Stor studie om det aller meste rundt forskjellige diagosekriterier og individuelt det er fra terapeut til terapeut, men også fra studie til studie.
Shoulder pain and dysfunction are common in the general population. A systematic review reported point prevalences for shoulder pain ranging from 7% to 26% with some indication that prevalence increases with age (Luime 2004a). Data from the US National Ambulatory Medical Care Survey (NAMCS) 1993 to 2000 indicate that one per cent of all office visits to physicians are for shoulder pain, and that a quarter of these visits are to primary care physicians (Wofford 2005). Moreover, shoulder pain has little tendency to resolve quickly or completely; according to a Dutch study, one half of all sufferers still report problems a year after their initial consultation (Van der Heijden 1997).
Impingement was originally characterised by Neer and Welsh (Neer 1977) as pinching of the soft-tissue structures between the humerus (upper arm bone) and the bone-and-ligament coraco-acromial arch of the scapula (shoulder blade) on movement. These structures include the contents of the so-called subacromial outlet: the ‘rotator cuff’ of muscles and tendons that surrounds the shoulder joint and the large lubricating sac (the subacromial bursa) that overlies it; and also the biceps tendon, which arches over the humerus, deep to the rotator cuff and within the shoulder joint itself. Neer 1977 proposed a continuum of impingement severity, from irritation of the bursa and cuff (normally due to overuse, and reversible by conservative management) to full thickness tears of the cuff. It has since been theorised that any abnormal reduction in the subacromial outlet’s volume (e.g. by bone shape, soft-tissue thickening, posture or minor joint instability) may predispose to, contribute to, perpetuate or aggravate this train of events (discussed by Hanchard 2004).
When a person presents with a history and symptoms suggestive of shoulder impingement, the clinician performs a series of physical (non-invasive) tests that aim to establish the diagnosis, and inform treatment and prognosis. Such tests may include the ‘painful arc’ test, intended to identify impingement in general terms (Cyriax 1982); tests to identify subacromial impingement (e.g. Neer 1977) or internal impingement (e.g. Meister 2004); tests to differentiate subacromial from internal impingement (Zaslav 2001); tests to diagnose rotator cuff involvement, including tears (e.g. Gerber 1991a; Gerber 1996; Hertel 1996a), or biceps tendon involvement (e.g. Yergason 1931); or tests to diagnose glenoid labrum tears (e.g. Kim 2001; Liu 1996b; O’Brien 1998a). These tests are described in Table 1, and include tests that were identified in studies included in this review.
Physical tests involve clinical and interpretative skills, and results have been shown to differ with testers’ expertise (Hanchard 2005). This has implications for the generalisation of results relating to test performance from individual studies.
Other tests, usually conducted subsequently and in secondary care settings by specialists, include ultrasonography, arthrography, bursography, magnetic resonance imaging (MRI) and magnetic resonance arthrography (MRA). Those considered as potential reference standards for this review are described in Table 3. Some of these tests are invasive and none is completely valid (Dinnes 2003). Specifically, the generally accepted gold standard of diagnosis, direct observation at open or arthroscopic (‘keyhole’) surgery (Table 3), is not completely valid because tears within the substance of the rotator cuff are not directly visible (Fukuda 2003) and conversely, visible tears may be asymptomatic (Dinnes 2003; MacDonald 2000a; Milgrom 1995; Sher 1995). Surgery carries a risk of complications (Blumenthal 2003;Boardman 1999; Borgeat 2001), and is not applicable in the primary care setting where the majority of consultations and treatment prescriptions occur. Moreover, approximately 70% of patients with shoulder impingement respond to conservative treatment (Morrison 1997a) and so those having surgery cannot be considered representative (spectrum bias).
Whether intentional or unintentional, variations in index tests’ procedure or interpretation were prevalent, such that, as observed above, there were only six instances of any index test being performed and interpreted (in terms of criteria for, and implications of, a positive result) similarly in two studies; and no instances of three studies or more using any one test similarly.
Few studies addressed this aspect, although it is fundamental to the validity of clinical tests. Agreement is best evaluated using the kappa coefficient, since this takes account of the fact that agreements may occur by chance. The coefficient ranges from 0 to 1, and interpretation has been recommended as follows by Altman 1991: less than 0.20 = poor; 0.21 to 0.40 = fair; 0.41 to 0.60 = moderate; 0.61 to 0.80 = good; 0.81 to 1 = very good. By these criteria, and based on point estimates, very good between-rater agreement was achieved for only one test, the biceps load II test (Kim 2001). Good agreement was obtained for the passive compression test (Kim 2007b) and resisted lateral rotation from neutral rotation (Michener 2009). Agreement for the painful arc test was moderate (Michener 2009), while that for Neer’s test was fair to moderate (Michener 2009; Razmjou 2004). For the empty can test (Michener 2009) and Hawkins’ test (Michener 2009; Razmjou 2004), agreement was only fair.
There is insufficient evidence upon which to base selection of physical tests for shoulder impingements, and local lesions of bursa, tendon or labrum that may accompany impingement, in primary care.The large body of literature revealed extreme diversity in the performance and interpretation of tests, which hinders synthesis of the evidence and/or clinical applicability.