Anterior cruciate ligament rupture in dogs

• Etiology of ACL rupture in dogs
• Clinical signs of ACL rupture in dogs
• Diagnosis of anterior cruciate ligament rupture in dogs
• Treatment of cruciate ligament rupture in dogs
• Prognosis for ACL rupture in dogs
• Clinical case No. 1
• Clinical case No. 2
• Clinical case No. 3
• Clinical case No. 4
• Clinical case No. 5

Anterior cruciate ligament rupture is a common problem in various dog breeds resulting in pelvic limb lameness due to pain and instability in the stifle joint. In the future, this pathology will lead to the development of a chronic inflammatory process and osteoarthritis, as a result of which the dog will lose the ability to fully use its paw.

Anterior cruciate ligament rupture often occurs in large and medium-sized dog breeds: Rottweiler, Caucasian Shepherd, Canecorso, Labrador, Boxer and others. In our veterinary practice, it is also not uncommon to see ruptures of the anterior cruciate ligament in small breeds of dogs, such as Yorkshire terriers, miniature poodles, pugs and chihuahuas. In extremely rare cases, this pathology occurs in cats and, as a rule, has a traumatic origin.

The age of dogs can vary. This is due to the cause of this pathology, but most often dogs from 5 to 7 years old suffer from ACL rupture.

Rupture of the anterior cruciate ligament in dogs accounts for 60-70% of the total number of pathologies of the knee joint.

To better understand the cause of an ACL tear, the mechanism of the tear itself, and its consequences, you need to have a good understanding of the anatomy of the knee joint.

The knee joint includes the distal epiphyses of the femur, the patella, the proximal epiphyses of the tibia and fibula and respectively consists of the femur joint, the patella joint and the proximal intertibia joint.

The knee joint in a dog is a complex uniaxial joint, since movement in this joint is possible in the lateral sagittal plane.

The femoral joint is formed by the femur and the kneecap. The lateral and medial holders of the patella originate in the ligamentous tuberosities of the femoral condyles and end on the kneecaps. The straight ligament of the patella starts from the apex of the patella and ends at the crest of the tibia.

The femur joint is a complex joint. In addition to the femur and tibia, it includes the lateral and medial menisci, which are involved in smoothing the incongruent articular surfaces. The menisci have a semilunar shape and each of them is connected to the tibia - the cranial and caudal tibiomeniscal ligaments. The lateral meniscus also has a femoral meniscus ligament.

The lateral and medial sesamoid bones (vesalian bones) are located on the caudal side of the joint and are connected to the femoral condyles.

The proximal intertibia joint connects the head of the fibula to the lateral condyle of the tibia via the cranial and caudal ligaments of the fibular head.

The cruciate ligaments are located in the center of the joint and consist of intersecting bundles of collagen fibers.

The anterior cruciate ligament originates from the posterior portion of the lateral condyle of the femur and runs anteriorly in a ventromedial direction to the tibia and inserts in front of the intercondylar eminence of the tibia. The posterior cruciate ligament begins in the caudal ligamentous fossa of the intercondylar eminence and ends in the intercondylar fossa of the femur. The anterior cruciate ligament itself consists of longitudinally oriented collagen fibers, the purpose of which is to prevent displacement of the tibia in the cranial direction during flexion and extension of the knee joint, rotation of the tibia, and prevention of hyperextension of the knee joint.

Accordingly, when it ruptures, the dog experiences instability in the knee joint and with each step the lower leg moves in the cranial direction and normal movement of the limb becomes impossible. Instability in the knee joint very often leads to damage to the medial meniscus, which further aggravates the course of the disease and prognosis.

Etiology of ACL rupture in dogs

There are several causes of anterior cruciate ligament rupture, but the most common is degenerative changes in the ligament itself. Due to various predisposing factors, the cruciate ligament becomes thinner, its nutrition is disrupted, the ligament becomes inelastic and any unsuccessful movement of the dog leads to its rupture.

With degenerative changes in the anterior cruciate ligament, its rupture, as a rule, occurs gradually, and clinical signs increase over time. That is, first the dog’s cruciate ligament is torn, and the dog begins to limp, then with a slight jump or playing with other dogs, it completely ruptures with clear clinical manifestations. As stated above, rupture of the anterior cruciate ligament due to degenerative changes in the ligament itself is the most common cause of rupture in dogs aged 5 to 7 years.

In younger dogs, degenerative changes in the anterior cruciate ligament and its rupture can occur as a result of congenital deformities of the knee joint itself or other pathologies of the pelvic limb, for example, hip dysplasia or luxation of the patella in small breeds of dogs. As a result of improper load on the ligament, it undergoes changes and ruptures.

Rupture of the anterior cruciate ligament due to injury to the knee joint practically does not occur in veterinary practice, and if it does occur, it is usually due to severe sprain of the knee joint, for example, during a car injury.

Another cause of anterior cruciate ligament rupture is immune-mediated or infectious inflammatory arthropathy.

Predisposing factors for anterior cruciate ligament rupture may also include excessive slope of the tibial plateau or excessive caudal slope of the superior articular surface of the tibia and stenosis of the intercondylar recess of the femur.

Excessive tilting of the tibial plateau places excessive stress on the cruciate ligament and can cause it to become damaged and rupture.

The theory of insufficient intercondylar recess has its origins in humane medicine. In humans, anterior cruciate ligament rupture can occur as a result of impingement of the medial surface of the lateral femoral condyle with the cranial cruciate ligament. In dogs, this theory has reason to exist, since when studying knee joints, scientists in 1994 noted that all studied joints with torn anterior cruciate ligaments had less pronounced intercondylar grooves compared to healthy joints.

Symptoms of a torn ligament and who is usually injured

Symptoms of a cruciate ligament rupture:

• sharp pain in the knee joint (the dog whines, licks its paw);
• lameness on one pelvic limb (limitation of movements and obvious disturbance of gait);
• joint swelling;
• in a sitting position, takes a forced position (places the sore paw differently);
• the dog may even refuse to eat.

