When pediatricians evaluate children and adolescents with overweight and obesity, a heightened suspicion for orthopedic co-morbidities can help optimize patients’ current and future health.
The following is guidance on how to recognize and manage common orthopedic co-morbidities, which often are exacerbated by barriers to subspecialty care and increased disease severity.
Slipped capital femoral epiphysis (SCFE)
SCFE is a disease of the proximal femoral (hip) physis (growth plate) affecting children and adolescents. Childhood obesity is strongly associated with SCFE, and higher body mass index increases the risk and reduces the age at disease onset (Perry DC, et al. Pediatrics. 2018;142:e20181067).
If a patient with open growth plates has hip, thigh or knee pain (as pain can be referred), a limp or new onset and/or asymmetric out-toeing, the affected side should be made non-weight bearing. The patient also should be referred urgently to outpatient orthopedics or through the emergency department. If obtaining X-rays prior to referral will not delay evaluation, they can be performed urgently and should include frog leg lateral views.
After surgery, weight management may help reduce the risk of contralateral SCFE, improve patient-reported outcomes and reduce other negative obesity-related sequelae (Escott BG, et al. J Bone Joint Surg Am.2015;97:1929-1934; Griggs CL, et al. Surg Obes Relat Dis. 2019;15:1836-1841; Nasreddine AY, Clin Orthop Relat Res. 2013;471:2137-2144).
Blount’s disease is characterized by bowing deformity at the knees (genu varum) hypothesized to be from an illness of the medial proximal tibia physis of unknown cause. There are two distinct forms: infantile and adolescent (Birch JG. J Am Acad Orthop Surg. 2013;21:408-418).
Physiologic bowing can be seen in infants and toddlers, but correction to a neutral alignment often occurs by age 2 years. Risk factors for infantile Blount’s include early walking age, large stature and/or obesity. Adolescents with Blount’s disease often have obesity (Birch JG. J Am Acad Orthop Surg. 2013;21:408-418).
Patients with bowing that persists beyond age 2 years should be screened for vitamin D deficiency to rule out rickets and referred to pediatric orthopedics on an outpatient basis for imaging (Diab L, Krebs NF. Pediatr Rev. 2018;39:161-179). Blount’s disease often requires surgery and can increase the risk of arthritis in adulthood (Sharma L, et al. JAMA. 2001;286:188-195).
Scoliosis is a coronal (frontal) plane asymmetry of the spine of more than 10 degrees. Adolescents with obesity have a similar prevalence of idiopathic scoliosis as those with normal weight but may have more severe disease (Armstrong S, et al. Pediatrics. 2016;137:e20151766).
In addition, the threshold for referral to orthopedics based on the Adam’s test is different in children with obesity. Historically, scoliometer measurements greater than 7 degrees (corresponding to a 20-degree curve) indicated need for orthopedic referral. However, due to differences in chest wall thickness, referral threshold should be lowered to 5 degrees for patients with obesity (Bunnell WP. Spine. (Phila Pa 1976). 1993;18:1572-1580; Margalit A, et al. J Pediatr Orthop. 2017;37:e255-e260).
Furthermore, obesity has been associated with less successful results with bracing and increased scoliosis surgery complications, so early weight management may be considered (O'Neill PJ, et al. J Bone Joint Surg Am. 2005;87:1069-1074; Hardesty CK, et al. Clin Orthop Relat Res. 2013;471:1230-1235).
Pes planovalgus, genu valgum
Pediatricians frequently encounter pes planovalgus (flat feet) and genu valgum (“knocked knees”). Knowing when to be concerned among those with overweight and obesity is helpful, as many may not need a referral to orthopedics.
Cross-sectional studies show the prevalence of flat feet increases with weight. Pediatricians should look for flat feet that are stiff in that arches do not form when patients stand on their toes. Patients with stiff flat feet or painful flexible flat feet that do not improve with over-the-counter gel inserts, stretching and nonsteroidal anti-inflammatory medications should be referred to orthopedics.
Pediatricians also should look out for genu valgum in children older than 7 years, especially if it worsens over time. Placing clinical photos in the electronic medical record can help document serial exams.
Any concern should prompt referral to orthopedics on an outpatient basis. Timely referral can impact the nature of treatment, as less invasive treatment (guided growth) can be used prior to skeletal maturity.
Obesity is thought to play a role in the etiology of genu valgum that progresses with age. Genu valgum increases the stress on the lateral knee, which may increase the risk of arthritis (Sharma L, et al. JAMA. 2001;286:188-195; Walker JL, et al. J Pediatr Orthop.2019;39:347-352).
If children with overweight or obesity have an acute injury, heightened suspicion for a fracture is warranted. Obesity itself may not increase the risk of fracture and actually may protect against open fractures (Li Y, et al. J Pediatr Orthop. 2020;40:e127-e130; Sabhaney V, et al. J Pediatr. 2014;165:313-318.e1). However, overweight and obesity are associated with increasing rates of foot, ankle, lower leg and knee fractures, particularly among 6- to 11- year olds, as well as more complex and severe patterns of elbow fractures (Fornari ED, et al. Clin Orthop Relat Res. 2013;471:1193-1198; Kessler J, et al. Clin Orthop Relat Res. 2013;471:1199-1207;Seeley MA, et al. J Bone Joint Surg Am. 2014;96:e18).
Despite the complex nature of managing orthopedic co-morbidities of obesity in children and adolescents, these diseases are treatable and can be managed successfully with collaboration between pediatricians and orthopedists.
Dr. Karkenny is a member of the AAP Section on Orthopaedics.