Skip to content
Inciteful Med

Symptoms, Deformities, and Complications

Last updated:

Multiple osteochondromas (HME) cause benign bone bumps that most often grow near the joints of long bones during childhood. While some cause no issues, others can lead to pain, nerve compression, and bone deformities like leg length discrepancies or forearm bowing that require medical monitoring.

Key Takeaways

  • • Osteochondromas commonly develop near the joints of long bones like the knees, shoulders, and ankles.
  • • The bumps can interfere with childhood bone growth, potentially causing deformities like ulnar shortening or leg length discrepancies.
  • • Hidden complications can include chronic mechanical pain, nerve compression, inflamed bursas, and rarely, blood vessel issues.
  • • Physical activity is encouraged, but high-impact contact sports may require modifications to prevent fracturing the bumps.
  • • Bone bumps generally stop growing once adulthood is reached, shifting the focus to managing joint health and pain.

Multiple Osteochondromas can vary significantly from person to person. While some individuals may only have a few bumps that never cause issues, others may face challenges that require medical attention [1][2]. Understanding the symptoms and potential complications is the first step in managing them effectively.

Where do the bumps grow?

The bumps, or osteochondromas, most commonly develop near the metaphysis—the part of a long bone closest to the joint [3][4].

  • Common Sites: The knees (distal femur and proximal tibia), shoulders (proximal humerus), and ankles are the most frequent locations [5][4].
  • Other Sites: They can also appear on “flat” bones like the pelvis (hips), the ribs, and occasionally the spine [6][7].

Bone Deformities: Changes in Alignment

As these bumps grow near the growth plates, they can sometimes interfere with how the bone develops. This is most common during childhood growth spurts [8]. (See Treatment Options for how these are corrected).

The Forearm (Ulnar Shortening)

One common deformity involves the forearm. The ulna (one of the two bones in the forearm) may grow more slowly than the other bone (the radius), leading to ulnar shortening [9]. This can cause the wrist to tilt or, in some cases, cause the radial head at the elbow to move out of its socket [10].

The Legs and Hips

  • Genu Valgum: Often called “knock-knees,” this happens when the knees tilt inward toward each other [4].
  • Leg Length Discrepancy: Sometimes, one leg may grow slightly shorter than the other [11].
  • Coxa Valga: This refers to a specific angle change in the hip bone, which can sometimes lead to hip pain or stiffness [6].

“Hidden” Complications

Not all symptoms are visible from the outside. Some complications occur when a bump presses on nearby structures.

  • Pain: This is the most common symptom. Pain can be “mechanical” (the bump rubbing against a muscle) or chronic [12][13].
  • Nerve Compression: If a bump grows near a nerve, it can cause tingling, numbness, or weakness in the hand or foot (similar to “your foot falling asleep,” but persistent) [14][13].
  • Vascular Issues: In rare cases, a bump may press on a blood vessel. This can cause a pseudoaneurysm—a localized bulge or ballooning in the wall of a blood vessel caused by the friction of the bone bump [15]. While this sounds alarming, it is not always an immediate emergency; it is something a vascular surgeon can evaluate and repair safely [15][16].
  • Bursitis: The body sometimes tries to protect itself from a bump by forming a fluid-filled sac over it, called a bursa. If this sac becomes inflamed, it is called bursitis, which can be quite painful [3].

Living with HME: Sports and Physical Activity

A major concern for parents is whether their child can participate in sports. The short answer is: Yes, but with thoughtful modifications.

  • General Activity: Staying active is encouraged to maintain muscle strength and joint flexibility [17].
  • Contact Sports: High-impact contact sports (like tackle football or hockey) carry a higher risk because a direct blow to an osteochondroma can cause it to fracture or break [18]. Your doctor may recommend low-impact alternatives or suggest specific protective padding over prominent bumps. Always discuss sports clearance with your orthopedic team.

Childhood vs. Adulthood

The way the condition feels can change as you get older.

Stage What to Expect
Growing Years Focus is on the appearance of new bumps and monitoring bone alignment and leg length [8][19].
Adulthood Bumps generally stop growing. The focus shifts to managing chronic pain, joint wear-and-tear (osteoarthritis), or monitoring for rare changes in the bumps [2][20].

It is important to remember that most of these issues can be treated or managed. Regular check-ups allow your orthopedic team to catch these changes early.

