Virtually eliminate errors in positioning calibration markers on hip patients. KingMark™ allows you to routinely and accurately calculate the radiological magnification of the hip using two separate radio-opaque markers. In clinical trials, KingMark performed four times more accurately than the conventional, single-ball marker.

Double markers

KingMark uses two separate markers—one behind the pelvis and the other in front, as the patient lies supine. The anterior marker is a flexible strap that secures radio-opaque balls at regular intervals. The posterior marker is a radiolucent pad with steel rods embedded in a vertical row.

Two is better than one

Previously, accurate calibration relied on a single marker being exactly located in the coronal plane of the hips—requiring special expertise and extra time. Surgeons couldn’t easily identify misplaced markers on radiographs, sometimes leading to incorrect results.


  • Quick and easy to apply correctly—patient is centrally positioned on the posterior pad. The anterior ball-strip is placed midline over the suprapubic area.
  • Accurate calibration doesn’t depend on exact positioning by trained experts.
  • It is visually apparent on the radiograph when markers are incorrectly positioned, so surgeons aren’t misled.
Accurate in all sizes of patients

Accurate in all sizes of patients

Single markers can be difficult to use in very large patients. Often markers are not imaged when placed adjancent to the patient's hips because the pelvis is wider than the x-ray detector. Also positioning a marker between the patient’s thighs is socially unacceptable by both patient and technician.

Since KingMark is positioned midline, it always appears within the radiograph. The correct positioning technique is the same for all sizes of patients and is not awkward or invasive. Even on very large patients, calibration accuracy is not significantly diminished.

Automatic calibration
in TraumaCad

TraumaCad will automatically detect the presence of KingMark in an x-ray, determine the magnification percentage, and size the image accurately.

For surgeons who need to perform manual calibration on radiographs with KingMark, precise magnification values can be obtained by using the KingMark Calculator.

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White Papers

A novel method of accurately calculating the radiographic magnification of the hip.

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The Journal of Bone and Joint Surgery, British

The Journal of Bone and Joint Surgery (British Volume) has made the article above freely available. JBJS (Br) publishes the highest quality scientific research and leading reviews across all orthopaedic specialties. Stay up to date with free table of contents alerts