Proceedings of the World Small Animal Veterinary Association Sydney, Australia 2007

Transcription

1 Proceedings of the World Small Animal Veterinary Association Sydney, Australia 2007 Hosted by: Australian Small Animal Veterinary Association (ASAVA) Australian Small Animal Veterinary Association (ASAVA) Australian Small Animal Veterinary Association (ASAVA) Next WSAVA Congress

2 POST-OPERATIVE MANAGEMENT FOLLOWING FRACTURE AND INTRA- ARTICULAR SURGERY Warrick J. Bruce BVSc (dist), MVM, DSAS(orthopaedics), MACVSc Veterinary specialist Orthopaedic Services, P.O. Box 14115, Hamilton, New Zealand Introduction: Appropriate post-operative management following fracture and joint surgery is critical for success and can be as important in determining the outcome of the case as the surgery itself. In general, post-operative management should be directed at allowing early pain-free controlled mobilization of the limb in order to prevent fracture disease (i.e. joint stiffness, osteoporosis, muscle atrophy or contraction) as well as the prevention of complications such as infection, soft tissue injuries and bone destabilization. This lecture is intended to be a practical outline of my post-operative management strategies. I am not a veterinary physiotherapist and therefore do not have access to elaborate physical therapy equipment or techniques but hope to present a basic approach that would be applicable to all general practitioners. Post-operative antibiotics: The prophylactic administration of peri-operative antibiotics for orthopaedic procedures should be reserved for procedures expected to last more than 90 minutes in duration, open contaminated fractures, or where there is anticipated blood pooling and haematoma formation. The implanting of orthopaedic implants is not in itself an indication for prophylactic antibiotic treatment unless the patient is immunocompromised, where there is sparse soft tissue coverage of the implants, or if an infection would be disastrous to the surgical procedure (e.g. total hip replacement). Peri-operative antibiotics are given intravenously at induction. With very long or high-risk procedures, additional doses are given at frequencies depending on the drug s MIC and half-life for up to 24 hours postoperatively. Antibiotic treatment for longer than 24 hours post-operatively has not been shown to reduce infection rates and may perpetuate bacterial resistance. NOTE: The use of prophylactic antibiotics is no substitute for strict asepsis and good surgical technique. A standard protocol I use is: Intravenous cephazolin 22mg/kg IV) or amoxicillin-clavulonate (Augmentin 20 mg/kg IV) is administered no less than 30 minutes before skin incision. The drug is administered every 90 minutes whilst the incision is open. High risk procedures might warrant additional IM or IV doses at 6 to 8 hour intervals for 24 hours.

3 Analgesia: Perhaps the greatest leap in our understanding of pain management has been the acknowledgement that pre-emptive pain relief provides superior postoperative analgesia than post-operative treatment alone. Studies in humans have demonstrated lower patient morbidity, lower mortality, and more rapid recovery rates when patients are given pain relief before a painful procedure is performed. All animals undergoing orthopaedic surgery at my clinic are given morphine (0.5 mg/kg IM) as part of their anaesthetic pre-medications. Repeat doses of morphine are given every 3 to 5 hours as required during the day of surgery. Buprenorphine (Temgesic, 0.01 to 0.02 mg/kg IM), a longer acting partial muopioid agonist / antagonist, is usually given late in the evening of the day of surgery (at least 4 hours after the last morphine treatment) to provide pain relief throughout the night. In cases of joint surgery, a local joint block can be employed to give up to 24 hours of pain relief. Bupivicaine (Marcain 0.5%, 2mg/kg) is injected into the joint following flushing and closure of the capsule. Some drug leaks into the periarticular tissue but this is left in situ to provide additional pain relief. Also, in the case of articular fractures or tibial plateau leveling procedures, some local anaesthetic can be instilled over the fracture / osteotomy sites prior to closure. Intra-articular morphine (0.1mg/kg diluted in saline to a volume of 0.1ml/kg) has also been used with good effect as have combinations of bupivicaine and morphine (Sammarco et al 1996). Epidural administration of 0.5% bupivicaine (0.22 ml/kg) and/or morphine (0.1 mg/kg) at induction can provide profound hind limb analgesia post-operatively for up to 24 hours (Hendrix et al 1996). I tend to reserve this form of analgesia for the more severely painful trauma cases such as spinal, pelvic and highly comminuted hind limb fractures. Painful forelimb procedures, particularly those distal to the elbow, can receive up to 4 to 6 hours of analgesia from a brachial plexus local block with bupivicaine (Quant and Rawlings 1996). Non-steroidal anti-inflammatory drugs (NSAIDs) e.g. meloxicam (0.2 mg/kg SC) or carprofen (4mg/kg SC) are administered by injection on recovery from the anaesthetic. In dogs, I continue oral NSAID therapy for 2 weeks post-operatively 0.1mg/kg sid or 2mg/kg bid for 7 days then 2mg/kg sid for 7days). Care must be taken in the administration of NSAIDs to cats. I use an injectable loading dose of 0.2mg/kg post-operatively and then oral 0.1mg/kg sid for up to 4 days. The dose rate is reduced to 0.1mg/cat/day if longer treatment is required. The surgical incision: I like to cover all surgical wounds with a dressing, particularly when the wound is on a limb or in the pelvic area and likely to come in contact with the ground when