Unfortunately, it is impossible for the owner to visually determine what injury has occurred and what to do in this case. Therefore, it is necessary to contact a veterinarian orthopedic traumatologist as soon as possible in order to correctly diagnose the problem and begin treatment in time before the pet stops walking completely.

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Which dogs are most likely to tear their cruciate ligament?

In this article we will discuss a torn anterior cruciate ligament (ACL) in dogs, as in more than 70% of cases, a torn ACL is the cause of lameness and knee pain. Rupture of the anterior cruciate ligament is the most common orthopedic disease in dogs and inevitably leads to the development of degenerative changes in the knee joint (Corr SA, Brown C., A., 2007).

Who does it happen to most often?

A torn cruciate ligament can occur in dogs of any breed with completely different activity levels and physical fitness. However, it is more common in giant and large breeds, or in small overweight dogs.

The likelihood of getting such an injury increases sharply if the dog is a hunting dog or leads a very active (sports) lifestyle. However, in urban areas there are very few such applicants.

Pets that live a couch potato lifestyle also have a high risk of anterior cruciate ligament injury due to excess body weight. The fact is that the size of the joints and ligaments in a small dog are not initially designed for higher weight. For example, if a Yorkie weighs 6-7 kg, then the small joints cannot withstand such a high load, and this increases the risk of ligament injury. But sometimes an imbalance is also observed in large dogs that have large muscle mass, but at the same time very thin limbs.

There is also a breed predisposition. For example, the risk of cruciate ligament injury increases in Central Asian Shepherd Dogs, Labradors, Staffordshire Terriers, English Bulldogs, Newfoundlands, Dobermans, etc.

The ligament can also tear if the dog already has a tendency to hyperextend the knee joint.

Sexual predisposition is not noticed - both males and females are injured.

According to foreign data, rupture of the anterior cruciate ligament is most often observed at the age of 5 years, and according to statistics from the Russian Federation - in the period from 4 to 6 years. The reason is that the usual prerequisites for ACL rupture are initial degenerative changes in the joint. Consequently, these changes still have time to develop over some time.

To better understand the causes and mechanism of injury, we would first like to briefly introduce you to the anatomy of the cruciate ligaments in dogs.

Clinical signs of ACL rupture in dogs

The most common clinical sign of anterior cruciate ligament rupture is pain when moving the knee joint. With a partial rupture, the pain syndrome may not be very pronounced and the dog will limp slightly on the affected leg. With a complete rupture, the pain syndrome is more pronounced, the dog experiences severe lameness of the supporting type, or the dog generally loses the ability to use the affected paw and keeps it in a bent state.

When the anterior cruciate ligament ruptures, swelling of the knee joint and increased local temperature may occur. This may be due to infection in the knee joint or secondary inflammation due to instability after rupture.

The presence of instability in the knee joint, this clinical sign is usually assessed by a veterinarian using tests that are performed on the knee joint. In a complete rupture that has occurred recently, the instability is usually much more pronounced and can be easily assessed by a veterinarian. Also, instability in the knee joint is well diagnosed in small breeds of dogs and can even be noticed by the dog owners themselves. In large breed dogs, instability after approximately 3-4 weeks may be less pronounced due to the presence of chronic inflammation and peri-articular fibrosis, making diagnosis more difficult. With a partial rupture of the anterior cruciate ligament, instability in the knee joint will not be observed, but pain and lameness will be clinically observed. Swelling of the knee joint is rare.

Partial rupture of the anterior cruciate ligament

Complete rupture of the anterior cruciate ligament

A clicking sound may also be heard when the knee joint flexes. This clinical sign is observed when the medial meniscus is damaged, when the torn part of the meniscus can bend between the articular surfaces of the medial femoral condyle and the tibial plateau and create a characteristic sound when the knee joint is flexed. This is not uncommon in large dogs. Damage to the medial meniscus can worsen over time, when the meniscus is rubbed against the articular surfaces and becomes even more unusable. If the medial meniscus is damaged, then over time arthritic changes will be observed in such a joint, since the meniscus performs very important shock-absorbing functions in the knee joint.

Usually, with a complete rupture of the anterior cruciate ligament, at first the clinical signs will be very pronounced, but over time they begin to subside, and the dog may begin to move on the affected limb and, accordingly, this is not very good for the meniscus. Prescribing painkillers accordingly is also not permissible in order to avoid movement in an unstable joint.

As for long-term clinical signs, this is atrophy of the thigh muscles, arthrosis of the knee joint, which is not uncommon for dogs with a rupture of the anterior cruciate ligament.

Atrophy of the thigh muscles develops if the dog does not give proper weight to the affected leg, and it can walk on both legs, but try to transfer its body weight to the healthy hind limb. Atrophy can be easily seen by comparing a healthy paw and a diseased one; a paw with a ligament rupture will appear thinner, the muscles will feel flabby and lack normal tone.

It is more difficult to determine atrophy when the anterior cruciate ligaments are torn in both legs, simply due to the impossibility of comparison, but an experienced specialist should be able to cope with this.

With arthrosis of the knee joint with rupture of the anterior cruciate ligament, when palpating and flexing the knee joint, crepitus may be felt in the joint itself, the knee joint will be increased in size, especially on the medial side, and contracture may be observed.

Diagnosis of anterior cruciate ligament rupture in dogs

A torn anterior cruciate can be diagnosed using special tests performed by a veterinarian at an appointment and special diagnostic studies.

When examining a sore joint, two special tests must be performed to diagnose anterior cruciate ligament rupture:

• Henderson compression test (calf compression test). To perform this test, the dog must be placed on its side with the affected paw extended. With one hand, the doctor fixes the knee joint and also places the index finger on the tibial tuberosity, and with the other hand, flexes the hock joint. With a complete rupture of the anterior cruciate ligament, the tibia will move forward during flexion and, accordingly, this can be felt by the pathological movement of the tibial tuberosity.
• Cranial drawer test (cranial tension). To perform this test, the dog is also placed on its side. The affected limb is located on top. With one hand, the doctor fixes the femur, and with the other hand, fixes the tibia and tries to move it in the cranial direction. Normally, there should be no cranial displacement of the tibia relative to the femoral condyles; if it is present, it means there is a rupture of the ACL.

