A 16-year-old male was sent to the orthopaedic clinic the day after having sudden onset of pain in his left groin. He was doing drills during his soccer practice after warming up and had a sudden pain when attempting to strike the ball. He did not hear any sounds, but had instant pain and fell to the ground. He had difficulty flexing his hip and was helped to the sidelines. The coach immediately applied ice, he rested over the evening and the family had crutches at home that he was using for mobility.
The pertinent physical exam showed the patient had normal vital signs and growth parameters. His general physical examination was normal. His was holding his left leg slightly extended. There was swelling and a small mass palpable on the anterior inferior iliac spine on the left side. Attempts at flexion of the hip induced pain.
The radiologic evaluation included a plain radiograph which showed the diagnosis of a non-displaced avulsion fracture of the anterior inferior iliac spine consistent with his physical examination and history.
The patient’s clinical course had the patient put on non-weight bearing and rest for 6 weeks. At 6 weeks he started doing toe touching and walking on flat ground. Radiographs at 8 weeks showed union of the fracture and his physical examination showed hip stability without pain. Although he had some deconditioning, he was cleared for increasing his sports participation.
Avulsion fractures of the pelvis are more commonly seen in adults and teenage athletes. Currently they are more common in male athletes but with the increased number of females in sports, more are also being seen in females. Soccer and track and field are common sports where these injuries occur. The injuries are felt to be caused by a repetitive traction on the apophysis or more commonly due to a ‘sudden, forceful, or unbalanced contraction of an attached musculotendinous unit while engaged in a sporting event…. Skeletal maturity has a direct effect on the incidence of the injury.” They can occur more often around the time of ossification and therefore there may be slight differences of age. For example, the anterior inferior iliac spine (AIIS) fuses at 16-18 years and the anterior superior iliac spine (ASIS) fuses at 21-25 years. The lesser trochanter fuses at 15-17 years and the ischial tuberosity at 20-25 years. A recent review found ~2/3 of patients with AIIS and ~1/3 with ASIS fractures, with the average ages of pelvic avulsion fractures being 14.4 years in males and 13.7 years in females.
The patient usually moves in a way that causes sudden muscle contraction (i.e. kicking the ball, sprinting) and then has instant pain at the fracture site and loses function of the muscle. A lump may be noted which is the avulsed fragment of bone. There can be swelling and tenderness in the affected area, along with reproducible pain with movement of the appropriate muscle group. Plain radiographs usually will show the avulsion injuries however sometimes radiographic appearances can look destructive, lytic or sclerotic which may be confused with malignancies or osteomyelitis. Magnetic resonance imaging may be needed in some cases. Avulsion injuries are usually unilateral but can be bilateral and they have been recorded to occur in all muscle attachments.
Treatment for avulsions injuries of the pelvis usually is rest with analgesics. Crutches for non-weight bearing initially are helpful. Over time gradual mobilization from toe touching to full weight bearing is done. Eventually running and sport specific training is resumed. Many patients can oversee this themselves but others may need the help of a physical therapist to help with flexibility and muscle strengthening. Surgical pinning of the fragment is sometimes needed (in the review article only 6% had surgery) if the fragment is large (>2 cm) or displaced. Other reasons include conservative treatment failure, non-union of the fracture, or exostosis formation, or impingement for example. Usually there is very good to excellent outcomes of these fractures with conservative management of these patients with healing around 8 weeks after injury and most patients are back to sports by around 3 months.
Questions for Further Discussion
1. What are indications for orthopaedic traction?
2. What are indication for a spica cast?
3. Describe Salter-Harris fracture classification. A review can be found here.
- Disease: Iliac Spine Fractures | Hip Injuries and Disorders
- Symptom/Presentation: Pain
- Specialty: Orthopaedic Surgery and Sports Medicine
- Age: Teenager
To Learn More
To view pediatric review articles on this topic from the past year check PubMed.
Information prescriptions for patients can be found at MedlinePlus for this topic: Hip Injuries and Disorders
To view current news articles on this topic check Google News.
To view images related to this topic check Google Images.
To view videos related to this topic check YouTube Videos.
Naylor JA, Goffar SL, Chugg J. Avulsion fracture of the anterior superior iliac spine. J Orthop Sports Phys Ther. 2013;43(3):195. doi:10.2519/jospt.2013.0406
Ali E, Khanduja V. Adolescent avulsion injuries of the pelvis: a case study and review of the literature. Orthop Nurs. 2015;34(1):21-26, quiz 27-28. doi:10.1097/NOR.0000000000000115
Yin H, Huang Z, Pan Z. Simultaneous bilateral avulsion fracture of the anterior-superior iliac spine in a teenager: a case report with a literature review. J Pediatr Orthop B. 2018;27(5):404-406. doi:10.1097/BPB.0000000000000391
Anduaga I, Seijas R, Perez-Bellmunt A, Casasayas O, Alvarez P. Anterior Iliac Spine Avulsion Fracture Treatment Options in Young Athletes. J Invest Surg. 2020;33(2):159-163. doi:10.1080/08941939.2018.1483447
Donna M. D’Alessandro, MD
Professor of Pediatrics, University of Iowa