Surgical intervention is routinely recommended as the preferred treatment option for many patients following on from diagnosis of cruciate disease. Surgery allows for stabilisation of the stifle joint, with the hope of addressing pain, allowing return to function, and decreasing the progression of secondary degenerative joint disease (Shaw, 2017).
A vast number of surgical techniques have been pioneered to manage canine cruciate disease since the 1950s, including intracapsular, extracapsular and orthotomy procedures (von Pfeil et al, 2018). New techniques, or modifications of existing techniques (such as the modified Maquet procedure (MMP)) are continually being developed in this widely evolving field.
Three of the current most commonly performed surgical techniques - tibial plateau levelling osteotomy (TPLO), tibial tuberosity advancement (TTA) and lateral suture - will be described briefly, followed by techniques used to facilitate rehabilitation. During all three described procedures, the meniscus can be visualised, allowing for removal of any torn or damaged tissue, leaving in place any healthy tissue. Despite the fact that routinely removing or ‘releasing’ the medial meniscus prevents postoperative meniscal injury, current thinking is that this increases the progression of degenerative joint disease, and so is best left in place unless damaged (Davis, 2009).
TPLO
Osteotomy techniques such as the TPLO are performed with the goal of altering the joint biomechanics in order to stabilise the stifle joint. Radiographs are performed prior to surgery, and patients with a tibial plataeu of greater then 15° are suitable candidates for the TPLO procedure (Davis, 2009).
The technique itself involves incising the proximal tibia, rotating the tibia to create a less angled tibial plateau which is flatter and more level, then plating the site to secure it (Davidson et al, 2005). The aim of the surgery is to reduce the postoperative angle of the tibial plateau to between 1 and 9°. This eliminates the need to stabilise the stifle with extra-capsular techniques or by attempting to replace or ‘recreate’ the cruciate ligament (Davis, 2009), as it eliminates cranial thrust (the cranial movement of the femur relative to the tibia) (Harasen, 2011).
The most common complications following TPLO surgery include postoperative infection, implant failure, fracture of the tibial crest and patellar desmitis (Davidson et al, 2005).
TTA
The TTA procedure was introduced in 2004 as an alternative ‘less invasive’ surgical technique to manage cruciate ligament disease than the TPLO (Tuan and Farrell, 2015). The principle behind this technique is that the forces within the stifle are approximately parallel to those of the patellar tendon, and so shifting the insertion of the patellar tendon eliminates cranial tibial thrust (Davidson and Kerwin, 2014).
The surgical technique involves an osteotomy in the proximal tibia as per the TPLO procedure, but in the case of the TTA, the tibial tuberosity is advanced cranially. The advanced tuberosity is held in place with a titanium cage and a titanium bone plate, the latter being secured to the tuberosity by a fork, and tibia by bone screws (Proot, 2009).
Complications for TTA surgery are similar to those listed above for TPLO surgery (Tuan and Farrell, 2015).
Several studies have been conducted to compare the rate of complications for TPLO vs TTA. The results are variable, with some studies showing the TTA procedure to have a higher rate of meniscal injury post surgery (Tuan and Farrell, 2015), but a low rate of other post-operative complications such as implant failure (as the osteotomy incision is performed in the non-weight bearing portion of the tibia) (Proot, 2009), and therefore an overall reduced rate of complications (Tuan and Farrell, 2015). The most important statistic, in the author's opinion, is that long-term outcomes for both procedure are similar, with owners reporting a good or excellent outcome in over 90% of patients following either technique (Tuan and Farrell, 2015).
Lateral suture technique (extracapsular stabilisation)
This technique most commonly involves using a synthetic suture material passed around the lateral fabella, then through a hole drilled in the proximal tibial crest (outside the joint capsule) which provides immediate stability to the stifle (Harasen, 2011).
It is common for the prosthetic material to rupture several months following the procedure, by which point the joint remains stable as a result of periarticular fibrosis (Millis and Levine, 2014). Dependent on the go-ahead from the surgeon, it may be possible to initiate rehabilitation techniques following the lateral suture earlier than that of patients that have undergone TTA and TPLO procedures as there is no osteotomy site (Davidson et al, 2005).
Rehabilitation
Rehabilitation techniques are indicated following any type of cruciate surgery, and have been shown to benefit the patient by reducing postoperative pain and swelling, promoting healing and repair of tissues, improving joint range of motion and improving muscle strength and endurance (Marsolais et al, 2002). It has been demonstrated that early intervention with rehabilitation techniques increases muscle mass and stifle joint range of motion when measured 6 weeks postoperatively (Walker and Proot, 2009).
Rehabilitation techniques should be adapted on a case by case basis, and following the recommendation of the surgeon, as opinions on the optimum time to initiate rehabilitation may vary. The following describes examples of programmes given to otherwise healthy patients without complications.
Rehabilitation following cruciate surgery can be broken down into four phases.
