TPLO/TTA - Cruciate Surgery

Most frequently cruciate changes will have been found from x-rays and limb manipulation prior to the day of surgery. Hopefully the images taken previously are appropriate for use but sometimes these may need to be repeated prior to surgery. If repeating the x-rays or x-raying to check for cruciate damage, try to use a radiographic reference ball as this will reduce the likelihood of measuring errors from rulers that may not be parallel to the x-ray plate or at the same height of the joint. 

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If taking x-rays prior to prepping the patient, be mindful of the patient's temperature and cover over any areas that are not being imaged with blankets to retain some heat as often x-ray tables can be cold.

 

Ensure the patient is on a heat pad with blankets and is pre-oxygenated prior to intubation. If it is a cat, make sure that they are given a full 30-90 seconds between giving Intubeaze and intubating to avoid risk of trachaeal irritation.

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 Once the patient is under general anaesthetic, the limb needs to be clipped and prepared for surgery. It is easiest to clip the limb with the patient in dorsal recumbancy, but you can still clip effectively with the patient in lateral recumbency with the limb being operated on, on top. The surgical clip will need to extend from just distal to the hock and up to the hip. Clip away the fur using size 40 blade clippers and clean the surgical site with your scrub of choice. A dedicated vacuum to remove fur from the surgical site prior to scrubbing is always useful. 

Wrap the patient's foot in a light bandage and this can then be suspended up in the air with a spare drip stand whilst the skin is prepped. Leave this bandage in place as often the surgeon will wrap the foot in sterile bandage material during the surgery in order to better manipulate the joint into position. 

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It can be useful to place a urinary catheter at this point too, espeically if it is due to be a long surgery and the patient is on fluids as we want to keep the patient as warm and dry as possible throughout and often they can urinate on themselves during anaesthesia. If the patient is due to be immobile for an extended amount of time after surgery, this is useful to be left in too, to prevent urine scalds.

 

Regional nerve blocks can then be performed to help reduce sensitivity to the stifle joint during surgery. Ideally these will be performed using a nerve locator but these are not available in every practice and the blocks can be done without, however care must be taken. Some surgeons prefer use of epidural blocks for cruciate surgery whereas others opt for local blocks of the femoral, sciatic, and obturator nerves. Bupivicaine works well as it has a long duration of action for this. A dose of 1mg/kg in canines and felines (do NOT exceed this dose in felines) is usually sufficient but this can be increased to 2mg/kg in canine patients if required. 

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Ensure that the patient has recieved analgesia prior to surgery starting, usually paracetamol (in canines only) at a higher dose is a good addition (10-20mg/kg slow IV). Often if they have struggled with cruciate injury for a while before surgery, they will already be on some analgesia at home, so be mindful of when last doses were given. If you are using a CRI, it is worth getting the loading dose on board at this point so that the CRI can get started and on board before surgery begins. I like fentanyl for orthopaedic procedures (loading dose of 2.5ug/kg slow IV followed by CRI of 2.5ug-10ug/kg/hr during anaesthesia), but be mindful that it is a respiratory depressant and can cause bradycardia, so IPPV and anticholinergics may be needed.

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Move the patient to the surgical table and postion where most appropriate for the surgery. If you have use of a vacuum mat, then these can be great to keep patients warm, supported, and stable throughout the surgery. Cruciate surgery can sometimes be over and done with quickly, especially with an experienced surgeon, but sometimes can be lengthy procedures, especially with larger patients, so I would always recommend using active warming devices such as Bair Huggers to keep them warm. It is advised to wait until the patient is fully draped before turning on forced air warming devices. Then give another scrub and prep the area using a final cleaning stage e.g. ChloraPrep. Often the leg will be suspended still until the surgeon has wrapped it in sterile material and can maneuvere it themselves, so I usually keep them tied onto the drip stand used during skin prep until they are draped.

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If there is a lot of kit, it can be useful to have a second person around to open the kit for the surgeon whilst you monitor the anaesthetic.

 

The surgeon can then perform the cruciate repair. If nerve blocks have been performed and are working well and are in conjunction with multimodal analgesia, then usually the surgery can go very smoothly. Occassionally if analgesic requirements are not fully met, the the patient can be more sensitive at particular points of the surgery such as during the stifle arthrotomy, so be mindful of any changes in heart rate, respiration rate, and blood pressure.

 

I would always make sure that your patient is on IV fluids throughout the surgery (surgical maintenance rate is 5ml/kg/hr in canines and 3ml/kg/hr in felines) to help with blood pressure and have bolus rates prepared and written down in case of a bleed.

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Hopefully the analgesic medications will already be on board and you should be able to have a smooth, pain free surgery. If the patient is on a CRI or has recieved high doses of analgesics, remember you may need a lower amount of anaesthetic gas to keep your patient asleep. Medications such as ketamine can have anaesthetic properties so be mindful of patient depth throughout. 

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If using antibiotics for the patient, check the frequency of when these should be given. Cefuroxime is commonly used in orthopaedic surgeries and is commonly given prior to incision and then at 90 minute intervals throughout until closure, but this should be confirmed with your surgeon.

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Remember to lubricate the eyes during surgery and on recovery to reduce risks of corneal ulcers forming. 

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After surgery, the surgeon will usually repeat the x-rays to ensure that the joint is in the correct position and that all of the screws and plates are in place. I usually place several inco sheets on the x-ray table to keep the patient warm and a large adhesive dressing over the surgical site to keep it clean whilst moving.

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In recovery, it is advised to continue the pain relief and wean the patient down it before stopping - this is especially important when using CRIs and can aid in a much more gentle recovery for them too.

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Careful post-operative nursing care of cruciate patients is important as it can have a huge impact on the patient's recovery and well being. Ideally ice pack the area for 15 minutes once out of surgery and repeat this every 4-6 hours. Be mindful that if the patient has had an effective nerve block, it may take some time before full sensation returns to the limb. Give the patient support when moving until they have full feeling back in the leg.