CORR Insights®: What is the Accuracy and Reliability of the Peritubercle Lucency Sign on Radiographs for Early Diagnosis of Slipped Capital Femoral Epiphysis Compared With MRI as the Gold Standard?

Where Are We Now?

In this retrospective study, Maranho and colleagues [7] compared an identifiable finding on plain radiographs (the peritubercle lucency sign) to fluid-sensitive MRI sequences in order to identify patients who were in a “preslip” state of slipped capital femoral epiphysis (SCFE). The authors described a high degree of agreement between the presence of the peritubercle lucency sign and an MRI diagnosis of “preslip”. Having a plain radiographic finding that could identify a SCFE before displacement as effectively as MRI would be an important contribution towards less-expensive diagnostic testing of preslip conditions, but several related points deserve consideration.

Social and economic factors have been associated with delays in timely diagnosis and treatment of health problems in children (including SCFE) [1, 3, 11]. Such factors include access to healthcare resources, late diagnosis because of variations in knowledge, delay in referral to specialists, and inconsistent ability of providers to interpret imaging results [3, 6, 11].

Although radiographs are less costly and more widely available than MRI, we still need to test them for their predictability in the setting of clinical pathways or diagnostic algorithms. False-positives leading to unnecessary treatments remain a concern, along with uncertainty regarding the risks and morbidity reduction associated with treatment of patients with preslip or contralateral slip compared to patients with mild or moderate displacement [8, 12].

Where Do We Need To Go?

Late diagnosis and treatment for pediatric conditions are medical errors and should be considered as such. While the current study will help in imaging interpretation, most medical errors are a product of systemic healthcare delivery errors and require an analysis of decision making across the care pathway. We need to go beyond proposing improved education for residents, primary care providers, and nonpediatric orthopaedic surgeons because such solutions have proven to be low-impact interventions for providing sustainable change in serious event reviews [2]. Diagnostic algorithms have also been proposed for specific conditions such as pediatric bone and joint infections [5, 9] and the limping child [10]. No study has assessed the utility of these algorithms in decreasing the incidence of missed diagnosis for specific conditions such as SCFE and an algorithm for diagnosing SCFE has not been proposed. We need to investigate the use of diagnostic algorithms or clinical pathways within the framework of health systems’ local environment to better apply diagnostic interpretative knowledge.

Orthopaedic surgeons should define an acceptable time from onset of symptoms to diagnosis for SCFE, and what skills and tools are needed by providers to make such a diagnosis. By obtaining this information, health systems could develop clinical pathways and diagnostic algorithms to facilitate earlier referral to appropriate clinicians for diagnosis.

How Do We Get There?

A paradigm shift towards localized quality improvement research could move the needle on early detection of SCFE. While quality-improvement tools such as fishbone diagrams, run charts, process maps, and Pareto charts may be unfamiliar to many orthopaedic surgeons, care pathways and team approaches to clinical problems are familiar [4]. Most health systems have used these tools in response to serious event reviews. Orthopaedic surgeons should learn these methods and participate actively in the development, testing, and reporting of the results of interdisciplinary pathways for early diagnosis and treatment. These metrics should be compared to other health systems, and used to drive continued efforts for improvement.