How to read foot X-rays?

Next to hand X-rays foot X-rays are an important investigation that patients with inflammatory arthritis. There is a need to have a systematic approach of reading a foot X-ray.

Normal foot X-rays

Usually AP and oblique views are taken.

	X-ray feet AP and oblique AP: The fore foot and mid-foot are seen. The hind foot is not. The phalanges, metartarsal bones are seen Proximal interphalangeal joints, metatarso-phalangeal joints and mid-tarsal joints are seen. Hind foot bones and sub-talar joints are not seen. After describing the type of X-ray one could proceed with talking about (1) bone health, (2) soft tissues, (3) joint space, (4) erosions and (5) malalignment
Figure 1
	X-Ray right foot AP and oblique Bone density is normal There is a soft tissue next to the first MTP join There is a reduction of joint space of the first MTP joint. There is a well-corticated cystic lesion/healed erosion at the head of the first metatarsal. Diagnosis: Chronic gout

Figure 2
	X-ray right foot AP and oblique There is osteopenia Soft tissues are normal The DIP, PIP and MTP are well seen and normal There is a radio-dense lesion around a fracture in the second metatarsal bone Diagnosis: Fracture with callus second metatarsal bone.

Worksheet
Fig. 1:

Fig. 2:

Fig. 3:

Fig. 4:

Previous answers

• X-Ray knees AP view
• There is osteopenia
• There is bi-compartmental (lateral more than medial) reduction of both knees
• The lower end of femur is irregular
• There is increased sclerosis of the lower end of femur

Diagnosis: AVN lower end of femur with secondary osteoarthritis

• X-ray Knee lateral view
• There is complete absence of patella
• Flabella is seen posteriorly

Diagnosis: Absent patella

• X-ray Knees AP view
• Lower end of knee seen
• There is soft tissue seen at the joint.
• The epiphysis of the bones has not fused
• There is widening of the metaphyseal plate

Diagnosis: Rickets

• X-Ray knee lateral view
• There is no osteoporosis
• There are multiple partially radio-dense nodules observed in the knee joint
• There is beaking of patella

• X-Ray knee lateral view
• There is evidence of prosthesis at the lower end
• The femoral component has loosed and there is total loss of the bony cortex at the anterior lower end of femur
• There is periosteal reaction

Diagnosis: Periprosthetic loosening probably due to infection

1. X-ray knee AP view
2. There is an expansile cystic lesion in the lower end of femur with some internal septations
3. The joint space looks normal

Diagnosis: Aneurysmal bone cyst osteoclastoma