PERIOPERATIVE CARE

Perioperative analgesia strategies should be both preemptive and multimodal. These strategies may include using systemic opioids such as morphine, nonsteroidal anti-inflammatory drugs (NSAIDs) such as carprofen, epidural opioids and local anesthetics such as morphine and bupivacaine, and N-methyl-D-aspartate receptor blockade agents such as ketamine at a continuous-rate infusion. Postoperative analgesia strategies may include oral administration of NSAIDs, opioids, or both and often will be tapered over two weeks.

Prophylactic use of cefazolin is recommended at a dose of 22 mg/kg administered intravenously 30 minutes before surgery and then every one-and-a-half to three hours during surgery thereafter. Assuming no breaks in sterile technique occur, cefazolin doses are repeated every eight hours during the first 24 hours after surgery. Little scientific support exists for the common practice of administering antimicrobials for several days postoperatively. Most patients that do not have complications are discharged from the hospital the day after surgery.

Recovery from a TPLO consists of three stages: 1) incisional healing, 2) bone healing, and 3) physical rehabilitation. During the two-week incisional healing, it is imperative that the pet not be permitted to lick or chew at the incision because incisional dehiscence may increase the risk of osteomyelitis. An appropriate protective bandage, restraint collar, or both are recommended to prevent self-mutilation. It has been stated that fracture and osteotomy healing represents a race between bone healing and fixation failure. To this end, during the bone healing stage (usually eight to 12 weeks), patients should not be permitted to run, jump, or have free access to the yard, furniture, stairs, slippery floors, or other pets. Confinement to a small space with good footing and minimal external stimuli is advised when the patient is unsupervised (a large crate placed in a quiet room of the house works nicely). Short walks at a slow pace on a short leash several times a day are encouraged. Sling support of the hindquarters may be indicated in patients with multilimb disability, patients with poor strength or balance, and patients traversing slippery surfaces or steps. Typically, several weeks after surgery, the pet will feel rambunctious as limb function and comfort improve. This is an important time to remind pet owners that the bone is not yet healed.

Bone healing is monitored radiographically in four- to eight-week intervals until bony union is documented. Once bone healing is documented, then slow and methodical increases in activity can be instituted as part of the physical rehabilitation. This begins with increasing the length of leash walks each week, progressing to increased time off leash but under supervision. Anecdotally, too vigorous or too rapid a pursuit of reconditioning increases the risk of patellar desmitis. Physical rehabilitation improved the outcomes of patients treated with extracapsular stifle stabilization more than did surgery alone.¹⁸ Various protocols for physical rehabilitation are practiced for TPLO, but their benefits and risks have not been objectively identified. Empirically, carefully instituted physical rehabilitation by a trained therapist appears to hasten the recovery of limb use.

INTRAOPERATIVE AND POSTOPERATIVE COMPLICATIONS

A wide variety of complications have been reported for the TPLO.^14-16 Intraoperative complications of extreme hemorrhage and intra-articular placement of screws or jig pins can be avoided with keen attention to detail. Hemorrhage from the popliteal vessels can be profuse. Familiarity with the cross-sectional anatomy of the proximal tibia and surrounding soft tissues helps prevent errant passage of the periosteal elevator, drill bits, taps, screws, and jig pins. Soft tissue complications in the postoperative period include seroma or hematoma, dehiscence, infection, and irritation from bandaging.