ABSTRACT
OBJECTIVE: To investigate the risk factors, management and prognosis of femoral neck fracture post total knee arthroplasty (TKA). METHODS: From January 2003 to August 2009, 45 cases of femoral neck fracture post TKA were treated. There were 8 males and 37 females with an age range of 56 - 81 years old. Among them, there were ipsilateral (n = 36) and contralateral (n = 9) femoral neck fractures. Due to the fracture site and type, the treatment plans were formulated. And a follow-up was conducted to record the Harris hip score and complications. RESULTS: The incidence of femoral neck fracture following TKA and osteoporosis had a linear correlation. And the fracture rate increased with the aggravation of osteoporosis. The stability of ipsilateral fracture group was lower than those of contralateral fracture and no fracture groups. Except for 4 mortality cases, 41 patients were followed up for 2 to 7 years with an average period of 3.6 years. There were 12 patients in the cannulated screw fixation group. The outcomes were fracture healing (n = 5) and femoral head necrosis (n = 7). Twenty-five cases underwent femoral head replacement. And 3 died and second fracture occurred in 3 cases. Eight cases underwent total hip arthroplasty. And 1 died and there was 1 case of second fracture. The Harris scores of the cannulated screw fixation group was significantly lower than the hip replacement groups (q test, P < 0.05). COMPLICATIONS: After internal fixation, 7 cases suffered femoral head necrosis and underwent femoral head replacement. And secondary fractures after hip replacement occurred in 4 cases and they were treated by plate and cable or LISS (less invasive stabilization system) system. CONCLUSION: Femoral neck fracture following TKA is usually caused by a low-energy injury. Osteoporosis is one of its high-risk factors. Knee instability is associated with ipsilateral femoral neck fracture. Clinically it can be treated by internal fixation or hip arthroplasty. And internal fixation of femoral neck fracture frequently induces femoral head necrosis. And femoral head replacement is applicable.
