Nickel-titanium shape memory alloy embracing fixator benefits the determination of the implantation angle of prosthesis stem in tumor-type artificial joint replacement

Am J Transl Res. 2022 Jul 15;14(7):4698-4708. eCollection 2022.

Abstract

Background: Hip tumors often require tumor-type artificial joint replacement. The selection of the prosthesis stem (hip tumor prosthesis stem) implantation angle during the operation is important to prevent the complication of postoperative prosthesis dislocation. The aim of this study was to evaluate the role of a nickel-titanium (Ni-Ti) shape memory alloy embracing fixator in determination of the implantation angle of a hip tumor prosthesis stem and analyze its efficacy.

Methods: 36 patients with proximal femur tumor were treated with extended tumor resection and prosthetic replacement. 14 patients received prosthetic replacements with the embracing fixators fixing between the junction of the prosthesis stem and the femur temporarily, while the other 22 patients received the same replacements but without the fixators. The two groups were compared regarding occurrence of complications, limb function, and active hip range of motion (ROM).

Results: There was no case of hip dislocation in the group that received prosthetic replacements with the use of embracing fixators. Occurrence of deep infection had no difference between the two groups. However, better limb function and higher active (ROM) on abduction or flexion were observed in the group using embracing fixators.

Conclusion: Ni-Ti shape memory alloy embracing fixator plays a key role in assisting the accurate implantation angle of the prosthesis stem in prosthetic replacement. The prosthesis stem can be adjusted to the optimal angle with the help of the embracing fixator. Patients have a lower risk of dislocation, better limb function, and higher active hip ROM.

Keywords: Ni-Ti shape memory alloy; hip tumor prosthesis stem; implantation angle.