Suspected Hip Fracture: Positioning Without Forcing the Leg
An 82-year-old woman is brought to the emergency department after a fall at home. Her right leg is shortened and externally rotated, and she rates pain 9/10. The ED requests an AP pelvis and a lateral right hip. She weighs 55 kg, takes warfarin (INR 2.8), has a permanent pacemaker, and cannot lie flat without severe pain. She is unable to internally rotate the right leg, and any attempt produces guarding and crying out. The ED doctor wants images within 15 minutes. She is alert and consents. The room is set for a standard supine AP pelvis at 100 cm SID with a grid.
1. Which projections would you take, in what order, and how do you adapt them? Explain what each view contributes and why internal rotation is not attempted.
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Order: AP pelvis first, then a lateral right hip. The AP pelvis is quick, requires no manipulation of the injured limb, and will show a displaced femoral neck, intertrochanteric or pubic ramus fracture in most cases - it gives the ED something to act on inside the 15-minute window.
Do not internally rotate the right leg. Internal rotation is used in a normal hip to bring the femoral neck parallel to the detector and profile it, but in a suspected fracture it can displace a minimally displaced neck fracture and causes severe pain. A modified AP with about 15° cephalad angulation, taken with the leg in its resting position, is the compromise: it opens the neck without moving the limb.
Lateral: a cross-table (horizontal beam) lateral or a Danelius-Miller projection, obtained with the injured leg undisturbed. The lateral is not optional - it defines anteroposterior displacement and rotation, which determines whether the patient goes to theatre for a cannulated screw, a hemiarthroplasty or a dynamic hip screw.
Shielding: gonadal shielding is not useful in this age group and may obscure the field; tight collimation to the hip is the more effective and more honest protection.
2. For the lateral view, describe the geometry, dose and practical constraints you must manage, and what you would do if the patient cannot abduct the unaffected leg.
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Geometry: with the detector placed vertically against the lateral aspect of the hip and the beam horizontal, the object-to-detector distance is large, so magnification increases and sharpness falls. Compensate by keeping the detector as close to the hip as possible using a cassette/detector holder, using the longest SID the room allows, and collimating tightly to the hip and proximal femur.
Dose: the cross-table lateral is not a low-dose view - the beam traverses the pelvis and the contralateral soft tissue. Collimate to the hip, avoid open field, and take one well-prepared exposure rather than a series of exploratory attempts. The patient's 55 kg habitus helps penetration; the pacemaker is above the field and is not a reason to alter technique, though the beam must not be directed at it.
If she cannot abduct the unaffected leg: you cannot place a detector in the groin. Options are a modified cross-table with the detector positioned as far proximally as she can tolerate, or a Clements–Nakayama projection (patient supine, detector in the axilla, beam horizontal and angled to the hip) - but that requires more movement and more pain. Do not force abduction. Escalate for analgesia before attempting; if the hip cannot be lateralised adequately, document why and let the radiologist decide whether CT is required.
Quality criteria: femoral head, neck, both trochanters and the acetabulum visible, adequate penetration, no motion, no overlap of the contralateral hip.
3. The ED doctor is impatient and says 'just pull the leg straight and take the picture'. How do you handle this, and when would you stop and send her for CT instead?
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Handle it directly and briefly. Explain that the AP pelvis is already available and answers most of the immediate question, that deliberately pulling an externally rotated, shortened leg risks converting a stable fracture into a displaced one, and that the lateral is being obtained with the limb undisturbed. Offer the practical trade-off: 'AP is done now, the lateral needs three to four more minutes and no leg movement.' Offer to speak to the radiologist if the doctor believes CT is indicated - making the escalation easy is more effective than refusing.
Stop and escalate for CT when:
- the patient's pain cannot be controlled enough to obtain a diagnostic lateral despite adequate analgesia;
- the AP is normal but clinical suspicion remains high (occult femoral neck fracture);
- there is a complex acetabular or comminuted fracture where plain films will not answer the surgical question;
- there is a pacemaker, prosthesis or previous surgery in the region complicating interpretation.
Document every modification: the resting position used, the reason, the views obtained, the pain score and analgesia given, and the fact the request was discussed with the referring doctor. A documented, reasoned deviation from the standard projection is good practice; a silent one is not.