Incomplete resection increases the risk of local recurrence and negatively affects functional outcome in patients with tenosynovial giant cell tumor of the hindfoot. 
Diffuse tenosynovial giant cell tumors (TGCT) are more likely to occur in the hindfoot and tend to recur after surgical excision.  We performed a pooled analysis of hindfoot TGCT cases to identify factors associated with local recurrence and functional outcomes.  We retrospectively reviewed medical records of 33 patients diagnosed with TGCT (15, localized cases; 18 diffused cases) of the hindfoot between 1998 and 2017.  Median follow-up was 32 months.  Multivariable Cox proportional hazards regression analysis was conducted to estimate the hazard ratios for risk factors for local failure.  Generalized linear regression models were used to assess whether resection status, tumor size, tumor type or bone involvement correlated with the Musculoskeletal Tumor Society (MSTS) score.  Local failure was reported in 30% (10/33) patients.  Multivariable analysis showed that macroscopically incomplete resection was the only independent prognostic factor for poor local failure-free survival (P=.001).  Incomplete resection significantly decreased MSTS score and negatively affected functional outcome (P=.047).  Incomplete resection increases the risk of local recurrence and negatively affects functional outcome in patients with TGCT of the hindfoot.