Reliability of relation between greater trochanter and center of rotation of femoral head in Indian population.

PURPOSE

Accurate limb length restoration forms an important aspect of reconstructive surgeries around the hip joint. Among the various intraoperative methods for accurate limb length restoration, the relation between the greater trochanter and the center of the femoral head has been conventionally used owing to its simplicity and replicability. The current study aims to study the normal relation between the greater trochanter and the center of rotation of the femoral head, its population-based variation and its gender-based and contralateral differences in the Indian population.

METHODS

Standard anteroposterior radiographs of normal hip joints with the proximal femur, performed over a one year period were studied. A software-based analysis was conducted to measure the difference between the levels of the greater trochanteric tip and the center of the femoral head along the longitudinal axis of the femur. The measurements among the male and female cases and the contralateral sides were compared.

RESULTS

The greater trochanteric tip lies at a higher level than the center of rotation of the femoral head by a mean difference of 9.20 ± 5.30 mm. No significant differences were observed among male and female groups and between the contralateral hip joints. Intraobserver and Interobserver reliability were high.

CONCLUSIONS

The tip of the greater trochanter and the center of the femoral head do not lie at the same level. This differential relation should be considered during the reconstructive surgeries around the hip joint to prevent an inadvertent limb length discrepancy. Considering the wide interindividual variations, this difference cannot be generalized for all the patients and restoring it to the contralateral normal hip would be more appropriate.