Frequently Asked Questions

Where do multiple osteochondromas usually grow?
The bone bumps typically develop near the growth plates of long bones. The most common locations include the knees, shoulders, ankles, and sometimes flat bones like the hips or ribs.
How do multiple osteochondromas affect bone growth?
Because the bumps grow near the growth plates, they can interfere with normal bone development in children. This can lead to issues like forearm bowing, knock-knees, or one leg growing slightly shorter than the other.
What causes the pain associated with multiple osteochondromas?
Pain is the most common symptom and can happen when a bump rubs against a muscle or tendon. It can also be caused by the bump pressing on nearby nerves, or by an inflamed fluid sac over the bump, known as bursitis.
Can my child play sports with multiple osteochondromas?
Yes, staying active is highly encouraged to maintain muscle strength and joint flexibility. However, high-impact contact sports carry a risk of fracturing the bone bumps, so your doctor may recommend low-impact alternatives or protective padding.
Will the bone bumps continue to grow in adulthood?
During childhood, the focus is on monitoring the appearance of new bumps and tracking bone alignment. In adulthood, the bumps generally stop growing, and medical care shifts toward managing chronic pain or joint wear-and-tear like osteoarthritis.

Questions for Your Doctor

  • • What is my child’s current measurement for leg length discrepancy, and how will we monitor this over time?
  • • Are any of the bumps currently located near major nerves or blood vessels that we should watch closely?
  • • Is the ulnar shortening in my child's forearm at a point where we need to discuss corrective surgery?
  • • What are your specific recommendations regarding contact sports or high-impact activities for my child?
  • • At what point would you recommend a referral to a specialized pain management or physical therapy team?

Questions for You

  • • Does my child seem to favor one leg more than the other when they are tired?
  • • Have I noticed any changes in how my child holds their wrist or arm while writing or playing?
  • • Are there specific bumps that seem to get irritated by clothing, backpack straps, or sports equipment?
  • • How often does pain interfere with my child’s sleep or daily activities?

Want personalized information?

Type your question below to get evidence-based answers tailored to your situation.

References

  1. 1

    Venous malformation may be a feature of EXT1-related hereditary multiple exostoses: A report of two unrelated probands.

    Albokhari D, Bailey CR, Hwang F, et al.

    American journal of medical genetics. Part A 2023; (191(6)):1570-1575 doi:10.1002/ajmg.a.63158.

    PMID: 36869625
  2. 2

    Imaging of benign complications of exostoses of the shoulder, pelvic girdles and appendicular skeleton.

    Gavanier M, Blum A

    Diagnostic and interventional imaging 2017; (98(1)):21-28 doi:10.1016/j.diii.2015.11.021.

    PMID: 27316575
  3. 3

    Hereditary multiple exostoses: an educational review.

    Rueda-de-Eusebio A, Gomez-Pena S, Moreno-Casado MJ, et al.

    Insights into imaging 2025; (16(1)):46 doi:10.1186/s13244-025-01899-6.

    PMID: 39982564
  4. 4

    Management of Lower Extremity Deformity in Children with Hereditary Multiple Exostoses.

    Whalen MJ, van Bosse HJP

    Journal of the Pediatric Orthopaedic Society of North America 2025; (13()):100277 doi:10.1016/j.jposna.2025.100277.

    PMID: 41158744
  5. 5

    Advances in the pathogenesis and possible treatments for multiple hereditary exostoses from the 2016 international MHE conference.

    Phan AQ, Pacifici M, Esko JD

    Connective tissue research 2018; (59(1)):85-98 doi:10.1080/03008207.2017.1394295.

    PMID: 29099240
  6. 6

    One-stage surgical excision of a huge bilateral multiple osteochondroma of the hip: a case report.

    Taheriazam A, Saeidinia A

    Electronic physician 2017; (9(9)):5310-5317 doi:10.19082/5310.

    PMID: 29038715
  7. 7

    A Unique Case of Asymptomatic Osteochondroma From the Rib in Multiple Hereditary Exostoses: Insights Into Screening and Management.

    Larson LM, Morgan SJ, Guillaume TJ

    JBJS case connector 2026; (16(1)) doi:e25.00477.

    PMID: 41723865
  8. 8

    Daughter and mother diagnosed with hereditary multiple exostoses: A case report and a review of the literature.