Sometimes it makes sense to carry out both tests under anesthesia, especially if you suspect that the rupture occurred a long time ago and there is already arthrosis in the knee joint. When diagnosing old ACL tears, tests may not be very informative and displacements during tests may be insignificant due to the presence of peri-articular fibrosis, so minimal displacement can only be noticed in a relaxed joint, so such patients are given a sedative.

If the anterior cruciate ligament is torn, these tests will be negative.

X-ray examination for rupture of the anterior cruciate ligament is not a specific and sufficiently informative study, since the diagnosis is mostly made on the basis of a clinical examination of the joint. X-ray diagnostics can be useful for detecting consequences after rupture of the anterior cruciate ligament, in particular the presence of deforming osteoarthritis. During X-ray diagnostics, the following changes will be noticeable: osteophytes will be present in the area of ​​the patella, on the medial side of the knee joint and in the area of ​​the sesamoid bones. The articular surfaces of the knee joint may also have defects; there may be loose fragments of cartilage and bone structures in the joint cavity.

Computed tomography of the knee joint in case of rupture of the anterior cruciate ligament, as well as radiographic examination, is not sufficiently informative for this pathology. With CT, we can clearly evaluate the bone structures of the joint, their changes or the presence of osteophytes. Soft tissue structures such as the lateral and medial menisci and the cruciate ligament are difficult to assess.

Special attention should be paid to such diagnostic research as arthroscopy of the knee joint.

Arthroscopic examination of the knee joint is extremely important in cases of partial rupture of the anterior cruciate ligament. This method makes a diagnosis in the absence of a positive response to the drawer test or calf compression test. Also, arthroscopic minimally invasive surgery of the knee joint is actively used in our clinic. Using it, we can assess the condition of the menisci, carry out manipulations for partial or total removal of the meniscus, remove fragments of the anterior cruciate ligament - minimally invasive!; that is, with the least surgical trauma, and then apply a technique to stabilize the knee joint.

MRI of the knee joint is a diagnostic area that is currently beginning to be considered as a highly informative study of the knee joint in veterinary medicine. An MRI of the knee can show damage to the meniscus, partial or complete tear of the anterior cruciate ligament, and other joint structures. Unfortunately, due to the high cost of equipment, not every clinic can afford to conduct such a study.

Treatment of cruciate ligament rupture in dogs

The choice of treatment method for a ruptured anterior cruciate ligament depends on various factors, such as the dog’s body weight, the angle of the tibial plateau, how long the disease has been, etc., but in any case everything should be aimed at eliminating pain and improving the dog’s quality of life.

There are two methods of treating a torn ACL:

Therapeutic treatment

Therapeutic treatment for anterior cruciate ligament rupture means:

• Limiting the dog's mobility, such as walking with the animal on a leash or keeping the dog in a small enclosure where active movements are not possible. Accordingly, you need to avoid active games with the dog, various jumps, etc. Restriction of mobility should be carried out for one month, in some cases for a longer period.

• Non-steroidal anti-inflammatory drugs. Drugs in this group are prescribed to eliminate pain and inflammation in the knee joint.

These NSAIDs are very widely represented on the veterinary market, but in our practice we most often use only a small range of drugs from this group.

For small breeds of dogs we use the following medications:

• Loxicom (0.5 mg meloxicam in 1 ml) suspension. For dogs weighing up to 5 kg. The drug is prescribed on the first day of administration, 0.4 ml per 1 kg of body weight, then 0.2 ml per 1 kg of body weight of the animal, strictly after feeding. Course up to 10 days. The drug can be used for animals from 6 weeks of age.
• Previcox 57mg (firocoxib) tablets. For dogs weighing over 3 kg. The drug is prescribed in a dosage of 5 mg per 1 kg of body weight, strictly after feeding the dog. The drug can be used from 10 weeks of age and if the dog weighs more than 3 kg.

For dogs of larger breeds, we most often use drugs such as:

• Previcox 227 mg (firocoxib) tablets. The drug is prescribed in a dosage of 5 mg per 1 kg of body weight, strictly after feeding the dog. Also, the dosage calculation table is given above.
• Rimadyl 20,50,100 mg (carprofen) tablets. The drug is prescribed in a dosage of 4 mg per 1 kg of body weight, strictly after meals. The drug is not prescribed to dogs under 12 weeks of age.

It should be remembered that all nonsteroidal anti-inflammatory drugs can cause irritation of the mucous membrane of the stomach and intestines, leading to the development of erosions and ulcers, but when used correctly, this is extremely rare. NSAIDs are also used with caution in dogs with liver or kidney disease, as they may have hepatotoxicity and nephrotoxicity. Therefore, before using the drug, it is recommended to conduct a biochemical blood test to avoid subsequent problems.

• Use of special knee pads for dogs.

Separately, the use of knee pads for dogs is not used as an independent therapeutic treatment. In complex therapy, for example, with insufficient limitation of mobility, this method can be useful as additional support for the knee joint when the dog moves. Most often, due to the anatomical structure of the dog’s limb, the knee pad slips off the paw or the dog itself tries to remove it, which makes this method ineffective.

In itself, the therapeutic approach to rupture of the anterior cruciate ligament is not the gold standard in the treatment of this pathology and often leads to the development of deforming osteoarthritis of the knee joint, which over time makes movement in the affected paw impossible. Therefore, in our clinic this type of treatment is offered to patients who have contraindications to general anesthesia or when surgical treatment is not possible at the request of the owners.

Surgical treatment of cruciate ligament rupture in dogs

Surgical treatment for anterior cruciate ligament rupture is the most reliable method that gives the best result. Let's consider several methods of surgical treatment for rupture of the anterior cruciate ligament:

• Intracapsular methods.

The goal of the intracapsular technique is to restore stability to the knee joint by replacing the ligament with a graft. In the supra-apical method of surgery, the graft consists of a straight patellar ligament, a patella wedge, a patellar tendon and fascia lata. It is placed along the course of the original cruciate ligament in the knee joint, in its normal anatomical position. Over time, the graft should take root in the knee joint, its blood circulation should be restored and over time it will resemble a healthy cruciate ligament.

