Type 1: Wing or alar. Non articular. Most common.
Type 2: Articular
Type 3: Mid sagittal articular.
Type 4: Articular fracture of extensor process.
Type 5: Commuted (many small pieces). Often secondary to bone infection.
Type 6: Rim fracture. Treated like wing fracture. Secondary to laminitis and/or pedal osteitis.
Type 7: Non articular foal fracture. Common, fast healing.

Clinical signs:
Acute onset of moderate to severe lameness. Fist 24 hours increase of inflammation causes increase to Obel 4-5 (severe) lameness. Increased pulse; if paramedian (one side or the other), possibly pulse will be heavier on affected side. Increased temperature. If articular, possible coffin joint effusion (swelling at coronary band on front side of hoof). Positive to hoof testers, but be aware that a negative reading may only mean the location is not available to the testers.

Radiographs. If nothing is seen immediately, veterinarians often retry at 10-12 days when they show up better.

Nuclear scintigraphy. Bone phase scintigraphy can identify acute distal phalangeal fractures before they are visible on radiography.

Causes:
Trauma from force on a solid object, speed, or footing. Can also be caused by a primary pathology such as laminitis or pedal osteitis.

Treatment:
Types 1 & 5 – Immobilize fracture/ prevent expansion of hoof wall, and reduce or remove frog pressure for 2-3 rotations of 4-6 weeks. If not sound at this point, consider a year off for recovery. Depending on location of fracture, occasionally wedges are indicated to relieve stress on DDFT and palmar process.

Consider keeping shod in bar shoes and clips.

Type 2 & 3 – Immobilize and possible surgery of differing degrees. Shoe and disinfect foot prior to surgery.

Type 6 – Secondary to laminitis and/or pedal osteitis? Add treatment for underlying cause.

Prognosis:
For articular fractures, there is a possibility of residual degenerative joint disease (DJD).

Should remain in clipped bar shoe.

Many horses with proper treatment and recovery can return to performance after a year or so. It is certainly case dependent. There have been numerous studies on the subject and many are contrary to each other.

Type 7 – Confine for 6-8 weeks or until bony union is evident. DO NOT MECHANICALLY BIND HOOF.

Type 1 P3 fracture

A Type 1 coffin bone fracture. This is a good look at how to set up a bar shoe to remove contact with the frog and use equicast to immobilize the hoof. You can read the pathology article here to learn more.

Effect of hoof trimming on the occurrence of distal phalangeal palmar process fractures in foals.

Kaneps AJ, O’Brien TR, Willits NG, et al. Effect of hoof trimming on the occurrence of distal phalangeal palmar process fractures in foals. Proc Am Assoc Equine Pract 1995;41:251-252.