Epiphysiolysis is the separation or slippage of a growth plate, the cartilaginous zone near the end of a growing bone where new bone tissue forms. It can happen suddenly from a fracture, gradually from repetitive stress, or insidiously as a chronic condition tied to body weight and hormonal shifts. The term covers several distinct clinical scenarios, but by far the most consequential is slipped capital femoral epiphysis (SCFE), in which the ball at the top of the thighbone slides off the neck of the femur through the growth plate. SCFE remains the most common adolescent hip disorder, and the way it presents, gets missed, and affects people decades later makes it one of the most underappreciated problems in pediatric orthopedics.
What the Growth Plate Has to Do With It
In children and adolescents, long bones grow at the physis, a layer of cartilage sandwiched between the end of the bone (the epiphysis) and the shaft (the metaphysis). This cartilage is softer and mechanically weaker than bone on either side of it, which makes it a natural fault line. Any force that exceeds what the growth plate can tolerate, whether that force comes all at once from a fall or accumulates over months of weight-bearing, can cause the epiphysis to shift relative to the shaft. That shift is epiphysiolysis. It can be classified by cause (traumatic, stress-related, or idiopathic), by location (hip, wrist, ankle, knee), or by severity, but the underlying event is the same: the growth plate gives way.
SCFE and Why the Hip Is the Epicenter
The proximal femoral physis sits at the junction between the femoral head and neck, and it bears an enormous amount of load. During normal activities like walking and climbing stairs, the physis absorbs shear forces generated by body weight pushing down and the hip joint’s geometry directing those forces at an angle. A finite element analysis found that stress, strain, and displacement at this growth plate all increased with greater body weight, femoral neck retroversion (a backward twist in the anatomy of the upper femur), and a more vertical loading angle at the hip. When an overweight child has both retroversion and that kind of loading geometry, the shear strain across the physis can exceed the failure threshold for cartilage, triggering a slip.1Journal of Pediatric Orthopaedics. Proximal Femoral Physis Shear in Slipped Capital Femoral Epiphysis-A Finite Element Study
This is why SCFE overwhelmingly affects children during the adolescent growth spurt, when body weight outpaces the structural maturation of the growth plate. It occurs most often between ages 10 and 16 and is more common in boys and in children with obesity. But weight alone does not explain every case. In a review of 85 patients who had both an endocrine disorder and SCFE, hypothyroidism accounted for about 40% and growth hormone deficiency for 25%. Children with these hormonal conditions presented at atypical ages, sometimes younger than 10 or older than 16, and the rate of bilateral involvement was strikingly high at 61%.2PubMed. Slipped capital femoral epiphysis associated with endocrine disorders Because of findings like these, screening for hypothyroidism is recommended in patients who present with SCFE at unusual ages or who have short stature.3PubMed. Slipped capital femoral epiphysis and associated hypothyroidism
The Diagnosis That Keeps Getting Missed
One of the most frustrating things about SCFE is how often doctors miss it on the first visit. The classic presentation is a teenager with a limp and groin or hip pain, but many patients don’t present that way. A nationwide cohort study found that three-quarters of children with SCFE had multiple primary care contacts for relevant symptoms before anyone ordered a hip X-ray. The delay was worst for those whose main complaint was knee pain: their median diagnostic delay was 161 days, compared to about 20 days for children who presented with hip pain or a gait abnormality.4Archives of Disease in Childhood. A nationwide cohort study of slipped capital femoral epiphysis
A separate review of 116 children with SCFE found that the diagnosis was initially missed in 29% of cases. The children whose SCFE was missed were significantly less likely to have hip pain and more likely to complain of thigh pain, which sent clinicians looking elsewhere.5Pediatrics. Slipped Capital Femoral Epiphysis Without Hip Pain Leads to Missed Diagnosis The hip can refer pain anywhere from the groin to the knee along the obturator nerve, so a teenager who limps and says their knee hurts may never get their hip examined. This is one of the most widely taught lessons in pediatric orthopedics and yet it continues to happen.
