RADIOGRAPHIC DIAGNOSIS: FOREIGN BODY IN THE DISTAL

INTERPHALANGEAL JOINT

LUCAS GIRALDO, W. RICH REDDING

Signalment

SIX-YEAR-OLD, 500kg thoroughbred gelding.

History

A 6-year-old Thoroughbred gelding presented to North

Carolina State University Veterinary Teaching Hospital 2

days after the owner found and removed a nail from the

apex of the frog of the left front foot. The owner reported

that the nail had penetrated the frog to a depth of ap-

proximately 1 in. The horse was not treated with any med-

ication until the referring veterinarian saw the horse 1 day

later, when an intravenous catheter was placed and the

horse was treated with gentamicin. Radiographs of the foot

were made by the referring veterinarian, and no abnor-

malities were noted except for multiple radiopaque areas

that were thought to be artifacts on the outside surface

of the foot and limb. The owner reported a significant

increase in the degree of lameness from the day of nail

removal to the day of presentation at the Veterinary

Teaching Hospital.

Physical Findings, Initial Presentation

At the time of presentation, vital signs were within nor-

mal limits. The horse was grade IV of V lame. A survey

radiographic study of the affected foot was obtained fol-

lowed by a contrast study of the distal interphalangeal

(DIP) joint.

Radiographic Findings, Initial Presentation

Osseous structures within the foot appeared normal.

However, several small (1mm or less) particles of metallic

opacity were seen within the tract of the wound, within the

DIP joint and in the area of the navicular bursa (Figs. 1, 2).

An arthrocentesis was performed to determine whether

there was contamination of the DIP joint because of the

wound. A synovial fluid sample was obtained and 5ml

of iohexal, 5ml of sterile saline, and 2ml (500mg) of

amikacin were injected into the DIP joint. Approximately

2–4min after injection, another radiographic series was

repeated. While the wound did not appear to communicate

with the joint, it was apparent that the contrast medium

extended into all areas where the metallic opacities were

identified on the survey radiographs.

Joint fluid from the DIP joint obtained during the con-

trast study contained 39,000/ml WBC and a protein of

4.5 g/dl.

Radiographic Diagnosis

Multiple foreign bodies in the DIP joint.

Treatment

Before surgery, a catheter was placed in a digital vein in

the region of the proximal phalanx, and a tourniquet was

placed at the level of the metacarpophalangeal joint. One

gram of amikacin in 60ml of lactated ringers was perfused

into the digital vein. Arthroscopic surgery of the DIP joint

and navicular bursa was performed. The DIP palmar

aspect of the joint was approached first. Within the joint,

there was evidence of severe inflammation in the form of

pannus with extensive synovial proliferation within the

palmar recess of the joint. Dispersed throughout the joint,

particles of brown debris were embedded within the syno-

vial tissue (Fig. 3). The pannus and foreign debris was

removed with a 5.5mm synovial resector. The arthroscope

was repositioned and placed into the navicular bursa. At

this point, a communication between the wound, the DIP

joint, and the navicular bursa became evident. After de-

bridement of the navicular bursa with the synovial resector,

the arthroscope was repositioned to explore the dorsal as-

pect of the DIP joint. The pannus and foreign debris

present in the dorsal aspect of the joint was removed with

the synovial resector. The tourniquet was removed, and the

horse recovered from anesthesia uneventfully.

A postoperative lateral radiograph of the left front foot

was made. Although the metallic opacities were fewer in

number than on previous radiographs, there was debris still

present in the dorsal proximal regions of the DIP joint.

The horse was discharged 4 weeks after presentation with

continued treatment using oral antibiotics and phenylbuta-

zone. The horse was walking comfortably when discharged,

and remains sound for trail riding 4 years after surgery.

Address correspondence and reprint requests to Dr. Redding, at theabove address. E-mail: rich_redding@ncsu.edu

Received July 22, 2002; accepted for publication December 23, 2004.doi: 10.1111/j.1740-8261.2005.00055.x

From the Department of Clinical Sciences, College of Veterinary Med-icine, North Carolina State University, 4700 Hillsborough St, Raleigh, NC27606.

304

Discussion

Penetrating wounds that involve the closed synovial

spaces, such as those received from nails into the navicular

bursa, can result in severe septic arthritis and a poor prog-

nosis. A puncture wound may also enter the DIP joint or

digital sheath depending on the direction of the penetra-

tion. A septic process originally involving the navicular

bursa can extend into the DIP joint or the digital tendon

sheath. It is therefore critical to carefully and accurately

assess each structure for contamination or evidence of in-

fection.

Radiographic imaging is a valuable tool in the diagnosis

of septic navicular bursitis.1 When the nail or foreign body

is found it should be left in place and a lateral and dors-

opalmar radiograph taken to allow assessment of the depth

and involvement of the foreign body relative to the

navicular region.2 Sinography (fistulography) can be used

to demonstrate filling of the bursa and DIP joint with

positive contrast medium and support a diagnosis of septic

navicular bursitis.1 In this horse, a communication between

the wound, the navicular bursa, and the DIP joint was

identified. Because of the history and clinical signs, septic

arthritis of the DIP joint and/or septic bursitis of the

navicular bursa was suspected. To more accurately deter-

mine which structures were involved, contrast arthrogra-

phy was performed. Radiographic contrast medium can be

injected into a puncture wound or fistulous tract by place-

ment of a catheter or teat cannula. Enough contrast me-

dium should be used to fill the fistula and associated tissue.

The presence of contrast material within a synovial struc-

ture is definitive evidence of penetration, and sepsis should

be treated aggressively.1–4

This report also emphasized the importance of proper

foot preparation to minimize the chance that significant

foreign objects will be misinterpreted as superficial debris

and/or technical artifacts such as dirt within the cassette.

REFERENCES

1. Van Harreveld PD, Gaughan EM, Biller DS. Diagnosis and treat-ment of septic navicular bursitis in horses. Equine Pract 2000;22:10–13.

2. Gilbson KT, Mcllwraith CW, Park RD. A radiographic study of thedistal interphalangeal joint and navicular bursa of the horse. Vet Radiol1990;31:22–25.

3. Gaughan EM. Septic navicular bursitis in horses. Compend ContinEduc Pract Vet 1995;17:1064–1070.

4. Richardson GL, Pascoe JR, Meagher D. Puncture wounds of thehoof in horses. Compend Contin Educ Pract Vet 1986;8:S379–S388.

Fig. 1. Lateral radiograph of the foot. There is radiopaque material in thedorsal and palmar recesses of the distal interphalangeal joint.

Fig. 2. Dorso 651 proximal palmarodistal radiograph of the digit. Thereis radiopaque material throughout the dorsal recess of the distal inter-phalangeal joint.

Fig. 3. Photo taken during arthroscopy. There is debris present within thedistal interphalangeal joint.

305Foreign Body in the DIP JointVol. 46, No. 4