Treatment of symptomatic para-articular intraosseous cysts by percutaneous injection of bone cement

Calcium Phosphate Cements Combined with Blood as a Promising Tool for the Treatment of Bone Marrow Lesions

The solid phase of a commercial calcium phosphate (Graftys^® HBS) was combined with ovine or human blood stabilized either with sodium citrate or sodium heparin. The presence of blood delayed the setting reaction of the cement by ca. 7-15 h, depending on the nature of the blood and blood stabilizer. This phenomenon was found to be directly related to the particle size of the HBS solid phase, since prolonged grinding of the latter resulted in a shortened setting time (10-30 min). Even though ca. 10 h were necessary for the HBS blood composite to harden, its cohesion right after injection was improved when compared to the HBS reference as well as its injectability. A fibrin-based material was gradually formed in the HBS blood composite to end-up, after ca. 100 h, with a dense 3D organic network present in the intergranular space, thus affecting the microstructure of the composite. Indeed, SEM analyses of polished cross-sections showed areas of low mineral density (over 10-20 µm) spread in the whole volume of the HBS blood composite. Most importantly, when the two cement formulations were injected in the tibial subchondral cancellous bone in a bone marrow lesion ovine model, quantitative SEM analyses showed a highly significant difference between the HBS reference versus its analogue combined with blood. After a 4-month implantation, histological analyses clearly showed that the HBS blood composite underwent high resorption (remaining cement: ca. 13.1 ± 7.3%) and new bone formation (newly formed bone: 41.8 ± 14.7%). This was in sharp contrast with the case of the HBS reference for which a low resorption rate was observed (remaining cement: 79.0 ± 6.9%; newly formed bone: 8.6 ± 4.8%). This study suggested that the particular microstructure, induced by the use of blood as the HBS liquid phase, favored quicker colonization of the implant and acceleration of its replacement by newly formed bone. For this reason, the HBS blood composite might be worth considering as a potentially suitable material for subchondroplasty.

Endoscopic Treatment of Symptomatic Foot and Ankle Bone Cyst with 3D Printing Application

Objective

To study the efficacy of arthroscopy for treating symptomatic bone cysts of the foot and ankle through the follow-up of patients and to further explore the application value of 3D printing technology in this treatment.

Methods

Twenty-one patients with symptomatic bone cysts in the foot and ankle who underwent arthroscopic surgery in our Center from March 2010 to December 2018 were enrolled, including 11 in the experimental group and 10 in the control group. For the control group, C-arm fluoroscopy was used intraoperatively to confirm the positioning of the cysts; for the experimental group, a 3D model of the lesion tissue and the 3D-printed individualized guides were prepared to assist the positioning of the cysts. Debridement of the lesion tissues was conducted under an arthroscope. Regular follow-ups were conducted. The time of establishing arthroscopic approaches and the times of intraoperative fluoroscopy between the two groups were compared. Significance was determined as P < 0.05.

Results

The postoperative pathology of the patients confirmed the diagnosis. No significant perioperative complications were observed in either group, and no recurrence of bone cysts was seen at the last follow-up. The VAS scores and AOFAS scores of the two groups at the last follow-up were significantly improved compared with the preoperative data, but there was no statistical difference between the two groups. All surgeries were performed by the same senior surgeon. The time taken to establish the arthroscopic approaches between the two groups was statistically significant (P < 0.001), and the times of intraoperative fluoroscopy required to establish the approach were also statistically significant (P < 0.001). The intraoperative bleeding between the two groups was statistically significant (P < 0.01). There was 1 case in each group whose postoperative CT showed insufficient bone grafting, but no increase in cavity volume was observed during the follow-up.

Conclusion

With the assistance of the 3D printing technology for treating symptomatic bone cysts of the ankle and foot, the surgeon can design the operation preoperatively and perform the rehearsal, which would make it easier to establish the arthroscopic approach, better understand the anatomy, and make the operation smoother. This trial is registered with http://www.clinicaltrials.govNCT03152916.