This blog will consider modalities commonly used by veterinary physiotherapists to improve the healing process after complications, and the overall recovery post stifle surgery in dogs.
In recent years, the application of Veterinary physiotherapy techniques after orthopaedic surgeries has increased. Veterinary surgeons are becoming more aware that surgery, along with its traditional protocols, may not on its own be enough to return the animals to normal function. Complications create further problems, and it is these that may be addressed with physiotherapy modalities.
There is considerable evidence which suggests that postoperative early vet physiotherapy following surgical complications after stifle surgery in dogs helps to decrease oedema and inflammation; encourages early weight bearing of the operated limb; prevents muscle wastage; increases stifle joint range of motions and; enhances balance and proprioception recovery.
Furthermore, it is suggested that the rehabilitation in dogs should commence on the first day after stifle surgery to achieve better outcomes and recovery rates (Davidson et al., 2005; Piermattei et al., 2006; Marsolais et al., 2002; Monk et al., 2006).
One of the problems identified with stifle surgery is that it creates joint stiffness. It is thought that massage may alleviate this by increasing the blood flow in the target tissue and reducing pain by manipulation of soft tissues using different pressure and strokes techniques. Furthermore, (Sharp, 2012b) in his clinical review stated that effleurage technique for 2-3 minutes in the early stage after fracture surgery (osteotomy of tibia in case of TPLO stifle surgery) is beneficial for swelling and inflammation reduction in an operated limb and also helps to control pain. This is supported by studies in humans using massage and there appears to be overall agreement that massage at an early stage after surgery can reduce oedema and pain as well as promote the improvement of range of motions. Even a brief massage of 5 minutes eases pain (Kim et al., 2015; Miller et al., 2015). This could prove beneficial in the post-surgery rehabilitation of dogs and therefore should be considered as a modality.
2. Therapeutic exercise
The use of therapeutic exercise during post-operative stifle surgery recovery appears to be beneficial in the first 6 months of the healing process as it helps to improve range of motion, decrease stiffness and pain and restore function.
Therapeutic exercise is usually prescribed as a part of a veterinary physiotherapy treatment protocol as well as the exercise performed in the home environment.
There are three studies describing different walking exercise timings after stifle surgery (Monk et al., 2006; Marsolais et al., 2002; Jerre, 2009) and these suggest that walking should begin immediately following stifle surgery.
Even though the cadence of walking that was used in each of these studies was different they all implemented a walk straight after surgery and the majority of dogs in all three studies returned to full functionality. Therefore, walking exercise is clearly beneficial for dogs in the early postoperative recovery after stifle surgery.
3. Cold (Cryotherapy)
After any surgery, inflammation, pain, haemorrhage and decrease of range of motion (ROM) can be detrimental whether this is in dogs or humans and cryotherapy is one way of addressing this. For example, (Bocobo et al., 1991) examined the effect of topical cooling on intra-articular temperature and found that the temperature of the intra-articular tissue was lower after only 5 minutes of topical cooling around the dog’s stifle joint. (Rooks et al., 1997) also recommended to apply cold packs for a period of 5 to 20 minutes after orthopaedic surgery or in rehabilitation to decrease muscle spasm and oedema. Moreover, (Lin, 2003) in his study on humans, showed that the use of a cold pack around the knee joint for 10 minutes has a significant effect on the range of motion of the knee joint - in particular on flexion. Furthermore, (Millis, 2004) recommended cryotherapy straight after surgery for 15 to 20 minutes during first 4 days and after exercise 2 to 4 times per day for 20 to 25 minutes during rehabilitation. It has been suggested to evaluate the cooling tissue after the first 5 minutes of the application as according to (Vannatta et al., 2004) timing of cooling may depend on tissue depths. In humans it has been reported that the use of cold treatment over a longer period results in pain reduction, increase of ROM and improvement in weight bearing (Martin et al., 2001).
In summary, the studies reviewed suggest that cryotherapy is beneficial to limb function in the acute post-surgery stage.
4. Heat (Thermotherapy)
Authors agree that heat increases the blood flow to the treated area which stimulates the metabolism and improves tissue elasticity while enhancing ROM through decreased stiffness in the stifle joint, providing relaxation and pain relief (Heinrichs, 2004; Sharp, 2008; Steiss and Levine, 2005).
