Affinos (Kuraray, Japan) is a β-tricalcium phosphate bone substitute with a unidirectional porous structure. This study aimed to investigate its efficacy on the healing process after filling for bone defects. Fifty-six patients who met the inclusion criteria were divided into cohort 1 (n = 30), including bones other than phalanges and metacarpal/tarsal bones, and cohort 2 (n = 26), including phalanges and metacarpal/tarsal bones. Semi-quantified scores for material resorption and trabeculation through the defect were evaluated with radiographs after surgery. In some patients, levels of bone metabolic markers were assessed. The values of resorption and trabeculation increased steadily with time, and trabeculation progressed compared with resorption in both cohorts. In cohort 1, multiple regression analyses showed that the diaphyseal lesion, smaller defect volume, and increased resorption values at 3 months were associated with increased values of resorption 12 months after surgery (R2 = 0.66, p < 0.001). The trabeculation values at 2 months were positively related to the trabeculation values 12 months after surgery (R2 = 0.35, p = 0.002). In cohort 2, the increased resorption values at 2 months and smaller defect volume significantly correlated with the increased resorption values 12 months after surgery (R2 = 0.58, p < 0.001). The ratio from the baseline of pyridinoline cross-linked carboxyterminal telopeptide of type I collagen at 3 months was negatively associated with the trabeculation values 12 months after surgery (R = − 0.791, p = 0.004). Evaluation of radiographic images and bone metabolic markers in the early postoperative period may predict the healing status at 12 months postoperatively in the defects followed by Affinos filling.

Purpose: Osteochondral destruction and high recurrence rate after surgery are major concerns during the treatment course of tenosynovial giant cell tumor. The aims of this study were to elucidate rates of local recurrence and osteochondral destruction, and demographic factors correlated with osteochondral destruction and recurrence rate after surgery. Methods: Eighty surgically treated patients (knee: 49, ankle and foot: 12, hip: 10, others: 9) were included in this study. Factors including age, disease type (diffuse/localized), location, existence of osteochondral destruction were analyzed to be correlated with local recurrence or development/progression of osteochondral destruction. Results: The 5-year local recurrence free survival rate was 71.4 %. Diffuse type (n=59, localized: n=21) (P=0.023) and knee location (P=0.002) were independent risk factors for local recurrence. Diffuse type (P=0. 009) was a significant risk factor, and knee location (P=0. 001) was a negative factor for osteochondral destruction at the initial examination. Progression of osteochondral destruction was observed more often in cases with local recurrence (P=0.040) and findings of osteochondral destruction at the initial examination (P=0.029).Conclusions: Diffuse type is a factor that should be noted for both local recurrence and osteochondral destruction, and local recurrence occurs but osteochondral destruction is less observed for knee location.