Uncemented femoral revision arthroplasty using the modular revision prosthesis MRP-TITAN revision stem |
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Authors: | T Mumme R Müller-Rath S Andereya D C Wirtz |
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Institution: | 1. Orthop?dische Klinik, Universit?tsklinikum Aachen, 30, Pauwelsstra?e, D-52074, Aachen, Germany
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Abstract: | Objective Restoration of a painless hip joint capable of bearing weight by uncemented implantation of a rotationally stable, modular
revision stem anchored in the diaphysis.
Indications Prosthetic stem loosening with osteolytic bone defects (defect classification types I–III according to Paprosky), material
failure with broken prosthesis, sub-and/or periprosthetic femoral fractures, and tumors.
Contraindication Extensive osteolysis preventing diaphyseal anchorage of the prosthetic stem.
Surgical technique Transgluteal approach to the hip joint. Removal of the loose prosthetic stem and, if cemented, the bone cement as well. Excision
of intramedullary granulation tissue. Reaming of the medullary cavity with flexible reaming shafts and formfit, uncemented
implantation of the star-shaped modular revision stem with diaphyseal press-fit. If there is extensive loss of metaphyseal
bone stock, augmentation with autogenous-allogenic bone should be performed.
Postoperative management Mobilization on two underarm crutches from the 1st postoperative day. Removal of the Redon drains after 48 hours. Partial
loading with 20 kg for 6 weeks postoperatively. If plain radiographs show unchanged seating of the prosthesis after 6 weeks,
loading can be increased by 10 kg per week until full weight bearing is achieved; thrombosis prophylaxis is continued throughout.
Radiologic checkups will be done after 3, 6, and 12 months. After that, the patient should be checked annually.
Results Forty-five patients (N = 48 prostheses) with an average age of 67.2 years (min/max: 42.4–87.4 years) were investigated. The average implantation
time of the Modular revision prosthesis MRP-TITAN revision stem was 4.7 years (min/max: 1.0–9.0 years). The Harris hip score
for Paprosky bone defect types I–III had increased from 25.6 preoperatively to 71.4 postoperatively at the time of the final
follow-up (p
3 0.05). Extensively defective bone was diagnosed preoperatively in 32 patients (1Paprosky IIB). Plain radiographs showed stable anchorage without migration in 44 patients. In one case, the stem (implantation
time 2.36 years) was replaced due to increasing axial subsidence (15 mm). Good integration of bone graft with subsequent defect regeneration was seen in all patients with bone trans-plant (N = 30). Postoperative dislocation occurred in six patients and required closed reduction in four cases. Open reduction was
performed in two patients, whereby the external rotation angle of the prosthetic neck was corrected without dismantling the
distally anchored prosthetic stem components. The mechanical failure rate over the follow-up period of 9 years was 1 out of
the 48 prospectively investigated prostheses. The rate of survival according to Kaplan-Meier was 97%. |
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Keywords: | Femoral revision arthroplasty Uncemented diaphyseal anchorage Modular revision stem |
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