(Millis, 2004) recommended the use of heat application in dogs around the joint after the acute inflammatory phase of tissue healing before exercising with the aim of reducing joint stiffness and increasing the elasticity of capsular structures.
5. Passive range of motion (PROM)
PROM is the full motion that the joint may be moved through with assistance. The benefits of PROM following stifle surgery in dogs are an increase of the blood flow to the area, lubrication of the joint by synovial liquid which brings nutrition to the joint, maintaining mobility, and reducing pain (Shumway, 2007).
It has long been recognised that immobilising the joint is detrimental to the mobility, Akeson et al., (1980) found that immobilization of the joint causes significant losses in lubrication by synovial liquid and increased collagen formation which in turn results in stiffness of the joint. In a different study, (NOYES et al., 1974) investigated the effect of immobility on the anterior cruciate ligament in primates where it was shown that after eight weeks of the joint disuse, the functional capacity of the ligament significantly reduced but after restarting exercises, it returned to near normal. However, ligament strength was only partially recovered.
By demonstrating the detrimental effects of immobilisation on joints these papers suggest that early movement is more beneficial than immobilisation in terms of overall joint health.
There are several studies that suggest that an early range of motion on the operated stifle joint in dogs increases the mobility, improve cartilage nutrition, strength of collagen fibres in the ligaments and reduces the process of osteoarthritis (Marsolais et al., 2002; Levine and DNb, 2014).
Furthermore, there are a number of studies on the effect of early motion in humans (Beynnon and Johnson, 1996; Glasgow et al., 1993; Shelbourne and Davis, 1999). These suggest that early PROM post-surgery is effective in reducing pain, joint effusion, minimising scar formation that limits joint movement, development of degenerative processes in joint and benefits in the increase of ROM, muscle mass and strength of the limb.
In summary, the studies reviewed demonstrated the benefits of passive range of motion exercise straight after surgery that enhance movement and the healing process in the joint. It should therefore be considered in early rehabilitation after stifle surgery in dogs.
6. Therapeutic Laser Therapy
Therapeutic lasers are used to accelerate the healing phases by reducing inflammation, oedema and pain, enhancing wound repair, soft tissue healing including existing scar tissue, bone fracture, and later assisting with osteoarthritis maintenance. Therefore, it can be concluded that it is a useful post-surgery protocol in dogs.
An in vivo study on rodents investigated the influence of infrared diode laser on bone healing, where scientists found that it increases deposition of collagen fibres and bone trabeculae which enhance the bone healing process (Mostafavinia et al., 2015). Although the sample size was small, scientists used a biomechanical bone evaluation method, which give us an idea about the mechanical strength of the bone. Further studies have to be undertaken on dogs to determine the right parameters of laser treatment for bone repair.
Another study established that the healing of an infected wound also depends on the wavelength. It was learnt that a wavelength of 630 nm associated with bacterial inhibition whilst using 810 nm wavelength stimulated the bacteria to grow. As a result, it is important to be aware of this when treating wounds.
Further studies on rodents demonstrated that use of low-level laser therapy (LLLT) plays an essential role in the treatment of wounds in early stage (Medrado et al., 2003; Trelles et al., 1989). For example, (Trelles et al., 1989) scrutinized the action of LLLT on mouse tongue mast cells. It demonstrated an increase of histamine and vasodilation which increased the biological process of mast cells following irradiation of the tongue with a single application of LLLT.
Another randomised study in humans suggested that LLLT reduces pain and disability in knee osteoarthritis cases and the desirable dose per treatment was 4-8 J with 785-860 nm wavelength and 1-3 J with 904 nm wavelength (Stausholm et al., 2019).
In conclusion, there is evidence to support the early clinical use of laser therapy in humans and rodents to treat many conditions. However, further studies are required to determine the benefits use of this modality in dogs, in particular in the early stage after surgery.
7. Therapeutic ultrasound (TU)
Ultrasound (US) refers to high-frequency acoustic waves above human hearing. The benefits of US are the production of heating in deep tissues and short duration of application.
Authors agree that ultrasound enhances protein production, collagen synthesis and fracture healing, and also influences the bone ingrowth response and the scar tissue structure by increasing scar mobility and its tensile strength later in remodeling stage (Heremans et al., 2017; Millis and Levine, 2013; Ganzorig et al., 2015; Gan et al., 1995; Tanzer et al., 2001; Claes and Willie, 2007; Mosselmans et al., 2017; Enwemeka, 1989; Ramirez et al., 1997; Fisher et al., 2003). Therefore, the usefulness of this modality in the early stage of canine rehabilitation can be demonstrated.