How Imaging Confirms the Slip
The standard first step is a plain X-ray, typically an anteroposterior (AP) view and a frog-lateral view of both hips. Clinicians traditionally use Klein’s line, a line drawn along the upper edge of the femoral neck on the AP view, to check whether it intersects the femoral head. If it doesn’t, something has shifted. The problem is that this classic test is not very sensitive. One study found the traditional Klein’s line identified only about 39% of confirmed slips on the AP view. A modified version that measures the width of the epiphysis extending beyond the line improved sensitivity to about 87%, and the frog-lateral view alone caught all 23 confirmed cases in the same study.6PubMed. Klein line on the anteroposterior radiograph is not a sensitive diagnostic radiologic test for slipped capital femoral epiphysis A separate analysis using the modified approach similarly boosted sensitivity from roughly 40% to 79% on the AP view alone.7PubMed. A modification of Klein’s Line to improve sensitivity of the anterior-posterior radiograph in slipped capital femoral epiphysis
When the X-ray is equivocal or a very early “pre-slip” is suspected, MRI becomes valuable. On T1-weighted images, physeal widening is visible in essentially every case of SCFE, including pre-slips that radiographs miss entirely.8PubMed. Slipped capital femoral epiphysis: a physeal lesion diagnosed by MRI, with radiographic and CT correlation MRI can also detect bone marrow edema adjacent to the physis, which may signal that the contralateral hip is at risk of slipping in the future. In one study of patients who already had SCFE on one side, MRI picked up early signs on the opposite hip with a sensitivity of 80% and specificity of about 93%.9PubMed Central. MRI in idiopathic, stable, slipped capital femoral epiphysis: evaluation of contralateral pre-slip
Stable Versus Unstable Slips
How a slip is classified matters enormously for treatment and prognosis. A stable SCFE means the child can still walk, even if painfully. An unstable SCFE means they cannot bear weight at all, usually because the slip happened suddenly or worsened acutely. Unstable slips carry a much higher risk of avascular necrosis (AVN), the death of bone tissue in the femoral head due to disrupted blood supply. A recent structure called the epiphyseal tubercle plays a key role here: in chronic stable slips, the epiphysis rotates around the tubercle and the blood vessels stay intact, whereas in acute unstable slips, the tubercle displaces and the blood supply is jeopardized.10PubMed Central. Evolving Understanding of and Treatment Approaches to Slipped Capital Femoral Epiphysis
Among unstable hips in one study, half developed AVN, and those with AVN had considerably more displacement of the femoral head.11Journal of Pediatric Orthopaedics. Perfusion Magnetic Resonance Imaging is the Best Way to Predict the Occurrence of Avascular Necrosis in Slipped Capital Femoral Epiphysis A systematic review and meta-analysis pooling unstable SCFE cases found the overall incidence of AVN after surgery was about 23%, with the main risk factors being male sex, a slip angle of 30 degrees or greater, acute onset of symptoms, and closed reduction (manually pushing the femoral head back into position).12PLoS One. Risk factors associated with avascular necrosis following unstable slipped capital femoral epiphysis in pediatric patients Of the modifiable risk factors, the biggest statistical predictor of AVN and chondrolysis (destruction of hip cartilage) was the presence of abnormal periosteal sleeve disruption.13PubMed. The most important risk factors for avascular necrosis and chondrolysis in patients with slipped capital femoral epiphysis
How SCFE Is Treated
For mild-to-moderate stable slips, the standard treatment worldwide is in situ fixation: a single screw is placed across the physis to stabilize the femoral head in its current position and prevent further slipping. The goal is not to push the head back where it belongs but to stop it from going any further while the growth plate fuses. A technique study following patients for at least a year reported no cases of AVN, chondrolysis, or screw-related complications with this approach.14PubMed Central. A Simple Modified Technique for In-Situ Screw Fixation in Slipped Capital Femoral Epiphysis Two screws may be used for unstable or more severe slips, though that scenario opens the door to more complex decisions.
