Sacroiliac joint inflamation - Sacroiliitis
Anatomical location of the sacro-iliac joints

Definition

Sacroiliitis refers to the inflammation of the sacro-iliac joint, which connects the iliac bone on each side of the pelvis to the sacral spine.

Area of the pelvis where the pathology sacroiliitis occurs

Pathology

Sacroiliitis is an inflammatory condition of the sacro-iliac joint that can arise after a traumatic event, infection or overuse. Chronic sacroiliitis causes fibrosis and calcification of the joint and in the long-term stiffness (ankylosis). 

This pathology is distinguished from sacroiliac joint dysfunction, which presents similar symptoms but is the consequence of abnormal motion at the sacro-iliac joint, which over time becomes inflamed. Occasionally, it occurs in the context of other diseases such as ankylosing spondylitis or Reiter’s syndrome. In patients with systemic chronic autoimmune spondylo-arthropathy of the spine, ongoing inflammation leads to bone loss and ossification of soft tissue also involving the sacro-iliac joint. Sacroiliitis is frequent in adolescent to middle aged individuals and is more common in men than women but can arise during pregnancy.

Colles' fracture with bone displacement seen before (left) and after closed reduction (right) in a cast

Classification

The fractures of the distal radius are defined with various classification systems including the AO (Arbeitsgemeinschaft fuer Osteosynthese) system. They relate to the mechanisms of injury and bone fracture characteristics and provide a guideline towards suitable treatments. The most frequent types of distal radius fracture are:

No 1.

Colles’ fracture is the most common type of fracture in which the distal bone of the radius tilts upwards following an outer bending of the wrist as it happens when falling on the hand

Smith’s fracture or reversed Colles’ fracture occurs when the distal portion of the radius tilts downwards following the inward bending of the wrist

Barton fracture is an intra-articular fracture of the distal radius with dislocation of the radiocarpal joint

Chauffeur fracture is an intra-articular fracture of the radial styloid process, also known as Hutchinson fracture or backfire fracture.

Left: Distal radius intraarticular, displaced fracture; Middle: Older distal radius fracture with callus formation; Right: Distal radius and ulna fracture, extraarticular and displaced

No 2.

Intra-articular fracture extends to the wrist joint (or articulation)

Extra-articular fracture is located outside of the wrist joint

Open fracture when bone fragments perforate the skin

Comminuted fracture when the bone breaks into multiple fragments

Non-displaced when the anatomical alignment of the bone is maintained or displaced when the bone fragments move apart.

Melone’s classification describes the characteristics of intra-articular fractures of the radius:

i    Stable fracture

ii    Unstable "die-punch"

iii   "Spike" fracture

iv Split fracture

v   Explosion injuries

Acetabular fracture of the pelvis

Acetabular fractures

These fractures are divided into:

Anterior pillar (not weight bearing part of joint)

Posterior pillar (often associated with dislocation of the hip including the weight bearing part of joint)

Transverse

Comminuted involving both column type 

Sacral / coccygeal fractures

The sacrum is a triangular-shaped bone formed by 5 fused vertebrae, which provide a posterior wall to the pelvic ring. At each side of the sacrum, the ala structures articulate with the ilium bones forming the sacro-iliac joints. Sacral fractures are usually parallel to the spine and can involve the ala. Less frequently sacral fractures may display an “H” shape, including a transversal fracture uniting both sides of the sacrum. Three zones are described where sacral fractures can occur that are along vertical lines relative to the alignment of the foramina. Sacral fractures may result in sacral instability and require treatment via sacroplasty (injection of bone glue into the fracture). Surgery is necessary in case of associated neurological symptoms.

Fractures of the coccyx involve the tailbone, the terminal portion of the spine situated below the sacrum formed by 3 to 5 fused vertebrae. Coccyx fractures occur when falling on a seated position. They are more common in elderly women and seldom require surgical treatment.