Days 1–14 following surgery for all three surgical techniques
The goals for patients in the first fortnight following surgery are listed, followed by techniques which may be enlisted to achieve them: analgesia; wound management and management of postoperative swelling; maintaining joint range of motion using passive range of motion (PROM) exercises (Prydie and Hewitt, 2015).
- Postoperative analgesia is normally administered in the form of opiates for at least 24 hours following surgery, non steroidal anti-inflammatory drugs (NSAIDs) (Davis, 2009), and may also include local anaesthetic techniques.
- Pharmaceutical management of pain may also be supplemented with cryotherapy, which can be easily administered by wrapping a cold pack in a damp towel to allow conduction and applying this to the surgical site, or by administering a cryotherapy cuff. Cryotherapy also assists with postoperative swelling as application of cold results in vasoconstriction which assists in the control of tissue oedema, and slows enzyme activity, which in turn decreases the activity of the inflammatory pathways (Millis and Levine, 2014). To achieve this, a cold pack should be applied to the affected area for 10 minutes twice daily (Prydie and Hewitt, 2015).
- Electrotherapy can also assist with pain management, in the form of pulsed magnetic field therapy (PMFT) and LASER. Pulsed magnetic therapy consists of a coiled copper wire through which electrical currents are passed, creating a magnetic field. This interrupts the transfer of pain signals along nerve cells, with the result being an analgesic effect which has been demonstrated to assist in the management of both acute (Stocchero, 2015) and chronic pain (Ryang, 2013). Pads should be placed over the affected area for 15–20 minutes; and can be used up to every 4 hours in the immediate postoperative period.
- LASER therapy may also be applied to provide both analgesic and anti-inflammatory effects (Griffiths, 2014); and to promote healing. This is achieved via the delivery of photons of light at a cellular level, which trigger reactions within the mitochondria. Enzymatic production of adenosine triphosphate (ATP; the energy unit of the cell) is stimulated, increasing the speed of cell metabolism and function, including DNA production and healing and repair of the cell. ATP can also function as a neurotransmitter, altering pain modulation (Baxter and McDonough, 2007). LASER can be applied in the immediate postoperative period at a suggested rate of twice weekly, on the lateral aspect of the stifle for TPLO and TTA patients to avoid implants (Prydie and Hewitt, 2015).
- PROM to the joints of the digits, hock and hip for all patients (Prydie and Hewitt, 2015), and including the stifle for lateral suture patients (Davidson et al, 2005), promotes the maintenance of available joint range of motion, and so prevents stiffness, enhances proprioception and increases circulation (Marcellin-Little and Levine, 2015). This is best achieved with the patient lying comfortably and relaxed in lateral recumbency. The joints are moved passively by the therapist through their available range, in a slow, smooth fashion, until natural resistance is met. Starting distally with the digits and moving up through the tarsus then hip; each joint should be moved through three sets, twice daily, for maximum results (Carver, 2016).
- Exercise during the first 14 days following surgery should be restricted to no more than 5 minutes of lead exercise only (Shaw, 2017). Exercise which promotes stifle flexion such as jumping, stairs, free play with other dogs and therapeutic techniques including PROM to the stifle and use of cavaletti poles, should be avoided for TPLO and TTA patients during this period. This is to reduce the stress on the patellar tendon, and minimise the forces exerted by the quadriceps-patellar tendon and so reduce the risk of tibial crest avulsion and patellar desmitis (Davidson et al, 2005), two of the complications listed above.
- Before patients are discharged following any type of cruciate surgery, modification of the home environment should be discussed with owners. This should include use of non-slip runners if slippy floors could pose a risk to the patient, and use of ramps if the property is accessed via stairs. It may be necessary to restrict some patients to crate rest, or for owners to set up a suitable room, in order to avoid the activities described above which promote stifle flexion in order to minimise the risk of developing complications (Dorn, 2017). It may also be beneficial for owners to consider mental stimulation for dogs that are used to a large amount of exercise, which could include food puzzles, chew toys and supervised time out of the crate for social interaction; all of which can help minimise the stress brought on by change in routine (Dorn, 2017).
Weeks 2–6 following surgery
The goals for all patients during this phase of recovery include: continued analgesia (in the form of NSAIDs as required, supplemented with ongoing electrotherapy as described above); early weight bearing; beginning to strengthen the core muscles and atrophied hindlimb musculature:
- At 2 weeks post surgery, once the skin incision has healed, patients that have undergone extracapsular repair may be advanced gradually to include the exercises described both below and at stage 3. It is important to avoid very high impact exercise such as jumping until 12 weeks postoperatively, as this may lead to rupture of the synthetic suture material stabilising the joint (Davidson et al, 2005).
