Osgood-Schlatter: Teen Knee Pain and the Bump Below the Kneecap

Your 12-year-old points at a lump just below his kneecap and says it hurts. It hurts most going up stairs, landing from a jump, and kneeling on a hard floor. It settles overnight and comes back within twenty minutes of basketball practice. Press on it and he flinches. The other knee has a smaller version of the same bump.

This is Osgood-Schlatter, and it turns up in a predictable window. A Dutch general practice cohort published in the British Journal of General Practice in 2022 by van Leeuwen and colleagues recorded an incidence of 3.8 cases per 1000 person-years in those aged 8 to 18. Incidence peaked at 13.8 per 1000 person-years in boys at age 12, and 6.0 in girls at age 11. Boys ran at 4.9 overall, girls at 2.7.

Most parents are told the same thing at this point. He will grow out of it. That is partly accurate and it leaves out the part that changes what you do this season.

What the bump actually is

The thigh muscles at the front of the leg, the quadriceps, join into the kneecap. Below the kneecap, the patellar tendon carries that pull down onto the top of the shin bone. It attaches at a small raised area called the tibial tubercle.

In a growing child that attachment point is not solid bone. It is a growth plate, an apophysis, made of cartilage that hardens into bone over several years. Cartilage tolerates pulling force less well than finished bone does.

During a growth spurt, two things happen at once. The long bones lengthen faster than the muscles and tendons adapt to the new length, so the pull across that attachment increases. At the same time the growth plate is at its most active and least tolerant. Add jumping, sprinting, and hard stops from basketball, volleyball, soccer, or gymnastics, and the tendon repeatedly tugs at a site that is already under strain.

The body responds by laying down extra bone at the tubercle. That is the lump. It is the reason the bump stays after the pain goes, and it is why the knee is tender to direct pressure long before it is tender to anything else.

Both knees are involved in a sizeable share of cases. One side is usually worse.

Why "he will grow out of it" is incomplete

The growth plate does close. Once it fuses into solid bone, the specific mechanism that causes Osgood-Schlatter pain stops operating. In that narrow sense the advice holds.

What it skips is what happens in between, and what happens afterward.

A 2025 national cohort study in Sports Medicine by Krommes and colleagues followed 397 Danish adults who had been seen in secondary care for adolescent Osgood-Schlatter between 1977 and 2020. 73% reported ongoing pain or problems from the tibial tubercle area. 85% still had a prominent bony bump. Their Knee Injury and Osteoarthritis Outcome Score subscales sat below healthy population estimates across all age groups, with the largest gaps in the sport and recreation and quality of life sections. The study reported a raised risk of patellar tendon problems and of meniscal injury compared with population figures.

The authors also found that longer symptom duration and higher pain during adolescence tracked with worse knee health decades later.

Two cautions on reading that. These were patients referred into hospital care, so they represent a more affected group than a child seen once by a family doctor. And an association between a longer teenage episode and a worse adult knee does not prove that shortening the episode changes the adult outcome. Nobody has run that trial.

What it does establish is that the condition deserves a plan. Waiting it out for two or three years while a child stops playing the sport they love has a cost, and the reassurance that it all resolves by itself is not well supported by the long-term data.

Complete rest is rarely the answer

Rest is still the most common prescription. In that Dutch cohort, at a first consultation the family doctor gave advice 61.0% of the time, rest 23.5%, and imaging 17.5%. Across all consultations, physiotherapy was involved in 13.4%.

Rest works while it lasts. The tendon stops pulling on an irritated growth plate, and the pain settles. The problem arrives on the return. The knee comes back weaker, the child has lost conditioning, the tendon tolerates less than it did before, and the same sport at the same intensity reproduces the same symptoms within a fortnight. Families often cycle through this several times before anyone suggests something else.

Rathleff and colleagues tested the alternative in 2020, published in Orthopaedic Journal of Sports Medicine. They enrolled 51 adolescents aged 10 to 14, 51% female, and ran a 12-week programme built from a graded activity ladder governed by pain response plus knee strengthening exercises, with a staged return to sport.

The results:

• 80% reported a successful outcome at 12 weeks
• 90% reported a successful outcome at 12 months
• Median pain fell from 7 out of 10 at baseline to 2 out of 10 at 12 weeks
• Knee extension strength rose 32% and hip abduction strength rose 24% over the 12 weeks

The authors put their conclusion carefully. The approach "may offer an alternative to passive approaches such as rest or wait-and-see, often prescribed for adolescents with OSD."

