SACROILIAC JOINT

Sacroiliac joint Stability – ‘Form closure’

the innominate they will tend to produce anterior nominate rotation, thus disen- gaging SIJ self-bracing, unless the joint is pre-emptively stabilised by some dynamic strategy. If one leg is perceived to be heavier, or pain is produced, SIJ stability is enhanced by manual compression of the joint and the active straight leg raise repeated. Resolution of the symptoms indicates the SIJ to be the likely cause.

Nutation

Tensions sacrotuberous ligament Stable Self-locked Self-braced

Figure 6: Form closure Counter nutation

Tensions dorsal SI ligament Unstable Unlocked Unbraced

TREATMENT Rationale of treatment Treatment aims to restore normal function - motion and stability. Motion is moni- tored by active and passive movement tests and stability is monitored through modifications of the passive movement tests and the active straight leg raise test. Treatment attempts to achieve this through optimisation of joint alignment and by improving joint mobility where lacking. Rehabilitation aims to improve motor control and muscle function in maintaining joint alignment and control.

Assessment Assessment aims to identify dysfunction of motion and stability and to identify the nature of the problem in terms of whether it appears to be articular or appears to be perpetuated by myofascial influences.

Figure 7a: Overview of the posterior oblique (left image) and anterior oblique myofascial slings (right image)

Myofascial problems: Myofascial influ- ences such as muscle tightness or exces- sive or overly perseverant muscle activity can distort the posture of the pelvis and joint alignment, causing pain and/or a disruption of joint function. This may in turn perpetuate the muscle dysfunction. Alternatively, it is likely that joint dys- function from, for example, trauma, can reciprocally lead to muscle dysfunction.

Figure 7b: Specific tensions caused by specific muscles to create the slings at the front and back www.sportex.net

Articular problems: Under certain cir- cumstances it is possible for the sacroili- ac joint to move beyond its normal range of movement and be prevented from returning to neutral by the opposition of its rough and convoluted joint surfaces. This may occur under intense load such as a fall or impact, or under normal loads because of a failure of those mechanisms designed to maintain normal alignment. It may therefore be a hallmark of instability. It is paradoxical that an articular joint restriction (a ‘locked joint’) can result from instability. Active movement tests The active movement assessment of the

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