Overview
Definition:
Pelvic apophyseal avulsions are acute fractures occurring at the apophyses (bony outgrowths where tendons attach) of the pelvis in skeletally immature individuals, often precipitated by forceful muscle contractions during athletic activities.
Epidemiology:
These injuries are relatively common in adolescent athletes participating in sports involving sprinting, jumping, kicking, or rapid changes in direction
They most frequently occur in the iliac crest, anterior superior iliac spine (ASIS), anterior inferior iliac spine (AIIS), and ischial tuberosity
Incidence is higher in males, with peak ages between 14-18 years.
Clinical Significance:
Understanding pelvic apophyseal avulsions is crucial for pediatricians and sports medicine professionals to accurately diagnose and manage these potentially debilitating injuries
Delayed or incorrect diagnosis can lead to prolonged recovery, chronic pain, and functional limitations, impacting a young athlete's ability to return to sport and their overall well-being.
Clinical Presentation
Symptoms:
Sudden onset of sharp, localized pain at the affected apophysis during or immediately after strenuous activity
Pain may worsen with specific movements like hip flexion, extension, or resisted muscle action
A palpable tenderness over the affected area
In some cases, a sensation of popping or tearing may be reported
Limp and difficulty bearing weight are common.
Signs:
Tenderness to palpation over the specific pelvic apophysis (e.g., ASIS, iliac crest, ischial tuberosity)
Pain elicited with passive stretching or active contraction of the involved musculature
Swelling and ecchymosis may be present but are not always prominent
Reduced range of motion in the hip joint due to pain
Gait abnormalities, often antalgic.
Diagnostic Criteria:
Diagnosis is primarily clinical, supported by imaging
The presence of acute onset pain localized to a typical apophyseal region in an adolescent athlete engaged in high-risk activities, with reproducible pain on physical examination, strongly suggests an avulsion fracture
Radiographic confirmation is usually required.
Diagnostic Approach
History Taking:
Detailed history of the inciting event, including the sport, specific activity (e.g., kicking a ball, sprinting), and mechanism of injury
Onset of pain (sudden vs
gradual)
Location and character of pain
Aggravating and alleviating factors
Previous similar injuries
Training regimen and any recent changes.
Physical Examination:
Careful palpation of all pelvic apophyses
Assessment of hip range of motion (passive and active) with attention to pain provocation
Specific muscle testing to identify the involved muscle group (e.g., resisted hip flexion for ASIS, resisted knee flexion for ischial tuberosity)
Assessment of gait
Examination of the lumbar spine and contralateral hip to rule out referred pain or other injuries.
Investigations:
Initial imaging usually includes plain radiographs (AP pelvis, lateral view, and oblique views focusing on the suspected apophysis)
X-rays may show displacement of the avulsed fragment or a widening of the apophyseal line
Ultrasound can be useful in identifying avulsions and differentiating from soft tissue injuries, especially in cases with subtle radiographic findings
MRI is the gold standard for definitive diagnosis, assessing the degree of displacement, associated soft tissue injury (edema, hematoma), and ruling out other intra-articular or intraosseous pathology
CT scan can provide more detailed bony anatomy, particularly for complex fractures.
Differential Diagnosis:
Muscle strains (especially in younger children where apophyses are not yet fused)
Osteochondritis dissecans
Stress fractures
Athletic pubalgia (adductor-related pain)
Iliopsoas bursitis
Snapping hip syndrome
Slipped capital femoral epiphysis (SCFE) if pain is referred to the hip
Lumbar spine pathology (e.g., spondylolysis).
Management
Initial Management:
Rest is paramount
Discontinuation of the offending activity
Application of ice to reduce pain and swelling
Analgesics, typically non-steroidal anti-inflammatory drugs (NSAIDs) like ibuprofen or naproxen, for pain and inflammation control
Crutch assistance may be required if ambulation is painful.
Conservative Management:
Most pelvic apophyseal avulsions heal well with conservative management
This involves a period of rest and progressive rehabilitation
Gradual return to activity is guided by pain resolution and restoration of strength and range of motion
Physical therapy is essential, focusing on stretching of the involved muscle group and strengthening of core and hip musculature
This typically takes 4-8 weeks, depending on the severity and location.
Surgical Management:
Surgical intervention is rarely indicated and is reserved for cases with significant displacement of the avulsed fragment (typically >2 cm), chronic non-union, or persistent pain and functional limitation unresponsive to conservative treatment
Open reduction and internal fixation (ORIF) may be performed using screws or suture anchors to reattach the fragment to the parent bone.
Supportive Care:
Nutritional support to ensure adequate bone healing
Psychological support to address potential frustration and anxiety related to the injury and recovery process
Education for the athlete and parents regarding the nature of the injury, treatment plan, and expected recovery timeline.
Complications
Early Complications:
Persistent pain and swelling
Hematoma formation
Nerve irritation if the avulsed fragment impinges on a nearby nerve
Risk of re-injury if return to sport is premature.
Late Complications:
Chronic pain
Limp
Development of non-union if the fragment fails to heal
Malunion with deformity
Premature physeal closure (rare if apophysis is already fused)
Development of scar tissue that limits muscle function.
Prevention Strategies:
Proper warm-up and cool-down routines
Gradual progression of training intensity and volume
Strength and conditioning programs focusing on balanced muscle development around the hips and core
Adequate rest and recovery between training sessions and competitions
Education for young athletes and coaches on the risks of overtraining and improper technique.
Prognosis
Factors Affecting Prognosis:
The degree of displacement of the avulsed fragment
Adherence to the rehabilitation program
Promptness of diagnosis and treatment
The specific apophysis involved
Individual healing capacity.
Outcomes:
With appropriate conservative management, most pelvic apophyseal avulsions have an excellent prognosis, with athletes returning to their previous level of activity within 4-8 weeks
Surgical cases also have good outcomes, but recovery may be prolonged.
Follow Up:
Regular follow-up appointments with the treating physician or physical therapist
Imaging may be repeated to monitor healing
Gradual progression of physical therapy exercises
Return to sport is typically staged, starting with non-contact drills and progressing to full participation as symptoms allow and strength returns
Athletes should be monitored for recurrence or late complications.
Key Points
Exam Focus:
High-yield: Most common apophyses involved (ASIS, AIIS, ischial tuberosity, iliac crest)
Mechanism of injury (sudden forceful muscle contraction)
Pain localization
Role of plain radiography, MRI
Conservative management as the mainstay
Indications for surgery (significant displacement).
Clinical Pearls:
Always consider avulsion fractures in adolescent athletes with acute hip or pelvic pain
Palpate all apophyses, not just the most tender spot
Resisted muscle testing is key to identifying the involved muscle
Remember that apophyses are unfused in skeletally immature individuals, so clinical presentation can mimic muscle strains.
Common Mistakes:
Misdiagnosing as a simple muscle strain
Delaying imaging
Premature return to play without full rehabilitation
Inadequate pain management
Overlooking associated injuries
Not considering surgical intervention in cases of significant displacement.