Sacroiliac joint

An 85-year-old black man is noted to have sclerosis of the sacroiliac joint on routine films for back pain. The radiologist suggests that this might indicate Paget s disease. Workup for this condition reveals minimal involvement of the pelvis and LS spine. How would you treat this patient ... 

Alkylosing spondylids is an inflammatory autoimmune reac-dve arthrids wdth a primary end organ target of the intervertebral Joints and the sacroiliac joint at the hip. The characterisdc features are a bowled spine and inflamed joints. Compared wdth 8% of Caucasians as a w hole, 95% of people wdth alkylosing spondylids have the HLA B27 allele. Unlike many autoimmune diseases, alkylosing spondylids is more common in men and has an early onset betw een 20 and 40 m years of age. 

Alkylosing spondylitis Intervertebral joints and sacroiliac joint Eye inflammations and caudae equinae related neuropathies... 

Sacroiliitis - Inflammation in the sacroiliac joint. SAR - Specific Absorption Rate. 

L Damen, C W Spoor, C J Snijders and H J Stam, Does a pelvic belt influence sacroiliac joint laxity , Clinical Biomechanics, 200217 495-498. 

The Sacroiliac Joint This joint would appear very vulnerable, as the surface of the joint is orientated in the sagittal plane that is to say, in the direction of the largest axial loads. However, the discs are perpendicular to the largest force stream, which makes them more vulnerable to torsional load. The sacroiliac joint is very resistant to torsional load. There is a tight interference fit between the roughened surfaces of the joint, and the mechanism of closure of the sacroiliac joint produces tight apposition of the joint surfaces (Fig. 5). 

There are a number of anatomical differences between children and adults. The paediatric skeleton is more elastic than in adults, particularly around the sacroiliac joints and pubic symphysis which allows greater absorption of energy before the joint and ligaments become disrupted. A high energy impact may cause deformity of the bones rather than the fractures and joint disruption that occurs in adulthood. 

Injuries of the posterior pelvic ring, particularly diastasis of the sacroiliac joint, may be better appreciated on pelvic inlet views which are orientated at 25 in a caudal direction. Outlet views may be useful in appreciating displacement in the vertical plane. 

There maybe fractures of the pubic rami as in Type I. There is further diastasis of the anterior aspect of the sacroiliac joints and these are classically referred to as the open book or spun pelvis type injuries. Sacroiliac diastasis is best assessed by CT. There may be some partial instability on AP compression. In children, there may be fracturing of the adjacent bone rather than ligament rupture. This is a reflection of the relative strength of the ligaments compared with bone in the growing skeleton (Figs. 12.6,12.7). 

This is the most severe type and results in total sacroiliac joint disruption. Features of the Type 1 and 2 pattern may be present. There is widening of the sacroiliac joint and there is diastasis both posteriorly as well as anteriorly due to the posterior sacroiliac ligament rupture. On clinical examination, the hemi-pelvis is unstable in all directions of force and typically requires operative stabilisation. It is possible for the sacroiliac joint to remain intact but there is fracture of the sacroiliac bone. Complications include bladder rupture, and vascular injury (Figs. 12.8,12.9). 

This is the least severe type of injury pattern with internal rotation of the innominate bone which pivots on the anterior margin of the sacroiliac joint. There may be compression fractures of the sacrum. Pubic rami fractures are common and typically have a known oblique orientation but can be comminuted, compared with the vertical fractures of AP compression injuries (Figs. 12.10,12.11). 

This is usually the result of forces transmitted through the axial skeleton from an impact into the head and shoulders through to the lower limbs. There may be symphyseal diastasis, anterior arch fractures or posterior disruption of the sacroiliac joints with cephalic displacement. Vertical injuries are often severe with disruption of all the ligaments plus associated pelvic instability. Radiographs demonstrate ipsilateral or contralateral pubic rami fractures, with disruption of the sacroiliac joint. The major differentiating feature from compression injuries is the cephalic displacement of the pelvis on the side of the impact (Fig. 12.14). 

These relate to fractures or disruption of the pubic symphysis and are associated with anterior sacroiliac joint disruption. The posterior iliac ligament complex is unaffected and pelvic stability is maintained. In the older child, widening of the pubic symphysis beyond 2.5 cm is associated with disrup-... 

B2.2 partial sacroiliac joint fracture plete rupture of posterior arch)... 

Harris JH Jr, Lee JS, et al. (2004) Acetabular fractures revisited part 1, redefinition of the Letournel anterior column. AJR Am J Roentgenol 182 1363-1366 Heeg M, Visser JD, et al. (1988) Injuries of the acetabular triradiate cartilage and sacroiliac joint. J Bone Joint Surg Br 70 34-37... 

We administer 800-1000 mL of oral contrast (dilute Gastrograffin) in small increments over 1.5 h before the examination is to be performed. The patient is then placed on the CT table and a scout topogram is obtained to document filling of the cecum. If it is uncertain whether there is filling of the cecum, a single CT slice at the level of the sacroiliac joints can be obtained. If the cecum is opacified, we begin the examination, otherwise, the patient is taken off the CT scanner and waits an additional 30 min and then placed back on the CT scanner. 

Fig. 35.4. a T1-weighted image postcontrast with fat saturation shows bilateral diffuse enhancement within the sacral wings. Since the patient preciously had a carcinoma of the uterus and because of increased uptake in the bone scan, bony metastases were suspected, b CT shows serpiginous sclerosis within the sacrum parallel to the sacroiliac joint typical for sacral insufficiency fractures. The patient had previously received radiation therapy of the pelvis, which is known to result in local osteoporosis with weakening of the bone. The patient was followed-up, and bisphosphonates were administered... 

II Single breaks in the ring near the pubic symphysis or a sacroiliac joint... 

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