Cranial cruciate ligament injuries (CCLR) are complete or partial tears of the ligament or avulsions of the origin or insertion.
Cranial drawer is a term used to describe excessive craniocaudal movement of the tibia relative to the femur as a result of cruciate ligament injury.
Cranial tibial thrust is defined as cranial movement of the tibial tuberosity in the cranial cruciate–deficient stifle when the hock is flexed and the gastrocnemius muscle contracts. Translation is defined as movement of a bone parallel to an axis or plane. Pivot shift is cranial movement of the tibia combined with internal rotation of the tibia. Tibial plateau angle (TPA) is the angle between a line perpendicular to the long axis of the tibia and a line parallel to the tibial plateau. Medial buttress is a palpable thickening of the medial aspect of the stifle.
Causes of CCLR
- CCL failure can result from degenerative and traumatic causes. The categories are interrelated, because ligaments weakened by degeneration are more susceptible to trauma.
- The high incidence of CCL failure in dogs suggests that there is an underlying cause of premature degeneration of the cruciate ligament in most cases. Degeneration of the ligament is associated with aging (especially in large-breed dogs), conformational abnormalities (straight rear limbs), and immune-mediated arthropathies. Degeneration of the ligament has also been associated with an increased TPA, although not all studies have identified this correlation.
- An increased TPA has been theorized to place chronic excessive loads on the CCL leading to eventual mechanical failure.
- Acute injury is most commonly associated with the hyper extension and internal rotation of the leg that occurs when a dog’s foot becomes caught in a hole or fence.
- CCL injury with stifle instability is part of a cascade of events that include progressive osteoarthritis and medial meniscus injury. Stifle instability results in synovitis, articular cartilage degeneration, periarticular osteophyte development, and capsular fibrosis. The immobile medial meniscus is subject to injury in the unstable joint. Progressive osteoarthritis occurs after CCL rupture regardless of the treatment method.
The tibial plateau leveling osteotomy (TPLO)
- Changes the mechanics of the stifle to achieve stabilization by active constraint of the joint The stifle joint normally is stabilized by both passive constraints (ligaments, menisci, joint capsule) and active constraints (muscles and tendons). The CCL functions as a passive constraint to cranial tibial translation and internal rotation of the tibia.
- Ground reaction forces and muscle forces generate compressive loads on the articular surface of the tibia during weight bearing.
- As a result of the caudally directed slope of the tibial plateau, when the tibia is loaded, a shear force is generated that induces abnormal tibial translation in CCL-deficient stifle joints.
- The shear component of the compressive force is referred to as the cranial tibial thrust (CTT) and is passively constrained by the CCL.
- The tibial plateau slope can be reduced such that tibial thrust changes from a cranioproximal direction to a neutral or caudal direction.
- At the point where the tibial thrust changes direction to a caudal thrust, there is increased reliance on the caudal cruciate ligament as a passive constraint to abnormal caudal translation of the tibia.
- The intent of TPLO surgery is to attain a tibial plateau slope (approximately 5 to 7 degrees) with which tibial thrust can be effectively controlled by the caudal cruciate ligament and the active constraints of the stifle (e.g., the quadriceps muscle group).
- TPLO is an effective procedure for dogs with a complete or partial tear of the CCL. Many surgeons prefer TPLO for treating larger, active dogs in which long term rehabilitation and postoperative control are difficult.
(Uppermost Text is copied from Small Animal Surgery, Fossum, 4th Edition)
(Before surgical procedures, preoperative x. ray is made to allow for TPA calculation required for rotation measurement, identifying the femoro-tibial translation and OA progression)
- Before TPLO, standard parapatellar lateral stifle arthrotomy is performed to allow for removal of CCL remnants and allow for meniscal procedure (e.g. meniscectomy or meniscal release).
- Lateral to the patella by 2 cm, incision is performed (Skin, s/c, muscles, capsule).
Stifle arthrocentesis can be performed to allow evaluation of the degenerative joint process
- The patella and patellar tendon are reflected to lateral or medial side to allow visualization of the internal stifle structures.
- CCL remnants are removed, meniscus is examined for any tears. The remnants of the ruptured cranial cruciate are removed after removal of the infrapatellar fat pad. The meniscus is examined for any possible tears especially in overweight dogs. In case of meniscal tears, meniscectomy or meniscal release is performed.
- Closure is done by double raw capsular suture followed by muscle closure and s/c and skin
- After Closure of the standard parapatellar lateral arthrotomy, TPLO is performed on the medial side of the proximal tibia.
- Medial incision from the level of the joint till the half of the tibial length followed by dissection till reaching the tibial periosteum.