All intracapsular stabilization methods have their positive sides: complete replacement of the anterior cruciate ligament. In biomechanical terms, this method has its noticeable advantages.

On the other hand, there are also some negative aspects: after replacing a ligament, it immediately puts a significant load on it and it may not take root and may rupture. Also, if a dog has a deformity of the knee joint, as a result of which degenerative changes in the cruciate ligament have occurred and it has torn, then there is no point in replacing the ligament. There are also operational technical difficulties in replacing it.

• Extracapsular methods (FTS or lateral suture, muscle transposition).

Extracapsular techniques rely on stabilizing the knee joint with sutures or using soft tissue to support the knee joint.

- Fabello-tibial suture or lateral suture.

Stabilizes the knee joint due to the formation of fibrous tissue around the implant (suture). The lateral suture is placed on the lateral side of the knee joint through a double hole in the area of ​​the tibial tuberosity. The other end of the thread is passed through the lateral fabella with a needle. Next, both ends of the thread are passed through the clip, the thread is pulled tight and the clip is clamped.

This method is good for dogs no more than 12-15 kg. The ability to support the affected limb after surgery occurs on days 7-14, and by the 12th week the lameness disappears.

— Transposition of muscles.

Stabilization of the knee joint is achieved by transferring the distal end of the biceps femoris muscle and the distal end of the sartorius muscle to the crest of the tibia. As a result, the knee joint remains stable when moving, and no cranial displacement of the tibia is observed.

This method is suitable for dogs of any weight and is quite inexpensive. The ability to support the affected limb is restored after 4-6 weeks. Complete lameness can take up to 4-5 months.

This method has its long-term disadvantages, such as secondary damage to the medial meniscus and the development of osteoarthritis.

Also, this method requires limiting the dog’s mobility for up to 4 weeks, which is not always possible, otherwise, separation of the displaced muscles may occur.

• Around joint methods (Osteotomies: TPLO, TTA, TTO). These methods are based on changing the anatomical structures of the joint for restoration.

— TPLO leveling osteotomy of the tibial plateau (tibialplateaulevelingosteotomy) is a surgical method based on reducing the angle of the tibia, where the forces of movement during extension provide dynamic stabilization of the joint.

This method of treatment for rupture of the anterior cruciate ligament is one of the most reliable surgical techniques. Suitable for dogs of all weight categories with a tibial plateau angle greater than 15 degrees. The goal of TPLO is to dynamically stabilize the knee joint. The cranial displacement of the tibia in case of rupture of the anterior cruciate ligament is caused by the angle of inclination of the tibial plateau by the compression traction that occurs when the body weight is transferred to the injured limb, directed parallel to the longitudinal axis of the tibia. If the plateau angle is 5-6.5°, then there will be no displacement of the tibia in the cranial direction and the joint will be stable. Osteotomy is performed using an oscillating saw and a blade of a specially selected radius. Then, after changing the angle, the plateau is fixed relative to the tibia with a special plate for the TPLO (“clover leaf”) technique.

After this technique, dogs with a rupture of the anterior cruciate ligament have a fairly early ability to support the affected paw. After 5-7 days, dogs actively use their paws. Postoperative care does not require strict restriction of mobility; the use of antibiotics, non-steroidal anti-inflammatory drugs and suture treatment is recommended. If the menisci are damaged with this technique, arthrosis of the knee joint develops much more slowly. Like any other technique, this method has its complications, such as infection of the implant (2%), avulsion of the tibial tuberosity (4.3%), secondary damage to the meniscus (3%).

— TTA advancement of the tibial tuberosity (Tibial tuberosity advancement) – the surgical method is based on the advancement of the tibial tuberosity, where, during extension, additional dynamic traction is created, directing the tibial plateau to its natural position.

The essence of this technique is that if an angle of 90 degrees is achieved between the direct patellar ligament and the tibial plateau, then the cranial displacement of the tibia will not be observed, and accordingly the knee joint will be stable.

The technique is suitable for dogs of different weight categories, as well as with a tibial plateau angle of less than 15 degrees. In the postoperative period, the use of antibiotics, non-steroidal anti-inflammatory drugs and suture treatment is recommended. The advantage of the method is also the early ability to support, the disadvantage is the development of postoperative seromas (33%) and separation of the tibial tuberosity (15%). TTA is not used as often in our clinic due to aspects of the high cost of the implants, as well as the higher rate of postoperative complications compared to TPLO.

— TTO (Triple Tibial Osteotomy).

The essence of this method also consists in changing the anatomy of the tibial plateau, namely, changing the angle of the plateau and extending the tuberosity using osteotomy. This technique is performed on dogs whose plateau angle is less than 15 degrees. There are also a number of disadvantages, such as the traumatic nature of the operation, separation of the tibial tuberosity and severe postoperative limitation of mobility.

When is surgery required and why are there so many techniques?

Let us repeat, today there are more than 20 surgical techniques for rupture of the cruciate ligament in a dog. However, for convenience, all surgical techniques can be divided into two large groups of techniques:

1. Reconstruction of the anterior cruciate ligament using different methods
2. Modification of biomechanics of the dog knee joint

Reconstruction or replacement of the anterior cruciate ligament

Let us remind you that the contraction of the muscles (quadriceps and popliteal gastrocnemius) leads to the fact that with each step the dog takes, the lower leg wants to move forward relative to the thigh, but the anterior cruciate ligament prevents the lower leg from doing this. That is, normally the knee joint works smoothly and nothing goes anywhere.

Biomechanics of the knee joint

When the ligament ruptures, the lower leg begins to move forward with any movement of the limb (cranial displacement), which is not normal. Since it is impossible to sew up or repair a torn ligament, traditional treatment is used by creating an artificial ligament.