Be honest about what that study is. A prospective cohort with 51 participants and no control group cannot prove the programme beat rest, because there was no rest group to beat. A randomised trial comparing this kind of self-management against usual care, the SOGOOD trial, was registered with a published protocol in BMC Sports Science, Medicine and Rehabilitation in 2024 by Krommes and colleagues, which tells you the question is still genuinely open.

So the position is this. Managed loading has cohort evidence behind it, a clear mechanism, and the advantage of keeping a child in sport. Blanket rest has custom behind it. Given the choice, most clinicians now start with the first.

The loading and strength programme

The principle is that the tendon and growth plate need enough load to stay strong and not so much that they stay irritated. Finding that line is the whole job, and a number does it better than a feeling.

Use a pain scale, not a yes or no question. The Rathleff protocol allowed activity while pain stayed at or below 2 out of 10 during the activity and the following morning. That second check matters more than the first. A child will push through 6 out of 10 during a game and pay for it at breakfast. Ask the morning-after question every day and write the number down.

Build strength through the front of the thigh and the hip. The early weeks of that protocol used simple holds: bridging, and static knee extension holds, three sets of ten. From week five it progressed to wall squats, then squats and lunges, with harder and easier versions available depending on the day. Hip abduction strength rose alongside knee strength, which is why the hip gets included rather than treated as unrelated.

Progress by steps, and allow steps backward. The activity ladder had eleven levels, running from gentle movement up to full competitive sport. A child moves up when the pain numbers stay inside the limit, and drops back a level when they do not. Return to sport sat at level eight, and only after training had stayed comfortable.

Expect the timeline in months. The programme ran twelve weeks and the results kept improving out to a year. A parent hoping for a fix in two weeks will abandon a plan that was working.

Loading stays inside a range the knee tolerates today, and that range widens as strength builds. That principle carries across to the adult tendon problems this condition sits beside, including patellar tendinopathy, or jumper's knee, and it is the same logic that drives the rebuild in patellofemoral pain in runners.

The sport decision, and how to talk to the coach

Most families arrive at the same fork. There is a season on, the child wants to play, and the knee hurts.

Pulling a 13-year-old out of their sport for a year is a real cost. It removes their exercise, most of their social life, and part of how they see themselves. Weigh that honestly rather than treating rest as the safe default.

The workable middle is usually a reduction in volume rather than a stop. Practice twice a week instead of four times. Skip the jumping and plyometric drills while keeping ball skills. Play half a game. Drop the second sport and keep the first. Sit out the tournament and keep the weekly practice. These are all more sustainable than a season off, and they give you something to adjust rather than a switch to flip.

For the conversation with a coach, be specific and give them a rule they can apply without you there:

• Name the condition and say it is a growth plate issue, not a torn structure
• Give the specific restriction: no jumping drills, or 30 minutes maximum, or no full-court sprints
• Give them the pain rule, so a decision can be made at practice without a phone call
• Set a review date so the coach knows the restriction is temporary and will be revisited
• Ask them to tell you when the child limps or stops mid-drill, because kids underreport to coaches

A coach who understands the plan usually protects it. A coach who hears only "his knee hurts" will ask the child how it feels and get "fine" as the answer.

What the bump means long term

The lump is permanent in most cases. 85% of the adults in the Danish cohort still had a prominent tubercle. It is extra bone laid down at the attachment site, and once it is there it stays. Once the growth plate closes, that bone is no longer a pain generator on its own.

Two practical consequences follow. Kneeling directly on the bump stays uncomfortable for some adults, which matters for flooring, tiling, gardening, and some trades. And in a small number of cases a fragment of bone sits separately within the tendon and keeps causing pain after growth finishes, which is the situation where an orthopaedic surgeon becomes involved. That is uncommon and it is a conversation for after skeletal maturity.

The cosmetic question comes up with teenagers who do not want a visible lump. The honest answer is that it stays, that it becomes less noticeable as the leg grows around it, and that it is not a marker of damage.

Telling it apart from the conditions that look similar

Three problems in this age group produce anterior knee pain during jumping sports. Where the tenderness sits separates them, and a physiotherapist finds that by pressing in specific places.

