Prediction of femoral head avascular necrosis following femoral neck fracture: “pin-tract sign” of ^99mTc-HDP pinhole bone scan after metallic fixation

Abstract

Objective: To evaluate the predicting value of 99mTc-hydroxydiphosphonate (HDP) pinhole bone scan in development of osteonecrosis of femoral head (ONFH) in patients with femoral neck fracture after cannulated screw fixation. Methods: Pinhole bone scan of patients with metallically fixed femoral neck fracture from 2001 to 2015 were retrospectively reviewed. Initial pinhole bone scan was obtained within 2–3 weeks after surgery. Findings of initial pinhole bone scan were divided in to 4 groups. Group CU included cold defect in affected femoral head, group HU with no cold defect. Group PP with increased uptake along the inserted screws and group PN with no increased uptake along the inserted screws. More than 6 months of follow-up with pinhole bone scan and clinico-radiological evidence for ONFH was reviewed. Results: 72 patients (mean age 54.01 years, male 22, female 50) were included. 19 patients were in group CU, 53 in group HU. 60 patients were in group PP, 12 in group PN. During the follow-up, 13 patients were diagnosed as ONFH. 9 (47.36%) patients in group CU developed ONFH and 4 (7.5%) in group HU. 4 (6.66%) patients in group PP developed ONFH and 9 (75%) in group PN. Conclusions: To predict ONFH of femoral head followed by neck fracture, many imaging techniques with variable results were known. In this study, cold defect in early postoperative pinhole bone scans could predict ONFH, and loss of increased uptake along screw inserted site could be a strong indicative sign of ONFH. Further evaluation with a larger population is necessary.

Methods to predict osteonecrosis of femoral head after femoral neck fracture: a systematic review of the literature

“…Preoperative quantitative indicators included a percentage of photon defect [ 41 ], head-to-head uptake ratio or head-to-acetabulum uptake ratio [ 42 ], and the ratio of radionuclide uptake of the affected fractured femoral head to the healthy contralateral femoral head (F/N) [ 43 , 44 ]. Postoperative quantitative indicators include the mean standardized uptake value of the femoral head (SUV) [ 45 , 46 ]. Park et al [ 41 ] concluded that the percentage of photon defect in the femoral head was a useful index to determine the surgical methods for FNFs, considering hip replacement when the photon defect was greater than 15%, and internal fixation if the photon defect was less than 15%.…”

Safety of surgical hip dislocation in femoral head fracture and dislocation (FHFD) and avascular necrosis risk factor analysis of FHFD: midterm results confirmed by SPECT/CT and MRI

“…Among the fractures classified according to the Pipkin system, type III fractures (i.e., femoral neck fractures with femoral head fractures) have unfavorable clinical and radiologic outcomes [ 25 ]. Simultaneous fractures of the femoral neck and head contribute to difficulty in performing reduction and fixation, and AVN can develop owing to medial femoral circumflex artery injury that occurs with the fracture [ 26 ]. In this study, femoral neck fractures frequently caused complications with two of the three (66.7%) patients with femoral neck fractures developing AVN.…”

Comparison of young femoral neck fractures treated by femoral neck system, multiple cancellous screws and dynamic hip screws: a retrospectively comparison study

“…The most serious complication of femoral neck fracture is avascular necrosis of the femoral head and internal xation failure [21,22], and there are many factors leading to these complication, such as the age of the patient, general health status, combined underlying diseases, injury mechanism, fracture displacement, osteoporosis, etc., and the above factors cannot be controlled by the doctor [23,24]. What can interfere is the operation time, the quality of fracture reduction and the choice of internal xation.…”