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15Joint 5 Dental Surgery Equipment & Instrumentation TRIPLE AND DOUBLE PELVIC OSTEOTOMY www.vetinst.com TPO had fallen out of favour with many surgeons because of a number of factors including the difficulty in diagnosing dogs early enough that degenerative changes are not already present, that results can be suboptimal if the envelope is pushed to include dogs that are borderline of the inclusion criteria, plus the improvements in outcome with total hip replacement providing preferable alternative options for many cases. Triple pelvic osteotomy (TPO) was described by Barclay Slocum in 1986 as a means to improve dorsal acetabular cover of the femoral head, reducing dorsal hip subluxation and damage to the dorsal acetabular rim. Performed early enough, TPO helps to mitigate progression of degenerative joint disease and maximises hip congruity and surgery is typically performed between five to eight months of age. Different methods can be used to assess the amount of correction required. Candidates should ideally have no evidence of osteo-arthritis and an intact dorsal acetabular rim (DAR). The quality of clunk when performing the Ortalani test gives an impression of the quality of the dorsal acetabular rim. When testing hip instability using the Ortalani test, suitable candidates should have angle of reduction not exceeding 30-35˚. Dorsal Acetabular Rim Skyline radiographs are used by some surgeons to better define the integrity of the DAR and to provide additional information for planning the extent of a correction. Recently, the procedure has been refined in an attempt to create a more stable construct with less post-operative implant failure problems. The advent of locking implants including locking TPO plates has improved construct stability and reduced complications such as implant loosening and screw pull-out. Performing a double pelvic osteotomy (DPO) where only the ilium and pubis are cut, and the ischium remains intact, is less de-stabilising to the pelvis than TPO. The technique was first described at ESVOT in 2006 following in-vitro studies by P. Haudiquet and J. Guillon and was followed by publication of a clinical case series by Aldo Vezzoni et al in VCOT in 2010. Assessing the angle of subluxationand reduction using the Ortalani Test In contrast to TPO, DPO creates quite a lot of tension in the pelvis as the acetabular segment is twisted outwards, an B6WfrFR6'&V7BV@b&FF6&R6VvrGVRFFRfVV6RbFW6RF'6f&6W2B27VvvW7FVBFB6'&V7FbFFF\E&PW&f&VB6rG2&R'F7V&ǒVgVvrFP7&V6VBf&6W2bEEffW27WGFrFRƗV66VBV&2Fg&VRFR6WF'V 6VvVBFR6WF'V"6VvVB2&FFVBfVG&ǒBFRƖ7FVFג2FVBFF&FF6'&V7FFRV&07FVFג&Rv&VBF&fR7F&ƗGFVvF22Bv0fW'ffV7FfRB2&vVǒ&VVG&VBࠤFW&VFFRF2FW&f&FfVBE""RVf07FVFגF22bv&WGvVVFREBFREvW&V'খ6WFR7FVFגbFR66VƖR2( 2ǒFRF'6666'FW27WBF2&VGV6W2FRF'6f&6W2W&VBEvFW@2V6FW7F&Ɨ6FbFRVf22Eࠥ67V7GREEFW2( 26r@6p6p7FWVBB֖֗6r77VW2&VFrFVf2'&vrFP&v67VFRv2FW6vVBf"2V6r67&Ww2vFF&VR67&WrֆW2VFW"6FRbFRƖ27FVFגB6PFR6VF'BbFRFRf"FRFFFb6W&6vRv&R@