Osgood-Schlatter is tender at the tibial tubercle, the raised area on the shin about two to three finger-widths below the bottom of the kneecap. There is a palpable bump. Typical age is 10 to 15, during or just after a growth spurt.

Sinding-Larsen-Johansson syndrome is tender at the bottom tip of the kneecap itself, where the tendon starts rather than where it ends. It is the same kind of growth plate irritation at the other end of the same tendon. It tends to appear a little earlier, around 10 to 13, and there is no bump on the shin.

Patellar tendinopathy is tender in the tendon between those two points, and it is a problem in the tendon tissue rather than a growth plate. It is more common once the growth plates have closed, so it is the likelier answer in an older teenager or a young adult with the same jumping history. It also responds to a different loading approach, which is covered in the jumper's knee post.

All three overlap in presentation and all three can occur together. Age, growth stage, and the exact point of tenderness do most of the sorting.

Imaging is usually unnecessary. The Dutch cohort recorded imaging at 17.5% of first consultations, and the authors flagged a gap between guideline advice and practice on exactly that point. An X-ray is reserved for an unclear picture, a history that does not fit, or a suspicion of something else.

What a first visit looks like

A first physiotherapy appointment for teenage knee pain runs mostly on history and hands. Your therapist will ask when the pain started, how it relates to the growth spurt, which activities set it off, how long it lasts afterward, what the mornings are like, and what the sporting calendar looks like for the next few months. That last question shapes the plan more than any test does.

The physical part involves pressing along the tendon and its two attachment points to locate the tenderness precisely, checking knee and hip strength, watching a squat and a single-leg landing, and assessing quadriceps and hamstring length, which often shortens during a growth spurt.

You should leave with three things: a pain number that defines the daily limit, two or three exercises, and a clear statement of what happens at practice this week. Expect the plan to change at the next visit, because how the knee responds over the first fortnight is the most useful information available.

Involve the teenager directly in this. They are the one tracking the number and doing the exercises. A plan the parent owns and the child tolerates tends to stop within a month.

Physiotherapy is a direct-access profession in British Columbia, regulated by the College of Health and Care Professionals of BC, so you can book an assessment for your child without a physician's referral. Some extended-health plans require a referral for reimbursement, so check your policy before the first visit. If a child is covered under a parent's plan, confirm the dependant age limit as well.

When to see a physician instead

Some patterns point away from a growth plate overload problem and need a doctor rather than a physiotherapist.

• Pain that wakes the child from sleep, or that is present at rest and not linked to activity
• Knee pain together with fever, or with feeling generally unwell
• Unexplained weight loss
• A limp with no clear injury, or a child who refuses to bear weight
• A knee that is hot, red, or swollen across the joint rather than tender at one point
• Pain that began with a single sudden incident rather than building up over weeks

These features need medical assessment, because conditions affecting bone, joints, and general health in this age group can present as knee pain. Hip problems in children commonly refer pain to the knee, so a child with knee pain and a limp needs the hip examined.

This article is general information, not personal medical advice. A regulated practitioner can confirm whether the patterns described apply to you.

Frequently asked questions

What is Osgood-Schlatter disease?

Osgood-Schlatter is irritation of the growth plate where the patellar tendon attaches to the top of the shin bone, at a raised area called the tibial tubercle. Repeated pulling from the thigh muscles during running and jumping irritates that attachment while it is still cartilage rather than finished bone. The body lays down extra bone in response, which creates the tender lump below the kneecap. It appears most often during a growth spurt in children aged 10 to 15.

How common is it and who gets it?

A 2022 Dutch general practice cohort published in the British Journal of General Practice recorded 3.8 cases per 1000 person-years among those aged 8 to 18. Incidence peaked at 13.8 per 1000 person-years in boys at age 12 and 6.0 in girls at age 11, giving overall rates of 4.9 in boys and 2.7 in girls. It concentrates in children playing jumping and sprinting sports such as basketball, volleyball, soccer, and gymnastics.

Will my child grow out of it?

The specific mechanism does stop once the growth plate closes, so the condition has a natural end point. A 2025 Danish national cohort study of 397 adults seen in secondary care for adolescent Osgood-Schlatter found 73% reported ongoing pain or problems from the tibial tubercle area and 85% still had a bony bump, with knee scores below population estimates. That group was hospital-referred and more affected than average, so it overstates the picture for a typical case. The practical point is that a plan beats waiting.

Does my child have to stop playing sport?

