Sacral insufficiency fractures are an often unsuspected cause of low back pain in elderly women with osteoporosis who have sustained minimal or no trauma. Many of the references in the literature advocate bed rest initially; however, we support early mobilization, because most of these fractures are stable and require no surgical intervention. With good pain control, patients can begin progressive ambulation with assistive devices in a supervised environment and minimize the complications of immobility.

Sacral insufficiency fractures (SIF) are a type of stress fracture that occur primarily in postmenopausal women. They were first described in 1982 by Lourie and have since been frequently overlooked as a cause of low back, buttock, or groin pain. We present two cases of SIF to demonstrate the clinical presentation, diagnosis, and treatment of patients with SIF. Both patients were elderly women with complaints of pelvic and low back pain in the absence of significant trauma. Physical examination was significant for marked sacral tenderness. Diagnostic imaging supported the diagnosis of SIF. Both patients underwent early rehabilitation, including early ambulation, and had good functional outcomes. These patients serve to illustrate how conservative treatment yields excellent clinical results in the majority of patients, with most reporting improvement within 1-2 weeks after fracture and complete resolution of symptoms after 6-12 months of treatment.

The purpose of this study was to determine whether the time to subjectively fully recover after the performance of exhausting muscular exercise was greater in unstable postpolio as compared with stable postpolio or control subjects. Twenty-five unstable (those complaining of declining muscle strength) postpolio, 16 stable (those denying declining muscle strength) postpolio, and 25 control subjects performed an isometric contraction of the knee extensor (quadriceps femoris) musculature at 40% of maximal torque until they were no longer able to do so. Five-second maximal effort contractions were made every 30 s through 2 min after the time of failure was reached and then at 1-min intervals through 10 min after failure was reached. Subjects reported the duration of time required to subjectively fully recover from this activity. Choices of "less than 1 day," "1 day," "2 days," etc., up to "greater than 2 wk" were given to the subjects for their response. Analysis was by nonparametric ANOVA and appropriate post hoc comparison procedures. Unstable postpolio subjects reported a greater recovery time than either the stable postpolio or control subjects (mean +/- SD of 2.6 +/- 3.0 days, 0.6 +/- 1.0 days, and 0.7 +/- 1.1 days, respectively, P < 0.05). Thus, the reported recovery time from exhausting isometric muscular exercise was found to be greater in unstable postpolio subjects than stable postpolio or control subjects. The cause for this finding is unknown and requires further investigation.