Chris G. Koutures, MD, FAAP Pediatric and sports medicine specialist

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Comprehensive blend of general pediatric and sport medicine care with an individualized approach that enhances the health and knowledge of patients and their families



Proud physician:
USA Volleyball Mens/Womens National Teams
CS Fullerton Intercollegiate Athletics
Chapman University Dance Department
Orange Lutheran High School

Co-Author of Acclaimed Textbook

Pediatric Sports Medicine: Essentials for Office Evaluation

Orange County Physician Of Excellence, 2015 and 2016


Potential Signs of a Serious Knee Injury in Young Athletes

Suffering a knee injury can put a sudden damper on athletic activities and even influence the ability to get around the house and attend school. The following article does not attempt to make individual diagnoses, but rather to list some potential findings that suggest a more serious knee injury in a younger athlete.

  • Immediate and large swelling above the knee cap
    • Rapid onset of swelling within the first hour after an injury that is located about the kneecap is called a suprapatellar effusion and may be the result of significant damage within the knee joint.
    • Common injured structures that lead to a suprapatellar effusion include:
      • Torn ligaments (Anterior or Posterior Cruciate Ligaments)
      • Dislocated kneecap
      • Fracture of the lowest part of the thigh bone or the top part of the shin bone
      • Disruption of the cartilage that covers the end of the thigh bone or top of the shin bone
      • Torn meniscus (shock absorbing pad on inside or outside of joint between thigh bone and shin bone) may occasionally lead to a large swelling, but not as common as other injuries
    • Any large scale swelling of the knee accompanied by fever, chills, redness at the knee joint and/or obvious warmth to the touch may suggest an infected joint and is a medical emergency requiring immediate medical evaluation in an emergency room equipped with orthopedic specialist coverage.


  • Inability to fully straighten the injured knee
    • Lack of full knee extension may be caused by the following injuries:
      • Disruption of the knee extensor apparatus, which includes the quadriceps muscles in front of the thigh, the kneecap, and the patellar tendon which connects the kneecap to the shin bone.
      • A torn meniscus or ligament that is displaced and is trapped between the thigh bone and the shin bone
    • Trying to walk on a knee that lacks full extension may cause further and possibly permanent damage to the joint cartilage. Thus, any injured athlete who cannot fully straighten the knee should use crutches until having an appropriate medical evaluation and regaining the ability to fully straighten the knee


  • Open skin at the injury site
    • Disruption of the skin, even the smallest of cuts or abrasions, may represent an open fracture that requires immediate medical attention from an emergency room visit to prevent more serious infection and a complicated recovery course.


  • Big time pain, numbness, weakness, or tingling below the knee
    • Any pain that seems out of control, or any findings of numbness and tingling below the knee or weakness of the foot or ankle muscles could suggest more serious damage to the knee or the nerves and blood vessels around the knee and indicates the need for emergency medical evaluation.


  • The young athlete who tries to play on an injured knee but just isn't as fast, as aggressive, or as graceful and ends up limping during activity
    • There may not be swelling, lack of extension, fever/chills, open skin, or big-time pain, weakness or numbness and tingling, but still seeing young athlete limp and not play at the best due to knee injury are both signs of a potentially more serious knee injury. 
    • Removing the athlete from play and seeking pediatric sports medicine specialist evaluation is highly recommended before allowing a return to play.

In any case of a suspected serious knee injury in young athletes, removal from play, placing on crutches, and seeking appropriate medical attention are all sensible initial steps for parents and families. Obtaining an accurate diagnosis and comprehensive treatment plan in an efficient manner is paramount for optimal long-term function and healing.  If any doubts after a knee injury to a young athlete, do not hesitate to contact your sports medicine specialist provider or head to the emergency room if necessary.