Reconstruction or prosthetics of the anterior cruciate ligament is the replacement of a torn ligament by installing (implantation) a specific implant, which will again prevent the lower leg from moving forward

Imitation of the function of the anterior cruciate ligament (ACL) can be:

1. Intra-articular reconstruction of the ACL is the installation of implants inside the joint (autograft, polymer prostheses).
2. Extra-articular reconstruction of the ACL is an extra-articular placement of implants (autograft in the form of durable dyneema, plastic surgery of the joint capsule, muscle transposition, or the application of a special fabelotibial suture).

With any of these methods, the artificially created ligament for some time performs the function of the anterior cruciate ligament, i.e., it prevents the lower leg from moving forward relative to the dog’s thigh.

Pros of reconstruction:

• restoration of the function of the knee joint - the dog can lead a normal life by eliminating the displacement of the lower leg and immobilizing the joint (stops “dangling”);
• over time, connective tissue grows, which subsequently holds the knee joint (i.e., periarticular fibrosis develops, which leads to relative stabilization of the knee joint).

Disadvantages of some traditional treatment by simulating ACL function:

• pain after surgery;
• During surgery, it is easy to damage other structures of the limb;
• deformity of the knee joint;
• osteoarthritis progresses due to residual instability in the knee joint.

Cruciate ligament replacement is not advisable if there is a biomechanical imbalance in the knee joint

Real outcomes:

1. In most cases, sooner or later, failure of the prosthesis develops - the implant slips off and can cut through adjacent ligaments.
2. Preservation of instability - no matter how firmly the implant is initially installed, after a month the tension will weaken and micro-instability will appear, since the biomechanical imbalance in the joint was and remains.
3. Development and progression of osteoarthritis.

Failure of the prosthesis when simulating the anterior cruciate ligament

Traditional treatment (ligament replacement) has many disadvantages because we become hostage to the implant. If something happens to it, instability in the joint immediately resumes, and all the problems repeat again.

HELP DEAL WITH THE PROBLEM

Modification of biomechanics of the dog knee joint

If, after diagnosis, it becomes known that the cause of the anterior cruciate ligament rupture is a biomechanical imbalance, then the main goal should be to correct this balance. If you close your eyes to this important fact, the installed implant (imitation of a ligament) will rupture after the operation in the very near future. However, if the resulting biomechanical imbalance is eliminated, then the ligament will not be needed at all.

In the previous article we talked about what a plateau is and why measure corners. Let us recall that the essence of biomechanics is a change in the TPA angle (the ratio of the tibia to the knee joint), which normally should be no more than 5-8 degrees.

If a dog's lower leg moves forward relative to the hip during movement due to a rupture of the anterior cruciate ligament due to an incorrect angle of inclination of the tibial plateau, this same angle of inclination needs to be changed, thereby eliminating the problem

Principles on which new techniques for biomechanical knee stabilization are based

Let's consider the problem of ligament rupture using the example of two carts. You can mount the cart standing on an inclined plane in any way you like. But the forces acting on it will not go away - the cart will always be ready to roll back as soon as the cable holding it breaks. However, if you change the slope of the surface, the cart will stand level and will not roll anywhere - there is no need for a rope. It is on these principles that new techniques for biomechanical stabilization of the knee joint are based.

New techniques do not aim to replace a torn anterior cruciate ligament and continue to resist forces in the knee joint. The first goal of biomechanical stabilization is to make the ligament completely unnecessary by changing the angles of inclination - this is the only way to neutralize the forces in the knee. And since there are no more active forces, then the lower leg will stop moving forward with each step.

For example, in a wolf and some dogs the angle of inclination of the tibial plateau is 12°-13°. This means that our “cart initially stands still and does not try to go back.” Therefore, if the anterior cruciate ligament ruptures, the animal will only limp for a month, and everything will pass. In this case, surgery is not necessary, since stability in the joint is achieved as a result of the natural growth of connective tissue, which subsequently holds the knee joint (periarticular fibrosis). However, in almost all dog breeds the angle of inclination is much higher, so it is simply impossible to do without surgery - “the cart just wants to leave.”

The second goal of biomechanical stabilization is to stabilize the joint as much as possible and, if possible, maintain the supporting surface over a large area so that the meniscus is preserved to prevent the prerequisites for the development of osteoarthritis.

Earlier in the article, we described in detail what menisci are, their role, why they get injured and why they are so important in general. Let us briefly recall that the dog's thigh rests on the surface of the lower leg through the medial and lateral menisci. Since these two bones have different surfaces, the menisci with intra-articular fluid act as a layer, thanks to which there is a stable connection in the knee with uniform load distribution.

If there were no menisci, then the thigh would rest on the shin in just two small points, which would significantly increase the load (friction) in these places. Because of this, the temperature would begin to rise, which would inevitably lead to overheating in the joint, and subsequently to cartilage necrosis and the development of osteoarthritis.

Let's consider several well-known methods for modifying the biomechanics of the dog's knee joint

All techniques eliminate the tendency of the lower leg to move forward, however:

• TTA and TTA2 – places the force towards the plateau;
• TPLO, TTO and TWO – positions the plateau towards the force.

TTA technique for cruciate ligament rupture in dogs

The TTA (Tibial Tuberosity Advancement) technique is a technique in which the doctor moves the patellar ligament forward during surgery, but the tibial plateau remains in place. Thanks to this method, the tibial plateau meets the femur not at an angle, but perpendicularly. Consequently, the direction of the force vector also becomes perpendicular, so the shin no longer shifts.

TTA technique for anterior cruciate ligament rupture in dogs

Advantages of the TTA technique:

1. It is believed that this method, compared to others, increases the load on the knee joint the least.
2. Consequently, secondary degenerative disorders in the joint are minimized.
3. During the operation, it is possible to simultaneously solve the second problem – patellar dislocation.

Disadvantages of the TTA technique:

1. The technique cannot be used if the initial angle of inclination is too large (15°-25° or more).
2. Deformation of the limb after surgery.
3. Slowing of bone fusion due to cytokines and metalloproteinase enzymes contained in the intra-articular fluid that enters the cut site during intra-articular surgery.
4. High risks of complications.
5. Despite the fact that the method is relatively simple, the operation requires special instruments and implants.
6. Relatively high cost of surgery.