In most cases, no. Reducing volume usually works better than stopping. That might mean fewer practices per week, skipping jumping drills while keeping skill work, playing half a game, or dropping a second sport. A 2020 prospective cohort study of 51 adolescents used a graded activity ladder with a staged return to sport rather than rest, and 80% reported a successful outcome at 12 weeks. Your physiotherapist will set the specific limits.

Is rest the right treatment?

Rest settles the pain while it continues, and symptoms often return within weeks of going back to sport because the knee comes back weaker. The authors of the 2020 Orthopaedic Journal of Sports Medicine cohort study described their activity modification and strengthening programme as an alternative to "passive approaches such as rest or wait-and-see, often prescribed for adolescents with OSD." A randomised trial comparing self-management against usual care was registered with a published protocol in 2024, so the direct comparison is still being tested.

How do we know how much activity is safe?

Use a pain number rather than a yes or no question. The 2020 protocol allowed activity while pain stayed at or below 2 out of 10 during the activity and the following morning. The morning-after check catches what a motivated child will push through during a game. Record the number daily, and use it to decide whether the next step up or down the activity ladder is appropriate.

What exercises help?

The 2020 protocol began with bridging and static knee extension holds at three sets of ten in the first four weeks, then progressed to wall squats, squats, and lunges from week five, with easier and harder versions available. Over 12 weeks, knee extension strength rose 32% and hip abduction strength rose 24%. Hip work is included because the hip controls how load reaches the knee during landing. A physiotherapist will select and progress the specific exercises for your child.

How long does it take to improve?

In the 2020 cohort study, 80% of the 51 adolescents reported a successful outcome after the 12-week programme, rising to 90% at 12 months, with median pain falling from 7 out of 10 to 2 out of 10 by 12 weeks. Plan in months rather than weeks. Recovery speed depends on growth stage, how irritable the knee is at the start, the sporting demands, and how consistently the programme is followed.

Will the bump go away?

Usually not. The lump is extra bone at the attachment site, and in the Danish cohort 85% of adults still had a prominent tubercle decades later. It becomes less noticeable as the leg grows, and once the growth plate closes it generally stops being a source of pain. Kneeling directly on it can stay uncomfortable for some adults, which is worth knowing for trades and activities that involve kneeling on hard surfaces.

How is it different from jumper's knee or Sinding-Larsen-Johansson?

The three are separated mainly by where the tenderness sits. Osgood-Schlatter is tender at the tibial tubercle on the shin, below the kneecap, with a palpable bump. Sinding-Larsen-Johansson is tender at the bottom tip of the kneecap, at the other end of the same tendon, and typically appears a little earlier at around 10 to 13. Patellar tendinopathy is tender in the tendon between those two points and is more common after the growth plates close.

Does my child need an X-ray?

Usually not. The diagnosis is normally made from the history and by pressing on the tender area. The 2022 Dutch cohort recorded imaging at 17.5% of first consultations and the authors noted a gap between guideline advice and what happens in practice on this point. Imaging is reserved for an unclear picture, symptoms that do not fit the usual pattern, or when another condition needs ruling out.

Do I need a referral to see a physiotherapist in BC?

No. Physiotherapy is a direct-access profession in British Columbia, regulated by the College of Health and Care Professionals of BC, so you can book an assessment for your child without a physician's referral. Some extended-health insurance plans require a referral for reimbursement even though the profession does not, so confirm with your insurer first. If your child is covered as a dependant, check the age limit on that coverage at the same time.

Sources

• van Leeuwen et al., "Incidence and management of Osgood-Schlatter disease in general practice: retrospective cohort study," British Journal of General Practice, 2022
• Rathleff et al., "Activity Modification and Knee Strengthening for Osgood-Schlatter Disease: A Prospective Cohort Study," Orthopaedic Journal of Sports Medicine, 2020
• Krommes et al., "Long-Term Knee Health in Adults with a History of Adolescent Osgood-Schlatter: A National Cohort Study of Patients in Secondary Care in Denmark 1977-2020," Sports Medicine, 2025
• Krommes et al., "Self-management including exercise, education and activity modification compared to usual care for adolescents with Osgood-Schlatter (the SOGOOD trial): protocol of a randomized controlled superiority trial," BMC Sports Science, Medicine and Rehabilitation, 2024
• College of Health and Care Professionals of BC, physiotherapist scope of practice