4 the animal is resting. Surgical incisions are covered with a peripherally adhesive, semi-occlusive, non-adherent dressing (e.g. Melolin, Smith & Nephew) dressing plus Hypafix (BSN Medical) adhesive or a Primipore dressing (Smith & Nephew). Using an aerosol vapour permeable spay dressing (e.g. Opsite, Smith & Nephew) will provide an additional protective barrier to the wound and will greatly improve the stick of the dressing. I tend to leave the dressings in place for 3 to 5 days but generally they are not necessary after 24 hours because fibrin seals the wound and provides an adequate barrier to the environment. Bandaging: In dogs having procedures involving the elbow or stifle or more distal areas of the limb, I find the application of a well-padded Robert Jones Bandage (RJB) useful in reducing post-operative oedema and pain and I use them routinely. However, these bandages must be applied correctly and owners must be instructed on their care, as a poorly managed bandage will cause more problems than they are worth. The limb should be bandaged in its normal standing angle. A common mistake is to bandage the limb in extension, which effectively lengthens the limb and makes it extremely uncomfortable for the patient. With more proximal conditions, the bandage must extend up into the axilla and groin area and distal stirrups should be used to prevent migration of the bandage. It must be wellpadded and not too tight nor too loose. An over-tight bandage, or poorly compressed bandage, will result in focal compression which can cause embarrassing skin necrosis and pressure sores! I recommend hind limbs are supported in a RJB for no longer than 4 to 5 days -the incidence of bandage related soft tissue injuries will increase significantly if it applied for longer periods. Many cats do not tolerate RJBs on their hind limbs particularly well and I tend not to use them in this species. Chondroprotective drugs: I encourage the use of pentosan polysulphate (Cartrophen-Vet, Pentosan SC) injections from around 10 days post-operatively in all cases of joint surgery. I believe this drug alleviates the signs of osteoarthritis and also facilitates the repair of joint structures post-operatively, although there is sparse information in the literature on the beneficial effects of PPS following joint surgery. Weekly treatments given by injection for four weeks provide an ideal opportunity to assess the operated limb and monitor post-operative progress. Physiotherapy: Physiotherapy in the form of cold therapy can begin the day after surgery to help reduce swelling and pain. The old bag of frozen peas has been replaced by a variety of more modern gel-like products that retain cold (or heat). Cold therapy should be applied for 10 to 15 minutes bid or tid. When treating marked oedema, cold therapy can be applied on alternate 30 minute intervals on the day of injury. On the following day, it may be more effective to alternate cold with heat therapy to cause constriction and dilation of vessels to aid venous and lymphatic return.

