumeral external rotation was lower in subacromial pain syndrome (at 1200 abduction: - 9 degrees, 95% CI -14 degrees- -3 degrees; and - 8 degrees, 95% CI -13 degrees -3 degrees, respectively), and was compensated by more scapulothoracic motion. The pectoralis major's activation ratio was significantly lower (Z-score: -2.657, P = 0.008) and teres major's activation ratio significantly higher (Z-score: -4.088, P < 0.001) in patients with subacromial pain syndrome compared to the control group. Interpretation: Reduced glenohumeral elevation and external rotation in subacromial pain syndrome coincided with less teres major antagonistic activity during elevation. These biomechanical findings provide a scientific basis for intervention studies directed at stretching exercises to reduce glenohumeral stiffness in the treatment of subacromial pain syndrome, and teres major strengthening to improve humeral head depressor function. Show less
The shoulder joint is a frequent anatomic site of musculoskeletal pain. Most middle-aged adults with shoulder pain have been diagnosed with subacromial bursitis, or subacromial impingement syndrome... Show moreThe shoulder joint is a frequent anatomic site of musculoskeletal pain. Most middle-aged adults with shoulder pain have been diagnosed with subacromial bursitis, or subacromial impingement syndrome. Attrition underneath the acromion have been presumed to cause painful inflammation of subacromial tissues for years, but scientific evidence was limited. The real cause for subacromial pain is still unknown, which resulted in the diagnostic label “subacromial pain syndrome”. In this thesis, we focused on the effectiveness of acromioplasty in the treatment of patients with subacromial pain. We found no effect of acromioplasty over bursectomy alone on long-term shoulder pain and function. We also examined shoulder kinematics and muscle activation in patients with subacromial pain. We found an association between the size of rotator cuff tears as well as subacromial pain syndrome with shoulder kinematics, and described an increase in teres major muscle activity in subacromial pain syndrome. The project contributed to changed recommendations in guidelines regarding the treatment of subacromial pain syndrome. Our kinematic and biomechanical studies may create a biomechanical rationale for physiotherapeutic strategies targeted at the teres major muscle in the treatment of subacromial pain. Show less
Objective To identify prognostic factors for the effectiveness of needle aspiration of calcific deposits (NACD) for rotator cuff calcific tendinitis (RCCT) Methods One hundred forty-nine patients... Show moreObjective To identify prognostic factors for the effectiveness of needle aspiration of calcific deposits (NACD) for rotator cuff calcific tendinitis (RCCT) Methods One hundred forty-nine patients with symptomatic RCCT were included in a prospective cohort study. Pain (VAS), shoulder function (SST and DASH), and quality of life (EQ-5D) were assessed at baseline and at 3, 6, and 12 months post-NACD. Univariate analyses (independent t tests or Mann-Whitney U tests depending on the distribution of data) were performed to build a multivariable linear regression model. Stepwise regression analysis through backward elimination was performed to evaluate the effect of predefined prognostic factors on the outcome. Results Patients who underwent multiple NACD procedures had less reduction of pain (p < 0.01). Furthermore, a larger reduction in VAS pain scores at 3 months post-NACD was associated with a larger reduction in VAS pain scores at 12 months (p < 0.01). More improvement of SST and DASH scores at 3 months was associated with better SST, DASH, and EQ-5D scores at 12 months (p < 0.01). Smaller-size calcific deposits were associated with less improvement of DASH (p = 0.03) and EQ-5D scores (p = 0.01). A longer duration of symptoms prior to NACD was associated with less improvement of EQ-5D scores (p = 0.01). Conclusions A good initial response after NACD is associated with better outcomes at 12 months. Patients with a longer duration of symptoms prior to NACD and patients who require multiple procedures showed inferior outcomes in terms of pain reduction and improvement of quality of life. Smaller-size calcific deposits are associated with a less favorable outcome of shoulder function and quality of life scores and might therefore be less susceptible for NACD. Show less
The Subacromial Impingement Syndrome (SIS) is the most prevalent disorder of the shoulder in primary health care. Acromionplasty, as the main surgical treatment of SIS, is one of the most performed... Show moreThe Subacromial Impingement Syndrome (SIS) is the most prevalent disorder of the shoulder in primary health care. Acromionplasty, as the main surgical treatment of SIS, is one of the most performed orthopedic surgeries. However, its results are highly variable. Possibly, there are different etiologic subgroups of patients, that might need specific treatment approaches. Several etiologic mechanisms have been described for subacromial narrowing or __impingement__: i.e. 1) structural causes, including acromion shape, subacromial bony spurs, osteophytes; 2) narrowing of the subacromial space due to humerus cranialisation in patients with (micro)instability, or scapular dyskinesia; 3) intrinsic mechanisms such as primary degenerative tendinopathy of the rotator cuff. The aim of this thesis is to unravel the clinical entity __Subacromial Impingement Syndrome__ and to develop methods for identifying distinct etiological patient subgroups that need specific diagnostics and treatment strategies. To this end, we explore the terminological problems and opinions on the main characteristics of SIS amongst international health practitioners, study the prevalence of previously reported etiologic mechanisms in patients with SIS symptoms, develop clinical and biomechanical methods to evaluate and categorize patients with SIS symptoms in diagnostic subgroups, and compare treatment outcomes in trials and follow-up studies. Show less
Witte, P.B. de; Zwaal, P. van der; Arkel, E.R.A. van; Nelissen, R.G.H.H.; Groot, J.H. de 2014
We hypothesized that shoulder pain, caused by rheumatoid arthritis (RA), can lead to disuse of the affected shoulder joint. In addition to the structural changes caused by rotator cuff tears,... Show moreWe hypothesized that shoulder pain, caused by rheumatoid arthritis (RA), can lead to disuse of the affected shoulder joint. In addition to the structural changes caused by rotator cuff tears, tendonitis or synovitis disuse may play an important role in the aetiology of fatty degeneration (FD) of the rotator cuff muscles. This FD may induce proximal migration due to shoulder muscle force imbalance, causing even more pain due to subacromial impingement. FD is thought irreversible, even when the underlying pathology was treated. Early referral and treatment of shoulder involvement of rheumatoid disease may protect the rheumatoid shoulder from this downward spiral. It is of great importance to screen rheumatoid arthritis patients for shoulder joint involvement at an early stage. The use of the Upward migration Index to assess proximal migration can be used reliably to screen for the presence of rotator degeneration. In order to quantify fatty degeneration we advocate using the Mean Muscle Density measured on CT-images. We underline the importance of these measurements as they were strongly correlated to shoulder pain and functional loss. Measurement of proximal migration in an early stage can therefore play an important role in the initiation of functional and medicinal treatment of RA and may present patients with better possible outcome providing that shoulder surgery is indicated. Show less