- At this stage for all patients, once the surgical incision site is healed, it is useful to introduce aquatic therapy in the form of underwater treadmill (UWTM) walking for 5–10 mins (Millis and Levine, 2014), once or twice weekly. For TPLO and TTA patients, initiating this type of therapy as the osteotomy site is still healing reduces stresses while encouraging early weight bearing, and begins to promote reversal of the muscle atrophy present in the affected limb. Bringing the water level above the level of the stifle promotes flexion and has been shown to increase joint range of motion (Monk et al, 2006).
- As well as continuing with PROM exercises as described above, additional exercises which should be included at this stage to encourage early loading include:
- Parastanding, placing one hind foot (first of the affected, then of the unaffected limb) on a raised surface such as a book for 30 seconds, twice daily (Figure 1)(Prydie and Hewitt, 2015)
- Rhythmical stabilisations, where the patient's body weight is pulsed on and off the hindlimbs by the therapist (Shaw, 2017) starting with 30 seconds, twice daily
- Exercise should be increased to 10 minutes of controlled lead exercise. Jumping, stairs and playing with other dogs should still be avoided at this stage (Prydie and Hewitt, 2015). Walking in circles and in figure-of-eight patterns will help enhance proprioception (Millis and Levine, 2014).
Weeks 6–12 following surgery
Postoperative radiographs are usually taken around the 6 weeks mark for TPLO and TTA patients, to ensure the osteotomy site has healed. This is important prior to commencing the therapeutic exercises descried.
Goals for this stage include: continued strengthening of the musculature of the affect hindlimb and core (Shaw, 2017); increasing the range of motion of the stifle joint, by continuing PROM until a full range is achieved (Walker and Proot, 2009):
- Rehabilitation in the form of aquatic therapy should be continued and the intensity gradually increased. This could be achieved by use of the UWTM, gradually increasing the length of the sessions and the speed of the belt; or by free swimming in a pool (Prydie and Hewitt, 2015). One study demonstrated that patients that had undergone 6 weeks of treadmill therapy post TPLO procedure showed no significant difference in muscle mass or stifle range of motion in the affected vs the non-affected limb (Monk et al, 2006).
- The following therapeutic exercises can be added in alongside those described above, to be performed twice daily:
- Sit to stand exercises, whereby the patient is asked to sit in a ‘tidy’ sit (with both stifles pointing forward) then rise to a stand position (Shaw, 2017). Starting with five repetitions and building up to 20
- Use of cavaletti poles, where the patient is walked over the poles 10–20 times to promote stifle flexion (Shaw, 2017)
- Stair climbing, the patient is walked up and down 5–10 stairs (Prydie and Hewitt, 2015)
- Use of wobble cushions under the hind feet, initially one foot, then both feet simultaneously to promote balance (Figure 2). This could also be achieved with use of a balance board (Davidson and Kerwin, 2014).
- Lead walking should be increased by 5 minutes per week until reaching 30 minutes twice daily, with the steady introduction of gradual inclines (Prydie and Hewitt, 2015).
12 weeks post surgery and beyond
Goals at this stage include a complete return to function. This goal should be achieved reintroducing the activities the dog practised prior to cruciate rupture. This may include:
- Increasing lead exercise to 30–45 minutes
- Introducing off-lead exercise, starting with 5–10 minutes and increasing gradually
- Introducing steep inclines
- Reintroducing play with other dogs, 5 minutes initially, building up slowly
- Reintroducing gentle ball games.
These activities should be introduced gradually, and on a one at a time basis (Prydie and Hewitt, 2015). Before the patient is signed off from rehabilitation, it would be valuable to discuss with the owners the importance of long-term care to help manage the development of degenerative joint disease. This could include weight management and the use of joint supplements and/or prescriptive diets based on recommendations from the veterinary practice.
Conclusion
In line with researched findings, rehabilitation techniques should be initiated soon after cruciate surgery in all patients in which the clinical situation allows, in order to improve stifle range of motion and muscle mass of the affected hindlimb, with the overall goal of a quicker return to function (Monk et al, 2006). Initiating some of these techniques in practice (for example, cryotherapy) will facilitate patient recovery, and discussing referral to a qualified rehabilitation therapist for techniques such as aquatic therapy, are vital roles the veterinary nurse can play in ensuring the best possible outcome for cruciate surgery patients. As outlined in article one, it is important to ensure the therapist is registered with an appropriate body such as RAMP, ACPAT, IRVAP or NAVP, and that there is excellent communication between all members of the multidisciplinary team to allow for the highest standards of care.
KEY POINTS
- The lateral suture technique, tibial plateau levelling osteotomy (TPLO), tibial tuberosity advancement (TTA) are three of the most commonly performed surgical procedures for addressing cruciate disease in the dog.
- Rehabilitation techniques are indicated following any form of surgical management.
- For the first 2 weeks following any type of cruciate surgery, the goals are: analgesia, management of the incision site and postoperative swelling, and maintaining joint range of motion.
- For weeks 2–6 the focus is on continued pain management, early weight bearing and strengthening.
- Goals for 6–12 weeks post operatively are to achieve a return to function for the patient through continued strengthening and range of motion techniques.