For severe slips, especially unstable ones, surgeons may consider the modified Dunn procedure, an open surgery that carefully detaches the femoral head, preserves its blood supply through the retinacular vessels, corrects the deformity, and then reattaches it. Long-term follow-up of patients who underwent this procedure showed good functional outcomes: average hip scores in the 90s on a 100-point scale, and just a 5% rate of AVN. Only one hip out of 43 showed progression of osteoarthritis over the follow-up period.15PubMed. Patients with severe slipped capital femoral epiphysis treated by the modified Dunn procedure have low rates of avascular necrosis, good outcomes, and little osteoarthritis at long-term follow-up A systematic review comparing the modified Dunn to intentional closed reduction found no significant difference in AVN risk between the two, but the Dunn procedure is generally reserved for the most severe deformities where closed reduction would be inadequate.16PubMed Central. Prevalence of Avascular Necrosis Following Surgical Treatments in Unstable Slipped Capital Femoral Epiphysis (SCFE) That said, osteonecrosis remains a real concern with the Dunn procedure, and recent reviews caution that it should be performed only by experienced surgeons at high-volume centers.
The Question of the Other Hip
When a child shows up with SCFE on one side, the other hip immediately becomes a concern. Given the high bilateral involvement seen in endocrine-related cases and the general bilateral rate, many surgeons consider prophylactic pinning of the unaffected hip. But deciding who actually needs it is surprisingly difficult.
One study found that chronological age was the only reliable predictor: children younger than 13 at the time of their first slip were much more likely to develop a contralateral slip. Using age under 13 as the threshold for recommending prophylactic fixation yielded 88% sensitivity and 51% specificity.17PubMed Central. The contralateral hip in slipped capital femoral epiphysis: Is there an easy-to-use algorithm to support a decision for prophylactic fixation? Attempts to use X-ray measurements of the opposite hip have not panned out well. A study comparing three groups of patients found that radiographic angles alone had no predictive value for determining who would develop a contralateral slip, though an open triradiate cartilage (a growth center in the pelvis that hasn’t yet fused) roughly doubled the likelihood.18Journal of Pediatric Orthopaedics B. Can we still use X-rays to predict contralateral slip in primary unilateral slipped capital femoral epiphysis?
A nationwide survey of pediatric orthopedic surgeons found that their decisions were influenced by body mass index, triradiate cartilage status, patient race, endocrine abnormalities, and various radiographic measurements, but there was no consensus algorithm.19PubMed. Surgeon Preference for Prophylactic Contralateral Fixation in Slipped Capital Femoral Epiphysis (SCFE) Patients This remains one of those areas where clinical judgment does a lot of heavy lifting because the data has not caught up.
SCFE and Femoroacetabular Impingement
Even after successful fixation, SCFE can leave behind a deformed femoral head-neck junction. When the epiphysis slips posteriorly and medially, it creates a bony bump on the front of the femoral neck that can jam against the rim of the hip socket during normal hip movements like bending or twisting. This mechanical conflict is called femoroacetabular impingement (FAI), and it was recognized as a significant pre-arthritic condition in SCFE patients once researchers stopped assuming the hip would simply remodel itself over time. Even mild slips can produce enough of a bump to cause impingement, and the progressive labral damage and cartilage wear that follow are now understood as a pathway to early osteoarthritis.20SICOT-J. Slipped capital femoral epiphysis: a review of management in the hip impingement era
This realization shifted treatment thinking. Rather than assuming that pinning the slip in place and waiting for growth plate closure would be the end of the story, surgeons now evaluate whether the residual deformity will create impingement symptoms down the road. Complex osteotomies and intra-articular procedures performed through a surgical hip dislocation approach have been developed to reshape the proximal femur. These have the potential to prevent decades of wear-related damage but carry their own risks, so the trade-off remains case-by-case.21PubMed Central. Evolving Understanding of and Treatment Approaches to Slipped Capital Femoral Epiphysis
Traumatic Growth Plate Fractures
SCFE is not the only form of epiphysiolysis. In younger children particularly, a direct blow or fall can fracture through the growth plate. These injuries are classified by the Salter-Harris system into five types: type I goes straight through the physis; type II through the physis and the metaphysis; type III through the physis and the epiphysis; type IV through all three zones; and type V, a crush injury to the growth plate itself.22PubMed. Growth plate injuries: Salter-Harris classification Types I and II generally heal well, while types III through V carry higher risks of growth disturbance. Type V is particularly insidious because the initial X-ray may look nearly normal, yet the compression has damaged the growth cells enough to cause premature partial closure of the physis, leading to a limb-length discrepancy or angular deformity as the child grows.
