A study by MacDonald1 to assess the diagnostic accuracy of the Neer and Hawkins impingement signs for the diagnosis of subacromial bursitis or rotator cuff pathosis. He found that the two tests have a high sensitivity, but Specificity and positive predictive values for them were low:
Neer Impingement Test is nonspecific. A variety of other conditions can cause positive test results, including:
Codman, in 1931, was the first to note that many patients with inability to abduct the arm had incomplete or complete ruptures of the supraspinatus tendon, rather than primary bursal problems. In 1972, Neer described impingement syndrome characterized by a ridge of proliferative spurs and excrescences on the undersurface of the anterior process of the acromion, apparently caused by repeated impingement of the rotator cuff and the humeral head with traction of the coracoacromial ligament.
The concept of impingement syndrome has evolved to encompass four types of impingement:
Primary impingement is subcategorized further into intrinsic and extrinsic types. Primary impingement is the classic version and occurs without any other contributing pathology.
Secondary impingement occurs when there is instability of the glenohumeral joint allowing translation of the humeral head, typically anteriorly, resulting in contact of the rotator cuff against the coracoacromial arch.
Intrinsic impingement occurs when the structures passing beneath the coracoacromial arch become enlarged resulting in abutment against the arch, examples of this condition include:
Thickening of the rotator cuff.
Calcium deposits within the rotator cuff
Thickening of the subacromial bursa.
Extrinsic impingement occurs when the space available for the rotator cuff is diminished; examples include:
Acromial fracture or pathological os acromiale.
Osteophytes off the undersurface of the acromioclavicular joint.
Exostoses at the greater tuberosity.
Acromial morphology has been implicated as contributing to impingement.
MacDonald PB, Clark P, Sutherland K: An analysis of the diagnostic accuracy of the Hawkins and Neer subacromial impingement signs. J Shoulder Elbow Surg 9:299–301, 2000. PMID: 10979525
Clinical Tests for the Musculoskeletal System, Third Edition book.
Mark Dutton, Pt . Dutton’s Orthopaedic Examination, Evaluation, And Intervention, 3rd Edition Book.