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epicondylar crest can lead to lateral humeralcondylar fracture (HCF) once the condylesare unattached. This shear stress is furthercompounded by incomplete ossification ofthe humeral condyles (IOHC), leaving thelateral epicondylar crest solely supportingthe humeral capitulum.1,2 Spaniels are pre-disposed to IOHC and intercondylar/uni-condylar fractures.1,3 Implant failurefollowing HCF repair has been reported andmay be associated with nonunion.4,5 A highincidence of screw failure has been reportedin repair of HCF in Springer Spaniels.6 Thispaper describes a novel technique for repairof HCF using more implants than just a lagscrew in the belief that there should be alower incidence of screw breakage. Theauthors cannot claim that this technique isbetter at preventing screw breakage as thecase number and postoperative time are notsufficiently high in this study to make thisconclusion, but the authors are of the opin-ion that the results do warrant further inves-tigation of the technique.

Use of a Plate and Screws to RepairLateral Humeral CondylarFractures in 10 DogsWilliam McCartney, MVB, CertSAO, Dipl ECVS, PhD, MRCVS1,2

Bryan MacDonald, BSc, MSc, PhD, C Eng2

Damien Comiskey, B Eng2

Caroline B. Garvan, MVB, CertPGFS3

1Marie Louise Veterinary HospitalBaldoyle, DublinRepublic of Ireland2Medical Device and Orthopaedic Research Centre (MDORC)Dublin City UniversityGlasnevin, DublinRepublic of Ireland3Dublin Institute of TechnologyDublinRepublic of Ireland

KEY WORDS: humeral, condylar, frac-tures, lateral, finite element

ABSTRACTFracture of the lateral humeral condyle(HCF) is a common injury, and the treat-ment by lag screw fixation is accepted asthe method of choice. If the screw breaks,however, the dog will not have a satisfacto-ry outcome. Screws can break due to non-union, long periods of cyclic loading, andinsufficient diameter. A plate can beapplied to the lateral aspect of the humerusutilizing the bottom plate hole as thetranscondylar screw hole and another screwin the more proximal plate hole to shareloading and distribute the forces of cyclicalloading. The results from using a lateralplate on the distal humerus in the 10 casesin this study are encouraging and warrantfurther investigation.

INTRODUCTIONShear forces on the relatively small lateral

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METHODS All 10 dogs were English Springer Spaniels(6 male, 4 female); the average age was 4years and the age range was 2 to 8 years.There was no history of a major traumaticincident; 1 dog sustained the fracture whilstjumping (Figure 1). Although prodromallameness was noted, no cases had radi-ographs taken at that point to check forIOHC of the opposite leg. Routine anaesthe-sia, analgesia, and aseptic procedures werefollowed for each case and all operationswere performed by the same surgeon (WMcC). A caudolateral approach to the elbowwas made and the fracture site/surface andlateral humerus were cleared of any tissuethat would either hinder healing or plateapplication. Any tissue, such as fibrocarti-laginous tissue, on the fragment surfaceswas curetted away to leave a bleeding bonesurface. Using pointed reduction forcepsand confirming alignment by reference tothe lateral epicondylar crest, the fracturewas held in reduction. A 1.1-mm short pinwas drilled parallel to the projected direc-tion of the transcondylar lag screw andkeeping reference to where the plate wouldbe lying so as not to impede its contouring.An incision was made from the lateral epi-condylar eminence cranially in a 45-degreeangle and the muscles retracted to allowvisualization of the site on the lateral epi-condyle for lag screw placement. A pilothole for a 3.5 mm or 4.5-mm screw wasdrilled, following by over drilling of the lat-eral epicondyle portion in preparation forlag screw insertion. A pre-contoured pre-cut3.5-mm reconstruction plate (RCP) was trialfitted to the lateral aspect of the humerusallowing for at least one hole above theproximal fracture line (Figure 2). The RCPwas cut and contoured in the craniocaudalplane using the contralateral limb x-rayprior to surgery. It should be noted that a3.5-mm and a 4.5-mm screw will fit into thehole of a 2.7-mm RCP and 3.5-mm RCP,respectively (Figures 3 and 4). To assistintraoperative contouring, the distal holewas pressed firmly onto the center of the lag

screw hole already created. Additionallypartial placement of a screw into thetranscondylar hole through distal RCP holewas helpful to assess degree of contouringneeded, which was always significant. Oncethis stage of contouring was finished, thescrew was inserted into the bottom screw

Figure 1. Radiograph of fracture sustainedfrom jumping.

Figure 2. Lateral view of repair.

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hole and fully tightened; if further contour-ing was deemed necessary at this point, thescrew was either partially unscrewed toallow more contouring in situ or removedand free hand contouring applied. Once theplate was lying against the bone along thelateral humerus, the top 3.5-mm screw orscrews as the case concerned were inserted.Following routine closure, the leg was band-aged for 5 days and passive flexion andextension was started by the owner on thefifth day.