Perhaps, in veterinary clinics, someone else uses the TTA technique, but the Alisavet network of veterinary clinics uses a new version of this technique - TTA2

TTA2 technique for cruciate ligament rupture in dogs

The TTA2 (Tibial Tuberosity Advancement 2) technique is an updated version of the TTA technique. The general principle of surgical intervention and preoperative calculations are the same as for the first TTA, however, the methods by which the advancement of the tibial tuberosity and the redistribution of forces acting on the joint are achieved have obvious differences.

According to the TTA2 technique, the cut inside the bone is shorter, and the implant (spacer) of the updated version has a different shape that does not require fastening with screws.

Advantages of the TTA2 technique over the first TTA technique:

1. Since there is now no need to use a complex metal structure and there is no need to completely saw off the tibial tuberosity, the operation time is significantly reduced. Also, the effect of anesthesia on the animal’s body is also minimized.
2. The first TTA uses a titanium alloy spacer, but the TTA2 technique uses an implant made of titanium, aluminum and niobium coated with calcium phosphate, which now provides better biocompatibility and reduces the risk of postoperative infection.
3. The TTA2 technique also differs from the first in that a special suture is now placed at the bottom of the cut, which prevents the tuberosity from coming off the bone.
4. With TTA2, it is no longer necessary to attach a plate to the tibial tuberosity and secure the spacer with screws. Consequently, there is now no need to separate the bone from the soft tissues, so tissue trauma with the updated technique is minimal.

Below is a video of a dog 10 days after surgery using the TTA2 technique

Below is a video of a dog 1.5 months after surgery using the TTA2 technique

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TPLO technique for cruciate ligament rupture in dogs

The TPLO technique (Tibial Plateau Leveling Osteotomy) is a standard, certified technique in which the physician makes a single semicircular cut at the edge (proximal metaphysis) of the tibia. And this sawn-off fragment is rotated so that the angle of inclination becomes perpendicular to the load vector.

After the operation, you will notice on the x-ray the appearance of the so-called “balcony effect” - this is precisely part of the displaced excised bone fragment. Don't be alarmed - this is the norm with this technique.

Advantages of the TPLO technique:

1. This technique makes it possible to measure angles several times during the operation, take control photographs, conduct a compression test, and rotate the sawn fragment precisely to the desired angle without errors.
2. Another good thing about this method is that, thanks to the large contact area, high stability is achieved at the cutting site.
3. According to scientific data, it has been established that after surgery using the TPLO technique, the dog’s osteoarthritis practically does not progress and the menisci in the knee joint are not damaged, which is a positive assessment of this technique.

Disadvantages of the TPLO technique:

1. Slowing of bone fusion due to cytokines and metalloproteinase enzymes contained in the intra-articular fluid that enters the cut site during intra-articular surgery.
2. Due to the fact that all bone components are tightly fixed with a metal plate and special screws, that is, there are restrictions on the weight (preferably from 30 kg) and age (preferably adults) of the animals: for small breed dogs, such an operation is very problematic due to the small area of ​​the bones, and in young dogs we will use a screw to block the growth zone.
3. If the initial angle in the dog’s knee joint is too large, such a technique becomes impossible (it will result in a “balcony” that is too large, which is not desirable).
4. Dog owners are not always able to pay the high cost of implants (plate and screws).

TTO technique for cruciate ligament rupture in dogs

TTO (triple tibial osteotomy) technique – this technique combines the advantages of the TPLO and TTA techniques. During the operation, the doctor slightly moves the patellar ligament and, using three straight cuts, changes the angle of the tibial plateau.

TTO technique for anterior cruciate ligament rupture in dogs

Advantages of TTO technology:

1. A “balcony” is not formed, as with TPLO, therefore this technique can be used on dogs of slightly less weight, but again not on small breeds, since small bone is again not suitable for triple cutting.
2. More accessible instruments and implants, which makes the operation cheaper.
3. The technique is well suited if the dog also has a luxated patella - several problems can be corrected at the same time.

Disadvantages of TTO technology:

1. There is a risk of limb bending if the wedge is cut incorrectly into the bone.
2. In almost 40% of cases, a fracture is observed in the area of ​​the large cut (bone roughness fracture). Therefore, do not be surprised if your veterinarian prevents this complication in advance by strengthening the bone.
3. Since the cut is again intra-articular, then, as with TPLO, there will be a slowdown in bone healing due to cytokines and metalloproteinase enzymes contained in the intra-articular fluid that enters the cut site.

TWO (CWO, TCWO) technique for cruciate ligament rupture in dogs

The TWO (double tibial osteotomy), CWO, TCWO (tibial closed wedge osteotomy or tibial osteotomy with a closed wedge) techniques are very similar, but have their own characteristics. In essence, these are relatively simple techniques in which the doctor makes two straight cuts in the shape of a wedge.

TWO technique for anterior cruciate ligament rupture in dogs

Advantages of TWO, CWO and TCWO techniques:

1. A relatively simple technique using simple implants, which makes the operation quite affordable.
2. Freedom of correction in any plane, which makes it possible to correct previously curved limbs (in this case, the doctor can cut out two wedges).
3. There will be no problems with the healing of bone tissue, since the joint is not affected, therefore, intra-articular fluid does not get into the cuts.
4. The implant (plate and screws) is easily installed, so this technique can be performed on small (from 0.8 kg) and very active dogs, as well as disproportionate animals and overweight pets (up to 80 kg).
5. According to scientific data, the method has a good result based on clinical status, radiological assessment and owner questionnaire.

Disadvantages of TWO, CWO and TCWO techniques:

1. The ligament of the kneecap is stretched more strongly, which creates a greater load on the cranial part of the cut and increases the vector force on the joint.
2. Therefore, if you use fixation only with a plate, then there is a high risk of tearing off part of the bone (cranial edge), after which the place of artificial contact diverges. However, doctors usually prevent this consequence in advance by additionally applying a tightening loop with a metal wire (wire cerclage).
3. The kneecap is displaced.
4. There is no way to accurately calculate the angle of future inclination in advance, since the mechanical axis of the lower leg changes slightly after surgery.