- Triangle is formed by patellar tendon, joint space and medial collateral ligament.
3. After tibial osteotomy, tibial plateau caudal rotation is performed according to the pre-measured TPA and TPA rotation table.
4. After rotation, TPLO plate is fixed over the two tibial segments. A variety of LCP and DCP plates are used for TPLO.
- The skin is closed routinely by Simple interrupted technique
TPLO postoperative care
1.The total recovery period (until full activity is resumed) is approximately 16 weeks: 8 surgical recovery and 8 weaning into full activity.
2.You will be given rehabilitation guidelines at discharge post-surgery, at the suture removal visit (2 weeks post-op), and again at your 8 week recheck visit for radiographs (x-rays)
First Two weeks
1.Rest and exercise restrictions for 8 weeks.
This allows the incision and bone to heal and the knee function to return. Most dogs recover in about 8 weeks.
2.Leash walk (From the first day of the 2nd week till the last day of the 3rd week).
-Allow your dog to go outside for potty breaks.
-Slings helps bigger dogs get up and walk, if necessary.
3.Avoid jumping, running, climbing steps and roughhousing.
4.Use an Elizabethan collar for the first 2 weeks after surgery to prevent your dog from licking or chewing at the incision site.
5.Keep the incision site clean and dry at all times once your veterinarian removes the bandage or wound dressing.
6.Check the incision twice daily;
-For redness, excessive swelling or drainage.
-The skin staples should be removed 10 – 14 days after surgery.
-Swelling around the ankle is normal and expected the first week postoperatively.
-Apply towel-wrapped ice packs to the area (not directly on the skin).
-Do this 2-3 times per day for up to twenty minutes during the first 48-72 hours following surgery (during the first 3-5 days postoperatively).
-A cool pack that has been in the freezer for 30 plus minutes wrapped in a towel may be applied to the incision site twice daily.
8.Restrict your dog’s activity by using a small area in the home where they can stay and rest, such as a crate or an indoor circular fence.
-with a non-skid floor and NO furniture to jump on or off!
9.Use all medications as prescribed;
-Antibiotics, NSAIDs for the first two weeks
-Glucosamine chondroitin for one month beginning from the first day of the 4th (21th day postoperatively).
-administer analgesics and pain killers which are vital to recovery and overall wellbeing.
Within 14 days of the surgery
-Your dog should be weight bearing on the limb. This means he/she will be able to stand on the leg but will be toe touching at the walk.
By the 8th week postoperative
-Dog should be able to take two 20-minutes leash walks per day
When starting physical therapy
-Remember to go slowly and stop the session if your dog seems uncomfortable – trying to bite, kicking off you with the unaffected limb or vocalizing.
12.PASSIVE RANGE OF MOTION (ROM) and stretching exercises
-Should begin once your pet is three days postoperatively.
-Your pet standing or laying on side (Laying position is preferred)
-Two persons are handling the dog- one to fix the head and one to perform the exercise.
-Begin by grasping the paw of the operated limb (Below the level of the hock joint) with one hand and with the other hand hold the thigh just above the knee.
-Then slowly flex the knee toward the body until you feel resistance or sense discomfort.
-Hold for 10 seconds and then slowly extend the limb to a normal “standing” position.
-Repeat these exercises 10 to 20 times 2- 4 times daily during the 1st month after TPLO.
-By about the 4th week out from surgery most pets have forgotten they have had surgery! This time will be harder for the owner than the patient. It is necessary to follow all restrictions to the 8th week of recovery to allow the complete healing to occur. Just because your pet does not display pain does not mean the healing is completed!
13.Weeks 4-8 post TPLO:
-Start with slow walks and a short leash on level ground for 5 to 10 minutes 2 to 3 times a day.
-Move slow enough to ensure the limb is used in every step.
-Gradually increase the time you walk and the number of walks you go on a day.
-Your pet will benefit more from increasing the number of walks rather than fewer walks covering more distance.
-You should work up to about 20 minutes 2-3 times per day.
-Program ; 10 minutes leash walks/3T per day/3D then, 5 minutes leash walks/6T per day/3D then, 10 minutes leash walks/4T per day/3D then 20 minutes leash walks/2T per day/3D then, 20 minutes leash walks/3T per day/3D.
14.Week 8 and After:
-Gradually increase your dog’s walks to 1 Kilometer in 15 to 20 minutes – working slowly up 10 kilometers a week.
-Slow stair climbing (both up and down) should be introduced but must be done on a leash to encourage full weight bearing and pushing off with the affected limb.
-Jogging slowly for 2 to 5 minutes at a time 3 to 4 times daily.
-Gradually increase the number of times and duration of the run.