[Radiological and scintigraphic evaluation of hip prostheses (author's transl)]

Area of Science:

• Orthopedic surgery
• Nuclear medicine
• Radiology

Background:

• Radiological assessment of hip prostheses can be inconclusive.
• Bone scintigraphy offers valuable supplementary information for prosthesis evaluation.

Purpose of the Study:

• To elucidate the role of bone scintigraphy in diagnosing hip prosthesis instability.
• To define the interpretation criteria for scintigraphic findings in relation to radiological data.

Main Methods:

• Analysis of radiological and bone scintigraphic findings in patients with hip prostheses.
• Correlation of scintigraphic uptake patterns (intensity, distribution, localization) with radiographic signs of instability.

Main Results:

• Abnormal bone uptake on scintigraphy indicates potential hip prosthesis instability due to mechanical stress.
• Increased scintigraphic uptake can also result from inflammatory changes, healing, or soft tissue calcification, not solely loosening.
• Radiographic signs of instability combined with corresponding increased radioactivity confirm loosening.
• Early loosening of the prosthesis stem may be detected scintigraphically before radiographic changes appear.
• Increased acetabular uptake in stable prostheses requires cautious interpretation regarding loosening.

Conclusions:

• Bone scintigraphy is a crucial adjunct to radiography for hip prosthesis evaluation.
• Accurate interpretation requires considering uptake intensity, distribution, localization, and correlation with radiographic findings.
• Scintigraphy can detect early loosening, but positive findings must be critically assessed to avoid false positives.