This is not just a case of the month but a case of the decade!

It was a Saturday morning. An emergency call from a client indicated that her new horse was extremely lame - he was on 3 legs. Since she and her family live quite a distance away I suggested they load the horse into their trailer and meet me at the clinic. Upon unloading I was amazed at how lame he was – truly “fracture lame” in the affected hind limb. After examining the limb and lifting the foot I discovered the head of a large nail penetrating the foot through one of the grooves that lie along the frog!

One’s natural instinct is to pull out the nail but you should never do this before x-rays are taken!

We hobbled into our exam area and immediately took the following digital radiographs. Wow!

What vital structures did this 6 inch nail penetrate? 1) the sensitive part of the frog (corium cunei), 2) the deep digital flexor tendon 3) the navicular bursa (bursa podotrochlearis) 4) the plantar proximal recess of the coffin joint

With dirt and probable rust being deposited in so many vital areas infection had already set in. The horse’s temperature was elevated even though the spike had gone in sometime during the night. Construction had been going on at the property and a worker had dropped the nail.

The prognosis for treatment without surgery was extremely poor. Why? Because the coffin joint and navicular bursa are all closed sacs producing a protein rich fluid that is an excellent medium for bacteria to grow in. The bacteria invade and replicate in the synovial membranes of these structures. They destroy cartilage in the joints and cause thickening and adhesions in the soft tissue structures.

Any surgical treatment would need to provide thorough evacuation of the macroscopic and microscopic debris – rust all the way down to bacteria!

Because of the drastic lameness, trapped infection and guarded prognosis even with surgery I offered euthanasia as a logical consideration for the owner. To my surprise she would have no part of it and wanted me to try surgery to save her horse.

A surgical plan is always a necessity.

A surgical approach to the navicular bursa called a “street nail procedure” was used in the past. It involves removing the frog and making a window in the deep flexor tendon. I had found this procedure much too painful with permanent lameness resulting – for an athlete I felt this was not an option.

An advanced arthroscopy course had taught me an arthroscopic approach to the navicular bursa through the digital sheath. This “tenoscopic” approach is considered minimally invasive surgery and I chose this approach to decrease complications.

Being a weekend I had to call in my surgical team – they all appeared graciously and we went to work. Since infection and pain had resulted in low grade shock, antibiotics, fluids and pain medication were administered preoperatively.

Surgery: The nail was left in place until after induction in order to avoid the tract closing over prematurely and trapping bacteria. The pastern and fetlock were clipped and the surgical sites were shaved followed by a mouth rinse, induction, intubation (30mm tube) & positioning in dorsal recumbency. Mandibular artery was catheterized for blood pressure.

After induction all shoes were pulled and the affected hind foot was trimmed with a hoof knife. The foot, pastern and fetlock were surgically scrubbed followed by removal of the nail. The nail was a twisted type and removal was followed by a bloody pussy discharge indicative of an established infection. The nail hole was debrided (pared away) up to sensitive tissue with a narrow abscess knife and rongeurs. Another scrub was done and the limb was draped for tenoscopy. (looking at tendonous structures using an arthroscope)

A needle was placed into the coffin joint dorsally under fluoroscopic guidance. A murky looking joint fluid was discovered indicative of coffin joint infection. A sample was taken for culture & cytology. Carbocaine anesthetic & contrast dye was injected and communicated with the navicular bursa thereby confirming its involvement.

The digital sheath was distended and a proximal entry allowed the arthroscope to slide down the sheath into the affected area. The area between the digital cushion and deep flexor penetration was irrigated first. The arthroscope was then repositioned over top of the flexor tendon and inserted into the bursa as confirmed by fluoroscopy. Visibility was poor but a spinal needle placed into the navicular bursa allowed super flow of LR which also came out the needle placed in the coffin joint dorsally. The motorized resector was used to debride the puncture site along its entire course up to its most proximal position. This was observed fluoroscopically.

Irrigation continued until there was free flow of clean fluid from all portals. The incisions were closed with 2-0 Ethilon.

The ventral nail puncture hole was packed with Neosporin and the sole was packed with gauze soaked in betadine solution.

The limb was bandaged for recovery using Neosporin, sterile gauze and elastoplast. A sterile sticky drape was applied to prevent contamination.. Recovery was smooth & uneventful. The demand valve was used to administer oxygen until extubation.

Postop findings: once the freezing had worn off the horse was still non weight bearing when standing - still lame 5/5.

Antibiotics continued every 6 hrs with dressing changes as needed.

By Sunday PM the horse’s ability to bear weight on the limb steadily improved and his temp had remained normal. The dressing was changed and the inisions looked good. He was discharged several days later.

He never looked back and remains sound to this day!