In pelvic injuries, the injury mechanism and the strength of the energy causing the injury are determining factors. In young people, pelvic fractures are associated with high-energy blunt trauma, in the elderly most often with low-energy falls (osteoporosis).
High-energy fractures are often associated with severe injuries. The most severe associated injury is life-threatening haemorrhage. Other possible associated injuries include injuries to the lumbar plexus, bladder and urethra, and various degrees of soft tissue injury.
All pelvic fractures require pelvic CT and therefore treatment assessment at a hospital.
Diagnosis
A pelvic fracture should always be suspected in the event of high-energy blunt trauma (such as a traffic accident or falling from a height > 1.5 m).
Malrotation of the pelvis or lower limbs and a difference in the length of the lower limbs in the absence of fractures of long bones strongly suggest a dislocated pelvic ring fracture.
A shortened limb and inward malrotation in association with acetabular fracture suggest posterior luxation of the hip joint.
The diagnosis of a fracture is based on imaging.
Sensory and motor functions of the lower limbs should be examined.
Classification
Fractures of the pelvic ring are classified into three main types based on pelvic stability.
Type A: the pelvic ring is stable (e.g. fracture of the iliac crest).
Type B: the pelvic ring is unstable either on external or internal rotation.
Type C: the pelvis is also vertically unstable.
Injuries to the lumbar plexus are most often associated with type C fractures (prevalence about 40-50%).
Acetabular fractures are due to an impact to the femoral head. The type of fracture depends on the strength and direction of the force and on its distribution in the area of the acetabulum.
Nerve injuries are most commonly associated with posterior dislocation of the hip (peroneal paresis).
High-energy injuries to the pelvic ring
The patient should be examined and treatment provided in specialized care.
It is important to recognize the possibility of bleeding, neurological damage and associated urological injuries.
If the patient is haemodynamically unstable, shock should be treated and bleeding controlled rapidly and effectively, and the unstable pelvic ring should be temporarily supported.
The treatment should follow the cABCDE principle, where tamponade of major external bleeding is the first priority (c = control of catastrophic bleeding).
The pelvic girdle should be supported with a pelvic belt to control bleeding.
If critical haemorrhage occurs, embolization, pelvic packing and/or an occlusion balloon placed in the descending aorta can be used.
Treatment is mainly operative. The aim of the treatment is to restore the anatomy of the pelvic ring and to fix it so as to facilitate early mobilization.
Low-energy injuries to the pelvic ring
A compression-type ramus fracture of the anterior pelvic ring is a typical injury.
A fall may lead to a sacral fracture, most often of the compression-type, with no vertical instability.
A rare transverse sacral S1-S2-level fracture may be associated with cauda equina syndrome (progressive sensory disorder at perineal S1-S2 area, motor weakness of a lower limb and difficulty starting urination).
Imaging may be begun with anteroposterior x-ray of the pelvis, but CT is usually needed to define the severity of the fracture and to decide on the line of treatment.
If a transverse sacral fracture is suspected, a lateral x-ray of the sacral bone should be taken.
A patient with a non-displaced, stable fracture of the pubic ramus needs no bed rest. Mobility and weight bearing should be allowed within the limits of pain.
Sacral fractures
A sacral fracture may be vertical (longitudinal), transverse (horizontal) or bilateral, in which case the spine may be detached from the pelvic ring.
Nerve damage may occur, particularly in association with dislocated fractures.
Vertical (longitudinal) fractures
Vertical type C sacral fractures can be classified according to whether the fracture runs laterally from the sacral nerve root openings (foramina sacralia), through the openings or medially from them.
The more medial the fracture, the more likely the development of associated neurological injuries.
Vertical fractures are usually treated surgically.
Transverse (horizontal fractures)
Isolated transverse sacral fractures are rare, accounting for 3-5% of all sacral fractures only.
The mechanism of injury is usually a fall onto the buttocks.
Transverse sacral fractures situated below the SI joint level will not affect the stability of the pelvic ring and can be treated conservatively.
If the fracture is situated at the S1-S2 level, cauda equina syndrome (progressive sensory disturbance in the S1-S2 region, motor weakness of a lower limb and difficulty starting urination) may develop.
Spinopelvic dissociation
In this rare type of fracture, there are bilateral vertical fracture lines in the sacral bone, combined with a transverse fracture leading to the detachment of the spine from the pelvic ring.
High-energy sacral fractures associated with spinopelvic dissociation are treated surgically.
Low-energy fractures of the pelvic ring in the elderly
The prevalence of pelvic fractures caused by low energy or in the absence of any clear accident (fragility fracture) is increasing among the elderly. Pain in the pelvic or sacral area may suggest a fracture of the pelvic ring.
The diagnosis is based on imaging.
Depending on regional guidelines, either CT or anteroposterior pelvic x-ray and a lateral image of the sacral bone as necessary
For patients confined to bed, x-raying is often sufficient.
Urgent assessment of need for surgery is necessary in patients with cauda equina syndrome.
Conservative multiprofessional treatment is the primary option. Treatment aims at alleviating pain, early mobilization and restoring functional capacity.
If a previously mobile patient cannot be rehabilitated to restore their walking ability within a few weeks, surgery should be considered.
Acetabular fractures
The treatment principles do not differ from those of any other fracture of weight-bearing joint surfaces.
Well-aligned fractures with no significant dislocation in the area of a weight-bearing acetabular joint surface can be treated conservatively (reduced weight-bearing).
Regardless of the patient's age, surgical treatment aims at anatomical reduction, stable fixation and early mobilization.
Osteoporosis, a comminuted fracture and difficulty reducing weight-bearing complicate the treatment of injuries in the older age group.
Some such fractures can be treated by arthroplasty.
Coccygeal fractures
A coccygeal fracture is typically a transverse fracture distally in the area of the coccygeal apex.
The diagnosis is based on clinical findings. It can be confirmed by lateral x-ray of the sacral bone.
Treatment is conservative: a pressure relief seat cushion for sitting should be used.
References
Salminen P, Pajarinen J, Tolonen M, Äärimaa V (eds.). [Handbook of emergency surgery]. 4th revised edition. Duodecim Publishing Company 2024. Available in Finnish.
Gänsslen A, Lindahl J, Grechenig S, Füchtmeier B, eds. Pelvic ring fractures. Cham: Springer Nature Schwitzerland AG; 2021. ISBN 978-3-030-54729-5. eBook ISBN 978-3-030-54730-1. DOI: 10.1007/978-3-030-54730-1.
Lindahl J, Hirvensalo E. [Pelvic fractures]. In: Kröger H, Aro H, Böstman O, Lassus J, Salo J. [Traumatology]. 8th revised edition. Kandidaattikustannus Oy 2019;39:499-520. Available in Finnish.
Gänsslen A, Müller M, Nerlich M, Lindahl J, eds. Acetabular fractures - Diagnosis, indications, treatment strategies. Stuttgart: Georg Thieme Verlag KG; 2018. ISBN-13: 978-3-13-241560-7.