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Basics ⬇

Author: Brittney M.Richardson, MD, CAQSM

Description

Injury to the abdominal wall musculature, including the rectus abdominis, internal/external obliques, and transverse abdominis muscles:

  • Typically a noncontact injury but may be caused by trauma
  • Can be acute or subacute.
  • Acute injury typically is the result of an abrupt movement of the trunk.
  • Subacute injury caused by repetitive activity
  • A specific variant known as a side strain most commonly involves the internal oblique at or near the inferior rib attachments.

Epidemiology

Somewhat uncommon injuries, but specific sports have a higher prevalence:

  • Account for <2% of athletic injuries (1)
  • Sports with repetitive trunk rotation have higher rates:
    • Soccer, tennis, baseball, ice hockey, gymnastics, pole vault, cricket, bowling (2)
  • Seen in runners, because the abdominal muscles are used for pelvic stabilization
  • Attributed to weight training and abdominal workouts as well

Etiology and Pathophysiology

Acute or chronic muscle-tendon injury of the abdominal wall musculature from a sudden intrinsic eccentric contraction of the abdominal musculature (3)

Risk-Factors

  • Poorly conditioned abdominal musculature or deficits in core strength
  • Previous abdominal wall muscle strain/tear
  • Poor weight training or conditioning techniques
  • Participation in activities that require abrupt and/or repetitive movements of the torso early in the sport season

General Prevention

Appropriate weight training and conditioning techniques with attention to core strength

Diagnosis ⬆ ⬇

History

  • Acute abdominal wall pain associated with stretching or twisting mechanism
  • Chronic pain due to repetitive activity of the trunk or torso
  • Direct trauma associated with a minority of these injuries
  • Pain usually focal and exacerbated by specific movements or positions
  • Pain with active contraction of affected muscle during sneezing or coughing
  • Symptoms generally subside in the absence of activity.
  • In throwing or overhead athletes typically on the side contralateral to the throwing arm, in baseball batters contralateral to the dominant batting side (4)

Physical Exam

  • Appearance is typically normal with swelling and evidence of contusion rare in the absence of preceding trauma.
  • Splinting may be noted if pain is severe.
  • Tenderness of the abdominal wall is usually focal and discrete but may be more diffuse in overuse injuries.
  • Muscle defect may be notable if an associated tear or herniation is present.
  • Peritoneal signs are absent.
  • Symptoms are reproduced by contraction of the affected muscle.

Differential Diagnosis

  • Abdominal wall contusion
  • Abdominal wall hematoma:
    • Swelling, periumbilical contusion, and a mass with rigidity and/or guarding are signs of a rectus sheath hematoma.
  • Abdominal wall hernia (umbilical, spigelian)
  • Intra-abdominal injury (contusion, laceration, perforation)
  • Intra-abdominal process (e.g., infection, mass)
  • Iliac apophysitis
  • Osteitis pubis

Diagnostic Tests & Interpretation

  • Typically not indicated (5)[C]
  • Plain films, computed tomographic (CT) scan indicated if there is concern for rib fracture or intra-abdominal process
  • Magnetic resonance imaging (MRI) can be used to assess for muscle tear or to assess the extent of injury:
    • Reserved for more severe injuries
  • Musculoskeletal ultrasound (US) can help confirm the diagnosis of muscle tear or hematoma and aid in clinical follow-up (3)[C].

Treatment ⬆ ⬇

Acute treatment:

  • Remove the athlete from the offending activity.
  • Ice
  • Compressive wrap
  • Nonsteroidal anti-inflammatory drugs (NSAIDs) or acetaminophen PRN only
  • Once pain subsides, a rehabilitation program may be initiated (1,6)[C].

Medication

First Line

NSAIDs or acetaminophen:

  • Avoid NSAIDs if there is concern for bleeding or hematoma.

Second Line

Low-dose opioids or muscle relaxants may be used for more severe injuries but are rarely needed. Use should be limited to 3 days.

Additional Therapies

  • Rehabilitation:
    • Assess abdominal muscle strength and core strength/stability.
    • Initiate a rehab program once pain has subsided:
      • Start with passive stretching.
      • Advance to strengthening activities as tolerated with isometrics starting 5 to 7 days; concentrics at day 12; and advancement to eccentrics, core strength, and plyometrics (4)[C].
      • Progress to sport-specific activities (1,6)[C].
  • Modalities such as US or muscle stimulation may help alleviate symptoms.
  • Thoracic spine mobilization may help restore unrestricted motion.
  • Platelet-rich plasma injection at the site of injury may help improve pain relief and introduce growth factors to the injured muscle group (3)[C].
  • Corticosteroid injection at the site of muscle tear/strain may be considered for acute pain relief or refractory cases.

Surgery/Other Procedures

Surgery may be necessary in cases of rectus sheath hematoma, hernia, or intra-abdominal process.

Ongoing Care ⬆ ⬇

Follow-up Recommendations

  • The athlete may return to activity once pain subsides and he or she can engage in sport-specific activity.
  • Side strain–type injury has been reported to take up to 30 days in some athletes.

Prognosis

Overall prognosis for recovery is excellent:

  • Duration of symptoms is variable and may persist for months.
  • Recurrence rates are high (>20%).

References ⬆ ⬇

  1. Johnson R. Abdominal wall injuries: rectus abdominis strains, oblique strains, rectus sheath hematoma. Curr Sports Med Rep. 2006;5(2):99–103.
  2. Nealon AR, Cook JL. Trunk side strain has a high incidence in first-class cricket fast bowlers in Australia and England. Clin J Sport Med. 2018;28(3):284–288.
  3. Dauty M, Menu P, Dubois C. Uncommon external abdominal oblique muscle strain in a professional soccer player: a case report. BMC Research Notes. 2017;7:684.
  4. Nealon AR, Kountouris A, Cook JL. Side strain in sport: a narrative review of pathomechanics, diagnosis, imaging and management for the clinician. J Sci Med Sport. 2017;20(3):261–266.
  5. Cartwright SL, Knudson MP. Diagnostic imaging of acute abdominal pain in adults. Am Fam Physician. 2015;91(7):452–459.
  6. Maquirriain J, Ghisi JP, Kokalj AM. Rectus abdominis muscle strains in tennis players. Br J Sports Med. 2007;41(11):842–848.

Clinical Pearls ⬆

  • Athletes can return to play when there is minimal-to-no tenderness, normal muscle strength and stamina, and can perform sport-specific tasks.
  • Usual duration of symptoms varies from weeks to months.