HAC COATED BIPOLAR HEMIARTHROPLASTY FOR FRACTURE NECK OF FEMUR – ASSOCIATION OF PROSTHESIS SIZE WITH INTRAOPERATIVE METAPHYSEAL FRACTURES

Abstract

Introduction: We studied the possible causes of intraoperative metaphyseal fractures in elderly patients with displaced intracapsular fracture neck of femur treated with an HAC coated bipolar hemiarthroplasty and their effect on patient morbidity.

Methods: 326 patients with 337 displaced intracapsular fractures admitted from November, 2001, to November, 2005 were included. They underwent Furlong bipolar hemiarthroplasty marketed by Joint Replacement Instrumentation Ltd (JRI). The operations were performed by employing a similar technique and anterolateral approach. Postoperative management was same.

Results: Thirty five (10.25%) patients sustained an intraoperative metaphyseal fracture. We found a strong correlation between the incidences of metaphyseal fracture and stem size. Size 9 stem was used in 80 patients without any fracture. Stem size 10 was used in 159 patients and was associated with metaphyseal fractures in 14 patients (8.80%); size 12 stem was used in 98 patients with 21 metaphyseal fractures (21.42%). Vancouver type AL fractures were 26 and 9 type AG. The fracture was found to be unstable and fixation was undertaken in 7 patients. The mean hospital stay for the patients without metaphyseal fracture was 24 days (range 2–83) in comparison to 30 days (range 17–96) for patients with fractures.

Thirty one patients presented from 3–18 months after operation with hip related problems, 17 had thigh pain, 10 periprosthetic fractures but 8 of these 27 had history of intra-operative metaphyseal fractures. Four patients had revision surgery, one each for acetabular erosion and sinking of prosthesis due to old metaphyseal fracture, two had Girdlestone arthroplasty due to deep wound infection.

Conclusion: We conclude that a size 12 stem was associated with high complications rate because there is a big jump for the elderly patients from size 10 to 12 due to the non-availability of size 11 stem in this system. We observed the effect on patient morbidity due to metaphyseal fractures.