Avulsion of the Ischial Tuberosity

August 1, 2008

A 13-year-old girl felt a “pop” while doing a split during gymnastics. She later complained of right hip pain and inability to bear weight on the right leg.

Lisfranc Ligamental Injury

Salter-Harris II Fracture of the Distal Phalanx

Avulsion of the Ischial Tuberosity



A 13-year-old girl felt a “pop” while doing a split during gymnastics. She later complained of right hip pain and inability to bear weight on the right leg.

Limited range of motion was noted during flexion and internal rotation of the right hip. The patient had pain on palpation over the right ischium and was unable to fully extend her right knee. There was no radiation of pain down the leg and no local bruising or swelling. Anteroposterior (A) and frog-leg (B) radiographs of the pelvis revealed a nondisplaced avulsion fracture of

the right ischial tuberosity.

Avulsion of the ischial tuberosity can occur in children and adolescents because the ischial growth plate remains open until age 25 years.1 During sudden straight-leg raising with the knee extended and hip flexed, the hamstring lengthens and pulls the ischial growth plate. Avulsion can result from sudden contraction of the hamstrings during forceful physical activity, such as sprinting, hurdling, and gymnastic exercises (eg, splits). It may also result from chronic repetitive traction without an acute episode.

Avulsion of the ischial tuberosity is often mistaken for hamstring injury, which delays recovery.2 Misdiagnosis is more likely if the patient is not examined specifically for tenderness or a gap at the ischial hamstring origin.

The radiograph of the acute lesion shows a crescentshaped shadow below or lateral to the ischial physis with varying degrees of separation. In the subacute phase, there is destruction at the fracture site and callus formation that causes a mixed lytic and sclerotic lesion that may mimic an aggressive bone-forming neoplasm (pseudotumor of the ischium), such as Ewing sarcoma, lymphoma, or osteosarcoma.1

Nondisplaced avulsion can be treated conservatively with rest, rehabilitation, and avoidance of hamstring stretching. The amount of displacement is important in deciding the type of treatment of displaced avulsion. Conservative treatment may be adequate in avulsions with less than 2 cm of displacement.3 Avulsions with greater than 2 cm of displacement require reduction and fixing of the avulsed fracture immediately to prevent mobile nonunion with substantial pain and weakness of knee flexion.4

All patients need orthopedic follow-up for conservative or operative treatment as well as for their return to active sports. Most fractures heal without complications.

References:

REFERENCES:


1.

Bahk WJ, Brien EW, Luck JV Jr, Mirra JM. Avulsion of the ischial tuberositysimulating neoplasm-a report of 2 cases.

Acta Orthop Scand.

2000;71:211-214.

2.

Gidwani S, Jagiello J, Bircher M. Avulsion fracture of the ischial tuberosity inadolescents-an easily missed diagnosis.

BMJ.

2004;329:99-100.

3.

Bedrettin A, Ertan O. Avulsion of the ischial tuberosity in a young soccer player:six years follow-up.

J Sports Sci Med.

2002;1:27-30.

http://www.jssm.org/vol1/n1/3/v1-3pdf.pdf

. Accessed June 11, 2008.

4.

Wootton JR, Cross MJ, Holt KW. Avulsion of the ischial apophysis. The casefor open reduction and internal fixation.

J Bone Joint Surg Br.

1990;72:625-627.