CBLO technique for cruciate ligament rupture in dogs

CBLO is a relatively new technique in which the doctor makes a single semicircular cut at the edge of the tibia. After which the sawn fragment is rotated so that the angle of inclination becomes perpendicular to the load vector. However, unlike the TPLO technique, the semicircle turns out in the other direction, which eliminates the appearance of the “balcony effect”.

Comparison of CBLO and TPLO techniques

Advantages of the CBLO technique:

1. A relatively simple technique to prepare and perform.
2. The anatomical integrity of the bone is preserved as much as possible.
3. The technique maintains normal pressure distribution and natural biomechanics of the knee joint.
4. Unlike standard TPLO, this technique does not create posterior traction (caudal traction).
5. The technique can be used in young animals and even with a strong slope of the plateau.

Disadvantages of the CBLO technique:

1. This technique cannot be combined with the correction of medial dislocation of the kneecap, nor can it correct the consequences of a rupture of the anterior cruciate ligament.
2. It is believed that this method causes excessive tension on the patellar ligament.

What is the best technique for torn anterior cruciate ligament in dogs?

Now there are many scientific articles where different techniques are compared with each other. However, no single scientific evidence of the best surgical technique has been identified, which proves its superiority over other techniques.

For anterior cruciate ligament rupture in dogs, veterinarians often combine several techniques during a single surgical procedure.

Combination of techniques during surgery

Whatever method or combination of methods the doctor chooses, the results, risks and consequences are similar. However, we must not forget about logic, because each technique has its own limitations under certain conditions.

Although there is no scientific evidence, there are general medical observations of the consequences after carrying out certain techniques:

1. After reconstructive techniques (artificial ligament) in dogs, in most cases osteoarthritis progresses due to residual instability in the knee joint. It is impossible to avoid this, since the only important link is the implant in the form of an imitation of the anterior cruciate ligament.
2. After modification of the biomechanics of the knee joint, osteoarthritis in operated dogs, as a rule, does not develop, which is an excellent indicator.

The use of techniques for modifying the biomechanics of the knee joint (biomechanical stabilization of the joint) has a clear advantage over reconstruction (replacement methods) of the canine anterior cruciate ligament. And if in simple words...

It is better to use a technique that eliminates the need for an anterior cruciate ligament in the dog than to try to artificially replace it.

HELP DEAL WITH THE PROBLEM

What may happen immediately after surgery?

The next day or 2-3 days after surgery, swelling of the lower leg may appear. In such situations, the following are helpful:

• applying cold;
• use of painkillers;
• low activity;
• massage;
• other help depending on the situation (the veterinarian decides).

For very severe swelling, special hormonal agents are used. Usually by the 5th day the swelling disappears. In small breed dogs, as a rule, swelling does not occur at all.

Prognosis for ACL rupture in dogs

The prognosis for recovery directly depends on the time of treatment after rupture of the anterior cruciate ligament.

A secondary problem after anterior cruciate ligament rupture is damage to the medial meniscus. If the dog has been walking with a tear for a long time, the meniscus injury may worsen and during surgery, the posterior horn of the medial meniscus is most often removed partially or completely. Removal of the meniscus, chronic inflammation of the knee joint, etc., leads to the development of arthrosis of the knee joint, which in the future will lead to the inability to fully use the paw.

Also, with prolonged pain in the dog’s knee joint, atrophy of the hip muscles occurs, which aggravates the rehabilitation period after surgery.

In conclusion of this article, I would like to note the main recommendation for animal owners - timely seeking help from a veterinarian.

REMINDER FOR THE PATIENT IF AN ACL RUPTURE IS SUSPECTED

• It is strictly forbidden to put weight on the injured leg and try to “diverge”. it's so easy to make the problem worse.
• Even if the pain is not severe, you need to immobilize the joint: apply a bandage or plaster, and do not step on the sore leg when walking.
• Apply cold.
• Seek advice from a traumatologist, even if the injury seems minor.

Old knee injuries left without treatment will definitely remind you of themselves: the knee will hurt, react to the weather, osteoarthritis may develop - in advanced cases this is an indication for prosthetics. If ignored, surgery will eventually be required to repair the joint. Surgery is not the best treatment: the recovery process may take six months, but the knee after ligament replacement will never be as mobile and resilient as a healthy one. Therefore, if you have any damage, pain, or instability after an injury, contact a traumatologist. The Doctor Ost MC presents modern methods for restoring the ACL after a rupture.

Clinical case No. 1

The owners of an Alabai dog named Yuzbash contacted the Pride Center with complaints about lameness of the pelvic limb in their pet.

As a result of an orthopedic examination and x-ray examination, a diagnosis was made of a torn anterior cruciate ligament. This problem was solved using surgical treatment using the TPLO (Tibial plateau leveling osteotomy) technique. This is a modern technique that allows you to achieve quick and effective results. This technique involves changing the angle of the tibial plateau, at which the anterior cruciate ligament loses its functional significance.

5 days have passed since the operation, and Yuzbash can already use his paw. Rehabilitation after such an operation does not require a lot of time and expense for the owners.

Veterinary surgeon, specialist in traumatology, orthopedics and neurology Maslova E.S. Veterinary anesthesiologist K.V. Litvinovskaya

What are the stages of the TPLO operation?

Preoperative planning:

1. Measuring the tibial plateau angle;
2. Calculation of “rotational” displacement for the osteotomized segment;
3. Selection of the appropriate size of biradial saw blade;
4. Selection of the required implant.

Intraoperative steps when performing TPLO:

1. Iedial arthrotomy;
2. Revision of the joint with excision of the damaged anterior cruciate ligament + damaged meniscus;
3. Joint suturing;
4. Radial osteotomy of the proximal segment of the tibia;
5. Fixation of the osteotomized segment with a plate;
6. Layer-by-layer suturing of soft tissues.

