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Ischial Tuberosity Avulsion Fracture

From WikiSM

Other Names

  • Ischial Tuberosity Avulsion Fracture
  • Ischial Apophysis Avulsion Fracture
  • Apophyseal Avulsion Fracture of Ischial Tuberosity
  • Avulsion Fracture of ischial tuberosity (AFIT)

Background

History

  • First case report by Berry in 1912[1]

Epidemiology

  • Among hamstring injuries, avulsion fractures estimated to by present 1.4% to 4% of the time[2]

Demographics

  • Most commonly occurs in adolescents age 15 to 19 years[3]
  • Average age of pelvic avulsion fractures is 13.8 (Rossi et al[4]), 16.8 (Porr et al[5])

Introduction

Bony anatomy of the ischium[6]
Left ischial apophysis avulsion injury (red arrow). [7]

General

  • Rare injury seen in athletes who sustain hamstring injuries
  • Most commonly occurs with forceful hip flexion, knee extended and eccentric load to hamstrings
  • Management is somewhat controversial and depends on degree of displacement

Etiology

  • Sudden forceful hip flexion, knee extended with eccentric load to hamstrings
  • Eccentric hamstring loads generate more force, tension at the hamstrings insertions
  • Activities thought to predispose to injury
    • Repetitive kick motions
    • Running sprints
  • Hamstring injuries tend to occur during the latter part of the swing phase[8]
    • In this phase, they are working to decelerate knee extension, prepare for heel strike

Anatomy of the Ischial Tuberosity

  • Posteriorinferior aspect of the ischium
  • Muscle attachments: semitendinosus, semimembranosus, long head of biceps femoris
  • These tuberosities bear our weight when sitting or falling
  • Apophysis tends to fuse by age 25, later than many other epiphyseal centers[9]

Risk Factors

Sports

Other

  • Ischial Tuberculosis

Differential Diagnosis

Differential Diagnosis Avulsion Fracture of Ischial Tuberosity

Differential Diagnosis Hip Pain

Clinical Features

History

  • Sudden pain in the back of thigh or hip
  • Abnormal gait or even inability to walk
  • Patients often describe or feel a pop

Physical Exam: Physical Exam Hip

  • Swelling of the buttocks
  • Ecchymosis and tenderness at the ischial tuberosity
  • Inability to sit
  • Trouble with hip/knee flexion/extension

Special Tests

  • Greatest pain is reproduced with hip extension, adduction, external rotation
(A) X-ray of the right hip showing the avulsed ischial tuberosity. Note that the x-ray can detect larger displaced fracture blocks. (B) Typical computed tomography (CT) image of the avulsion fracture of the ischial tuberosity. Note that CT can easily detect small displaced fracture blocks. (C) The 3D-CT clearly depicts the shell-like fragment of the displaced fracture block. Note that the 3D-CT scan can more intuitively show the avulsion fractures. (D) Typical coronal magnetic resonance imaging (MRI) scan of the pelvis/thigh demonstrating the displaced ischial tuberosity. Note that MRI can detect occult fractures through the edema-like signal intensity and subperiosteal fluid volume of the sciatic nerve nodules and surrounding soft tissues[11]

Evaluation

Radiographs

Computed Tomography (CT)

  • More sensitive for subtle fractures with minor displacement, partial avulsion

MRI

  • Required when lesion is occult[12]
  • Findings
    • Edema-like signal intensity of the ischial tuberosity
    • Surrounding soft tissue swelling
    • Subperiosteal fluid

Ultrasound

  • Role is not well defined
  • May be able to detect whether nerve damage is present
  • General agreement is MRI is superior[13]

Classification

  • No classification currently exists
Proposed treatment algorithm.[11]

Management

Nonoperative

  • Indications
    • Consider in athletes with displacement < 2 cm
    • Sometimes called small degree of fracture displacement
  • Objectives
    • Rest
    • Achieve pain control
  • Non-weight bearing
  • Limited physical activity
  • Physical Therapy
  • Close follow up and serial radiographs to confirm no further displacement
    • If fracture doesn't heal or pain persists, then consider surgery

Operative

  • Indications
    • Somewhat controversial
    • Bone displacement > 2 cm
    • Physically active patients with displacement > 1.5 cm[14]
  • Technique
    • Open reduction, internal fixation

Rehab and Return to Play

4 Stage Nonoperative Rehabilitation Program[15]

  • Phase 1 (0-3 weeks)
    • Inability score index (ISI) 590
    • RICE (rest, ice, compression and elevation), nonsteroid anti-inflammatory therapy
    • 1 week of careful passive mobilization with soft stretching
  • Phase 2 (3–8 weeks)
    • When 50≤ ISI <90
    • Progressive agility and trunk stabilization exercises
    • Low to moderate intensity
  • Phase 3 (8–16 weeks)
    • When 10≤ ISI <50
    • Progressive agility and trunk stabilization exercises
    • High intensity (velocity of movement similar to sport activity)
  • Phase 4 (16–24 weeks)
    • When ISI was <10
    • Initially focused on static stretching and isometric strengthening
    • Subsequently on dynamic stretching with concentric and eccentric hamstring strengthening

