Sequential scintimetry after femoral neck fracture. Methodologic aspects and prediction of healing complications

A Scintimetric Study of Colles' Fracture

In order to study whether bone cement (methylmethacrylate) inserted in the medullary cavity of redisplaced Colles' fractures to fill the dorsal defect arising after repeat reduction is an obstacle to bony union, the course of healing was monitored by scintimetry in fractures thus treated (n=10), in fractures treated by external fixation (n= 10), and in undisplaced fractures immobilized in a plaster cast. No differences emerged between the three groups. It is therefore assumed that the insertion of bone cement does not disturb the healing process.

Early Roentgenological Grading of Femoral Shortening is Correlated to the Late Outcome after Femoral Neck Fractures

Using orthoradiography, the distance between the centre of the femoral head and the intercondylar notch was assessed at regular intervals in 144 patients who were followed for a 2-year period after osteosynthesis of a femoral neck fracture. Late complications, such as segmental collapse and non-union, occurred in 27% of the patients. The degree of femoral shortening was significantly correlated to the incidence of late complications. At 1 month, femoral shortening of more than 5 mm was observed in 85% of patients who developed late complications, and in only 5% of patients without such complications. Thus, the observation of a shortening of more than 5 mm predicted a greater than 6-fold increase of the incidence of late complications. The prognostic accuracy of this observation 1 month after treatment was 92%.

Low Field Magnetic Resonance Imaging of Femoral Neck Fractures

Fourteen patients with cervical hip fractures were treated with internal fixation using titanium screws. The femoral head vitality was evaluated with 99Tcm-MDP scintigraphy and scintimetry within 2 weeks postoperatively and by serial low field magnetic resonance imaging (MR). Two patients with reduced radionuclide uptake (femoral head ratio <1.0) developed radiographic signs of femoral head necrosis. MR disclosed the definite area of the necrosis at 2 and 12 months after fracture, respectively. In three of the patients with a high scintimetric uptake (femoral head ratio ≥1.0), MR revealed a focal decrease of the signal intensity in the femoral head or neck at 2, 3 and 7 months after fracture, respectively. The radiographs in one of these patients were normal at 7 months after fracture. The second one showed signs of necrosis at 16 months and the last one developed delayed/non-union. With a non-ferromagnetic osteosynthesis the healing course after femoral neck fracture can be studied with low field MR equipment without disturbing artifacts. The time period between ischaemia and definite abnormalities on MR may embrace several months.

Sequential scintigraphy and orthoradiographic measurement of femoral shortening after femoral neck fracture

The objective of the study was to assess scintigraphic patterns and femoral shortening after femoral neck fracture in order to select predictive parameters for late complications. Eighty-eight patients with osteosynthesized femoral neck fractures were followed for 2 years with regular scintigraphic evaluations and orthoradiographic measurements of femoral length shortening. Four different patient categories were identified with regard to the late outcome two different groups with uneventful healing and two different groups with late complications. Accordingly, a high scintigraphic uptake at 1 month may either point to an uneventful healing if combined with minor femoral shortening or indicate failure if combined with a high degree of femoral shortening. In contrast, low scintigraphic uptake may either reflect primary fracture healing if accompanied by minor femoral shortening or predict failure if a high degree of femoral shortening is present. Compared with using scintigraphy alone, combined scintigraphic evaluation and assessment of femoral shortening increased the accuracy for prediction of late failures from 80% to 93%. Early scintigraphic patterns after osteosynthesis of femoral neck fractures have to be validated with care. Radiographic assessment of femoral shortening, which is less invasive, gives better prognostic accuracy and should therefore be preferred for this purpose.

Prediction of fixation failure in femoral neck fractures. Comminution and avascularity studied in 40 patients

We performed 99m-Tc diphosphonate scintimetries in 40-elderly patients who had undergone screw fixation for a recent subcapital femoral fracture and analyzed their preoperative radiographs. The data were subjected to a logistic regression analysis. Both comminution of the calcar femorale and reduced scintimetric uptake were predictive for failure of the osteosynthesis during the first year. Fracture comminution was more predictive for early failures during 3 months and scintimetry for the later failures.