RESULTSThere were no incidences of implant failureafter 1 year follow-up in the 7 cases wherecontact was possible. Postoperative radi-ographic examination was used to confirmfracture healing, and no persistence of thefracture was found postoperatively. Six ofthe cases had intermittent stiffness and alldogs had reduced range of motion byapproximately 15%-20% as judged by thesurgeon at the last follow-up exam. Thedegree of post traumatic osteoarthritis in allcases was classed as either mild or minimalusing the last postoperative radiograph. Thepostoperative follow-up examination was inthe period 16 weeks to 6 months postopera-tive, and long-term follow-up was 1 year for7 cases.

DISCUSSIONA single transcondylar lag screw with anoptional anti-rotational k wire is the recom-mended method of repair for lateral HCF.3

Implant failure of the transcondylar lagscrew is a recognized problem but its inci-dence is unknown, though it may be associ-ated with non-union of the fracture.4 Implantfailure by screw breakage is a devastatingcomplication which is difficult to resolvesatisfactorily.4,7 There maybe a higher inci-dence of implant failure in English SpringerSpaniels from the authors experience andothers.5 For this reason, the authors used alateral plate and screws to provide addition-al stability to HCF in English SpringerSpaniels.

There is a high incidence of post trau-matic osteoarthritis (PTO) following HCFrepair, and limb function should be expectedto decline over time.8 Additionally, it isexpected that all dogs will have reducedrange of motion following HCF repair.8 Thisfinding does not correlate with otherstudies,9,10 were the incidence of PTO ismuch lower. However, the case types arenot the same between these studies and itwould seem to indicate that young dogs anddogs weighing more than 7 kg will havebetter outcomes with less PTO and reduced

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Figure 3. Radiographic view showing a 4.5-mm screw used in the distal hole of a 3.5-mmreconstruction plate.

Figure 4. Radiographic view showing a 3.5-mm screw in the distal hole of a 2.7-mmreconstruction plate.

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range of motion. The technique described inthis study was not used in young dogs andis not suitable for use in small breeds. Onlylarger dogs were candidates for the tech-nique described here, which would meanthat the outcomes will expect to have higherPTO and reduced range of motion. Theeffect of the plate lying over the extensormuscle origins is unknown, but there was noclinical evidence of a problem at the site byevidence of thickening, swelling, or pain.

The presence of IOHC could lead to anon-union in some cases of HCF and thesedogs could be candidates for implant fail-ure. In 2 reports in the literature involvingtreatment of IOHC,2 some cases that hadlag screws inserted still had a radiolucentline long after surgery. Continued repeti-tive loading could lead to a stress raiserfracture of the screw at the fracture line.Adding an additional pin would share someof the loading with the screw but migrationcan be a problem.11 The techniquedescribed here and used by other surgeons(M. Glyde, personal communication) couldhelp in the prevention of screw breakagefollowing HCF treatment, and warrantsfurther investigation.

REFERENCES1. Marcellin-Little DJ, DeYoung DJ, Ferris KK,

Berry CM: Incomplete ossification of the humeralcondyle in spaniels. Vet Surg 1994;6:475-487.

2. Butterworth SJ, Innes JF: Incomplete humeralcondyle fractures in the dog. J Small Anim Pract2001;8:394-398.

3. Denny HR: Condylar fractures of the humerus inthe dog: a review of 133 cases. J Small AnimPract 1983;4:185-197.

4. Denny HR, Butterworth SJ: A Guide to Canineand Feline Orthopaedic Surgery. 4th edition.Oxford: Blackwell; 2000:352-357.

5. Glyde M, Connery N, Doyle R: Humeral condylarfractures in dogs. Irish Vet J 2003;3:158-165.

6. Murtagh K, Guerin S: Incomplete ossification ofthe humeral condyle in a Springer Spaniel. IrishVet J 2006;399-401.

7. Meyer-Lindberg A, Heinen V, Fehr M, Nolte I:Incomplete ossification of the humeral condyle asthe cause of lameness in dogs. Vet Comp OrthopTraumatol 2002;3:187-194.

8. Gordon WJ, Besancon MF, Conzemius MG,Miles KG, Kapatkin AS, Culp WTN: Frequencyof post traumatic osteoarthritis in dogs after repairof a humeral condylar fracture. Vet Comp OrthopTraumatol 2003;1:1-5.

9. Cook JL, Tomlinson JL, Read AL:Flouroscopically guided closed reduction andinternal fixation of fractures of the lateral portionof the humeral condyle; prospective clinical studyof the technique and results in ten dogs. Vet Surg1999;28:315-321.

10. Guille AP, Lewis DD, Anderson TP, ThompsonMS, Wheeler JL: Evaluation of surgical repair ofhumeral condylar fractures using self compress-ing orthofix pins in 23 dogs. Vet Surg2004;33:314-322.

11. Morshead D, Stambaugh JE: Kirschner wire fixa-tion of lateral humeral condylar fractures in smalldogs. Vet Surg 1984;13:1-5.

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