AABP Fact Sheet - Foundation

1 Page 1 AABP fact SheetINTERDIGITAL HYPERPLASIA (CORN)Authored by the AABP LAMENESSCOMMITTEEI nterdigital hyperplasia (interdigitalfibroma, corn) is a firm, fibrous massthat protrudes from the interdigitalspace of the feet of cattle. Theyoccur sporadically in all breeds ofbeef and dairy cattle, and there maybe a hereditary predisposition insome breeds. Interdigital hyperplasiain multiple feet of young animalsshould be suspected to be hereditaryin nature. PathogenesisInterdigital hyperplasia is formed byhyperplastic interdigital skin. It usuallybegins at the axial surface of the anteriorinterdigital space on the lateral claw ofthe rear limb, and can progress to lesionsspanning the entire interdigital skin irritation from grazing stub-ble or rocky pastures, poor hygiene, mildinterdigital dermatitis or interdigitalphlegmon (foot rot) can result in hyper-plasia.

2 Horn overgrowth may cause thesoles to trap manure in the interdigitalspace, leading to chronic irritation andhyperplasia. Also, excessive splaying ofthe toes from excess body condition,breakdown of interdigital ligaments oran unbalanced foot may cause stretchingof the interdigital skin and predisposecattle to interdigital hyperplasia. Theseconformation defects of the foot mayaccount for the hereditary predispositionin some lines of cattle. Histologically, the lesions consist ofhyperkeratotic and parakeratotic skinwith increased cellularity in the stratumgranulosum and stratum spinosum andevidence of chronic inflammation.

3 If sec-ondary damage is present, evidence ofulceration and local or deep infectionmay be Predisposing FactorsInterdigital hyperplasia may occur inone or multiple feet of a particular ani-mal, and are more common in the rearlimbs than forelimbs. They are alsomore common in heavy animals, particu-larly bulls. TreatmentSmall lesions may not result in lameness,but larger lesions may put mechanicalstresses on the digits, causing mild tomoderate lameness. Severe lameness isusually associated with large ulceratedand/or infected hyperplasias. The infec-tion is usually superficial, but can spreadto deeper interdigital tissues if leftuntreated.

4 The clinical importance ofthe lesion is determined by assessingpain in response to pressure on thelesion. Painful lesions are more likely tocause lameness and thus are more likelyto benefit from surgical interdigital hyperplasias not caus-ing lameness may not need any treat-ment, but should continue to beobserved for signs of enlargement,ulceration or infection. Keeping thefoot balanced through hoof trimmingmay slow the growth of lesions. Largerand/or infected lesions causing lamenessshould be surgically removal of small lesions insound animals should be performedwith caution, as removal commonlycauses lameness, which can be protract-ed in some surgery, animals are best positionedin lateral recumbency with physicaland/or chemical restraint.

5 Surgery can be performed on animalsstanding in a hoof trimming chute, butit is more difficult for the operator tovisualize the lesions due to the dorsallocation of the lesion. The hoovesshould be trimmed to the correct lengthand proper tourniquet should be placed abovethe fetlock to provide regional perfusion or localinterdigital injection of a local anesthet-ic agent should provide adequate surgi-cal anesthesia of the area. Two holes should be drilled through thehoof wall in each claw at the toe andslightly abaxial to the toe. Small diame-ter wire cut into 12 inch lengths shouldbe placed through one hole in eachclaw to facilitate separation of the dig-Important Things to Know About Interdigital HyperplasialInterdigital hyperplasia or corns are firm fibrous masses consisting of hyper-keratotic and parakeratotic skin found in the interdigital space of beef anddairy cattlelThe lesions appear to occur secondary to chronic skin irritation due to envi-ronmental, conformational and hereditary factorslWhere lesions become large and/or infected.

6 Surgical removal is the pre-ferred treatmentlImproved hygiene and appropriate hoof trimming are the keys to preven-tionAABP fact SheetInterdigital Hyperplasia continuedits and exposure of the hyperplasia(Figure 1).The foot should be surgically prepared,taking care to thoroughly disinfect thecrevice between the hyperplasia and theaxial hoof mass can be grasped with tissue ortowel forceps. An inverted V incisionshould be made at the dorsal interdigi-tal space a few millimeters dorsal to thehyperplasia. While putting traction onthe hyperplasia with the forceps, theincision is continued in a wedged-shaped pattern towards the ventralinterdigital space (Figure 2)along theaxial hoof walls and deep into the inter-digital space.

7 Any firmfibrous tissueshould be removed. If the fat pad isencountered and is protruding from theinterdigital space, it should be removedwith blunt dissection, taking care toavoid the distal interdigital cruciate powder should be appliedto the interdigital area. With large post-surgical defects, the interdigital spacecan be packed with sterile gauze or cot-ton(Figure 3). The toes can be wiredtogether to decrease movement of theclaws, but this may not be necessary inhoused animals. The entire foot, includ-ing the solar surface should be incorpo-rated in a tape bandage with or with-out antibiotics are indicated only ifthe interdigital space deep to the hyper-plasia is infected.

8 After-careBandages should be removed and/orreplaced according to the size of thedefect and anticipated healing time. Inmost cases, bandages can be removed atone week. However, total healing timemay be three weeks, and animals mustbe kept in a dry environment until heal-ing is complete. Post-surgical infectionsof the interdigital space from impropercare can be severe and wires can be left in place to wearout, or be removed when healing iscomplete. PreventionGood hygiene and proper hoof care andtrimming will decrease the number ofsporadic cases of interdigital hyperpla-sia.

9 Interdigital hyperplasia caused bypoor conformation is very likely to recur,since the predisposing conformationproblems will usually remain afterremoval of the growth. Animals suspect-ed of having interdigital hyperplasiadue to hereditary factors should beculled or only used for breeding of ter-minal crosses. AABPPage 2 Figure of thehyperplasticgrowth from thedorsal aspect ofthe 3. Post surgical care involv-ing application of a sterile 1. Preparation of the footfor surgery with adequate restraintand the toes wired to allow separa-tion and visualization of the surgi-cal field.