Small percentage of patients who require surgery also have good outcomes

Jennie McKee

About 95 percent of adolescents with apophyseal avulsion fractures of the hip and pelvis may be successfully treated with conservative treatment, according to data from a retrospective study involving more than 400 such cases. The study was presented at the 2014 American Orthopaedic Society for Sports Medicine (AOSSM) Specialty Day.

“Apophyseal avulsion fractures of the hip and pelvis occur almost exclusively in the adolescent population, usually secondary to a sudden, eccentric contracture of the attached muscle or tendon units during sports,” stated presenter Benton E. Heyworth, MD, of Boston Children’s Hospital (BCH), whose fellow researchers included senior author Lyle J. Micheli, MD, director of the BCH Division of Sports Medicine.

“We’re seeing greater numbers of these injuries due to the increased participation in youth sports, a higher level of competition, and more intense training. We are also seeing more overuse injuries involving apophysitis, a common precursor to avulsion fractures,” said Dr. Heyworth.

Despite the growing incidence of apophyseal avulsion fractures in young athletes, little data exist related to these injuries. This led Dr. Heyworth and his fellow researchers to focus on treatment indications, clinical course, and outcomes of treating apophyseal fractures.

“We hypothesized there would be a low rate of fractures requiring surgical treatment and high rates of return to play,” he noted.

Collecting and assessing the data
Investigators used a department database query to identify all cases of apophyseal avulsion fractures treated between 1993 and 2012 at a single tertiary care pediatric hospital. Researchers reviewed orthopaedic clinic notes, sports medicine clinic notes, and surgical reports. They also performed a radiologic review of all surgical cases, as well as select nonsurgical cases.

The nonsurgical cohort included 413 patients (72 percent male; mean age: 14.5 years). The surgical cohort included 22 patients (77 percent male; mean age: 15.7 years). Researchers identified the anatomic sites of injury, sports played at time of injury, treatment approaches used, and patient outcomes.

In the nonsurgical cohort, the three most common sites of anatomic injury were the following:

• Anterior inferior iliac spine: 29 percent (120 patients)
• Anterior superior iliac spine: 27 percent (111 patients)
• Ischial tuberosity: 17 percent (70 patients)

“The sports played at the time of injury support the notion of the eccentric contraction etiology,” said Dr. Heyworth. Three sports—soccer (26 percent), track and field/running sports (13 percent), and baseball/softball (11 percent)—accounted for more than half of the injuries incurred, far surpassing the number of apophyseal avulsion fractures sustained in contact sports, such as football and ice hockey.

According to Dr. Heyworth, nonsurgical patients underwent “a standard array of nonsurgical modalities, including early activity restriction for all patients.” More than half of nonsurgical patients required crutches, while two thirds underwent physical therapy.

“Mean time of union or healing was 2.7 months, and return to sports occurred soon after, at a mean time of 2.8 months,” said Dr. Heyworth.

In the surgical cohort (22 patients), the three most common sites of anatomic injury were as follows:

• Ischial tuberosity: 64 percent (14 patients)
• Anterior inferior iliac spine: 18 percent (4 patients)
• Iliac crest: 14 percent (3 patients)

The two most common sports played at time of injury in this patient cohort were soccer (18 percent) and track and field/running (18 percent), followed by baseball/softball (9 percent).

When addressing the data related to the surgical cohort, Dr. Heyworth noted that “prolonged nonsurgical treatment had been unsuccessful in two thirds of patients in the surgical cohort, while approximately one third of these patients had acute fractures.”

Among patients with fractures of the ischial tuberosity, half underwent open reduction and internal fixation (ORIF), with a mean time to union of 4.8 months. The remainder of the cohort underwent either apophyseal fragment excision (21 percent) or apophyseal fragment excision and hamstring repair (29 percent).

For fractures of the anterior inferior iliac spine, other surgical techniques included open (2 patients) or arthroscopic (1 patient) osteoplasty to whittle down the bone and repair the labrum. One patient with a fracture of the iliac crest was treated with excision of the fragment and external oblique repair, while two others underwent drilling of the nonunion site. Dr. Heyworth noted that one additional patient with a fracture of the anterior superior iliac spine underwent apophyseal fragment excision.

Drawing conclusions
“In more than 400 cases of apophyseal avulsion fractures, at least 95 percent were effectively treated nonsurgically, with a mean time of healing and return to sports at 2.5 to 3 months,” said Dr. Heyworth, noting that only about 5 percent of patients required surgical intervention. In surgical patients, the ischial tuberosity was the most common anatomic location of fracture.

“Most patients who required surgery had initial conservative care that was unsuccessful. These patients subsequently underwent fragment excision, rather than fixation, due to the chronic nature of their injury,” stated Dr. Heyworth.

Dr. Heyworth called for prospective studies to better determine indications for surgery in patients with apophyseal avulsion fractures.

“Better understanding of the rare indications for early fixation as well as the most effective functional outcomes measures for these injuries is warranted,” he noted, “given the increasing frequency of overuse injuries and youth sports injuries.”

Dr. Heyworth’s coauthors of “Results of Non-operative and Operative Management of Apophyseal Avulsion Fractures of the Hip and Pelvis in Adolescent Athletes,” are Bryant Bonner; Catherine A. Suppan, BA; Mininder S. Kocher, MD, MPH; Yi-Meng Yen, MD; and Lyle J. Micheli, MD.

Disclosures: Dr. Heyworth—Trauma Committee, Pediatric Orthopaedic Society of North America (POSNA); Research in Osteochondritis Dissecans of the Knee Study Group; Mr. Bonner and Ms. Suppan—no conflicts; Dr. Kocher—Biomet, Best Doctors, Gerson Lehrman Group, OrthoPediatrics, Smith & Nephew, Fixes 4 Kids, Pivot Medical, Saunders/Mosby-Elsevier, ACL Study Group, AOSSM, Harvard Medical School, Harvard School of Public Health, Herodicus Society, POSNA, PRISM; Dr. Yen—Agios Pharmaceuticals, Smith & Nephew, Orthopediatrics, Arthrex, Inc; Dr. Micheli—Carticel, Genzyme, International Federation of Sports Medicine.

Jennie McKee is a senior science writer for AAOS Now. She can be reached at mckee@aaos.org

Bottom Line

• This retrospective study involving more than 400 adolescent athletes with apophyseal avulsion fractures of the hip and pelvis found that 95 percent of patients treated at one tertiary care pediatric center from 1993 to 2012 received conservative treatment and successfully returned to play in approximately 2.5 to 3 months.
• The most common anatomic sites of injury in nonsurgical patients were the anterior inferior iliac spine (29 percent), anterior superior iliac spine (27 percent), and ischial tuberosity (17 percent).
• By far, the ischial tuberosity (64 percent) was the most common site of anatomic injury in surgical patients.
• Nonsurgical patients returned to play in 2.5 to 3 months, while patients in the surgical group—such as those with fractures of the ischial tuberosity who underwent ORIF—had a mean time to union of 4.8 months.
• According to Dr. Heyworth, prospective studies are needed to learn more about the rare indications for early fixation of apophyseal avulsion fractures, as well as about the most effective outcomes measures for these injuries.