Difference il leg length can lead to sacroiliitis

Causes

There are various causes leading to sacroiliitis but in some cases the origin of the disease is unknown. These are:

Trauma (e.g. car accident with strong impact while pressing the break pedal)

Fall

Prolonged sacro-iliac joint dysfunction

Infection (bacteria migrating and depositing in the sacro-iliac joint)

Leg length discrepancy

Chronic arthritic conditions (rheumatoid/psoriatic arthritis, Reiter’s syndrome, autoimmune spondylo-arthropathy)

Pregnancy

Bilateral sacro-iliac arthritis in predisposed individuals can manifest into sacroiliitis

Risk factors

Leading risk factors for a sacroiliitis include:

Frequent driving

Working at height (carpenters, electricians, builders, painters)

Aged between teen years and middle age

Male gender

Chronic autoimmune diseases

Specific genetic group predisposed to arthritis

Pregnancy

The glutei muscles of the buttocks are subject to symptomatic consequences to sacroiliitis

Symptoms

The most frequent symptoms of sacroiliitis include:

Pain to the low back radiating to the buttocks, front thigh and hip (unilateral or bilateral)

Pain increasing after prolonged standing and siting or when rolling over in bed, walking stairs

Stiffness of the hips and low back in the morning wake

Weakness of hip muscles

Muscle spasms buttocks

Difficulty in walking with long steps

Fever

External rotation of the hip is one of the procedures used for the diagnosis of sacroiliitis

Diagnosis

Clinical examination begins with medical history to review potential preexisting diseases and past injuries that may contribute to sacroiliitis . The Faber test is employed to monitor functional changes and pain level during hip flexion, abduction and external rotation. In addition, the examiner will assess the presence of spinal deformities especially in the thoracic and lumbar tracts.

X-ray imaging is not considered to be specific but may indicate degenerative changes of the bones forming the sacro-iliac joint and spine. Improved imaging is obtained with MRI using contrast agent (gadolinium) to visualise the accumulation of fluid and ongoing inflammatory processes (abscess).

Other laboratory tests include:

White blood cell count

C-reactive protein levels in blood (inflammation parameter)

Blood cultures if bacterial infection is suspected

Genetic testing for predisposition to autoimmune arthritis (HLA-B27)

Treatment

Electrical stimulation

Nonoperative treatment

When an infection is confirmed the patient is treated initially with intravenous antibiotics followed by oral antibiotics. If sacroiliitis manifests in association with spondylopathy, the patient is given a strong antiinflammatory therapy, local injection of steroids, oral NSADs or other specific drugs such as TNF inhibitors. Other topical therapy includes muscle relaxants and anaesthetics. Improvement of joint lubrication and pain is achieved with local injection of hyaluronic acid.

In pregnancy this condition is usually transitory and improves after birth. If pain does not resolve the sensory nerves around the sacro-iliac joint are destroyed using a special technique named radiofrequency ablation or with the implantation of an electrical stimulator in the sacrum. This method however may only provide transitory benefit and require additional treatments 1-2 years later.

Two examples of sacro-iliac fusion although performed after a pelvic fracture and not in sacroiliitis

Surgical treatment

Surgery is only indicated in case of trauma, severe infection with large abscess formation and significant degenerative changes of the sacro-iliac joint. When conservative treatment does not improve and pain is sustained, a joint fusion may be the only option. The surgery consists firstly in the removal of the cartilage on either side of the bones forming the joint followed by the fusion of the sacrum and iliac bones with plates and screws. By blocking completely the movement at the sacro-iliac joint the pain should resolve but may persist in some cases.

Bridge pose is useful to strengthen the buttocks muscles and protect the sacro-iliac joints

Rehabilitation

In patients with reduced mobility of the sacro-iliac joint, physiotherapy focuses on restoring flexibility with gentle exercise to improve strength of the trunk, buttocks and thighs and abdominal muscles.

In case of excessive mobility the therapist will recommend the use of a belt to help stabilising the sacro-iliac joint. Following surgery a period of 6 weeks of rest is necessary prior to commence a rehabilitation program.

Physiotherapy treatment includes:

Rest

Ice/heat treatment

Manipulation

Joint mobilisation

Massage

Stretching

Antiinflammatory therapy (NSAIDs)

Activity modifying regime

In case of leg length discrepancy the use of shoe orthotics helps realign the pelvis and spine to prevent sacroiliitis

Prevention

The incidence of sacroiliitis can be prevented by following the rules below:

Maintenance of muscular strength of the lower back, core pelvic muscles and buttocks

Improve flexibility to the lower spine

Ergonomic advice during physical activity, sitting and sleeping

Use of lumbar support with prolonged sitting

Wearing of orthotics to reduce leg length discrepancy or incorrect walking

Modify daily habits to prevent falls (laced shoes, illuminate house at night, install railings, non-skid tiles in bathroom)

Adherence to occupational health and safety procedures and use of road traffic safety equipment (seatbelt, harness, balustrades)

Pharmacological treatment and monitoring of predisposing chronic conditions (arthritis group)