Knee pain is common issue in children and teenagers, particularly between the ages of 9 – 13, as they go through growth spurts. In this article I will briefly explain growth plates and go through different conditions a child may present with when they suffer from knee pain.
Bone Growth in Children
Children’s bones have 2 different areas where bone growth occurs: growth plates (Physis) and growth centres (Apophysis). The growth plate runs across the width of the bone, near the end of the bone. The growth centres are normally in bony prominences where tendons attach onto the bone. You can see these two growth areas of the knee in a picture further on in this article.
As a child grows these growth areas layers down bone tissue so the bone can become longer and wider. However, this area of the bone is uncalcified (not strengthened by calcium) and is more a cartilage like structure. This means it is not as hard and rigid in this area and is more susceptible to injury due to trauma, or tendons pulling on these areas.
Overuse injuries are more common near growth areas as it is common for tendons to attach near these areas and pull on the un-ossified bone and cause it to pull away from the main body of bone, causing pain. This is common in children who have just gone through a sudden growth spurt, or have had a sharp increase in physical activity. Below is a list of these common conditions.
Common Overuse Conditions in Growth Areas in The Knee
Osgood Schlatter Disease
One of the more common and well-known injury is Osgood-Schlatter disease. It is caused by stress being put on the bony point on the top of the shin, called the tibial tuberosity. This stress is from the patella tendon that attaches the quadricep muscle to this bony point. The tendon causes pulling action on the unfused growth centre (apophysis) of that bony prominence that causes it to pull away from the main part of the bone causing inflammation and pain. This growth centre normally closes and fuses onto the main shin bone (tibia) during adolescence. Before this point it is made of weaker cartilage type of bone making it more susceptible to getting pulled. If your child plays repetitive type sports such as running, jumping, and squatting sports, these sports require high amounts quadricep contractions pulling on the tendon that attaches onto the bone, increasing their risk of developing Osgood-Schlatter Disease.
Diagnosis:
More common in boys
After prepubertal growth spurt
Knee pain on the bony prominence below the knee
Pain is worse with activity
Can be in both knees, around 25-30% people have it in both
Pain with running, squatting, sitting in a chair, going down the stairs
Treatment:
Treatment is self-limiting as resolves when the growth centre ossifies. The focus of treatment is to reduce pain, and to modify activities to prevent aggravating the condition. The child will then slowly increase activity, using pain as a guide, to return to normal activities and sport.
Ice, analgesics ie Ibuprofen gels
Decrease activity and sport for 2-3 months
Change to sport with less knee extension, such as swimming or golf
Stretching should focus on the quadriceps, hamstrings, and iliotibial band to offload the patella tendon
Strengthening the Quads, calfs and hamstrings may help
Massage to reduce tightness in quadriceps muscles
Prognosis is excellent. Only 10% last longer than a year
Strengthening ankle and hip muscles may help reduce the load going through the knees. Surgery is very rarely needed, and should only be used if the child has symptoms when he is older and the growth centers has fused and it now fully ossified bone.
Sindings-Larsen Johansson Syndrome
This condition is very similar to Osgood Schlatter’s disease and may get mis-diagnosed as this. Rather than the pain being felt on the bony prominence at the top of the shin bone, it is felt on the bottom of the knee cap.
Other common overuse conditions in growth areas
There are other areas of the body that can have pain in growth areas.
Severs Disease
This condition is at the back of the heel where the Achilles pulls on the back of the calcaneus bone where a growth plate is present. The plantar fascia also connects to the other side of this growth plate. It is common in children in 9-12 years of age.
Diagnosis:
The clinical exam is notable tenderness over calcaneal insertion of Achilles tendon and a positive squeeze test, where there is pain when you squeeze either side of the heel bone. Diagnosis is clinical and does not require imaging studies. It is important to differentiate this condition from more sinister injuries such as a calcaneal fracture.
Treatment:
This condition is also self-limited. Treatment includes activity modification which is guided by pain. Symptoms may be managed with ice, anti-inflammatory medications like ibuprofen. Heel cups or heel lifts may be of help to reduce stretch caused by the calf muscles. In severe cases a cast/boot maybe needed to offload the bone and stop the muscles pulling in it. A physio programme will focus on plantar fascia and calf stretching and strengthening. Addressing underlying biomechanical factors should also be considered.
Little League Elbow
As you can probably tell from the name, this injury is more common in America with children playing baseball. This condition takes place at the inside of the elbow at the medial epicondyle of the humerus. This is bony prominence on the inside of your elbow. There is a growth centre here that closes around the age of 15-16 years of age. Therefore, this injury is common in children aged 9-14, before the growth centre fuses.
This injury is common in overhead throwing sports such as baseball and Javelin. The mechanics of throwing causes the elbow to go through a ‘valgus’ force where the inside of the elbow gets stretched and the outside of the elbow gets compressed. The stretching of the inside of the elbow causes tendon and ligament to pull on the medical epicondyle growth centre, pulling it away from the main body of the bone, causing pain.
It is important to differential more serious injuries in this area. If there is an older teenager with this pain, who’s growth centre is fused, there is more chance of a ligament being torn, or an avulsion fracture, where the tendon pulls a small part of the bone off. The compression on the outside of the elbow can also cause injuries as that pressure can cause cartilage or bone damage.
The list above is not exhaustive, there are other conditions that could be causing knee pain. If you have any concerns about your child’s knee pain, then book them in to see a healthcare professional.
Thanks for reading
James McMurray
Sport and Exercise Health Science BSc
Physiotherapy BSc
Disclaimer:
This is not medical advice. The content is intended as educational content only. If you have any heel pain that is not getting better, then you should seek care of a medical professional.
References:
ELIZABETH ROTH, MD; MICHAEL MIROCHNA, MD; and DAVID HARSHA, MD, CAQSM, St. Vincent Hospital, Indianapolis, Indiana, Am Fam Physician. 2012 Sep 15;86(6):569-570.
Howard R. Diagnosing and treating Sever's disease in children. Emerg Nurse. 2014 Sep;22(5):28-30
Klingele KE, Kocher MS. Little league elbow: valgus overload injury in the paediatric athlete. Sports Med. 2002;32(15):1005-15. doi: 10.2165/00007256-200232150-00004. PMID: 12457420.
Bruns, J., Werner, M., & Habermann, C. (2018). Osteochondritis Dissecans: Etiology, Pathology, and Imaging with a Special Focus on the Knee Joint. Cartilage, 9(4), 346–362. https://doi.org/10.1177/1947603517715736
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