It was believed that high doses of ultrasound could delay callus formation and calcification, as a result causing damage to subperiosteal of the bone and late fracture healing (Watson, 2008; Millis and Levine, 2013). However, it has later been demonstrated that ultrasound can stimulate physiological processes, for example bone healing, without thermal effect. Heremans et al., (2017) in their case study demonstrated on radiographs that the use of therapeutic ultrasound (TU) after TTA surgery (metal implants are placed to stabilise the bone) in a dog that developed a fracture two weeks after the operation can influence its healing by increasing circulation and callus formation.
The use of US over metal implants (for example after TPLO or TTA surgery to treat fracture) is still controversial, with some authors recommending precautions (Watson, 2008; Steiss and McCauley, 2004; Andrades et al., 2014), whereas others state that there are no problems (Kocaoğlu et al., 2011; Ustun et al., 2008).
Previously, (Lehmann et al., 1958; Skoubo-Kristensen and Sommer, 1982) suggested that the use of US over metal plate is a potential cause of excessive local heat which may then cause necrosis of surrounding tissues and could lead to implant loosening. Andrades et al., (2014) in their study applied therapeutic ultrasound (TU) in continuous mode with 1 and 3 MHz frequencies and 1 and 2 W/cm2 intensities for two minutes around the metal plate in the femur of canine cadavers. They discovered this application produced heating of the metal plate and surrounding tissues and concluded that use of TU at 1-3 MHz frequency requires caution in the presence of a metal plate. The limitations of the study were the low number of cadavers. In addition, factors such as the absence of blood flow and the process of freezing and reheating the samples could have affected the temperatures measured. Therefore, further studies on live animals would be beneficial to assess the effect of the heat produced by TU on bone and surrounding tissues over the metal plate.
In contrast, Kocaoglu et al., (2011) in their study on the use of TU in continuous wave form around metal plates in 40 live rats with a dose of 1W/cm2 for 5 minutes daily for 27 days, discovered that the heating effect of US in the presence of metal in bone did not cause tissue necrosis and no implant loosening was observed. Interestingly, this study did not find a significant difference in callus formation between the treated group with ultrasound application and controls. These findings conclude that the heating effect of TU did not harm the tissue containing the metal implant but also did not make a difference in callus formation.
Furthermore, low-intensity pulsed ultrasound (LIPU) demonstrates a positive effect on bone regeneration and osseointegration around dental implants in early stage healing in humans (Ustun et al., 2008). For example, (Tanzer et al., 2001; Ganzorig et al., 2015) demonstrated that in ultrasound stimulated implants, the bone ingrowth was an average of 119% more compared with the contralateral controls. This result has great benefits in orthopaedics and orthodontics because it can allow early fixation during bone healing. Despite this result, the mechanism by which LIPU was able to substantially influence the bone ingrowth response remains unknown and so further studies to assess its effect are needed.
In conclusion, the facts that ultrasound in widely used in orthopaedics and orthodontics in humans and that the use of LIPU over metal plates is beneficial for bone healing cannot be ignored. Heremans et al., (2017) have already demonstrated the benefits of US on bone around metal implants. This suggests that this might be beneficial after stifle surgery in the canine population.
8. Pulsed electromagnetic field (PEMF)
PEMF is a form of inductive therapy which uses the power of a pulsed magnetic field to promote tissue repair and influence cell activity. The use of PEMF in the postoperative period can significantly reduce the pain and inflammation effect. Fini et al., (2005) found that the therapeutic effect of PEMF on articular hyaline cartilage stabilises the progression of osteoarthritis (which is common after stifle surgery (Boyd et al., 2007; Hurley et al., 2007)). It has been suggested that PEMF stimulation could be a promising chondroprotective therapy for osteoarthritis because of the influence on the chondrocyte metabolism of enhancing cartilage and subchondral tissue production (Fini et al., 2005).
Early treatment over 6 months with PEMF in humans is suggested to dramatically reduce pain by 75% and necrosis development by 85% (Muccioli et al., 2013). It was concluded that PEMF can play an important role in treating pain and necrosis of the human knee by conservative treatment in early-stages, which will prevent further complications and the need for later surgery. The fact that this is so efficacious in humans raises the question of why this is not used more in dogs.