Comparison between Hip Internal Rotation Assistive Device and Conventional Radiograph Positioning: An Experimental Study

INTRODUCTION: Plain anteroposterior radiograph of the hip plays an important role in diagnosing hip pathology. However, one of the most common mistakes is image distortion because the hip is externally rotated due to natural femoral neck anteversion. Thus, the lower extremities should be internally rotated by 15°-20°. The researchers developed a hip internal rotation assistive device and compared it with conventional radiograph positioning.

MATERIALS AND METHODS: A hip internal rotation assistive device was designed. This study consisted of 20 volunteers without clinical hip pathology. The volunteers were informed to do a hip radiograph twice to compare the efficacy of the developed device with a conventional positioning. The thickness of the lesser trochanter (TLT) was measured and interpreted by an orthopedist and a radiologist. Statistical significance and inter- and intra-observer reliabilities were analysed.

RESULTS: According to the orthopaedist's measurement, the mean TLT distance was 4.42 + 3.2mm and 4.97 + 3.16mm for the conventional technique and assistive device, respectively, without statistical significance between both groups (p = 0.05). Consistent with the musculoskeletal radiologist, the mean TLT distance was 4.00 + 2.06mm for the conventional technique and 3.92 + 2.27mm for the assistive device, without statistical significance between both groups (p = 0.56). Intra-observer reliability was 0.900 and 0.898 for the orthopaedist and the radiologist, respectively. Interobserver reliability of the assistive device and conventional technique were 0.800 and 0.588, respectively.

CONCLUSION: The efficacy of the developed device was similar to that of the conventional technique. Inter/intra-observer reliabilities were at a good agreement level in both methods. The developed device would also be useful in clinical applications, especially in decreasing unnecessary radiation exposure of medical personnel.