5 Heat therapy begins from 48 hours after surgery or on the day of RJB removal. Owners are instructed to apply heat therapy to the area for 10 to 15 minutes twice daily. A wheatie bag, which has been warmed (together with a glass of water) in a microwave oven, is an excellent way of applying heat. Alternatively, gamgee bandages or cotton wool can be immersed in hot water and wrung out and carefully applied. Hand massage of the distal limb is performed at this time to improve circulation flow and reduce oedema. Some owners like to use herbal rubs such as Aloe Vera or Arnica and these can be massaged over areas of bruising and swelling at this time. I encourage heat treatment and massage for 2 to 3 days or longer if required. Passive range-of-motion (PROM) exercises can begin from day 1 postoperatively or on the day of bandage removal. Ideally, all joints of the affected limb should receive PROM exercises 2 to 3 times a day. During each session, a minimum of 10 flexions and extensions should be performed on each joint. After flexion and extension of the individual joints, the entire limb should be cycled through its full, pain-free range-of-motion 10 times. Stifle movement should be slow and gentle initially. The owner should be instructed never to force the joint or cause pain, but gently maneuver the limb through a range-of-motion that is well tolerated. PROM exercises are encouraged for the first 4 weeks after surgery. Exercise: 0 to 8 weeks post-op Orthopaedic patients must have enforced rest for the first three to eight weeks (depending on age and procedure) to allow for optimal healing. In the dog, exercise is usually limited to short leash walks for toileting purposes. Weight shift exercises are a good safe way to encourage controlled loading of the operated limb and can begin almost immediately. When standing, the patient is supported by the handler and encouraged to shift its weight onto the affected limb for 5 seconds. The weight shift exercise is repeated 5 times bid and this can be slowly increased to reps of 10 times tid with healing. A more advanced form of this exercise is for the handler to manually unload the unaffected limb, by lifting and abducting it, to force the patient to redistribute its entire weight. Stepup / step-down exercises are also easy do during toileting walks. The dog is walked over a low level object such as a book so that it steps up onto its affected limb. Start with a book 10mm in height (10 reps per walk) and build up to a height of 50mm over a six week period.

6 6 to 8 weeks post-op Most fractures are radiographically reassessed around this time or earlier, in the case of immature patients. Controlled exercise on a leash may begin once there are radiographic signs of fracture healing. Leash walks should be minimal at first (15 to 20 minutes once daily), and then gradually increased to twice daily after 8 weeks post-operatively. Slight incline walking (slowly up and down small hills) can also begin and figure-of-eight maneuvers are useful to develop limb proprioception and abductor / adductor strength. Sit / stand exercises help strengthen hip and stifle muscles and are excellent therapy following femoral fracture and cruciate surgery to build thigh muscle mass. I start these exercises around 6 weeks post-operatively. Whilst walking on a leash the dog is commanded to sit and just before he fully assumes the sitting position, he is commanded to walk-on. This routine is repeated 10 or more times every walk. 8 to 12 weeks post-op Between 8 and 12 weeks, the duration of leash walking exercise can be increased slowly by 10 to 15 minutes per week as we hopefully are now entering the phase of reconditioning. The emphasis is now placed on more incline work and tighter figure-of-eight maneuvers during the exercise periods. Deep-water swimming for 10 to 15 minutes several times a week, if possible, is excellent therapy at this stage. References: Sammarco, J.L., Conzemius, M.G., Perkowski, S.Z. et al. (1996) Postoperative analgesia for stifle surgery: a comparison of intra-articular bupivicaine, morphine, or saline. Veterinary Surgery 25, Hendrix, P.K., Raffe, M.R., Robinson, E.P. et al (1996) Epidural administration of bupivicaine, morphine, or their combination for postoperative analgesia in dogs. Journal of the American Veterinary Medical Association 209, Quant, J.E., Rawlings, C.R. (1996) Reducing postoperative pain for dogs: Local anaesthetic and analgesic techniques. Compendium for Continuing Education 18: Further reading: Millis, D.L., Levine, D., Taylor, R.A. Canine Rehabilitation and Physical Therapy Elsevier, St Louis, Missouri