Small Ani. Sx- Ortho- Conditions of the Hip Joint 2

drraythe's version from 2016-04-29 14:49

Sx tx of Hip Dysplasia

Question Answer
Sx tx of HD can be in three catgories- what are these?Preventive, Palliative, Substitutive
what are the 2 PREVENTATIVE SX PROCEDURE you can do for HD?Juvenile pubic symphysiodesis (JPS), Triple pelvic osteotomy (TPO)
WHEN do you do Juvenile pubic symphysiodesis, and at what age should you do this? what do you do?Do this BEFORE THE DJD SETS IN, when they are young (Preventive procedure) **< 20 weeks of age. (needs to be super young bc need to still grow a lot to cause the deformity we want) Basically you are causing a growth deformity by causing Premature pubic physeal closure with electrocautery. This results in Increased dorsal acetabular coverage (*careful of urethra) (said in class: if you wanna work ethically, you should neuter at the same time bc they have no CS but carry bad genetics)
WHEN do you do Triple pelvic Osteotomy (TPO)? at what age? What do you do? Do this BEFORE THE DJD SETS IN (only if laxity/sublux, if already arthrosis, then it will progress regardless), when they are young (Preventive procedure) **Young dogs (less 8 months) BEFORE THEY HAVE DJD! you basically Increase dorsal acetabular coverage by making 3 cuts, ilium, pubis and ischium, so have free acetabular fragment Then twist it a bit to inc dorsal acetabular coverage and fix it in place there BEFORE AND AFTER:
what are the 2 PALLIATIVE sx options for tx of HD?(1) Pectineomyectomy, Iliopsoas tenotomy and Neurectomy of joint capsule (PIN) (2) Femoral Head & Neck Ostectomy (FHO)
what is the PIN procedure, when do you do it?This is a PALLIATIVE procedure (removaing pain caused by HD- pain from too much tension on joint capsule. so release tension causing things and kill the nerve) You perform a Pectineomyectomy, Iliopsoas tenotomy and Neurectomy of joint capsule (PIN). (-->neurrectomy)
what is the FHO procedure? when do you do this? How do you do this?This is a SALVAGE/palliative procedure-- can use this for HD/ Coxarthrosis, Fractures, and Legg Calvé Perthes dz. "Femoral Head & Neck Ostectomy". Basically cut a line between trochanter major & minor and provide Postoperative physiotherapy (how much physiotherapy might dictate how much ROM you get back)
Total Hip Replacement--> what are you doing here, what is the outcome?Replace a dysfunctional hip joint and get a Pain-free, well functioning limb
what are the three components of the total hip replacement?(1) Acetabular cup (UHMWPE (ultra high molecular weight polyethylene)± Metal cup) (2) Head/Neck (3) femoral stem
what are the two methods of fixation for a total hip replacement?Cemented (stabilized by PMMA= bone cement), and Cementless (Bone Ingrowth is what stabilizes it)
pros and cons to cemented?PRO: easy to do, dont need material that is super biocompatible (no metal cap). CON: burn bone as it hardens, these eventually loosen over time, esp in a puppy that is jumping around a whole ton. (Aseptic loosening). Revisions difficult (bc youre working around a clump of cement) and there is a risk of infection
Explain how cementless total hip replacements workyou put contact between the bone and the implant, implant is biocompatible metal with a roughened surface which allows bone ingrowth--> this provides DEFInitiVE fixation.
what is a Universal THR?Combine cemented and cementless- Cementless cup + Cemented stem
what do you do Stress shielding with a total hip replacement?make sure shaft of femur part is far down into bone to shield it from stresses from walking (redistribution of stress with femoral component)
3 Principles of fixation for Zurich CementlessTHR (Cementless modular system)Anchored to medial cortex, locking screws, Bone ongrowth
for Zurich Cementless THR (Cementless modular system), why screws on the MEDIAL side?forces acting on it--> tension there--> bone prolif
what is a "press fit" in a total hip replacement? best indicated for?little holes, bone grows into holes to provide fixation. Good for young dogs.
some remarks on sx technique for a total hip replacementCRAZY STERILE BRO. cover everything, 2-3 pairs of gloves. Clean up femoral cavity to make sure for implant. DONT LEAVE ANY CARTiLAGE OR SCLERotic BONE--> there is no blood supply!!
post-op management of total hip replacement?Discharged one day after surgery (as long as they can put weight on all 4 legs)! 6 weeks confinement, 4 months to full activity
prognosis of total hip replacement?really good! Successful outcome (22 months): 97% (About 10-15% revision surgery-- main reason for failure is infection)
common complications of total hip replacement?Luxation, Femoral fracture, Loose implants, Implant failure, Infection