Risk prediction and surgical decision-making for pathological fractures in phalangeal enchondroma: validation of the 0.51 threshold and outcome comparison of prophylactic intervention in 65 patients.

BACKGROUND

Enchondroma is the most common benign bone tumor of the hand, predominantly affecting the phalanges and metacarpals, and is frequently complicated by pathological fractures. Although previous studies have explored risk factors based on tumor size, a precise quantitative cut-off value remains undefined. Furthermore, quantitative research regarding the impact of “delayed treatment” on long-term functional outcomes is lacking. This study aims to establish a risk threshold for pathological fractures in phalangeal enchondroma and to provide an evidence-based rationale for optimizing surgical decision-making by comparing the clinical outcomes of prophylactic surgery versus post-fracture management.

METHODS

We retrospectively analyzed the clinical data of 65 patients with phalangeal enchondroma treated surgically at our institution between 2017 and 2025. Patients were categorized into a Fracture Group (n = 35) and a Non-fracture Group (n = 30) based on the presence of a complete preoperative fracture. The tumor-to-phalanx length ratio was measured using the Picture Archiving and Communication System (PACS), and the degree of cortical thinning was assessed according to the Takedani classification. Multivariate logistic regression analysis was employed to identify independent risk factors, and Receiver Operating Characteristic (ROC) curve analysis was used to determine the optimal predictive cut-off value. Primary outcome measures included postoperative bone healing time, Musculoskeletal Tumor Society (MSTS) functional scores, and complication rates.

RESULTS

There were no statistically significant differences in baseline characteristics, such as age and sex, between the two groups (P > 0.05). ROC curve analysis indicated that the optimal tumor-to-phalanx length ratio cut-off value for predicting pathological fracture was 0.51 (AUC = 0.64). Multivariate analysis demonstrated a strong trend suggesting that a higher ratio is associated with increased fracture risk (OR = 8.81), although statistical significance was likely limited by sample size. Regarding clinical outcomes, the Non-fracture Group (prophylactic surgery) demonstrated significantly shorter bone healing times compared to the Fracture Group (9.7 weeks vs. 10.9 weeks, P = 0.006), significantly superior MSTS functional scores (29.3 vs. 25.1, P < 0.001), and a significantly lower incidence of complications (P = 0.011).

CONCLUSION

A tumor-to-phalanx length ratio > 0.51 represents a high-risk threshold for pathological fracture in phalangeal enchondroma. Compared to post-fracture reconstructive surgery, prophylactic curettage and bone grafting for high-risk patients significantly promote bone healing and improve hand function. We recommend early intervention for patients exceeding this threshold to prevent the pathological progression from occult microfracture to complete fracture, and suggest adopting this ratio as a critical metric for guiding clinical decision-making.