Outcomes of immediate full weight bearing protocol for incomplete intertrochanteric occult hip fractures

Occult hip fractures are femoral neck fractures diagnosed by MRI or CT scan following negative plain radiographs. Incomplete intertrochanteric occult hip fractures (IIOHFs) do not involve the medial cortex. These fractures can be isolated but can also occur in the presence of greater trochanter (GT) fractures. Many authors recommend further imaging to exclude IIOHFs in cases where a GT fracture is present on plain radiograph, in order to evaluate the intertrochanteric region fracture extension. There is no consensus on the optimal treatment for IIOHFs, with approaches ranging from surgical fixation to full weight bearing. At our institution a protocol of immediate full weight bearing for patients diagnosed with IIOHFs was implemented. This study retrospectively evaluates the outcomes of this treatment protocol.

The medical records of patients who underwent MRI for suspected occult hip fractures were retrospectively analyzed. Inclusion criteria included: (1) patients with no findings on plain radiographs who were diagnosed by MRI with intertrochanteric fractures not involving the medial cortex, and (2) patients with isolated GT fractures diagnosed by plain radiographs and fracture extension greater than one-third of the intertrochanteric width seen on MRI. Data regarding initial hospitalization, diagnostic timing and findings, and follow-up outcomes were collected.

Of 196 MRI scans performed during the study period, 45 patients met the inclusion criteria. None of these patients experienced secondary displacement of the fracture despite immediate full weight bearing. The average age was 81.1 years, and 21(10.7%) patients were male. The mean time from admission to MRI was 30 h, and the average length of hospitalization was 6.3 days. The 45 intertrochanteric fractures that were included in this study include nine isolated incomplete intertrochanteric fractures and 36 GT fractures with extension greater than one third of the intertrochanteric width. None of the GT fractures had involvement of the medial cortex.

Our findings suggest that immediate full weight bearing is a safe treatment approach for IIOHFs. Operative fixation or immobilization may be unnecessary for these fractures. Our findings also challenge the clinical necessity of routine MRI scans in patients with GT fractures to assess for fracture progression.