Atraumatic shoulder instability: treatment with physiotherapy
Authors: M Scott, Nottingham (UK)
References: SECEC 2005, Rome
Conservative methods are the first choice of treatment for atraumatic instability of the shoulder (Pollock & Bigliani 1993, p89). The stability of the glenohumeral joint is influenced by the interplay of bony structures, the labrum, the joint capsule, the glenohumeral and coracohumeral ligaments, the joint internal pressure gradient and dynamic muscle contraction (Hawkins & Saddemi 1990, p243; Wang & Flatow 2005, p3). Physiotherapy treatment can therefore exert its influence primarily via alterations in muscle contraction. The function of the shoulder complex and the upper limb is to position the hand in space. The aim of treatment is to optimise the action of the musculature around the shoulder complex, in order to maximise stability of the glenohumeral joint without losing any of this function. Examination often reveals kinematics as the major difference between symptomatic and non-symptomatic shoulders on the same individual. Therefore a physiotherapy programme is aimed at altering symptomatic scapular kinematics to encourage symmetry and stability. Stability comes from sound foundations, and so rehabilitation is encouraged to work from the pelvis outwards (Rubin & Kibler 2002, p34-5), with alignment and control of the trunk and hip muscles. The scapula rotates around the trunk on the strut of the clavicle, and the pectoralis minor should be of adequate length for this to happen (Borstad & Ludewig 2005). Similarly, latissimus dorsi should have sufficient length for full elevation of the arm without lumbar extension or trunk side flexion.
The movement of the scapula is controlled by muscular groups acting as forced couples. Careful attention must be taken to develop synergy within these groups, so that the scapula can maintain congruency with the trunk while positioning the glenoid in an optimal relationship with the humeral head (Hawkins & Saddemi 1990, p244). This can be achieved with mirrors or video, verbal prompts and touch, although some groups also use biofeedback devices. The humerus itself is best kept externally rotated and in, or anterior to, the plane of the scapula, particularly with anterior instability and the early stages of rehab (Lee & An 2002, p45; Labriola et al 2005, p37-8).
The dynamic neuromuscular control training (Wang & Flatow 2005, p5), supported by rotator cuff and scapulothoracic muscle strengthening, helps to adjust the muscle length/tension relationships across the glenohumeral joint (Lee et al 2000, p855) and therefore maximises the concavity/compression element of stability (Lippitt & Matsen F 1993).
1. Borstad JD & Ludewig PM (2005). The effect of long versus short pectoralis minor resting length on scapular kinematics in healthy individuals. JOSPT. 35(4):227-238
2. Hawkins RJ & Saddemi SR (1990). Shoulder instability. Current Orthopaedics. 4:242-252 Labriola JE, Lee TQ, Debski RE & McMahon PJ (2005) Stability and instability of the glenohumeral joint: the role of shoulder muscles. JSES. 14Supp:32-38
3. Lee SB & An KN (2002) Dynamic glenohumeral stability provided by three heads of the deltoid muscle. Clin Orth Rel Res. 400:40-47
4. Lee SM, Kim KJ, O'Driscoll SW, Morrey BF and An K-N (2000) Dynamic glenohumeral stability provided by the rotator cuff muscles in the mid-range and end-range of motion: a study of cadavera. JBJS. 82A(6): 849-857
5. Lippitt SL & Matsen F (1993) Mechanisms of glenohumeral joint instability. Clin Orth Rel Res. 291:20-28 Pollock RG & Bigliani LU (1993) Recurrent posterior shoulder instability diagnosis and treatment. Clin Orth Rel Res. 291:85-96 Rubin BD & Kibler WB (2002) Fundamental principles of shoulder rehabilitation: conservative to postoperative management. Arthroscopy 18(9) Supp 2:29-39
6. Wang VM & Flatow EL (2005) Pathomechanics of acquired shoulder instability: a basic science perspective. JSES. 14 Supp:2-11