[Technique of implantation of a cementless press-fit cup in revisions with severe bone defects]

Abstract

Objective: Revision of loose cups of total hip arthroplasties. Implantation and solid fixation of a cementless press-fit cup to restore painless joint function.

Indications: Loose cups of total hip arthroplasties. Reimplantation of a prosthetic cup after removal of an infected total hip arthroplasty.

Contraindications: Bone defects of the acetabulum precluding a press-fit fixation (at least three-surface fixation) of the cup. Persistent infection.

Surgical technique: Exposure of the acetabulum using a standard approach. Removal of the loose cup. Cleaning of the ground with a spoon. Reaming of a new, deeper center of rotation in the acetabulum using a small reamer. Stepwise reaming of the acetabulum using increasing reamer sizes without pressure until sufficient bone contact at the rim is reached (at least three-surface fixation). Hammering in of a thin-walled cementless press-fit cup (e.g., AllofitStrade mark) of the next size as compared to the reamer chosen last to reach a 4-mm press-fit fixation. Additional screwing in of two to three cancellous screws into the os ilium.

Postoperative management: Thrombosis prophylaxis, physiotherapy, gait training with partial loading of the limb at 10 kg for a period of 6 weeks. Then increased loading by 10 kg per week.

Results: 52 cup exchanges using an AllofitStrade mark cup were clinically and radiologically analyzed over an average period of 35.8 +/- 8.8 months (26-53 months). The Harris Hip Score increased from a preoperative value of 46.4 to 87.3 points 2 years postoperatively. Two cups showed migration and one hip dislocated. Loosening has not been observed so far.