Postoperative period:

1. Anti-inflammatory therapy;
2. Antibacterial drugs;
3. Body weight control;
4. Dosed exercise (regular moderate physical activity);
5. Hydrotherapy (swimming or water treadmill).

Clinical case No. 2

A poodle dog named Dorphy was admitted to the veterinary because she began limping on her left pelvic limb. Over time, the lameness only worsened.

Veterinary orthopedic surgeon E.S. Maslova A series of examinations (clinical examination of the animal and x-ray examination) and tests (drawer syndrome) were carried out, which made it possible to diagnose a rupture of the anterior cruciate ligament. It was decided to surgically treat the problem using the fabellotibial suture (lateral suture). This technique is performed to stabilize the knee joint when the anterior cruciate ligament is torn in small breed dogs. The technique is considered non-traumatic and dogs recover very quickly after surgery. Dorfi, having passed all preoperative examinations, was allowed to undergo surgery. The dog tolerated the anesthesia, the operation itself and the recovery period well.

Veterinary surgeon, specialist in traumatology, orthopedics and neurology Maslova E.S. Veterinary anesthesiologist K.V. Litvinovskaya

Let's sum it up

A torn cruciate ligament in dogs usually always ends up requiring complex surgery. Each animal is unique and has its own characteristics, which must be taken into account when planning the operation. Sometimes during one surgical intervention it is necessary to use two or three techniques at once, because in addition to a rupture of the cruciate ligament, the dog may also have several other pathologies (meniscus injury, dislocation of the patella, etc.). Therefore, any technique should always be carried out by an experienced veterinarian who has special equipment and suitable quality implants.

Clinical case No. 3

A dog named Kuzya (11 years old) was admitted to the State Educational Center “Pride” to the veterinarian orthopedic surgeon E.S. Maslova. with the fact that the day before at the dacha he stopped stepping on his right pelvic limb. At the appointment, using special tests and radiographic examination, medial dislocations of the patellas on both sides and a rupture of the anterior cruciate ligament on the right were diagnosed.

The causes of anterior cruciate ligament (ACL) rupture vary. In older dogs, ACL rupture occurs for two reasons: degenerative changes in the ligament and inflammatory processes in the joint. This pathology is extremely rarely traumatic in nature, and is always treated surgically.

Since Kuzi has a small body weight, they decided to fix his knee joint using a lateral or fabellotibial suture. This technique involves applying a suture made from a special polymer thread (there are special kits for lateral sutures), which prevent instability of the knee joint. The method is also relatively inexpensive and produces good results, but only for small breeds of dogs. After a preoperative examination by doctor Maslova E.S. Kuza underwent this operation successfully.

Veterinary surgeon, specialist in traumatology, orthopedics and neurology Maslova E.S. Veterinary anesthesiologist Smirnova O.V.

How to diagnose this disease?

The diagnosis is made by a doctor during examination - based on the clinical picture and x-rays. Other pathologies with similar symptoms are excluded - medial or lateral dislocation of the patella, hip dysplasia. All these pathologies can overlap each other. For example, advanced medial luxation of the patella in small breeds can lead to damage to the ACL with age, but in any case it is necessary to differentiate them in order to properly treat them.

Physical examinations include:

1. Henderson compression test;
2. The anterior drawer test (Ortolani test) is a visually observed displacement of the tibia cephalad relative to the femur.

Instrumental methods include:

1. X-ray examination;
2. Ultrasound of the knee joint;
3. Arthroscopy;
4. Magnetic resonance imaging (MRI).

ACL rupture in an Asian Shepherd (chronic process), lateral view

Direct projection of the knee joint in an Alabai with a chronic ACL rupture

Lateral radiograph of a chronic ACL rupture in an Alabai

Clinical case No. 4

A Chihuahua named Lelya (9 years old) was admitted to the Pride State Medical Center to see a veterinarian orthopedic surgeon E.S. Maslova. with lameness on the right pelvic limb. Using special tests and radiographic examination, medial patellar dislocation and right anterior cruciate ligament rupture were diagnosed. This pathology is very common in small breeds of dogs and can only be treated surgically.

Since Lelya is a miniature girl, they decided to fix her knee joint using a lateral (fabellotibial) suture. This technique involves applying a suture made of a special polymer thread, which prevents instability of the knee joint. The method is also relatively inexpensive, non-traumatic and gives good results, but only in small breeds of dogs. After a preoperative examination (blood tests and ultrasound of the heart) by orthopedic surgeon Lele, this operation was successfully performed. And after recovering from anesthesia in the hospital, she went home.

Veterinary surgeon, specialist in traumatology, orthopedics and neurology Maslova E.S. Veterinary anesthesiologist K.V. Litvinovskaya

Postoperative management

Each patient receives a standardized rehabilitation plan, which outlines all necessary rehabilitation measures by period. After the operation, it is necessary to wear a special orthopedic brace with hinges at the level of the knee joint, allowing you to adjust the amplitude of flexion/extension. This brace allows full knee extension but limits flexion to 60 degrees for the first four weeks after surgery and 90 degrees for the next two weeks. After this, full range of motion is allowed. The inpatient stage of treatment takes from 3 to 5 days. Outpatient rehabilitation treatment must be agreed upon by telephone.

Clinical case No. 5

Labrador Uta was admitted to an orthopedic veterinarian E.S. Maslova. with the problem of pain in the left pelvic limb. After examination and a series of orthopedic tests, accompanied by x-ray diagnostics, the dog was diagnosed with crepitus in the knee joint and “drawer” syndrome. The doctor diagnosed him with a torn anterior cruciate ligament. This is a fairly common pathology among dogs. To solve the problem, surgical treatment using the TPLO technique is used. The most modern method that allows an animal to quickly begin to use its paw without the presence of a cruciate ligament. Uta was successfully operated on and went home after waking up under the supervision of his anesthesiologist and doctors in the inpatient department.

Veterinary surgeon specialist in traumatology, orthopedics and neurology Maslova E.S. Veterinary anesthesiologist K.V. Litvinovskaya

Author of the article: Maslova Ekaterina Sergeevna, veterinary surgeon, specialist in orthopedics, neurology and neurosurgery