[Periprosthetic Femoral Fractures after Total Hip Replacement: Our Results and Treatment Complications].

PURPOSE OF THE STUDY The study consists of a retroactive evaluation of results of surgical treatment in patients with periprosthetic femoral fracture after total hip replacement and a comparison with results reported in the literature. MATERIAL AND METHODS In the period from 2003 to 2013, a total of 83 patients with periprosthetic femoral fracture after total hip replacement were treated at our clinic, namely 69 women and 14 men. The mean age in the cohort was 74 years (range 47-87). The Vancouver classification was used to grade the fractures. The cohort included 31 patients with type B1 fracture, 25 patients with type B2 fracture, 8 patients with type B3 fracture, and 19 patients with type C fracture. Altogether 80 patients underwent a surgery, 3 patients with non-displaced type B1 fracture were treated conservatively. The mechanism of injury was a simple fall in 75 % of primary endoprostheses and in 56% of revision endoprostheses. The average time to fracture was 7.6 years in primary implant and 3.6 years in revision endoprosthesis. In fractures with a well-fixed stem (type B1 and C) plate osteosynthesis was used. In case of a comminution zone, osteosynthesis was followed by spongioplasty. In patients with a loose stem (type B2 and B3), the fracture was treated with a revision uncemented stem. In two cases a combination of a revision stem and a massive corticocancellous bone graft was used. The evaluation was performed using the Harris Hip Score and the minimum follow-up from the surgery was 3 years. RESULTS In the group of patients with type B1 fracture, 28 patients were treated surgically. An excellent result was achieved in 22 patients (84%), in 4 patients (16%) the result was very good. The remaining 2 patients failed to meet the requirement of the minimum follow-up of 3 years. In the group of patients with type B2 fractures, composed of 25 patients, the femoral component was replaced with a revision uncemented stem with cerclage wires or titanium tapes or cables. Osseointegration of the stem was recorded in 24 patients, one female patient died 4 months after the surgery. An excellent result was achieved in 16 patients (64%), a very good result in 4 patients (16%). The remaining 5 patients (20%) failed to meet the minimum follow-up of 3 years. In 8 patients with type B3 trauma, the reimplant of a revision stem was supplemented by spongioplasty, in 2 cases by solid corticocancellous bone grafts with cerclage. In this group osseointegration occurred in all the cases within 6-9 months. The follow-up was affected by the older age of patients and 6 patients died during the follow-up period. The requirement of a follow-up longer than 3 years was met in 2 patients (25%) only and the result was considered very good. In the group of 19 patients with type C fracture, plate osteosynthesis was performed, which was in 12 cases complemented with spongioplasty. Healing occurred within 6 months in 13 patients (72%), within 9 months in 3 patients (17%) and in 2 patients (11%) reoperation was carried out due to fixation failure. One female patient died 16 days after the surgery. An excellent result was achieved in 15 patients (83%), in the remaining three patients the follow-up was shorter than three years due to their death. DISCUSSION Periprosthetic femoral fractures after total hip replacement is a rare but feared complication. Its incidence ranges from 0.1 to 4%. It occurs most frequently 7 to 8 years after the primary implant and 3 to 4 years after the revision of endoprosthesis implantation. The main risk factor is the loosening of stem of endoprosthesis. Another risk factor is osteoporosis. Age, sex and obesity do not constitute significant risk factors. Stem stability and presence of bone defects are the main criteria in favour of surgical treatment. If the stem remains well fixed, the osteosynthesis is opted for, whereas if the stem is loose, its replacement has to be performed. The management of bone defects is an integral part of femoral reconstruction and restoration of endoprosthesis stability. CONCLUSIONS Surgical treatment of periprosthetic fractures, thanks to the introduction of new implants for osteosynthesis and development of new stems for revision endoprostheses, helps achieve ever better results. Of major importance for choosing the treatment method is correct classification of fracture and stem stability. Poor bone quality is a common feature, therefore a perfect mechanical fixation is necessary. The long-term results are affected primarily by the patient s age. Key words: periprosthetic femoral fractures, surgical treatment, results, complications.