The foot contains 26 bones and 33 joints. Dislocation of any of the joint of the foot can cause severe pain. Dislocation of the foot joint affects the weight transmission through the arch of the foot. Body weight is transmitted to ground through the arch of the foot while standing, walking, and jogging.
It is believed that the arch of the foot is mechanically very strong and designed to shift the weight to front half and back half of the foot during daily activities. Gaments, tendons, and muscles support bones in maintaining normal anatomical position. The foot is further divided into 3 sections described as front section (fore-foot), the middle section (mid-foot) and back section (hind-foot).
Fore-foot is supported by phalanges (toes) and distal ½ of the metatarsal bones. Mid-foot is supported by proximal ½ of the metatarsal bone as well as cuboid, navicular and cuneiform bone. Mid-foot joints form the arch of the foot. Hind-foot is supported by talus and calcaneus bone. Symptoms of foot joint dislocation are spread into one of the three sections.
Types of Foot Joint Dislocation:
Fore-Foot Joint Dislocation
Forefoot consists of 5 toes and anterior 1/3rd of the arch of the foot. 14 phalanges and anterior 1/2 of 5 metatarsal bones support fore-foot.
14 Joints of Forefoot are as follows:
Dislocation of any of the above joint results in acute severe pain and associated symptoms of dislocation.
Mid-Foot Joint Dislocation:
The arch of the foot is located in Mid-foot. Following bones support the mid-foot-
- Posterior 1/2 of 5 metatarsal bones.
- 3 Cuneiform bone
- Cuboid bone and
- Navicular bone.
Joints of Mid-foot are as Follows-
- Metatarso-Cuneiform Joint- 1 joint
- Metatarso-Cuboid- 4 joints
- Inter-Metatarsal Joint- 4 joints
- Naviculo-Cuneiform joint- 1 joint
- Naviculo-Cuboid joint- 3 joints
- Cuneiform-Cuboid Joint- 1 joint
- Inter-Cuboid Joint- 2 joints
Dislocation of any of the above joint results in symptoms spread over arch of foot and mid-foot.
Hind-Foot Joint Dislocation:
Hind-foot is the continuation of the ankle joint and posterior ½ of the arch of the foot. Bones supporting hind-foot are talus, calcaneal, posterior ½ of Navicular and 3 cuboid bones.
The 3 joint of the Hind Foot are as follows:
Symptoms & Signs of Foot Joint Dislocation
1. Acute Foot Pain
- Foot Pain is described as acute foot pain when pain lasts for less than 3 to 6 months.
- Similarly, chronic foot pain is defined as pain that continues beyond 3 to 6 months.
- Foot pain which is caused by dislocation is always acute and severe during first 3 months.
- Foot pain is linked with severe tenderness over the dislocated joint.
- The skin over dislocated foot joint is bruised, deformed and red.
- Foot pain occurs in one of the 3 sections of the foot.
a.    Fore-foot Pain
- Pain is observed over toe and base of the toe.
- Pain is caused by dislocation of Inter-Phalangeal joints and metatarsophalangeal joint.
- Acute severe pain is often observed following injury or trauma.
- Pain is associated with joint deformity, tenderness, and skin discoloration over the dislocated joint.
b.    Mid-Foot Pain
- Severe foot pain linked with deformity and tenderness in mid-foot following injury or accident suggests possible dislocation of one of the 16 mid-foot joint.
- Foot pain is spread over the arch of the foot.
- Dislocation of mid-foot is divided in front or back of the arch.
c.    Hind-Foot Pain
- Severe foot pain is localized to the back of the arch of the foot.
- Foot pain is localized below and front of the ankle joint.
- Pain is associated with deformity and tenderness over the dislocated joint.
- X-Ray and MRI are necessary to diagnose the dislocation.
2. Intensity of Foot Pain
Foot pain is described as mild, moderate, severe and very severe. Pain is measured as VAS (visual analog score). VAS of the acute and chronic pain is defined as follows-
- VAS zero- no pain
- VAS of 10- optimum severe pain.
- Mild pain- VAS of 1 and 2.
- Moderate pain- VAS of 3 to 5.
- Severe pain- VAS 6 to 8.
- Very severe pain- VAS 9 and 10.
3. Sign of Foot Pain
4. Foot Pain with Activities
- Foot pain at rest- Moderate to severe pain
- Pain with activities- Pain is always severe to very severe in intensity.
5. Joint Deformity
- Protrusion of the dislocated bone is observed under the skin
- The deformity is exaggerated by the hematoma (blood clot) under the skin and subcutaneous tissue.
- Phalangeal dislocation causes deformity over toes.
- Metatarsal bone dislocation causes deformity of the base of the toes.
- Deformity of the joints of the mid-foot is observed over the arch of the foot.
6. Restricted Foot and Toe Movements
- If the patient is unable to bend or move toes then it indicates dislocation of Interphalangeal joint or Metatarsophalangeal joint.
- If the patient is unable to perform internal or external rotation of the foot then it suggests dislocation of joints in mid-foot and hind-foot.
7. Bruising of Skin over Dislocated Joint
a.     Bruising of the Skin over Toes
- Purple discolored skin is observed over dislocated toe
- Bruising is caused by subcutaneous bleeding
- Skin is stretched and tender over the deformed swollen interphalangeal joint.
b.     Bruising over Arch of the Foot
- Purple discolored skin is seen over mid-foot and arch of the foot.
- Bruising is associated with the subcutaneous hematoma (blood clot).
- Skin is stretched and tender over the deformed swollen mid-foot joint.
Which are the different tests which have to be performed before treatment of Foot Dislocation?
Some of the tests which have to be performed before the treatment of Foot Dislocation are: