CT-based Classification System Has Prognostic Value for Calcaneal Fractures
A long-term follow-up study by Sanders et al demonstrates that their classification system can reliably predict outcomes of displaced, intraarticular calcaneal fractures. It also raises important issues to address with further research.
Richard Yoon, MD, and Philipp Leucht, MD
Sanders, R. Vaupel, Z.M. Erdogan, M. Downes, K. Operative treatment of displaced intraarticular calcaneal fractures: long-term (10-20 years) results in 108 fractures using a prognostic CT classification. J Ortho Trauma. 28(10), October 2014. 551-63.
In 1992, Sanders et al set forth a standard with the advent and use of a prognostic classification system based on computed tomography (CT). The original paper highlighted a systematic fracture reduction protocol with restoration of the posterior facet, followed by definitive fixation of the calcaneal body.
While there have been those who have questioned its usefulness, the classification system has remained a mainstay of clinical practice and operative planning.
This study revisits the original protocol and the prognostic classification system by reporting on the long-term (10 to 20 years) follow-up on these patients for 2 primary reasons:
- To determine if the CT-based classification system still held as a prognostic indicator for outcomes
- To critically evaluate outcomes of the surgical technique, specifically whether the Böhler’s angle collapsed on long-term follow-up
The second objective had particular importance, as the study period focused on a cohort of patients who were fixed without the use of locking plates or bone graft.
During a 10-year period, 639 operative displaced, intraarticular fractures were screened, and 208 met inclusion criteria. A minimum 10 year follow-up was required for inclusion into this study, along with radiographic and CT analysis at final follow-up.
Final measurements and grades included Böhler’s angle, posterior facet reduction (>3mm considered malreduced), and post-traumatic osteoarthritis (OA) assessment via the Kellgren and Lawren (K/L) radiographic scale. Several clinical outcome measures were utilized, including the SF-36, the AOFAS score, the Maryland Foot Score, and the Ankle OA Score. Pain was also rated via the Visual Analog Score (VAS).
A final cohort of 93 patients (108 fractures) was available for follow-up and analysis. Mean follow-up was about 15 years, with a mean age of about 61 years at final follow-up.
Outcomes analysis noted that the authors’ original prognostic classification held true. Overall, all fractures had a 29% failure rate, defined by intractable pain requiring subtalar fusion. However on subgroup analysis, those sustaining Sanders Type III fractures were nearly 7 times more likely to develop stage 4 degenerative changes on radiographs. Furthermore, Type III fractures required fusion at a significantly higher rate than Type II fractures (47% vs. 19%, p=0.002).
Of the remaining patients who did not require a fusion, the clinical outcomes were encouraging, with minimal reported pain and nearly 80% within the population norm of validated outcome measures.
Extrapolating the results, the authors came to several conclusions that they believed true regardless of age, sex, or worker’s compensation status:
- First and foremost, the prognostic value of the CT-based classification holds true, especially for higher-grade injury patterns.
- Second, the use of bone grafting and locking plates is probably not necessary, as this large cohort was fixed without each and remained anatomically reduced after long-term follow-up.
- Finally, while anatomic reduction remains the mainstay in achieving desired outcomes, the loss of cartilage at the time of injury leads to degeneration, pain, and fusion, regardless of reduction.
Displaced intraarticular calcaneus fractures remain a challenge to treat. In the past, several methods and techniques of reconstruction have been reported, with varied results.
This long-term outcomes study by Sanders et al offers important information that is not typically available in the trauma literature, where long-term fracture follow-up on fixation failure and clinical outcomes is rare. Longitudinal studies like this one, however, are essential to truly address the effects of reconstruction long after the patient has healed.
With regard to displaced, intraarticular calcaneus fractures, the CT-based classification system remains one of the most reliably prognostic classification systems, supported even now with long-term follow-up. The results from this follow-up publication add valuable information to the literature and present interesting questions that can be addressed with further research.
With higher-grade injuries (Type III), authors report a nearly 7 times higher risk of developing post-traumatic OA, and a 4 times higher risk of requiring a fusion. This begs the question: Should fusions be done acutely? Perhaps, for a select population of patients, an acute subtalar fusion may the answer to an earlier, pain-free recovery. While a few studies have been reported over the last year, a definitive, large-scale multicenter trial is needed.
Finally, with the advent of locking technology and the advancements of bone substitutes, utilizing a more rigid construct has arguably become the norm. However, according to the results of this study, it may not be necessary. Further research must be done to identify the specific characteristics that might require locking plate technology and bone graft, and those that do not.
Long-term longitudinal outcomes studies remain an important part of the orthopaedic literature, and this study sheds an interesting light on a difficult-to-treat fracture. With these new results, additional research may lead to acute fusion and earlier pain-free activity. In addition, for fractures that are fixed, a cheaper construct may be all that is necessary to obtain optimal long-term results.
Richard S. Yoon, MD, is Executive Chief Resident in the Department of Orthopaedic Surgery and Philipp Leucht, MD, is an Assistant Professor of Orthopaedic Surgery and Cell Biology at NYU Langone Medical Center – Hospital for Joint Diseases, New York, New York.