Postoperative Rehabilitation Plan

  • Similar to conservative plan
  • However since fracture is now reduced, can start weight bearing and functional exercises earlier

Return to Play

  • Needs to be updated

Prognosis and Complications

Prognosis

  • Non-operative
    • 6 year follow up case report shows good outcome after conservative treatment for less than 2 cm displacement[16]
  • Surgical
    • ORIF in chronic cases with disability can relieve symptoms, restore function[17]
    • Early operative treatment gives better results than later surgery[18]
  • Bodendorfer compared Operative vs Nonoperative management[19]
    • Better outcomes found superior outcome with surgical management
    • Particularly true in athletes demanding excessive activity

Complications

  • Significant disability
  • Prolonged pain
  • Difficulty sitting
  • Muscle weakness
  • Decreased functional activity

See Also

Internal

External

References

  1. ↑ Berry JM. Fracture of the tuberosity of the ischium due to muscular action. JAMA. 1912;lix(4662):1450.
  2. ↑ Cohen S, Bradley J. Acute proximal hamstring rupture. J Am Acad Orthop Surg 2007;15:350-5.
  3. ↑ Kujala UM, Orava S. Ischial apophysis injuries in athletes. Sports Med 1993;16:290-4.
  4. ↑ Rossi F, Dragoni S. Acute avulsion fractures of the pelvis in adolescent competitive athletes: Prevalence, location and sports distribution of 203 cases collected. Skeletal Radiol. 2001;30:127–31.
  5. ↑ Porr J, Lucaciu C, Birkett S. Avulsion fractures of the pelvis – a qualitative systematic review of the literature. J Can Chiropr Assoc. 2011;55:247–55.
  6. ↑ Image courtesy of theskeletalsystem.net
  7. ↑ Case courtesy of Andrew Dixon, Radiopaedia.org, rID: 30012
  8. ↑ Lee MJ, Reid SL, Elliott BC, Lloyd DG. Running biomechanics and lower limb strength associated with prior hamstring injury. Med Sci Sports Exerc 2009;41:1942-51.
  9. ↑ Sundar M, Carty H. Avulsion fractures of the pelvis in children: a report of 32 fractures and their outcome. Skeletal Radiol 1994;23:85-90.
  10. ↑ Moon, Jun-Ki, et al. "Apophyseal avulsion fracture of ischial tuberosity during soccer: a case report and literature review." The Korean Journal of Sports Medicine 35.3 (2017): 202-205.
  11. ↑ 11.0 11.1 Liu, Heng, et al. "Avulsion fractures of the ischial tuberosity: progress of injury, mechanism, clinical manifestations, imaging examination, diagnosis and differential diagnosis and treatment." Medical Science Monitor: International Medical Journal of Experimental and Clinical Research 24 (2018): 9406.
  12. ↑ Meyers AB, Laor T, Zbojniewicz AM, Anton CG. MRI of radiographically occult ischial apophyseal avulsions. Pediatr Radiol. 2012;42:1357–63.
  13. ↑ Koulouris G, Connell D. Evaluation of the hamstring muscle complex following acute injury. Skeletal Radiol. 2003;32:582–89.
  14. ↑ Ferlic PW, Sadoghi P, Singer G, Kraus T, Eberl R. Treatment for ischial tuberosity avulsion fractures in adolescent athletes. Knee Surg Sports Traumatol Arthrosc 2014;22:893-7.
  15. ↑ Ceretti M, Di Renzo S. A new evaluation system for early and successful conservative treatment for acute ischial tuberosity avulsion. Chin J Traumatol. 2013;16:254–56.
  16. ↑ Akova B, Okay E. Avulsion of the ischial tuberosity in a young soccer player: six years follow-up. J Sports Sci Med 2002;1:27-30.
  17. ↑ Wootton JR, Cross MJ, Holt KW. Avulsion of the ischial apophysis: the case for open reduction and internal fixation. J Bone Joint Surg Br 1990;72:625-7.
  18. ↑ Sarimo J, Lempainen L, Mattila K, Orava S. Complete proximal hamstring avulsions: a series of 41 patients with operative treatment. Am J Sports Med 2008;36:1110-5.
  19. ↑ Bodendorfer BM, Curley AJ, Kotler JA, et al. Outcomes after operative and nonoperative treatment of proximal hamstring avulsions: a systematic review and meta-analysis. Am J Sports Med 2017 October 10 [Epub]. https://doi.org/10.1177/0363546517732526.
Created by:
John Kiel on 5 July 2019 08:52:11
Authors:
Last edited:
24 June 2025 00:16:06
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