Clinical Orthopaedics and Related Research®

, Volume 472, Issue 7, pp 2287–2289

CORR Insights®: Hospital for Special Surgery Pediatric Functional Activity Brief Scale Predicts Physical Fitness Testing Performance


    • Department of Orthopaedic ResearchUPMC Hamot Medical Center
CORR Insights

DOI: 10.1007/s11999-014-3582-1

Cite this article as:
Cooney, T.E. Clin Orthop Relat Res (2014) 472: 2287. doi:10.1007/s11999-014-3582-1

Where Are We Now?

That obesity remains a national health concern is not a new revelation. That it can lead to morbid conditions such as diabetes, cardiovascular disease, and arthritis is, likewise, well known. What is particularly troublesome is the estimated number of children and adolescents with early onset obesity. Presently, 17% of all children and adolescents in the United States are considered obese, according to Weiss and colleagues [17]. Severe obesity estimates range from 4% to 6% [7].

There are several clinical abnormalities that can accompany childhood obesity, which are likely antecedents to fulminant cardiovascular disease and diabetes. These include high triglyceride levels, low high-density lipoprotein to low-density lipoprotein ratio, high blood pressure, and insulin resistance. Along with a large waist circumference, these clinical and physical findings are the hallmark of so-called metabolic syndrome in adults. Given transient insulin resistance during adolescence and variability in the serum lipid profile with age, there is no rigorous definition of pediatric metabolic syndrome [17].

Apart from pathologies and surgical complications related to cardiovascular and endocrinological realms, childhood obesity has been linked to Blount’s disease, genu valgum, slipped capital femoral epiphysis, and complications with closed fracture reduction [6]. Obesity poses significant risks of postoperative complications following orthopaedic surgical procedures in adulthood. Additionally, several studies of adult patients suggest diminished bone mineral density [13, 18], although this is certainly an inconsistent finding in the literature [1, 2].

Following up on their initial validation study [3], Fabricant et al. described the use of the Hospital for Special Surgery Pediatric Functional Activity Brief Scale (HSS Pedi-FABS) in terms of its relevance to measures of strength and endurance in a sample of more than 150 adolescents from a single center. Fitness assessments were adopted from a software program currently in use in select schools and areas nationwide. Their data found that the HSS Pedi-FABS is moderately correlated to measures of aerobic fitness with good sensitivity and modest specificity. Additionally, the authors utilized receiver operating characteristics to attempt to threshold a value consistent with low VO2-max capacity, which may indirectly serve as a proxy characteristic for pediatric metabolic syndrome.

Where Do We Need To Go?

Postoperative surgical complications in children and adolescents remain a vexing problem, including respiratory dysfunction [5], deep vein thrombosis, decubitus ulcers [11], and surgical site infection [9]. Neuropathy due to loss of small myelinated axons has been linked to obesity [14]. In a rodent model of metabolic syndrome, low aerobic-capacity rats exhibited persistent postoperative learning/memory deficits following anesthesia [4]. Allied with the notion that fitness level and BMI are related, several studies have shown that preoperative fitness level exerts an impact on postoperative outcomes [8, 10, 15].

While Fabricant and colleagues have noted study limitations, I would pose an additional one. As in all branches of science, results need to be corroborated. A study based on a single center is not sufficiently diverse in population to adequately establish conclusive metrics like sensitivity and specificity. This is best exemplified by a comment by Sovio et al. [16], as they noted that a diagnostic study that touted an area under the curve of 0.78 for predicting coronary lesions and 0.84 for aortic lesions in children at-risk failed to be replicated. The Pedi-FABS tool needs to be implemented at other sites and most especially across a wide range of children with diverse demographics, medical history, and BMI. This is especially relevant to the use of this tool to screen children for low aerobic capacity and, by inference, those at-risk for metabolic syndrome.

How Do We Get There?

Certainly, identifying children with substandard fitness levels, especially if it mirrors metabolic syndrome, would prove beneficial to the clinicians and patients alike.

Clinical observation has been touted as an effective means to screen children for metabolic syndrome. Santoro et al. [12] advocate assessing waist-to-height ratio, evidence of skin fold pigmentation (Ancanthosis nigericans), and a family history positive for Type II diabetes mellitus [12]. Making anthropomorphic measurements in the obese population, however, is fraught with difficulty in identifying skeletal anatomic landmarks. Having a functional levels of fitness assessment could offer a valuable complement to clinical observations.

The HSS-Pedi-FABS provides a useful, concise, screening tool to assess aerobic fitness in children. Its ability to be implemented in the clinical setting will provide clinicians with a first-pass fitness assessment of their patients. Along with clinical observation and patient history, this assessment adds to the clinical armamentarium and ultimately may help to identify children with substandard levels of fitness and at-risk for metabolic syndrome.

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© The Association of Bone and Joint Surgeons® 2014