Overuse Epiphysiolysis in Young Athletes
Repetitive stress can damage a growth plate just as effectively as a single traumatic event, given enough time. The classic example is “gymnast’s wrist,” a stress injury to the distal radial physis caused by the enormous axial loads that young gymnasts put through their wrists during tumbling, vaulting, and beam work.23PubMed. Gymnast’s Wrist (Distal Radial Physeal Stress Syndrome) On MRI, the characteristic finding is widening of the growth plate on its palmar side with bone marrow edema in the adjacent bone.24PubMed Central. MRI Diagnosis of Gymnast’s Wrist (Distal Radial Physeal Stress Injury) Unlike acute fractures, these stress injuries tend to creep up gradually: a gymnast may notice wrist soreness during practice that worsens over weeks before anyone orders imaging.
The main concern with chronic physeal stress is premature growth plate closure. If the child is still growing significantly, partial arrest of the distal radial physis can cause the radius to end up shorter than the ulna, altering wrist mechanics and potentially requiring surgery. Treatment usually involves rest from the offending activity, though the duration of rest and the question of when and whether to return to full training are sources of considerable debate among sports medicine physicians.
A Genetic Component
Most cases of SCFE are labeled “idiopathic,” meaning no specific underlying disease is identified. But evidence points to a hereditary element. Genetic conditions associated with SCFE include mutations in the COL2A1 gene (which encodes type II collagen, a key structural protein in cartilage), aromatase deficiency, and Prader-Willi syndrome.25PubMed Central. Internal diseases and molecular mechanisms causing slipped capital femoral epiphysis in children Familial clusters have also been documented in children without any known genetic syndrome. A report of three biologically related sisters, all athletic and none overweight, who each developed SCFE despite having no hormonal imbalances or endocrine abnormalities illustrates that the condition can run in families through mechanisms that are not yet mapped to a specific gene.26PubMed. Three cases of slipped capital femoral epiphysis in one family No genetic marker has been established for routine screening, so for now, family history mostly serves as an added reason for vigilance.
What Happens Decades Later
A large population-based study comparing over 2,500 patients who had SCFE against matched controls followed them well into adulthood and found some striking long-term associations. The risk of obesity was roughly nine times higher in the SCFE group, and the risk of hypothyroidism was about three times higher. All-cause mortality was approximately double that of controls. Depression risk, by contrast, was not meaningfully elevated.27PubMed Central. Fate of patients with slipped capital femoral epiphysis (SCFE) in later life These associations likely reflect a mix of causes: the same metabolic and endocrine factors that predispose children to SCFE also predispose them to obesity and thyroid problems in adulthood, and the physical limitations from hip damage may further reduce activity levels over the lifespan. The mortality finding is sobering and suggests that SCFE should be seen not just as a hip problem that resolves after surgery, but as a flag for lifelong metabolic risk.
For patients who do develop residual hip deformity and symptomatic impingement, arthroscopic treatment of mild-to-moderate deformity has shown promising results. Functional hip scores improved substantially after arthroscopy in one cohort, with the average modified Harris Hip Score rising from about 64 preoperatively to 91 afterward and the sports activity score nearly doubling. These outcomes suggest that even when the initial surgical fixation leaves an imperfect hip shape, there are effective options for addressing the mechanical consequences years later.