Incomplete Ossification of Incomplete Ossification of the Humeral Condyle the Humeral Condyle

(IOHC) in Dogs(IOHC) in Dogs

Bill LeeBill Lee

#103957 #103957

IOHCIOHC

““Max” MatthewsMax” Matthews eleven year old male German Shorthair eleven year old male German Shorthair

Pointer Pointer fractured left humerus chasing a ball in the fractured left humerus chasing a ball in the

yard yard 103957103957

IOHCIOHC ““Max” MatthewsMax” Matthews Postop images Postop images 103957103957

IOHCIOHC

IOHC described in 28 skeletally mature IOHC described in 28 skeletally mature spaniels (Marcellin-Little, Vet. Surg. 1994)spaniels (Marcellin-Little, Vet. Surg. 1994)

Spaniels predisposedSpaniels predisposed Cocker, Brittany, Boykin, Springer, Cocker, Brittany, Boykin, Springer,

Clumber, Cavalier King CharlesClumber, Cavalier King Charles Rottweiler, LabradorRottweiler, Labrador Humeral condylar fractures (HCF) occur Humeral condylar fractures (HCF) occur

after minor trauma in these dogsafter minor trauma in these dogs

IOHCIOHC

Cause IOHC unknown: polygenic, Cause IOHC unknown: polygenic, recessive mode of inheritancerecessive mode of inheritance

Some suggest elbow incongruity (reduced Some suggest elbow incongruity (reduced growth of distal ulnar physis) as causativegrowth of distal ulnar physis) as causative

Male dogs predisposed, possibly b/c Male dogs predisposed, possibly b/c estrogen has stim. effect on epiphyseal estrogen has stim. effect on epiphyseal maturationmaturation

IOHCIOHC

Normal condylar ossification complete @ Normal condylar ossification complete @ 8-12 weeks8-12 weeks

2 main oss. Centers (med. & lat. Aspect of 2 main oss. Centers (med. & lat. Aspect of condyle) fail to fusecondyle) fail to fuse

Remain separated by fibrous tiss. Remain separated by fibrous tiss.

IOHCIOHC

Classically, present with lameness or HCF Classically, present with lameness or HCF at mean age = 6 yrs (range 2-12)at mean age = 6 yrs (range 2-12)

Some reports suggest obesity as a risk Some reports suggest obesity as a risk factorfactor

All dogs w/ IOHC are bilaterally affected All dogs w/ IOHC are bilaterally affected per Dr. Marcellinper Dr. Marcellin

DxDx

Radiographic views: flexed L-M, Radiographic views: flexed L-M, hyperflexed L-M, Cr15hyperflexed L-M, Cr15°°MCdLOMCdLO

55° off shown to obscure visualization° off shown to obscure visualization Radiolucent line on CrCd view, often Radiolucent line on CrCd view, often

approx. 1 mm wide, with surrounding approx. 1 mm wide, with surrounding sclerosissclerosis

Complete (spans articular surface to Complete (spans articular surface to supratrochlear foramen) or incompletesupratrochlear foramen) or incomplete

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92% of dogs with IOHC have concurrent 92% of dogs with IOHC have concurrent DJD, 25% have FMCPDJD, 25% have FMCP

““Y” (93%), lat.(36%), med.(11%) fxs; lat. Y” (93%), lat.(36%), med.(11%) fxs; lat. more common than med. (art. w/ radial more common than med. (art. w/ radial head)head)

In imm. Dogs, IOHC cannot be confirmed. In imm. Dogs, IOHC cannot be confirmed. Must repeat rads after skeletal maturityMust repeat rads after skeletal maturity

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C.T. features of IOHCC.T. features of IOHC (Carrerra I, et. al. (Carrerra I, et. al. Vet. Surg. 2008.)Vet. Surg. 2008.)

C.T. more sens. and spec. that rad.C.T. more sens. and spec. that rad. MPR at the level of the medial coronoid MPR at the level of the medial coronoid

apex (base and apex)apex (base and apex) Joint space at humero-uln. art. wider than Joint space at humero-uln. art. wider than

humero-rad. art. (incongruent)humero-rad. art. (incongruent) Sig. diff. than normal elbows (apex > base)Sig. diff. than normal elbows (apex > base)

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TxTx

Sx: transcond. lag screw, bone plates, etcSx: transcond. lag screw, bone plates, etc IOHC often does not heal after Sx, fibrous IOHC often does not heal after Sx, fibrous

tiss. persiststiss. persists Prophylactic transcond. Screw for IOHC Prophylactic transcond. Screw for IOHC

w/out HCF appears to prevent lameness, w/out HCF appears to prevent lameness, fxs – no prospective studiesfxs – no prospective studies