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Treatment of humeral intracondylar fissure (HIF) with 32mm compression screw and DBM
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Stanley Sheldrake2
Stanley Sheldrake1

Incomplete ossification of the humeral condyle (IOHC) and humeral intra-condylar fissure (HIF) are often used interchangeably.

HIF has been demonstrated to develop in a previously unaffected elbow (Farrel). IOHC was initially described condition as a failure ossification of the intra-condylar physis does in predisposed breeds, notably the Springer Spaniel.

The Problem:

HIF was first described by Meyer-Lindenberg in 2002. While several theories have been proposed the cause for this condition is unknown. Transcondylar lag screws can be used to prevent fracture and treat lameness in dogs with HIF.

However, one of the main complications in these cases managed surgically is implant failure due to a few factors:

  • The bone either side of the fissure tends to be sclerotic and does not heal.
  • The very short fracture gap results in a high strain environment on the implant.
  • These are often young, active dogs resulting in the implant potentially being subjected to these forces for years.

The novel screw system described here is designed to achieve compression through different pitches of the cis and trans thread, whilst having a central thread-less section that is recessed from the bone tunnel providing a space for the insertion of DBM. The design promotes compression of teh medial and lateral components of the condyle while the use of DBM promotes osteo-induction through bone morphogenetic proteins to encourage new cancellous bone formation in the void around the shaft screw and redcues cyclical stress of the implant.

Case presentation:

The patient was a two and a half year-old male entire Springer Spaniel with right fore lameness. The lameness localised to the elbow on clinical exam.

The dog had previously been treatment for left fore lameness with a transcondylar 4.5mm cortical screw, which failed two years after placement.

Diagnosis:

Due to the fissure lines in HIF often being oblique to the sagittal plane radiography has a low sensitivity in detecting lesions since it relies on the fissure lining up with the x-ray beam. Computed tomography is the recommended diagnostic modality for identifying HIF in dogs (Rovesti et al 2002) and was performed in this case, via an out-patient CT service. This identified the presence of a HIF lesion.

Surgery:

The affected limb was clipped and surgically prepared, a local anaesthetic RUM block was applied using 0.5% Marcaine.

A bilateral approach was made to the humeral condyle. Medially care was taken to avoid the ulnar nerve caudally and the median nerve and arteries cranio-medially. Laterally the radial nerve was identified and avoided. Once the medial epicondyle was exposed via sharp dissection the pre-measured insertion point for the drill bit was identified using calculations outlined in Barnes, Morris and Anderson’s paper (2013).

The site was pre-drilled with a 1.8mm drill bit aiming for the marked site on the lateral condyle. Following this the specific 'VTB (Veterinary Tissue Bank) IOHC screw' drill bit was inserted and followed the guide line. Following lavage of the hole with saline the 32mm stepped screw was advanced until the recessed central section was almost buried. At this point the demineralised bone matrix (DBM) putty was injected into the void before tightening the screw until the flush with the near (cis) cortex.

References:

Barnes, D, Morris, A, & Anderson, A n.d., 'Defining a Safe Corridor for Transcondylar Screw Insertion Across the Canine Humeral Condyle: A Comparison of Medial and Lateral Surgical Approaches'(2013), Veterinary Surgery, 43, 8, pp. 1020-1031, Science Citation Index, EBSCOhost, viewed 28 July 2017.

Meyer-Lindenberg, A, Heinen, V, Fehr, M, & Nolte, I 2002, 'Incomplete ossification of the humeral condyle as the cause of lameness in dogs', Veterinary And Comparative Orthopaedics And Traumatology, 15, 3, pp. 187-194, Science Citation Index, EBSCOhost, viewed 28 July 2017

Rovesti, G, Biasibetti, M, Schumacher, A, & Fabiani, M 2002, 'The use of the computed tomography in the diagnostic protocol of the elbow in the dog: 24 Joints', Veterinary And Comparative Orthopaedics And Traumatology, 15, 1, p. 35-43, Scopus®, EBSCOhost, viewed 27 July 2017.

Sullivan, M, Carrera, I, & Hammond, G 2008, 'Computed tomographic features of incomplete ossification of the canine humeral condyle', Veterinary Surgery, 37, 3, p. 226-231, Scopus®, EBSCOhost, viewed 28 July 2017.

AlisonLead Vet. Summerlane Veterinary Centre
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