Michael Yam1, Benjamin Joseph Kang2, Anuj Chawla3, Wei Zhang3, Law Gin Way4, Rex Premchand Antony Xavier5, Derek Howard Park5, N E M Yeo6, T S Howe6, E B K Kwek7. 1. Tan Tock Seng Hospital, Singapore, Singapore. Michael.yam@mohh.com.sg. 2. Singapore General Hospital, Singapore, Singapore. 3. , Singapore, Singapore. 4. Tan Tock Seng Hospital, Singapore, Singapore. 5. KTPH, Singapore, Singapore. 6. Department of Orthopaedic Surgery, Singapore General Hospital, Singapore, Singapore. 7. Department of Orthopaedic Surgery, Woodlands Health Campus, Singapore, Singapore.
Abstract
OBJECTIVES: Proximal femoral nail antirotation (PFNA) cut-in is a unique phenomenon seen in pertrochanteric hip fractures treated with the PFNA. Cut-in refers to the superomedial migration of the proximal femoral blade into the femoral head and hip joint. We recognize that cut-in is a completely separate entity from the well-described cut-out failure. This study assesses relevant radiological and patient risks factors for cut-in. DESIGN: Retrospective multicenter study looking at patients with pertrochanteric hip fractures managed with the Synthes PFNA SETTING: Four tertiary hospitals over 7 years. PATIENTS: Patients with cut-ins were identified. OUTCOME MEASUREMENT: The radiological appearance of this mode of failure was assessed and compared to cut-outs. Patient demographics, fracture configuration, time to implant failure (cut-in), bone mineral density, tip-apex distance, neck-shaft angle and position of the tip of the helical blade in the femoral head were collected. RESULTS: There was a total of 1027 patients across 4 institutions with 23 patients with cut-in. Average neck-shaft angle was 133 degrees. 16 out of 19 patients had severe osteoporosis with BMD < - 2.5. 14 of 23 patients had poor placement of the blade. 13 of 23 had a tip-apex distance of more than 20 mm. CONCLUSION: We propose a standardized nomenclature of "cut-in" for the phenomenon of superomedial migration of the proximal femoral blade. An anatomical neck-shaft reduction, accurate blade placement and increased surveillance for patients with severe osteoporosis are required to reduce the incidence and morbidity of cut-in.
OBJECTIVES: Proximal femoral nail antirotation (PFNA) cut-in is a unique phenomenon seen in pertrochanteric hip fractures treated with the PFNA. Cut-in refers to the superomedial migration of the proximal femoral blade into the femoral head and hip joint. We recognize that cut-in is a completely separate entity from the well-described cut-out failure. This study assesses relevant radiological and patient risks factors for cut-in. DESIGN: Retrospective multicenter study looking at patients with pertrochanteric hip fractures managed with the Synthes PFNA SETTING: Four tertiary hospitals over 7 years. PATIENTS: Patients with cut-ins were identified. OUTCOME MEASUREMENT: The radiological appearance of this mode of failure was assessed and compared to cut-outs. Patient demographics, fracture configuration, time to implant failure (cut-in), bone mineral density, tip-apex distance, neck-shaft angle and position of the tip of the helical blade in the femoral head were collected. RESULTS: There was a total of 1027 patients across 4 institutions with 23 patients with cut-in. Average neck-shaft angle was 133 degrees. 16 out of 19 patients had severe osteoporosis with BMD < - 2.5. 14 of 23 patients had poor placement of the blade. 13 of 23 had a tip-apex distance of more than 20 mm. CONCLUSION: We propose a standardized nomenclature of "cut-in" for the phenomenon of superomedial migration of the proximal femoral blade. An anatomical neck-shaft reduction, accurate blade placement and increased surveillance for patients with severe osteoporosis are required to reduce the incidence and morbidity of cut-in.