    Mărginean CO, Meliţ LE, Mărginean MO

    Medicine 2017; (96(1)):e5824 doi:10.1097/MD.0000000000005824.

    PMID: 28072741
  9. 9

    A Rare Presentation and Management of Forearm Deformity in a Patient with Hereditary Multiple Exostoses: A Case Report.

    Agashe M, Shah A, Parikh SN

    JBJS case connector 2018; (8(3)):e53 doi:10.2106/JBJS.CC.17.00295.

    PMID: 30045076
  10. 10

    An Evaluation of Forearm Deformities in Hereditary Multiple Exostoses: Factors Associated With Radial Head Dislocation and Comprehensive Classification.

    Jo AR, Jung ST, Kim MS, et al.

    The Journal of hand surgery 2017; (42(4)):292.e1-292.e8 doi:10.1016/j.jhsa.2017.01.010.

    PMID: 28249791
  11. 11

    Lower limb deformities and limb length discrepancies in hereditary multiple exostoses.

    Madoki A, Tuerlinckx C, Rausin G, et al.

    Acta orthopaedica Belgica 2022; (88(1)):198-205 doi:10.52628/88.1.25.

    PMID: 35512172
  12. 12

    Multiple hereditary exostoses and enchondromatosis.

    Jurik AG

    Best practice & research. Clinical rheumatology 2020; (34(3)):101505 doi:10.1016/j.berh.2020.101505.

    PMID: 32253147
  13. 13

    Management of nerve compression in multiple hereditary exostoses: a report of two cases and review of the literature.

    Payne R, Sieg E, Fox E, et al.

    Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery 2016; (32(12)):2453-2458 doi:10.1007/s00381-016-3166-3.

    PMID: 27444292
  14. 14

    Multidetector computed tomography in the evaluation of hereditary multiple exostoses.

    Kwee RM, Fayad LM, Fishman EK, Fritz J

    European journal of radiology 2016; (85(2)):383-91.

    PMID: 26781144
  15. 15

    Hereditary multiple exostoses as a novel cause of bilateral popliteal artery aneurysms in the elderly.

    Ferrari EJ, Crotty RK, Eikermann-Haerter K, Stone JR

    Cardiovascular pathology : the official journal of the Society for Cardiovascular Pathology 2017; (31()):20-25 doi:10.1016/j.carpath.2017.07.001.

    PMID: 28818770
  16. 16

    Late presentation of spinal cord compression in hereditary multiple exostosis: case reports and review of the literature.

    Gigi R, Kurian BT, Cole A, Fernandes JA

    Journal of children's orthopaedics 2019; (13(5)):463-470 doi:10.1302/1863-2548.13.180130.

    PMID: 31695813
  17. 17

    Eccentric Training as an Adjunct to Rehabilitation Program for Hereditary Multiple Exostoses: A Case Report.

    Kanik ZH, Gunaydin G, Sozlu U, et al.

    Journal of clinical and diagnostic research : JCDR 2016; (10(2)):YD03-4 doi:10.7860/JCDR/2016/16898.7302.

    PMID: 27042573
  18. 18

    Multiple Exostoses Syndrome and Basilar Artery Aneurysm: A Case Report.

    Ploumis A, Liampas A, Angelidis M, et al.

    Journal of vascular and interventional neurology 2018; (10(2)):28-32.

    PMID: 30746007
  19. 19

    Rapidly acquired valgus deformity of the knee after osteochondroma resection in multiple hereditary exostoses pediatric patients: A report of two cases.

    Aitchison AH, Alcoloumbre D, Belzarena AC, Blanco JS

    Radiology case reports 2022; (17(1)):201-207 doi:10.1016/j.radcr.2021.10.037.

    PMID: 34815827
  20. 20

    Total knee arthroplasty with simultaneous tibial shaft osteotomy in patient with multiple hereditary osteochondromas and multiaxial limb deformity - a case report.

    Grzelecki D, Szneider J, Marczak D, Kowalczewski J

    BMC musculoskeletal disorders 2020; (21(1)):233 doi:10.1186/s12891-020-03245-x.

    PMID: 32284061

This page provides educational information about Multiple Osteochondromas (HME) symptoms and complications. It does not replace professional medical advice, diagnosis, or treatment from your pediatric orthopedist or healthcare team.

Stay up to date

Get notified when new research about Multiple osteochondromas is published.

No spam. Unsubscribe anytime.